Sw flowsimulation 2009 tutorial

SolidWorks Flow Simulation 2009
Tutorial

First Steps - Ball Valve Design
Contents
Open the SolidWorks Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Create a Flow Simulation Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Define the Engineering Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Solution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Monitor the Solver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Adjust Model Transparency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Cut Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Surface Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Isosurface Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Flow Trajectory Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
XY Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
Surface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Analyze a Design Variant in the SolidWorks Ball part. . . . . . . . . . . . . . . . . . . . . . 1-19
Clone the Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
Analyze a Design Variant in the Flow Simulation Application . . . . . . . . . . . . . . . 1-23
Flow Simulation 2009 Tutorial i

First Steps - Conjugate Heat Transfer
Open the SolidWorks Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Preparing the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Create a Flow Simulation Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Define the Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Define the Boundary Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Define the Heat Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Create a New Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Define the Solid Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Define the Engineering Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Specifying Volume Goals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Specifying Surface Goals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Specifying Global Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Changing the Geometry Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
Viewing the Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
Flow Trajectories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
Cut Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Surface Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
ii Flow Simulation 2009 Tutorial

First Steps - Porous Media
Open the SolidWorks Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
Create a Flow Simulation Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
Define the Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
Create an Isotropic Porous Medium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
Define the Porous Medium - Isotropic Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
Specifying Surface Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
Define the Equation Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-11
Viewing the Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-12
Flow Trajectories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13
Clone the Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-14
Create a Unidirectional Porous Medium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
Define the Porous Medium - Unidirectional Type . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
Compare the Isotropic and Unidirectional Catalysts . . . . . . . . . . . . . . . . . . . . . . . .3-16
Determination of Hydraulic Loss
Model Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2
Creating a Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3
Specifying Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7
Specifying Surface Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-8
Running the Calculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-9
Monitoring the Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10
Cloning the Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10
Creating a Cut Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-11
Working with Parameter List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-14
Creating a Goal Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-15
Working with Calculator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-16
Changing the Geometry Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-18
Flow Simulation 2009 Tutorial iii

Cylinder Drag Coefficient
Creating a Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Specifying 2D Plane Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Specifying a Global Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Specifying an Equation Goal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Cloning a Project and Creating a New Configuration. . . . . . . . . . . . . . . . . . . . . . . . 5-8
Changing Project Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Changing the Equation Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
Creating a Template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Creating a Project from the Template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Solving a Set of Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Getting Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Heat Exchanger Efficiency
Open the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Creating a Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Symmetry Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Specifying a Fluid Subdomain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Specifying Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Specifying Solid Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Specifying a Volume Goal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Running the Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13
Viewing the Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13
Creating a Cut Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Displaying Flow Trajectories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Computation of Surface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
Calculating the Heat Exchanger Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
Specifying the Parameter Display Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
iv Flow Simulation 2009 Tutorial

Mesh Optimization
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-2
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
Project Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
Manual Specification of the Minimum Gap Size. . . . . . . . . . . . . . . . . . . . . . . . . . . .7-7
Switching off the Automatic Mesh Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-9
Specifying Control Planes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-12
Creating a Second Local Initial Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-14
Application of EFD Zooming
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-1
Two Ways of Solving the Problem with Flow Simulation. . . . . . . . . . . . . . . . . . . . .8-3
The EFD Zooming Approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
First Stage of EFD Zooming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4
Project for the First Stage of EFD Zooming. . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-4
Second Stage of EFD Zooming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9
Project for the Second Stage of EFD Zooming . . . . . . . . . . . . . . . . . . . . . . . . . .8-9
Changing the Heat Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-15
Clone Project to the Existing Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . .8-15
The Local Initial Mesh Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-16
Flow Simulation Project for the Local Initial Mesh Approach (Sink No1) . . . .8-16
Flow Simulation Project for the Local Initial Mesh Approach (Sink No2) . . . .8-20
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-20
Flow Simulation 2009 Tutorial v

Textile Machine
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
Project Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
Specifying Rotating Walls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Initial Conditions - Swirl. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
Specifying Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Results - Smooth Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7
Displaying Particles Trajectories and Flow Streamlines. . . . . . . . . . . . . . . . . . . . . . 9-8
Modeling Rough Rotating Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
Adjusting Wall Roughness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
Results - Rough Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12
Non-Newtonian Flow in a Channel with Cylinders
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Specifying Non-Newtonian Liquid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Project Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
Specifying Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3
Comparison with Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Changing Project Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Heated Ball with a Reflector and a Screen
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2
Case 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
Project Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
Definition of the Computational Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
Adjusting Automatic Mesh Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4
Definition of Radiative Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4
Specifying Bodies Transparent to the Heat Radiation. . . . . . . . . . . . . . . . . . . . 11-5
vi Flow Simulation 2009 Tutorial

Heat Sources and Goals Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-5
Case 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6
Changing the Radiative Surface Condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-6
Goals Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7
Specifying Initial Condition in Solid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7
Case 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-7
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-8
Rotating Impeller
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-2
Project Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-2
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-3
Specifying Stationary Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-4
Impeller’s Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-5
Specifying Project Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-5
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-8
CPU Cooler
Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1
SolidWorks Model Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1
Project Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-2
Computational Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-2
Rotating Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-3
Specifying Stationary Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-5
Solid Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-6
Heat Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-6
Initial Mesh Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-6
Specifying Project Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-9
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-11
Flow Simulation 2009 Tutorial vii

viii Flow Simulation 2009 Tutorial

Features List
Below is the list of the physical and interface features of Flow Simulation as they appear
in the tutorial examples. To learn more about the usage of a particular feature, read the
corresponding example.
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
DIMENSIONALITY
2D flow 9
3D flow 99 999 999 999 999 999 999 999 999 999 999 99
Flow Simulation 2009 Tutorial 1

2
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
ANALYSIS TYPE
External analysis 99 999 99
Internal analysis 99 999 999 999 999 999 999 999 999 99
PHYSICAL FEATURES
Steady state analysis 99 999 999 999 999 999 999 999 999 999 999 999 99
Time-dependent (transient)
9
analysis
Liquids 99 999 999 999 99
Gases 99 999 999 999 999 999 999 99
Non-Newtonian liquids 9
Multi-species flows (or more than
99 99
one fluid in the analysis)
Fluid Subdomains 9
Heat conduction in solids 99 999 999 999 99
Heat conduction in solids only 9
Gravitational effects 9

Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Laminar only flow 9
Porous media 99 99
Radiation 9
Roughness 9
Two-phase flows (fluid flows with
9
particles or droplets)
Rotation
Global rotating reference frame 9
Local rotating regions 9
CONDITIONS
Computational domain 99 999 999 99
Symmetry 99 99
Initial and ambient conditions
Velocity parameters 9
Dependency 9

4
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Thermodynamic parameters 99 99
Turbulence parameters 9
Concentration 9
Solid parameters 9
Boundary conditions
Flow openings
Inlet mass flow 99 999 99
Inlet volume flow 99 999 99
Outlet volume flow 9
Inlet velocity 99 999 99
Pressure openings
Static pressure 99 999 999 999 99
Environment pressure 99 999 999 999 99
Wall
Real wall 99 999 99

Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Boundary condition parameters 99 999 999 999 999 999 999 99
Transferred boundary conditions 9
Fans 99 99
Volume conditions
Fluid Subdomain 9
Initial conditions
Velocity parameters 9
Dependency 9
Solid parameters 9
Solid material 99 999 999 999 99
Porous medium 99 99
Heat sources
Surface sources
Heat generation rate 99 99

6
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Volume sources
Temperature 9
Heat generation rate 99 999 99
Radiative surfaces
Blackbody wall 9
Whitebody wall 9
PROJECT DEFINITION
Wizard and Navigator 99 999 999 999 999 999 999 999 999 999 999 999 99
From template 9
Clone project 99 999 999 999 999 999 999 99
General settings 99 99
Copy project’s features 9
GOALS
Global goal 99 999 999 999 99
Surface goal 99 999 999 999 999 999 999 999 999 99

Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Volume goal 99 999 999 999 99
Point goal 9
Equation goal 99 999 999 999 99
MESH SETTINGS
Initial mesh
Automatic settings
Level of initial mesh 99 99
Minimum gap size 99 999 999 999 999 999 999 999 99
Minimum wall thickness 99 999 99
Manual adjustments
Control planes 99 99
Solid/fluid interface 99 99
Narrow channels 99 99
Local initial mesh
Manual adjustments

8
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
Refining cells 9
Narrow channels 99 99
TOOLS
Dependency 99 99
Custom units 99 99
Engineering database
User-defined items 99 999 999 99
Check geometry 9
Gasdynamic calculator 9
Toolbars 9
Filter faces 99 999 99
Component control 99 999 999 999 99
Radiation transparent bodies 9
CALCULATION CONTROL OPTIONS
Result resolution level 99 999 999 99

Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler
RUNNING CALCULATION
Batch run 99 999 99
MONITORING CALCULATION
Goal plot 9
Preview 9
GETTING RESULTS
Cut plot 99 999 999 999 999 999 99
Surface plot 99 99
Isosurfaces 9
Flow trajectories 99 999 999 999 99
Particle study 9
XY plot 9
Surface parameters 99 99
Goal plot 99 999 999 999 999 999 999 99
Display parameters 9

10
Display mode
Show/Hide model geometry 99 999 99
Transparency 99 99
Apply lighting 9
View settings
Contours 99 999 999 99
Vectors 99 999 99
Flow trajectories 9
Isosurfaces 9
OPTIONS
Use CAD geometry 9
Display mesh 9
Mesh Optimization
Textile Machine
Rotating Impeller
CPU Cooler

1
This First Steps tutorial covers the flow of water through a ball valve assembly before and
after some design changes. The objective is to show how easy fluid flow simulation can be
using Flow Simulation and how simple it is to analyze design variations. These two factors
make Flow Simulation the perfect tool for engineers who want to test the impact of their
design changes.
Open the SolidWorks Model
1 Copy the First Steps - Ball Valve folder into your working directory and ensure that
the files are not read-only since Flow Simulation will save input data to these files.
Run Flow Simulation.
2 Click File, Open. In the Open dialog box, browse to the
Ball Valve.SLDASM assembly located in the
First Steps - Ball Valve folder and click Open (or
double-click the assembly). Alternatively, you can drag
and drop the Ball Valve.SLDASM file to an empty
area of SolidWorks window. Make sure, that the default
configuration is the active one.
This is a ball valve. Turning the handle closes or opens
the valve. The mate angle controls the opening angle.
3 Show the lids by clicking the features in the
FeatureManager design tree (Lid <1> and Lid <2>).
We utilize this model for the Flow Simulation simulation without many significant
changes. The user simply closes the interior volume using extrusions we call lids. In
this example the lids are made semi-transparent so one may look into the valve.
Flow Simulation 2009 Tutorial 1-1

Chapter 1 First Steps - Ball Valve Design
Create a Flow Simulation Project
1-2
1 Click Flow Simulation, Project,
Wizard.
2 Once inside the Wizard, select Create
new in order to create a new
configuration and name it Project 1.
Flow Simulation will create a new
configuration and store all data in a
new folder.
Click Next.
3 Choose the system of units (SI for this
project). Please keep in mind that after
finishing the Wizard you may change
the unit system at any time by clicking
Flow Simulation, Units.
Within Flow Simulation, there are
several predefined systems of units. You
can also define your own and switch
between them at any time.
Click Next.
4 Leave the default Internal analysis type.
Do not include any physical features.
We want to analyze the flow through the
structure. This is what we call an internal
analysis. The alternative is an external
analysis, which is the flow around an
object. In this dialog box you can also
choose to ignore cavities that are not
relevant to the flow analysis, so that Flow
Simulation will not waste memory and
CPU resources to take them into account.
Not only will Flow Simulation calculate the fluid flow, but can also take into account
heat conduction within the solid(s) including surface-to-surface radiation. Transient
(time dependent) analyses are also possible. Gravitational effects can be included for
natural convection cases. Analysis of rotating equipment is one more option available.
We skip all these features, as none of them is needed in this simple example.
Click Next.

5 In the Fluids tree expand the Liquids item
and choose Water as the fluid. You can
either double-click Water or select the
item in the tree and click Add.
Flow Simulation is capable of calculating
fluids of different types in one analysis,
but fluids must be separated by the walls.
A mixing of fluids may be considered only
if the fluids are of the same type.
Flow Simulation has an integrated database containing several liquids, gases and
solids. Solids are used for conduction in conjugate heat conduction analyses. You can
easily create your own materials. Up to ten liquids or gases can be chosen for each
analysis run.
Flow Simulation can calculate analyses with any flow type: Turbulent only, Laminar
only or Laminar and Turbulent. The turbulent equations can be disregarded if the flow
is entirely laminar. Flow Simulation can also handle low and high Mach number
compressible flows for gases. For this demonstration we will perform a fluid flow
simulation using a liquid and will keep the default flow characteristics.
Click Next.
6 Click Next accepting the default wall
conditions.
Since we did not choose to consider heat
conduction within the solids, we have an
option of defining a value of heat
conduction for the surfaces in contact with
the fluid. This step is the place to set the
default wall type. Leave the default
Adiabatic wall specifying the walls are
perfectly insulated.
You can also specify the desired wall roughness value applied by default to all model
walls. To set the roughness value for a specific wall, you can define a Real Wall
boundary condition. The specified roughness value is the Rz value.

1-4
7 Click Next accepting the default for the
initial conditions.
On this step we may change the default
settings for pressure, temperature and
velocity. The closer these values are set
to the final values determined in the
analysis, the quicker the analysis will
finish. Since we do not have any
knowledge of the expected final values,
we will not modify them for this
demonstration.
8 Accept the default for the Result
Resolution.
Result Resolution is a measure of the desired level of accuracy of the results. It controls
not only the resolution of the mesh, but also sets many parameters for the solver, e.g.
the convergence criteria. The higher the Result Resolution, the finer the mesh will be
and the stricter the convergence criteria will be set. Thus, Result Resolution determines
the balance between results precision and computation time. Entering values for the
minimum gap size and minimum wall thickness is important when you have small
features. Setting these values accurately ensures your small features are not “passed
over” by the mesh. For our model we type the value of the minimum flow passage as the
minimum gap size.
Click the Manual specification of the minimum gap size box. Enter the value
0.0093 m for the minimum flow passage.
Click Finish.
Now Flow Simulation creates a new configuration with the Flow Simulation data
attached.
Click on the Configuration Manager to show the new configuration.
Notice the name of the new configuration
has the name you entered in the Wizard.

Go to the Flow Simulation Analysis Tree and open all the icons.
We will use the Flow Simulation Analysis Tree to define
our analysis, just as the FeatureManager design tree is
used to design your models. The Flow Simulation
analysis tree is fully customizable; you can select which
folders are shown anytime you work with Flow
Simulation and which folders are hidden. A hidden
folder become visible when you add a new feature of
corresponding type. The folder remains visible until the
last feature of this type is deleted.
Right-click the Computational Domain icon and select
Hide to hide the black wireframe box.
The Computational Domain icon is used to modify the
size and visualization of the volume being analyzed.
The wireframe box enveloping the model is the
visualization of the limits of the computational domain.
Boundary Conditions
A boundary condition is required anywhere fluid enters or exits the system and can be
set as a Pressure, Mass Flow, Volume Flow or Velocity.
1 In the Flow Simulation Analysis Tree,
right-click the Boundary Conditions icon
and select Insert Boundary Condition.
2 Select the inner face of the Lid <1> part as
shown. (To access the inner face, right-click
the Lid <1> in the graphics area and choose
Select Other , hover the pointer over
items in the list of items until the inner face
is highlighted, then click the left mouse
button).

1-6
3 Select Flow Openings and Inlet Mass Flow.
4 Set the Mass Flow Rate Normal to Face to 0.5 kg/s.
5 Click OK . The new Inlet Mass Flow 1 item
appears in the Flow Simulation Analysis tree.
With the definition just made, we told Flow Simulation that at this opening 0.5
kilogram of water per second is flowing into the valve. Within this dialog box we can
also specify a swirl to the flow, a non-uniform profile and time dependent properties to
the flow. The mass flow at the outlet does not need to be specified due to the
conservation of mass; mass flow in equals mass flow out. Therefore another different
condition must be specified. An outlet pressure should be used to identify this
condition.
6 Select the inner face of the Lid <2> part as
shown. (To access the inner face, right-click
the Lid <2> in the graphics area and choose
Select Other , hover the pointer over items
in the list of items until the inner face is
highlighted, then click the left mouse button).
7 In the Flow Simulation Analysis Tree, right-click
the Boundary Conditions icon and
select Insert Boundary Condition.

8 Select Pressure Openings and Static Pressure.
9 Keep the defaults in Thermodynamic Parameters,
Turbulence Parameters, Boundary Layer and Options group boxes.
10 Click OK . The new Static Pressure 1 item appears in
the Flow Simulation Analysis tree.
With the definition just made, we told Flow Simulation that at this opening the fluid
exits the model to an area of static atmospheric pressure. Within this dialog box we can
also set time dependent properties to the pressure.
Define the Engineering Goal
1 Right-click the Flow Simulation Analysis Tree
Goals icon and select Insert Surface Goals.

1-8
2 Click the Flow Simulation Analysis Tree tab and click
the Inlet Mass Flow 1 item to select the face where it is
going to be applied.
3 In the Parameter table select the Av check box in
the Static Pressure row. Already selected Use
for Conv. (Use for Convergence Control) check
box means that the created goal will be used for
convergence control.
If the Use for Conv. (Use for Convergence
Control) check box is not selected for a goal, it will not influence the task stopping
criteria. Such goals can be used as monitoring parameters to give you additional
information about processes occurring in your model without affecting the other
results and the total calculation time.
4 Click OK . The new SG Av Static Pressure 1 item
Engineering goals are the parameters which the user is interested in. Setting goals is in
essence a way of conveying to Flow Simulation what you are trying to get out of the
analysis, as well as a way to reduce the time Flow Simulation needs to reach a
solution. By setting a variable as a project goal you give Flow Simulation information
about variables that are important to converge upon (the variables selected as goals)
and variables that can be less accurate (the variables not selected as goals) in the
interest of time. Goals can be set throughout the entire domain (Global Goals), within
a selected volume (Volume Goals), in a selected surface area (Surface Goals), or at
given point (Point Goals). Furthermore, Flow Simulation can consider the average
value, the minimum value or the maximum value for goal settings. You can also define

an Equation Goal that is a goal defined by an equation involving basic mathematical
functions with existing goals as variables. The equation goal allows you to calculate
the parameter of interest (i.e., pressure drop) and keeps this information in the project
for later reference.
Click File, Save.
Solution
1 Click Flow Simulation, Solve, Run.
The already selected Load results check box means
that the results will be automatically loaded after
finishing the calculation.
2 Click Run.
The solver should take less than a minute to run on a
typical PC.
Monitor the Solver
This is the solution
monitor dialog box. On
the left is a log of each
step taken in the solution
process. On the right is an
information dialog box
with mesh information and
any warnings concerning
the analysis. Do not be
surprised when the error
message “A vortex crosses
the pressure opening”
appear. We will explain
this later during the
demonstration.

1-10
1 After the calculation has started and several first iterations has passed (keep your eye
on the Iterations line in the Info window), click the Suspend button on the
Solver toolbar.
We employ the Suspend option only due to extreme simplicity of the current example,
which otherwise could be calculated too fast, leaving you not enough time to perform
the subsequent steps of result monitoring. Normally you may use the monitoring tools
without suspending the calculation.
2 Click Insert Goal Plot on the Solver toolbar. The Add/Remove Goals dialog
box appears.
3 Select the SG Average Static Pressure 1 in the
Select goals list and click OK.
This is the Goals dialog box and
each goal created earlier is listed
above. Here you can see the current
value and graph for each goal as
well as the current progress towards
completion given as a percentage.
The progress value is only an
estimate and the rate of progress
generally increases with time.
4 Click Insert Preview on the Solver toolbar.

5 This is the Preview Settings dialog box.
Selecting any SolidWorks plane from the
Plane name list and pressing OK will
create a preview plot of the solution in
that plane. For this model Plane2 is a
good choice to use as the preview plane.
The preview allows one to look at
the results while the calculation is
still running. This helps to
determine if all the boundary
conditions are correctly defined
and gives the user an idea of how
the solution will look even at this
early stage. At the start of the run
the results might look odd or
change abruptly. However, as the run progresses these changes will lessen and the
results will settle in on a converged solution. The result can be displayed either in
contour-, isoline- or vector-representation.
6 Click the Suspend button again to let the solver go on.
7 When the solver is finished, close the monitor by clicking File, Close.
Adjust Model Transparency
Click Flow Simulation, Results, Display, Transparency
and set the model transparency to 0.75.
The first step for results is to generate a transparent view
of the geometry, a ‘glass-body’. This way you can easily
see where cut planes etc. are located with respect to the
geometry.
Cut Plots
1 In the Flow Simulation Analysis tree, right-click the Cut
Plots icon and select Insert.

1-12
2 Specify a plane. Choose Plane 2 as
the cut plane. To do this, in the flyout
FeatureManager design tree select
Plane 2.
3 Click OK .
This is the plot you should see.
A cut plot displays any result on any SolidWorks plane.
The results may be represented as a contour plot, as
isolines, as vectors, or as arbitrary combination of the
above (e.g. contours with overlaid vectors).
If you want to access additional options
for this and other plots, you may either
double-click on the color scale or right-click
the Results icon in the Flow
Simulation Analysis tree and select View
Settings.
Within the View Settings dialog box you
have the ability to change the global
options for each plot type. Some options
available are: changing the parameter being displayed and the number of colors used
for the scale. The best way to learn each of these options is thorough experimentation.
4 Change the contour cut plot to a vector cut plot. To do
this, right-click the Cut Plot 1 icon and select Edit
Definition.

5 Clear Contours and select Vectors .
6 Click OK .
This is the plot you should see.
The vectors can be made larger from the Vectors tab in
the View Setting dialog box. The vector spacing can also
be controlled from the Settings tab in the Cut Plot dialog
box. Notice how the flow must navigate around the
sharp corners on the Ball. Our design change will focus
on this feature.
Surface Plots
Right-click the Cut Plot 1 icon and select Hide.
1 Right-click the Surface Plots icon and select Insert.
2 Select the Use all faces check box.
The same basic options are available for Surface Plots
as for Cut Plots. Feel free to experiment with different
combinations on your own.

1-14
3 Click OK and you get the following picture:
This plot shows the pressure distribution on all faces of
the valve in contact with the fluid. You can also select
one or more single surfaces for this plot, which do not
have to be planar.
Isosurface Plots
Right-click the Surface Plot 1 icon and select Hide.
1 Right-click the Isosurfaces icon and select Show.
This is the plot that will appear.
The Isosurface is a 3-Dimensional surface created by
Flow Simulation at a constant value for a specific
variable. The value and variable can be altered in the
View Settings dialog box under the Isosurfaces tab.
2 Right-click the Results icon and select View Settings to
enter the dialog.
3 Go to Isosurfaces tab.
4 Examine the options under this dialog box.
Try making two changes. The first is to
click in the Use from contours so that the
isosurface will be colored according to the
pressure values, in the same manner as the
contour plot.
5 Secondly, click at a second location on the
slide bar and notice the addition of a
second slider. This slider can later be
removed by dragging it all the way out of
the dialog box.
6 Click OK.

You should see something similar to this image.
The isosurface is a useful way of determining the exact
3D area, where the flow reaches a certain value of
pressure, velocity or other parameter.
Flow Trajectory Plots
Right-click the Isosurfaces icon and select Hide.
1 Right-click the Flow Trajectories icon and select Insert.

1-16
2 Click the Flow Simulation Analysis Tree tab and then
click the Static Presuure 1 item to select the inner
face of the Lid <2>.
3 Set the Number of Trajectories to 16..
4 Click OK and your model should look like the
following:
Using Flow trajectories you can show the flow
streamlines. Flow trajectories provide a very good image
of the 3D fluid flow. You can also see how parameters
change along each trajectory by exporting data into
Excel. Additionally, you can save trajectories as
SolidWorks reference curves.
For this plot we selected the outlet lid (any flat face or
sketch can be selected) and therefore every trajectory crosses that selected face. The
trajectories can also be colored by values of whatever variable chosen in the View
Settings dialog box. Notice the trajectories that are entering and exiting through the

exit lid. This is the reason for the warning we received during the calculation. Flow
Simulation warns us of inappropriate analysis conditions so that we do not need to be
CFD experts. When flow both enters and exits the same opening, the accuracy of the
results will worsen. In a case like this, one would typically add the next component to
the model (say, a pipe extending the computational domain) so that the vortex does not
occur at opening.
XY Plots
Right-click the Flow Trajectories 1 icon and select Hide.
We want to plot pressure and velocity along the valve. We
have already created a SolidWorks sketch containing
several lines.
This sketch work does not have to be done ahead of time
and your sketch lines can be created after the analysis has
finished. Take a look at Sketch1 in the FeatureManager
design tree.
1 Right-click the XY Plots icon and select Insert.

1-18
2 Choose Velocity and Pressure as
physical Parameters. Select Sketch1
from the flyout FeatureManager design
tree.
Leave all other options as defaults.
3 Click OK. MS Excel will
open and generate two
columns of data points
together with two charts for
Velocity and for Pressure,
respectively. One of these
charts is shown below. You
will need to toggle between
different sheets in Excel to
view each chart.
The XY Plot allows you to
view any result along
sketched lines. The data is
put directly into Excel.
8
7
6
5
4
3
2
1
0
-1
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
Curve Length (m)
Velocity (m/s)

Surface Parameters
Surface Parameters is a feature used to determine pressures, forces, heat fluxes as well as
many other variables on any face within your model contacting the fluid. For this type of
analysis, a calculation of the average static pressure drop from the valve inlet to outlet
would probably be of some interest.
1 Right-click the Surface Parameters icon and select
Insert.
2 In the Flow Simulation Analysis
Tree, click the Inlet Mass Flow1 item
to select the inner face of the inlet
Lid <1> part.
3 Click Evaluate.
4 Select the Local tab.
The average static pressure at the inlet face
is shown to be 128478 Pa. We already know
that the outlet static pressure is 101325 Pa
since we have specified it previously as a
boundary condition. So, the average static
pressure drop through the valve is about
27000 Pa.
5 Close the Surface Parameters dialog box.
Analyze a Design Variant in the SolidWorks Ball part
This section is intended to show you how easy it is to analyze design variations. The
variations can be different geometric dimensions, new features, new parts in an
assembly – whatever! This is the heart of Flow Simulation and this allows design
engineers to quickly and easily determine which designs have promise, and which
designs are unlikely to be successful. For this example, we will see how filleting two
sharp edges will influence the pressure drop through the valve. If there is no
improvement, it will not be worth the extra manufacturing costs.
Create a new configuration using the SolidWorks Configuration Manager Tree.

