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Nabu November 29, 2013 12:21

Impeller mesh with Turbogrid and Yplus results
2 Attachment(s)
Hello everybody,

i'm using CFX 14.5.7 to simulate one stage of a centrifugal compressor. I used Turbogrid to mesh the impeller passage. Attached is the minimum errors that i could achieve playing with factors inside mesh data.

The simulation reached acceptable value for residual RMS error (less than 10^-4), but Yplus is more than 300.

Is there anyone who has suggestions or comments to improve Yplus result?
I did not use tip clearance on shroud because i saw that by introducing a clearance at shroud the errors in the mesh increase. But i would like to ask if is reasonable to model the clearance in the mesh and if someone has experience of meaningful results.

Thanks for any help!

ghorrocks November 30, 2013 05:51

Do not simply assume that a big y+ means your simulation is bad. You should do a mesh sensitivity check and find out whether it is a problem or not.

And also do not assume your convergence is acceptable either. You should check that as well.

krishna13j October 14, 2014 11:23

Hi Nabu,

I am doing a similar simulation and developed the mesh for a passage using Turbogrid but am stuck after the single passage analysis. I have completed the single passage analysis but my work requires to model a full stage centrifugal compressor. Can you please help me with this. Is this done in ICEM CFD or can it be doen directly in CFX-Pre.

Also, I have an inlet pipe geometry which I need to connect to the full stage mesh. Do I need to develop a united geometry in design modeller or would it be fine if I model it separately and then import it to CFX-pre after meshing in ANSYS meshing tool?


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