Week 3 Challenge : CFD meshing on Turbocharger

Aim: Perform topo clean-up, surface mesh, and volumetric mesh

Procedure:

1. The model already has PIDs created
2. There is glitching present
3. 
4. To see all triple cons: Topo→Faces→Topo→select the model(Box selection)
5. 
6. Delete the pink surface using the PID region
7. Project points and create surface using coons
8. To intersect faces: Faces→Intersect
9. If faces are separated and still triple cones are present, they can be released using the release option
10. Release creates 3 single cons from a triple cone and 2 single cons from a double cone. And topo works the opposite
11. The bottom bulged-out surface is created using multiple hot points piece by piece
12. Middle click on the header of the properties toolbox is used to hide it partially
13. The errors in the model are found using check→Geometry→Evaluate
14. Check every triple cone using the iNot option and see if a triple cone is needed or not
15. Delete the surface from the cross edges if many surfaces are present
16. To cut a specific part of a PID, Project cones to that PIC is cut the desired part
17. Then use the Fine option to make the cone in the desired shape
18. The cut option can also be used to cut the desired part of a PID
19. Two closely placed single cones can be pasted together to make a double cone using the Paste option
20. Geometry must be closed to perform the volumetric option
21. The bulged surface in the bottom is not closed below, it's closed by adding a new surface
22. The upper top is also closed by creating a new surface
23. The side structure is also closed
24. After making sure the model is closed, The PIDs must be named accordingly
25. To forcefully delete: Compress→Current Desk→OK
26. Hide the bottom surface of the impeller and top surface of the blade stage _1 and make sure the shaft is see-through
27. Volumetric Mesh is followed by surface Mesh which is followed by topo clean-up
28. Some triple cons are present but no single cons are present
29. Every PID is isolated and given a 2D mesh
30. tria element type is chosen
31. Give mesh parameters and check quality criteria for different PIDs
32. Spot mesh is used for meshing
33. The outer surfaces are meshed with a 5 mm Target length first and then the rest of the elements
34. After meshing the outer surfaces impeller is meshed then the blades and shaft
35. After meshing the shaft the cylindrical surface of the impellers is getting unmeshed
36. This is caused by the sudden change of target length, 2mm of impeller, and 1mm of shaft
37. If the impeller is meshed again the neighbouring cylindrical shaft cones are unmeshed
38. To solve the issue, Select the 2 cons on the end unmeshed shaft→give perimeter as 1 mm→choose shaft PID and give macro as noting and mesh
39. This will give a gradual decrease in target length from a 2mm impeller to a 1mm shaft
40. The disrupted mesh is again made in respective places without macro specified
41. right click on the unmeshed surface written on the screen→Show only: To just see the unmeshed surface
42. See if the hidden surface is meshed if not mesh using same method
43. Additional cuts are made near the region where mesh length varies by cuts→Reconstruct→parametric cut
44. By now the surface mesh is finished
45. To define volumes: Volumes→Define→Autodetect→work on whole db→OK
46. Volumetric mesh must be done on the voids inside the model where the fluid will flow
47. 3D mesh is tetra mesh
48. A common volume is created for blades, shaft, and impeller which can be easily deleted
49. Volumes are created for the thickness of the model and for the void inside
50. Delete the volumes created for the volume of the surface of the model
51. To give volumetric mesh: Choose defined volume→Right chick→Remesh→Tetra CFD
52. Mesh all four volumes
53. The elements for volumetric mesh is way more elements than surface mesh and take a lot of time
54. Volume→List: To find the list of volumes
55. Now in topo mode, some glitching is present
56. If the volume in the toolbox situated below is unable, there will be no glitching
57. With Not option, many elements will be hidden and will take a lot of time
58. All volumes have appeared in a different colour
59. See cross section by hiding half of the entities
60. The elements are small in the intersection of surfaces and gets bigger the farther

Learning outcomes: How to do surface mush and volumetric Mesh

Result: The volumetric mesh of the turbine model is created.

Conclusion: There was glitching present to begin with. Some surfaces were deleted to avoid glitching. Checks are done. Single cones are cleared first. Release and topo are used. Then triple cones are rectified. Some parts of PID are deleted to make the volume. PIDs are assigned. Make sure the volume is closed from all sides. Perform surface mesh with different target lengths. The intersecting regions are unmeshed automatically and are meshed again without macros specified. This can be avoided by using the freeze mesh option after every mesh. Then volumes are generated and only volumes specifying the voids are kept and volumetric mesh is conducted by tetra CFD.

*Trouble in adding images cause the report is not saving. Kindly refer to the images attached.

*Unable to even send a zip file cause it's exceeding file size.

*The answer file is

https://drive.google.com/file/d/1PlLvtNOQ5xQV-J9UAiL6njOFltXXqBmY/view?usp=sharing