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dmaz February 20, 2013 05:40

Steam turbine, Non equilibrium case
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Hi, I'm quite a novice in the use of Fluidodynamic software’s. I have to simulate the stream flow between the blades in a steam turbine.
I'm trying to adapt the non-Equilibrium case, as explained in the Chapter 26 of the CFX tutorials, to my CFX model(an extruded 2D model of a turbine blade).
My boundary conditions are:
Total inlet temperature: 354 K
Total inlet pressure: 0.403 bar
Static outlet temperature: 0.0662 bar

I'm using a Physical timescale of 0.0005, k-Epsilon model, a quite regular mesh.

A message appears during the setting of the CFX model:
"In Analysis 'Flow Analysis 1' - Domain 'Default Domain': This compressible multiphase simulation has a single continuous phase and uses a total pressure boundary condition. The dispersed phases will not be included in the total pressure (frozen total pressure assumption)."
What does it mean? I noticed that if I use the velocity inlet instead of the total pressure inlet, the simulation works, but I must use the Total Pressure for my simulation.
The simulation works for almost 30 Time steps, then it crashes. Suddenly the RMS P-Vol decrease and the Volume fraction of the liquid phase and the turbulence parameters have a great increase (you can see it in the attached image).
How can I fix this simulation? Where I'm doing wrong?
Thanks to everybody who will answer me!

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