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Chapter 1: Model Configuration and Meshing
This tutorial demonstrates how to assemble and configure two geometries for fluid flow in ANSYS AIM.
In this tutorial you will learn how to
Launch ANSYS AIM.
Import multiple geometries.
Assemble and configure the geometries.
Create computational mesh.
1.1. PrerequisitesThis tutorial assumes that you have limited experience with ANSYS AIM so each step will be explicitly
described.
1.2. Problem Description
In this tutorial you will assemble and configure an exhaust manifold. The exhaust ports and catalyst
will be separately imported. The configuration task is used to assemble the geometries.
1.3. Setup And Solution
The following sections describe the setup and solution steps for this tutorial:
1.3.1. Preparation
1.3.2. Starting AIM
1.3.3. Geometry
1.3.4. Model Configuration
1.3.5.Volume Creation
1.3.6. Mesh
1.3.1. Preparation
1. Create a working folder on your computer.
2. Copy the files (exhaust_catalyst.x_tand exhaust_runners.x_tto the working folder.
1.3.2. Starting AIM
In this step you will start ANSYS AIM and set up a simulation process.
1. From the Windows Startmenu, select Start > All Programs > > ANSYS 16.0 > ANSYS AIM 16.0to start
a new ANSYS AIM session.
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The ANSYS AIM application window will appear. The various Simulation Process Templatesare
displayed in the Studypanel at the left. The Helpwindow is displayed on the right-hand side. It
contains links to instructional videos and the Helpmenu. The Workflow tab is displayed at the
bottom.
2. Ensure that the unit is set to Metric (kg,m,s,C,A,N,V).
Home( ) > Units> Metric (kg,m,s,C,A,N,V)
1.3.3. Geometry
1. In the Studypanel click on Import Geometryin the group Additional Creation Methodsunder Simu-
lation Process Templates.
Click Choose File...and select the files (exhaust_catalyst.x_tand exhaust_runners.x_t
from your working folder and click Open.
The catalyst assembly and exhaust manifold geometries are imported.
Note
Click on the Zoom to fit icon to display both the catalyst and exhaust manifold
assemblies.
2. In the Geometrypanel click on Addunder Connected Tasksand select Model Configuration.
The first task you will do is to assemble the catalyst assembly with the port assembly.
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1.3.4. Model Configuration
1. Now you need to assemble and configure the geometry.You can do this by either:
Clicking on Geometrycell > Add Next> in the Workflowtab.
Clicking on Add > Model Configurationin the Geometrypanel under Connected Tasks.
RMB in the graphics window and clicking on Add Next Task> Model Configuration.
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2. In the Configurationpanel click the blue lightning bolt near the top of the panel, or the Configurebutton
at the bottom, or RMB on the Configurationcell under the Workflowtab, or by RMB inside the graphics
window and selecting Configurefrom the context menu..This will load the geometries for configuration
3. In the Configurationpanel click Addnext to Configure Controlsand select Move/Rotate Controlfrom
the drop-down list.
a. Enable Body selection( ).
b. Click Shiftand drag a square around the catalyst geometry to select all. Click on the +button ( )
next to Part Selectionsin the Move/Rotate Controlpanel.
c. Select Create Newfrom the Replacement Origindrop-down list.
d. In the Reference Framepanel click Add Transformationunder Transformationand select Rotate
from the drop-down list.
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i. Click on the box next to Rotateto expand the list.
ii. Retain Localfor Relative to.
iii. Enter 45 [degree]for Rotation Angle.
iv. Retain Cartesianfrom the Coordinate typedrop-down list.
v. Enter 0,1,0for X, Y, and Zrespectively under Cartesian.
vi. Similarly add three more transformations. The settings are as shown in theTable 1.1: Transform-
ation Settings (p. 5).
Table 1.1: Transformation Settings
Cartesian DirectionRotation Angleor
Magnitude
Relative toTransformation
0,1,045 [degree]LocalRotate
0,0,-190 [degree]LocalRotate
1,0
,00.5
[m]ParentTranslate0,0,-10.8 [m]ParentTranslate
Note
You can update Configurationafter every transformation to see the effect of
the transformation on the geometries. After rotating you can check the approx-
imate distance between the geometries with the scale in the graphics windows.
