fluent tutorials

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ANSYS FLUENT 12.0

Tutorial Guide

April 2009


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Copyright c 2009 by ANSYS, Inc.All Rights Reserved. No part of this document may be reproduced or otherwise used in

any form without express written permission from ANSYS, Inc.

Airpak, Mechanical APDL, Workbench, AUTODYN, CFX, FIDAP, FloWizard, FLUENT,

GAMBIT, Iceboard, Icechip, Icemax, Icepak, Icepro, Icewave, MixSim, POLYFLOW, TGrid,and any and all ANSYS, Inc. brand, product, service and feature names, logos andslogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries

located in the United States or other countries. All other brand, product, service andfeature names or trademarks are the property of their respective owners.

CATIA V5 is a registered trademark of Dassault Systemes. CHEMKIN is a registeredtrademark of Reaction Design Inc.

Portions of this program include material copyrighted by PathScale Corporation

2003-2004.

ANSYS, Inc. is certified to ISO 9001:2008

See the on-line documentation for the complete Legal Notices for ANSYS proprietarysoftware and third-party software. If you are unable to access the Legal Notice, contact

ANSYS, Inc.


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Contents

1 Introduction to Using ANSYS FLUENT: Fluid Flow andHeat Transfer in a Mixing Elbow 1-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3Step 1: Launching ANSYS FLUENT . . . . . . . . . . . . . . . . . . . . . 1-3

Step 2: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Step 3: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Step 4: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

Step 6: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 1-17Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

Step 9: Displaying the Preliminary Solution . . . . . . . . . . . . . . . . 1-29

Step 10: Enabling Second-Order Discretization . . . . . . . . . . . . . . . 1-39

Step 11: Adapting the Mesh . . . . . . . . . . . . . . . . . . . . . . . . . 1-45

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-55

2 Modeling Periodic Flow and Heat Transfer 2-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1



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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7


Step 6: Periodic Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 2-11

Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

3 Modeling External Compressible Flow 3-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6


Step 6: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31


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4 Modeling Transient Compressible Flow 4-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8



Step 7: Solution: Steady Flow . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Step 8: Enable Time Dependence and Set Transient Conditions . . . . . 4- 23

Step 9: Solution: Transient Flow . . . . . . . . . . . . . . . . . . . . . . 4-26

Step 10: Saving and Postprocessing Time-Dependent Data Sets . . . . . 4- 29

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-41


5 Modeling Radiation and Natural Convection 5-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

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Step 6: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16


Step 8: Compare the Contour Plots after Varying Radiating Surfaces . . 5-35

Step 9: S2S Definition, Solution and Postprocessing with PartialEnclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45


6 Using the Discrete Ordinates Radiation Model 6-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7



Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18


Step 9: Iterate for Higher Pixels . . . . . . . . . . . . . . . . . . . . . . . 6-27

Step 10: Iterate for Higher Divisions . . . . . . . . . . . . . . . . . . . . 6-31

Step 11: Make the Reflector Completely Diffuse . . . . . . . . . . . . . . 6-39

Step 12: Change the Boundary Type of Baffle . . . . . . . . . . . . . . . 6-40

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-41


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7 Using a Non-Conformal Mesh 7-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9




Step 8: Mesh Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22

Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-34


8 Modeling Flow Through Porous Media 8-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

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Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30


9 Using a Single Rotating Reference Frame 9-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1


Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7


Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 9-10Step 7: Solution Using the Standard k- Model . . . . . . . . . . . . . . 9-14

Step 8: Postprocessing for the Standard k- Solution . . . . . . . . . . . 9-21

Step 9: Solution Using the RNG k- Model . . . . . . . . . . . . . . . . . 9-27

Step 10: Postprocessing for the RNG k- Solution . . . . . . . . . . . . . 9-28

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33

10 Using Multiple Rotating Reference Frames 10-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2

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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7



Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-14


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21


11 Using the Mixing Plane Model 11-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1


Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6

Step 4: Mixing Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7

Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-9



Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-22


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Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-35


12 Using Sliding Meshes 12-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-6Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7




