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2 stage axial turbine model convergence issues |
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September 7, 2009, 12:40 |
2 stage axial turbine model convergence issues
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#1 |
Member
Sherif Kadry
Join Date: May 2009
Posts: 38
Rep Power: 17 |
Hello,
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. Model specifics: -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 Sherif |
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September 7, 2009, 14:15 |
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#2 |
Senior Member
George
Join Date: Mar 2009
Location: Birmingham, UK
Posts: 257
Rep Power: 18 |
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
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September 7, 2009, 21:51 |
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#3 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,862
Rep Power: 144 |
Here's the link George referred to: http://www.cfd-online.com/Wiki/Ansys...gence_criteria
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