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ANSYS CFX-Mesh Tutorials ANSYS Workbench Release 9.0 November 2004 ANSYS, Inc. is a UL registered ISO 9001: 2000 Company

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  • ANSYS CFX-MeshTutorials

    ANSYS Workbench Release 9.0

    November 2004

    ANSYS, Inc. is aUL registeredISO 9001: 2000Company

  • Table of ContentsIntroduction to the CFX-Mesh Tutorials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

    1. List of Features ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42. Legal Notices ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

    Tutorial 1: Static Mixer ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91. Introduction to CFX-Mesh ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

    Tutorial 2: Static Mixer (Refined Mesh) ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271. Modifying the Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272. Geometry Modification ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303. Updating the Geometry in CFX-Mesh ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

    Tutorial 3: Process Injection Mixing Pipe ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

    Tutorial 4: Circular Vent ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

    Tutorial 5: Blunt Body ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

    Tutorial 6: Butterfly Valve ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

    Tutorial 7: Catalytic Converter .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

    Tutorial 8: Annulus ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 812. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

    Tutorial 9: Mixing Tube ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 871. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 872. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

    Tutorial 10: Heating Coil .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 931. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 932. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

    Tutorial 11: Airlift Reactor ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1031. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1042. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

    Tutorial 12: Room with Air Conditioning ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1131. Geometry Creation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1132. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

    Tutorial 13: Can Combustor ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1211. Geometry Import .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1222. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

    Tutorial 14: CAD Cleanup and Meshing ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1271. Mesh Generation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

    CFX-Mesh Tutorials . . SAS IP, Inc.

  • vi

  • Introduction to the CFX-Mesh TutorialsThe CFX-Mesh Tutorials are a set of tutorial examples which demonstrate how to set up the geometry and meshfor a variety of different problems. The tutorials cover most of the meshing functionality available in CFX-Meshtogether with some of the most commonly-used geometry features from DesignModeler. Each example resultsin the creation of CFX-5 GTM file, which can be imported directly into CFX-Pre. You will find instructions for settingup CFD simulations using these meshes in the CFX-5 Tutorials which are part of the main on-line help for CFX-5.

    A few of these tutorials require the use of Parasolid or DesignModeler files as a starting point for the geometrycreation. Where such a file is required, the introduction to the tutorial explains this. If you have not already obtainedthese files, they should be readily available from the CFX Community Website: go to http://www-waterloo.an-sys.com/cfxcommunity. This site is available to all registered CFX users. If you have not already got a usernameand password, go to http://www-waterloo.ansys.com/cfx/community/apply.htm to apply.

    These tutorial instructions are based on ANSYS Workbench 9.0. Some of the tutorials will not work in earlierversions of ANSYS Workbench since they rely on new features, and other tutorials may be hard to follow. If youstill have ANSYS Workbench 8.1 then you can find tutorial instructions explicitly for this version on the CFXCommunity Website using the following link: http://www-waterloo.ansys.com/cfxcommunity/technotes/docu-mentation/CFX-Mesh_8.1/index.html.

    If you want to print out the tutorials, then we recommend that you follow the link to the CFX Community Websiteto download a package in pdf format, and use this for printing.

    Note that if you create the mesh by following the instructions given in these examples, you may not be able toset up the physics in CFX-5 by using the CFX-Pre session file without getting errors which you need to fix up afterthe session file has finished playing. You can always follow the CFX-5 tutorial instructions manually instead. Thisis because the CFX-Pre session files are set up to use the mesh files provided with CFX-5, and some face and bodyidentifications are different to the ones which you would get by creating meshes by following these instructions.In most cases, you can use the CFX-Pre session file to set up the physics, and then manually apply the locationof the domain and any sub-domains if required. In addition, in the Combustor tutorial, you will also need to setup the Vane Surfaces location manually, and in the Catalytic Converter tutorial, you may need to delete andrecreate the two Domain Interfaces manually.

    Can I Skip the Geometry Creation?

    If you are only interested in the meshing parts of the tutorials and want to skip all of the geometry creation, thenyou should follow the link to the CFX Community Website above to download the DesignModeler .agdb filesfor the tutorials of interest. You can then use these for each tutorial as follows:

    1. Open ANSYS Workbench, and create a new empty project. Save the project with the name suggestedby the tutorial.

    2.At the left side of the Project Page, click on Browse (under Link to Geometry File). Select the ap-propriate .agdb in the file browser which opens up.

    3. In the left-hand column, near the top, click on Generate CFX Mesh. Then continue with the tutorial fromthe beginning of the Mesh Generation section, ignoring the instructions on opening CFX-Mesh.

    CFX-Mesh Tutorials . . SAS IP, Inc.

  • What if I Don't Have DesignModeler?

    If you don't have DesignModeler or don't have a license to run DesignModeler, then you can still work throughthe meshing parts of these tutorials as follows:

    1. Follow the link to the CFX Community Website above to download the Parasolid Geom.x_tfiles for the tutorials of interest.

    2. If you have a license to do direct Parasolid import, then these files can be imported into CFX-Mesh directly,following the instructions below.

    3. If you don't have a license for direct Parasolid import but do have a license to import files from anotherCAD package, then import the Parasolid files into that CAD package, and then use the resulting CAD filesin CFX-Mesh by following the instructions below.

    4. If your CAD package does not support the import of Parasolid files either, please contact your supportrepresentative to obtain a set of geometry files that you can import.

    The instructions for importing the relevant CAD files (Parasolid or otherwise) into CFX-Mesh are as follows:

    1. Open ANSYS Workbench, and create a new empty project. Save the project with the name suggestedby the tutorial.

    2.At the left side of the Project Page, click on Browse (under Link to Geometry File). Select the ap-propriate CAD filename in the file browser which opens up.

    3. In the left-hand column, near the top, click on Generate CFX Mesh. Then continue with the tutorial fromthe beginning of the Mesh Generation section, ignoring the instructions on opening CFX-Mesh.

    If you import the Parasolid files into your CAD package and then import the resulting CAD file into CFX-Meshyou may occasionally find that whilst the geometry still looks the same afterwards, certain features may changesubtly due to differences in the geometry representation in your CAD package.

    Specific tutorials will need minor adaptations as a result of importing Parasolid files (or other CAD files) directly:

    Tutorial 2: Static Mixer (Refined Mesh) - You will not to be able to continue with the tutorial beyond thepoint at which you write the file StaticMixerRefMesh.gtm as this relies on being able to modify thegeometry in DesignModeler. It is recommended that you read through the section called Updating theGeometry in CFX-Mesh if you want to see how to update your geometry in CFX-Mesh, as this is notcovered by any other tutorial.

    Tutorial 6: Butterfly Valve - The units after you import the Parasolid file are always meters, but the tutorialinstructions expect the geometry to be in millimeters. You will need to enter all given values in the correctunits of meters i.e. when the tutorial asks you to set a Default Body Spacing of 4.5 mm, you must enter0.0045 m.

    Tutorial 7: Catalytic Converter - The units after you import the Parasolid file are always meters, but thetutorial instructions expect the geometry to be in centimeters. You will need to enter all given values inthe correct units of meters i.e. when the tutorial asks you to set a Default Body Spacing of 1.0 cm, youmust enter 0.01 m.

    Tutorial 8: Annulus - The units after you import the Parasolid file are always meters, but the tutorial instruc-tions expect the geometry to be in feet. You will need to enter all given values in the correct units ofmeters i.e. when the tutorial asks you to set a Default Body Spacing of 0.02 ft, you must enter 0.006 m.Conversions for the other values are given in the tutorial instructions.

    Introduction to the CFX-Mesh Tutorials

    CFX-Mesh Tutorials . . SAS IP, Inc.2

  • Tutorial 9: Mixing Tube - The units after you import the Parasolid file are always meters, but the tutorialinstructions expect the geometry to be in millimeters. You will need to enter all given values in the correctunits of meters i.e. when the tutorial asks you to set a Default Body Spacing of 0.6 mm, you must enter0.0006 m.

