To clean all topological errors and mesh the given turbocharger model using ANSA

Objectives:

To clean all topological errors and mesh the given turbocharger model using ANSA.

Procedure:

1) Import the geometry and performing geometry cleanup.

2) Setting up properties (PIDS).

3) Create surface mesh.

4) Create volume mesh.

1)Import the geometry and performing geometry cleanup

Open ANSA software and write performance_mode 3 in the other Additional ANSA command arguments in the popup window.

Import turbocharger file in ANSA.

check for geometry errors of the model.

As shown in the figure there are lots of topological errors in the geometry which has to be fixed before performing the meshing operation.

Check for topological errors for the given model through utility window or turnoff the shadow mode (use ctrl+shift to turnoff shadow mode temporally) to see single cons and triple cons(which tends to error).

Use Not, Universal delete, coons, fitted, hot points (by spilling the surfaces), project, intersect command to clear all the topological errors,

NOT- to hide the surface for proper viewing of the error.

DELETE- to delete the overlapping surface.

Coons- to define a new surface by its boundary curves.

Fitted- to create a surface that fits between the selected boundaries.

Hot points- to split the con.

Project- to project the cons on the selected surface.

Intersect- to intersect the surface.

make a geometry check to make sure every topological error is removed.

Make blade stage 1, stage 2 and impeller shaft rotor to a common volume by using topo project delete commands.

Remove the intersection surface

2)Setting up properties (PIDS)

To assign the property to the model we need to select TOPO Mode (upper right of the menu toolbox).

• Go topo Mode.
• Under face sub-menu.
• Selected set-PID option.
• Select face/shell.
• GO to below bar and select cross hatches option it enables diagonal of the model.
• Left click on cross hatches then middle click of your mouse.
• A shell properties help box will appear.
• Select new option tab, a box will apear, create a New ID name of the specific part (for exiled)
• Click ok then in shell properties help box double click on New Id (inlet) to assign it to the specific part of the model.
• Same procedure will be followed for each of the parts of the mode.

3)Create surface mesh

As there are no geometrical errors present in the model and the properties are also assigned to the model so it is ready for the meshing, steps for meshing are as follows:

For meshing the model, we need to go to mesh module

• Select mesh module
• Under perimeter sub-menu
• Select length (to decide the length of the mesh discritization's)
• By left click draw a box around the valve, all points of the valve will get selected
• Click middle button of mouse a length parameter box will apear, insert the numeric value 2mm,
• click ok

Now we will start with meshing

• Select Mesh module
• Under mesh Generation
• Select spot mesh by clicking left mouse button
• Right side below one option list drop menu will element type select tria
• By using left mouse button draw a box around the valve model
• Click the middle mouse button to conform your selection
• Mesh will be generated.

Assign element size for each of the component as follows:

Blade stage 1 and 2, shaft rotor- 1mm

Impeller- 2mm

Compressor casing, inlet casing, turbo casing- 5mm

*Mesh the entire turbocharger by mesh generation function.

But after close observation we came to know that at component changes over time meshing doesn't happen uniformly since element size for each component varied.

Make a patch at the joints using Mark/ UN option for an element size of 3mm so that mesh size won't decrease gradually.

4)Create volume mesh

• Switch to mesh mode in the utility window.
• Go to define tab in volumes to get availabe volume.
• Keep the volumes needed and delete the rest
• creat a volumetric mesh forthe needed by using unstructured mesh- TETRA CFD

Conclusion:

Surface and volumetric mesh is done for given turbocharger model after cleaning all the topological errors.

https://drive.google.com/open?id=1VaeRhjZ3eio5OVzVTzaM9b8MPWLIkL-e