|September 7, 2009, 11:40||
2 stage axial turbine model convergence issues
Join Date: May 2009
Posts: 38Rep Power: 9
I was hoping any CFX turbo gurus could give me some guidance on achieving a converged model of a axial turbine. The model uses a straight stator and bowed rotor blades. I have actual experimental data to use for my boundary conditions. The rotor stage mesh was obtained from a colleague and had performed fairly well in a previous model (previous models had bowed stator and rotor blades). I needed to create a straight stator blade mesh which I did using ICEMCFD.
-2-stage model (stator and rotor geometry are the same for each stage)
-steady state model
-stage interface was used the pitch to pitch ratio is 1.0 equal blade numbers for stator and rotor.
-total pressure inlet bc specified (based on experimental data).
-exit static pressure bc specified (based on experimental data).
-SST model was used as recommended by ANSYS
The main problem is the model does not converge, I have investigated the stator mesh and it seems to be okay (refining or coarsening of the mesh seems to still produce a diverging model) that could also be a problem point not really sure as I am mainly an experimentalist. Could this be an issue with the stage interface definition and aligning the stator exit and rotor inlet? Any tips or advice would be much appreciated
|September 7, 2009, 13:15||
Join Date: Mar 2009
Location: Birmingham, UK
Posts: 257Rep Power: 10
not a turbo expert but check the faq for convergence problems
my guess (if you checked everything else is fine) is that your problem is not steady state
Top 4 tips
1. Knowledge is everything and Ignorance is dangerous.
2. Understand your limitations and try to eliminate them.
3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window.
4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials
|September 7, 2009, 20:51||
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 12,709Rep Power: 98
Here's the link George referred to: http://www.cfd-online.com/Wiki/Ansys...gence_criteria
|cfx turbo divergence|
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