You can see that it is equal to the values you entered for Magnitude.
vii. Right click on Configurationbutton in the Workflowtab and select Updatefrom the contextmenu. You can see that the catalyst is now assembled with the exhaust port.
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4. There are some bodies you do not need for the fluid simulation so you will be suppressing them now.
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a. Enable Body selection( ). Select all the remaining bodies other than the pipes and sensor bodies.
(See Figure 1.4: Sensor openings (p. 17).This figure shows the sensor bodies which should not be
suppressed.)
b. Right click and select Add> Configure Controls> Suppress Control
c. Right click on the Configurationcell in the Workflowtab and click Update.
Note
If after updating you find that some unwanted bodies are still there you can select
them and add them to Part Selections in the Suppress Controlpanel.
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d. There is a porous part inside which also needs to be suppressed. Hide the body as shown in the Fig-
ure 1.1: Hide body to reveal porous bodies (p. 9).
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Figure 1.1: Hide body to reveal porous bodies
e. Select the porous bodies beneath and add them to Part Selectionsin the Suppress Controlpanel.
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f. Right click on the Configurationcell in the Workflowtab and click Update.
5. If you zoom in on the bodies covering the porous parts as shown in Figure 1.2: Zoom-in view of leak (p. 11),
you can see that they are not aligned perfectly. There is a gap between them which can lead to a leak.
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Figure 1.2: Zoom-in view of leak
To remove the gap you will translate the two bodies slightly. The wrap operation will cover thegap.
a. Return to the Configurationpanel, click Addnext to Configure Controlsand select Move/Rotate
Controlfrom the drop-down list.
b. Select the upper part as shown in the Figure 1.3: Translate (p. 12)and add to Part Selections.
c. Select Create Newfrom the drop-down list of Replacement originin the Move/Rotate Control
panel. A Reference Framepanel opens.
d. In the Reference Framepanel select Reference 1from the Relative todrop-down list.
e. Click Add Transformationunder Transformationand select Translatefrom the drop-down list.
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Figure 1.3: Translate
f. Click on the box next to Translateto expand the list.
g. Select Parentfrom the Relative todrop-down list.
h. Retain the selection of Magnitude and directionfor Define by.
i. Enter 7e-4 [m]for Magnitude.
j. Retain the selection of Cartesianfor Coordinate type.
k. Enter 1for Xunder Cartesian.
l. Right click on the Configurationcell in the Workflowtab and click Update.
You can see that the upper part has moved down slightly.
m. Similarly translate the lower part upwards along with the sensor body (there are 2 parts of sensor
body, ensure to include both), in the same magnitude. Enter -1for Xunder Cartesiansince you
need to move the part upwards.
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You can see after the update that the two parts are not properly aligned and that there is no
leak.
6. Now you will create capping surfaces for the volume wrapping operation. Return to the Configuration
panel, click Addnext to Construction Geometryand select Capping Surfacefrom the list.
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a. Rename the Capping Surfacepanel to in1
b. Ensure that Create selection setis enabled.
c. Enable Face Selection ( ). Select the rim face of the first pipe.
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d. Add it to Facesby clicking on the +( ) sign next to text box.
The in1panel updates and a cap is created on one inlet pipe.
e. Similarly create caps on the rest of the three inlet pipes.
f. Now add a capping surface to the outlet pipe, out.
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g. Right click on the Configurationcell in the Workflowtab and click Update.
This creates capping surfaces for the inlets as well as the outlet.
h. Expand Construction Geometryin the Configurationpanel by clicking >next to it. Click on Capping
Surface.
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You can see that the selection sets have been created. These can be used later for setting boundary
conditions.
7. There are two tiny openings on the side which would also need to be capped. See Figure 1.4: Sensor
openings (p. 17). These are the sensor openings.
