CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Unstructured-meshing for Unshrouded-Impeller

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 5, 2006, 09:35
Default Unstructured-meshing for Unshrouded-Impeller
  #1
Turbomachinery
Guest
 
Posts: n/a
Dear Friends,

I'd like to adopt the unstructured-mesh (using ICEM CFD tetra + prism) to unshrouded-impellers, i.e. there exists a gap between the blade-tip and the wall.

If the unstructured grid system based on tetra and prism, without hexahedral-meshing, should be applied, do the prism-layers have to be made on both the blade-tip and the shroud-wall to improve the boundary-layer resolution or on the shroud-wall only (and the tetra meshes on the blade-tip)....due to the narrow tip-clearance_^^.

I look forward to your constructive advice on it.

Thank you very much in advance...
  Reply With Quote

Old   November 5, 2006, 16:23
Default Re: Unstructured-meshing for Unshrouded-Impeller
  #2
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

It is generally best to have full inflation/prism layers, but you may be able to use a tet mesh only right at the blade end. You will have to try it on your geometry and establish for yourself whether it is sufficient.

Glenn Horrocks
  Reply With Quote

Old   November 5, 2006, 18:28
Default Re: Unstructured-meshing for Unshrouded-Impeller
  #3
Turbomachinery
Guest
 
Posts: n/a
Thank you for relying to my query....

There is a tip-clearance (relatively small-gap comparing with other geometric dimension, e.g. diameter) and we are going to construct the 'tetra+prism' on the the stationary wall, the blade-tip and blade, and the hub surface.

Under the circumstances, if the total heights for the prism-layers be different due to the tip-clearance, the mesh structure could not be properly distributed for the computational domain, i.e. not uniformly distributed!

In case, the user's manual says that there are at least 2-3 tetrahedral meshes between the prism-layers.

How could I overcome this kind of problem...? (In this case, I wonder if the hexahedral-meshing should be adopted or not.)

Thanks a lot in advance.
  Reply With Quote

Old   November 6, 2006, 16:10
Default Re: Unstructured-meshing for Unshrouded-Impeller
  #4
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Sounds like you either need to use a smaller initial height in the tip region. You could also mesh this in a hexahedral mesher but with a little thought a tet/prism mesh should work.

Glenn Horrocks
  Reply With Quote

Old   November 7, 2006, 03:54
Default Re: Unstructured-meshing for Unshrouded-Impeller
  #5
Turbomachinery
Guest
 
Posts: n/a
Dear Friend,

Could you make the prism-layers with good quality on both the blade-tip and the blade-around surfaces?

Due to the small gap between the blade-tip and the stationary wall, the total thickness of prism-layer on the blade-tip becomes very thin comparing with the prism-layer's thickness of the blade-around surface, which makes the whole structure of the prism-layers be irregular, i.e. the total thickness of each prism-layer may be different from the one designated by the user.

How could you handle this problem...?

With my best regards,
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[ICEM] Hexa meshing of impeller and diffuser assembly Nitin Dewangan ANSYS Meshing & Geometry 14 September 13, 2016 10:41
[ICEM] Meshing a centrifugal compressor impeller Mitpostdoc ANSYS Meshing & Geometry 8 February 25, 2011 11:51
Best Search algorithm for Unstructured Meshing? Dinesh Godavarty Main CFD Forum 3 September 3, 2003 14:16
how to do a good meshing using unstructured mesh nikita FLUENT 6 August 22, 2003 22:06
unstructured meshing Michelle FLUENT 1 February 7, 2003 06:23


All times are GMT -4. The time now is 10:10.