[TGrid] Topology-error

snost · November 25, 2015, 08:36

Hello,

I am trying to mesh the fluid volume of a radial compressor with turbogrid. After preparing the hub, the shroud and the blade geometry of main-blade and splitt-blade with the Ansys Design Modeler, I wanted to mesh the volume in turbogrid. The geometry seems to be loaded correctly, but the topology fails with the following Error:

ERROR
An error was thrown while generating the span geometry for Topology.
This probably means the selected topology is not appropriate. Details are given below:
U value outside ot its bounds. Value =-0.243

How can I solve this problem?

Thank you for your answers.

-Maxim- · November 27, 2015, 04:44

I think I had a similar error before. In my case, part of my blade was cutting through in the inlet/outlet interface of the TurboGrid.
So I would suggest you double-check the geometry (location of inlet/outlet/hub/shroud) - maybe give the TG mesh some more space around the blade.

It would maybe also help to post a screenshot of your geometry in Ansys Design modeler

h.alavi1990 · May 29, 2016, 17:26

Hello,
I'm trying to mesh a radial turbine (with splitters) Using TurboGrid, I have exported the geometry of blades and splitters using Design Modeler via two separate ExportPoints features for blades and splitters.
Here is where I'm stuck:
1. When I try to mesh the turbine with both blades and splitters, I get the same topology error which is discussed in this topic.
2. I can mesh a turbine with just blades, or just splitters which seems to mean that the curves don't have any problems and topology constraints is the cause of error.
3. I changed the the place of leading edge and trailing edge and meshed the geometry as a centrifugal compressor, this resulted to a nice mesh without even a warning!

Is it possible that I use the compressor mesh and correct it by boundary conditions in the next step?
Would this effect the validity of results?

Bdew8556 · March 4, 2020, 08:59

Hey all,

Any resolution to this?

Im trying to add a second splitter to a compressor model and that seems to be triggering the error the first poster described/.

causuya · September 21, 2020, 23:51

try change the rotation direction, it works on my cases sometimes.

GoodZhaoBo · July 25, 2023, 15:51

Quote:

Originally Posted by causuya

try change the rotation direction, it works on my cases sometimes.

This is correct. It works for me!

November 25, 2015, 08:36	Topology-error	#1
snost New Member Konstantin Zitrus Join Date: Nov 2015 Posts: 1 Rep Power: 0	Hello, I am trying to mesh the fluid volume of a radial compressor with turbogrid. After preparing the hub, the shroud and the blade geometry of main-blade and splitt-blade with the Ansys Design Modeler, I wanted to mesh the volume in turbogrid. The geometry seems to be loaded correctly, but the topology fails with the following Error: ERROR An error was thrown while generating the span geometry for Topology. This probably means the selected topology is not appropriate. Details are given below: U value outside ot its bounds. Value =-0.243 How can I solve this problem? Thank you for your answers.

September 21, 2020, 23:51		#5
causuya New Member Andreas Sun Join Date: Jul 2012 Posts: 4 Rep Power: 13	try change the rotation direction, it works on my cases sometimes. Bak16 likes this.

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November 27, 2015, 04:44		#2
-Maxim- Senior Member Maxim Join Date: Aug 2015 Location: Germany Posts: 415 Rep Power: 12	I think I had a similar error before. In my case, part of my blade was cutting through in the inlet/outlet interface of the TurboGrid. So I would suggest you double-check the geometry (location of inlet/outlet/hub/shroud) - maybe give the TG mesh some more space around the blade. It would maybe also help to post a screenshot of your geometry in Ansys Design modeler

May 29, 2016, 17:26		#3
h.alavi1990 New Member Hossein Join Date: May 2016 Posts: 3 Rep Power: 9	Hello, I'm trying to mesh a radial turbine (with splitters) Using TurboGrid, I have exported the geometry of blades and splitters using Design Modeler via two separate ExportPoints features for blades and splitters. Here is where I'm stuck: 1. When I try to mesh the turbine with both blades and splitters, I get the same topology error which is discussed in this topic. 2. I can mesh a turbine with just blades, or just splitters which seems to mean that the curves don't have any problems and topology constraints is the cause of error. 3. I changed the the place of leading edge and trailing edge and meshed the geometry as a centrifugal compressor, this resulted to a nice mesh without even a warning! Is it possible that I use the compressor mesh and correct it by boundary conditions in the next step? Would this effect the validity of results?

March 4, 2020, 08:59		#4
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Hey all, Any resolution to this? Im trying to add a second splitter to a compressor model and that seems to be triggering the error the first poster described/.