Fluent Tutorials 1

ANSYS FLUENT 12.0 Tutorial Guide

April 2009

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 and slogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries located in the United States or other countries. All other brand, product, service and feature names or trademarks are the property of their respective owners. CATIA V5 is a registered trademark of Dassault Syst`mes. CHEMKIN is a registered e trademark of Reaction Design Inc. Portions of this program include material copyrighted by PathScale Corporation 2003-2004.

ANSYS, Inc. is certied to ISO 9001:2008

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

Contents

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

1-1 1-1 1-1 1-2 1-3 1-3 1-3 1-5 1-9

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Launching ANSYS FLUENT . . . . . . . . . . . . . . . . . . . . . Step 2: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . .

Step 4: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12 Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14 Step 6: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 1-16 Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 1-17 Step 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 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 2-1 2-1 2-2 2-3

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Release 12.0 c ANSYS, Inc. March 12, 2009

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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . .

2-3 2-3 2-6 2-6 2-7 2-9

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 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3-1 3-1 3-2 3-2 3-2 3-2 3-4 3-5 3-6 3-7 3-9

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . Step 6: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . .

Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31

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4 Modeling Transient Compressible Flow Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-1 4-1 4-1 4-2 4-2 4-2 4-3 4-5 4-6 4-8 4-9

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . .

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 4-10 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 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-41 5 Modeling Radiation and Natural Convection Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 5-1 5-1 5-1 5-2 5-2 5-2 5-3 5-4 5-8

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 5-10 Step 6: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16 Step 7: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23 Step 8: Compare the Contour Plots after Varying Radiating Surfaces . . 5-35 Step 9: S2S Denition, Solution and Postprocessing with Partial Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45 6 Using the Discrete Ordinates Radiation Model Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 6-1 6-1 6-1 6-2 6-2 6-3 6-3 6-5 6-7 6-9

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . .

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 6-11 Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21 Step 9: Iterate for Higher Pixels . . . . . . . . . . . . . . . . . . . . . . . 6-27 Step 10: Iterate for Higher Divisions . . . . . . . . . . . . . . . . . . . . 6-31 Step 11: Make the Reector Completely Diuse . . . . . . . . . . . . . . 6-39 Step 12: Change the Boundary Type of Bae . . . . . . . . . . . . . . . 6-40 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-41 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-41

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7 Using a Non-Conformal Mesh Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-1 7-1 7-1 7-2 7-3 7-3 7-3 7-7 7-7 7-9


Step 5: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 7-10 Step 6: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 7-11 Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 7-12 Step 8: Mesh Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21 Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22 Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-34 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-34 8 Modeling Flow Through Porous Media Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 8-1 8-1 8-2 8-2 8-2 8-3 8-4 8-5 8-6



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Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . .

8-8

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 8-11 Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30 9 Using a Single Rotating Reference Frame Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 9-1 9-1 9-1 9-3 9-3 9-3 9-3 9-6 9-7 9-8

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . .

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 9-10 Step 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 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33 10 Using Multiple Rotating Reference Frames 10-1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2

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Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7 Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 10-8 Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 10-10 Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-14 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-18 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21 11 Using the Mixing Plane Model 11-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-6 Step 4: Mixing Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7 Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-9 Step 6: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 11-10 Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 11-13 Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-22 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-29


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Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-35 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-35 12 Using Sliding Meshes 12-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-6 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7 Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 12-8 Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 12-11 Step 7: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 12-14 Step 8: Mesh Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15 Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-16 Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-30 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-35 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-35 13 Using Dynamic Meshes 13-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3

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Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-6 Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 13-8 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 Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-31 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-33 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-33 14 Modeling Species Transport and Gaseous Combustion 14-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-9 Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 14-13 Step 6: Initial Solution with Constant Heat Capacity . . . . . . . . . . . 14-19 Step 7: Solution with Varying Heat Capacity . . . . . . . . . . . . . . . . 14-24 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-26 Step 9: NOx Prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-34 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-44 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-44


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15 Using the Non-Premixed Combustion Model

15-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-4 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-4 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-7 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-14 Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 15-15 Step 6: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 15-23 Step 7: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-24 Step 8: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-29 Step 9: Energy Balances Reporting . . . . . . . . . . . . . . . . . . . . . 15-32 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-34 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-34 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-34 16 Modeling Surface Chemistry 16-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-6 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-8