1-20
1 Right-click the root item in the SolidWorks
Configuration Manager and select Add
Configuration.
2 In the Configuration Name box type
Project 2.
3 Click OK .
4 Go to FeatureManager design tree, right-click the
Ball item and select Open Part . A new
window Ball.SLDPRT appears.
Create a new configuration using the SolidWorks
Configuration Manager Tree.

1 Right-click the root item in the SolidWorks
Configuration Manager and select Add
Configuration.
2 Name the new configuration as
1,5_fillet Ball.
3 Click OK .
4 Add a 1,5 mm
fillet to the
shown face.

1-22
5 Switch back to the assembly
window and select Yes in the
message dialog box that appears. In
the FeatureManager design tree
right-click the Ball item and select
Component Properties.
6 At the bottom of the Component
Properties dialog box, under
Referenced configuration change
the configuration of the Ball part to
the new filleted one.
7 Click OK to confirm and close the dialog.
Now we have replaced the old ball with our new
1.5_fillet Ball. All we need to do now is re-solve
the assembly and compare the results of the two
designs. In order to make the results comparable
with the previous model, it would be necessary to
adjust the valve angle to match the size of the flow
passage of the first model. In this example, we will
not do this.
8 Activate Project 1 by using the
Configuration Manager Tree. Select Yes
for the message dialog box that appears.

Clone the Project
1 Click Flow Simulation, Project, Clone Project.
2 Select Add to existing.
3 In the Existing configuration list select Project 2.
4 Click OK. Select Yes for each message dialog box that
appears after you click OK.
Now the Flow Simulation project we have chosen is added to the SolidWorks project
which contains the geometry that has been changed. All our input data are copied, so
we do not need to define our openings or goals again. The Boundary Conditions can be
changed, deleted or added. All changes to the geometry will only be applied to this new
configuration, so the old results are still saved.
Please follow the previously described steps for solving and for viewing the results.
Analyze a Design Variant in the Flow Simulation Application
In the previous sections we examined how you could compare results from different
geometries. You may also want to run the same geometry over a range of flow rates.
This section shows how quick and easy it can be to do that kind of parametric study.
Here we are going to change the mass flow to 0.75 kg/s.
Activate the Project 1 configuration.
1 Create a copy of the Project 1 project by clicking
Flow Simulation, Project, Clone Project.
2 Type Project 3 for the new project name and click
OK.
Flow Simulation now creates a new configuration. All our input data are copied, so we do
not need to define our openings or goals again. The Boundary Conditions can be changed,
deleted or added. All changes to the geometry will only be applied to this new
configuration, so the old results remain valid. After changing the inlet flow rate value to
0.75 kg/s you would be ready to run again. Please follow the previously described steps
for solving and for viewing the results.

1-24
Imagine being the designer of this ball valve. How would you make decisions concerning
your design? If you had to determine whether the benefit of modifying the design as we
have just done outweighted the extra costs, how would you do this? Engineers have to
make decisions such as this every day, and Flow Simulation is a tool to help them make
those decisions. Every engineer who is required to make design decisions involving fluid
and heat transfer should use Flow Simulation to test their ideas, allowing for fewer
prototypes and quicker design cycles.

2
This First Steps - Conjugate Heat Transfer tutorial covers the basic steps to set up a flow
analysis problem including heat conduction in solids. This example is particularly
pertinent to users interested in analyzing flow and heat conduction within electronics
packages although the basic principles are applicable to all thermal problems. It is
assumed that you have already completed the First Steps - Ball Valve Design tutorial
since it teaches the basic principles of using Flow Simulation in greater detail.
1 Copy the First Steps - Electronics Cooling folder into your working directory and
ensure that the files are not read-only since Flow Simulation will save input data to
these files. Click File, Open.
2 In the Open dialog box, browse to the Enclosure Assembly.SLDASM assembly
located in the First Steps - Electronics Cooling folder and click Open (or
double-click the assembly). Alternatively, you can drag and drop the
Enclosure Assembly.SLDASM file to an empty area of SolidWorks window.

Chapter 2 First Steps - Conjugate Heat Transfer
Preparing the Model
2-2
In a typical assembly there may be many features, parts or sub-assemblies that are not
necessary for the analysis. Prior to creating an Flow Simulation project, it is a good
practice to check the model to find components that can be removed from the analysis.
Excluding these components reduces the computer resources and calculation time
required for the analysis.
The assembly consists of the following components: enclosure, motherboard and two
smaller PCBs, capacitors, power supply, heat sink, chips, fan, screws, fan housing, and
lids. You can highlight these components by clicking on the them in the FeatureManager
design tree. In this tutorial we will simulate the fan by specifying a Fan boundary
condition on the inner face of the inlet lid. The fan has a very complex geometry that may
cause delays while rebuilding the model. Since it is outside the enclosure, we can exclude
it by suppressing it.
1 In the FeatureManager design tree, select
the Fan-412, and all Screws components
(to select more than one component, hold
down the Ctrl key while you select).
2 Right-click any of the selected
components and select Suppress ..
Inlet Fan
PCBs
Small Chips
Main Chip
Capacitors
Power Supply
Mother Board
Heat Sink

Suppressing fan and its screws leaves open five holes in the enclosure. We are going to
perform an internal analysis, so all holes must be closed with lids. It can be done with
the lid creation tool avalilable under Flow Simulation, Tools, Create Lids.
To save your time, we created the lids and included them to the model. You just need to
unsupress them..
3 In the FeatureManager design tree,
select the Inlet Lid, Outlet Lid and
Screwhole Lid components and
patterns DerivedLPattern1 and
LocalLPattern1 (these patterns contain
cloned copies of the outlet and
screwhole lids).
4 Right-click any of the selected
components and select
Unsuppress .
Now you can start with Flow Simulation.
1 Click Flow Simulation, Project, Wizard.
2 Once inside the Wizard, select Create new
in order to create a new configuration and
name it Inlet Fan.
Click Next.
Now we will create a new system of units
named USA Electronics that is better
suited for our analysis.
3 In the Unit system list select the USA
system of units. Select Create new to
add a new system of units to the
Engineering Database and name it
USA Electronics.
Flow Simulation allows you to work with
several pre-defined unit systems but often
it is more convenient to define your own

2-4
custom unit system. Both pre-defined and custom unit systems are stored in the
Engineering Database. You can create the desired system of units in the Engineering
Database or in the Wizard.
By scrolling through the different groups in the Parameter tree you can see the units
selected for all the parameters. Although most of the parameters have convenient units
such as ft/s for velocity and CFM (cubic feet per minute) for volume flow rate we will
change a couple units that are more convenient for this model. Since the physical size
of the model is relatively small it is more convenient to choose inches instead of feet as
the length unit.
4 For the Length entry, double-click its cell
in the Units column and select Inch.
5 Next expand the Heat group in the
Parameter tree.
Since we are dealing with electronic
components it is more convenient to
specify Total heat flow and power and
Heat flux in Watt and Watt/m2
respectively.
Click Next.
6 Set the analysis type to Internal. Under
Physical Features select the Heat
conduction in solids check box.
Heat conduction in solids was selected
because heat is generated by several
electronics components and we are
interested to see how the heat is dissipated
through the heat sink and other solid parts
and then out to the fluid.
Click Next.

7 Expand the Gases folder and double-click
Air row. Keep default Flow
Characteristics.
Click Next.
8 Expand the Alloys folder and click Steel
Stainless 321 to assign it as a Default
solid.
In the Wizard you specify the default solid
material applied to all solid components
in the Flow Simulation project. To specify
a different solid material for one or more
components, you can define a Solid
Material condition for these components
after the project is created.
Click Next.
9 Select Heat transfer coefficient as
Default outer wall thermal condition and
specify the Heat transfer coefficient
value of 5.5 W/m^2/K and External fluid
temperature of 50°F. The entered value
of heat transfer coefficient is
automatically coverted to the selected
system of units (USA Electronics).
In the Wall Conditons dialog box of the
Wizard you specify the default conditions
at the model walls. When Heat
conduction in solids is enabled, the Default outer wall thermal condition
parameter allows you to simulate heat exchange between the outer model walls and
surrounding environment. In our case the box is located in an air-conditioned room
with the air temperature of 50°F and heat transfer through the outer walls of the
enclosure due to the convection in the room can significantly contribute to the
enclosure cooling.
Click Next.
Although the initial temperature is more important for transient calculations to see how
much time it takes to reach a certain temperature, in a steady-state analysis it is useful

2-6
to set the initial temperature close to the anticipated final solution to speed up
convergence. In this case we will set the initial air temperature and the initial
temperature of the stainless steel (which represents the material of enclosure) to 50°F
because the box is located in an air-conditioned room.
10 Set the initial fluid Temperature and the
Initial solid temperature to 50°F.
Click Next.
11 Accept the default for the Result
resolution and keep the automatic
evaluation of the Minimum gap size and
Minimum wall thickness.
Flow Simulation calculates the default
minimum gap size and minimum wall
thickness using information about the
overall model dimensions, the
computational domain, and faces on which
you specify conditions and goals. Prior to
starting the calculation, we recommend that you check the minimum gap size and
minimum wall thickness to ensure that small features will be recognized. We will
review these again after all the necessary conditions and goals will be specified.
Click Finish. Now Flow Simulation creates a new configuration with the Flow
Simulation data attached.
We will use the Flow Simulation Analysis tree to define our analysis, just as the
FeatureManager design tree is used to design your models.
Right-click the Computational Domain icon and select
Hide to hide the wireframe box.
Define the Fan
A Fan is a type of flow boundary condition. You can specify Fans at selected solid
surfaces, free of Boundary Conditions and Sources. At model openings closed by lids
you can specify Inlet or Outlet Fans. You can also specify fans on any faces within the

flow region as Internal Fans. A Fan is considered as an ideal device creating a flow
with a certain volume (or mass) flow rate, which depends on the difference between the
inlet and outlet pressures on the selected faces.
If you analyze a model with a fan, you sholud know the fan's characteristics. In this
example we use one of the pre-defined fans available in the Engineering Database. If you
cannot find an appropriate fan in the Engineering Database, you can create your own fan in
accordance with the fan’s specification.
1 Click Flow Simulation, Insert, Fan. The Fan dialog box appears.
2 Select the inner face of the Inlet
Lid part as shown. (To access
the inner face, right-click the
Inlet Lid in the graphics area
and choose Select Other, hover
the pointer over items in the list
of features until the inner face is
highlighted, then click the left
mouse button).
3 Select External Inlet Fan as fan
Type.
4 In the Fan list select the Papst
412 item under Pre-Defined, Axial, Papst.
5 Under Thermodynamic Parameters check that the
Ambient Pressure is the atmospheric pressure.
6 Accept Face Coordinate System as the reference
Coordinate System .

2-8
Face coordinate system is created automatically in the center of a planar face when
you select this face as the face to apply the boundary condition or fan. The X axis of
this coordinate system is normal to the face. The Face coordinate system is created
when only one planar face is selected.
7 Accept X as the Reference axis.
8 Click OK . The new Fans folder and the External
Inlet Fan 1 item appear in the Flow Simulation Analysis
tree.
Now you can edit the External Inlet Fan1 item or add a new fan
using Flow Simulation Analysis tree. This folder remains visible
until the last feature of this type is deleted. You can also make a
feature’s folder to be initially available in the tree. Right-click the
project name item and select Customize Tree to add or remove
folders.
Since the outlet lids of the enclosure are at ambient atmospheric pressure, the pressure
rise produced by the fan is equal to the pressure drop through the electronics
enclosure.
Define the Boundary Conditions
A boundary condition is required at any place where fluid enters or exits the model,
excluding openings where a fan is specified. A boundary condition can be set in form of
Pressure, Mass Flow, Volume Flow or Velocity. You can also use the Boundary
Condition dialog for specifying an Ideal Wall condition that is an adiabatic, frictionless
wall or a Real Wall condition to set the wall roughness and/or temperature and/or heat
conduction coefficient at the model surfaces. For internal analyses with Heat conduction
in solids enabled, you can also set thermal wall condition on outer model walls by
specifying an Outer Wall condition.
1 In the Flow Simulation analysis tree, right-click the
Boundary Conditions icon and select Insert
Boundary Condition.

2 Select the inner faces of all outlet
lids as shown.
3 Select Pressure Openings
and Environment Pressure.
4 Click OK . The new Environment Pressure 1 item
The Environment pressure condition is interpreted as a
static pressure for outgoing flows and as a total pressure
for incoming flows.
Define the Heat Source
1 Click Flow Simulation, Insert, Volume Source.
2 Select the Main Chip from the
flyout FeatureManager design
tree tree as the component to
apply the volume source.
3 Select the Heat Generation
Rate as Parameter.
4 Enter 5 W in the Heat Generation Rate box.
5 Click OK .
6 In the Flow Simulation Analysis tree click-pause-click the
new VS Heat Generation Rate 1 item and rename it to
Main Chip.

2-10
Volume Heat Sources allow you to specify the heat generation rate (in Watts) or the
volumetric heat generation rate (in Watts per volume) or a constant temperature
boundary condition for the volume. It is also possible to specify Surface Heat Sources
in terms of heat transfer rate (in Watts) or heat flux (in Watts per area).
Click anywhere in the graphic area to clear the selection.
1 In the Flow Simulation analysis tree, right-click the Heat Sources icon and select
Insert Volume Source.
2 In the flyout FeatureManager
design tree select all Capacitor
components.
3 Select Temperature and
enter 100 °F in the Temperature
box.
4 Click OK .
5 Click-pause-click the new VS
Temperature 1 item and rename
it to Capacitors.

6 Following the same procedure as
above, set the following volume
heat sources: all chips on PCBs
(Small Chip) with the total heat
generation rate of 4 W,
Power Supply with
the temperature of 120 °F.
7 Rename the source applied to the chips to Small Chips and
the source for the power supply to Power Supply.
Click File, Save.
Create a New Material
The real PCBs are made of laminate materials consisting of several layers of thin metal
conductor interleaved with layers of epoxy resin dielectric. As for most laminate
materials, the properties of a typical PCB material can vary greatly depending on the
direction - along or across the layers, i.e. they are anisotropic. The Engineering Database
contains some predefined PCB materials with anisotropic thermal conductivity.
In this tutorial example anisotropic thermal conductivity of PCBs does not affect the
overall cooling performance much, so we will create a PCB material having the same
thermal conductivity in all directions to learn how to add a new material to Engineering
Database and assign it to a part.
1 Click Flow Simulation, Tools, Engineering Database.

2-12
2 In the Database tree select Materials, Solids, User Defined.
3 Click New Item on the toolbar.
The blank Item Properties tab appears. Double-click the
empty cells to set the corresponding properties values.
4 Specify the material properties
as follows:
Name = Tutorial PCB,
Comments = Isotropic PCB,
Density = 1120 kg/m^3,
Specific heat = 1400 J/(kg*K),
Conductivity type = Isotropic
Thermal conductivity = 10 W/(m*K),
Melting temperature = 390 K.
We also need to add a new material simulating thermal conductivity and other thermal
properties of the chips material.
5 Switch to the Items tab and click New Item on the toolbar.
6 Specify the properties
of the chips material:
Name = Tutorial
component package,
Comments =
Component package,
Density = 2000 kg/m^3,
Specific heat = 120 J/(kg*K),
Conductivity type = Isotropic
Thermal conductivity = 0.4 W/(m*K),
Melting temperature = 1688.2 K.
7 Click Save .
8 Click File, Exit to exit the database.

You can enter the material properties in any unit system you want by typing the unit
name after the value and Flow Simulation will automatically convert the entered value
to the SI system of units. You can also specify temperature dependent material
properties using the Tables and Curves tab.
Define the Solid Materials
Solid Materials are used to specify the materials for solid parts in the assembly.
1 Right-click the Solid Materials icon and select Insert Solid Material.
design tree select
MotherBoard, PCB<1> and
PCB<2> components.
3 In the Solid list expand User
Defined and select Tutorial
PCB.
4 Click OK .
5 Following the same procedure, specify solid materials for other components:
• for the main chip and all small chips assign the new Tutorial component package
material (available under User Defined);
• the heat sink is made of Aluminum (available under Pre-Defined, Metals);
• the lids (Inlet Lid, Outlet Lid, Screwhole Lid and all lids in both the
DerivedLPattern1 and LocalLPattern1 patterns) are made of the Insulator
material (available under Pre-Defined, Glasses and Minerals).
To select a part, click it in the FeatureManager design tree or SolidWorks graphics
area.
6 Change the name of each assigned solid material. The new,
descriptive names should be:
PCB - Tutorial PCB,
Chips - Tutorial component package,

2-14
Heat Sink - Aluminum,
Lids - Insulator.
Click File, Save.
Define the Engineering Goals
Specifying Volume Goals
1 Right-click the Goals icon and select Insert Volume
Goals.
2 In the flyout FeatureManager design
tree select all Small Chip
components.
3 In the Parameter table select the
Max check box in the Temperature
of Solid row.
4 Accept selected Use for Conv. (Use
for Convergence Control) check
box to use this goal for convergence
control.
5 Click OK . The new VG Max
Temperature of Solid 1 item
appears in the Flow Simulation
Analysis tree.

6 Change the name of the new item to
VG Small Chips Max Temperature. You
can also change the name of the item using the
Feature Properties dialog that appears if you
right-click the item and select Properties.
Click anywhere in the graphic area to clear the
selection.
7 Right-click the Goals icon and select Insert
Volume Goals.
8 Select the Main Chip item in the
flyout FeatureManager design tree.
9 In the Parameter table select the
Max check box in the Temperature
of Solid row.
10 Click OK .
11 Rename the new VG Max
Temperature of Solid 1 item to
VG Chip Max Temperature.
Click anywhere in the graphic area
to clear the selection.
Specifying Surface Goals
1 Right-click the Goals icon and select Insert Surface
Goals.

2-16
2 Click the Flow Simulation Analysis Tree tab
and click the External Inlet Fan 1 item to
select the face where the goal is going to be
applied.
3 In the Parameter table select the Av check box
in the Static Pressure row.
4 Accept selected Use for Conv. (Use for
Convergence Control) check box to use this
goal for convergence control.
For the X(Y, Z) - Component of Force and X(Y,
Z) - Component of Torque surface goals you
can select the Coordinate system in which these
goals will be calculated.
5 Under Name Template, located at the bottom
of the PropertyManager, click Inlet and then remove
the <Number> field from the Name Template box.
6 Click OK . The new SG Inlet Av Static Pressure goal
appears.

7 Right-click the Goals icon and select Insert
Surface Goals.
and click the Environment Pressure 1 item to
select the faces where the goal is going to be
applied.
9 In the Parameter table select the first check
box in the Mass Flow Rate row.
10 Accept selected Use for Conv. (Use for
of the PropertyManager, click Outlet and
then remove the <Number> field from the
Name Template.
12 Click OK - the SG Outlet Mass Flow Rate goal appears.
Specifying Global Goals
1 Right-click the Goals icon and select Insert Global Goals.

2-18
2 In the Parameter table select the Av
check boxes in the Static Pressure and
Temperature of Fluid rows and accept
selected Use for Conv. (Use for
Convergence Control) check box to use
these goals for convergence control.
3 Remove the <Number> field from the
Name Template and click OK - GG Av
Static Pressure and GG Av Temperature of
Fluid goals appear.
In this tutorial the engineering goals are set to determine the maximum temperature of the
heat generating components, the temperature rise in air and the pressure drop and mass
flow rate through the enclosure.
Click File, Save.
Next let us check the automatically defined geometry resolution settings for this project.

Changing the Geometry Resolution
1 Click Flow Simulation, Initial Mesh.
2 Select the Manual specification of the
minimum gap size check box.
3 Enter 0.1 in for the Minimum gap size (i.e. passage
between the fins of the heat sink).
Entering values for the minimum gap size and minimum
wall thickness is important when you have small
features. Setting these values accurately ensures that
the small features are not "passed over" by the mesh.
The minimum wall thickness should be specified only if there are fluid cells on either
side of a small solid feature. In case of internal analyses, there are no fluid cells in the
ambient space outside of the enclosure. Therefore boundaries between internal flow
and ambient space are always resolved properly. That is why you should not take into
account the walls of the steel cabinet. Both the minimum gap size and the minimum
wall thickness are tools that help you to create a model-adaptive mesh resulting in
increased accuracy. However the minimum gap size setting is the more powerful one.
The fact is that the Flow Simulation mesh is constructed so that the specified Level of
initial mesh controls the minimum number of mesh cells per minimum gap size. And
this number is equal to or greater than the number of mesh cells generated per
minimum wall thickness. That's why even if you have a thin solid feature inside the
flow region it is not necessary to specify minimum wall thickness if it is greater than or
equal to the minimum gap size. Specifying the minimum wall thickness is necessary if
you want to resolve thin walls smaller than the smallest gap.
Click OK.

Solution
2-20
2 Click Run.
The solver takes about twenty to thirty minutes to
run on a typical PC.
You may notice that different goals take different
number of iterations to converge.
The goal-oriented philosophy of Flow Simulation
allows you to get the answers you need in the shortest amount of time.
For example, if you were only interested in the temperature of fluid in the enclosure,
Flow Simulation would have provided the result more quickly then if the solver was
allowed to fully converge on all of the parameters.
Viewing the Goals
1 Right-click the Goals icon under Results and select Insert.
2 Click Add All in the Goals dialog.
3 Click OK.

An Excel spreadsheet with the goal results will open. The first sheet will show a table
summarizing the goals.
Enclosure Assembly.SLDASM [Inlet Fan (original)]
Goal Name Unit Value Averaged Value Minimum Value Maximum Value Progress [%] Use In Convergence
GG Av Static Pressure [lbf/in^2] 14.69678696 14.69678549 14.69678314 14.69678772 100 Yes
SG Inlet Av Static Pressure [lbf/in^2] 14.69641185 14.69641047 14.69640709 14.69641418 100 Yes
GG Av Temperature of Fluid [°F] 61.7814683 61.76016724 61.5252449 61.86764155 100 Yes
SG Outlet Mass Flow Rate [lb/s] -0.007306292 -0.007306111 -0.007306913 -0.007303663 100 Yes
VG Small Chips Max Temp [°F] 91.5523903 90.97688632 90.09851988 91.5523903 100 Yes
VG Chip Max Temperature [°F] 88.51909612 88.43365626 88.29145322 88.57515562 100 Yes
You can see that the maximum temperature in the main chip is about 88 °F, and the
maximum temperature over the small chips is about 91 °F.
Goal progress bar is a qualitative and quantitative characteristic of the goal
convergence process. When Flow Simulation analyzes the goal convergence, it
calculates the goal dispersion defined as the difference between the maximum and
minimum goal values over the analysis interval reckoned from the last iteration and
compares this dispersion with the goal's convergence criterion dispersion, either
specified by you or automatically determined by Flow Simulation as a fraction of the
goal's physical parameter dispersion over the computational domain. The percentage
of the goal's convergence criterion dispersion to the goal's real dispersion over the
analysis interval is shown in the goal's convergence progress bar (when the goal's real
dispersion becomes equal or smaller than the goal's convergence criterion dispersion,
the progress bar is replaced by word "Achieved"). Naturally, if the goal's real
dispersion oscillates, the progress bar oscillates also, moreover, when a hard problem
is solved, it can noticeably regress, in particular from the "achieved" level. The
calculation can finish if the iterations (in travels) required for finishing the calculation
have been performed, or if the goal convergence criteria are satisfied before
performing the required number of iterations. You can specify other finishing
conditions at your discretion.
To analyze the results in more detail let us use the various Flow Simulation
post-processing tools. The best method for the visualization of how the fluid flows inside
the enclosure is to create flow trajectories.

Flow Trajectories
2-22
1 Right-click the Flow Trajectories icon and select
Insert.
2 Click the Flow Simulation Analysis Tree tab and
then click the External Inlet Fan1 item to select
the inner face of the Inlet Lid.
3 Set the Number of Trajectories to 200.
4 Keep Reference in the Start Points group.
If Reference is selected, then the trajectory start
points are taken from the specified face.
5 Under Options set Draw Trajectories As to
Bands.
6 Click View Settings.
7 In the View Settings dialog box, change the
Parameter from Pressure to Velocity.
8 Go to the Flow Trajectories tab and notice
that the Use from contours option is
selected.

This setting defines how trajectories are
colored. If Use from contours is selected
then the trajectories are colored with the
distribution of the parameter specified on
the Contours tab (Velocity in our case). If
you select Use fixed color then all flow
trajectories have the same color that you
specify on the Settings tab of the Flow
Trajectories dialog box.
9 Click OK to save the changes and exit the View Settings dialog box.
10 In the Flow Trajectories dialog click OK . The new Flow Trajectories 1 item
This is the picture you should see.
Notice that there are only a few
trajectories along the adjacent to the wall
PCB<2> and this may cause problems
with cooling of the chips placed on this
PCB. Additionally the blue color
indicates low velocity in front of this
PCB<2> .
Right-click the Flow Trajectories 1 item
and select Hide.
Click anywhere in the graphic area to clear the
selection.
Let us examine the velocity distribution in more
detail.

Cut Plots
2-24
1 Right-click the Cut Plots icon and select Insert.
2 Keep the Front plane as the section plane.
4 Change the Min and Max values to 0 and
10 respectively. The specified integer
values produce a palette where it is more
easy to determine the value.
5 Set the Number of colors to about 30.
6 Click OK.
7 In the Cut Plot dialog box click OK .
The new Cut Plot 1 item appears in the Flow Simulation Analysis tree.
8 Select the Top view on the Standard Views toolbar.

Let us now look at the fluid temperature.
9 Double-click the palette bar in the upper left corner of the graphics area. The
View Settings dialog appears.
10 Change the Parameter from Velocity to Fluid Temperature.
120 respectively.
12 Click the Vectors tab and change the
Arrow size to 0.2 by typing the value in the
box under the slider.
Notice that you can specify a value that is
outside of the slider's range.
13 Set the Max value to 1 ft/s.

