CFD Online Logo CFD Online URL
Home > Forums > CFX

Impeller mesh with Turbogrid and Yplus results

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   November 29, 2013, 12:21
Default Impeller mesh with Turbogrid and Yplus results
New Member
Join Date: Mar 2012
Posts: 2
Rep Power: 0
Nabu is on a distinguished road
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!
Attached Images
File Type: jpg mesh data.jpg (65.4 KB, 54 views)
File Type: jpg stg3_Yplus.jpg (35.0 KB, 49 views)
Nabu is offline   Reply With Quote

Old   November 30, 2013, 05:51
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 13,808
Rep Power: 107
ghorrocks is a jewel in the roughghorrocks is a jewel in the roughghorrocks is a jewel in the rough
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.
ghorrocks is offline   Reply With Quote

Old   October 14, 2014, 11:23
New Member
Join Date: Apr 2014
Location: Munich, Germany
Posts: 21
Rep Power: 5
krishna13j is on a distinguished road
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?

krishna13j is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 15:14.