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Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 16-16 Step 6: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 16-21 Step 7: Non-Reacting Flow Solution . . . . . . . . . . . . . . . . . . . . . 16-22 Step 8: Reacting Flow Solution . . . . . . . . . . . . . . . . . . . . . . . 16-24 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-30 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-36 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-36 17 Modeling Evaporating Liquid Spray 17-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-6 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-9 Step 5: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 17-11 Step 6: Initial Solution Without Droplets . . . . . . . . . . . . . . . . . . 17-17 Step 7: Create a Spray Injection . . . . . . . . . . . . . . . . . . . . . . . 17-24 Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-30 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-36 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-39 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-39 18 Using the VOF Model 18-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1


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Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-4 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-6 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-8 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-9 Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-11

Step 6: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 18-13 Step 7: User-Dened Function (UDF) . . . . . . . . . . . . . . . . . . . . 18-14 Step 8: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 18-15 Step 9: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-19 Step 10: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-24 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-25 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-25 19 Modeling Cavitation 19-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-5 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-7 Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-9

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 19-12 Step 7: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 19-16

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Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-17 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-21 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-24 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-24 20 Using the Mixture and Eulerian Multiphase Models 20-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-4 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-6 Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-7

Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 20-9 Step 7: Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . 20-13 Step 8: Solution Using the Mixture Model . . . . . . . . . . . . . . . . . 20-14 Step 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 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-27 21 Using the Eulerian Multiphase Model for Granular Flow 21-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2


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Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-8 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-10 Step 5: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-12

Step 6: User-Dened Function (UDF) . . . . . . . . . . . . . . . . . . . . 21-15 Step 7: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 21-16 Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-19 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-29 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-31 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-31 22 Modeling Solidication 22-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-5 Step 4: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-7 Step 5: Cell Zone Conditions . . . . . . . . . . . . . . . . . . . . . . . . . 22-9 Step 6: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 22-10 Step 7: Solution: Steady Conduction . . . . . . . . . . . . . . . . . . . . 22-18 Step 8: Solution: Transient Flow and Heat Transfer . . . . . . . . . . . . 22-26 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-34 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-34

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

Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-3 Step 3: Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-6 Step 4: UDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-7

Step 5: Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-8 Step 6: Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-10

Step 7: Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . 23-13 Step 8: Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-21 Step 9: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-30 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-32 Further Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-32 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-32 24 Postprocessing 24-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 Streamwise Planes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 24-45 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-45 25 Turbo Postprocessing 25-1


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-2 Step 1: Mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-3 Step 2: General Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-3 Step 3: Dening 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


Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1 Setup and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2 Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-2 Step 1: Starting the Parallel Version of ANSYS FLUENT . . . . . . . . . 26-3 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 Step 5: Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-15 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-17


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Using This ManualWhats In This ManualThe ANSYS FLUENT Tutorial Guide contains a number of tutorials that teach you how to use ANSYS FLUENT to solve dierent types of problems. In each tutorial, features related 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, and postprocessing. 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 devoted entirely to standard postprocessing, and Tutorial 25 is devoted to turbomachinery-specic postprocessing.

Where to Find the Files Used in the TutorialsEach of the tutorials uses an existing mesh le. (Tutorials for mesh generation are provided with the mesh generator documentation.) You will nd the appropriate mesh le (and any other relevant les used in the tutorial) on the User Services Center. The Preparation step of each tutorial will tell you where to nd the necessary les. (Note that Tutorials 24, 25, and 26 use existing case and data les.) Some of the more complex tutorials may require a signicant amount of computational time. If you want to look at the results immediately, without waiting for the calculation to nish, you can nd the case and data les associated with the tutorial on the User Services Center (in the same directory where you found the mesh le).


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Using This Manual

How To Use This ManualDepending on your familiarity with computational uid dynamics and the ANSYS FLUENT software, you can use this tutorial guide in a variety of ways.

For the BeginnerIf you are a beginning user of ANSYS FLUENT you should rst read and solve Tutorial 1, in order to familiarize yourself with the interface and with basic setup and solution procedures. You may then want to try a tutorial that demonstrates 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, you should look at Tutorial 15. You may want to refer to other tutorials for instructions on using specic features, such as custom eld functions, mesh scaling, and so on, even if the problem solved in the tutorial is not of particular interest to you. To learn about postprocessing, you can look at Tutorial 24, which is devoted entirely to postprocessing (although the other tutorials all contain some postprocessing as well). For turbomachinery-specic postprocessing, see Tutorial 25.