2-26
By specifying the custom Min and Max values you can control the vector length. The
vectors whose velocity exceeds the specified Max value will have the same length as
the vectors whose velocity is equal to Max. Likewise, the vectors whose velocity is less
than the specified Min value will have the same length as the vectors whose velocity is
equal to Min. We have set 1 ft/s to display areas of low velocity.
14 Click OK.
15 Right-click the Cut Plot 1 item and select Edit
Definition.
16 Click Vectors
17 Change the Offset to -0.30 in.
18 Expand the Vectors group box. Using the slider set the
Vector Spacing to ~ 0.18 in.
19 Click OK .

Right-click the Cut Plot 1 item and select Hide. Let us now display solid temperature.
Surface Plots
1 Right-click the Surface Plots item and select Insert.

2-28
2 In the flyout FeatureManager design tree click the Main
Chip, Heat Sink and all Small Chip components to select
their surfaces.
4 In the View Settings dialog box, change
the Parameter to Solid Temperature.
120 respectively.
6 Click OK.
7 In the Surface Plot dialog box click OK . The creation of the surface plot may
take some time because many faces need to be colored.
8 Repeat steps 1 and 2 and select the Power Supply and all Capacitors components,
then click OK .
9 On the View toolbar click Wireframe to show the face outlines.

You can view and analyze the results further with the post-processing tools that were
shown in the First Steps - Ball Valve Design tutorial. Flow Simulation allows you to
quickly and easily investigate your design both quantitatively and qualitatively.
Quantitative results such as the maximum temperature in the component, pressure drop
through the cabinet, and air temperature rise will allow you to determine whether the
design is acceptable or not. By viewing qualitative results such as air flow patterns, and
heat conduction patterns in the solid, Flow Simulation gives you the necessary insight to
locate problem areas or weaknesses in your design and provides guidance on how to
improve or optimize the design.

2-30

3
In this tutorial we consider flow in a section of an automobile exhaust pipe, whose exhaust
flow is resisted by two porous bodies serving as catalysts for transforming harmful carbon
monoxide into carbon dioxide. When designing an automobile catalytic converter, the
engineer faces a compromise between minimizing the catalyst's resistance to the exhaust
flow while maximizing the catalyst's internal surface area and duration that the exhaust
gases are in contact with that surface area. Therefore, a more uniform distribution of the
exhaust mass flow rate over the catalyst's cross sections favors its serviceability. The
porous media capabilities of Flow Simulation are used to simulate each catalyst, which
allows you to model the volume that the catalyst occupies as a distributed resistance
instead of discretely modeling all of the individual passages within the catalyst, which
would be impractical or even impossible. Here, as a Flow Simulation tutorial example we
consider the influence of the catalysts' porous medium permeability type (isotropic and
unidirectional media of the same resistance to flow) on the exhaust mass flow rate
distribution over the catalysts' cross sections. We will observe the latter through the
behavior of the exhaust gas flow trajectories distributed uniformly over the model's inlet
and passing through the porous catalysts. Additionally, by coloring the flow trajectories
by the flow velocity the exhaust gas residence time in the porous catalysts can be
estimated, which is also important from the catalyst effectiveness viewpoint.

Chapter 3 First Steps - Porous Media
3-2
1 Click File, Open.
2 In the Open dialog box, browse to the
Catalyst.SLDASM assembly located in
the First Steps - Porous Media folder
and click Open (or double-click the
assembly). Alternatively, you can drag
and drop the Catalyst.SLDASM file to
an empty area of SolidWorks window.
Once inside the Wizard, select Create
new in order to create a new
configuration and name it Isotropic.
The project Wizard guides you through the definition of the project’s properties
step-by-step. Except for two steps (steps to define the project fluids and default solid),
each step has some pre-defined values, so you can either accept these values (skipping
the step by clicking Next) or modify them to your needs.
These pre-defined settings are:
unit system – SI,
analysis type – internal, no additional physical capabilities are considered,
wall condition – adiabatic wall
initial conditions – pressure - 1 atm, temperature - 293.2 K.
result and geometry resolution – level 3,
For this project these default settings suit perfectly and all what we need to do is just to
select Air as the project fluid. To avoid passing through all steps we will use Navigator
pane that provides a quick access to the Wizard’s pages.
2 Click an arrow at the right.
Inlet
Outlet
Porous catalysts

3 In the Navigator pane click
Fluids.
4 Open the Gases folder, click
Air, then click Add.
5 Since we do not need to change other properties we can close the Wizard.
Click Finish in the Navigator pane.
You can click Finish at any moment, but if you attempt to close Wizard without
specifying all obligatory properties (such as project fluds), the Wizard will not close
and the page where you need to define a missing property will be marked by the
exclamation icon .
Now Flow Simulation creates a new configuration with the Flow Simulation data
attached.
In the Flow Simulation Analysis tree, right-click the Computational Domain icon and
select Hide to hide the black wireframe box.

Define the Boundary Conditions
3-4
1 In the Flow Simulation Analysis tree,
right-click the Boundary Conditions icon and
2 Select the inner face of the inlet lid as shown.
3 Select Flow Openings and Inlet Velocity.
4 Set the Velocity Normal to Face to 10 m/s.
5 Click OK .
With the definition just made, we told Flow Simulation
that at this opening air is flowing into the catalyst with a
velocity of 10 m/s.

6 Select the inner face of the outlet lid as shown.
7 Right-click the Boundary Conditions icon and
8 Select Pressure Openings and Static
Pressure.
9 Click OK .
With the definition just made, we told Flow Simulation
that at this opening the fluid exits the model to an area of
static atmospheric pressure.
Now we can specify porous media in this project. To define a porous medium, first we
need to specify the porous medium’s properties (porosity, permeability type, etc.) in the
Engineering Database and then apply the porous medium to a component in the
assembly.
Create an Isotropic Porous Medium
The material you are going to create is already defined in the Engineering Database under
the Pre-Defined folder. You can skip the definition of porous material and select the
pre-defined "Isotropic" material from the Engineering database when you will assign the
porous material to a component later in this tutorial.
2 In the Database tree select Porous Media,
User Defined.
3 Click New Item on the toolbar. The blank Item Properties tab
appears. Double-click the empty cells to set the corresponding
property values.
4 Name the new porous medium Isotropic.
5 Under Comment, click the button and type the desired comments for this porous
medium. The Comment property is optional, you can leave this field blank.

3-6
6 Set the medium’s Porosity to 0.5.
Porosity is the effective porosity of the porous medium, defined as the volume fraction
of the interconnected pores with respect to the total porous medium volume; here, the
porosity is equal to 0.5. The porosity will govern the exhaust flow velocity in the porous
medium channels, which, in turn, governs the exhaust gas residence in the porous
catalyst and, therefore, the catalyst efficiency.
7 Choose Isotropic as the Permeability type.
First of all let us consider an Isotropic permeability, i.e, a medium with permeability
not depending on the direction within the medium. Then, as an alternative, we will
consider a Unidirectional permeability, i.e., the medium permeable in one direction
only.
8 Choose Pressure drop, Flowrate, Dimensions as the Resistance calculation
formula.
For our media we select the Pressure Drop, Flowrate, Dimensions medium
resistance to flow, i.e., specify the porous medium resistance as k = ΔP×S /(m×L) (in
units of s-1), where the right-side parameters are referred to a tested parallelepiped
sample of the porous medium, having the S cross-sectional area and the L length in the
selected sample direction, in which the mass flow rate through the sample is equal to m
under the pressure difference of ΔP between the sample opposite sides in this
direction.
In this project we will specify ΔP = 20 Pa at m = 0.01 kg/s (and ΔP = 0 Pa at
m=0 kg/s), S = 0.01 m2, L = 0.1m. Therefore, k = 200 s-1.
Knowing S and L of the catalyst inserted into the model and m of the flow through it,
you can approximately estimate the pressure loss at the model catalyst from
ΔP = k×m×L/S.
9 For the Pressure drop vs.
flowrate choose Mass Flow
Rate. Click the button to
switch to the Tables and
Curves tab.

10 In the Property table specify the
linear dependency of pressure drop
vs. mass flow rate as shown.
11 Go back to the Item Properties tab.
12 Set Length to 0.1 m and Area to
0.01 m2.
13 Click Save .
14 Click File, Exit to exit the database.
Now we will apply the specified porous
medium to the model components
representing the porous bodies.
A porous medium can be applied only to
a component that is not treated by Flow Simulation as a solid. To consider a model’s
component as not belonging to a solid region, you need to disable the component in the
Component Control dialog box. Components are automatically disabled when you assign
a porous media to them by creating the Porous Medium condition, so you do not need to
disable them manually.
Define the Porous Medium - Isotropic Type
1 Click Flow Simulation, Insert, Porous Medium.
design tree select the
Monolith<1> and Monolith<2>
components.

3-8
3 Expand the list of the User Defined porous media and
select Isotropic. If you skipped the definition of porous
medium, use the Isotropic material available under
Pre-Defined.
4 Click OK to complete the definition of porous
media and exit the Porous Medium dialog.
To obtain the total pressure drop between the model inlet and
outlet we will set an Equation Goal. For this, we need to
specify the corresponding Surface Goals first.
1 Right-click the Goals icon and select Insert Surface
Goals.

and click the Inlet Velocity 1 item to select the
inner face of the inlet lid.
in the Total Pressure row.
4 Accept the selected Use for Conv. (Use for
of the PropertyManager, click Inlet .
6 Click OK - the new
SG Inlet Av Total Pressure 1 goal
appears.
7 Right-click the Goals icon and select Insert Surface Goals.

3-10
and click the Static Pressure 1 item to select
the inner face of the outlet lid.
in the Total Pressure row.
10 Accept the selected Use for Conv. (Use for
of the PropertyManager, click Outlet .
12 Click OK - the new
SG Outlet Av Total Pressure 1 goal
appears.
Define the Equation Goal
Equation Goal is a goal defined by an analytical function of the existing goals and/or
parameters of input data conditions. This goal can be viewed as equation goal during
the calculation and while displaying results in the same way as the other goals. As
variables, you can use any of the specified goals, including another equation goals,
except for goals that are dependent on other equation goals, and parameters of the
specified project’s input data features (general initial or ambient conditions, boundary
conditions, fans, heat sources, local initial conditions). You can also use constants in
the definition of the equation goal.

1 Right-click the Goals icon and select Insert Equation
Goal.
2 In the Flow Simulation Analysis tree select the
SG Inlet Av Total Pressure 1 goal. It appears in the Expression box.
3 Click the minus "-" button in the calculator.
4 In the Flow Simulation Analysis tree select the SG Outlet Av Total Pressure 1 goal.
You can use goals (including previously specified Equation Goals), parameters of
input data conditions and constants in the expression defining an Equation Goal. If the
constants in the expression represent some physical parameters (i.e. length, area, etc.),
make sure that they are specified in the project’s system of units. Flow Simulation has
no information about the physical meaning of the constants you use, so you need to
specify the Equation Goal dimensionality by yourself.
5 Keep the default Pressure & Stress in the Dimensionality list.
6 Click OK. The new Equation Goal 1
item appears in the tree.
Solution
2 Click Run.
After the calculation has finished, close the Monitor
dialog box.

Viewing the Goals
3-12
1 Right-click the Goals icon under Results and select Insert.
2 Select the Equation Goal 1 in the Goals
dialog box.
3 Click OK.
An Excel spreadsheet with the goal results will
open. The first sheet will contain a table
presenting the final values of the goal.
You can see that the total pressure drop is about 120 Pa.
Catalyst.SLDASM [Isotropic]
Equation Goal 1 [Pa] 120.0326909 121.774802 120.0326909 124.432896 100 Yes
To see the non-uniformity of the mass flow rate distribution over a catalyst’s cross section,
we will display flow trajectories with start points distributed uniformly across the inlet.

Flow Trajectories
1 Right-click the Flow Trajectories icon and select
Insert.
2 Click the Flow Simulation Analysis Tree tab and then
click the Inlet Velocity 1 item. This selects the inner
face of the inlet lid.
3 Under Options set Draw Trajectories As to
Bands.

3-14
5 In the View Settings dialog box, change the
Parameter from Pressure to Velocity.
6 Set the Max value to 12.
7 Click OK to save the changes and exit the
View Settings dialog box.
8 In the Flow Trajectories dialog click OK .
To see trajectories inside the porous media we will apply some transparency to the model.
9 Click Flow Simulation, Results, Display, Transparency
and set the model transparency to 0.75.
This is the picture you should see.
To compare the effectiveness of a unidirectional porous catalyst to an isotropic catalyst, let
us calculate the project with a porous medium of unidirectional type.
Clone the Project

2 Enter Unidirectional as the Configuration name.
3 Click OK.
Create a Unidirectional Porous Medium
the Pre-Defined folder. You can skip the definition of porous material and select the
pre-defined "Unidirectional" material from the Engineering database when you will assign
the porous material to a component later in this tutorial.
2 In the Database tree select Porous Media, User Defined.
3 On the Items tab select the Isotropic item.
4 Click Copy .
5 Click Paste . The new Copy of Isotropic (1) item appears in the list.
6 Select the Copy of
Isotropic (1) item and click the
Item Properties tab.
7 Rename the item to
Unidirectional.
8 Change the Permeability type
to Unidirectional.
9 Save the database and exit.
Now we can apply the new porous medium to the monoliths.
Define the Porous Medium - Unidirectional Type
1 Right-click the Porous Medium 1 icon and select Edit Definition.

3-16
2 Expand the list of User Defined porous medium and
select Unidirectional. If you skipped the definition of the
unidirectional porous medium, use the Unidirectional
material available under Pre-Defined.
3 In the Direction select the Z axis of the Global
Coordinate System.
For porous media having unidirectional permeability, we
must specify the permeability direction as an axis of the
selected coordinate system (axis Z of the Global
coordinate system in our case).
4 Click OK .
Since all other conditions and goals remain the same, we can
start the calculation immediately
Compare the Isotropic and Unidirectional Catalysts
When the calculation is finished, create the goal plot for the Equation Goal 1.
Catalyst.SLDASM [Unidirectional]
Equation Goal 1 [Pa] 117.0848512 118.6235708 117.0761518 121.5639633 100 Yes
Display flow trajectories as described above.
Comparing the trajectories passing through the isotropic and unidirectional porous
catalysts installed in the tube, we can summarize:

Due to the asymmetric position of the inlet tube with respect to the larger tube in which
the catalyst bodies are installed, the incoming flow is non-uniform. Since the incoming
flow is non-uniform, the flow inside the first catalyst body is non-uniform also. It is seen
that the catalyst type (isotropic or unidirectional) affects both the incoming flow
non-uniformity (slightly) and, more substantially, the flow within the catalysts (especially
the first catalyst body). In both the cases the gas stream mainly enters the first catalyst
body-closer to the wall opposite to the inlet tube. For the isotropic case, the gas flows into
the first body nearer to the wall than for the case of the unidirectional catalyst. As a result,
the flow in the initial (about one-third of the body length) portion of the first catalyst body
is noticeably more non-uniform in the isotropic catalyst. Nevertheless, due to the isotropic
permeability, the main gas stream expands in the isotropic catalyst and occupies a larger
volume in the next part of the body than in the unidirectional catalyst, which, due to its
unidirectional permeability, prevents the stream from expanding. So, the flow in the last
two-thirds of the first catalyst body is less non-uniform in the isotropic catalyst. Since the
distance between the two porous bodies installed in the tube is rather small, the gas stream
has no time to become more uniform in the volume between the catalyst bodies, although
in the unidirectional case a certain motion towards uniformity is perceptible. As a result,
the flow non-uniformity occurring at the first catalyst body's exit passes to the second
catalyst body. Then, it is seen that the flow non-uniformity does not change within the
second catalyst body.
Let us now consider the flow velocity inside the catalyst. This is easy to do since the flow
trajectories' colors indicate the flow velocity value in accordance with the specified
palette. To create the same conditions for comparing the flow velocities in the isotropic
and unidirectional catalysts, we have to specify the same velocity range for the palette in
both the cases, since the maximum flow velocity governing the value range for the palette
by default is somewhat different in these cases. It is seen that, considering the catalyst on
the whole, the flow velocities in the isotropic and unidirectional catalysts are practically
the same. Therefore, from the viewpoint of gas residence in the catalyst, there is no
difference between the isotropic and unidirectional catalysts.
We can conclude that the isotropic catalyst is more effective than the unidirectional
catalyst (of the same resistance to uniform flows), since the flow in it, as a whole, is more
uniform. In spite of specifying the same resistance of the catalysts to flow, the overall
pressure loss is lower by about 2% in the case of employing the unidirectional catalyst.
This difference is due to the different flow non-uniformity both in the catalyst bodies and
out of them.

3-18

4
In engineering practice the hydraulic loss of pressure head in any piping system is
traditionally split into two components: the loss due to friction along straight pipe sections
and the local loss due to local pipe features, such as bends, T-pipes, various cocks, valves,
throttles, etc. Being determined, these losses are summed to form the total hydraulic loss.
Generally, there are no problems in engineering practice to determine the friction loss in a
piping system since relatively simple formulae based on theoretical and experimental
investigations exist. The other matter is the local hydraulic loss (or so-called local drag).
Here usually only experimental data are available, which are always restricted due to their
nature, especially taking into account the wide variety of pipe shapes (not only existing,
but also advanced) and devices, as well as the substantially complicated flow patterns in
them. Flow Simulation presents an alternative approach to the traditional problems
associated with determining this kind of local drag, allowing you to predict
computationally almost any local drag in a piping system within good accuracy.
Click File, Open. In the Open dialog box, browse to the Valve.SLDPRT model located in
the Tutorial 1 - Hydraulic Loss folder and click Open (or double-click the part).
Alternatively, you can drag and drop the Valve.SLDPRT file to an empty area of the
SolidWorks window.

Chapter 4 Determination of Hydraulic Loss
Model Description
4-2
This is a ball valve. Turning the handle closes or
opens the valve.
The local hydraulic loss (or drag) produced by a ball
valve installed in a piping system depends on the
valve turning angle or on the minimum flow passage
area governed by it. The latter depends also on a ball
valve geometrical parameter, which is the ball-to-pipe
diameter ratio governing the handle angle at which
the valve becomes closed:
= sin 
θ arc 2
Dball
Dpipe
 -------------
The standard engineering convention for determining local drag is by calculating the
difference between the fluid dynamic heads measured upstream of the local pipe feature
(ball valve in our case) and far downstream of it, where the flow has become uniform
(undisturbed) again. In order to extract the pure local drag the hydraulic friction loss in the
straight pipe of the same length must be subtracted from the measured dynamic head loss.
In this example we will obtain pressure loss (local drag) in the ball valve whose handle is
turned by an angle of 40o. The Valve analysis represents a typical Flow Simulation internal
analysis.
Internal flow analyses deal with flows inside pipes, tanks, HVAC systems, etc. The fluid
enters a model at the inlets and exits the model through outlets.
To perform an internal analysis all the model openings must be closed with lids, which are
needed to specify inlet and outlet flow boundary conditions on them. In any case, the
internal model space filled with a fluid must be fully closed. You simply create lids as
additional extrusions covering the openings. In this example the lids are semi-transparent
allowing a view into the valve.

To ensure the model is fully closed click Flow Simulation, Tools,
Check Geometry. Then click Check to calculate the fluid and
solid volumes of the model. If the fluid volume is equal to zero, the
model is not closed.
Click Fluid Volume to see the volume that will be occupied by
fluid in the analysis.
Uncheck Fluid Volume. Close the Check Geometry dialog box.
The Check Geometry tool allows you to calculate the total fluid
and solid volumes, check bodies for possible geometry
problems (i.e. invalid contact) and visualize the fluid area and
solid body as separate models.
The first step is to create a new Flow Simulation project.
Creating a Project
1 Click Flow Simulation, Project, Wizard. The project wizard guides you through the
definition of a new Flow Simulation project.
2 In the Project Configuration dialog box,
click Use current. Each Flow Simulation
project is associated with a SolidWorks
configuration. You can attach the project
either to the current SolidWorks
configuration or create a new SolidWorks
configuration based on the current one.
Click Next.
3 In the Unit System dialog box you can
select the desired system of units for both
input and output (results).
For this project use the International
System SI by default.
Click Next.

4-4
4 In the Analysis Type dialog box you can
select either Internal or External type of
the flow analysis.
To disregard closed internal spaces not
involved in the internal analysis, you
select Exclude cavities without flow
conditions.
The Reference axis of the global
coordinate system (X, Y or Z) is used
for specifying data in a tabular or
formula form in a cylindrical coordinate
system based on this axis.
This dialog also allows you to specify advanced physical features you may want to take
into account (heat conduction in solids, gravitational effects, time-dependent problems,
surface-to-surface radiation, rotation).
Specify Internal type and accept the other default settings.
Click Next.
5 Since we use water in this project, open
the Liquids folder and double-click the
Water item.
Engineering Database contains
numerical physical information on a wide variety of gas, liquid and solid substances as
well as radiative surfaces. You can also use the Engineering Database to specify a
porous medium. The Engineering Database contains pre-defined unit systems. It also
contains fan curves defining volume or mass flow rate versus static pressure difference
for selected industrial fans. You can easily create your own substances, units, fan
curves or specify a custom parameter you want to visualize.
Click Next.

6 Since we do not intend to calculate heat
conduction in solids, in the Wall
Conditions dialog box you can specify
the thermal wall boundary conditions
applied by default to all the model walls
contacting with the fluid.
For this project accept the default
Adiabatic wall feature denoting that all
the model walls are heat-insulated.
In this project we will not consider rough
walls.
Click Next.
7 In the Initial Conditions dialog box specify
initial values of the flow parameters. For
steady internal problems, the specification of
these values closer to the expected flow field
will reduce the analysis convergence time.
For steady flow problems Flow Simulation
iterates until the solution converges. For unsteady (transient, or time-dependent)
problems Flow Simulation marches in time for a period you specify.
For this project use the default values.
Click Next.
8 In the Results and Geometry Resolution
dialog box you can control the analysis
accuracy as well as the mesh settings and,
through them, the required computer
resources (CPU time and memory).
For this project accept the default result
resolution level 3.
Result Resolution governs the solution accuracy via mesh settings and conditions of
finishing the calculation that can be interpreted as resolution of calculation results.
The higher the Result Resolution, the finer the mesh and the stricter the convergence
criteria. Naturally, higher Result Resolution requires more computer resources (CPU
time and memory).

4-6
Geometry Resolution (specified through the minimum gap size and the minimum wall
thickness) governs proper resolution of geometrical model features by the
computational mesh. Naturally, finer Geometry Resolution requires more computer
resources.
Select the Manual specification of the minimum
gap size check box and enter 0.04 m for the
Minimum gap size.
Flow Simulation calculates the default minimum gap
size and minimum wall thickness using information
about the overall model dimensions, the
computational domain, and faces on which you
specify conditions and goals. However, this
information may be insufficient to recognize
relatively small gaps and thin model walls. This may
cause inaccurate results. In these cases, the
Minimum gap size and Minimum wall thickness must
be specified manually.
Click Finish.
The Flow Simulation Analysis tree provides a convenient specification of project
data and view of results. You also can use the Flow Simulation Analysis tree to modify
or delete the various Flow Simulation features.
At the same time, a computational domain appears in the SolidWorks graphics area as a
wireframe box.
The Computational Domain is a rectangular
prism embracing the area inside which the flow
and heat transfer calculations are performed.
The next step is specifying Boundary Conditions. Boundary Conditions are used to
specify fluid characteristics at the model inlets and outlets in an internal flow analysis or
on model surfaces in an external flow analysis.

Specifying Boundary Conditions
1 Click Flow Simulation, Insert, Boundary Condition.
2 Select the Inlet Lid inner face (in contact with the fluid).
The selected face appears in the Faces to Apply the
Boundary Condition list.
3 In the Type of Boundary Condition list, select the Inlet
Velocity item.
4 Click the Velocity Normal to Face box and set its
value equal to 1 m/s (type the value, the units will
appear automatically).
5 Accept all the other parameters and click OK .
This simulates the water flow which enters the valve with the velocity of 1.0 m/s.
6 Select the Outlet Lid inner face.
7 In the graphics area, right-click outside
the model and select Insert Boundary
Condition. The Boundary Condition
dialog box appears with the selected
face in the Faces to apply the
boundary condition list.
Before the calculation starts, Flow
Simulation checks the specified
boundary conditions for mass flow rate
balance. The specification of boundary conditions is incorrect if the total mass flow
rate on the inlets is not equal to the total mass flow rate on the outlets. In such case the
calculation will not start. Also, note that the mass flow rate value is recalculated from
the velocity or volume flow rate value specified on an opening. To avoid problems with

4-8
specifying boundary conditions, we recommend that you specify at least one Pressure
opening condition since the mass flow rate on a Pressure opening is automatically
calculated to satisfy the law of conservation of mass.
8 Click Pressure Openings and in the Type of
Boundary Condition list select the Static Pressure
item.
9 Accept the default values for Static Pressure
(101325 Pa), Temperature (293.2 K) and all the other
parameters.
10 Click OK .
By specifying this condition we define that at the ball valve pipe exit the water has a static
pressure of 1 atm.
The hydraulic losses are calculated through the outlet and inlet total pressure difference
ΔP from the following formula:
ξ ΔP
= -----------------
ρV2 ⁄ 2
where ρ is the water density, and V is water velocity. Since we already know the water
velocity (specified by us as 1 m/s) and the water density (998.1934 kg/m3 for the specified
temperature of 293.2 K), then our goal is to determine the total pressure value at the
valve’s inlet and outlet. The easiest and fastest way to find the parameter of interest is to
specify the corresponding engineering goal.
1 In the Flow Simulation Analysis tree, right-click the
Goals icon and select Insert Surface Goals.
2 Select the inner faces of the inlet lid and the outlet lid.