Step 8: Mesh Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15

Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-16

Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-30Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-35


13 Using Dynamic Meshes 13-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3


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Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-6


Step 6: Solution: Steady Flow . . . . . . . . . . . . . . . . . . . . . . . . 13-12

Step 7: Time-Dependent Solution Setup . . . . . . . . . . . . . . . . . . 13-15

Step 8: Mesh Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-17

Step 9: Time-Dependent Solution . . . . . . . . . . . . . . . . . . . . . . 13-24


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-33


14 Modeling Species Transport and Gaseous Combustion 14-1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1


Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2


Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3

Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-9


Step 6: Initial Solution with Constant Heat Capacity . . . . . . . . . . . 14- 19

Step 7: Solution with Varying Heat Capacity . . . . . . . . . . . . . . . . 1 4 - 2 4


Step 9: NOx Prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-34

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-44


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15 Using the Non-Premixed Combustion Model 15-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-4


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-7

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-14



Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-24


Step 9: Energy Balances Reporting . . . . . . . . . . . . . . . . . . . . . 15-32

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-34

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-34


16 Modeling Surface Chemistry 16-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-8

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Step 7: Non-Reacting Flow Solution . . . . . . . . . . . . . . . . . . . . . 16-22

Step 8: Reacting Flow Solution . . . . . . . . . . . . . . . . . . . . . . . 16-24


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-36


17 Modeling Evaporating Liquid Spray 17-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2

Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-9

Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 17-11Step 6: Initial Solution Without Droplets . . . . . . . . . . . . . . . . . . 17-17

Step 7: Create a Spray Injection . . . . . . . . . . . . . . . . . . . . . . . 17-24

Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-30


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-39


18 Using the VOF Model 18-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1


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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-4


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-8

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-9

Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-11


Step 7: User-Defined Function (UDF) . . . . . . . . . . . . . . . . . . . . 18-14


Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-19


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-25


19 Modeling Cavitation 19-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2

Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-7

Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-9



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Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-17


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-24


20 Using the Mixture and Eulerian Multiphase Models 20-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-3Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-3

Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-4

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-6

Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-7



Step 8: Solution Using the Mixture Model . . . . . . . . . . . . . . . . . 20-14Step 9: Postprocessing for the Mixture Solution . . . . . . . . . . . . . . 20-18

Step 10: Setup and Solution for the Eulerian Model . . . . . . . . . . . . 20-21

Step 11: Postprocessing for the Eulerian Model . . . . . . . . . . . . . . 20-25

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-27


21 Using the Eulerian Multiphase Model for Granular Flow 21-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1



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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-8

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10

Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12

Step 6: User-Defined Function (UDF) . . . . . . . . . . . . . . . . . . . . 21-15


Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-19


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-31


22 Modeling Solidification 22-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-5

Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-7



Step 7: Solution: Steady Conduction . . . . . . . . . . . . . . . . . . . . 22-18

Step 8: Solution: Transient Flow and Heat Transfer . . . . . . . . . . . . 22-26

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-34


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23 Using the Eulerian Granular Multiphase Model with Heat Transfer 23-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-3


Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-6

Step 4: UDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-7

Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8

Step 6: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-10


Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-21


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-32


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-32

24 Postprocessing 24-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-3


Step 3: Adding Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-5

Step 4: Creating Isosurfaces . . . . . . . . . . . . . . . . . . . . . . . . . 24-8

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Step 5: Contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-11

Step 6: Velocity Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-16

Step 7: Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-20

Step 8: Pathlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-25

Step 9: Overlaying Velocity Vectors on the Pathline Display . . . . . . . 24-30

Step 10: Exploded Views . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-32

Step 11: Animating the Display of Results in Successive StreamwisePlanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-37

Step 12: XY Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-40

Step 13: Annotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-42

Step 14: Saving Hardcopy Files . . . . . . . . . . . . . . . . . . . . . . . 24-44

Step 15: Volume Integral Reports . . . . . . . . . . . . . . . . . . . . . . 24-45Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-45