For the Experienced UserIf 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, you should look at Tutorial 15. You may want to refer to other tutorials for instructions on using specic features, such as custom eld functions, mesh scaling, and so on, even if the problem solved in the tutorial is not of particular interest to you. To learn about postprocessing, you can look at Tutorial 24, which is devoted entirely to postprocessing (although the other tutorials all contain some postprocessing as well). For turbomachinery-specic postprocessing, see Tutorial 25.

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Using This Manual

Typographical Conventions Used In This ManualSeveral typographical conventions are used in the text of the tutorials to facilitate your learning process.

An informational icon ( A warning icon (

) marks an important note.

! ) marks a warning.

Dierent type styles are used to indicate graphical user interface menu items and text interface menu items (e.g., Zone Surface dialog box, surface/zone-surface command). The text interface type style is also used when illustrating exactly what appears on the 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 ow chart is used to guide you through the navigation pane, which leads you to a specic task page or dialog box. For example, Models Multiphase Edit... indicates that Models is selected in the navigation pane, which then opens the corresponding task page. In the Models task page, Multiphase is selected from the list. Clicking the Edit... button opens the Multiphase dialog box. Also, a mini ow chart is used to indicate the menu selections that lead you to a specic command or dialog box. For example, Dene Injections... indicates that the Injections... menu item can be selected from the Dene pull-down menu. The words surrounded by boxes invoke menus (or submenus) and the arrows point from a specic 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 ElbowIntroductionThis tutorial illustrates the setup and solution of a three-dimensional turbulent uid ow and heat transfer problem in a mixing elbow. The mixing elbow conguration is encountered in piping systems in power plants and process industries. It is often important to predict the ow eld and temperature eld in the area of the mixing region in order to properly design the junction. This tutorial demonstrates how to do the following: Launch ANSYS FLUENT. Read an existing mesh le into ANSYS FLUENT. Use mixed units to dene the geometry and uid 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 ow and temperature elds using the postprocessing tools available in ANSYS FLUENT. Enable the second-order discretization scheme for improved prediction of the temperature eld. Adapt the mesh based on the temperature gradient to further improve the prediction of the temperature eld.

PrerequisitesThis tutorial assumes that you have little or no experience with ANSYS FLUENT, and so 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 DescriptionThe problem to be considered is shown schematically in Figure 1.1. A cold uid at 20 C ows into the pipe through a large inlet, and mixes with a warmer uid at 40 C that enters through a smaller inlet located at the elbow. The pipe dimensions are in inches, and the uid properties and boundary conditions are given in SI units. The Reynolds number for the ow at the larger inlet is 50,800, so a turbulent ow model will be required. Note: Since the geometry of the mixing elbow is symmetric, only half of the elbow needs to be modeled in ANSYS FLUENT.

Density: Viscosity: Conductivity: Specific Heat:

k Cp

= = = =

1000 kg/m3 8 x 10 4 Pas 0.677 W/mK 4216 J/kgK

8"

4"

Ux = 0.4 m/s T = 20oC I = 5%

4" Dia. 3" 8"

1"

1" Dia. Uy = 1.2 m/s T = 40oC I = 5%

Figure 1.1: Problem Specication

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Setup and Solution Preparation1. Download introduction.zip from the User Services Center to your working folder. This le can be found by using the Documentation link on the ANSYS FLUENT product page. 2. Unzip introduction.zip. The le elbow.msh can be found in the introduction folder created after unzipping the le. Solution les created during the preparation of the tutorial are provided in a solution files folder. Note: ANSYS FLUENT tutorials are prepared using ANSYS FLUENT on a Windows system. The screen shots and graphic images in the tutorials may be slightly dierent than the appearance on your system, depending on the operating system or graphics card.

Step 1: Launching ANSYS FLUENT1. Click the ANSYS FLUENT icon ( ENT Launcher. ) in the ANSYS program group to open FLU-

ANSYS FLUENT Launcher allows you to decide which version of ANSYS FLUENT you 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, so that 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, and Workbench Color Scheme options are enabled. Note: An option is enabled when there is a check mark in the check box, and disabled when the check box is empty. To change an option from disabled to 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-clicking the text box and typing. Alternatively, you can click the browse button ( ) next to the Working Directory text box and browse to the folder, using the Browse For Folder dialog box.

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4. Click OK to launch ANSYS FLUENT.

