introduction to ansys designmodeler - mr-cfd · © 2012 ansys, inc. june 13, 2013 1 release 14.5...

© 2012 ANSYS, Inc. June 13, 2013 1 Release 14.5

14. 5 Release

Introduction to ANSYS DesignModeler

Workshop 4 Geometry Cleanup and Repair


• Demonstrate the methodology for working with assembly models in DesignModeler.

• Finding geometry imperfections through various analysis tools and simplifying/repairing model.

The basic steps involved are:

1. Importing geometry file of into DM

2. Identifying geometry corruptions/issues

3. Geometry repair and defeaturing

4. Creation of fluid volume

5. Modification on extracted flow volume for ease in meshing

Objective

Compressor

Turbine

Center Housing


Launching Design Modeler • First start Workbench

• Go to Project Page Component Systems Geometry

1. Double click on Geometry Tab

2. Click Right Mouse Button (RMB) on Geometry template then click on New Geometry

1 2


Unit Selection

• DM starts with a prompt to select desired length unit. Select “Millimeter” and click OK.


Importing Geometry • Import parasolid file

turbo_charger_tutorial.x_t

– [Main Menu] File Import External Geometry File…

– Browse to file “turbo_charger_tutorial.x_t” in the Input Files folder and open it

– In Details View, select “XYPlane” as Base Plane and “Add Frozen” for Operation

– Click on “Generate” to import the model


List of Bodies imported after “Generate”

Total 10 Bodies were imported. 8 are Solids and 2 are Surfaces. Names can be seen in above image.


Changing Display Settings (1) • Turn off “Frozen Body Transparency” to view

imported bodies as Opaque

– Deselect [Main Menu] View Frozen Body Transparency

Frozen Body Transparency “ON” Frozen Body Transparency “OFF”


Changing Display Settings (2) • To see any issues in geometry change Edge Coloring

to “By Connection”

– By setting Edge Coloring to “By Connection” we can see any single or multi-connected edges

– If there are single connected edges, it means geometry is open and not a solid body. There is hole/seam/leak which needs to be closed.

– Single connected edges are displayed in Red

Edge Coloring set to “By Body Color” Edge Coloring set to “By Connection”

Single connected edges shown in Red


Sewing Surface Bodies (1)

• Select two surfaces bodies named “Surface1” and “Surface2” (see images below) to “Sew” them together

– “Sew” operation will connect two surface bodies making them one body and removing duplicate edges

– Click on [Main Menu] Create Body Operations

“Surface1” “Surface2” “Surface1” and “Surface2” shown together


Sewing Surface Bodies (2) • In Details View

– Select “Sew” for Type

– Select 2 surface bodies (select “Surface1” first and then “Surface2” to maintain name of new body as “Surface1”)

– Keep Create Solids? to “No”

– Click on “Generate” or press F5

Single surface body “Surface1” is formed after “Sew”


Closing Hole using Surface Patch

• “Surface1” is still a surface body as it has one missing face/hole as can be seen in image below

• This hole can be removed using “Surface Patch”

– Click on [Main Menu] Tools Surface Patch

– Select all 4 red edges and click “Generate”

Missing Face/Hole in surface body

Hole is patched


Converting Surface Body to Solid Body • “Surface1” is now a closed surface body and can be

converted to solid body using “Sew”

– Click on [Main Menu] Create Body Operations

– In Details View, Select “Sew” for Type

– Select the surface body

– Keep Create Solids? to “Yes”

– Click on “Generate” or press F5

– Rename “Surface1” body as “Solid9” for consistency

Solid Body Symbol shows it is a solid body


Using Repair Tools (1) • Repair tools can be used to automatically/semi-

automatically clean the geometry using certain specified criteria

• Let us search for any hard edges in the model and clean it

– Repair tools can be accessed through [Main Menu] Tools Repair

– Select “Repair Hard Edges” for identifying and cleaning hard edges in the model

– Select “All Bodies” for Bodies To Search

– Set Find Faults Now to “Yes”

– One hard edge was found. Click on “Hard Edge 1” in the Details View to zoom in to the hard edge

– Turn ON “Shaded Exterior and Edges” in View for better visibility

– Click “Generate”


Using Repair Tools (2)

Hard Edge

Hard Edge removed after “Generate”


Using Repair Tools (3) • Let us now search for any sliver faces in the

model and clean it

– Click on [Main Menu] Tools Repair Repair Slivers

– Select “All Bodies” for Bodies To Search

– Set Max Sliver Width Limit to “0.5 mm”

– Set Find Faults Now to “Yes”

– One sliver face was found. Click on “Sliver 1” in the Details View to zoom in to the sliver face

– Turn ON “Shaded Exterior and Edges” in View for better visibility

– Click “Generate”


Using Repair Tools (4)

Sliver Face

Sliver Face removed after “Generate”


Small Entity Search (1) • Now, we will search for small edges in the model. This

can be done using “Small Entity Search”

• We already know that there are small edges in turbine and compressor wheel due to thickness of blades. Similarly, there are small edges in threaded shaft, nut, washer, etc. So, we should exclude such geometries in which we do not want to clean small edges.

• So, we will select three bodies for small edge search, i.e., turbine housing, compressor casing and centre housing. These 3 bodies are shown in image below.


Small Entity Search (2) • For small entity search

– Click on [Main Menu] Tools Analysis Tools Small Entity Search

– Select 3 bodies in Entity Set

– Select “Yes” for Check for Short Edges?