3 Select Create a separate goal for each surface
check box to create two separate goals, i.e. one
for each of the selected faces.
4 In the Parameter table select the Av check box in
the Total Pressure row.
5 Accept selected Use for Conv. check box to use
the goals being created for convergence control.
6 Click OK . The new SG Av Total Pressure 1
and SG Av Total Pressure 2 items appear in the
Flow Simulation Analysis tree.
Now the Flow Simulation project is ready for the
calculation. Flow Simulation will finish the
calculation when the steady-state average value of total pressure calculated at the valve
inlet and outlet are reached.
Running the Calculation
1 Click Flow Simulation, Solve, Run. The Run dialog box appears.
2 Click Run to start the calculation.
Flow Simulation automatically
generates a computational mesh. The
mesh is created by dividing the
computational domain into slices,
which are further subdivided into cells.
The cells are refined as necessary to
properly resolve the model geometry.
During the mesh generation procedure,
you can see the current step and the
mesh information in the Mesh
Generation dialog box.

Monitoring the Calculation
4-10
After the calculation starts, the Solver
Monitor dialog provides you with the
current status of the solution. You can
also monitor the goal changes and view
preliminary results at selected planes.
In the bottom pane of the Info window
Flow Simulation notifies you if
inappropriate results may occur. In our
case, the message “A vortex crosses
the pressure opening” appears to
inform you that there is a vortex
crossing the opening surface at which
you specified the pressure boundary
condition. In this case the vortex is broken into incoming and outgoing flow components.
When flow both enters and exits an opening, the accuracy of the results is diminished.
Moreover, there is no guarantee that convergence (i.e., the steady state goal) will be
attained at all. Anyway, in case a vortex crosses a pressure opening the obtained results
become suspect. If this warning persists we should stop the calculation and lengthen the
ball valve outlet pipe to provide more space for development of the vortex. It is also
expedient to attach the ball valve inlet pipe to avoid the flow disturbance caused by the
valve’s obstacle to affect the inlet boundary condition parameters.
Since the warning persists, click File, Close to terminate the calculation and exit the
Solver Monitor.
You can easily extend the ball valve inlet and outlet sections by changing the offset
distance for the Inlet Plane and Outlet Plane features. Instead, we shall clone the project
to the pre-defined 40 degrees - long valve configuration.
Cloning the Project
2 Click Add to existing.
3 In the Existing configuration list, select 40 degrees -
long valve.
4 Click OK.
5 Flow Simulation has detected that the model was
modified. Confirm the both warning messages with Yes.
The new Flow Simulation project, attached to the 40 degrees - long valve configuration,
has the same settings as the old one attached to the 40 degrees - short valve so you can
start the calculation immediately.

In the Flow Simulation analysis tree, right-click the root
40 degrees - long valve item and select Run. Then click
Run to start the calculation.
When the calculation is finished, close the Solver
Monitor dialog box.
Let us now see the vortex notified by Flow Simulation
during the calculation, as well as the total pressure loss.
Creating a Cut Plot
1 Right-click the Cut Plots icon and select Insert. The
Cut Plot dialog box appears.
The Cut Plot displays results of a selected parameter in a selected view section. To
define the view section, you can use SolidWorks planes or model planar faces (with the
additional shift if necessary). The parameter values can be represented as a contour
plot, as isolines, as vectors, or in a combination (e.g. contours with overlaid vectors).
2 In the flyout FeatureManager design
tree, expand the Valve item and select
Plane2. Its name appears in the Section
Plane or Planar Face list.
3 In the Cut Plot dialog box, in addition to
displaying Contours , select
Vectors .
4 In the Vectors group box, using the
slider set the Vector Spacing to approximately 0.012.

4-12
5 Click View Settings to specify the parameter which values to show at the contour plot.
The settings made in the View Settings dialog box refer to all Cut Plots, Surface
Plots, Isosurfaces, and Flow Trajectories features. These settings are applied only for
the active pane of the SolidWorks graphics area. For example, the contours in all cut
and surface plots will show the same physical parameter selected in the View Settings
dialog box. So, in the View Settings dialog box you specify the displayed physical
parameter and the settings required for displaying it for each of the displaying options
(contours, isolines, vectors, flow trajectories, isosurfaces) . The Contours settings can
also be applied to Isolines, Vectors, Flow Trajectories, and Isosurfaces. If the Use
from contours option is selected on the corresponding feature tab, the isolines,
vectors, trajectories, isosurfaces are colored in accordance with values of the
parameter selected on the Contours tab (in this case the color settings made in the
specific dialog boxes are not used).
6 On the Contours tab, in the Parameter box,
select X-velocity.
7 Click OK to save changes and exit the View
Settings dialog box.
8 In the Cut Plot dialog box click OK .
The new Cut Plot 1 item appears in the Flow Simulation Analysis tree.
However, the cut plot cannot be seen through the model. In order to see the plot, you can
hide the model by clicking Flow Simulation, Results, Display, Geometry. Alternatively,
you can use the standard SolidWorks Section View option.
9 Click View, Display, Section View. Under Section 1
specify Plane2 as a Reference Section Plane/Face and
click OK .
10 In the Flow Simulation Analysis tree, right-click the
Computational Domain icon and select Hide.

Now you can see a contour plot of the velocity and the velocity vectors projected on the plot.
For better visualization of the vortex you can scale small vectors:
11 In the Flow Simulation Analysis tree, right-click
the Results icon and select View Settings.
12 In the View Settings dialog, click the
Vectors tab and type 0.02 m the Arrow
size box.
13 Change the Min value to 2 m/s.
By specifying the custom Min we change the vector length range so that the vectors in
areas where velocity is less than the specified Min value will appear as if it is equal to
Min. This allows us to visualize the low velocity area in more detail.
14 Click OK to save the changes and exit the View Settings dialog box. Immediately the
cut plot is updated.

4-14
You can easily visualize the vortex by displaying the flow relative to the X axis. For that,
you can display the X-velocity component in a two-color palette and set the value,
separating two colors, at zero.
15 In the Flow Simulation Analysis tree, right-click the Results icon and select View
Settings.
16 Using the slider set Number of colors to 2.
17 In the Min box type -1.
18 In the Max box type 1.
19 Click OK.
Now the distribution of the X-Velocity
component is displayed in red-blue palette so that all the positive values are in red and all
the negative values are in blue. This means that the blue area show the region of reverse
flow, i.e. half of the vortex.
Next, we will display the distribution of total pressure within the valve.
Working with Parameter List
By default the total pressure is not included in the list of parameters available to display.
To enable or disable a physical parameter for displaying you can use Parameter List.
1 In the Analysis tree, right-click the Results
icon and select Parameter List. Select the
Total Pressure check box or select
parameter’s row and click Enable.
2 Click OK to close the Display Parameters
dialog box.
Now you can apply the total pressure for the
contour plot.

1 Double-click the palette bar in the upper left corner of the graphics area to
open the View Settings dialog box.
2 On the Contours tab, in the
Parameter list select Total
Pressure.
3 Using the slider, set the Number
of colors to about 30.
4 Click OK to save the changes and
exit the View Settings dialog box.
Immediately the cut plot is updated to
display the total pressure contour plot.
The cut plot shows you the flow pattern. To obtain the exact value of the total pressure
which is required to calculate the loss, we will use the surface goal plot.
Creating a Goal Plot
The Goal Plot allows you to study how the goal value changed in the course of
calculation. Flow Simulation uses Microsoft Excel to display goal plot data. Each goal
plot is displayed in a separate sheet. The converged values of all project goals are
displayed in the Summary sheet of an automatically created Excel workbook.
Click View, Display, Section View to hide the section.
1 In the Flow Simulation Analysis tree, under Results, right-click
the Goals icon and select Insert. The Goals dialog
box appears.

4-16
2 Click Add All.
3 Click OK. The goals1 Excel workbook is
created.
This workbook displays how the goal changed
during the calculation. You can take the total
pressure value presented at the Summary sheet.
Valve.SLDPRT [40 degrees - long valve]
SG Av Total Pressure 1 [Pa] 101833.4184 101833.8984 101833.3951 101834.7911 100 Yes
SG Av Total Pressure 2 [Pa] 111386.6792 111389.5793 111384.8369 111399.0657 100 Yes
In fact, to obtain the pressure loss it would be easier to specify an Equation goal with the
difference between the inlet and outlet pressures as the equation goal’s expression.
However, to demonstrate the wide capabilities of Flow Simulation, we will calculate the
pressure loss with the Flow Simulation gasdynamic Calculator.
The Calculator contains various formulae from fluid dynamics which can be useful for
engineering calculations. The calculator is a very useful tool for rough estimations of
the expected results, as well as for calculations of important characteristic and
reference values. All calculations in the Calculator are performed only in the
International system of units SI, so no parameter units should be entered, and Flow
Simulation Units settings do not apply in the Calculator.
Working with Calculator
1 Click Flow Simulation, Tools, Calculator.
2 Right-click the A1 cell in the Calculator sheet
and select New Formula. The New Formula
dialog box appears.
3 In the Select the name of the new formula tree
expand the Pressure and Temperature item
and select the Total pressure loss check box.

4 Click OK. The total pressure loss formula
appears in the Calculator sheet.
In the Result (or A) column you see the formula
name, in the next columns (B, C, etc.) you see
names of the formula arguments (variables and
constants). You can either type all the formula
arguments’ values in cells under their names in
the SI units, or copy and paste them from the
goals Excel worksheet table obtained through the
Goals dialog box. The result value appears in the
Result column cell immediately when you enter
all the arguments and click another cell.
5 Specify the values in the cells as follows:
Density = 998.1934 (the water density for the
specified temperature of 293.2 K),
Velocity = 1.
6 Open the goals1 Excel workbook and copy the Value of SG Av Total Pressure 1 into
the Clipboard.
7 Go to the Calculator, click the B2 cell and press Ctrl+V to paste the goal value from
the Clipboard.
8 Return to Excel, copy the Value of SG Av Total Pressure 2. Go to the Calculator,
click the C2 cell and press Ctrl+V. Click any free cell. Immediately the Total pressure
loss value appears in the Result column.
9 Click File, Save.
10 In the Save As dialog box browse to the folder where the ball valve model used in this
example is located, enter ball valve for the file name, and click Save.
11 Click File, Exit to exit the Calculator.
To obtain the pure local drag, it is necessary to subtract from the obtained value the total
pressure loss due to friction in a straight pipe of the same length and diameter. To do that,
we perform the same calculations in the ball valve model with the handle in the 0o angle
position. You can do this with the 00 degrees - long valve configuration.

4-18
Since the specified conditions are the same for both 40 degrees - long valve and 00
degrees - long valve configurations, it is useful to attach the existing Flow Simulation
project to the 00 degrees - long valve configuration.
Clone the current project to the 00 degrees - long valve
configuration.
Since at zero angle the ball valve becomes a simple straight pipe, there is no need to set the
Minimum gap size value smaller than the default gap size which, in our case, is
automatically set equal to the pipe’s diameter (the automatic minimum gap size depends
on the characteristic size of the faces on which the boundary conditions are set). Note that
using a smaller gap size will result in a finer mesh and, in turn, more computer time and
memory will be required for calculation. To solve your task in the most effective way you
should choose the optimal settings for the task.
Changing the Geometry Resolution
Check to see that the 00 degrees - long valve is the active configuration.
2 Clear the Manual specification of
the minimum gap size check box.
3 Click OK.
Click Flow Simulation, Solve, Run.
Then click Run to start the calculation.
After the calculation is finished, create
the Goal Plot. The goals2 workbook is
created. Go to Excel, then select the both
cells in the Value column and copy them
into the Clipboard.
Goal Name Unit Value Averaged Value Minimum Value
SG Av Total Pressure 1 [Pa] 101805.2057 101804.8525 101801.4794
SG Av Total Pressure 2 [Pa] 102023.7419 102054.9498 102022.7459

Now you can calculate the total pressure loss in a straight pipe.
1 Click Flow Simulation, Tools, Calculator.
2 In the Calculator menu, click File, Open. Browse to the folder where you saved the
calculator file earlier in this tutorial and select the ball valve.fwc file. Click Open.
3 Click the B4 cell and in the Calculator toolbar click to paste data from the
Clipboard.
4 Save the existing value of the total pressure loss: click the A2 cell, click , then click
the A7 cell and finally click .
5 Double-click the Name7
cell and type 40 degrees.
6 Right-click the Total
pressure at point 1 cell and select Add
Relation. The cursor appears.
7 Click the B4 cell. The value of total pressure is
now taken from the B4 cell.
8 Right-click the Total pressure at point 2 cell and select Add
Relation.
9 Click the B5 cell. The value of total pressure is now taken from the
B5 cell. Immediately the total pressure value is recalculated.

4-20
Now you can calculate the local drag in the ball valve whose handle is set at 40o.
Total Pressure loss (40 deg) Total Pressure loss (0 deg) Local Drag
19.14 0.44 18.70

5
Flow Simulation can be used to study flow around objects and to determine the resulting
lift and drag forces on the objects due to the flow. In this example we use Flow Simulation
to determine the drag coefficient of a circular cylinder immersed in a uniform fluid
stream. The cylinder axis is oriented perpendicular to the stream.
The computations are performed for a range of Reynolds numbers (1,1000,105), where
, D is the cylinder diameter, U is the velocity of the fluid stream, ρ is the
Re ρUD
= ------μ----------
density, and μ is the dynamic viscosity. The drag coefficient for the cylinder is defined as:
CD
FD
= ----------------------
1
2
--ρU
2
DL
where FD is the total force in the flow direction (i.e. drag) acting on a cylinder of diameter
D and length L.
The goal of the simulation is to obtain the drag coefficient predicted by Flow Simulation
and to compare it to the experimental data presented in Ref.1.

Chapter 5 Cylinder Drag Coefficient
5-2
Click File, Open. In the Open dialog box, browse to the Cylinder 0.01m.SLDPRT part
located in the Tutorial 2 - Drag Coefficientcylinder 0.01m folder and click Open (or
double-click the part). Alternatively, you can drag and drop the cylinder 0.01m.SLDPRT
file to an empty area of SolidWorks window.
The Cylinder analysis represents a typical Flow Simulation External analysis.
External flows analyses deal with flows over or around a model such as flows over
aircrafts, automobiles, buildings, etc. For external flow analyses the far-field
boundaries are the Computational Domain boundaries. You can also solve a combined
external and internal flow problem in a Flow Simulation project (for example flow
around and through a building). If the analysis includes a combination of internal and
external flows, you must specify External type for the analysis.
The first step is to create a new Flow Simulation project.
Creating a Project
1 Click Flow Simulation, Project, Wizard. The project wizard guides you through the
definition of a new Flow Simulation project. In this project we will analyze flow over
the cylinder at the Reynolds number of 1.
2 Select Create new. In the Configuration
name box type Re 1. This is the name of
the SolidWorks configuration that will be
created for the associated Flow
Simulation project.
Click Next.

3 In the Unit System dialog box you can
select the desired system of units for both
input and output (results).
In this project we will specify the
International System SI by default.
Click Next.
4 In the Analysis Type dialog box select an
External type of flow analysis. This dialog
also allows you to specify advanced
physical features you want to include in
the analysis. In this project we will not use
any of the advanced physical features
To disregard closed internal spaces within the body you can select Exclude internal
spaces; however no internal spaces exist within the cylinder in this tutorial. The
Reference axis of the global coordinate system (X, Y or Z) is used for specifying data
in a tabular or formula form with respect to a cylindrical coordinate system based on
this axis.
The flow over a cylinder is steady at a Reynolds number Re < 40 (see the cylinder Re
definition above) and unsteady (time-dependent) at Re > 40. Since in this tutorial the
first calculation is performed at Re=1, to accelerate the run, we perform a steady-state
analysis.
Click Next.
5 Since we use water in this project, open
the Liquids folder and double-click the
Water item.
Click Next.

5-4
6 In the Wall Conditions dialog box you
may specify the default thermal wall
conditions applied to all the model walls in
contact with the fluid.
In this project we keep the default
Adiabatic wall setting, denoting that all the
model walls are heat-insulated and accept
the default zero wall roughness.
Click Next.
For a steady External problem, such as the
cylinder in this tutorial, the Initial and Ambient Conditions dialog box asks you to
specify the ambient flow conditions of the undisturbed free stream. Thus you will
specify initial conditions inside the Computational Domain and boundary conditions
at the Computational Domain boundaries. The ambient conditions are
thermodynamic (static pressure and temperature by default), velocity, and turbulence
parameters.
In this project we consider the flow under the default thermodynamic conditions (i.e.,
the standard atmosphere at sea level), and set the incoming stream (X-component)
velocity in accordance with the desired Reynolds number.
For convenience we can use the
Dependency box to specify the incoming
flow velocity in terms of the Reynolds
number.
7 Click in the Velocity in X direction field.
The Dependency button is enabled.
8 Click Dependency. The Dependency
dialog box appears.
Using Dependency you can specify data in several ways: as a constant, as a tabular or
formula dependency on x, y, z, r, θ, ϕ coordinates and time t (only for time-dependent
analysis). The radius r is the distance from a point to the Reference axis selected from
the reference coordinate system (the Global Coordinate System for all data set in the
Wizard and General Settings dialog boxes), while θ and ϕ are the polar and
azimuthal angles of spherical coordinate system, respectively. Therefore, by
combination of r, θ, and ϕ coordinates you can specify data in cylindrical or spherical
coordinate systems.
9 In the Dependency type list select Formula Definition.

10 In the Formula box type the formula defining the flow
velocity using the Reynolds number:
1*(0.0010115/0.01/998.19). Here:
1 – the Reynolds number (Re)
0.0010115 (Pa*s) - the water dynamic viscosity (μ) at the
specified temperature of 293.2 K
0.01 (m) - the cylinder diameter (D)
998.19 (kg/m3)- the water density (ρ) at the specified
temperature of 293.2 K
11 Click OK. You will return to the Initial and Ambient
Conditions dialog box.
For most flows it is difficult to have a good estimation of their turbulence a priori, so it
is recommended that the default turbulence parameters be used. The default turbulence
intensity values proposed by Flow Simulation are 0.1% for external analyses and 2%
for internal analyses and these values are appropriate for most cases. In this project we
will specify a turbulence intensity of 1%.
12 Expand the Turbulence parameters item
and in the Turbulence intensity box
type 1.
Click Next.
13 In the Result and Geometry Resolution
dialog box specify the result resolution
level of 7 and accept the automatically
defined minimum gap size and minimum
wall thickness.
Click Finish. The project is created and
the 3D Computational Domain is
automatically generated.
In this tutorial we are interested in determining the drag coefficient of the cylinder only,
without the accompanying 3D effects. Thus, to reduce the required CPU time and
computer memory, we will perform a two-dimensional (2D) analysis in this tutorial.

Specifying 2D Plane Flow
5-6
1 In the Flow Simulation Analysis tree, expand the Input Data item.
2 Right-click the Computational Domain icon and
select Edit Definition. The Computational Domain
dialog box appears.
3 Click the Boundary Condition tab.
4 In the 2D plane flow list select XY-Plane Flow
(since the Z-axis is the cylinder axis).
Automatically the Symmetry condition is
specified at the Z min and Z max boundaries of
the Computational Domain.
Click the Size tab. You can see that the Z min and
Z max boundaries are set automatically, basing on
the model dimensions.
Thus the reference cylinder length L in the cylinder drag (CD) formula presented above
is equal to L = Z max-Z min = 0.002 m.
For most cases, to study the flow field around an external body and to investigate the
effects of design changes it is recommended to use the default Computational Domain
size as determined by Flow Simulation. However, in this case we will compare the
Flow Simulation results to experimental results and we would like to determine the
drag coefficient with a high degree of accuracy. In order to eliminate any disturbances
of the incoming flow at the Computational Domain boundaries due to the presence of
the cylinder, we will manually set the boundaries farther away from the cylinder. The
accuracy will be increased at the expense of required CPU time and memory due to the
larger size of Computational Domain.
5 Specify the coordinates of the
Computational domain boundaries as
shown on the picture to the right.
6 Click OK.
Since the incoming flow is aligned with the
X-axis direction, the cylinder drag
coefficient is calculated through the
X-component of the force acting on the
cylinder.
The X-component of force can be determined easily by specifying the appropriate Flow
Simulation goal. For this case you will specify the X - Component of Force as a Global
Goal. This ensures that the calculation will not be finished until X - Component of Force
in the entire computational domain (i.e. on the cylinder surface) is fully converged.

Specifying a Global Goal
1 Click Flow Simulation, Insert, Global Goals.
2 In the Parameter table select the first
check box in the X - Component of
Force row.
3 Accept selected Use for Conv. check box
to use this goal for convergence control.
For the X(Y, Z) - Component of Force
and X(Y, Z) - Component of Torque goals
you can select the Coordinate system in
which these goals are calculated. In this
example the default Global Coordinate
System meets the task.
4 Click OK . The new GG X - Component of
Force 1 item appears in the Flow Simulation
Analysis tree.
Specifying an Equation Goal
When the calculation is finished, you will need to manually calculate the drag coefficient
from the obtained force value. Instead, let Flow Simulation to make all the necessary
calculations for you by specifying an Equation Goal.
1 Click Flow Simulation, Insert,
Equation Goal.
2 In the Flow Simulation Analysis tree
select the GG X - Component of
Force 1 goal. It appears in the
Expression box.
3 Use buttons in the calculator or keyboard to complete the expression as follows:
{GG X - Component of Force 1}/(0.002*(1*0.0010115)^2)*(2*998.19*0.01).

5-8
4 Select No units in the Dimensionality list and click OK. The new Equation Goal 1 item
5 Rename the Equation Goal 1 to Drag Coefficient.
To compare the Flow Simulation results with the experimental curve taken from Ref.1, we
will obtain the results at a Reynolds number of 1, 103 and 105. As with Re = 1, the
Cylinder 0.01m.SLDPRT is used to calculate the flow at the Reynolds number of 103.
The Cylinder 1m.SLDPRT is used to calculate the flow at the Reynolds number of 105.
Cloning a Project and Creating a New Configuration
1 In the Flow Simulation Analysis tree, right-click the top
Re 1 icon and select Clone Project.
2 In the Configuration name box, type Re 1000.
3 Click OK. The new Re 1000 configuration is
created with the Flow Simulation project
attached.
Since the new project is a copy of the Re 1 Flow Simulation project, you only need to
change the flow velocity value in accordance with the Reynolds number of 1000. Use
the General Settings dialog box to change the data specified in the Wizard, except the
settings for Units and Result and Geometry Resolution.
The General Settings always presents the current state of the project parameters. You
can change General Settings to correct the settings made in the Wizard or to modify
the project created with the Flow Simulation Template in accordance with the new
project requirements.

Changing Project Settings
1 Click Flow Simulation, General Settings. The General Settings dialog box appears.
2 As it has been mentioned above, since
the flow over a cylinder is unsteady at
Re > 40, select the Time-dependent
physical feature for this project.
3 In the Navigator click Initial and
ambient conditions.
4 Click the Velocity in X direction field
and then click Dependency.

5-10
5 In the Formula box, type the formula for the new Reynolds
number:
1e3*(0.0010115/0.01/998.19).
6 Click OK to return to the General Settings dialog box.
7 Click OK to save changes and close the General Settings
dialog box.
Changing the Equation Goal
1 Right-click the Drag Coefficient icon under Goals and select Edit Definition.
2 In the Expression box type the new formula for the new Reynolds number:
{GG X - Component of Force 1}/(0.002*(0.0010115*10^3)^2)*(2*998.19*0.01).
3 Select No units in the Dimensionality list.
4 Click OK to save changes and close the Equation Goal dialog box.
In the experiments performed with one fluid medium, the Reynolds number’s large rise is
usually obtained by increasing both the velocity and the model overall dimension (i.e.
cylinder diameter) since it is difficult to increase only velocity by e.g. 105 times. Since our
simulation is performed with water only, let us increase the cylinder diameter to 1 m to
perform the calculation at a Reynolds number of 105.
Cloning a project is convenient if you want to create similar projects for the same model.
The easiest way to apply the same general project settings to another model is to use the
Flow Simulation Template.
Template contains all of the general project settings that can be used as a basis for a
new project. These settings are: problem type, physical features, fluids, solids, initial
and ambient flow parameters, wall heat condition, geometry and result resolution, and
unit settings. Notice that Boundary Conditions, Fans, Initial Conditions, Goals and
other features accessible from the Flow Simulation, Insert menu, as well as results are
not stored in the template. Initially, only the New Project default template is available,
but you can easily create your own templates.

Creating a Template
1 Click Flow Simulation, Project, Create Template.
The Create Template dialog box appears.
2 In the Template name box, type Cylinder Drag.
3 Click Save. The new Flow Simulation template is
created.
All templates are stored as .fwp files in the <install_dir>/Template folder, so you can
easily apply a template to any previously created models.
4 Save the model.
Next, create a new project based on the Cylinder Drag template.
Creating a Project from the Template
Open the Cylinder 1m.SLDPRT file located in the cylinder 1m folder.
1 Click Flow Simulation, Project, New. The New Flow
Simulation Project dialog box appears.
2 In the Configuration name box, type Re 1e5.
3 In the List of templates, select Cylinder Drag.
4 Click OK.
The newly created project has the same settings as the Re 1000 project with the cylinder
0.01m model. The only exceptions are Geometry Resolution and Computational
Domain size, which are calculated by Flow Simulation in accordance with the new model
geometry.
Notice that the 2D plane flow setting and Global Goal are retained. Next, you can modify
the project in accordance with the new model geometry.

5-12
1 Click Flow Simulation, Computational
Domain and adjust the computational
domain size as shown at the picture to
the right.
2 Click OK.
3 Open the General Settings dialog box
and click Initial and ambient
conditions, click the Velocity in X
direction field, then click Dependency.
4 Change the velocity X component
formula as follows:
1e5*(0.0010115/1/998.19).
Click OK to return to the General Settings dialog box.
By default, Flow Simulation determines the default
turbulence length basis equal to one percent of the model
overall dimension (i.e. cylinder diameter). Since the Re 1e5
project was created from the template, it inherited the
turbulence length value calculated for the small cylinder (d = 0.01m). For the cylinder
1m we need to change this value.
5 In the General Settings dialog box
expand the Turbulence parameters
item. Type 0.01 m in the Turbulence
length field.
6 Click OK.
7 Create the Equation Goal for the drag coefficient of the cylinder as it was described before.
In the Expression box enter the formula:
{GG X - Component of Force 1}/(0.2*(0.0010115*10^5)^2)*(2*998.19*1).
8 Select No units in the Dimensionality list.
9 Click OK. Rename the Equation Goal 1 to Drag Coefficient.
Now you can solve all of the projects created for both the cylinders.