Step 2: Mesh1. Read the mesh le elbow.msh. File Read Mesh... Select Read from the File menu, then select Mesh... to open the Select File dialog box.


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(a) Select the mesh le by clicking elbow.msh in the introduction folder created when you unzipped the original le. (b) Click OK to read the le and close the Select File dialog box. As the mesh le is read by ANSYS FLUENT, messages will appear in the console reporting the progress of the conversion. ANSYS FLUENT will report that 13,852 hexahedral uid cells have been read, along with a number of boundary faces with dierent zone identiers. 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 window. If you click the right mouse button with the pointer on any node in the mesh, 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 and click 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 between them quickly. For this 3D problem, you can make it easier to probe particular nodes by changing the view. You can perform any of the actions described in the following table:

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Table 1.1: View Manipulation Instructions Action Using Default Mouse Button Settings Using Graphics Toolbar ButtonsAfter clicking , press the left mouse button 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. After clicking , press the left mouse button and drag the mouse side to side to roll the view clockwise and counterclockwise.

Rotate view Press the left mouse button (vertical, and drag the mouse. Release horizontal) the mouse button when the viewing angle is satisfactory.

Roll view (clockwise, counterclockwise) Translate view

(not applicable)

Press the middle mouse button once at any point in the display to center the view at that point. Press the middle mouse button and drag the mouse to the right and either up or down. This action will cause a rectangle to appear in the display. When you release the mouse button, a new view will be displayed which consists entirely of the contents of the rectangle. Press the middle mouse button and drag the mouse to the right and either up or down. This action will cause a rectangle to appear in the display. When you release the mouse button, a new view will be displayed which consists entirely of the contents of the rectangle.

After clicking , press the left mouse button and drag the mouse until the view is satisfactory.

Zoom in on view

After clicking , press the left mouse button and drag the mouse to the right and up or down. This action will cause a rectangle to appear in the display. When you release the mouse button, a new view will be displayed which consists entirely of the contents of the rectangle. Alternatively, after clicking , press the left mouse button and drag the mouse up. After clicking , press the left mouse button and drag the mouse to the left and up or down. This action will cause a rectangle to appear in the display. When you release the mouse button, the magnication of the view will be reduced by an amount that is inversely proportional to the size of the rectangle. The new view will be centered at the center of the rectangle. Alternatively, after clicking , press the left mouse button and drag the mouse up.

Zoom out from view


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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 the Graphics 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 not highlighted. (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 SettingsSelect General in the navigation pane to perform the mesh-related activities and to choose a solver. General

1. Check the mesh. General Check ANSYS 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 Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Done.

thread pointers. number of cells per face. face cells. cell connectivity. bridge faces. right-handed cells. face handedness. face node order. element type consistency. boundary types: face pairs. periodic boundaries. node count. nosolve cell count. nosolve face count. face children. cell children. storage.

Note: The minimum and maximum values may vary slightly when running on dierent platforms. The mesh check will list the minimum and maximum x and y values from the mesh in the default SI unit of meters. It will also report a number of other mesh features that are checked. Any errors in the mesh will be 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 rst clicking the down-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 the working unit for length. (e) Conrm 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 to inches. Note: Because the default SI units will be used for everything except length, there is no need to change any other units in this problem. The choice of inches for the unit of length has been made by the actions you have just taken. If you want a dierent working unit for length, other than inches (e.g., millimeters), click Units... in the General task page and make the appropriate change, in the Set 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: ModelsModels

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: MaterialsMaterials

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 Density cp Thermal Conductivity Viscosity (c) Click Change/Create. A Question dialog box will open, asking if you want to overwrite air. Click No so that the new material water is added to the list of materials which originally contained only air. Value 1000 kg/m3 4216 J/kg K 0.677 W/m K 8e-04 kg/m s

Extra: You could have copied the material water-liquid (h2o) from the materials database (accessed by clicking the FLUENT Database... button). If the properties in the database are dierent from those you wish to use, you can edit the values in the Properties group box in the Create/Edit Materials dialog box and click Change/Create to update your local copy. The original copy will not be aected. (d) Make sure that there are now two materials (water and air) dened locally by examining 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 ConditionsCell Zone Conditions

1. Set the cell zone conditions for the uid zone (uid). Cell Zone Conditions uid 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 ConditionsBoundary 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 automatically selected from the Zone selection list in the Boundary Conditions task page.