25 Turbo Postprocessing 25-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2

Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-3


Step 3: Defining the Turbomachinery Topology . . . . . . . . . . . . . . 25-4

Step 4: Isosurface Creation . . . . . . . . . . . . . . . . . . . . . . . . . . 25-7

Step 5: Contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-9

Step 6: Reporting Turbo Quantities . . . . . . . . . . . . . . . . . . . . . 25-14

Step 7: Averaged Contours . . . . . . . . . . . . . . . . . . . . . . . . . . 25-15

Step 8: 2D Contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-16

Step 9: Averaged XY Plots . . . . . . . . . . . . . . . . . . . . . . . . . 25-18

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-19

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26 Parallel Processing 26-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1

Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1



Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2

Step 1: Starting the Parallel Version of ANSYS FLUENT . . . . . . . . . 2 6 - 3

Step 1A: Multiprocessor Machine . . . . . . . . . . . . . . . . . . . . . . 26-3

Step 1B: Network of Computers . . . . . . . . . . . . . . . . . . . . . . . 26-5

Step 2: Reading and Partitioning the Mesh . . . . . . . . . . . . . . . . . 26-8

Step 3: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-13

Step 4: Checking Parallel Performance . . . . . . . . . . . . . . . . . . . 26-14


Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-17

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Using This Manual

Whats In This Manual

The ANSYS FLUENT Tutorial Guide contains a number of tutorials that teach you howto use ANSYS FLUENT to solve different types of problems. In each tutorial, featuresrelated to problem setup and postprocessing are demonstrated.

Tutorial 1 is a detailed tutorial designed to introduce the beginner to ANSYS FLUENT.This tutorial provides explicit instructions for all steps in the problem setup, solution, andpostprocessing. The remaining tutorials assume that you have read or solved Tutorial 1,or that you are already familiar with ANSYS FLUENT and its interface. In these tutorials,

some steps will not be shown explicitly.

All of the tutorials include some postprocessing instructions, but Tutorial 24 is devotedentirely to standard postprocessing, and Tutorial 25 is devoted to turbomachinery-specificpostprocessing.

Where to Find the Files Used in the Tutorials

Each of the tutorials uses an existing mesh file. (Tutorials for mesh generation areprovided with the mesh generator documentation.) You will find the appropriate meshfile (and any other relevant files used in the tutorial) on the User Services Center. The

Preparation step of each tutorial will tell you where to find the necessary files. (Notethat Tutorials 24, 25, and 26 use existing case and data files.)

Some of the more complex tutorials may require a significant amount of computationaltime. If you want to look at the results immediately, without waiting for the calculationto finish, you can find the case and data files associated with the tutorial on the UserServices Center (in the same directory where you found the mesh file).

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Using This Manual

How To Use This Manual

Depending on your familiarity with computational fluid dynamics and the ANSYS FLU-ENT software, you can use this tutorial guide in a variety of ways.

For the Beginner

If you are a beginning user ofANSYS FLUENT you should first read and solve Tutorial 1,in order to familiarize yourself with the interface and with basic setup and solutionprocedures. You may then want to try a tutorial that demonstrates features that youare going to use in your application. For example, if you are planning to solve a problemusing the non-premixed combustion model, you should look at Tutorial 15.

You may want to refer to other tutorials for instructions on using specific features, suchas custom field functions, mesh scaling, and so on, even if the problem solved in thetutorial is not of particular interest to you. To learn about postprocessing, you can lookat Tutorial 24, which is devoted entirely to postprocessing (although the other tutorials

all contain some postprocessing as well). For turbomachinery-specific postprocessing, seeTutorial 25.

For the Experienced User

If you are an experienced ANSYS FLUENT user, you can read and/or solve the tutorial(s)that demonstrate features that you are going to use in your application. For example,if you are planning to solve a problem using the non-premixed combustion model, youshould look at Tutorial 15.

You may want to refer to other tutorials for instructions on using specific features, such

as custom field functions, mesh scaling, and so on, even if the problem solved in thetutorial is not of particular interest to you. To learn about postprocessing, you can lookat Tutorial 24, which is devoted entirely to postprocessing (although the other tutorialsall contain some postprocessing as well). For turbomachinery-specific postprocessing, seeTutorial 25.

