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-   -   [ICEM] Geometry Tolerance and meshing (http://www.cfd-online.com/Forums/ansys-meshing/88820-geometry-tolerance-meshing.html)

Mitpostdoc May 26, 2011 18:01

Geometry Tolerance and meshing
 
Hello there.
I worked for the past 2 months on the meshing of a very complex centrifugal compressor. After many days of frustration with Icem I managed to have a clean and smooth structured mesh of the geometry. However, whenever I try to refine it, I have negative determinants everywhere :(.

I am trying to do a CFD simulation of a high pressure compressor with supercritical CO2. The Re is very high and the estimated cell size in order to have a reasonable y+ near the wall is between 1 and 0.1 microns :eek:.

I tried to repair the geometry several times with icem, but even if I set the model tolerance and triangulation tolerance to 10^-07 I still can not fix it. Moreover, since Icem lacks of proper methods to define periodic planes, I had to manually crate all the periodic boundaries. Needless to say that all the geometric entities I created share the same tolerance of the geometry.

Is there anybody who can help me? Does anybody have any experience with this kind of issue?

thanks

jeevankumarb June 6, 2011 08:34

If you can upload the tetin and the blocking file then i will have a look and can suggest you.

regards
jeevan

seaharrier June 6, 2011 10:33

why don't you use turbogrid to mesh your compressor?

Mitpostdoc June 6, 2011 11:03

Hello there!!!
Thank you very much for the reply.

Unfortunately I am not allowed to disclose any of the geometry file as they belong to the industrial sponsor :(. Very sad, I know. Is there any way I can provide some information without giving up rights on the geometry file? In particular, I was trying to generate planes and lines in Icem. Even if I specify very small tolerance I can still see that lines and surfaces are not perfectly matching. Even if I keep tolerance to 10e-07 I can't refine the mesh to 10e-06 without having cells falling into the gaps.

I actually thought about Turbogrid... but I am not sure how I can generate the initial file to be imported: The geometry I am working on is fairly complicated with seal passages and leakage flows. I have a STEP and parasolid file of the whole geometry. How do I generate the initial file to be imported in Turbogrid?

Thanks a lot for your help!!!

Far January 1, 2012 13:51

got any solution?


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