Refiner Error 255
 

Hello All,

I try to model CH4 combustion and I'd like to make mesh adaption in the reaction region. Hence, I set up CH4.Mass Fraction as adaption criteria in CFX12 Pre. Mesh Adaption was started every 10 iterations.
While solver was running, Refiner has started and terminated with the message:

"An error has occurred in cfx5solve:

The ANSYS CFX mesh refiner could not be started, or exited with return code 255:"

Before that one I've recived a windows send report message about refiner.

What does code 255 means?
When it usually appears?

Regards, A.m.

what i can tell you is, last time I encountered this error code is because of large aspect ratio which exceeded the limit.

Hope this would help..

Thanks zxin,

I've solved this problem by mesh changing. First time I used ANSYS Meshing to generate mesh. I checked its quality in ICEM CFD and received following results: min = 0.013, max = 23.05, mean = 1.87 (aspect ratio).
Then I generated ICEM CFD mesh and checked it. I received following:
min = 0.25, max = 0.99, mean = 0.75 (aspect ratio). Also I decreased a numer of elements by a factor of 1.8 and removed prism layers (inflantion).
With the new mesh remesher works perfectly.:)

P.S.
old mesh http://upload.akusherstvo.ru/thumbs/256436.jpg

new mesh http://upload.akusherstvo.ru/thumbs/256438.jpg

That's great...
but sometimes, my mesh with aspect ratio close to 1000 generated by Ansys Mesh, works fine with CFX, CFX is quite stable solver, i think...:o

But with no prism layers your boundary layer modelling will be hopeless. You clearly have a mesh quality problem, but you need to generate a high quality mesh with prism layers.

I' m modeling the CH4 combustion process, therefore finer stoichiometric region is more important for me then boundary layer.

Isn't the heat transfer important? Won't that set the heat lost to the walls, and be a major contributor to combustion temperature? You will need a good prism layer mesh to resolve that.

Thanks ghorrocks,

Sure it is very important too and I'm working on it:) By the way, how many prism layers I need to resolve the wall heat transfer?

That's problem dependent. The discussion in the CFX documentation on near-wall modelling is a good starting point, but you then need to do a sensitivity study to find out what your specific case requires.

Thanks a lot!

Error Code 255
 

I do not know what Error code 255 means. Im not an expert at Ansys or CFD. But I do know that it has been solved, every single time, by deleting my mesh and remeshing with new settings. I am not saying you should do this. If you are truly desperate you may give it a try.

Error 255
 

What kind of meshing is advisable to solve the ERROR code 255 ???

I am using ICEM CFD to mesh my geometry. Am ugetting the following error
"The ANSYS CFX solver could not be started, or exited with return |
| code 255: . No results file has been created."

Now am using the following:

Mesh type on surface: All Tri
Mesh type in volume: Tetra/Mixed
surface Mesh method: Patch Independent
volume Mesh method: Robust (octree)

Thank you very much