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-   -   boundary conditions turbine (http://www.cfd-online.com/Forums/openfoam/97692-boundary-conditions-turbine.html)

riesotto February 22, 2012 16:05

boundary conditions turbine
 
Hi All,

I want to simulate the flow in a turbine with the rhoPorousMRFSimpleFoam.

Until now I have simulate the flow in a centrifugal compressor . Therefor I have done some experimental studies with the compressor. I have measured the flow rate for different rotation speed (rpm). Then I used this data for my boundary conditions:

- for the velocity U
inlet: fixed value for U (from the measured data)
outlet: zeroGradient

- for p
inlet: zeroGradient
outlet: fixed value (measured data)

The simulation works and I get a convergent case (not sure the results are right, but they look reasonable).
...

Now I want to simulate the compressor as a turbine. In this case, the fluid flows from the "outlet" into the compressor and exits the compressor from the "inlet".
For my first simulation of the turbine I used the experimental data of the compressor and reverse the direction of rotation. Additionally I change the inlet and the outlet.
But I get bad convergence and very high velocity at the rotor. The results looks very unreasonable. I am a little bit confused.
What are the right boundary conditions for simulate a turbine with rhoPorousMRFSimpleFoam ?????
Is there a real difference between a simulation of a turbine and a compressor???


Please help
Kind regards
Florian


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