    Tutorial 10: Heating Coil

    The DesignModeler geometry puts both solid bodies into one part and creates shared faces betweenthem, so that CFX-Mesh can create one mesh containing both bodies. The result of the direct Parasolidimport will be to have two bodies each in a separate part, so CFX-Mesh will create one file Heating-CoilMesh.gtm which contains two separate meshes, and hence two separate assemblies in CFX-Pre.This file can be used in CFX-Pre as usual; an example of how to deal with having multiple assembliesin CFX-Pre is detailed in the CFX-5 example Tutorial 10: Flow in a Catalytic Converter (although youmust use Fluid-Solid Interfaces for this example since you are connecting a fluid domain to a soliddomain).

    You are advised that if you wish to work through the CFX-5 example after creating your mesh, youshould use the CFX-Pre Mesh file HeatingCoilMesh.gtm provided by your CFX-5 installation, sincethe tutorial instructions were written expecting one mesh containing both bodies.

    In addition, since you have two separate parts in the CFX-Mesh session, you should NOT enable SurfaceProximity as suggested by the tutorial instructions: if surface proximity is enabled on a multi-partgeometry, then the mesher sees the faces in each part as being very close together but not coincident,and so attempts to refine the mesh in this region far more than is required for this tutorial.

    The tutorial instructions ask you to suppress one of the Bodies contained in Part 3. Instead, you shouldclick on the name of each part in turn, and see which one corresponds to the coil and which one tothe container. Then right-click over the part which corresponds to the coil, and select Suppress. Later,in order to see which 2D Regions you have selected, suppress the other part in the same way. After-wards, unsuppress both parts by right-clicking on their names and selecting Unsuppress.

    Tutorial 11: Airlift Reactor

    The units after you import the Parasolid file are always meters, but the tutorial instructions expect thegeometry to be in centimeters. You will need to enter all given values in the correct units of metersi.e. when the tutorial asks you to set a Default Body Spacing of 1.0 cm, you must enter 0.01 m.

    The DesignModeler geometry puts both solid bodies into one part and creates shared faces betweenthem, so that CFX-Mesh can create one mesh containing both bodies. The result of the direct Parasolidimport will be to have two bodies each in a separate part, so CFX-Mesh will create one file Bubble-ColumnMesh.gtm which contains two separate meshes, and hence two separate assemblies in CFX-Pre. This file can be used in CFX-Pre as usual; an example of how to deal with having multiple assembliesin CFX-Pre is detailed in the CFX-5 example Tutorial 10: Flow in a Catalytic Converter.

    You are advised that if you wish to work through the CFX-5 example after creating your mesh, youshould use the CFX-Pre Mesh file BubbleColumnMesh.gtm provided by your CFX-5 installation, sincethe tutorial instructions were written expecting one mesh containing both bodies.

    When you create the Composite 2D Region DraftTube, you may find that the selection rectanglesappear in the order (from left to right): outside of the column, draft tube face (inside), draft tube face(outside), face from symmetry plane, instead of the order listed in the tutorial instructions. You cantell which order they appear in, since the selection rectangle corresponding to the draft tube (outside)will be the same color as the outside of the column. This is the one which you require.

    Tutorial 13: Can Combustor

    3CFX-Mesh Tutorials . . SAS IP, Inc.

  • The units after you import the Parasolid file are always meters, but the tutorial instructions expect thegeometry to be in centimeters. You will need to enter all given values in the correct units of metersi.e. when the tutorial asks you to set a Default Body Spacing of 1.6 cm, you must enter 0.016 m.

    The DesignModeler geometry puts all five solid bodies into one part and creates shared faces betweenthem, so that CFX-Mesh can create one mesh containing all of the bodies. The result of the directParasolid import will be to have five bodies each in a separate part, so CFX-Mesh will create one fileCombustorMesh.gtm which contains five separate meshes, and hence five separate assemblies inCFX-Pre. This file can be used in CFX-Pre as usual; an example of how to deal with having multiple as-semblies in CFX-Pre is detailed in the CFX-5 example Tutorial 10: Flow in a Catalytic Converter.

    You are advised that if you wish to work through the CFX-5 example after creating your mesh, youshould use the CFX-Pre Mesh file CombustorMesh.gtm provided by your CFX-5 installation, sincethe tutorial instructions were written expecting one mesh containing all of the bodies.

    1. List of Features

    The following table shows you which geometry features are covered in which tutorial.

    1413121110987654321

    Sketching Mode

    Draw Toolbox

    Modify Toolbox

    Dimensions Toolbox

    Constraints Toolbox

    Settings Toolbox

    3D Features

    Extrude

    Revolve

    Sweep

    Skin/Loft

    Other Features

    Parasolid Import

    Multiple Bodies

    Freeze/Unfreeze/Add Frozena

    Body Operationsb

    Plane Creation from Facesc

    Imprint Facesd

    Enclosure

    aFreeze/Unfreeze/Add Frozen: for multiple bodies and for creating bodies which enclose another bodybBody Operations: for copying, moving, and subtracting bodies from other bodiescPlane Creation from Faces: for 3D Feature operations on existing surfacesdImprint Faces: for Boundary Condition Surfaces

    The following table shows you which meshing features are covered in which tutorial.

    Introduction to the CFX-Mesh Tutorials

    CFX-Mesh Tutorials . . SAS IP, Inc.4

  • 1413121110987654321

    2D Region Groups

    Face Spacinga

    Curvature-Sensitive Meshing

    Controlsb

    Periodicity

    Inflationc

    Stretch

    Proximityd

    Preview Groupse

    Extruded 2D Meshing

    Parallel Volume Meshing

    Geometry Update

    CAD Check

    Virtual Faces and Edges

    Short Edge Removal

    aFace Spacing: for refining the mesh on a particular face or facesbControls: for refining the mesh near a point, line or trianglecInflation: for producing prism elements along a boundary in order to resolve the boundary betterdProximity: for refining the mesh when two faces or two edges are close but not joinedePreview Groups: for previewing part or all of the surface mesh

    2. Legal Notices

    Copyright and Trademark Information

    Copyright 2004 SAS IP, Inc. All rights reserved. Unauthorized use, distribution or duplication is prohibited.

    ANSYS, DesignSpace, CFX, DesignModeler, DesignXplorer, ANSYS Workbench environment, AI*Environment,CADOE and any and all ANSYS, Inc. product names referenced on any media, manual or the like, are registeredtrademarks or trademarks of subsidiaries of ANSYS, Inc. located in the United States or other countries. ICEM CFDis a trademark licensed by ANSYS, Inc. All other trademarks and registered trademarks are property of their re-spective owners.

    ANSYS, Inc. is a UL registered ISO 9001: 2000 Company.

    ANSYS Inc. products may contain U.S. Patent No. 6,055,541.

    Microsoft, Windows, Windows 2000 and Windows XP are registered trademarks of Microsoft Corporation.Inventor and Mechanical Desktop are registered trademarks of Autodesk, Inc.SolidWorks is a registered trademark of SolidWorks Corporation.Pro/ENGINEER is a registered trademark of Parametric Technology Corporation.Unigraphics, Solid Edge and Parasolid are registered trademarks of Electronic Data Systems Corporation (EDS).ACIS and ACIS Geometric Modeler are registered trademarks of Spatial Technology, Inc.

    FLEXlm License Manager is a trademark of Macrovision Corporation.

    This product contains the following licensed software:

    5CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Legal Notices

  • PCGLSS: Linear Equations Solver Copyright 1992-1995CA&SI, 2004 S.Wright Street, Urbana, IL 61821.Copyright 1992-1995 Computational Applications and System Integration Inc. All rights Reserved.Ph. 217.244.7875/Fax 217.244.7874CA&SI DOES NOT GUARANTEE THE CORRECTNESS OR USEFULNESS OF THE RESULTS OBTAINED USING PCGLSS.CA&SI IS NOT LIABLE FOR ANY CONCLUSIONS OR ACTIONS BASED ON THE RESULTS. IT IS THE RESPONSIBILITYOF THE USER TO CONFIRM THE ACCURACY AND USEFULNESS OF THE RESULTS.Computational Applications and System Integration Inc. All Rights Reserved

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    Tk and Tcl is copyrighted by the Regents of the University of California, Sun Microsystems, Inc., Scriptics Corpor-ation, and other parties. The authors hereby grant permission to use, copy, modify, distribute, and license thissoftware and its documentation for any purpose, provided that existing copyright notices are retained in allcopies and that this notice is included verbatim in any distributions. No written agreement, license, or royaltyfee is required for any of the authorized uses. Modifications to this software may be copyrighted by their authorsand need not follow the licensing terms described here, provided that the new terms are clearly indicated onthe first page of each file where they apply. IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TOANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THEUSE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVEBEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIMANY WARRANTIES,INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,FITNESSFOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN AS IS BASIS,AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,ENHANCEMENTS, OR MODIFICATIONS

    TIFF: Copyright (c) 1988-1997 Sam Leffler, Copyright (c) 1991-1997 Silicon Graphics, Inc. - Permission to use, copy,modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee,provided that (i) the above copyright notices and this permission notice appear in all copies of the software andrelated documentation, and (ii) the names of Sam Leffler and Silicon Graphics may not be used in any advertisingor publicity relating to the software without the specific, prior written permission of Sam Leffler and SiliconGraphics.

    libpng version 1.0.8 - July 24, 2000 Copyright (c) 1998-2000 Glenn Randers-Pehrson Copyright (c) 1996, 1997 Andreas Dilger Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.