Solving a Set of Projects
Flow Simulation allows you to automatically solve a set of projects that exist in any
currently opened document.
1 Click Flow Simulation, Solve, Batch Run.
2 Select the Solve check
box in the All projects
row to select Solve for
all projects (Re 1,
Re 1000, Re 1e5). Also
select the Close Monitor
check box in the
All projects row. When
the Close Monitor check
box is selected, Flow
Simulation
automatically closes the
Solver Monitorwindow
when the calculation
finishes.
3 Click Run.
Getting Results
After all calculations are complete, go to the cylinder 0.01m model and activate the Re
1000 configuration. Create Goal Plot to obtain the Drag Coefficient value:
1 Click Flow Simulation, Results, LoadUnload Results.
2 In the Load Results dialog box, keep the default project’s results file (2.fld) and click
Open.
3 In the Flow Simulation Analysis tree, under
Results, right-click the Goals icon and select
Insert. The Goals dialog box appears.
4 Click Add All.
created. Switch to Excel to obtain the value.

5-14
cylinder 0.01m.SLDPRT [Re 1000]
Goal Name Unit Value Averaged Value Minimum Value Maximum Value
GG X - Component of Force [N] 0.000104929 9.71368E-05 8.75382E-05 0.000105358
Drag Coefficient [ ] 1.023705931 0.94768731 0.85404169 1.027899399
6 Activate the Re 1 configuration and load results. Create the goal plot for both the goals.
cylinder 0.01m.SLDPRT [Re 1]
GG X - Component of Force [N] 1.14448E-09 1.16764E-09 1.12756E-09 1.81674E-09
7 Switch to the cylinder 1m part, activate the Re 1e5 configuration, load results and
create the goal plot for both the goals.
cylinder 1m .SLDPRT [Re 1e5]
GG X - Component of Force [N] 0.482967811 0.478070888 0.465937059 0.491484755
Even if the calculation is steady, the averaged value is more preferred, since in this case
the oscillation effect is of less perceptibility. We will use the averaged goal value for the
other two cases as well.
You can now compare Flow Simulation results with the experimental curve.
0.1 1 10 100 1000 10000 100000 100000
0
Re
1E+07
Ref. 1 Roland L. Panton, “Incompressible flow” Second edition. John Wiley & sons Inc., 1995

6
Flow Simulation can be used to study the fluid flow and heat transfer for a wide variety of
engineering equipment. In this example we use Flow Simulation to determine the
efficiency of a counterflow heat exchanger and to observe the temperature and flow
patterns inside of it. With Flow Simulation the determination of heat exchanger efficiency
is straightforward and by investigating the flow and temperature patterns, the design
engineer can gain insight into the physical processes involved thus giving guidance for
improvements to the design.
A convenient measure of heat exchanger performance is its “efficiency” in transferring a
given amount of heat from one fluid at higher temperature to another fluid at lower
temperature. The efficiency can be determined if the temperatures at all flow openings are
known. In Flow Simulation the temperatures at the fluid inlets are specified and the
temperatures at the outlets can be easily determined. Heat exchanger efficiency is defined
as follows:
ε actual heat transfer
----------------------------------------------------------------------------= -
maximum possible heat transfer
The actual heat transfer can be calculated as either the energy lost by the hot fluid or the
energy gained by the cold fluid. The maximum possible heat transfer is attained if one of
the fluids was to undergo a temperature change equal to the maximum temperature
difference present in the exchanger, which is the difference in the inlet temperatures of the
hot and cold fluids, respectively: . Thus, the efficiency of a counterflow
( – inlet)
inle t Tcold
Thot
ε
inlet Thot
Thot
– out let
heat exchanger is defined as follows: = ------------------------------------
- if hot fluid capacity rate is less
inlet Tcold
Thot
– inlet
ε
outlet Tcold
Tcold
– inlet
than cold fluid capacity rate or = ------------------------------------
- if hot fluid capacity rate is more than
inlet Tcold
Thot
– inlet
cold fluid capacity rate, where the capacity rate is the product of the mass flow and the
specific heat capacity: C= (Ref.2)
m ·
c

Chapter 6 Heat Exchanger Efficiency
6-2
The goal of the project is to calculate the efficiency of the counterflow heat exchanger.
Also, we will determine the average temperature of the heat exchanger central tube’s wall.
The obtained wall temperature value can be further used for structural and fatigue
analysis.
Open the Model
Click File, Open. In the Open dialog box, browse to the Heat Exchanger.SLDASM
assembly located in the Tutorial 3 - Heat Exchanger folder and click Open (or double-click
the assembly). Alternatively, you can drag and drop the Heat Exchanger.SLDASM
file to an empty area of SolidWorks window.
Warm water
Creating a Project
2 Select Create new. In the Configuration
name box type Level 3. The ‘Level 3’
name was chosen because this problem
will be calculated using Result
Resolution level 3.
Click Next.
Cold water = 0.02 kg/s
Tinlet = 293.2 K
Air
Steel
Hot air = 10 m/s
Tinlet = 600 K

3 In the Units dialog box select the desired
system of units for both input and output
(results). For this project we will use the
International System SI by default.
Click Next.
4 In the Analysis Type dialog box among
Physical features select Heat conduction
in solids.
By default, Flow Simulation will consider
heat conduction not in solids, but only
within the fluid and between the walls and
the fluid (i.e., convection). Selecting the
Heat conduction in solids option enables
the combination of convection and
conduction heat transfer, known as conjugate heat transfer. In this project we will
analyze heat transfer between the fluids through the model walls, as well as inside the
solids.
Click Next.
5 Since two fluids (water and air) are used
in this project, expand the Liquids folder
and add Water and then expand the
Gases folder and add Air to the Project
Fluids list. Check that the Default fluid
type is Liquids.
Click Next.
6 Since we have selected the Heat conduction in solids option at the Analysis Type
step of the Wizard, the Default Solid dialog box appears. In this dialog you specify the
default solid material applied to all solid components. To assign a different material to
a particular assembly component you need to create a Solid Material condition for this
component.

6-4
If the solid material you wish to specify as
the default is not available in the Solids
table, you can click New and define a new
substance in the Engineering Database.
The tube and its cooler in this project are
made of stainless steel.
Expand the Alloys folder and click Steel
Stainless 321 to make it the default solid
material.
Click Next.
If a component has been previously assigned a solid material by the SolidWorks’
Materials Editor, you can import this material into Flow Simulation and apply this
solid material to the component in the Flow Simulation project by using the Insert
Material from Model option accessible under Flow Simulation, Tools.
7 In the Wall Condition dialog box, select
Heat transfer coefficient as Default outer
wall thermal condition.
This condition allows you to define the
heat transfer from the outer model walls to
an external fluid (not modeled) by
specifying the reference fluid temperature
and the heat transfer coefficient value.
Set the Heat transfer coefficient value to 5 W/m2/K.
In this project we do not consider walls roughness.
Click Next.
8 In the Initial Conditions dialog box under
Thermodynamics parameters enter
2 atm in the Value cell for the Pressure
parameter. Flow Simulation automatically
converts the entered value to the selected
system of units.
Click Next accepting the default values of
other parameters for initial conditions.

9 In the Results and Geometry Resolution
dialog box we accept the default result
resolution level 3 and the default minimum
gap size and minimum wall thickness.
Click Finish.
After finishing the Wizard you will complete the project definition by using the Flow
Simulation Analysis tree. First of all you can take advantage of the symmetry of the heat
exchanger to reduce the CPU time and memory required for the calculation. Since this
model is symmetric, it is possible to “cut” the model in half and use a symmetry boundary
condition at the plane of symmetry. This procedure is not required, but is recommended
for efficient analyses.
Symmetry Condition
1 Click Flow Simulation, Computational Domain.
2 In the X max box type 0.
3 Click the Boundary Condition tab.
4 In the At X max list select Symmetry.
5 Click OK.

Specifying a Fluid Subdomain
6-6
Since we have selected Liquids as the Default fluid type and Water as the Default fluid in
the Wizard, we need to specify another fluid type and select another fluid (air) for the fluid
region inside the tube through which the hot air flows. We can do this by creating a Fluid
Subdomain. When defining a Fluid Subdomain parameters we will specify Gas as the
fluid type for the selected region, Air as the fluid and the initial temperature of 600 K and
flow velocity of 10 m/s as the initial conditions in the selected fluid region.
1 Click Flow Simulation, Insert, Fluid Subdomain.
2 Select the Air Inlet Lid inner face (in contact with the
fluid). Immediately the fluid subdomain you are going
to create is displayed in the graphics area as a body of
blue color.
To specify the fluid subdomain within a fluid region
we must specify this condition on the one of the faces
lying on the region’s boundary - i.e. on the boundary
between solid and fluid substances. The fluid
subdomain specified on the region’s boundary will be
applied to the entire fluid region. You may check if the
region to apply a fluid subdomain is selected properly
by looking at the fluid subdomain visualization in the
graphics area.
3 Accept the default Coordinate System and the
Reference axis.
4 In the Fluid type list select Gases / Real Gases / Steam.
Because Air was defined in the Wizard as one of the
Project fluids and you have selected the appropriate fluid
type, it appears as the fluid assigned to the fluid
subdomain.
In the Fluids group box, Flow Simulation allows you to
specify the fluid type and/or fluids to be assigned for the
fluid subdomain as well as flow characteristics,
depending on the selected fluid type.

5 Under Flow Parameters in the Velocity in Z Direction
box enter -10.
Flow Simulation allows you to specify initial flow
parameters, initial thermodynamic parameters, and
initial turbulence parameters (after a face to apply the
Fluid Subdomain is selected). These settings are applied
to the specified fluid subdomain.
6 Under Thermodynamic parameters in the Pressure
box enter 1 atm.
Flow Simulation automatically
converts the entered value to the selected system of units.
7 Under Thermodynamic parameters in the Temperature
box enter 600.
These initial conditions are not necessary and the
parameters of the hot air inlet flow are defined by the
boundary condition, but we specify them to improve
calculation convergence.
8 Click OK . The new Fluid Subdomain 1 item
appears in the Analysis tree.
9 To easily identify the specified condition you can
give a more descriptive name for the Fluid
Subdomain 1 item. Right-click the Fluid
Subdomain 1 item and select Properties. In the
Name box type Hot Air and click OK.
You can also click-pause-click an item to rename it
directly in the Flow Simulation Analysis tree.
Specifying Boundary Conditions
1 Right-click the Boundary Conditions icon in the Flow Simulation Analysis tree and
select Insert Boundary Condition. The Boundary Condition dialog box appears.

6-8
2 Select the Water Inlet Lid
inner face (in contact with
the fluid).
The selected face appears
in the Faces to Apply the
Boundary Condition
list.
3 Accept the default Inlet
Mass Flow condition and
the default Coordinate
System and
Reference axis
.
4 Click the numerical value in the Mass Flow Rate Normal
to Face boxi and set it equal to 0.01 kg/s. Since the
symmetry plane halves the opening, we need to specify a
half of the actual mass flow rate.
5 Click OK . The new Inlet Mass Flow 1 item appears
in the Analysis tree.
This boundary condition specifies that water enters the steel jacket of the heat exchanger
at a mass flow rate of 0.02 kg/s and temperature of 293.2 K.
6 Rename the Inlet Mass Flow 1 item to Inlet
Mass Flow - Cold Water.
Next, specify the water outlet Environment Pressure
condition.

7 In the Flow Simulation Analysis tree, right-click
the Boundary Conditions icon and select Insert
Boundary Condition.
8 Select the Water Outlet Lid inner face (in
contact with the fluid). The selected face
appears in the Faces to Apply the Boundary
Condition list.
9 Click Pressure Openings and in the Type
of Boundary Condition list select the Environment
Pressure item.
10 Accept the value of Environment Pressure (202650
Pa), taken from the value specified at the Initial
Conditions step of the Wizard, and the default values of
Temperature (293.2 K) and all other parameters.
11 Click OK . The new Environment Pressure 1 item
12 Rename the Environment Pressure 1 item to
Environment Pressure – Warm Water.
Next we will specify the boundary conditions for the hot air flow.
13 In the Flow Simulation Analysis tree, right-click the Boundary Conditions icon and

6-10
14 Select the Air Inlet Lid inner face (in contact with
the fluid).
The selected face appears in the Faces to Apply
the Boundary Condition list. Accept the
default Coordinate System and Reference
axis.
15 Under Type select the Inlet Velocity condition.
16 Click the numerical value in the the Velocity
Normal to Face box and set it equal to 10 (type the
value, the units will appear automatically).
17 Expand the Thermodynamic Parameters item. The
default temperature value is equal to the value specified as
the initial temperature of air in the Fluid Subdomain
dialog box. We accept this value.
18 Click OK . The new Inlet Velocity 1 item appears in
the Analysis tree.
This boundary condition specifies that air enters the tube at the velocity of 10 m/s and
temperature of 600 K.
19 Rename the Inlet Velocity 1 item to Inlet Velocity – Hot Air.
Next specify the air outlet Environment Pressure condition.
select Insert Boundary Condition. The Boundary Condition dialog box appears.

21 Select the Air Outlet Lid inner face (in contact
with the fluid).
The selected face appears in the Faces to Apply
the Boundary Condition list.
22 Click Pressure Openings and in the Type of
Boundary Condition list select the Environment
Pressure item.
23 Check the values of Environment Pressure (101325
Pa) and Temperature (600 K). If they are different,
correct them. Accept the default values of other
parameters.
Click OK .
24 Rename the new item Environment Pressure 1
to Environment Pressure – Air.
This project involving analysis of heat conduction in solids. Therefore, you must specify
the solid materials for the model’s components and the initial solid temperature.
Specifying Solid Materials
Notice that the auxiliary lids on the openings are solid. Since the material for the lids is the
default stainless steel, they will have an influence on the heat transfer. You cannot
suppress or disable them in the Component Control dialog box, because boundary
conditions must be specified on solid surfaces in contact with the fluid region. However,
you can exclude the lids from the heat conduction analysis by specifying the lids as
insulators.

6-12
1 Right-click the Solid Materials
icon and select Insert Solid
Material.
design tree, select all the lid
components. As you select the lids,
their names appear in the
Components to Apply the Solid
Material list.
3 In the Solid group box expand the
list of Pre-Defined materials and
select the Insulator solid in the
Glasses & Minerals folder.
4 Click OK . Now all auxiliary
lids are defined as insulators.
The thermal conductivity of the Insulator substance is zero. Hence there is no heat
transferred through an insulator.
5 Rename the Insulator Solid Material 1 item to Insulators.
Specifying a Volume Goal
1 In the Flow Simulation Analysis tree, right-click the Goals icon and select Insert
Volume Goals.

2 In the Flyout FeatureManager
Design tree select the Tube part.
3 In the Parameter table select the Av
check box in the Temperature of
Solid row.
4 Accept the selected Use for Conv.
check box to use this goal for
convergence control.
5 In the Name template type
VG Av T of Tube.
6 Click OK .
Running the Calculation
1 Click Flow Simulation, Solve, Run. The Run dialog box appears.
2 Click Run.
After the calculation finishes you can obtain the temperature of interest by creating the
corresponding Goal Plot.
Viewing the Goals
In addition to using the Flow Simulation Analysis tree you can use Flow Simulation
Toolbars and SolidWorks CommandManager to get fast and easy access to the most
frequently used Flow Simulation features. Toolbars and SolidWorks CommandManager
are very convenient for displaying results.
Click View, Toolbars, Flow Simulation Results.
The Flow Simulation Results toolbar appears.
Click View, Toolbars, Flow Simulation
Results Features. The Flow Simulation
Results Features toolbar appears.

6-14
Click View, Toolbars, Flow Simulation Display. The
Flow Simulation Display toolbar appears.
The SolidWorks CommandManager is a dynamically-updated, context-sensitive toolbar,
which allows you to save space for the graphics area and access all toolbar buttons from
one location. The tabs below the CommandManager is used to select a specific group of
commands and features to make their toolbar buttons available in the CommandManager.
To get access to the Flow Simulation commands and features, click the Flow Simulation
tab of the CommandManager.
If you wish, you may hide the Flow Simulation toolbars to save the space for the graphics
area, since all necessary commands are available in the CommandManager. To hide a
toolbar, click its name again in the View, Toolbars menu.
1 Click Goals on the Results Main toolbar or CommandManager. The Goals dialog
box appears.
2 Click Add All to select all goals of the project
(actually, in our case there is only one goal) .
created.
You can view the average temperature of the tube on the Summary sheet.
Heat Exchanger.SLDASM [Level 3]
Goa l Name Unit Value Ave raged Va lue Minimum Va lue Ma x imum V alue Progre ss [%] Use In Convergence
VG Av T of Tube [K] 328.4682387 327.4703038 324.7176733 328.4682387 100 Yes
Iterations: 51
Analysis in terval: 21
Creating a Cut Plot
1 Click Cut Plot on the Flow Simulation Results Features toolbar. The Cut Plot
dialog box appears.

2 In the flyout FeatureManager design tree select Plane3.
3 In the Cut Plot dialog box, in addition to displaying
Contours , select Vectors .
4 Click View Settings in order to specify the temperature as the parameter for the
contour plot. By default the Pressure is specified.
5 On the Contours tab, in the Parameter
list, select Temperature.
6 Using the slider set the Number of colors
to maximum.
7 In the View Settings dialog box, click the
Vectors tab and set the Max velocity to
0.004 m/s.
8 Click OK to save the changes and return to
the Cut Plot dialog box.
9 Click OK . The cut plot is created but
the model overlaps it.
10 Click the Right view on the Standard Views toolbar.

6-16
11 Click Geometry on the Flow Simulation Display toolbar to hide the model.
Let us now display the flow development inside the exchanger.
Flow Simulation allows you to display results in all four possible panes of the SolidWorks
graphics area. Moreover, for each pane you can specify different View Settings.
12 Click Window, Viewport, Two View - Horizontal.
13 To restore the view orientation in the top pane, click Right view on the
Standard Views toolbar.
14 Click the bottom pane and select the Isometric view on the Standard
Views toolbar.
The gray contour around the pane
border indicates that the view is active.
15 On the Flow Simulation Display
toolbar, click Geometry , then
on the View toolbar click Hidden
Lines Visible to show the face
outlines. Click the top pane and set
the same display mode for it by
clicking Hidden Lines Visible
again.
To see how the water flows inside the
exchanger we will display the Flow
Trajectories. Click the bottom pane to
make it the active pane.

Displaying Flow Trajectories
1 Click Flow Trajectories on the Flow
Simulation Results Features toolbar. The
Flow Trajectories dialog appears.
2 Click the Flow Simulation Analysis tree tab
and select the Inlet Mass Flow – Cold Water
item.
This selects the inner face of the Water Inlet
Lid to place the trajectories start points on it.
list, select Velocity.
5 Set Max velocity to 0.004 m/s.
6 Click OK to save changes and return to the
Flow Trajectories dialog.
7 Click OK . Trajectories are created
and displayed.

6-18
By default the trajectories are colored in accordance
with the distribution of the parameter specified in the
Contours tab of the View Settings dialog box. This
is controlled by the Use from contours option on
the Flow Trajectories tab of the View Settings
dialog box. Since you specified velocity for the
contour plot, the trajectory color corresponds to the
velocity value.
Notice that in the top pane the temperature contours are still displayed. The different
view settings for each pane allow you to display contour plots for different physical
parameters simultaneously.
Since we are more interested in the temperature distribution let us color the trajectories
with the values of temperature.
1 Right-click in the graphics area of the
bottom pane and select View Settings.
box, select Temperature.
3 Click OK. Immediately the trajectories are
updated.

The water temperature range is less than the default
overall (Global) range (293 – 600), so all of the
trajectories are the same blue color. To get more
information about the temperature distribution in
water you can manually specify the range of interest.
Let us display temperatures in the range of inlet-outlet
water temperature.
The water minimum temperature value is close to 293 K. Let us obtain the values of air
and water temperatures at outlets using Surface Parameters. You will need these values to
calculate the heat exchanger efficiency and determine the appropriate temperature range
for flow trajectories visualization.
Surface Parameters allows you to display parameter values (minimum, maximum,
average and integral) calculated over the specified surface. All parameters are divided
into two categories: Local and Integral. For local parameters (pressure, temperature,
velocity etc.) the maximum, minimum and average values are evaluated.
Computation of Surface Parameters
1 Click Surface Parameters on the Flow Simulation Results Features toolbar.
The Surface Parameters dialog box appears.
2 Click the Environment Pressure -
Warm Water item to select the inner
face of the Water Outlet Lid.
3 Select Consider entire model to take
into account the Symmetry condition
to see the values of parameters as if the
entire model, not a half of it, was
calculated. This is especially convenient for such parameters as mass and volume flow.
4 Click Evaluate.
5 After the parameters are calculated click the Local tab.

6-20
You can see that the average water
temperature at the outlet is about
300 K.
Now let us determine the temperature of air at the outlet.
6 Switch back to the Definition tab.
7 Click the Environment Pressure -
Air item to select the inner face of the
Air Outlet Lid.
8 Click Evaluate.
9 After the parameters are calculated
click the Local tab.
You can see that the average air
temperature at the outlet is about
584 K.
10 Click the Integral tab. You can see
that the mass flow rate of air is
0.046 kg/s. This value is
calculated with the Consider
entire model option selected, i.e.
taking into account the Symmetry
condition.
11 Click Cancel to close the dialog
box.

Calculating the Heat Exchanger Efficiency
The heat exchanger efficiency can be easily calculated, but first we must determine the
fluid with the minimum capacity rate (C= m& c
). In this example the water mass flow rate
is 0.02 kg/s and the air mass flow rate is 0.046 kg/s. The specific heat of water at the
temperature of 300 K is about five times greater than that of air at the temperature of
584 K. Thus, the air capacity rate is less than the water capacity rate. Therefore,
according to Ref.2, the heat exchanger efficiency is calculated as follows:
inle t Thot
ε Thot
– out let
= ------------------------------,
inlet Tcold
Thot
– inlet
Thot
inlet Thot
outlet
where is the temperature of the air at the inlet, is the temperature of the
air at the outlet and Tinlet
cold
is the temperature of the water at the inlet.
We already know the air temperature at the inlet (600 K) and the water temperature at the
inlet (293.2 K), so using the obtained values of water and air temperatures at outlets, we
can calculate the heat exchanger efficiency:
ε Thot
inlet Thot
– outlet
------------------------------ 600 – 584
= = ---------------------------- = 0.052
Thot
– inlet
inlet Tcold
600 – 293.2
Specifying the Parameter Display Range
1 Right-click in the graphics area of the
bottom pane and select View Settings.
2 On the Contours tab, set Max temperature
to 300 K.
3 Using the slider set the Number of colors
to maximum.
4 Click OK. Immediately the trajectories are
updated.
If you specify the range, it may be convenient to display the global (calculated over the
Computational Domain) minimum and maximum values of the current contour plot
parameter.
5 Click Display Global Min Max on the Flow Simulation Display toolbar. The
temperature global minimum and maximum values appear at the top. The points where
the parameter value reaches its minimum or maximum will be highlighted in the
graphics area by color dots. The blue dots display locations of the points, where

6-22
parameter value is minimum, while the red ones display locations of the maximum
parameter value points. of the active (bottom) pane
As you can see, Flow Simulation is a powerful tool for heat-exchanger design
calculations.
Ref. 2 J.P. Holman. “Heat Transfer” Eighth edition.

7
Mesh Optimization
The goal of this tutorial example is to demonstrate various meshing capabilities of Flow
Simulation allowing you to better adjust the computational mesh to the problem at hand.
Although the automatically generated mesh is usually appropriate, intricate problems with
thin and/or small, but important, geometrical and physical features can result in extremely
high number of cells, for which the computer memory is too small. In such cases we
recommend that you try the Flow Simulation options allowing you to manually adjust the
computational mesh to the solved problem's features to resolve them better. This tutorial
teaches you how to do this.
The Ejector in Exhaust Hood example aims to:
• Settle the large aspect ratio between the minimum gap size and the model size by
adjusting the initial mesh manually.
• Resolve small features by specifying local mesh settings.

Chapter 7 Mesh Optimization
Problem Statement
7-2
The ejector model is shown on the picture. Note that the ejector orifice’s diameter is more
than 1000 times smaller than the characteristic model size determined as the
computational domain’s overall dimension.
Baffles
Ejector
Opening
Exhaust
Ejected chlorine orifice

SolidWorks Model Configuration
Copy the Tutorial 4 – Mesh Optimization folder into your working directory and ensure
that the files are not read-only since Flow Simulation will save input data to these files.
Open the Ejector in Exhaust Hood.SLDASM assembly.
Project Definition
Using the Wizard create a new project as follows:
Project Configuration Use current
Unit system USA
Analysis type Internal; Exclude cavities without flow conditions
Physical features Gravity; Default gravity (Y component:
-32.1850394 ft/s^2)
Fluids substances Air, Chlorine
Wall Conditions Adiabatic wall, default smooth walls
Initial Conditions Initial gas concentration: Air – 1, Chlorine - 0
Result and Geometry Resolution Default result resolution level 3;
Default geometry resolution: automatic minimum
gap size and minimum wall thickness, other
options by default
When you enable gravitation, pay attention that the hydrostatic pressure is calculated
with respect to the global coordinate system, as follows:
Phydrostatic = ρ(gx*x + gy*y+ gz*z), where ρ − reference density, gi - component of the
gravitational acceleration vector and x, y, z - coordinates in the global coordinate
system.
Conditions
At first, let us specify all the necessary boundary conditions because they influence the
automatic initial mesh through the automatic minimum gap size, which depends on the
characteristic size of the faces on which the boundary conditions are set.
Flow Simulation calculates the default minimum gap size using information about the
faces where boundary conditions (as well as sources, fans) and goals are specified.
Thus, it is recommended to set all conditions before you start to analyze the mesh.