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(a) Select Components from the Velocity Specication 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 Specication Method dropdown list in the Turbulence group box. (e) Enter 5% for Turbulent Intensity. (f) Enter 4 inches for Hydraulic Diameter. The hydraulic diameter Dh is dened 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... Components 0 m/s 1.2 m/s 0 m/s Intensity & Hydraulic Diameter 5% 1 inch 313.15 K

Velocity Specication Method X-Velocity Y-Velocity Z-Velocity Specication Method Turbulent Intensity Hydraulic Diameter Temperature


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3. Set the boundary conditions at the outlet (pressure-outlet-7), as shown in the Pressure Outlet dialog box. Boundary Conditions pressure-outlet-7 Edit...

Note: ANSYS FLUENT will use the backow conditions only if the uid is owing into the computational domain through the outlet. Since backow might occur at some point during the solution procedure, you should set reasonable backow conditions to prevent convergence from being adversely aected. 4. For the wall of the pipe (wall), retain the default value of 0 W/m2 for Heat Flux in the Thermal tab. Boundary Conditions wall Edit...

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Step 8: SolutionIn the steps that follow, you will set up and run the calculation using the task pages listed under 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 Residual Monitor dialog box. (c) Click OK to close the Residual Monitors dialog box. Note: By default, all variables will be monitored and checked by ANSYS FLUENT as a means to determine the convergence of the solution. It is a good practice to also dene a surface monitor that can help evaluate whether the solution is truly converged. You will do this in the next step.


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2. Dene 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 instructs ANSYS FLUENT to update the plot of the surface monitor and write data to a le 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-down lists. (g) Select pressure-outlet-7 from the Surfaces selection list. (h) Click OK to save the surface monitor settings and close the Surface Monitor dialog box. The name and report type of the surface monitor you created will be displayed in the Surface Monitors selection list in the Monitors task page.

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3. Initialize the ow eld, 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 horizontal section, the addition of a Y Velocity component will give rise to a better initial 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 Implementation group box. The only recommendation for this case le is to use discretization of a higher order. This recommendation can be ignored for the time being, as it will be performed in a later step. (b) Close the Case Check dialog box. 5. Save the case le (elbow1.cas.gz). File Write Case...

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(a) (optional) Indicate the folder in which you would like the le to be saved. By default, the le will be saved in the folder from which you read in elbow.msh (i.e., the introduction folder). You can indicate a dierent folder by browsing 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 le name extension instructs ANSYS FLUENT to save the le in a compressed format. You do not have to include .cas in the extension (e.g., if you enter elbow1.gz, ANSYS FLUENT will automatically save the le as elbow1.cas.gz). The .gz extension can also be used to save data les in a compressed format. (c) Make sure that the default Write Binary Files option is enabled, so that a binary le will be written. (d) Click OK to save the case le 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 surface monitor data at the rate specied in the Surface monitors dialog box. If a le already exists in your working folder with the name you specied in the Dene Surface Monitor dialog box, then a Question dialog box will open, asking if you would like to append the new data to the existing le. Click No in the Question dialog box, and then click OK in the Warning dialog box that follows to overwrite the existing le.


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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 approximately 140 iterations, when the residuals reach their specied values. The exact number of iterations will vary, depending on the platform being used. An Information dialog box will open to alert you that the calculation is complete. Click OK in the Information dialog box to proceed. Since the residual values vary slightly by platform, the plot that appears on your screen may not be exactly the same as the one shown here. As the calculation progresses, the residuals will be plotted in the graphics window (Figure 1.4).

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You can display the residuals history (Figure 1.4), by selecting it from the graphics window drop-down list.Residuals continuity x-velocity y-velocity z-velocity energy k epsilon

1e+01 1e+00 1e-01 1e-02 1e-03 1e-04 1e-05 1e-06 1e-07 0 20 40 60 80 100 120 140

Iterations

Scaled Residuals

FLUENT 12.0 (3d, pbns, rke)

Figure 1.4: Residuals for the First 140 Iterations 7. Examine the plots for convergence (Figures 1.4 and 1.3). Note: There are no universal metrics for judging convergence. Residual denitions that are useful for one class of problem are sometimes misleading for other classes of problems. Therefore it is a good idea to judge convergence not only by examining residual levels, but also by monitoring relevant integrated quantities and checking for mass and energy balances. There are three indicators that convergence has been reached: The residuals have decreased to a sucient degree. The solution has converged when the Convergence Criterion for each variable has been reached. The default criterion is that each residual will be reduced to a value of less than 103 , except the energy residual, for which the default criterion is 106 . The solution no longer changes with more iterations. Sometimes the residuals may not fall below the convergence criterion set in the case setup. However, monitoring the representative ow variables through iterations may show that the residuals have stagnated and do not change with further iterations. This could also be considered as convergence.