    This software is based in part on the work of the Independent JPEG Group.

    PVM version 3.4: Parallel Virtual Machine System, University of Tennessee, Knoxville TN., Oak Ridge NationalLaboratory, Oak Ridge TN., Emory University, Atlanta GA., Authors: J. J. Dongarra, G. E. Fagg, G. A. Geist, J. A. Kohl,R. J. Manchek, P. Mucci, P. M. Papadopoulos, S. L. Scott, and V. S. Sunderam, C) 1997 All Rights Reserved - NOTICE- Permission to use, copy, modify, and distribute this software and its documentation for any purpose and withoutfee is hereby granted provided that the above copyright notice appear in all copies and that both the copyrightnotice and this permission notice appear in supporting documentation.

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    ACIS Geometric Modeler and ACIS InterOp from Spatial Technology, Inc.

    Introduction to the CFX-Mesh Tutorials

    CFX-Mesh Tutorials . . SAS IP, Inc.6

  • Parasolid and Parasolid IGES from EDS.Parasolid Bodyshop from Unigraphics Solutions2D DCM from D-Cubed Ltd.GHS3D meshing technology by P. L. George, INRIA, France.Visual MainWinCopyright 2002 Mainsoft Corporation. All rights reserved. Mainsoft, Mainwin, the software porting company,e-porting, the e-porting company, and Visual MainWin are trademarks or registered trademarks of MainsoftCorporation in the United States and/or foreign countries.ZLIB 1.1.3 Copyright (C) 1995-1998 Jean-loup Gailly and Mark AdlerMeschach Library Copyright (C) 1993 David E. Steward & Zbigniew Leyk, all rights reserved.DesignSpace contains Simulation Wizard, Patent Pending.

    Disclaimer Notice

    Information in this Information System is subject to change without notice. Complying with all applicablecopyright and exporting laws is the responsibility of the user. No part of this system may be reproduced ortransmitted in any form or by any means, electronic or mechanical, without prior written permission of ANSYS,Inc.

    This document has been reviewed and approved in accordance with ANSYS, Inc. Documentation Review andApproval Procedures.

    This ANSYS, Inc. software product and program documentation are furnished by ANSYS, Inc. under an ANSYSsoftware license agreement that contains provisions concerning non-disclosure, copying, length and nature ofuse, warranties, disclaimers and remedies, and other provisions. The Program and Documentation may be usedor copied only in accordance with the terms of that license agreement.

    THIS SOFTWARE CONTAINS CONFIDENTIAL INFORMATION AND TRADE SECRETS OF SAS IP, INC. USE, DISCLOSURE,OR REPRODUCTION IS PROHIBITED WITHOUT THE PRIOR EXPRESS WRITTEN PERMISSION OF SAS IP, INC.

    Warning: This computer program is protected by copyright law and international treaties. Unauthorized repro-duction or distribution of this program, or any portion of it, may result in severe civil and criminal penalties, andwill be prosecuted to the maximum extent possible under the law.

    The above legal notices for Third Party Software are required to be reproduced by the third party licensors.

    U.S. GOVERNMENT RIGHTS

    Use, duplication, or disclosure by the U.S. Government is subject to restrictions set forth in the ANSYS, Inc. licenseagreement and as provided in DFARS 227.7202-1(a) and 227.7202-3(a) (1995), DFARS 252.227-7013(c)(1)(ii) (OCT1988), FAR 12.212(a) (1995), FAR 52.227-19, or FAR 52.227-14 (ALT III), as applicable.

    7CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Legal Notices

  • 8

  • Tutorial 1: Static Mixer

    This example shows geometry creation and meshing for a simple static mixer. It assumes that you have neverused ANSYS Workbench before and gives detailed instructions on every step needed to construct the example.The following geometry and meshing features are illustrated:

    basic geometry creation including Revolve and Extrude operations; and

    basic meshing operations.

    If you want to skip the geometry creation part of the tutorial, then see the instructions in Introduction to theCFX-Mesh Tutorials. However, even if you are not going to work through the geometry creation section, it maybe worth reading through it if you have not used ANSYS Workbench before, since it contains some backgroundinformation which is also applicable to CFX-Mesh.

    1. Introduction to CFX-Mesh

    In order to create a mesh using CFX-Mesh, the steps are as follows.

    1. Create the Geometry.

    2. Define Regions.

    3. Define the Mesh Attributes.

    4. Create the Surface Mesh (this is optional).

    5. Create the Volume Mesh.

    You can create the geometry either in ANSYS Workbench or by importing it from a CAD package. The geometrycreation tool in ANSYS Workbench is DesignModeler, a parametric feature-based solid modeler. Most of the CFX-Mesh Tutorial Examples include instructions on creating geometry in DesignModeler, although for full document-ation you should consult the DesignModeler Help.

    CFX-Mesh Tutorials . . SAS IP, Inc.

  • The remaining four steps are all carried out within CFX-Mesh. The creation of the surface mesh is optional; if itis not created explicitly, then it will be generated as part of the creation of the volume mesh.

    ANSYS Workbench helps you to manage all of the files created by DesignModeler and CFX-Mesh by the use ofthe Project Page. Your first step after opening ANSYS Workbench will be to create a new project, and by returningto the Project Page (which is available at any point during your ANSYS Workbench session) you can switchbetween DesignModeler and CFX-Mesh, add new files to the project, and so on. We recommend that you createeach new project in a new directory so that all the files for each project are kept separate. You can also then runthe CFX-5 software from the same directory after generating the mesh.

    2. Geometry Creation

    Creating the Project

    The first step for any new case is to create the project.

    1. Open ANSYS Workbench. On Windows, this can be done by going to the Start Menu>Programs sectionand selecting ANSYS 9.0>ANSYS Workbench. On UNIX, this can be done by running /an-sys_inc/v90/aisol/startpage if your installation used the default settings. Otherwise, you should runinstall_dir/ansys_inc/v90/aisol/startpage.

    2. Start a new project from scratch by selecting Empty Project from the New section of the Start windowin the middle of the ANSYS Workbench window. (Depending on which modules are available, you mayfind that you need to scroll down to see Empty Project icon.) The Project Page will appear, containingUnsaved Project.

    3. The next setting is to tell ANSYS Workbench where you want your project files to be created. SelectFile>Save, and save the project as StaticMixer.wbdb in a new directory of your choice. This directorywill be the default location for all of the project files which you will create during the tutorial.

    You can then open DesignModeler in order to start creating the geometry.

    1.At the left side of the Project Page, click on New geometry (under Create DesignModeler Geo-metry).

    2. In the popup window, select Meter as the desired length unit.

    Overview of DesignModeler

    Once DesignModeler opens up, you will be able to see four main areas to the window.

    Tutorial 1: Static Mixer

    CFX-Mesh Tutorials . . SAS IP, Inc.10

  • The Model View displays the geometry. The geometry can be manipulated using the mouse buttons. Forexample, holding down the middle mouse button and moving the mouse over the Model View will rotatethe geometry. Clicking the right mouse button over the Model View will bring up a menu which includesvarious options for manipulating the model as well as other options which are particular to what geometryoperation you are performing or what objects are selected. To put the model into a particular view, youcan also use the Triad which is displayed at the bottom right corner of the Model View: click on one of theaxes or on the cyan-colored ball to move the model. You can zoom out to view the entire model by right-clicking over the Model View and selecting Zoom to Fit. You can zoom in to a selected area by clickingwith the right mouse button and dragging the mouse over the required area whilst holding down thebutton.