7-4
The first two boundary conditions are imposed on the exhaust hood's inlet and outlet.
Inlet
Boundary
Condition
Environment Pressure:
Default values (14.6959 lbf/in2, gas
substance – Air) of the Environment
pressure and Temperature (68.09 °F)
at the box’s Lid for Face Opening;
Outlet
Boundary
Condition
Outlet Volume Flow:
Outlet volume flow rate of
1000 ft3/min at the box’s Exhaust Lid.
If you open the Initial Mesh dialog box (click Flow Simulation, Initial Mesh) and select
the Manual specification of the minimum gap size option, you can see that the current
automatic minimum gap size is 0.5 ft, which is the width of the outlet opening (if you have
opened the Initial Mesh dialog box, click Cancel to discard changes).
The next inlet volume flow rate condition defines the gas ejected from the bottom of the
Ejector component.
Inlet
Boundary
Condition
Inlet Volume Flow:
Inlet chlorine (Substance
concentrations: Chlorine – 1; Air – 0)
volume flow rate of 0.14 ft3/min at the
lid that closes the orifice (make sure
that you have selected the upper face
of the lid).

If you now look at the automatic minimum gap size value (click Flow Simulation, Initial
Mesh, Manual specification of the minimum gap size), you can see that it is close to the
orifice diameter - 0.0044528 ft.
The Minimum gap size is a parameter governing the computational mesh, so that a
certain number of cells per the specified gap should be generated. To satisfy this
condition the corresponding parameters governing the mesh are set by Flow
Simulation (number of basic mesh cells, small solid features refinement level, narrow
channel resolution, etc.). Note that these parameters are applied to the whole
computational domain, resolving all its features of the same geometric characteristics
(not only to a specific gap).
Since the minimum gap size value influences the mesh in the entire computational
domain, the large aspect ratio between the model and the minimum gap size value will
produce a non-optimal mesh: not only will all small gaps be resolved, but there will also
be many small cells in places where they are not necessary. As a result, an extremely large
mesh will be produced, which may result in overly large computer memory requirements
exceeding the computers' available resources. Moreover, if the aspect ratio between the
model and the minimum gap size is more than 1000, Flow Simulation may not adequately
resolve such models with the automatically generated mesh anyway.
Finally, let us create the ejector’s porous media and apply it to the ejector’s top and side
screens.
the Pre-Defined folder. You can skip the definition of the porous material, then when
creating the porous condition, select the pre-defined "Screen Material" from the
Engineering database.

7-6
Porous
Media
Screen material:
Porosity: 0.5,
Permeability type:
Isotropic,
Dependency on
velocity:
A = 0.07 kg/m4,
B = 3e-008 kg/(s*m3).
Components to apply:
Top Screen
Side Screen
To see advantages of the local mesh and refinement options better, now let us try to
generate the computational mesh governed by the automatic mesh settings. The resulting
mesh consists of more than 1100000 cells, and cannot be processed by old computers due
to the computer memory restriction (you may get a warning message about insufficient
memory)

Manual Specification of the Minimum Gap Size
We can distinguish two very different parts of the model: a relatively big cavity having
several thin walls within and no small solid features, and the ejector’s region containing
some very fine geometrical features. Therefore, the mesh required to properly resolve the
ejector and the mesh appropriate for the rest of the model should be also very different.
Since the ejector region is a part of the entire computational domain, we need to specify
such settings for the automatic mesh generation that the model’s geometry outside the
ejector’s region will be resolved without excessive mesh splitting.
The minimum gap size value, automatically defined from the dimensions of the ejector’s
Top Screen and Side Screen components, is too small and results in excessive mesh
splitting.
To define an appropriate minimum gap size we need to examine all narrow flow passages
outside the ejector’s region:
• Boundary conditions;
• The passages connecting the ejector’s internal volume with the model’s cavity;
• The narrow flow passages between the baffles.
After reviewing the model we can accept the width of
the gap between the middle and upper baffles as the
minimum gap size. To avoid excessive mesh splitting,
we will specify the same value for the minimum wall
thickness.
2 Use the slider to set the Level of the initial mesh to
5.
3 Select the Manual specification of the minimum
gap size checkbox and enter 0.067 ft in the
Minimum gap size box.
4 Select the Manual specification of the minimum
wall thickness checkbox and enter 0.067 ft in
the Minimum wall thickness box.
0.067 ft

7-8
5 Click OK.
The resulting mesh has significantly less cells than the mesh generated automatically with
the default values of Minimum gap size and Minimum wall thickness. The total number
of cells is less than 200 000.

Switching off the Automatic Mesh Definition
We have successfully reduced the number of cells, yet using the mesh of the higher level.
The higher level mesh provides better refinement in the regions with small geometrical
features. However, we actually do not need such a fine mesh in some regions where the
flow field changes slowly. We can further decrease the number of cells by switching off
the automatic definition of the mesh generation settings and adjusting these settings
manually. The decreased number of cells will provide us a computer memory reserve
needed to better resolve fine geometrical features of the ejector.
Click Flow Simulation, Project, Rebuild.
1 Click Flow Simulation, Initial Mesh. Switch off the automatic mesh settings by
clearing the Automatic settings check box. The Initial Mesh dialog box controls the
basic mesh and the initial mesh within the entire computational domain unless local
initial mesh settings are specified.
The mesh is named Initial since it is the mesh the calculation starts from and it could
be further refined during the calculation if the solution-adaptive meshing is enabled.
The initial mesh is constructed from the Basic mesh by refining the basic mesh cells in
accordance with the specified mesh settings. The Basic mesh is formed by dividing the
computational domain into slices by parallel planes which are orthogonal to the
Global Coordinate System’s axes.
The Initial Mesh’s parameters are currently set by Flow Simulation in accordance with the
previously specified automatic mesh settings, including Minimum gap size and Minimum
wall thickness.
2 Go to the Narrow channel tab and set
the Narrow channels refinement level
to 1. This allows us to reduce the
number of cells in the channels
between the baffles and the wall of the
Box.
The Narrow channels refinement level
specifies the smallest size of the cells in
model’s flow passages with respect to
the basic mesh cells. So if N = 0…7 is
the specified Narrow channels
refinement level, the minimum size of
the cells obtained due to the mesh refinement is 2N times smaller (in each direction of
the Global Coordinate System, or 8N times by volume) than the basic mesh cell’s size.

7-10
The resulting mesh is shown below. It has about 75 000 cells.

Using the Local Initial Mesh Option
The ejector’s geometry is resolved reasonably well. However, if you generate the mesh
and zoom in to the ejector’s orifice region, you will see that the gas inlet face is still
unresolved. The resolution of the boundary condition surface is very important for
correctly imposing the boundary condition. To resolve the gas inlet face properly we will
use the Local Initial Mesh option.
The local initial mesh option allows you to specify an initial mesh in a local region of the
computational domain to better resolve the model geometry and/or flow peculiarities in
this region. The local region can be defined by a component of the assembly, disabled in
the Component Control dialog box, or specified by selecting a face, edge or vertex of the
model. Local mesh settings are applied to all cells intersected by a component, face, edge,
or a cell enclosing the selected vertex.
1 Click Flow Simulation, Insert, Local Initial Mesh.
2 Select the inlet face of the ejector’s orifice or click the
Inlet Volume Flow 1 boundary condition in the Flow
Simulation Analysis tree to select the face on which
this boundary condition is applied.
3 Clear the Automatic settings check box
and switch to the Refining cells tab.
4 Select the Refine all cells checkbox and
use the slider to set the Level of refining
all cells to its maximum value of 7.
5 Click OK.

7-12
Now we have specified to refine all cells at the ejector’s orifice inlet face up to the
maximum level. The locally refined mesh is shown below.
Specifying Control Planes
The basic mesh in many respects governs the generated computational mesh. The proper
basic mesh is necessary for the most optimal mesh.
You can control the basic mesh in several ways:
• Change number of the basic mesh cells along the X, Y, Z-axes.
• Shift or insert basic mesh planes.
• Stretch or contract the basic mesh cells locally by changing the relative distance
between the basic mesh planes.
The local mesh settings do not influence the basic mesh but are basic mesh sensitive:
all refinement levels are set with respect to the basic mesh cell.
You may notice that the mesh resolving the ejector’s orifice inlet face is not symmetric. It
can has a negative effect on the specified boundary condition. We will add a control plane
to shift the boundary between cells so that it will pass through the center of the inlet face.
1 In the Initial Mesh dialog box, go to the Basic Mesh tab.
2 Click Add Plane. The Create Control Planes dialog box
appears.
3 In the Creating mode list select Reference geometry.
4 Under Parallel to select XY.
5 Zoom in to the ejector’s orifice area and select edge of the
inlet face in the graphics area. The control plane will pass
through the middle of the edge parallel to the Global
Coordinate System plane selected in the Parallel to group.
Please check that the value of offset along the Z axis,
appeared in the Control planes list, is equal to 0.703125 ft. If not, it means that you
have mistakenly selected another geometry feature. In this case, right-click on the

Control planes list and select Delete All, then try to select the edge of the inlet face
again.
6 Click OK. The Z2 Control Plane appears in the Control planes table.
You can visualize the basic mesh before solving the problem. To see the basic mesh,
click Draw basic mesh in the Initial Mesh dialog box or click Flow Simulation,
Project, Show Basic Mesh.
7 Click OK to save changes and close the Initial Mesh dialog box.
Then, generate the initial mesh to check whether the thin walls and the other geometry are
resolved.
2 Clear the Solve check box in order to generate the
mesh only.
3 Clear the Load results check box.
4 Click Run.
Prior to visualizing the initial computational mesh, let
us switch the Flow Simulation option to use the meshed geometry instead of the SW
model's geometry to visualize the results.
By default, Flow Simulation shows the SolidWorks model’s geometry when displaying
the results. Depending on how exactly the model has been resolved with the
computational mesh, the SolidWorks model’s geometry may differ from the geometry
used in the calculation. To display the real captured geometry the Use CAD geometry
option is reserved.
5 Click Tools, Options, then click Third Party.
6 On the Flow Simulation Options tab, under
General Options, select the Display mesh
check box.
7 Under View Options clear the Use CAD
geometry (Default) check box.
8 Click OK.
Next load the file with the initial computational
mesh: right-click the Results icon and select Load
Results, then select the 1.cpt file and click Open.
Note that the total number of cells is about 75 000.

7-14
The calculation results, including the current
computational mesh, are saved in the .fld files,
whereas the initial computational mesh is
saved separately in the .cpt files. Both of the
files are saved in the project folder, whose
numerical name is formed by Flow Simulation
and must not be changed.
Create a cut plot based on the CENTERLINE with the Mesh option selected. Create a
second cut plot based on the ejector’s orifice inlet face with the Offset of -0.00025 ft
relative to the selected face and the same settings as the first cut plot.
Now you can see that the generated mesh is symmetrical relative to the center of the inlet
face.
Creating a Second Local Initial Mesh
With the specified mesh settings the ejector’s geometry will be resolved properly. But we
need to create the mesh successfully resolving not only fine geometrical features, but the
small flow peculiarities as well. In the Ejector Analysis project such peculiarities can be
found within the internal volume of the ejector, where the thin stream of chlorine is
injected from the ejector’s orifice. Therefore the mesh within the ejector’s region must be
split additionally. To refine the mesh only in this region and avoid excessive splitting of
the mesh cells in other parts of the model, we apply a local initial mesh at the component
surrounding this region. The component was created specially to specify the local initial
mesh.
Set to resolved the LocalMesh2 component. Click Close after Flow Simulation shows
you a warning message. Note that this component was created so that there is a small
distance between the boundaries of the component and the solid feature of interest (i.e.,
the ejector). Because the local settings are applied only to the cells whose centers lie
within the selected model component, it is recommended to have the component's
boundaries offset from the solid component's walls.

After resolving the LocalMesh2 component an error message appears informing you that
the inlet volume flow condition is not in contact with the fluid region. The problem
disappears after disabling the component in the Component Control dialog box to treat it
as a fluid region.
Click Flow Simulation, Component Control and disable the
LocalMesh2 component. Click OK.
Rebuild the project by clicking Flow Simulation, Project,
Rebuild.
You can also disable components directly from the Local
Initial Mesh dialog box by selecting the Disable solid
components option on the Region tab.
Next specify the local mesh settings for the ejector’s region.
1 Select the LocalMesh2 component.
2 Click Flow Simulation, Insert, Local
Initial Mesh.
3 Clear the Automatic settings check box
and switch to the Narrow Channels tab.
4 Specify the Characteristic number of
cells across a narrow channel equal to
15.
5 Use the slider to set the Narrow
channels refinement level to 3.
6 Click OK.
The settings on the Narrow Channels tab controls the mesh refinement in the model’s
flow passages. Characteristic number of cells across a narrow channel box specify
the number of initial mesh cells (including partial cells) that Flow Simulation will try
to set across the model’s flow passages in the direction normal to solid/fluid interface .
If possible, the number of cells across narrow channels will be equal to the specified
characteristic number, otherwise it will be close to the characteristic number. If this
condition is not satisfied, the cells lying in this direction will be split to satisfy the
condition.
Rebuild the project. Create the mesh again (without the following calculation) and load
the 1.cpt file.
Click Flow Simulation, Results, Display, Geometry to hide the model.

7-16
Finally, let us compare how the final mesh resolves the solid geometry and the fluid region
within the ejector with only about 100 000 cells in contrast with 1 100 000 cells generated
by the automatic mesh settings.

7-18

8
Problem Statement
The Flow Simulation PE capability of EFD Zooming is demonstrated as an engineering
tutorial1 example of selecting a better heat sink shape for a main chip taking into account
other electronic components in an electronic enclosure.
The assembly model of the electronic enclosure including the main chip’s heat sink under
consideration is shown in picture. The fan installed at the enclosure inlet blows air
through the enclosure to the outlet slots with the goal of cooling the heated electronic
elements (having heat sources inside). The planar main chip is attached to a motherboard
made of an insulator. To cool the main chip better, its opposite plane surface is covered by
a heat sink cooled by the air stream from the fan.
1.This example can be run in Flow Simulation PE only.

Chapter 8 Application of EFD Zooming
8-2
Inlet Fan
PCB
Small Chips
Main Chip
Heat Sink
Capacitors
Power Supply
Mother Board
Electronic
enclosure
The problem’s engineering aim is to determine the temperature of the main chip when
using one of two heat sink designs. All other conditions within the enclosure will be
invariable. As a result, we will find out the difference in cooling capability between these
two competing shapes.
No.1
No.2
The heat sink’s competing shapes (No.1 and No.2)
As you can see, all components within the electronic enclosure except the main chip’s heat
sink are specified as coarse shapes without small details, since they do not influence the
main chip’s temperature which is the aim of the analysis (the enclosure model was
preliminary simplified to this level on purpose). On the contrary, the heat sink of each
shape is featured by multiple thin (thickness of 0.1 in) fins with narrow (gaps of 0.1 in)
channels between them.

Two Ways of Solving the Problem with Flow Simulation
Flow Simulation allows us to simplify the solution of this problem. Two possible
techniques are listed below.
In the first and more direct way, we compute the entire flow inside the whole electronic
enclosure for each heat sink shape with using the Local Initial Mesh option for
constructing a fine computational mesh in the heat sink’s narrow channels and thin fins.
Naturally, the Heat conduction in solids option is enabled in these computations.
In the other, two-stage way (EFD Zooming using the Transferred Boundary Condition
option), we solve the same problem in the following two stages:
1 computing the entire flow inside the whole electronic enclosure at a low result
resolution level without resolving the heat sink’s fine features (so, the parallelepiped
envelope is specified instead of the heat sink’s comb shape) and disabling the Heat
conduction in solids option;
2 computing the flow over the real comb-shaped heat sink in a smaller computational
domain surrounding the main chip, using the Transferred Boundary Condition option
to take the first stage’s computation results as boundary conditions, specifying a fine
computational mesh in the heat sink’s narrow channels and thin fins to resolve them,
and enabling the Heat conduction in solids option.
The first stage’s computation is performed once and then used for the second stage’s
computations performed for each of the heat sink’s shapes.
The EFD Zooming Approach
Let us begin from the second (EFD Zooming) approach employing the Transferred
Boundary Condition option. Then, to validate the results obtained with this approach, we
will solve the problem in the first way by employing the Local Initial Mesh option.

First Stage of EFD Zooming
8-4
In accordance with the 1st stage of EFD Zooming aimed at computing the entire flow
inside the electronic enclosure, it is not necessary to resolve the flow’s small features, i.e.,
streams between the heat sink’s fins, at this stage. Therefore, we suppress the heat sink’s
comb shape feature in the assembly model, obtaining the parallelepiped envelope instead.
A parallelepiped heat sink is used at the 1st stage of EFD Zooming.
The model simplification at this stage allows us to compute the electronic enclosure’s flow
by employing the automatic initial mesh settings with a lower level of initial mesh (we use
4) and accepting the automatic settings for the minimum gap size and the minimum wall
thickness. Moreover, at this stage it is also not necessary to compute heat conduction in
solids, since we do not compute the main chip temperature at this stage. Instead, we
specify surface heat sources of the same (5W) heat transfer rates at the main chip and heat
sink (parallelepiped) faces and at the small chips’ faces (they are heated also in this
example) to simulate heating of the air flow by the electronic enclosure. This is not
obligatory, but removing the heat conduction in solids at this stage saves computer
resources. As a result, the computer resources (memory and CPU time) required at this
stage are substantially reduced.
Project for the First Stage of EFD Zooming
Click File, Open. In the Open dialog box, browse to the Enclosure Assembly.SLDASM
assembly located in the Tutorial PE1 - EFD Zooming folder and click Open (or
double-click the assembly). Alternatively, you can drag and drop the
Enclosure Assembly.SLDASM file to an empty area of SolidWorks window. Make sure
that the Zoom – Global - L4 configuration is the active one. Note that heat sink
(HeatSink.SLDPRT) is the parallelepiped obtained by suppressing the heat sink’s cuts.

Project Definition
Project name Use current: Zoom – Global - L4
Unit system USA
Physical features No physical features are selected
Fluid Air
Wall Conditions Adiabatic wall, Default smooth walls
Initial Conditions Default conditions
Result and Geometry Resolution Result resolution level set to 4, other options are
default
For this project we use the automatic initial mesh and the default computational domain.
Note that Level of initial mesh is set
to 4 in accordance with the Result
resolution level specified in the
Wizard. The Result Resolution
defines two parameters in the
created project, namely, the Level of
initial mesh and the Results
resolution level. The Level of initial
mesh is accessible from the Initial
Mesh dialog box and governs the
initial mesh only. The Results
resolution level is accessible from
the Calculation Control Options
dialog box and governs the
refinement of computational mesh during calculation and the calculation finishing
conditions. The Geometry Resolution options, which also influence the initial mesh,
can be changed in the Initial Mesh box, and/or their effects can be corrected in the
Initial Mesh and Local Initial Mesh dialog boxes.

8-6
Unit System
After passing the Wizard, first we will adjust the system of units. The new custom system
of units is based on the selected USA pre-defined system, but uses Watts for power, and
inches for length.
1 Click Flow Simulation, Units.
2 Specify Inch for the Length and Watt for the
Total heat flow & power.
3 Click Save.
4 In the Save to Database dialog box, expand the
Units group and select the User Defined item.
5 Name the new system of units Electronics.
6 Click OK to return to the Unit System dialog box.
7 Click OK.
Conditions
We specify External Inlet Fan at the inlet, Environment Pressure at three outlets. For more
detailed explanation of how to set these conditions please refer to the First Steps -
Conjugate Heat Transfer tutorial.
Inlet
Boundary
Condition
External Inlet Fan:
Pre-Defined Fan Curves
PAPST DC-Axial Series
400 405 405 with default
settings (ambient pressure
of 14.6959 lbf/in2,
temperature of 68.09 °F)
set at the Inlet Lid;

Outlet
Boundary
Condition
Heat Sources
Environment Pressure:
Default thermodynamic
parameters (ambient
pressure of 14.6959 lbf/in2,
temperature of 68.09 °F)
for the Environment
pressure at the Outlet Lids.
As mentioned earlier in this chapter, to simulate the flow heating by the electronic
enclosure, we specify surface heat sources of the same (5W) heat transfer rates at the main
chip and the heat sink (parallelepiped) faces and at the small chips’ faces. Since we do not
consider heat conduction in solids in this project, the surface source can be applied only to
faces in contact with fluid. Follow the steps below to create the sources on the necessary
faces:
1 Click Flow Simulation, Insert, Surface Source.
In the Flyout FeatureManager Design Tree, select the Heat Sink and Main Chip
components. Flow Simulation automatically selects all faces of the Heat Sink and
Main Chip components. Faces that are not in contact with fluid must be removed from
the Faces to Apply the Surface Source list.
2 Click Filter Faces . Select Keep outer faces and
faces in contact with fluid.
3 Click Filter.
It is convenient to select all faces of the component by
selecting this component in the Flyout FeatureManager
Design Tree, though finding and removing unnecessary
faces from the selection manually (one by one) may
require excessive time, especially when there are many

8-8
faces to remove. The Filter allows you to remove unnecessary faces of specified type
from the list of selected faces.
4 Set the value of the source to 5 W.
The specified heat source value (Heat Transfer Rate) is
distributed among the selected faces in proportion to
their areas.
5 Click OK .
Following the same procedure, create a surface
source of the 5 W on the total surface of small chips.
Goals
Specify the surface goals of mass flow rate at the inlet and outlet.
Run the calculation. After the calculation is finished you can start the second stage of EFD
Zooming to focus on the main chip.
Save the model.

Second Stage of EFD Zooming
At the 2nd stage of EFD Zooming aimed at determining the main chip’s temperature, we
compute the flow over the heat sink in a smaller computational domain surrounding the
main chip, using the Transferred Boundary Condition option to take the first stage’s
computation results as boundary conditions. To compute the solids temperature, we enable
the Heat conduction in solids option. Since at this stage the computational domain is
reduced substantially, a fine computational mesh with an affordable number of cells can
be constructed in the heat sink’s narrow channels and thin fins, even when considering
heat conduction in solids during computation.
Project for the Second Stage of EFD Zooming
Activate the Zoom - SinkNo1 - L4 configuration. Note that heat sink’s cuts are resolved
now.
Project Definition
Project name Use current: Zoom - SinkNo1 - L4
Unit system Electronics
Analysis type Internal
Physical features Heat conduction in solids is enabled
Fluid Air
Default solid Metals/Aluminum
Wall Condition Default condition (Adiabatic); Default smooth
walls (0 microinches)
Initial Conditions Default initial conditions (in particular, the initial
solid temperature is 68.09°F)

8-10
Result and Geometry Resolution Result resolution
level set to 4;
Minimum gap
size = 0.1 in,
automatic
minimum wall
thickness;
other options are
default.
Here, we use the automatic initial mesh by specifying the Result resolution level (Level
of initial mesh) of 4, but in contrast to the first stage’s computation, we specify manually
the minimum gap size of 0.1 in to resolve the fine features of heat sink.
Next, we will reduce the computational domain to focus on the main chip, i.e. perform
EFD Zooming.
Computational Domain
When reducing the computational domain for EFD Zooming purposes, it is necessary to
take into account that the first stage’s computation results will serve as the boundary
conditions at this domain’s boundaries. Therefore, to obtain reliable results in the second
stage’s computations, we have to specify computational domain boundaries (as planes
parallel to the X-, Y-, Z-planes of the Global Coordinate system) satisfying the following
conditions:
1 the flow and solid parameters at these boundaries, taken from the first stage’s
computation, must be as uniform as possible;
2 the boundaries must not lie too close to the object of interest, since the object’s features
were not resolved at the first stage’s computation. The computational domain must be
large enough not to receive influence from more complex features of the newly added
object;
3 the boundary conditions transferred to or specified at the boundaries must be consistent
with the problem’s statements (e.g., if in the problem under consideration the mother
board is made of a heat-conducting material, then it is incorrect to cut the mother board
with computational domain boundaries, since this will yield an incorrect heat flux from
the chip through the mother board).
In this project we specify the following computational domain boundaries satisfying the
above-mentioned requirements. Click Flow Simulation, Computational Domain to adjust
the computational domain size as follows:
• Xmin = -2.95 in (entirely lies inside the electronic enclosure side wall made of
aluminum, this material does not influence the main chip’s temperature since it is
insulated from the chip by the heat-insulating mother board and the air flow, its

boundary condition is automatically specified as the 68.09 °F temperature specified
as the initial condition for all solids),
• Xmax = 0.7 in (the boundary conditions in the fluid region of this boundary are
transferred from the first stage’s computation results, the same boundary conditions
as at Xmin = -2.95 in are automatically specified at this boundary’s upper solid part
lying in the electronic enclosure’s aluminum wall, and the same boundary
conditions as at Zmin = -1 in are automatically specified at the lower solid part lying
in the mother board),
• Ymin = -1 in, Ymax = 4 in (the boundary conditions at these boundaries are specified
in the same manner as at Xmax = 0.7 in, as well as at the boundaries’ side parts also
lying in the aluminum wall),
• Zmin = -1.1 in (entirely lies inside the mother board specified as a heat insulator,
therefore the adiabatic wall boundary condition is automatically specified at this
boundary),
• Zmax = 1.2 in (entirely lies inside the electronic enclosure’s aluminum upper wall,
therefore the same boundary condition, as at Xmin = -2.95 in, are automatically
specified at this boundary).
Conditions
The reduced computational domain.
First, we specify Transferred Boundary Conditions.