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Using This Manual

Typographical Conventions Used In This Manual

Several typographical conventions are used in the text of the tutorials to facilitate yourlearning process.

An informational icon ( ) marks an important note.

A warning icon ( ! ) marks a warning. Different type styles are used to indicate graphical user interface menu items and

text interface menu items (e.g., Zone Surface dialog box, surface/zone-surfacecommand).

The text interface type style is also used when illustrating exactly what appears onthe screen or exactly what you must type in the text window or in a dialog box.

Instructions for performing each step in a tutorial will appear in standard type.Additional information about a step in a tutorial appears in italicized type. A mini flow chart is used to guide you through the navigation pane, which leads

you to a specific task page or dialog box. For example,

Models Multiphase Edit...indicates that Models is selected in the navigation pane, which then opens thecorresponding task page. In the Models task page, Multiphase is selected from thelist. Clicking the Edit... button opens the Multiphase dialog box.

Also, a mini flow chart is used to indicate the menu selections that lead you to a

specific command or dialog box. For example,Define Injections...

indicates that the Injections... menu item can be selected from the Define pull-downmenu.

The words surrounded by boxes invoke menus (or submenus) and the arrows pointfrom a specific menu toward the item you should select from that menu.

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Using This Manual

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Tutorial 1. Introduction to Using ANSYS FLUENT: Fluid

Flow and Heat Transfer in a Mixing Elbow

Introduction

This tutorial illustrates the setup and solution of a three-dimensional turbulent fluidflow and heat transfer problem in a mixing elbow. The mixing elbow configurationis encountered in piping systems in power plants and process industries. It is oftenimportant to predict the flow field and temperature field in the area of the mixing regionin order to properly design the junction.

This tutorial demonstrates how to do the following:

Launch ANSYS FLUENT. Read an existing mesh file into ANSYS FLUENT. Use mixed units to define the geometry and fluid properties. Set material properties and boundary conditions for a turbulent forced convection

problem.

Initiate the calculation with residual plotting.

Calculate a solution using the pressure-based solver. Visually examine the flow and temperature fields using the postprocessing tools

available in ANSYS FLUENT.

Enable the second-order discretization scheme for improved prediction of the tem-perature field.

Adapt the mesh based on the temperature gradient to further improve the predic-tion of the temperature field.

Prerequisites

This tutorial assumes that you have little or no experience with ANSYS FLUENT, andso each step will be explicitly described.

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Introduction to Using ANSYS FLUENT: Fluid Flow and Heat Transfer in a Mixing Elbow

Problem Description

The problem to be considered is shown schematically in Figure 1.1. A cold fluid at 20Cflows into the pipe through a large inlet, and mixes with a warmer fluid at 40C thatenters through a smaller inlet located at the elbow. The pipe dimensions are in inches,and the fluid properties and boundary conditions are given in SI units. The Reynolds

number for the flow at the larger inlet is 50,800, so a turbulent flow model will be required.

Note: Since the geometry of the mixing elbow is symmetric, only half of the elbow needsto be modeled in ANSYS FLUENT.

= 4216 J/kgKpC

= 8 x 10 Pas4

k = 0.677 W/mK

= 0.4 m/sxU

4" Dia.

4"

8"

3"1" Dia.

1"

8"

Viscosity:Conductivity:

Specific Heat:

T = 20 C

I = 5%

= 1.2 m/syU

T = 40 C

I = 5%

Density: = 1000 kg/m3

o

o

Figure 1.1: Problem Specification

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Setup and Solution

Preparation

1. Download introduction.zip from the User Services Center to your working folder.This file can be found by using the Documentation link on the ANSYS FLUENT

product page.

2. Unzip introduction.zip.

The fileelbow.msh can be found in theintroduction folder created after unzippingthe file. Solution files created during the preparation of the tutorial are provided ina solution files folder.

