aim r16 ws01 exhaust manifold

7/23/2019 AIM R16 WS01 Exhaust Manifold

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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.

1Release 16.0 - SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationof ANSYS, Inc. and its subsidiaries and affiliates.


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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.

Release 16.0 - SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationof ANSYS, Inc. and its subsidiaries and affiliates.2

Model Configuration and Meshing


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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.


Setup And Solution


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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,


Summary


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2. Assemble and configure the geometries,

3. Create mesh for fluid analysis


aim r16 ws01 exhaust manifold

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