8-12
Transferred Boundary Condition.
2 Add the Xmax, Ymax and Ymin
Computational Domain boundaries to
the Boundaries to apply the transferred
boundary condition list. To add a
boundary, select it and click Add, or
double-click a boundary.
3 Click Next.
4 At Step 2, click Browse to select the
Flow Simulation project whose results
will be used as boundary conditions for
the current Zoom – SinkNo1 - L4 project.
You can select a calculated project of any
currently open model, or browse for the
results (.fld) file.
5 In the Browse for Project dialog select the Zoom – Global - L4 configuration and
click OK.
6 Click Next.
7 At Step 3, accept Ambient as the Boundary condition type.
The Ambient boundary condition consists
of specifying (by taking results of a
previous calculation) flow parameters at
the boundary's section lying in the fluid,
so they will act during the calculation in
nearly the same manner as ambient
conditions in an external analysis. If Heat
Conduction in Solids is enabled, then the
solid temperature is specified at this
boundary's section lying in the solid (by
taking results of a previous calculation).
The heat flux at this boundary, which will be obtained as part of the problem solution,
can be non-zero.
8 Click Finish.
Specify the other conditions as follows:

Heat Sources
Volume Source of 5W heat
generation rate in the main chip;
Solid Materials
a) Main Chip is made of silicon
(Pre-Defined/Semiconductors);

8-14
b) MotherBoard and Enclosure are made of insulator
(Pre-Defined/Glasses & Minerals);
c) all other parts (e.g. the heat sink) are made of aluminum.
Goals
Specify the Volume Goals of maximum and average
temperatures of the main chip and the heat sink.
Run the calculation.
The obtained computational results are presented in tables and pictures below. These
results were obtained with the heat sink’s shape No.1.
If you look at the computational mesh you can see that it has two cells for each of the heat
sink’s channels, and two cells for each of the sink’s fins.
The mesh cut plot obtained for the heat sink No.1 at Y=-0.3 in.

In fact, the Minimum gap size and Minimum wall thickness influence the same
parameter, namely, the characteristic cell size. By default, Flow Simulation generates
the basic mesh in order to have a minimum of two cells per the specified Minimum gap
size. The number of cells per the Minimum gap size depends non-linearly on the Level
of initial mesh and cannot be less than two. In turn, the Minimum wall thickness
condition induces Flow Simulation to create the basic mesh having two cells (two cells
are enough to resolve a wall) per the specified Minimum wall thickness (regardless of
the specified initial mesh level). That’s why, if the Minimum wall thickness is equal to
or greater than the Minimum gap size, then the former does not influence the resulting
mesh at all.
Changing the Heat Sink
Let us now see how employing the heat sink’s shape No. 2 changes the computational
results. To do this, we change the heat sink configuration to the No.2 version, whereas all
the EFD Zooming Flow Simulation project settings of 2nd stage are retained. There is no
need to perform the EFD Zooming computation of 1st stage again, as we may use its
results in this project too.
The easiest way to create the same Flow Simulation project for the new model
configuration is to clone the existing project to this configuration.
Clone Project to the Existing Configuration
1 Click Flow Simulation, Project, Clone
Project.
2 Click Add to existing.
3 In the Existing configuration list select Zoom
- SinkNo2 - L4.
Click OK. After clicking OK, two warning
messages appear asking you to reset the
computational domain and to rebuild the
computational mesh. Select No to ignore the
resizing of computational domain, and Yes to
rebuild the mesh.

8-16
After cloning the project you can start the calculation immediately.
The obtained results are presented in tables and pictures below. It is seen that due to the
new shape of the heat sink the main chip’s temperature is reduced by about 15 °F. That is
caused by both the increased area of the heat sink’s ribs and streamlining the flow in the
heat sink’s narrow channels between the ribs (in heat sink No.1 about half of the channel is
occupied by a counterflow vortex).
The Local Initial Mesh Approach
To validate the results obtained with the EFD Zooming approach, let us now solve the
same problems employing the Local Initial Mesh option. To employ this option, we add a
parallelepiped surrounding the main chip to the model assembly and then disable it in the
Component Control dialog box. This volume represents a fluid region in which we can
specify computational mesh settings differing from those in the other computational
domain, using the Local Initial Mesh option.
The electronic enclosure configuration with the additional part for applying the Local Initial Mesh op
Flow Simulation Project for the Local Initial Mesh Approach (Sink No1)
To create the project we clone the Zoom – SinkNo1 - L4 to the existing LocalMesh –
SinkNo1 - N2 configuration, but in contrast to the previous cloning we reset the
computational domain to the default size so the computational domain encloses the entire
model.
Activate Zoom – SinkNo1 - L4 configuration.

Open the Clone Project dialog, click Add to
existing and, in the Existing configuration list
select the LocalMesh – SinkNo1 - N2 as the
configuration to which Flow Simulation will attach
the cloned project.
After clicking OK, confirm with Yes both the
appearing messages.
Conditions
First remove the inherited transferred boundary
condition. Right-click the Transferred
Boundary Condition1 item in the tree and select
Delete.
Next, copy the boundary conditions from the Zoom – Global - L4 configuration using the
Copy Feature tool.
1 ActivateZoom – Global - L4 configuration.
2 Click Flow Simulation, Tools, Copy Features. The
Copy Features dialog box appears.
3 Switch to the Flow Simulation analysis tree tab, hold
down the Ctrl key and in the Flow Simulation Analysis
tree select Environment Pressure 1 and External Inlet
Fan 1 items. These features appear in the Features to
copy list.
4 Select LocalMesh – SinkNo1 - N2 as the Target
Project.
5 Click OK .
6 Activate LocalMesh – SinkNo1 - N2 configuration.

8-18
Heat Sources
To the already existing volume
source of the 5W heat generation rate
in the main chip, add the total 5W
heat generation rate in the small
chips.
Solid Materials
The following material definitions
were inherited from the previous
project so you do not need to create
them again, but you need to edit the
Silicon Solid Material 1 to include
small chips and to edit Insulator Solid Material 1 to include inlet and outlet lids:
a) the Main Chip and small chips are made of silicon;
b) the MotherBoard, the Enclosure, the Inlet Lid and the Outlet Lids are made of
insulator;
c) PCB1 and PCB2 are made of user defined Tutorial PCB material, which is added to
the Engineering Database in the First Steps - Conjugate Heat Transfer tutorial example.
d) all other parts are made of the default aluminum.
Goals
Keep the cloned volume goals of maximum and average temperatures of the main chip
and the heat sink.
Level of Initial Mesh
Click Flow Simulation, Initial Mesh to adjust the automatic initial mesh settings.

Set the Level of initial mesh to 3. Since heat
conduction in solids is enabled, setting the Level of
initial mesh to 4 together with the local mesh settings
will produce large number of cells resulting in longer
CPU time. To decrease the calculation time for this
tutorial example we decrease the Level of initial mesh
to 3. Note that the Result resolution level is still equal
to 4 as it was specified in the Wizard. To see the value
of the result resolution level, click Flow Simulation, Calculation Control Options, and
then click Reset. To close the Reset dialog box, click Cancel.
Click Flow Simulation, Project, Rebuild.
Specifying Local Initial Mesh Settings
To apply the local mesh setting to a
region we need a component
representing this region to be disabled
in the Component Control dialog box.
Local Initial Mesh.
2 In the FeatureManager Design Tree,
select the LocalMesh component.
3 Click the Disable solid
components check box.
4 Clear the Automatic settings check box.
5 Go to the Narrow Channels tab and set the
Characteristic number of cells across a
narrow channel = 2 and Narrow channels
refinement level = 4.
6 Click OK.
The Narrow Channels term is conventional and used for the definition of the model’s
flow passages in the normal-to-solid/fluid-interface direction. The procedure of
refinement is applied to each flow passage within the computational domain unless you
specify for Flow Simulation to ignore the passages of a specified height with the
Enable the minimum height of narrow channels and Enable the maximum height of
narrow channels options. The Characteristic number of cells across a narrow

8-20
channel (let us denote it as Nc) and Narrow channels refinement level (let us denote
it as L) both influence the mesh in narrow channels in the following way: the basic
mesh in narrow channels will be split to have the specified Nc number per a channel, if
the resulting cells satisfy the specified L. In other words, whatever the specified Nc, a
narrow channel’s cells cannot be smaller in 8L (2L in each direction of the Global
Coordinate System) times than the basic mesh cell. This is necessary to avoid the
undesirable mesh splitting in superfine channels that may cause increasing the number
of cells to an excessive value.
In our case, to ensure the 2 cells across a channel criterion, we increased the Narrow
channels refinement level to 4.
We perform these settings for both of the heat sinks under consideration.
Flow Simulation Project for the Local Initial Mesh Approach (Sink No2)
Clone the active LocalMesh – SinkNo1 - N2 to the
existing LocalMesh – SinkNo2 - N2 configuration.
While cloning confirm the message to rebuild the
mesh.
Using the Batch Run calculate both projects.
Results
The computational results obtained for both of the heat sinks are presented below in
comparison with the results obtained with the EFD Zooming approach. It is seen that
computations with the local mesh settings yield practically the same results as the EFD
Zooming approach, therefore validating it.
The computed maximum and average main chip and heat sink temperatures when
employing the different heat sinks.
He at sink N o.1
Zoom -
S inkN o1 -
L4
LocalMesh -
S inkNo1 -
N 2
Heat s ink N o .2
Zoom -
SinkN o 2 -
L4
LocalMesh -
SinkN o 2 -
N 2
Parameter
tm ax, °F 111.1 114.1 96.4 99.4
tav er, °F 110.8 113.8 96.1 99.2
tm ax, °F 111 114.1 96.3 99.4
Ma in chip
He at sink ta v e r , °F 1 10.6 113.7 95. 9 99

EFD Zooming Local Mesh
The temperature cut plots obtained for heat sink No.1 at Y=2.19 in (Top plane) with the EFD Zooming (left) and
Local Mesh (right) approaches.
The temperature cut plots obtained for heat sink No.1 at Z= -0.32 in (Front plane) with the EFD Zooming (left) and
The temperature cut plots obtained for heat sink No.1 at X= -1.53 in (Right plane) with the EFD Zooming (left) and

The temperature cut plots obtained for heat sink No.2 at Y=2.19 in (Top plane) with the EFD Zooming (left) and
The temperature cut plots obtained for heat sink No.2 at Z=-0.32 in (Front plane) with the EFD Zooming (left)
and Local Mesh (right) approaches.
The temperature cut plots obtained for heat sink No.2 at X= -1.53 in (Right plane) with the EFD Zooming (left) an
8-22

9
Textile Machine
Problem Statement
The simplified textile machine used by this tutorial is described as a closed hollow cylinder
having a cylindrical stator with a narrow inlet tube. A thin-walled cone rotates at a very high
speed. The air flows over the rotating cone before leaving through the outlet pipe. Due to the
shear stress, the rotating cone swirls the air. The swirling air motion orients the fibers, for the
correct formation of yarn.
In this example1 a hollow cylinder with the following dimensions were used: 32 mm inner
diameter and 20 mm inner height. Air is injected into an inlet tube of 1 mm diameter at a
mass flow rate of 0.0002026 kg/s. The cone thickness is 1 mm and the cone's edge is
spaced at 3 mm from the bottom of the main cylinder. The cone rotates at a speed of
130000 RPM. The static pressure of 96325 Pa is specified at the cylinder's outlet tube exit.
Flow Simulation analyzes the air flow without any fiber particles. The influence of the
fiber particles on the air flow was assumed to be negligible. Small polystyrene particles
were injected into the air stream using the postprocessor Flow Trajectory feature to study
the air flows influence on the fibers. A 40 m/s tangential velocity of air is specified as an
initial condition to speed up convergence and reduce the total CPU time needed to solve
the problem.

Chapter 9 Textile Machine
Stator
Outlet
P = 96325 Pa
Inlet mass flow rate of
0.0002026 kg/s
9-2
Housing
Rotating wall
ω = 130000 RPM
1mm
Copy the Tutorial Advanced 2 - Rotating Walls folder into your working directory and
ensure that the files are not read-only since Flow Simulation will save input data to these
files. Open the Textile Machine.SLDASM assembly.

Project Definition
Project name Create new: 130000rpm
Unit system SI; select mm (Millimeter) for Length and RPM
Analysis type Internal;
Physical features No physical features are selected
Fluid Air
Result and Geometry Resolution Result resolution level set to 4;
Conditions
(Rotations Per Minute) for Angular Velocity
under Loads&Motion
Exclude cavities without flow conditions
Minimum gap size = 1 mm, automatic minimum
wall thickness, other options are default
Specify the inlet and outlet boundary conditions as follows:
Inlet
Boundary
Condition
Inlet Mass Flow = 0.0002026:
Inlet mass flow rate of
0.0002026 kg/s normal to the
inlet face of the Stator; To do
this, you may need to hide the
Initial Velocity 1 and Initial
Velocity 2 components.

Outlet
Boundary
Condition
Specifying Rotating Walls
9-4
2 Select Wall ,
then Real Wall.
3 In the Flyout
FeatureManager
Design Tree select
the Rotor
component. All the
rotor’s faces are
selected. However,
the top face is out of
the computational
domain and must be
excluded.
4 Click Filter Faces . Select Remove faces out of
computational domain .
5 Click Filter.
Outlet Static Pressure =
96325 Pa:
Static pressure of 96325 Pa at
the outlet face of the Housing
(the other parameters are
default).

6 Select Wall Motion.
7 Specify the Angular Velocity of 130000 RPM.
8 Select Y as the rotation Axis.
9 Click OK and rename the new Real Wall 1 item to
Rotating Wall = 130 000 rpm.
Initial Conditions - Swirl
To speed up the convergence, a 40 m/s tangential velocity of air is specified as an initial
condition within the housing. The Initial Velocity 1 and Initial Velocity 2 auxiliary
components are used to define a fluid domain.
1 Click Flow Simulation, Insert, Initial Condition.
2 In the Flyout FeatureManager Design Tree select the
Initial Velocity 1 and Initial Velocity 2 components.
3 Select the Disable solid components option. Flow
Simulation will treat these components as a fluid region.
4 Select Y in the Reference axis list.
5 Under Flow Parameters, click Dependency to
the right of the Velocity in X direction box. The
Dependency dialog box appears.
6 In the Dependency type list, select Formula
Definition.
7 In the Formula box, type the formula defining the
velocity in X direction: 40*cos(phi).
Here phi is the polar angle ϕ defined as shown on the
picture below.
ϕ

9-6
8 Click OK. You will return to the Initial Condition PropertyManager.
9 Click Dependency to the right of the
Velocity in Z direction box and specify
formula for the Z component of velocity:
-40*sin(phi).
10 Click OK.
11 Under Thermodynamic Parameters click
the Pressure box and type 99800 Pa.
12 Click OK .
13 Click-pause-click the new Initial Condition1 item and
rename it to vel = 40 ms.
Specifying Goals
Since the rotating cone swirls the air, it make sense to specify the air velocity as a goal to
ensure the calculation stops when the velocity is converged. In addition, let us specify the
static pressure surface goal at the inlet and the mass flow rate surface goal at the outlet as
additional criteria for converging the calculation.
Specify the following project goals:
GOAL TYPE GOAL VALUE FACE/COMPONENT
Global Goal Average Velocity
Surface Goal Mass Flow Rate Outlet face(click the outlet static
pressure boundary condition item to
select the outlet face)
Surface Goal Average Static Pressure Inlet face(click the inlet mass flow rate
boundary condition item to select the
inlet face)
Volume Goal Average Velocity Initial Velocity 1
(select the component in the Flyout
FeatureManager Design Tree)

Volume Goal Average Velocity Initial Velocity 2
Calculate the project.
Results - Smooth Walls
(select the component in the Flyout
FeatureManager Design Tree)
The calculated flow velocity field and velocity Y-component field at Z = 0 (XY section)
are shown in the pictures below. It can be seen that the maximum flow velocity occurs
near the inlet tube and near the rotating cone's inner surface at the cone's edge.
Velocity in the XY section at Z = 0.
Flow velocity Y-component of flow velocity
It is interesting that the vertical (i.e. along the Y axis) velocity in the region close to the
rotating cone's internal and external surfaces is directed to the cylinder bottom. Also, this
velocity component is nearly zero in the gap between the rotating cone and the bottom of
the cylinder, and positive (i.e. directed to the top) in the vicinity of the cylinder's side
walls. As a result, small particles carried by the air into the region between the lower edge
of the rotating cone and the bottom of the cylinder cannot leave this region due to the
small vertical velocity there. On the other hand, larger particles entering this region may
bounce from the cylinder’s bottom wall (in this example the ideal, i.e. full reflection is
considered) and fly back to the region of high vertical velocity. Then they are carried by
the air along the cylinder's side walls to the cylinder's top wall where they remain in this
region's vortex.

Displaying Particles Trajectories and Flow Streamlines
9-8
1 In the Flow Simulation Analysis tree, right-click the Flow Trajectories icon and select
Insert.
2 Click the Flow Simulation Analysis tree tab and then
click the inlet boundary condition icon
(Inlet Mass Flow = 0.0002026) to select the inlet face
from which the particles are injected.
3 Set the Number of Trajectories to 10.
4 Under Options select the Forward direction and
set Draw Trajectories As to Lines with Arrows .

5 Under Constraints increase the Maximum Length
of trajectories to 15000 mm.
The Maximum length option limits the
length of the trajectory to the specified
value. We increase this value to show
better the flow vorticity.
6 Click OK do display flow
streamlines.
To display particles trajectories, we need to specify initial particle properties (temperature,
velocity and diameter), particle's material, the wall condition (absorption or reflection)
and, optionally, the gravity.
1 In the Analysis tree, right-click the Particle
Studies icon and select Insert.
2 In the Injections tab, click Insert to specify an
injection. The Injection dialog box appears.
In the Injection dialog box you can specify
injection as a group of particles of the same
material and initial conditions such as velocity, diameter, temperature, etc. You can
also specify mass flow rate produced by the injection.

9-10
3 Click the inlet boundary condition icon (Inlet
Mass Flow = 0.0002026) in the tree to select
the inlet face from which the particles are
injected.
4 Set the Number of points to 5.
5 Click Settings tab.
6 Double-click the Value cell to the right of the
Particle Material.
7 Under Solids, Pre-Defined, Polymers select Polystyrene as particle’s material and
click OK.
8 Expand the Initial Conditions item and type
0.005 for the particle Diameter.
We leave unchanged the default zero values of
relative velocity and temperature, which means
that the velocity and temperature of particles
are equal to those of the incoming flow. We also
leave the default value of mass flow rate, since
it is used only to estimate mass rates of erosion
or accumulation, which we are not going to take into account.
9 Click OK to set the injection and return to the Particle Study dialog box.
10 Select Injection 1 and click Clone. Select Injection 2, click Edit and change the
diameter of particles to 0.015 mm. Then click OK to return to the Particle Study
dialog box.
11 Click Boundary Conditions tab.
12 Click Edit to edit boundary condition that are applied by default for all the models
walls.
13 In the Boundary Condition dialog box, select
Reflection.
14 Keep the other conditions and click OK to return
to the Particle Study dialog box. Click Settings
tab.
15 Increase the Maximum length of particles
trajectories to 15000 mm.
16 Click Run to run the calculation and exit the Particle Study dialog box.
17 In the Analysis tree, right-click the Particle Study 1 icon and select View Results.

18 In the Particle Study Results dialog box,
select Injection 1 and click 3D-View
Options.
19 Select to draw trajectories as Line with
Arrow and click OK.
20 Select Injection 2 and specify the same type to draw trajectories.
21 Select Injection 1 and click Show to show particles trajectories. Then click OK to exit
the Particle Study Results dialog box.
22 In the Analysis tree, right-click the Injection 2 icon and select Show.
Modeling Rough Rotating Wall
In the previous calculation zero roughness was used for the walls of the rotating cone's
internal and external surfaces. To investigate an influence of the rotating cone wall's
roughness, let us perform the calculation with the rotating cone's internal and external
surfaces' at 500 μm roughness under the same boundary conditions.
Create a new configuration by cloning the current project, and
name it 130000rpm - rough wall.
Adjusting Wall Roughness
1 Right-click the Rotating Wall = 130 000 rpm item and
select Edit Definition.
2 Under Wall parameters, select Adjust Wall
Roughness .
3 Specify the wall roughness of 500 micrometers.
4 Click OK .
Run the calculation.

Results - Rough Walls
9-12
The calculated fields of flow velocity and Y-component of velocity in different section are
shown below and reveal practically no change in the vertical velocity of the flow. As a
result, the flying particles’ trajectories are nearly identical to those in the case of smooth
walls. It is seen that increase in the roughness from 0 to 500 μm increases the vortex flow's
tangential velocity.
Velocity in the XY section at Z = 0 (roughness = 500 μm)
Flow velocity Flow velocity's Y-component
Velocity in the ZX section at Y = 2 mm
roughness = 0 μm roughness = 500 μm

Flow streamlines
Smooth wall Rough wall
Trajectories of 5 μm particles
Trajectories of 15 μm particles

9-14

10
Problem Statement
Let us consider a non-Newtonian liquid's 3D flow1 through a rectangular-cross-section
channel encumbered with seven circular cylinders arranged asymmetrically with respect
to the channel's midplane shown in Ref. 1. Following Ref. 1, let us consider the 3%
aqueous solution of xanthan gum as a non-Newtonian liquid. Its viscosity approximately
obeys the power law η = K ⋅ ( γ &
)n − 1 with a consistency coefficient of K = 20 Pa×sn and a
power-law index of n = 0.2, whereas its other physical properties (density, etc.) are the
same as in water (since the solution is aqueous).
The problem's goal is to determine the total pressure loss in the channel. Also, to highlight
the influence of the 3% xanthan gum addition to water on the channel's total pressure loss,
we will calculate the flow of water using the same volume flow rate within the channel.
The Flow Simulation calculations are performed with the uniform liquid velocity profile
at the channel inlet, the liquid’s volume flow rate is 50 cm3/s. The static pressure of 1 atm
is specified at the channel outlet. The calculation’s goal is the channel’s resistance to the
flow, i.e., the total pressure drop ΔРo between the channel inlet and outlet.

Chapter 10 Non-Newtonian Flow in a Channel with Cylinders
10-2
Copy the Tutorial Advanced 3 - Non-Newtonian Flow folder into your working
directory and ensure that the files are not read-only since Flow Simulation will save input
data to these files. Open the Array of Cylinders.sldprt part.
Specifying Non-Newtonian Liquid
2 In the Database tree, select Materials, Non-Newtonian Liquids, User Defined.
3 Click New Item in the toolbar. The blank Item Properties tab appears.
Double-click the empty cell to set the corresponding property value.
4 Specify the material properties as shown in the table below:
Name XGum
Density 1000 kg/m^3
Specific heat 4000 J/(kg*K)
Thermal conductivity 0.6 W/(m*K)
Liquid model Power law model
Consistency coefficient 20 Pa*sn
Power law index 0.2
Save and exit the database.
Project Definition
Project name Create new: XGS
Unit system CGS modified: Pa (Pascal) for the
Pressure & Stress
Analysis type Internal; Exclude cavities without flow
conditions
Physical features No physical features are selected (default)
Fluid XGum (non-Newtonian liquids);
Flow type: Laminar only (default)

Wall Conditions Adiabatic wall, default smooth walls,
Result and Geometry Resolution Default result resolution level 3;
Conditions
Specify boundary conditions as follows:
Inlet
Boundary
Condition
Outlet
Boundary
Condition
Specifying Goals
Inlet Volume Flow1:
50 cm3/s Volume flow rate normal to
face; default temperature (20.05 °C) at
the face;
Static Pressure1:
Default value (101325 Pa) for the Static
pressure at the face;
Specify surface goals for the Average
Total Pressure at the inlet and outlet.
Specify an equation goal for the total
pressure drop between the channel’s inlet
and outlet.
default slip condition
Minimum gap size=0.25 cm, no other
changes

10-4
Run the calculation. When the calculation is finished, create the goal plot to obtain the
pressure drop between the channel’s inlet and outlet.
Array o f C ylinders.SLDPRT [XGS]
Go a l Nam e Unit Va lue Ave ra ge d Va lue Minim um V a lue Ma x im um V a lue Progre ss [%]
SG A v Total P res sure 1 [P a] 105622.4926 105622.4125 105620.3901 105627.4631 100
Pres sure Drop [P a] 4293.481659 4293.4034 4298.457377 4291.380166 100
It is seen that the channel's total pressure loss is about 4 kPa.
Comparison with Water
Let us now consider the flow of water in the same channel under the same conditions (at
the same volume flow rate).
Create a new configuration by cloning the current
project, and name it Water.
Changing Project Settings
1 Click Flow Simulation, General
Settings.
2 On the Navigator click Fluids.
3 In the Project Fluids table, select
XGum and click Remove. Answer
OK to the appearing warning
message.
4 Select Water in Liquids and click
Add.
5 Under Flow Characteristics, change
Flow type to Laminar and Turbulent.
6 Click OK.
Run the calculation. After the calculation is finished, create the goal plot.

Array o f C ylinders.SLDPRT [water]
Go a l Nam e Unit Va lue Ave ra ge d Va lue Minim um V a lue Ma x im um V a lue Progre ss [%]
Pres sure Drop [P a] 65.6128767 65.68357061 65.76566097 65.55243288 100
As shown in the results table above, the channel's total pressure loss is about 60 Pa, i.e.
60...70 times lower than with the 3% aqueous solution of xanthan gum, this is due to the
water's much smaller viscosity under the problem's flow shear rates.
The XGS (above) and water velocity distribution in the range from 0 to 30 cm/s.
1 Georgiou G., Momani S., Crochet M.J., and Walters K. Newtonian and Non-Newtonian
Flow in a Channel Obstructed by an Antisymmetric Array of Cylinders. Journal of
Non-Newtonian Fluid Mechanics, v.40 (1991), p.p. 231-260.

10-6

11
Problem Statement
Let us consider a ball with diameter of 0.075 m, which is continuously heated by a 2 kW
heat source. The ball radiates heat to a concentrically arranged hemispherical reflector
with inner radius of 0.128 m and through a glass cover of the same inner diameter to a
circular screen with radius of 1.5 m arranged coaxially with the reflector at 1 m distance
from the ball. All parts except the glass cover are made from stainless steel. The ball’s
surface and the screen’s surface facing the ball are blackbody. The screen’s reverse side is
non-radiating. The tutorial’s goal is to see how the presence of reflector and its emissivity
influence the ball and screen temperatures. To do that, the following three cases are
considered1:
• Case 1: the reflector’s inner surface (i.e. that one which faces the ball) is whitebody;
• Case 2: all reflector surfaces are blackbody;
• Case 3: the reflector is removed.
The steady-state problem is solved with the Heat conduction in solids option checked,
so that conduction within all parts is calculated. Considering the convective heat transfer
negligibly low (as if, say, the whole construction was placed in highly rarefied air), we
also check the Heat conduction in solids only option. With this option, we do not need
to specify a fluid for the project, and it is calculated without considering any fluid flow
at all, thus saving the CPU time and limiting the heat transfer between parts to radiation
only. The initial temperature of the parts is assumed to be 293.2 K.
Let us consider the solutions obtained with Flow Simulation for each of the cases under
consideration.