Note: ANSYS FLUENT tutorials are prepared using ANSYS FLUENT on a Windows sys-tem. The screen shots and graphic images in the tutorials may be slightly differentthan the appearance on your system, depending on the operating system or graphicscard.

Step 1: Launching ANSYS FLUENT

1. Click the ANSYS FLUENT icon ( ) in the ANSYS program group to open FLU-ENT Launcher.

ANSYS FLUENT Launcher allows you to decide which version of ANSYS FLUENTyou will use, based on your geometry and on your processing capabilities.

2. Ensure that the proper options are enabled.

FLUENT Launcher retains settings from the previous session.

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(a) Select 3D from the Dimension list by clicking the radio button or the text, sothat a green dot appears in the radio button.

(b) Select Serial from the Processing Options list.

(c) Make sure that the Display Mesh After Reading, Embed Graphics Windows, andWorkbench Color Scheme options are enabled.

Note: An option is enabled when there is a check mark in the check box, anddisabled when the check box is empty. To change an option from disabledto enabled (or vice versa), click the check box or the text.

(d) Make sure that the Double-Precision option is disabled.

Extra: You can also restore the default settings by clicking the Default button.

3. Set the working path to the folder created when you unzipped introduction.zip.

(a) Click the Show More >> button.

(b) Enter the path to your working folder for Working Directory by double-clickingthe text box and typing.

Alternatively, you can click the browse button ( ) next to the WorkingDirectory text box and browse to the folder, using the Browse For Folder dialogbox.



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4. Click OK to launch ANSYS FLUENT.

Step 2: Mesh

1. Read the mesh file elbow.msh.File Read Mesh...

Select Read from the File menu, then select Mesh... to open the Select File dialogbox.



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(a) Select the mesh file by clicking elbow.msh in the introduction folder createdwhen you unzipped the original file.

(b) Click OK to read the file and close the Select File dialog box.

As the mesh file is read by ANSYS FLUENT, messages will appear in the consolereporting the progress of the conversion. ANSYS FLUENT will report that 13,852hexahedral fluid cells have been read, along with a number of boundary faces withdifferent zone identifiers.

Note: The mesh is displayed in the graphics window by default.

Extra: You can use the mouse to probe for mesh information in the graphics win-dow. If you click the right mouse button with the pointer on any node in themesh, information about the associated zone will be displayed in the console,including the name of the zone.

Alternatively, you can click the probe button ( ) in the graphics toolbar andclick the left mouse button on any node. This feature is especially useful when

you have several zones of the same type and you want to distinguish betweenthem quickly.

For this 3D problem, you can make it easier to probe particular nodes by chang-ing the view. You can perform any of the actions described in the followingtable:



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Table 1.1: View Manipulation Instructions

Action Using Default Mouse But-

ton Settings

Using Graphics Toolbar Buttons

Rotate view

(vertical,

horizontal)

Press the left mouse button

and drag the mouse. Release

the mouse button when the

viewing angle is satisfactory.

After clicking , press the left mouse but-

ton and drag the mouse. Dragging side to

side rotates the view about the vertical axis,

and up and down rotates the view about the

horizontal axis.

Roll view

(clock-

wise, coun-

terclock-

wise)

(not applicable) After clicking , press the left mouse but-

ton and drag the mouse side to side to roll the

view clockwise and counterclockwise.

Translateview

Press the middle mouse but-ton once at any point in the

display to center the view at

that point.

After clicking , press the left mouse but-ton and drag the mouse until the view is sat-

isfactory.

Zoom in on

view

Press the middle mouse but-

ton and drag the mouse to the

right and either up or down.

This action will cause a rect-

angle to appear in the display.

When you release the mouse

button, a new view will be dis-played which consists entirely

of the contents of the rectan-

gle.

After clicking , press the left mouse but-ton and drag the mouse to the right and upor down. This action will cause a rectangle toappear in the display. When you release themouse button, a new view will be displayedwhich consists entirely of the contents of the

rectangle.Alternatively, after clicking , press the

left mouse button and drag the mouse up.

Zoom out

from view

Press the middle mouse but-

ton and drag the mouse to the

right and either up or down.

