Stage interface doesn't work as intend?

sheaker · July 4, 2018, 05:40

Dear CFX Users,
I'm using CFX 16 and I'm facing strange behavior of stage interface in CFX Turbomachinery simulation of Axial Turbine. I believe it could be cause by mesh or bad settings. Please, see the attachments.
velocity1.png and mesh1.png shows velocity and mesh on the stator side of interface.
velocity2.png and mesh2.png shows circumferential averaged velocity and mesh on the rotor side of interface.

I do not really understand why there is such a large region with close-to-zero velocity on the rotor side.

I will appreciate any suggestions,
Oskar

Ludvik · July 9, 2018, 04:25

Increase number of circumferential bands.

EXPERT PARAMETERS:
force intersection = t
ggi stage groups max = 250
END

sheaker · July 9, 2018, 10:59

Dear Mister Ludvik.
I haven't tried it yet but I think You are right. I'm going to try it as fast as possible to ensure Your solution is right.
Thank Your very much.
Sheaker

sheaker · December 17, 2018, 13:05

Dear Ludvik,
after many attempts I still don't now where to set "ggi stage groups max = 250".

Could You possibly point me where to set it?

Best regards,
Oskar

ghorrocks · December 17, 2018, 15:50

It is an expert parameter. Not all expert parameters are on the CFX-Pre GUI, many are CCL only. If you use Ludvik's CCL in your CCL it should work.

sheaker · December 17, 2018, 16:20

Quote:

Originally Posted by ghorrocks

It is an expert parameter. Not all expert parameters are on the CFX-Pre GUI, many are CCL only. If you use Ludvik's CCL in your CCL it should work.

Thank You for Your answer, horrocks. I'm going to set it in CCL. (I don't know how to do it yet but I think I can figure it out by myself.)

Regards,
Oskar

I think it does not resolve my problem. I have created CCL file:

Code:

FLOW: Flow Analysis 1
  EXPERT PARAMETERS:
    force intersection = t
    ggi stage groups max = 250
  END
END
COMMAND FILE:
  Version = 16.0
END

and load it to CFX but results are exactly the same.

July 9, 2018, 10:59		#3
sheaker Senior Member Oskar Join Date: Nov 2015 Location: Poland Posts: 184 Rep Power: 10	Dear Mister Ludvik. I haven't tried it yet but I think You are right. I'm going to try it as fast as possible to ensure Your solution is right. Thank Your very much. Sheaker __________________ How to set two stroke engine with scavenging? Salome, sliding interface and "Zero length edge detected."

December 17, 2018, 13:05		#4
sheaker Senior Member Oskar Join Date: Nov 2015 Location: Poland Posts: 184 Rep Power: 10	Dear Ludvik, after many attempts I still don't now where to set "ggi stage groups max = 250". Could You possibly point me where to set it? Best regards, Oskar __________________ How to set two stroke engine with scavenging? Salome, sliding interface and "Zero length edge detected."

December 17, 2018, 15:50		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	It is an expert parameter. Not all expert parameters are on the CFX-Pre GUI, many are CCL only. If you use Ludvik's CCL in your CCL it should work. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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July 9, 2018, 04:25		#2
Ludvik Member Join Date: Apr 2009 Location: Czech Republic Posts: 65 Rep Power: 18	Increase number of circumferential bands. EXPERT PARAMETERS: force intersection = t ggi stage groups max = 250 END