Chapter 11 Heated Ball with a Reflector and a Screen
11-2
Copy the Tutorial Advanced 4 - Surface-to-surface Radiation folder into your working
directory and ensure that the files are not read-only since Flow Simulation will save input
data to these files. Open the Heated Ball Assembly.SLDASM assembly.
The heated ball with the reflector and the screen.

Case 1
Project Definition
Project name Create new: Case 1
Unit system SI
Analysis type External
Physical features Heat conduction in solids, Heat conduction in solids
only, Radiation, Environment radiation: Environment
Temperature = 293.2 K;
Default Solid Alloys/Steel Stainless 321
Wall conditions Default wall radiative surface: Non-radiating surface;
Initial and Ambient
Default initial solid temperature of 293.2 K
Conditions
Result and Geometry
Resolution
Set result resolution level to 3;
Automatic minimum gap size,
Manual minimum wall thickness - 0.007 m;
other options are default.
Definition of the Computational Domain
Specify the computational domain size as follows:
X min = -0.2 m Y min = -1.6 m Z min = -1.6 m
Xmax = 1.4 m Y max = 1.6 m Z max = 1.6 m

Adjusting Automatic Mesh Settings
11-4
Click Flow Simulation, Initial Mesh. Clear
the Automatic settings check box to
switch off the automatic initial mesh
settings, switch to the Solid/Fluid Interface
tab and change the Curvature refinement
level to 5. Click OK.
Definition of Radiative Surfaces
Follow the steps below to specify the radiative surfaces:
1 Click Flow Simulation, Insert, Radiative Surface.
2 Under Type, expand the list of Pre-Defined radiative
surfaces and select Blackbody wall.
3 In the Flyout FeatureManager Design Tree select the
Heated Sphere component. Next, select the surface of
Screen facing the Heated Sphere.
4 Click OK . Rename the new Radiative Surface 1
item to Blackbody Walls.

5 Click Flow Simulation, Insert, Radiative Surface.
6 Under Type, expand the list of Pre-Defined radiative
surfaces and select the Whitebody wall.
7 Select the Reflector’s inner surface.
8 Click OK . Change the name of the new radiative
surface to Whitebody Wall.
Specifying Bodies Transparent to the Heat Radiation
Specify the glass cover as transparent to radiation.
1 Click Flow Simulation, Radiation Transparent
Bodies.
2 Select the check box in the Thermal Transparency
column for the Glass component.
You can separately specify a component’s
transparency for solar radiation and transparency
for thermal radiation from all other sources,
including heated bodies. Since there are no sources
of solar radiation specified in the project, Thermal Transparency is the only available
option.
3 Click OK. Flow Simulation now treats this component as a body fully transparent to
the thermal radiation.
Heat Sources and Goals Specification
Specify the surface heat source of the heat generation rate at the sphere’s surface:

11-6
1 Click Flow Simulation, Insert, Surface Source.
2 In the Flyout FeatureManager Design Tree, select the
Heated Sphere component.
3 Select Heat Generation Rate as the source type and
set its value to 2000 W.
Specify surface goals of the maximum, average, and
minimum temperatures at the Heated Sphere’s surface
and the Screen's blackbody surface.
In addition, specify the volume goal for the Heated
Sphere’s average temperature. (Naturally, in all cases
you should select Temperature of Solid as the goal’s
parameter). You may rename the goals as shown to
make it easier to monitor them during the calculation.
Save the model and run the calculation.
If you take a look at the goals convergence, you can see that the sphere’s temperature at
the start of the calculation is high. This happens because the initial sphere’s temperature
(293.2 K) is too low to take away by radiation the heat produced by the 2000 W heat
source . To illustrate this better, in cases number 2 and 3 we will increase the initial
temperature of the heated sphere to 1000 K, thus providing the greater amount of heat is
being lost by the sphere starting from the very beginning of the calculation.
Case 2
In contrast to the Case 1, in this case the reflector’s
inner surface is blackbody and the reflector's other
surfaces are also blackbody.
Create a new Case 2 project by cloning the current Case
1.
Changing the Radiative Surface Condition
1 Delete the Whitebody Wall condition.
2 Right-click the Blackbody Walls item and select Edit
Definition.
3 Click the Reflector item in the Flyout FeatureManager
Design tree in order to select all its surfaces.
4 Click OK .

Goals Specification
Specify the additional surface goals for the maximum, average, and minimum
temperatures of the Reflector's inner and outer surfaces.
Specifying Initial Condition in Solid
Specify the initial temperature of the heated sphere of 1000
K using Initial Condition.
Save the model.
Case 3
In contrast to Case 1 and Case 2, the reflector is removed in Case 3.
Create a new Case 3 project by cloning the current Case 2.
1 Edit definition of the Blackbody Walls condition: delete all the Reflector’s faces. To
delete a face from the list of Faces to Apply the Radiative Surface, select the face
and press the Delete key.
2 Delete the surface goals related to reflector.
3 Disable the Reflector component in the
Component Control dialog box.
Using Batch Run, calculate the cases 2 and 3.

Results
11-8
In Case 1, due to the radiation returned by the reflector, the ball’s surface facing the
reflector is hotter than the ball’s surface facing the screen (see pictures below). Therefore,
screen temperature in Case 1 is higher than in the other cases.
In Case 2, radiation coming from the ball to the reflector heats up the reflector and heat is
radiated from the reflector’s outer surface to ambient, therefore being lost from the
system. Since the heat returned to the ball by the reflector’s radiation is smaller, the ball’s
temperature is lower, although distributed over the ball in the same manner as in Case 1.
The heat coming from the reflector to the screen is also smaller. As a result, the screen’s
temperature is lower than in Case 1.
Since the reflector is removed in Case 3, there is no noticeable heat radiated back to the
ball. The ball’s temperature is lower than in Case 2 and mostly uniform (the
non-uniformity is lower than 1 K). Since the screen acquires radiation from the ball only,
the screen’s temperature is the lowest among all the cases.
The ball temperature distribution (front plane cross-section) in CASE 1 (left), CASE 2 (center) and
CASE 3 (right) in the range from 1200 to 1220 K (the reflector is arranged at the left).
The screen temperature distribution (surface plot of solid temperature) in CASE 1 (left), CASE 2
(center) and CASE 3 (right) in the range from 295 to 340 K.

Case 1 Case 2 Case 3
Maximum 1233.04 1206.31 1195.97
Average 1222.16 1203.30 1195.47
Minimum 1211.98 1200.38 1195.39
Maximum 345.93 324.89 313.60
Average 317.78 308.90 303.55
Minimum 306.74 302.52 299.51
Parameter
The b all’s temperature, K
The screen’s tempera ture , K

11-10

12
Rotating Impeller
Problem Statement
Let us consider the air flow through a centrifugal pump having a rotating impeller (see
below).1 This pump has a stationary axial inlet (an eye), a pipe section of 92 mm radius
with a central body of circular arc contour, which turns the flow by 90o from the axial
direction. At the inlet's exit the radial air flow is sucked by a rotating impeller, which has
seven untwisted constant-thickness backswept blades with wedge-shape leading and
trailing edges. Each blade is cambered from 65o at the impeller inlet of 120 mm radius to
70o at the impeller exit of 210 mm radius, both with respect to the radial direction. These
blades are confined between the impeller shrouding disks rotating with the same (as the
blades) angular speed of 2000 rpm. Downstream of the impeller the air enters a stationary
(non-rotating) radial diffuser.
To complete the problem statement, let us specify the following inlet and outlet boundary
conditions: inlet air of 0.3 m3/s volume flow rate having uniform velocity profile with
vectors parallel to the pump's axis; at the radial-directed outlet a static pressure of 1 atm is
specified.

Chapter 12 Rotating Impeller
Outlet Static Pressure
Inlet Volume Flow
The centrifugal pump with a rotating impeller.
12-2
Copy the Tutorial Advanced5 - Rotating Impeller folder into your working directory.
Open the Pump.SLDASM assembly.
Project Definition
Project name Use current: Impeller Efficiency
Unit system SI
Physical features Rotation: Type - Global rotating, Rotation axis - Z
axis of Global Coordinate system, Angular
velocity=2000 RPM (209.43951 rad/s)
Default fluid Air
Result and Geometry Resolution Set the Result resolution level to 4;
Minimum gap size = 0.04 m, minimum wall
thickness = 0.01, other options are default
Ω = 2000 rpm

Conditions
Specify the inlet and outlet boundary conditions as described below.
Inlet
Boundary
Condition
Inlet Volume Flow:
Volume flow rate of
0.3 m^3/s (uniform velocity
profile) normal to the inner
face of the Cover in the
absolute frame of reference
(the Absolute option is
selected);
Relative to rotating frame. When the Relative to rotating frame option button is
selected, the specified velocity (Mach number) is assumed to be relative to the rotating
reference frame (Vr):
Vspecified = Vr = Vabs −ω × r
Here, r is the distance from the rotation axis and ω is the angular velocity of the
rotating frame. The mass or volume flow rate specified in the rotating reference frame
(the Relative to rotating frame option is selected) will be the same in the absolute
(non-rotating) frame of reference if the tangential velocity component is perpendicular
to the opening’s normal, thus not influencing the mass (volume) flow rate value, e.g.
when the opening's normal coincides with the rotation axis.
Outlet
Boundary
Condition
Outlet Environment
Pressure:
Default value (101325 Pa)
for the Environment pressure
(in the absolute frame of
reference - the Pressure
potential is disabled) at the
radial outlet face.
Pressure potential. If you enable a rotating reference frame, you can select the
Pressure potential check box. When the Pressure potential check box is selected, the
specified static pressure is assumed to be equal to the rotating frame pressure (Pr) and
may be calculated using following parameters: absolute pressure, density, angular
velocity and radius:
2 2 1
2 specified r abs P = P = P − ρω ⋅ r
When the Pressure potential check box is unchecked, the specified static pressure is
assumed to be a pressure in terms of the absolute frame of reference (Pabs).

12-4
When you specify a rotating reference frame, it is assumed that all model walls are rotated
with the reference frame's angular velocity unless you set a specific wall to be stationary.
To specify a non-rotating wall, the Stator moving wall boundary condition can be applied
to this wall. Specifying the stator boundary condition is the same as specifying the zero
velocity of this wall in the absolute (non-rotating) frame of reference. Note that stator face
must be axisymmetric with respect to the rotation axis.
Specifying Stationary Walls
We will specify the stator condition at the corresponding walls of the pump’s cover.
To easily select the necessary faces, hide the Impeller component by right-clicking the
component name in the FeatureManager Design tree and selecting Hide components .
In addition, check to see that the Enable selection through transparency option is
enabled under Tools, Options, System Options, Display/Selection.
1 Select the inner faces of Cover as shown.
2 Click Flow Simulation, Insert, Boundary
Condition.
3 Click Wall and keep the default Real
Wall condition type.
4 Select Stator.
5 Click OK and rename the new Real Wall 1 condition to Stator Walls.

Impeller’s Efficiency
Engineers dealing with pump equipment are interested in the pump efficiency. For the
pump under consideration the efficiency (η) can be calculated in the following way
(F.M.White "Fluid Mechanics", 3rd edition, 1994):
( P − P ) ⋅
Q
outlet inlet M
η
=
Ω ⋅
where Pinlet is the static pressure at the pump’s inlet, Poutlet is the bulk-average static
pressures at the impeller’s outlet (Pa), Q is the volume flow rate (m3/s), Ω is the impeller
rotation angular velocity (rad/s), and M is the impeller torque (N·m). To obtain Poutlet, an
auxiliary measure component was placed where the flow exits the impeller.
The measure component is only used for the pressure
measurement (the corresponding goal will be specified at the
inner face of the measure thin ring), thus it should be
disabled in the Component Control dialog box.
1 Click Flow Simulation, Component Control.
2 Select the Measure item and click Disable.
3 Click OK to close the dialog.
Specifying Project Goals
First, since the pressure and volume flow rate boundary condition are specified, it makes
sense to set the mass flow rate surface goal at the pump’s inlet and outlet to inspect the
mass balance as an additional criterion for converging the calculation.
GOAL TYPE GOAL PARAMETER FACE
Surface Goal Mass Flow Rate Inlet face
Surface Goal Mass Flow Rate Outlet face
Next, specify the goals that are necessary for calculating the impeller’s efficiency:
GOAL TYPE GOAL PARAMETER FACE
Surface Goal Av Static Pressure Inlet face

12-6
Surface Goal Bulk Av Static Pressure The inner face of
To avoid manual selecting of all impeller’s faces in contact with air (more than 150) we
will use the Filter Faces feature.
1 Select the Impeller component by clicking on it in the graphic area or in the
FeatureManager Design tree.
2 Right-click on Goals item in the Analysis tree and select
Insert Surface Goals. All impeller faces (including those
we do not actually need) appear in the Faces to Apply the
Surface Goal list.
3 Click Filter Faces and select Remove outer
faces and Keep outer faces and faces in contact
with fluid options.
When several options are selected in the faces filter, the
filter options to exclude certain faces are combined with
the use of logical AND, so that the combination of Remove
outer faces and Keep outer faces and faces in contact
with fluid leads to the removal of all faces but those in
contact with fluid.
4 Click Filter.
Rename the created goals as shown below:
the Measure ring
at the impeller's
outlet.
Surface Goal Z - Component of Torque All impeller faces in contact with air
(see details below).

Finally, specify the following Equation goals:
GOAL NAME FORMULA DIMENSIONALITY
Pressure Drop {SG Av Static Pressure
Inlet}-{SG Bulk Av Static
Pressure Impeller's Outlet}
Pressure &
stress
Efficiency {Pressure Drop}*{Inlet Volume
Flow 1:Volume flow rate normal
to face:3.000e-001}/209.44/
{Torque on Impeller}
No units
To add inlet volume flow value to the equation goal’s expression, click the
Inlet Volume Flow 1 item in the Analysis tree and then click Volume flow rate normal
to face in the Parameter list.

Results
12-8
The velocity vectors and static pressure distribution are shown below. To display vectors
in the rotating reference frame select the Velocity RRF parameter under the Vectors tab of
the View Settings dialog box.
The flow velocity vectors in the frame rotating with the impeller (left) and in the
stationary frame (right) at the impeller flow passage midsection (Z = - 0.02 m, Front
plane, vector spacing = 0.02m, arrow size = 0.03m).
The flow static pressure at the impeller flow passage midsection.

The flow pressure distribution
For the impeller under consideration the obtained efficiency is 0.79.
Efficiency [ ] 0.787039615 0.786371 0.784334 0.787117

12-10

13
CPU Cooler
Problem Statement
Let us consider a CPU cooler consisting of a copper core and an aluminum heat sink with
62 fins. An eight-blade propeller generates a constant flow of air through the heat sink.
The CPU is mounted on a socket installed on a PCB. Heat produced by the CPU is
transferred through the core to the heat sink and then released into the air flow.
To calculate the problem using
Flow Simulation, it is convenient
to use the concept of local rotating
regions. In order to simplify the
problem statement, we do not
consider the thermal interface
layer between the processor and
the cooler. Also, we neglect the
thermal conduction through the
processor socket and PCB.
A quantitative measure of the
cooler efficiency is the thermal
characterization parameter
, where Tc is
ΨCA = (TC – TA) ⁄ PD
the temperature of the CPU cover,
TA is the surrounding air
temperature, and PD is the thermal
design power (TDP) of the CPU.
SolidWorks Model
Fan
Heat sink
Copper core
CPU
An exploded view of the CPU cooler assembly.

Chapter 13 CPU Cooler
13-2
Configuration
Copy the Tutorial Advanced 6 - CPU Cooler folder into your working directory. Open
the CPU Cooler.SLDASM assembly.
Project Definition
Project Configuration Use current
Unit system SI
Analysis type External; Exclude cavities without flow conditions;
Physical features Heat conduction in solids;
Default fluid Gases / Air
Default solid Glasses and Minerals / Insulator
Wall Conditions Default smooth walls
Initial and Ambient Conditions Thermodynamic parameters: Temperature=38°C;
Result and Geometry Resolution Set the Result resolution level to 5; Minimum gap
Computational Domain
Exclude internal space
Rotation: Type - Local region(s)
Solid parameters: Initial solid temperature=38°C;
other conditions are default
size = 0.001 m, other options are default
Specify the computational domain size as follows:
X min = -0.095 m Y min = 0.0005 m Z min = -0.095 m
X max = 0.095 m Y max = 0.1123 m Z max = 0.095 m

Rotating Region
The Rotating region is used to calculate flow through rotating components of model
(fans, impellers, mixers, etc.) surrounded by non-rotating bodies and components, when a
global rotating reference frame cannot be employed. For example, local rotating regions
can be used in analysis of the fluid flow in the model including several components
rotating over different axes and/or at different speeds or if the computational domain has a
non-axisymmetrical (with respect to a rotating component) outer solid/fluid interface.
Each rotating solid component is surrounded by an axisymmetrical rotating region which
has its own coordinate system rotating together with the component.
A rotaing region is defined by an additional component of the model. This additional
component must meet the following requirements:
• the rotating component must be fully enclosed by it,
• it must be axisymmetric (with respect to the rotating component's rotation axis),
• its boundaries with other fluid and solid regions must be axisymmetrical too, since
the boundaries are sliced into rings of equal width and the flow parameters' values
transferred as boundary conditions from the adjacent fluid regions are
circumferentially averaged over each of these rings,
• the components defining different rotating regions must not intersect.
Specify the rotating region as follows:
1 Click Flow Simulation, Insert, Rotating Region.
2 In the flyout FeatureManager design tree select Rotation Region component. Note that
the Disable solid components check box is automatically selected to treat the Rotating
Region as a fluid region.

13-4
A component to apply a rotating region must be a body of revolution whose axis of
revolution is coincident with the rotation axis. This component must be disabled in the
Component Control. The border of a component may intersect with the solid bodies,
however, all those bodies must be also axisymmetrical. Since the flow on the boundary
of the rotating region must be axisymmetrical as well, we must provide a reasonable
gap between the rotating region boundary and the outer edges of the propeller blades
in order to minimize the influence of local non-axisymmetrical perturbations. Due to
the same reason, it is preferable to put the rotating region boundary inside the solid
bodies whenever possible, rather than putting them in the narrow flow passages. Also,
the supposed direction of the flow at the rotating region boundary should be taken into
account when defining the shape of the rotating region. You should choose such shape
of the rotating region that the flow direction will be as much perpendicular to the
rotating region boundary as possible. The picture below provides an additional insight
into how the rotating region shape was adapted to the actual geometry of the CPU
cooler in this tutorial example (the rotation region boundary is denoted by red).
These gaps are necessary for
flow to be more axisymmetrical
at the rotating region boundary
By placing the
rotating region
boundary within a
solid instead of
putting it into a
narrow channel
between the fan and
the attach clip we
avoid the additional
mesh refinement
and the negative
effects of the
non-axisymmetrical
flow in this narrow
channel
Here the rotating region boundary is placed
within a solid to avoid unnecessary and
non-realistic calculation of a swirled flow within
the closed cavity, which may yield inaccurate
results

3 Under Parameter, in the Angular Velocity box, specify the angular rotation
velocity of -4400 RPM.
During the definition of a rotation
region, heavy green arrows
denoting the rotation axis and the
positive direction of rotation speed
can be seen in the graphics area.
Since we want to define the
rotation in the direction opposite
to the arrow, we specify negative
value of the angular velocity.
4 Click OK .
When you specify a rotating region, it
is assumed that all model walls within
this region rotate with the region's
angular velocity unless you set a
specific wall to be stationary. To specify a non-rotating wall, the Stator real wall boundary
condition should be applied to the wall. Specifying the stator boundary condition is the
same as specifying the zero velocity of this wall in the absolute (non-rotating) frame of
reference. Note that the stator face (or a part of the face that is located inside the rotating
region in the case when the given face intersects with the rotating region boundary) must
be axisymmetric with respect to the rotation axis.
Specifying Stationary Walls
We will specify the stator condition at the appropriate walls of the fan attach and the
attachment clip. To easily select the necessary faces, hide the Fan and Rotation Region
components.
1 Click Flow Simulation, Insert, Boundary Condition.
2 Under Type, click Wall and keep the default Real
Wall condition type, then select Stator.

13-6
3 Select the two inner circular side faces and
two top faces of Attach Clip as shown.
4 In the flyout FeatureManager Design Tree
select the Fan Attach component.
The Fan Attach component has a relatively
complex shape with fine features, so it is
preferable to select the whole component
and then use the faces filter, rather than
selecting manually each face we need.
5 Click Filter Faces and select Remove
outer faces and Keep outer faces
and faces in contact with fluid .
Since we have specified the Exclude internal space option in the Wizard, the faces in
contact with the cavity between the Fan Attach and the Copper Core are considered
outer faces. Therefore we need to select the Remove outer faces option in Filter
Faces in order to exclude them.
6 Click Filter.
7 Click OK .
Solid Materials
Specify the solid materials for the project as follows:
a) the CPU and the Heat Sink are made of aluminum (Pre-Defined/Metals);
b) the Copper Core, naturally, is made of copper (Pre-Defined/Metals);
c) all other parts are made of default Insulator.
Heat Source
Define the volume source with the heat generation rate of 75 W in the CPU component.
Initial Mesh Settings
To resolve the complex geometry of the fan and heat sink better, let us define six
additional control planes and specify the proper Ratios for the intervals between them to
make the mesh denser in the central region containing the complex geometry and coarser
near the computational domain’s boundaries.

2 Clear the Automatic settings check box.
3 On the Basic Mesh tab, under
Control Intervals select the 0 m
value (either as a Max of X1 interval
or as a Min of X2 interval) and click
Delete plane.
4 Click Add plane. In the Create
Control Planes window make sure that Creating mode
is set to Click on screen and Parallel to is set to YZ,
click anywhere in the graphic area and enter manually
-0.05 as a new value for X. Click OK to return to the
Initial Mesh window.
5 Following the same procedure, add one more plane at
X = 0.05.
By default, Flow Simulation creates six control planes on
the computational domain boundaries and a number of
planes inside it. We now want to tune the set of control planes to our needs by removing
the default planes inside the computational domain and adding new ones.
6 Click the Ratio cell of the X1 interval and enter the value of 2. In the same manner
enter the values 1 and -2 for the intervals X2 and X3.
Ratio is the ratio of cell sizes on the given interval. The cell sizes are changed
gradually along the selected direction so that the proportion between the first and the
last cells of this interval is close (but not necessarily equal) to the entered value of the
Ratio. Negative values of the ratio correspond to the reverse order of cell size increase.

13-8
7 Delete the existing inner control
planes perpendicular to Y and add
new planes at Y = 0.042 m and
Y = 0.047 m. Specify the Ratio
values for Y1, Y2 and Y3 intervals
as 1.5, 1 and -1.4, respectively.
8 Delete the existing inner control
plane perpendicular to Z and add
new planes at Z = -0.05 m and
Z = 0.05 m. Specify the Ratio
values for Z1, Z2 and Z3 intervals as
2, 1 and -2, respectively.
9 Check that the Numbers of cells
per X, Y and Z are 26, 12 and 26, respectively. If the numbers are different, please
correct them manually.
10 To avoid the unnecessary mesh
refinement at the edges of the
heatsink fins, go to the Solid/fluid
Interface tab and set Small solid
features refinement level to 3,
Tolerance refinement level to 2,
and Tolerance refinement criterion
to 0.001 m, while leaving other
options default.
11 Go to the Narrow Channels tab and
set Characteristic number of cells
across a narrow channel to 4 and
Narrow channels refinement level
to 1, leaving default values for other
options. This will prevent the
unnecessary mesh refinement in the
narrow channels between heatsink
fins.
12 Click OK.

Specifying Project Goals
Specify surface goals for maximum temperature on the CPU cover and mass flow rate for
the flows entering the rotating region and exiting from it. To select the necessary faces,
you will probably need to hide temporarily some components of the assembly.
GOAL TYPE GOAL VALUE FACE
Surface Goal Max Temperature of
Solid
Top face of the
CPU cover. To set
this goal you may
need to hide the
Heat Sink and
Copper Core
components.
Surface Goal Mass Flow Rate Top and side
surfaces of the
Rotation Region
component.
Surface Goal Mass Flow Rate Bottom face of
the
Rotation Region
component. To set
this goal you may
need to hide the
PCB component.
Equation goal ({SG Mass Flow Rate
1}+{SG Mass Flow
Rate 2})/{SG Mass
Flow Rate 1}
The disbalance of the inlet and outlet mass
flow rates. We are using the "+" operand
since the inlet and outlet mass flow rate
values have opposite signs.
Select No units for Dimensionality.
To calculate the thermal characterization parameter we will need the temperature of the
center of the CPU cover. To get more accurate value of the parameter we will specify a
separate point goal.
1 Click Flow Simulation, Insert, Point Goals.
2 Click Point Coordinates .
3 Enter the coordinates of the point: X = 0m, Y = 0.009675 m, Z = 0m.

13-10
4 Click Add Point .
5 In the Parameter table select the Value check box in the
Temperature of solid row.
6 Click OK .

Results
Use the goal plot tool to obtain the value of the temperature of the center of the CPU
cover. Now we can calculate the thermal characterization parameter of the heat sink:
= (329.9-311.15)/75 = 0.25 °C/W. The second most important
ΨCA = (TC – TA) ⁄ PD
characteristic of the CPU Cooler is the velocity of the flow above PCB. We can assess the
value of this parameter as well as the distribution of the temperature by looking at the cut
plots made in the Front and Right planes (see below).
Temperature field and velocity vectors distribution (Front plane, no offset, vector
spacing = 0.003 m, uniform plot, projected vectors, arrow size = 0.015 m).
Temperature field and velocity vectors distribution (Right plane, no offset, vector
spacing = 0.003 m, uniform plot, projected vectors, arrow size = 0.015 m).

13-12
Velocity distribution as a contour plot (Front plane, no offset).
Velocity distribution as a contour plot (Right plane, no offset).

Sw flowsimulation 2009 tutorial

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