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The overall mass, momentum, energy, and scalar balances are obtained. You can examine the overall mass, momentum, energy and scalar balances in the Flux Reports dialog box. The net imbalance should be less than 0.2% of the net ux through the domain when the solution has converged. In the next step you will check to see if the mass balance indicates convergence. 8. Examine the mass ux report for convergence. Reports Fluxes Set Up...

(a) Make sure that Mass Flow Rate is selected from the Options list. (b) Select pressure-outlet-7, velocity-inlet-5, and velocity-inlet-6 from the Boundaries selection list. (c) Click Compute. The individual and net results of the computation will be displayed in the Results and Net Results boxes, respectively, in the Flux Reports dialog box, as well as in the console. The sum of the ux for the inlets should be very close to the sum of the ux for the outlets. The net results show that the imbalance in this case is well below the 0.2% criteria suggested previously. (d) Close the Flux Reports dialog box. 9. Save the data le (elbow1.dat.gz). File Write Data... In later steps of this tutorial you will save additional case and data les with different prexes.

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Step 9: Displaying the Preliminary SolutionIn the steps that follow, you will visualize various aspects of the ow for the preliminary solution, using the task pages listed under the Results heading in the navigation pane. 1. Display lled contours of velocity magnitude on the symmetry plane (Figure 1.5). Graphics and Animations Contours Set Up...

(a) Enable Filled in the Options group box. (b) Make sure that Node Values is enabled in the Options group box. (c) Select Velocity... and Velocity Magnitude from the Contours of drop-down lists. (d) Select symmetry from the Surfaces selection list. (e) Click Display to display the contours in the active graphics window. Extra: When you probe a point in the displayed domain with the mouse, the level of the corresponding contour is highlighted in the colormap in the graphics window, and is also reported in the console.


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Figure 1.5: Predicted Velocity Distribution after the Initial Calculation

2. Display lled contours of temperature on the symmetry plane (Figure 1.6). Graphics and Animations Contours Set Up...

(a) Select Temperature... and Static Temperature from the Contours of drop-down lists.

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(b) Click Display and close the Contours dialog box.

Figure 1.6: Predicted Temperature Distribution after the Initial Calculation

3. Display velocity vectors on the symmetry plane (Figures 1.7 and 1.8). Graphics and Animations Vectors Set Up...


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(a) Select symmetry from the Surfaces selection list. (b) Click Display to plot the velocity vectors. Note: The Auto Scale option is enabled by default in the Options group box. This scaling sometimes creates vectors that are too small or too large in the majority of the domain. You can improve the clarity by adjusting the Scale and Skip settings, thereby changing the size and number of the vectors when they are displayed. (c) Enter 4 for Scale. (d) Set Skip to 2. (e) Click Display again to redisplay the vectors (Figure 1.7).

Figure 1.7: Resized Velocity Vectors (f) Close the Vectors dialog box. (g) Zoom in on the vectors in the display. To zoom in, refer to Table 1.1. The image will be redisplayed at a higher magnication (Figure 1.8).

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Figure 1.8: Magnied View of Velocity Vectors (h) Zoom out to the original view. To zoom out or translate the view refer Table 1.1. The image will be redisplayed at a lower magnication (Figure 1.7). You also have the option of selecting the original view in the Views dialog box: select front from the Views selection list and click Apply. Graphics and Animations Views...


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4. Create a line surface at the centerline of the outlet. Surface Iso-Surface...

(a) Select Mesh... and Z-Coordinate from the Surface of Constant drop-down lists. (b) Click Compute. The range of values in the z direction will be displayed in the Min and Max boxes. (c) Retain the default value of 0 inches for Iso-Values. (d) Select pressure-outlet-7 from the From Surface selection list. (e) Enter z=0 outlet for New Surface Name. (f) Click Create. After the line surface z=0 outlet is created, a new entry will automatically be generated for New Surface Name, in case you would like to create another surface. (g) Close the Iso-Surface dialog box.