    The Details View shows the details for the selected object. No object is selected when DesignModeler isfirst opened, so it is blank in the picture above. It can be used to edit the details (including the name ofthe object) by simply typing over the information to be updated.

    The Tree View shows all of the features of the geometry, and their states. When DesignModeler is firstopened, only the three default planes (XYPlane, ZXPlane, and YZPlane) are present, together with anentry which shows you that there are currently 0 Parts, 0 Bodies. As you perform geometry creation op-erations, the structure of the tree will expand to show these. The geometry operations such as Extrudeand Revolve are applied from the top of the tree downwards. For example, in the tree shown below, Ex-trude2 was the first operation, followed by Revolve2.

    11CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Geometry Creation

  • The symbols next to the operations and features indicate their status:

    MeaningSymbol

    Everything is OK.

    The item is suppressed i.e. not taking any effect (it can be unsuppressed later).

    Something is wrong with the item e.g. you tried to generate it before you had fully specified it, or youmodified one of the features above it which makes the specifications of the item invalid. (You can seethe error messages by right-clicking on the object and selecting Show Errors and Warnings.)

    The item needs to be generated or re-generated (because changes to the settings have been made sinceit was last generated).

    The sketch will remain visible even when not selected.

    The Body has been hidden (made invisible).

    The top part of the window contains the various menus and toolbars.

    DesignModeler has two main modes of operation, and you will have to switch between them as you build upyour model. In Modeling Mode, the Tree View is shown, as in the picture above. However, DesignModeler usessketches (collections of edges in a plane) to build up solid models, and to create these sketches, you need to bein Sketching Mode. To switch between the two modes, the tabs (Sketching and Modeling) at the bottom of theTree View are used: simply click on the appropriate tab to switch between the two modes.

    The area which is occupied by the Tree View when you are in Modeling Mode is taken up with the sketchingtoolboxes (Draw, Modify, Constraints, Dimensions and Settings) when in Sketching Mode. To switch betweenthem, simply click on their names.

    Recovering from Mistakes

    You are certain to make mistakes as you build up your geometry, so it is important to know how to recover fromthese.

    Tutorial 1: Static Mixer

    CFX-Mesh Tutorials . . SAS IP, Inc.12

  • If you are in Sketching Mode, then the Undo button in the Undo/Redo Toolbar towards the top of the windowcan be used to undo sketching operations. The Back button (accessed by right-clicking over the Model View)can be used to undo the selection of (for example) the last point in a polyline, whilst sketching.

    If you are in Modeling Mode, and you have not yet generated your feature (such as Extrude) you can either justmake further changes in the Details View, or you can delete it by right-clicking on its name in the Tree View andselecting Delete.

    After generating a feature, you can delete it by selecting it in the Tree View and using the Delete on the rightmouse menu. If you have generated a feature e.g. Extrude and then realize (for example) that you selected thewrong sketch to define it, you will need to use the Edit Selections feature. This is accessed by selecting right-clicking over the name of the feature in the Tree View and selecting Edit Selections: you will then be able toedit the selections by using the Details View as usual.

    Creating the Solid

    You need to start creating the Static Mixer geometry by creating a sketch to make the main body of the mixer.

    1. Click on ZXPlane in the Tree View towards the top left of the screen.

    2. Click on the Sketching tab (underneath the Tree View) to work on the sketch.

    Each sketch is created in a plane. By selecting the ZXPlane immediately before going into sketching mode, youensure that the sketch you are about to create is based on the ZXPlane.

    Before starting to create your sketch, it helps to set up a grid of lines on the plane in which the sketch will bedrawn. The presence of the grid allows the precise positioning of points (when Snap is enabled).

    1. Click on Settings (in the Sketching tab) to open the Settings Toolbox.

    2. Click on Grid and turn ON Show in 2D and Snap.

    3. Click on Major Grid Spacing and set it to 1.

    4. Click on Minor-Steps per Major and set it to 2.

    5. You now need to zoom in to see the effect of changing the Minor-Steps per Major. Click the right mousebutton to the top left of the plane center in the Model View and drag a box across it to zoom into themiddle of the grid. When you release the mouse button the model will be magnified to show the selectedarea.

    13CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Geometry Creation

  • You now have a grid of squares with the smallest squares being 50 cm across. Because Snap is enabled, you willonly be able to select points that are on this grid to build your geometry, and this can often help to positionobjects correctly.

    1. Select the Draw Toolbox from the Sketching tab.

    2. Click on Polyline and then create the shape shown below:

    a. Click on the grid in the position where one of the points from the shape needs to be placed (itdoesn't matter which point).

    b. Then click on each successive point to make the shape.

    c. If at any point you click on the wrong place, just click with the right mouse button over the ModelView and select Back from the right mouse button menu to undo the point selection.

    d. To close the polyline after selecting the last point, click with the right mouse button to bring up amenu and choose Closed End.

    Note that the longest straight line (4 m long) in the diagram below is along the z-axis (located at x = 0m).

    You will now create the main body of the mixer by revolving the new sketch around the Z-axis.

    1.Select Revolve from the 3D Features Toolbar. This toolbar is located above the Model View.

    2. Details of the Revolve operation are shown in the Details View at the bottom left of the window. Leavethe name of the Revolve as the default, Revolve1.

    3. The Base Object is the name of the sketch to be revolved. It defaults to the sketch which you have justcreated, Sketch1, so this setting does not need to be changed.

    4. The Axis for the rotation does not have a default setting. In the Model View, click on the grid line whichruns along the Z-axis and then click on Apply in the Details View. You should find that the text next toAxis now changes to Selected. If instead it changes to Not Selected with a yellow background, click onthe text Not Selected and then try selecting the axis again in the Model View, remembering to pressApply in the Details View after you have selected it.

    Tutorial 1: Static Mixer

    CFX-Mesh Tutorials . . SAS IP, Inc.14

  • 5. Leave Operation set to Add Material since you need to create a solid. (The other options allow you tomodify existing solids and to deal with multiple solids.)

    6. The sketch needs to be revolved by a full 360 degrees, so change Angle from 30 degrees to 360 degrees.Leave the other settings as default.

    7.To activate the revolve operation, you need to click on Generate. This can be selected from themenu which appears when you click with the right mouse button almost anywhere in the window, orfrom the 3D Features Toolbar towards the top of the window.

    After generation, you should find you have a solid as shown below.

    Now you need to create the two side pipes. This involves creating and extruding two new sketches. To make iteasier to see the grid when creating the sketches, the first step is to make the solid invisible for now.

    1. In the Tree View, click on the plus sign next to 1 Part, 1 Body to open up the tree structure.

    2. Position your cursor over the text Solid and then click with the right mouse button and select Hide Body.

    3. Select ZXPlane in the Tree View again, and create a new sketch based on this plane by using the New

    Sketch ( ) button on the Active Plane/Sketch Toolbar, which is located above the Model View.

    4. Select the Sketching tab.

    5. Create a circle as shown in the picture below:

    a. Select the Draw Toolbox.

    b. Select Circle, click on the grid at the center of the circle and then drag the mouse to define the ra-dius.

    15CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Geometry Creation

  • Now you need to extrude this sketch to make the first side-pipe.

    1.Select Extrude from the 3D Features Toolbar. This toolbar is located above the Model View.

    2. In the Details View at the bottom left of the window, change Direction to Reversed, in order to extrudein the opposite direction to the plane normal.

    3. Change the Depth to 3 m. The rest of the settings can be left as their default. The Add Material settingwill mean that material is added to the existing solid, rather than a new solid being created.

    4.To activate the extrude operation, you need to click on Generate as before.

    In order to see the result of this, you will have to make the solid visible again:

    1. In the Tree View, position your cursor over the text Solid and then click with the right mouse button andselect Show Body.

    2. Click the middle mouse button over the middle part of the Model View and drag the mouse about withthe button held down to rotate the model. Check that the Solid looks like the picture below when rotatedinto a viewing position so that the side-pipe is clearly visible.

