[ICEM] Geometry Tolerance and meshing

Mitpostdoc · May 26, 2011, 18:01

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

.

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?

May 26, 2011, 18:01	Geometry Tolerance and meshing	#1
Mitpostdoc New Member Claudio Join Date: Feb 2011 Posts: 20 Rep Power: 15	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 . 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

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June 6, 2011, 08:34		#2
jeevankumarb Member jeevan kumar Join Date: Mar 2009 Posts: 88 Rep Power: 17	If you can upload the tetin and the blocking file then i will have a look and can suggest you. regards jeevan

June 6, 2011, 10:33		#3
seaharrier New Member Join Date: Jun 2009 Posts: 11 Rep Power: 17	why don't you use turbogrid to mesh your compressor?

June 6, 2011, 11:03		#4
Mitpostdoc New Member Claudio Join Date: Feb 2011 Posts: 20 Rep Power: 15	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!!!

January 1, 2012, 13:51		#5
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	got any solution?