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5. Display and save an XY plot of the temperature prole across the centerline of the outlet for the initial solution (Figure 1.9). Plots XY Plot Set Up...

(a) Select Temperature... and Static Temperature from the Y Axis Function dropdown lists. (b) Select z=0 outlet from the Surfaces selection list. (c) Click Plot. (d) Enable Write to File in the Options group box. The button that was originally labeled Plot will change to Write.... (e) Click Write... to open the Select File dialog box. i. Enter outlet temp1.xy for XY File. ii. Click OK to save the temperature data and close the Select File dialog box. (f) Close the Solution XY Plot dialog box.


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Figure 1.9: Outlet Temperature Prole for the Initial Solution

6. Dene a custom eld function for the dynamic head formula (|V |2 /2). Dene Custom Field Functions...

(a) Select Density... and Density from the Field Functions drop-down lists, and click the Select button to add density to the Denition eld. (b) Click the X button to add the multiplication symbol to the Denition eld. (c) Select Velocity... and Velocity Magnitude from the Field Functions drop-down lists, and click the Select button to add |V| to the Denition eld.

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(d) Click y^x to raise the last entry in the Denition eld to a power, and click 2 for the power. (e) Click the / button to add the division symbol to the Denition eld, and then click 2. (f) Enter dynamic-head for New Function Name. (g) Click Dene and close the Custom Field Function Calculator dialog box. 7. Display lled contours of the custom eld function (Figure 1.10). Graphics and Animations Contours Set Up...

(a) Select Custom Field Functions... and dynamic-head from the Contours of dropdown lists. Hint: Custom Field Functions... is at the top of the upper Contours of dropdown list. After you have opened the drop-down list, scroll up by clicking the up-arrow button on the scroll bar on the right. (b) Make sure that symmetry is selected from the Surfaces selection list. (c) Click Display and close the Contours dialog box. Note: You may need to change the view by zooming out after the last vector display, if you have not already done so.


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Figure 1.10: Contours of the Dynamic Head Custom Field Function

8. Save the settings for the custom eld function by writing the case and data les (elbow1.cas.gz and elbow1.dat.gz). File Write Case & Data... (a) Ensure that elbow1.cas.gz is entered for Case/Data File. Note: When you write the case and data le at the same time, it does not matter whether you specify the le name with a .cas or .dat extension, as both will be saved. (b) Click OK to save the les and close the Select File dialog box.

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Step 10: Enabling Second-Order DiscretizationThe elbow solution computed in the rst part of this tutorial uses rst-order discretization. The resulting solution is very diusive; mixing is overpredicted, as can be seen in the contour plots of temperature and velocity distribution. You will now change to secondorder discretization for all listed equations. 1. Change the solver settings. Solution Methods

(a) Select Second Order from the Pressure drop-down list. (b) Select Second Order Upwind from the Momentum, Turbulent Kinetic Energy, Turbulent Dissipation Rate, and Energy drop-down lists. You will need to scroll the Spatial Discretization group box down to nd Energy. 2. (optional) Check the case to conrm that there are no recommendations for revisions to the setup. Run Calculation Check Case


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3. Continue the calculation by requesting 150 more iterations. Run Calculation

Extra: To save the convergence history of the surface monitor for this set of iterations as a separate output le, you would need to change the File Name in the Surface Monitor dialog box to surf-mon-2.out prior to running the calculation. (a) Make sure that 150 is entered for Number of Iterations. (b) Click Calculate. The solution will converge in approximately 63 additional iterations (Figure 1.11). The convergence history is shown in Figure 1.12.

Figure 1.11: Residuals for the Second-Order Energy Calculation

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Note: You should expect to see the residuals jump whenever you change the solution control parameters.

Figure 1.12: Convergence History of Mass-Weighted Average Temperature

4. Save the case and data les for the second-order solution (elbow2.cas.gz and elbow2.dat.gz). File Write Case & Data... (a) Enter elbow2.gz for Case/Data File. (b) Click OK to save the les and close the Select File dialog box. The les elbow2.cas.gz and elbow2.dat.gz will be saved in your default folder.


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5. Examine the revised temperature distribution (Figure 1.13). Graphics and Animations Contours Set Up...