    Tutorial 1: Static Mixer

    CFX-Mesh Tutorials . . SAS IP, Inc.16

  • 3. In the Tree View, position your cursor over the text Solid and then click with the right mouse button andselect Hide Body.

    To create the other side pipe, the same operations are used.

    1. Select ZXPlane in the Tree View again, and create a new sketch based on this plane by using the New

    Sketch ( ) button on the Active Plane/Sketch Toolbar, which is located above the Model View.

    2. Select the Sketching tab.

    3. Right-click over the Model View and select View>Isometric View to put the sketch back into a sensibleviewing position. Then right-click again and select Zoom to Fit to zoom into the sketch, if it appears toosmall.

    4. From the Draw Toolbox, select Circle and then create the second circle shown in the picture below:

    1.Select Extrude from the 3D Features Toolbar.

    2. In the Details View, set Direction to Normal, in order to extrude in the same direction as the plane normal.

    17CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 2: Geometry Creation

  • 3. Change the Depth to 3 m.

    4.To activate the extrude operation, you need to click on Generate as before.

    5. In the Tree View, position your cursor over the text Solid and then click with the right mouse button andselect Show Body.

    The geometry is now complete.

    1. Select File>Save and accept the default filename.

    Before moving on, practise using the mouse to manipulate the model in the Model View. This is essential to beable to move the model into positions which are good for selecting or looking closely at particular parts of themodel.

    1.Ensure that Rotate mode is selected from the Rotation Modes Toolbar at the top of the window.This is the default mode.

    2. Click the middle mouse button over the middle part of the Model View and drag the mouse about withthe button held down to rotate the model. You have already met this way of moving the model around(free rotation) earlier in the tutorial. It is the most common way to move the model.

    3. Now move the mouse button towards the top left of the Model View. As you get near to the top left, the

    cursor should change from to . If you now click the middle mouse button (with the newcursor showing) and drag the mouse about with the button held down, you will be able to rotate themodel about an axis which points out of the screen (roll). This can be useful if you are trying to get themodel into a particular position.

    4. There are two more types of rotation. Move the cursor back towards the left of the screen. Very close to

    the left edge of the Model View, you will find that the cursor changes to . If you click the middlemouse button with this cursor showing, then the rotation is constrained to be around a vertical axis inthe plane of the screen. If you move the cursor to the top of the Model View, you get the other cursor

    . If you click the middle mouse button with this cursor showing, then the rotation is constrainedto be around a horizontal axis in the plane of the screen.

    Which type of rotation mode you get always depends on the position of the cursor. The picture belowshows the areas of the Model View which correspond to each type of rotation. Note that the circular regionwhere you get free rotation will always fill the smallest dimension of the window.

    Tutorial 1: Static Mixer

    CFX-Mesh Tutorials . . SAS IP, Inc.18

  • 5. Put the model back into the Isometric View by clicking on the cyan-colored ball in the Triad at the bottomright of the Model View.

    Now suppose that you wanted to zoom in on one of the pipe ends.

    1. Right-click on the Model View to the top left of the pipe end which is visible and drag a box across it.When you release the mouse button, the model will expand so that the contents of the box are visibleacross the whole Model View.

    2. Try rotating the model. You will find that the model by default rotates around the model center, so thepipe end quickly moves out of view. You can change this as follows. Bring the pipe end back into view,and click once with the left mouse button on the pipe end. DesignModeler will place a small red spherewhere you clicked, and then move the model so the small red sphere moves to the middle of the ModelView. If you now try rotation, you will find that the model rotates around the small red sphere, not themodel center, so the pipe end is always in view. (To change back to rotating around the model center,click once with the left mouse button anywhere in the Model View that is away from the model itself.)

    3. Zoom out again by holding down the Shift key on the keyboard, pressing the middle mouse button anddragging the mouse downwards. You can zoom in by dragging the mouse upwards instead. An altern-

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    Section 2: Geometry Creation

  • ative way of enabling the Zoom functionality is to select Zoom mode from the Rotation ModesToolbar. Once this is enabled, zooming in and out is done by clicking and dragging with the left mousebutton. If Zoom mode is selected, then most of the ways that you just tried rotating the model are no

    longer available; you must select Rotate mode again to use them.

    There are two more useful ways to manipulate the model in the Model View.

    1. Pan (or Translate) the model by holding down the Ctrl key on the keyboard, pressing the middle mousebutton and dragging the mouse around. An alternative way of enabling the Pan functionality is to select

    Pan mode from the Rotation Modes Toolbar. Once this is enabled, panning is done by clicking and

    dragging with the left mouse button. Again, you must reselect Rotate mode to use most of thedifferent rotation methods.

    2. Finally, center the model in the Model View and resize it so that it is all visible by selecting Zoom to Fit

    from the Rotation Modes Toolbar.

    In the rest of this tutorial and all of the subsequent tutorials, you should use the functionality described aboveto manipulate the model in any way which is convenient.

    3. Mesh Generation

    In order to set up the mesh, you must first move out of DesignModeler and into CFX-Mesh.

    1. At the top of the ANSYS Workbench window, you should be able to see two tabs: StaticMixer [Project]and StaticMixer [DesignModeler]. Click on StaticMixer [Project] to return to the Project Page.

    2. In the left-hand column, near the top, you should now see an entry Generate CFX Mesh. Click on this.

    3. CFX-Mesh will open up. At first glance it looks very similar to DesignModeler.

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    CFX-Mesh Tutorials . . SAS IP, Inc.20

  • Overview of CFX-Mesh

    CFX-Mesh is designed to have the same look and feel as DesignModeler. In particular, this means that you canuse the same mouse controls to manipulate the model.

    One important difference between DesignModeler and CFX-Mesh is connected to the order of the items in theTree View. In DesignModeler the Tree View shows items in the order that they were created, and the order affectsthe final geometry. In CFX-Mesh the order of the items in the Tree View are not important and all items of thesame type are grouped together, independent of when they were created.

    You will be able to see that various items are already present in the Tree View in DesignModeler; these are thedefault items and contain default settings. Some of the symbols next to items in the Tree View have slightly dif-ferent implications in CFX-Mesh than they did in DesignModeler. In CFX-Mesh, the meanings are as follows:

    MeaningSymbol

    Everything is valid.

    Everything is valid but the item has been automatically changed and you may wish to double-check the settings.This may occur, for example, if you have performed a geometry update which has resulted in a face no longerexisting: if that face appeared in the location list for any mesh feature, then it will have been removed automat-ically as part of the update and so the mesh feature will be marked with this status symbol.

    This means that there is something invalid about the definition of the item or one of its sub-items (which willalso be marked with the same symbol). Often this will be because no required selection has been made.

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    Section 3: Mesh Generation

  • MeaningSymbol

    The item is suppressed (inactive).

    The item is suppressed and will be invalid when it is unsuppressed.

    These status symbols only apply to Preview Groups.

    If the symbol underneath the yellow flash is a green tick, then the Preview Group is valid but either the meshhas not been generated or the generated mesh is out-of-date i.e. it does not reflect the current mesh settings.To generate an up-to-date mesh for the Preview Group, right-click over its name and choose Generate ThisSurface Mesh. To generate an up-to-date mesh on all Preview Groups, right-click over Preview in the Tree Viewand choose to Generate All Surface Meshes.

    If the symbol shows the yellow lightning bolt but the symbol underneath it is a yellow tick, then the PreviewGroup is both out-of-date (see above) and automatically changed. Refer to the table entry for a yellow ticksymbol for details of what might cause an automatic change to a Preview Group.

    If the symbol shows the yellow lightning bolt but the symbol underneath it is a red exclamation mark, then thePreview Group is both out-of-date (see above) and invalid. You must make the Preview Group valid (by makinga valid selection for its Location) before you can generate or regenerate it.

    This indicates that an item contains associated sub-items . Left-click on the symbol to expand the item anddisplay its contents.

    Left-click on the symbol to close the item so that its contents are not visible in the tree.

    The generation of the surface and volume mesh is controlled by the various features that you can access in CFX-Mesh. The type of controls available depend on the mesher used. By default, you are using the Delaunay SurfaceMesher for surface meshing and Advancing Front Volume Mesher for volume meshing.

