[Other] TurboGrid - problem with trailing edges ending with hub/shroud curve

TTM · January 25, 2012, 11:47

Dear cfd-online community

I am currently trying to create a mesh for a centrifugal pump impeller using TurboGrid:

sketch
http://www7.pic-upload.de/25.01.12/tfn9jdb4cgib.jpg

My problem is that the trailing edges of the impeller end on the same radial coordinates as the hub an shroud curves (please see sketch).
Furthermore I need an outlet domain where I can define interfaces to the volute and the side wall gaps (like on the sketch).
TurboGrid creates a valid geometry (including the outlet domain) with the curves I provide but when it comes to meshing TurboGrid meshes the outlet domain as an extension of hub and shroud (so I have no domain in which I can set up the interfaces to the side wall domains).
If I move the outlet domain marker (the white diamonds) so that the outlet domain begins immediately after the trailing edges TurboGrid creates inverted elements on the surface between the trailing edges.

None of the tutorials or thesis I found in which TurboGrid was used included such an impeller geometry.
Is it even possible to create a mesh with TurboGrid where the hub/shroud end the way they do in my case? Is there any error source I am overlooking?

Thanks in advance

Far · January 25, 2012, 12:20

please post pics of turbogrid where you are getting problem

TTM · January 26, 2012, 04:35

Thanks for your quick reply.

Here is a picture showing the inverted elements near the trailing edges:

http://www7.pic-upload.de/26.01.12/xk91s6ydbdoc.jpg

Far · January 26, 2012, 10:50

1) Extend your hub/domain few percents (atleast, but ideally should be mid way between two components and shall be used as interface) of chord to provide room to turbo-grid for its proper working.

2) You need to provide special instructions in turbogrid and turbogrid file for treating the flat trailing edge. Have you done this?

TTM · January 26, 2012, 20:11

I found a solution to this matter.

I had to change the hub/shroud curve approximation from bspline to piece wise linear and then check "line of rotation on hub and shroud" at the trailing edge definition field.

cfdnoob · May 13, 2015, 12:08

thanks......

saeidghouli · March 13, 2016, 16:07

Quote:

Originally Posted by TTM

I found a solution to this matter.

I had to change the hub/shroud curve approximation from bspline to piece wise linear and then check "line of rotation on hub and shroud" at the trailing edge definition field.

Dear TTM
Thank you for your helpful post....
But I really couldn't understand your last reply....Could you explain more about ((change the hub/shroud curve approximation from bspline to piece wise linear and then check "line of rotation on hub and shroud" at the trailing edge definition field))??
and Where should I do all this? in DM or Turbogrid?

meronena · June 7, 2016, 09:14

Hi

I seem to have the same problem. No use in changing the curve approximations or ticking the "line of rotation on hub and shroud"-option.

Is there a way to keep the geometry so that the blades' trailing edges are coincident with the impeller's outlet-domain, or does one indeed need to increase the hub/shroud curves?

Avenger · February 16, 2020, 08:11

My error shows like this:-
#Blade 1 boundary layer control error# while meshing centrifugal pump impeller in turbogrid.

Kindly suggest me what parameters to vary? I have no idea as of now, how to rectify this error, so that I can proceed for simulation.
Basically, I will be simulating For Slurry pump after this meshing can be corrected.
It would be great help if somebody can correct this?

January 25, 2012, 11:47	TurboGrid - problem with trailing edges ending with hub/shroud curve	#1
TTM New Member Join Date: Jan 2012 Posts: 3 Rep Power: 14	Dear cfd-online community I am currently trying to create a mesh for a centrifugal pump impeller using TurboGrid: sketch http://www7.pic-upload.de/25.01.12/tfn9jdb4cgib.jpg My problem is that the trailing edges of the impeller end on the same radial coordinates as the hub an shroud curves (please see sketch). Furthermore I need an outlet domain where I can define interfaces to the volute and the side wall gaps (like on the sketch). TurboGrid creates a valid geometry (including the outlet domain) with the curves I provide but when it comes to meshing TurboGrid meshes the outlet domain as an extension of hub and shroud (so I have no domain in which I can set up the interfaces to the side wall domains). If I move the outlet domain marker (the white diamonds) so that the outlet domain begins immediately after the trailing edges TurboGrid creates inverted elements on the surface between the trailing edges. None of the tutorials or thesis I found in which TurboGrid was used included such an impeller geometry. Is it even possible to create a mesh with TurboGrid where the hub/shroud end the way they do in my case? Is there any error source I am overlooking? Thanks in advance

January 26, 2012, 10:50		#4
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	1) Extend your hub/domain few percents (atleast, but ideally should be mid way between two components and shall be used as interface) of chord to provide room to turbo-grid for its proper working. 2) You need to provide special instructions in turbogrid and turbogrid file for treating the flat trailing edge. Have you done this? saeidghouli likes this.

January 26, 2012, 20:11		#5
TTM New Member Join Date: Jan 2012 Posts: 3 Rep Power: 14	I found a solution to this matter. I had to change the hub/shroud curve approximation from bspline to piece wise linear and then check "line of rotation on hub and shroud" at the trailing edge definition field. saeidghouli likes this.

May 13, 2015, 12:08	Turbogrid Trailing Edge Problem	#6
cfdnoob New Member Rich Join Date: Jul 2014 Posts: 23 Rep Power: 12	thanks...... Last edited by cfdnoob; May 14, 2015 at 13:39.

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January 25, 2012, 12:20		#2
Far Senior Member Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,558 Blog Entries: 6 Rep Power: 54	please post pics of turbogrid where you are getting problem

January 26, 2012, 04:35		#3
TTM New Member Join Date: Jan 2012 Posts: 3 Rep Power: 14	Thanks for your quick reply. Here is a picture showing the inverted elements near the trailing edges: http://www7.pic-upload.de/26.01.12/xk91s6ydbdoc.jpg

June 7, 2016, 09:14		#8
meronena New Member A. Meronen Join Date: Jun 2016 Posts: 1 Rep Power: 0	Hi I seem to have the same problem. No use in changing the curve approximations or ticking the "line of rotation on hub and shroud"-option. Is there a way to keep the geometry so that the blades' trailing edges are coincident with the impeller's outlet-domain, or does one indeed need to increase the hub/shroud curves?

February 16, 2020, 08:11		#9
Avenger New Member Avenger fan Join Date: Feb 2020 Posts: 1 Rep Power: 0	My error shows like this:- #Blade 1 boundary layer control error# while meshing centrifugal pump impeller in turbogrid. Kindly suggest me what parameters to vary? I have no idea as of now, how to rectify this error, so that I can proceed for simulation. Basically, I will be simulating For Slurry pump after this meshing can be corrected. It would be great help if somebody can correct this?