(a) Make sure that Filled is enabled in the Options group box. (b) Select Temperature... and Static Temperature from the Contours of drop-down lists. (c) Make sure that symmetry is selected from the Surfaces selection list. (d) Click Display (Figure 1.13) and close the Contours dialog box. Figure 1.13 shows the thermal spreading of the warm uid layer near the outer wall of the bend. To see the eects of second-order discretization, compare Figure 1.13 with Figure 1.6.

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Figure 1.13: Temperature Contours for the Second-Order Solution

6. Display and save an XY plot of the temperature prole across the centerline of the outlet for the second-order solution (Figure 1.14). Plots XYPlot Set Up...

(a) Disable Write to File in the Options group box. The button that was labeled Write... will change to Plot.


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(b) Make sure that Temperature... and Static Temperature are selected from the Y Axis Function drop-down lists. (c) Make sure that z=0 outlet is selected from the Surfaces selection list. (d) Click Plot.

Figure 1.14: Outlet Temperature Prole for the Second-Order Solution (e) Enable Write to File in the Options group box. The button that was labeled Plot will change to Write.... (f) Click Write... to open the Select File dialog box. i. Enter outlet temp2.xy for XY File. ii. Click OK to save the temperature data. (g) Close the Solution XY Plot dialog box.

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Step 11: Adapting the MeshThe elbow solution can be improved further by rening the mesh to better resolve the ow details. In the following steps, you will adapt the mesh based on the temperature gradients in the current solution. Once the mesh is rened, you can continue the calculation. 1. Adapt the mesh in the regions of high temperature gradient. Adapt Gradient...

(a) Make sure that Rene is enabled in the Options group box. ANSYS FLUENT will not coarsen beyond the original mesh for a 3D mesh. Hence, it is not necessary to deselect Coarsen in this instance. (b) Select Temperature... and Static Temperature from the Gradients of drop-down lists. (c) Click Compute. ANSYS FLUENT will update the Min and Max values to show the minimum and maximum temperature gradient. (d) Enter 0.004 for Rene Threshold. It is a good rule of thumb to use 10% of the maximum gradient when setting the value for Rene Threshold. (e) Click Mark. ANSYS FLUENT will report in the console that approximately 940 cells were marked for adaption.


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(f) Click Manage... to open the Manage Adaption Registers dialog box.

i. Click Display. ANSYS FLUENT will display the cells marked for adaption in the graphics window (Figure 1.15).

Figure 1.15: Cells Marked for Adaption Extra: You can change the way ANSYS FLUENT displays cells marked for adaption (Figure 1.16) by performing the following steps: A. Click Options... in the Manage Adaption Registers dialog box to open the Adaption Display Options dialog box.

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B. Enable Draw Mesh in the Options group box. The Mesh Display dialog box will open.

C. Ensure that only the Edges option is enabled in the Options group box. D. Select Feature from the Edge Type list. E. Select all of the items except default-interior from the Surfaces selection list. F. Click Display and close the Mesh Display dialog box. G. Enable Filled in the Options group box in the Adaption Display Options dialog box. H. Enable Wireframe in the Rene group box. I. Click OK to close the Adaption Display Options dialog box. J. Click Display in the Manage Adaption Registers dialog box. K. Rotate the view and zoom in to get the display shown in Figure 1.16.


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Figure 1.16: Alternative Display of Cells Marked for Adaption L. After viewing the marked cells, rotate the view back and zoom out again to return to the angle and magnication shown in Figure 1.13. ii. Click Adapt in the Manage Adaption Registers dialog box. A Question dialog box will open, conrming your intention to adapt the mesh. Click Yes to proceed.

Note: There are two dierent ways to adapt. You can click Adapt in the Manage Adaption Registers dialog box as was just done, or close this dialog box and perform the adaption using the Gradient Adaption dialog box. If you use the Adapt button in the Gradient Adaption dialog box, ANSYS FLUENT will recreate an adaption register. Therefore, when the Manage Adaption Registers dialog box is open, use the Adapt button in it to save time. iii. Close the Manage Adaption Registers dialog box. (g) Close the Gradient Adaption dialog box.

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2. Display the adapted mesh (Figure 1.17). General Display...

(a) Make sure that All is selected from the Edge Type list. (b) Deselect all of the highlighted items from the Surfaces selection list except for symmetry. (c) Click Display and close the Mesh Display dialog box.

Figure 1.17: The Adapted Mesh


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3. (optional) Check the case to conrm that the

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