    In this first example, you will only set up the most basic features for controlling the mesh generation. Only thebasic length scale of the mesh will be specified.

    Setting up the Regions

    The first step is to define some regions on the geometry. Composite 2D Regions are created from the solid faces(primitive 2D Regions) of the geometry. They can be used in CFX-Pre to assign boundary conditions, such as inletsand outlets, to the problem. You do not need to create Composite 2D Regions at all in CFX-Mesh, but it is easierto name and group faces into Composite 2D Regions in CFX-Mesh than it is to select the corresponding meshin CFX-Pre. This example uses an inlet boundary condition at the entrance to each of the two side pipes, anoutlet boundary condition on the end of the funnel outlet and a wall boundary condition for the remainingsurfaces.

    Note There is an important distinction between primitive 2D Regions and the underlying solid faces,which applies when the model has more than one solid. This is explained in the Mesh Generation sectionof the Heating Coil tutorial.

    If you look at the Tree View, you can see that under Regions, one Composite 2D Region is defined already, calledDefault 2D Region. This region will always contain all of the faces of the model which you have not explicitlyassigned to another Composite 2D Region.

    Create the Composite 2D Region for the first inlet:

    1. Right-click over Regions in the Tree View.

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  • 2. Select Insert>Composite 2D Region.

    3. A new object, Composite 2D Region 1, is inserted under Regions in the Tree View. In the Details View,there will be two buttons, Apply and Cancel, next to Location, and this means that you are ready toselect the face from the Model View.

    4. In the Model View, click on the circular face at the end of the side pipe which is at the position with thelowest value of the Y-coordinate. This will turn green to show that it has been selected, as in the picturebelow. You can rotate the model to make it easier to select the appropriate face by holding down themiddle mouse button and moving the mouse over the geometry.

    5. Click on Apply in the Details View.

    6. Change the name of the region to in1: right-click over the name, select Rename and then type over theexisting name.

    Now create the second inlet:

    1. Right-click over Regions in the Tree View.

    2. Select Insert>Composite 2D Region.

    3. A new object, Composite 2D Region 1, is inserted under Regions in the Tree View. In the Model View,click on the circular face at the end of the side pipe which is at the position with the highest value of theY-coordinate.

    4. Click on Apply in the Details View.

    5. Change the name of the region to in2 by right-clicking over the existing name.

    Finally, create the region for the outlet:

    1. Right-click over Regions in the Tree View and select Insert>Composite 2D Region.

    2. Select the circular face at the bottom of the mixer vessel, with the lowest value of the Z-coordinate.

    3. Click on Apply in the Details View.

    4. Change the region name to out.

    It is not necessary to create a fourth Composite 2D Region for the walls of the static mixer. This is because anyremaining faces which are not explicitly assigned to a Composite 2D Region are automatically assigned to the2D Region named Default 2D Region. You can use this region in CFX-Pre to define the location of your wallboundary condition.

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    Section 3: Mesh Generation

  • Setting up the Mesh

    You will only set a single size for all of the elements, in this tutorial. The next tutorial will then improve upon thiscoarse mesh.

    1. Click on Default Body Spacing in the Tree View, which is contained in Mesh>Spacing.

    2. In the Details View, change Maximum Spacing to 0.3 m. This is a coarse length scale for this model, butis reasonable for a first run to generate an approximate solution and to test that the model is workingcorrectly.

    3. Press Enter on the keyboard to set this value.

    The remaining settings will be left as their default.

    Generating the Surface Mesh

    You will now have a look at the surface mesh to see the effect of the chosen length scale.

    1. Click on the plus sign next to Preview in the Tree View to open it up.

    2. Right-click over Default Preview Group and select Generate This Surface Mesh. The Default PreviewGroup always contains all faces in the geometry, so the mesh will be generated everywhere.

    During the generation of the surface mesh, the progress will be displayed using the slider bar which appears tothe bottom left of the CFX-Mesh window.

    1. You can modify the way that the mesh is displayed by clicking on Preview in the Tree View and changingthe options shown in the Details View. For example, by changing the Display Mode you can switch todisplay the mesh in Wire Mesh rather than with solid faces. Simply click on the name Default PreviewGroup to redisplay the surface mesh using the new settings.

    It is not necessary to create the surface mesh within CFX-Mesh, since if it has not been created explicitly it willbe automatically generated when you create the volume mesh. However, in many of these tutorials, you willcreate the surface mesh first, to demonstrate the effect of various mesh settings. It is generally a good idea tocheck the surface mesh before creating the volume mesh, to ensure that any settings you have made have thedesired effect.

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  • Generating the Volume Mesh

    The volume mesh and all of the region information required for CFX-Pre is stored in a CFX-Pre Mesh file *.gtm.The CFX-Pre Mesh File is read into CFX-Pre at the start of the simulation definition.

    Generate the volume mesh as follows.

    1. Right-click on Mesh in the Tree View and select Generate Volume Mesh.

    2. Choose to save the CFX-Pre Mesh File as StaticMixerMesh.gtm.

    During the generation of the volume mesh, the progress will be displayed using the slider bar which appears tothe bottom left of the CFX-Mesh window. When the volume mesh is complete, the slider bar will disappear andyou will be able to take control of the user interface again.

    The mesh is now complete.

    1. Select File>Save to save the CFX-Mesh database as StaticMixer.cmdb in the same directory as theother project files.

    2. At the top of the ANSYS Workbench window, you should be able to see three tabs: StaticMixer [Project],StaticMixer [DesignModeler] and StaticMixer [CFX-Mesh]. Click on StaticMixer [Project] to returnto the Project Page.

    3. Select File>Save to save the project.

    If you want to continue by working through the CFX-5 example Tutorial 1: Flow in a Static Mixer using thenewly-generated mesh, and have CFX-5.7.1 in ANSYS Workbench installed on your machine, then follow thesesteps:

    1. On the Project Page, a new entry will have appeared when you generated the file: Advanced CFD. Underthis entry, double-click on StaticMixerMesh.gtm to open up CFX-Pre.

    2. Once CFX-Pre has opened, choose File>Save Simulation As... to save the simulation as StaticMixer.

    3. Select Tools>Quick Setup Mode... to enter the Quick Setup Mode that this tutorial uses.

    4. Work through the CFX-5.7.1 tutorial, missing out the instructions in the section Creating a New Simula-tion. Note that you do not need to copy the sample file StaticMixerMesh.gtm to your working directoryif you have just created the mesh in CFX-Mesh, since you will want to use your new mesh and not theone supplied with CFX-5. For the Importing a Mesh section, the only action that you need to carry outis to select Assembly from the Select Mesh drop-down list, as the mesh is loaded automatically whenyou start CFX-Pre in the manner described above.

    If you do not have CFX-5.7.1 in ANSYS Workbench installed or do not want to work through the CFX-5 example,then:

    1. Exit from ANSYS Workbench by selecting File>Exit.

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    Section 3: Mesh Generation

  • 26

  • Tutorial 2: Static Mixer (Refined Mesh)

    This example modifies the mesh and geometry for the static mixer example created in the previous example,and assumes that you have access to the files created as part of that example. The following geometry andmeshing features are illustrated:

    modifying an existing mesh setup;

    Inflation, and

    geometry update.

    1. Modifying the Mesh Generation

    Opening the Existing Project

    1. Open ANSYS Workbench.

    2. In the main part of the window, click on the existing StaticMixer project. If it does not appear in the listof recent projects (perhaps because you moved the files), then use Browse to locate the project fileStaticMixer.wbdb instead.

    3.To open CFX-Mesh, double-click on StaticMixer.

    CFX-Mesh will now be opened with the geometry and mesh settings from the previous tutorial.

    Modifying the Mesh Settings

    The first step is to create a refined mesh size over the whole geometry.

    1. Click on Default Body Spacing in the Tree View, which is contained in Mesh>Spacing.

    2. In the Details View, change Maximum Spacing to 0.2 m. This is a smaller length scale for the model thanset previously (0.3 m).

    CFX-Mesh Tutorials . . SAS IP, Inc.

  • 3. Press Enter on the keyboard to set this value.