Figure 1.4: Sensor openings
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a. Enable Body selection( ). Hide the body next to the sensor opening by selecting it, RMB and
selecting Hide Bodyfrom the context menu.
b. Enable Face Selection ( ). On the inner side of the tube of the sensor opening select the two
faces as shown in Figure 1.5: Capping Sensor Opening (p. 18). RMB Add> Construction Geometry
> Capping Surface
Figure 1.5: Capping Sensor Opening
c. Now right click in the graphics window and select Show Allfrom the context menu.
d. Disable Create selection setin the Capping Surfacepanel that opens.
Note
Disabling Create selection setensures the set can be detected automatically for
inflation and for wall boundary.
e. After everything is visible, you can see a gap in the area surrounding the sensor enclosing boundary.
See Figure 1.6: Capping the surrounding gap (p. 19).To close the gap select the two faces which
surround the sensor enclosure, RMB Add> Construction Geometry> Capping Surface
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Figure 1.6: Capping the surrounding gap
f. Disable Create selection setin the Capping Surfacepanel that opens.
g. Similarly close the gaps on bothe sides of the other sensor enclosure by capping.
h. Right click on the Configurationcell in the Workflowtab and click Update.
8. This completes the fluid flow configuration task.
9. Save the project Exhaust_manifold.
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1.3.5.Volume Creation
1. Now you need to wrap the geometry.You can do this by either:
Clicking on Configurationcell > Add Next> Volume Creationin the Workflowtab.
Clicking on Add > Volume Creationin the Geometrypanel under Connected Tasks.
RMB in the graphics window and clicking on Add Next Task> Volume Creation.
2. In the Volume Creationpanel, click on Addnext Volume Definitionsand select Extracted Volume.
In the Extracted Volumepanel you can see that you need to create a point inside the flow region.
a. Click Create new.
b. With the help of the triad axis, move the point such that it resides in the flow domain.
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3. Return to Volume Creationpanel and disable Use predefined settings.
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a. Expand Global Sizingby clicking on it.
b. Enter 0.002 mfor Minimum sizeand Proximity minimum size.
c. Enter 0.1725 mfor Maximum size.
d. Select Faces and edgesunder Proximity size function sources.
e. Under Objects, click on Addnext to Size Controlsand select Face Sizingfrom the list.
i. Box select over both the sensor bodies to select all the faces. (Press Shiftand drag the mouse
over the body. Ensure that the box encloses the sensor body on all sides.)
ii. Click on the arrow button for Locationto replace the default selected faces.
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iii. Enter 2e-4 mfor Element size
iv. Select Hardfrom the Behaviordrop-down list.
Note
If the Behavior is not displayed in the panel then click the Show all properties
icon at the top of the panel.
4. Right click on Volume Creationcell in the Workflowtab and select Update.
Note
Depending upon the speed of your computer this process may take a few minutes to
complete.
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This will create a wrap. Click on the Volume Creationcell in the Workflow tab and check the wrap
mesh by click on the Show Meshbutton .
5. Save the project.
1.3.6. Mesh
1. Now you need to mesh the geometry.You can do this by either:
Clicking on Volume Creationcell > Add Next> Meshingin the Workflowtab.
Clicking on Add > Meshingin the Volume Creationpanel under Connected Tasks.
RMB in the graphics window and clicking on Add Next Task> Meshing.
2. In the Meshpanel click Addnext to Mesh Controlsand select Inflation.
a. In the Inflationpanel enable Automatically defined
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b. Select First layer thicknessfrom the Inflation optiondrop-down list.
c. Enter 1e-4 mfor First layer height.
d. Enter 5for Maximum layers.
3. Generate the mesh by clicking on either the blue lightning bolt near the top of the Meshpanel, the blue
lightning bolt near the bottom of the Meshpanel, the Update option under the Workflowtab, or byRMB inside the graphics window and selecting Generate Meshfrom the context menu.
Note
Depending upon the speed of your computer this process may take a few minutes to
complete.
4. Save the project.
1.4. Summary
With ANSYS AIM interface assemble and configure geometries for fluid simulation.
1. Import CAD geometries,
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2. Assemble and configure the geometries,
3. Create mesh for fluid analysis
Model Configuration and Meshing