This action will cause a rect-

angle to appear in the display.

When you release the mouse

button, a new view will be dis-played which consists entirely

of the contents of the rectan-

gle.

After clicking , press the left mouse but-ton and drag the mouse to the left and up ordown. This action will cause a rectangle toappear in the display. When you release themouse button, the magnification of the viewwill be reduced by an amount that is inversely

proportional to the size of the rectangle. Thenew view will be centered at the center of therectangle.

Alternatively, after clicking , press the

left mouse button and drag the mouse up.



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Note: After you have clicked a button in the graphics toolbar, you can return to

the default mouse button settings by clicking .

2. Manipulate the mesh display to obtain a front view as shown in Figure 1.2.

Graphics and Animations Views...Select Graphics and Animations in the navigation pane, then click Views... in theGraphics and Animations task page.

(a) Select front from the Views selection list.

Note: A list item is selected if it is highlighted, and deselected if it is nothighlighted.

(b) Click Apply and close the Views dialog box.

Figure 1.2: The Hexahedral Mesh for the Mixing Elbow



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Step 3: General Settings

Select General in the navigation pane to perform the mesh-related activities and to choosea solver.

General

1. Check the mesh.

General CheckANSYS FLUENT will report the results of the mesh check in the console.

Mesh Check

Domain Extents:

x-coordinate: min (m) = -8.000000e+000, max (m) = 8.000000e+000

y-coordinate: min (m) = -9.134633e+000, max (m) = 8.000000e+000

z-coordinate: min (m) = 0.000000e+000, max (m) = 2.000000e+000

Volume statistics:

minimum volume (m3): 5.098261e-004

maximum volume (m3): 2.330738e-002

total volume (m3): 1.607154e+002

Face area statistics:

minimum face area (m2): 4.865882e-003

maximum face area (m2): 1.017924e-001

Checking number of nodes per cell.

Checking number of faces per cell.



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Checking thread pointers.

Checking number of cells per face.

Checking face cells.

Checking cell connectivity.

Checking bridge faces.

Checking right-handed cells.

Checking face handedness.

Checking face node order.

Checking element type consistency.

Checking boundary types:

Checking face pairs.

Checking periodic boundaries.

Checking node count.

Checking nosolve cell count.

Checking nosolve face count.

Checking face children.

Checking cell children.

Checking storage.Done.

Note: The minimum and maximum values may vary slightly when running ondifferent platforms. The mesh check will list the minimum and maximum xand y values from the mesh in the default SI unit of meters. It will also reporta number of other mesh features that are checked. Any errors in the mesh willbe reported at this time. Ensure that the minimum volume is not negative,since ANSYS FLUENT cannot begin a calculation when this is the case.

2. Scale the mesh.

General Scale...



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(a) Make sure that Convert Units is selected in the Scaling group box.

(b) Select in from the Mesh Was Created In drop-down list by first clicking thedown-arrow button and then clicking the in item from the list that appears.

(c) Click Scale to scale the mesh.

! Be sure to click the Scale button only once.

Domain Extents will continue to be reported in the default SI unit of meters.

(d) Select in from the View Length Unit In drop-down list to set inches as theworking unit for length.

(e) Confirm that the domain extents are as shown in the previous dialog box.

(f) Close the Scale Mesh dialog box.

The mesh is now sized correctly and the working unit for length has been set toinches.

Note: Because the default SI units will be used for everything except length, thereis no need to change any other units in this problem. The choice of inches forthe unit of length has been made by the actions you have just taken. If youwant a different working unit for length, other than inches (e.g., millimeters),click Units... in theGeneral task page and make the appropriate change, in theSet Units dialog box.

3. Check the mesh.

General Check

Note: It is a good idea to check the mesh after you manipulate it (i.e., scale,convert to polyhedra, merge, separate, fuse, add zones, or smooth and swap).This will ensure that the quality of the mesh has not been compromised.

4. Retain the default settings in the Solver group box of the General task page.



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Step 4: Models

Models

1. Enable heat transfer by activating the energy equation.

Models Energy Edit...