    The next step is to create an Inflated Boundary on the walls of the mixer. Creating inflated boundaries generatesprismatic elements from the surface by inflating triangular elements into the solid. As a result, near the wallboundaries there will be layers of flat prismatic (wedge-shaped) elements which provide a smaller mesh lengthscale in the direction perpendicular to the wall. This provides better resolution of the velocity field near the wall,where it changes rapidly.

    Inflation can greatly improve accuracy, particularly in a model with a high aspect ratio, such as a long narrowpipe, or in a model where turbulence is significant. Inflation should always be used when you are interested inlift, drag or pressure drop in the model.

    Away from the wall boundaries, the mesh elements will be tetrahedral as they were in Tutorial 1.

    First, you will set the parameters used to control the inflation process, and then you will create the InflatedBoundary itself.

    1. Click on Inflation in the Tree View.

    2. In the Details View, set Number of Inflated Layers to 5. This will give five layers of prism elements.

    3. Set Expansion Factor to 1.3. This controls how fast the thickness of the prism elements grows in suc-cessive layers away from the wall.

    4. Leave the other settings as their default values.

    5. In the Tree View, right-click on Inflation and select Insert>Inflated Boundary.

    6. Click on Default 2D Region in the Tree View to select the faces which are in the Default 2D Region forthe Inflated Boundary. Click on Apply in the Details View. The text should change to read 1 Composite.

    7. Set Maximum Thickness to 0.2 m.

    This creates an Inflated Boundary that uses all the faces in the Default 2D Region. If you later change the 2D Regionsettings so that the Default 2D Region contains different faces, the Inflated Boundary will automatically updateto always use the faces in the Default 2D Region at the time when the mesh is generated.

    Generating the Surface Mesh

    You will now have a look at the surface mesh to see the effect of the chosen length scale and the inflation,compared to the mesh you generated for the previous example. You can use the existing Preview Group to displaythe surface mesh.

    1. Right-click over Default Preview Group and select Generate This Surface Mesh.

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  • You should be able to see that this mesh is finer (has more surface elements) that the mesh you generated inthe first example. Also, note that there are triangular prism elements near the walls of the mixer vessel, the edgesof which can be seen when you look at mesh on the two inlets or outlet.

    Generating the Volume Mesh

    Finally, you can generate the volume mesh.

    1. Right-click on Mesh in the Tree View and select Generate Volume Mesh.

    2. Save the GTM File as StaticMixerRefMesh.gtm.

    The mesh is now complete.

    1. Select File>Save to save the CFX-Mesh database.

    From this point, you could go straight into the CFX-5 example Tutorial 2: Flow in a Static Mixer (Refined Mesh)using the newly-generated mesh. However, this tutorial continues by modifying the geometry in order to illustratehow to set dimensions on geometry objects and how to tell CFX-Mesh to use the updated geometry. Settingdimensions is essential when creating geometry features which have dimensions which are not simple fractionsof the model units, and so cannot use the grid for positioning the points and lines in the sketches.

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    Section 1: Modifying the Mesh Generation

  • 2. Geometry Modification

    In this section, you will change the radius of the inlet pipes to 0.4 m from the initial 0.5 m, without using the gridto position the circle. You will then extend the outlet pipes.

    1. At the top of the ANSYS Workbench window, you should be able to see two tabs: StaticMixer [Project]and StaticMixer [CFX-Mesh]. Click on StaticMixer [Project] to return to the Project Page.

    2.To open DesignModeler, double-click on StaticMixer.

    3. Once DesignModeler has opened, click on the plus sign next to ZXPlane and then select Sketch2 in theTree View, noting which circle it contains. Choose the Sketching tab.

    4. Click on Dimensions (in the Sketching tab) to open the Dimensions Toolbox.

    5. Click on Radius and then select the circle which forms Sketch2 from the Model View.

    6. Click somewhere in the Model View to choose where the label for this dimension will be placed (thisdoes not affect the model in any way, it is purely for display purposes).

    7. If you now look in the Details View at the bottom left of the screen, you will find a section headed Dimen-sions, which contains the radius R1, set to 0.5 m. For now, change the radius to be 0.4 m .

    8.Click on Generate to activate the change.

    You will see that both of the side pipes now have a reduced radius as required. The radius of both the pipeschanged simultaneously as the property of AutoConstraints is turned on by default. This automatically detectsdimensions which are equal and constrains them to be equal so that when one changes, the other does also.See the DesignModeler documentation for more details.

    You have now explicitly defined the dimension (radius) of the inlet pipe radii and can easily change it again ifneeded, perhaps if you change the geometry or if you made a mistake when originally specifying the radius.Whenever you are asked in later tutorials to create a geometry object of a particular size, you can either set upthe grid to enable precise positioning of the geometry, or create the geometry at approximately the right sizeand then use the Dimensions Toolbox to specify the dimension exactly.

    Now you can extend the outlet pipe. The first part of the extension requires a Revolve operation. However, youneed to revolve the end surface of the existing outlet pipe, which isn't currently defined as a sketch or plane, sofirst you need to construct the appropriate plane from which to revolve.

    1.Create a new plane by using the New Plane ( ) button on the Active Plane/Sketch Toolbar, which islocated above the Model View.

    2. In the Details View, set Type to be From Face and Subtype to be Outline Plane.

    3. In the Details View, click in the box next to Base Face. There will now be two buttons, Apply and Cancel,and this means that you are ready to select the face from the Model View.

    4. In the Model View, click on the circular face at the end of the outlet pipe, which is at the position withthe lowest value of the Z-coordinate. Click on Apply in the Details View.

    5.Click on Generate to create the plane.

    The Revolve operation requires the specification of a rotation axis. Since this rotation will not be around any ofthe main coordinate axes, a sketch containing a single line to act as the required axis will be created.

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  • 1. Select the new plane Plane4 in the Tree View again, and create a new sketch based on this plane by using

    the New Sketch ( ) button on the Active Plane/Sketch Toolbar, which is located above the ModelView.

    2. Select the Sketching tab.

    3. Click on Settings (in the Sketching tab) to open the Settings Toolbox.

    4. Click on Grid and turn ON Show in 2D and Snap.

    5. Click on Major Grid Spacing and set it to 1.

    6. Click on Minor-Steps per Major and set it to 2.

    7. From the Draw Toolbox, select Line and then create a line which is parallel to the Y-axis and is positionedat x = 2 m. You can use the grid settings to position this line. The length of the line and the exact positionof its end points are not important since it is only going to be used to define a rotation axis.

    8.Select Revolve from the 3D Features Toolbar.

    9. In the Details View, click next to Base Object and then click on the name of the plane that you have justcreated (Plane4) in the Tree View. Click Apply in the Details View.

    10. In the Details View, click next to Axis and then click on the name of the sketch that you have just created(Sketch4) in the Tree View. Click Apply in the Details View.

    11. Set Angle to 60 degrees.

    12.Click on Generate to create the revolve.

    One more operation is needed to add another straight section of pipe to the outlet. This follows a very similarprocedure to the one that you have just used to create the first extension.

    1.Create a new plane by using the New Plane ( ) button on the Active Plane/Sketch Toolbar, which islocated above the Model View.

    2. In the Details View, set Type to be From Face and Subtype to be Outline Plane.

    3. In the Details View, click in the box next to Base Face. There will now be two buttons, Apply and Cancel,and this means that you are ready to select the face from the Model View.

    4. In the Model View, click on the circular face at the end of the newly revolved pipe section, which is inthe position with the lowest value of the Z-coordinate.

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    Section 2: Geometry Modification

  • 5.Click on Generate to create the plane.

    6.Select Extrude from the 3D Features Toolbar.

    7. In the Details View, click next to Base Object and then click on the name of the plane that you have justcreated (Plane5) in the Tree View. Click Apply in the Details View.

    8. Set Depth to 2 m.

    9.Click on Generate to create the extrude.

    3. Updating the Geometry in CFX-Mesh

    In this section you will make CFX-Mesh use the new geometry.

    1. At the top of the ANSYS Workbench window, you should be able to see three tabs: StaticMixer [Project],StaticMixer [DesignModeler] and StaticMixer [CFX-Mesh]. Click on StaticMixer [CFX-Mesh] to returnto the CFX-Mesh setup.