– Select “No” for all other settings

– Set Short Edge Limit to “3 mm”

– Set Go! to “Yes”. It will show all short edges below 3 mm in selected bodies. In this case, there is just one edge

– Click on “Edge 1” to highlight it in Graphics View

Small Edge


Merging Small Edge • This small edge can be removed by merging it to

the adjacent edge. The two edges are shown in images below.

• To merge two edges

– Click on [Main Menu] Tools Merge

– Select “Edges” for Merge Type

– Keep Selection Method as “Manual”

– Select 2 edges and “Generate”. This will remove small edge.

First Edge (Small) Second Edge (Adjacent)


Geometry Modifications & Simplifications • There are gaps and intersections between the different solid parts of external CAD file.

• Actual geometry consists of small features like holes, fillets, threads or small faces. For CFD analysis these minute details are unwanted and can be removed.

• This simplification results in clean geometry and reduces the effort required for mesh generation and helps to maintain mesh quality.

• Figure below shows the regions where we need to work for flow volume extraction.

1

Interference

1 2

2

Gap


Enabling Beta Features

• To activate “Beta Options”, go to Workbench Schematic Page

– Go to Tools Options

– Select “Appearance” from tree

– Scroll down and enable the check box of “Beta Options”

• This will activate beta features available in the DesignModeler such as “Body Clash Detection” and “Solid Extension”


Identifying Body Interferences (1) Clash Detection

• Once you have turned on Beta Options you can now use Body Clash Detection for identifying Clashes

• [Main menu] Tools Analysis Tools Body Clash Detection (Beta)

• Select “All Bodies” for Bodies To Search

• Select “Interference” for Clash Type

• Set Go! to “Yes”. It will show all clashes in the model. In this case, there are two set of clashes.

• Click on “Clash 1” to highlight it in Graphics View


Identifying Body Interferences (2) • Switch to Wireframe view for better

viewing of clash

• [Main menu] View Wireframe

• Locate various clashes in the geometry as shown

• Both cases involve compressor casing. Adjusting/moving casing may solve problem

Interference between

compressor casing &

center housing

Interference between

compressor blades and

its casing


Measuring Amount of Overlap • Let us measure amount of overlap/clash between

compressor casing and central housing

• Revert back to Shaded view. [Main menu] View Shaded Exterior and Edges

• Hide all other bodies except these two bodies

• Measure distance between two faces (Face 1 and Face 2 shown in images) of these bodies which ideally should be mating and aligned with each other

• Distance can be measured using [Main Menu] Tools Analysis Tools Distance Finder . Select two faces to find distance between them

• It shows distance of 9 mm between faces, i.e., overlap between bodies is 9 mm. Moving compressor casing by 9 mm will solve this.

Face 1 Face 2


Removing Body Interferences • Compressor casing should be moved in -X direction

by 9mm to remove clash

• This can be done using Translate operation

• [Main menu] Create Body Operation

• Select “Translate” for Type

• Switch to body selection mode and select the compressor casing and click on “Apply”

• Select “No” for Preserve Bodies?

• Under Direction Selection select edge and direction as shown in the image

• Specify Distance of “9mm”

• Finally click on “Generate” to see the change


Filling Gaps (1) • Now we have to remove the small gap

present between center housing and turbine housing

• Again using “Distance Finder” we found that it is a 2mm gap

• We will use extrude to close this face by extruding face “Face 1” highlighted in image

• [Main menu] Create Extrude

• Select “Face 1” shown in image for Geometry

• Set Operation to “Add Frozen”

• Select edge and direction as shown in “Image 2” for Direction Vector

• Specify a Depth of “2mm”

• Keep all the other values as shown in Details View in “Image 3”

• Click on “Generate”

• A new solid body will be generated

Image 2

Face 1

Image 1

Image 3


Filling Gaps (2) • In this step we will merge the additional

body created in the previous step to the turbine casing by using “Boolean”

• The new body created is shown in “Image 1”

• [Main menu] Create Boolean

• Select “Unite” for Operation

• Select two bodies for Tool Bodies

• “Generate” it

Image 1

After Boolean Before Boolean


Geometry Simplification (1) • For CFD simulation threads of the bolt is least

important feature and can be removed using “Face Delete”

• Hide all other bodies above the bolt to view the body as shown

• [Main Menu] Create Face Delete

• Switch to face selection mode and select 3 faces which corresponds to thread (as shown)

• Click on “Apply”

• Keep Healing Method to “Automatic”

• Click on “Generate”

Face 1 Face 2 Face 3


Geometry Simplification (2)

After Face Delete Before Face Delete


Creating Capping Surfaces • For flow volume extraction we need

to close all the openings such as inlets and outlets

• We have to create surfaces to close all these openings

• We can simultaneously create four capping surfaces by selecting the edge loops to close

• We will use “Surfaces from Edges” to create these surfaces

• [Main menu] Concept Surfaces from Edges

• Select all the 8 edges of the four edge loops to create four capping faces

• Finally click on “Generate” to complete the process


Fluid Volume Extraction • Since all the openings are closed we can

use “Fill By Caps” for fluid volume extraction

• [Main menu] Tools Fill

• Select “By Caps” for Extraction Type

• Keep all other options to default

• Finally click on “Generate” to extract fluid volume

• After flow volume extraction you will get three fluid volumes as shown in images

• Unwanted flow volume can be suppressed and can be restricted getting transferred to other components


• This completes the workshop

• From the main menu select File Close DesignModeler

– Workbench will save any application data

• From the Workbench Project Page use the file menu and save the project as “DMWS4.wbpj” to your working folder

Saving the Project

introduction to ansys designmodeler - mr-cfd · © 2012 ansys, inc. june 13, 2013 1 release 14.5...

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