(a) Enable the Energy Equation option.

(b) Click OK to close the Energy dialog box.



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2. Enable the k- turbulence model.

Models Viscous Edit...

(a) Select k-epsilon from the Model list.

The Viscous Model dialog box will expand.

(b) Select Realizable from the k-epsilon Model list.

(c) Click OK to accept the model and close the Viscous Model dialog box.



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Step 5: Materials

Materials

1. Create a new material called water.

Materials Fluid Create/Edit...



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(a) Enter water for Name.

(b) Enter the following values in the Properties group box:

Property Value

Density 1000 kg/m3

cp 4216 J/kg

KThermal Conductivity 0.677 W/mKViscosity 8e-04 kg/m s

(c) Click Change/Create.

A Question dialog box will open, asking if you want to overwrite air. Click Noso that the new materialwater is added to the list of materials which originallycontained only air.

Extra: You could have copied the material water-liquid (h2o) from thematerials database (accessed by clicking the FLUENT Database... button).If the properties in the database are different from those you wish to use,you can edit the values in the Properties group box in the Create/EditMaterials dialog box and click Change/Create to update your local copy.The original copy will not be affected.

(d) Make sure that there are now two materials (water and air) defined locally byexamining the FLUENT Fluid Materials drop-down list.

Both the materials will also be listed under Fluid in the Materials task page.

(e) Close the Create/Edit Materials dialog box.



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Step 6: Cell Zone Conditions

Cell Zone Conditions

1. Set the cell zone conditions for the fluid zone (fluid).

Cell Zone Conditions fluid Edit...



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(a) Select water from the Material Name drop-down list.

(b) Click OK to close the Fluid dialog box.

Step 7: Boundary Conditions

Boundary Conditions

1. Set the boundary conditions at the cold inlet (velocity-inlet-5).

Boundary Conditions velocity-inlet-5 Edit...Hint: If you are unsure of which inlet zone corresponds to the cold inlet, you can

probe the mesh display using the right mouse button or the probe toolbar button

( ) as described in a previous step. The information will be displayed in

the ANSYS FLUENT console, and the zone you probed will be automaticallyselected from the Zone selection list in the Boundary Conditions task page.



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(a) Select Components from the Velocity Specification Method drop-down list.

The Velocity Inlet dialog box will expand.

(b) Enter 0.4 m/s for X-Velocity.

(c) Retain the default value of 0 m/s for both Y-Velocity and Z-Velocity.

(d) Select Intensity and Hydraulic Diameter from the Specification Method drop-down list in the Turbulence group box.

(e) Enter 5% for Turbulent Intensity.

(f) Enter 4 inches for Hydraulic Diameter.

The hydraulic diameter Dh is defined as:

Dh =4A

Pw

where A is the cross-sectional area and Pw is the wetted perimeter.

(g) Click the Thermal tab.



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(h) Enter 293.15 K for Temperature.

(i) Click OK to close the Velocity Inlet dialog box.

2. In a similar manner, set the boundary conditions at the hot inlet ( velocity-inlet-6),using the values in the following table:

Boundary Conditions

velocity-inlet-6

Edit...

Velocity Specification Method ComponentsX-Velocity 0 m/sY-Velocity 1.2 m/sZ-Velocity 0 m/sSpecification Method Intensity & Hydraulic DiameterTurbulent Intensity 5%Hydraulic Diameter 1 inchTemperature 313.15 K



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3. Set the boundary conditions at the outlet (pressure-outlet-7), as shown in the Pres-sure Outlet dialog box.

Boundary Conditions pressure-outlet-7 Edit...

Note: ANSYS FLUENT will use the backflow conditions only if the fluid is flowinginto the computational domain through the outlet. Since backflow might occurat some point during the solution procedure, you should set reasonable backflowconditions to prevent convergence from being adversely affected.

4. For the wall of the pipe (wall), retain the default value of 0 W/m2 for Heat Flux inthe Thermal tab.

Boundary Conditions

wall

Edit...