    Look closely at the Tree View. You should be able to see that many of the settings, including the top item(Model), have a green tick status symbol next to them, which means that the setup is completely valid. Thereare no yellow ticks and no red marks which indicate potential problems or an invalid setup. Any Preview Groups

    will have either a green tick ( ) or a green tick with a yellow flash ( ). In each case the green tick indicatesthat the setup is completely valid. The addition of the yellow flash indicates that the mesh which is displayedwhen you click on that Preview Group's name may not be up-to-date with the latest mesh settings i.e. you mayhave modified a setting since you last generated this surface mesh.

    1. Right-click over Geometry in the Tree View. Select Update Geometry and click on Yes on the popupmessage to continue with the update.

    The Model View will refresh to show the new geometry, with the smaller radius pipes and the longer outlet. Also,the Tree View will be updated to account for the fact that whilst most geometry faces which were originallypresent are still there, one no longer exists (the original end of the outlet pipe) and there are some new ones(the sides and end of the new section of pipe).

    1. Notice that the Tree View now shows that you have an invalid setup: various items show red exclamation

    marks ( ). The problem is that the specification for the 2D Composite Region out is invalid since theface it was applied to no longer exists.

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  • 2. Click on out in the Tree View. Select the circular face at the bottom of the mixer vessel, with the lowestvalue of the Z-coordinate.

    3. Click on Apply in the Details View.

    The model setup is now valid - the red status symbols have all gone from the Tree View.

    When you do a Geometry Update, any new faces are automatically added to the Default Preview Group and tothe Default 2D Region. This means that you do not need to update Inflated Boundary 1 to include any newfaces because it was set up to use the Default 2D Region as its location and the new faces will have been auto-matically added to this region.

    Sometimes when you do a Geometry Update, you will find that one or more yellow tick marks appear in the TreeView. This means that one or more faces was automatically removed from the corresponding meshing featuresas a result of the Geometry Update, because those faces no longer exist in the new geometry. The setup is stillvalid, however, because there is still at least one valid face used for that meshing feature. It is recommendedthat if you see yellow tick marks in your Tree View, you should check that the locations for the correspondingfeatures are what you expect.

    The geometry has been successfully updated and the CFX-Mesh setup is ready to re-mesh. At this point youcould create a new surface mesh or volume mesh. However, note that the CFX-5 example expects to use theoriginal geometry, so you should ensure that you don't overwrite the original GTM File when creating the volumemesh.

    1. Select File>Save to save the CFX-Mesh database.

    If you want to continue by working through the CFX-5 example Tutorial 2: Flow in a Static Mixer (Refined Mesh)using the newly-generated mesh, and have CFX-5.7.1 in ANSYS Workbench installed on your machine, then followthese steps:

    1. On the Project Page, a new entry will have appeared when you generated the file: Advanced CFD. Underthis entry, double-click on StaticMixerRefMesh.gtm to open up CFX-Pre.

    2. Once CFX-Pre has opened, choose File>Save Simulation As... to save the simulation as StaticMixerRef.

    3. Work through the CFX-5.7.1 tutorial, missing out the instructions in the sections Creating a New Simu-lation and Importing a Mesh.

    If you do not have CFX-5.7.1 in ANSYS Workbench installed or do not want to work through the CFX-5 example,then:

    1. Exit from ANSYS Workbench by selecting File>Exit. Choose to save all highlighted files.

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    Section 3: Updating the Geometry in CFX-Mesh

  • 34

  • Tutorial 3: Process Injection Mixing Pipe

    This example shows how to create a simple pipe junction, using Sweep to create the pipe profile. The followinggeometry and meshing features are illustrated:

    Face Spacing, for refining the mesh on a particular face;

    Inflation; and

    full surface mesh generation, to preview the full surface mesh.

    If you want to skip the geometry creation part of the tutorial, then see the instructions in Introduction to theCFX-Mesh Tutorials.

    1. Geometry Creation

    Creating the Project

    1. Open ANSYS Workbench, create a new empty project, and save it as InjectMixer.wbdb. If you need to,refer to the instructions in the Geometry Creation section of the Static Mixer tutorial for more details onhow to do this.

    2. Choose New Geometry to open DesignModeler, and specify the units as meters.

    Creating the Main Pipe

    To create the main pipe, you will use the Sweep operation. Sweep requires the use of two sketches: one definesthe profile to be swept (in this case, a circle) and the other defines the path through which the profile is swept.The profile will be created first.

    CFX-Mesh Tutorials . . SAS IP, Inc.

  • 1. Create a new plane as follows. Select the XYPlane in the Tree View and then click on the New Plane

    icon ( ) from the Active Plane/Sketch Toolbar, near the top of the ANSYS Workbench window.Clicking on XYPlane first ensures that the new plane is based on the XYPlane.

    2. In the Details View, set Transform 1 (RMB) to Offset Z, and set the Value of the offset to -4 m.

    3.Click on Generate to create the plane.

    4. Create a new sketch as follows. Select Plane4 in the Tree View and then click on the New Sketch icon

    ( ) from the Active Plane/Sketch Toolbar, near the top of the ANSYS Workbench window. Clickingon the plane first ensures that the new sketch is based on Plane4.

    5. Use Grid from the Settings Toolbox of the Sketching tab to set Show in 2D and Snap to ON.

    6. Set Major Grid Spacing to 1.0 m and Minor-Steps per Major to 2.

    7. Zoom in to the center of the grid, so that you can see the gridlines clearly. You can do this by dragginga box over the desired viewing area with the right mouse button held down.

    8. Use Circle from the Draw Toolbox of the Sketching tab to draw a circle of radius 0.5 m, centered on X =0 m, Y = -2 m. The grid settings you have just set up will help you to position the circle and set its radiuscorrectly.

    Now create the path:

    1.Create a new sketch ( ) based on the YZPlane: as before, make the YZPlane active first by clickingon it, and then use the New Sketch icon to create the sketch based upon it.

    2. Use Grid from the Settings Toolbox of the Sketching tab to set Show in 2D and Snap to ON.

    3. Set Major Grid Spacing to 1.0 m and Minor-Steps per Major to 2.

    4. Use Line from the Draw Toolbox of the Sketching tab to draw two straight lines on the sketch, as shownin the picture below.

    5. Click on Arc by Center from the Draw Toolbox, and click once on the origin (center of the Arc shown inthe picture below). Now select one of the end points of the arc, and then move the mouse round to theother end point and click on it to draw the quarter-circle. If the wrong part of the arc is drawn (i.e. a 270degree segment instead of a 90 segment) then click on Undo (from the Undo/Redo Toolbar at the topof the ANSYS Workbench window) and try again, making sure that after you click on the first end point,you move the mouse in the correct direction for the arc that is to be drawn.

    Tutorial 3: Process Injection Mixing Pipe

    CFX-Mesh Tutorials . . SAS IP, Inc.36

  • Now make the pipe itself.

    1.Select Sweep from the 3D Features Toolbar.

    2. Set the Profile to be Sketch1: click on Sketch1 in the Tree View and then click on Apply in the DetailsView at the bottom-left of the screen.

    3. Set the Path to Sketch2: click on the Not selected text next to Path, click on Sketch2 in the Tree View,and then click on Apply.

    4.Click on Generate to create the pipe.

    Creating the Side Pipe

    1.Create a new plane ( ), based on the ZXPlane: as before, make the ZXPlane active first by clicking onit, and then use the New Plane icon to create the plane based upon it.

    2. In the Details View, set Transform 1 to Offset Global Z, and set the Value of the offset to 2 m.

    3. Set Transform 2 to Offset Global Y. Set the Value of the offset to -3 m.

    4.Click on Generate to create the plane.

    37CFX-Mesh Tutorials . . SAS IP, Inc.

    Section 1: Geometry Creation

  • 5.Create a new sketch ( ) based on the new plane.

    6. Use Circle from the Draw Toolbox of the Sketching tab to create the circle centered on the origin witha radius of 0.15 m. Create the circle initially with any convenient radius, and then use Radius from theDimensions Toolbox of the Sketching tab to specify the radius more precisely, as described in the GeometryModification section of the Static Mixer tutorial.

    7.Select Extrude from the 3D Features Toolbar.

    8. Set Base Object to be the new sketch (Sketch3), and set Operation to Add Material.

    9. Set Direction to Normal and Type to Fixed. Set Depth to 3 m.

    10.Click on Generate to creat