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Step 8: Solution

In the steps that follow, you will set up and run the calculation using the task pages listedunder the Solution heading in the navigation pane.

1. Enable the plotting of residuals during the calculation.

Monitors Residuals Edit...

(a) Make sure that Plot is enabled in the Options group box.

(b) Enter 1e-05 for the Absolute Criteria of continuity, as shown in the ResidualMonitor dialog box.

(c) Click OK to close the Residual Monitors dialog box.

Note: By default, all variables will be monitored and checked by ANSYS FLUENTas a means to determine the convergence of the solution. It is a good practiceto also define a surface monitor that can help evaluate whether the solution istruly converged. You will do this in the next step.



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2. Define a surface monitor at the outlet (pressure-outlet-7).

Monitors Create... (Surface Monitors)

(a) Retain the default entry of surf-mon-1 for the Name of the surface monitor.

(b) Enable the Plot and Write options for surf-mon-1.

(c) Retain the default entry of surf-mon-1.out for File Name.

(d) Set Get Data Every to 3 by clicking the up-arrow button.

This setting instructsANSYS FLUENT to update the plot of the surface monitorand write data to a file after every 3 iterations during the solution.

(e) Select Mass-Weighted Average from the Report Type drop-down list.

(f) Select Temperature... and Static Temperature from the Field Variable drop-downlists.

(g) Select pressure-outlet-7 from the Surfaces selection list.

(h) Click OK to save the surface monitor settings and close the Surface Monitordialog box.

The name and report type of the surface monitor you created will be displayed inthe Surface Monitors selection list in the Monitors task page.



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3. Initialize the flow field, using the boundary conditions settings at the cold inlet(velocity-inlet-5) as a starting point.

Solution Initialization

(a) Select velocity-inlet-5 from the Compute from drop-down list.

(b) Enter 1.2 m/s for Y Velocity in the Initial Values group box.

Note: While an initial X Velocity is an appropriate guess for the horizontalsection, the addition of a Y Velocity component will give rise to a betterinitial guess throughout the entire elbow.

(c) Click Initialize.



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4. Check to see if the case conforms to best practices.

Run Calculation Check Case

(a) Click the Solver tab and examine the Recommendation in the Manual Imple-mentation group box.

The only recommendation for this case file is to use discretization of a higherorder. This recommendation can be ignored for the time being, as it will beperformed in a later step.

(b) Close the Case Check dialog box.

5. Save the case file (elbow1.cas.gz).

File Write Case...



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(a) (optional) Indicate the folder in which you would like the file to be saved.

By default, the file will be saved in the folder from which you read inelbow.msh(i.e., the introduction folder). You can indicate a different folder by brows-ing to it or by creating a new folder.

(b) Enter elbow1.cas.gz for Case File.

Adding the extension.gz to the end of the file name extension instructs ANSYSFLUENT to save the file in a compressed format. You do not have to include.cas in the extension (e.g., if you enter elbow1.gz, ANSYS FLUENT willautomatically save the file as elbow1.cas.gz). The.gz extension can also beused to save data files in a compressed format.

(c) Make sure that the default Write Binary Files option is enabled, so that a binaryfile will be written.

(d) Click OK to save the case file and close the Select File dialog box.

6. Start the calculation by requesting 150 iterations.

Run Calculation

(a) Enter 150 for Number of Iterations.

(b) Click Calculate.

Note: By starting the calculation, you are also starting to save the surfacemonitor data at the rate specified in the Surface monitors dialog box. If a

file already exists in your working folder with the name you specified intheDefine Surface Monitor dialog box, then a Question dialog box will open,asking if you would like to append the new data to the existing file. ClickNo in theQuestion dialog box, and then click OK in theWarning dialog boxthat follows to overwrite the existing file.



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Figure 1.3: Convergence History of the Mass-Weighted Average Temperature

Note: The solution will be stopped by ANSYS FLUENT after approximately140 iterations, when the residuals reach their specified values. The ex-act number of iterations will vary, depending on the platform being used.An Information dialog box will open to alert you that the calculation iscomplete. Click O

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