# problems with compressible flow in turbine

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 June 12, 2003, 15:02 problems with compressible flow in turbine #1 Birute Guest   Posts: n/a Hello everybody, I am modelling two-stage steam turbine. I am using pressure boundaries for inlet and outlet, k-e high Reynolds number turbulence model, implicit multiple rotating reference frame and static enthalpy (for temperature calculations). Inlet conditions: static pressure 4.66E+4 Pa(relative) and temperature 323K, outlet conditions: -1900 Pa (relative) and temperature 292.8K. Flow is compressible (Ideal-f(T,P)), for molecular viscosity: Sutherland correlation. I am using MARS differencing scheme with blending factor 0.5 The main problems is with temperature, velocities and turbulent kinetic energy in the last frame (2-nd stage rotor part). The temperature drops down and value at the outlet is about 274K, which not correspond with boundary value at all. The velocities are much higher. The turbulent kinetic energy values are also very high at this part. The pressure values are very OK. I could be very thankful for any suggestion, why it happens like this. What I am doing wrong? Please, help me!!! Best regards, Birute

 June 12, 2003, 23:43 Re: problems with compressible flow in turbine #2 CJ Tune Guest   Posts: n/a I think you should use 'total enthalpy' conservation for compressible flow temperature calculation.

 June 13, 2003, 08:22 Re: problems with compressible flow in turbine #3 Birute Guest   Posts: n/a Thanks for suggestion, but I already tried to use total enthalphy option, but it doesn't work. The total enthalphy in whole domain is the same. Regards! Birute

 June 13, 2003, 09:10 Re: problems with compressible flow in turbine #4 Joern Beilke Guest   Posts: n/a It is a bug in version 315 with the pressure work term. You have to set "rcon 146 1"

 June 14, 2003, 09:59 Re: problems with compressible flow in turbine #5 CJ Tune Guest   Posts: n/a Does this apply to all cases or just for compressible flow?

 June 14, 2003, 15:34 Re: problems with compressible flow in turbine #6 Joern Beilke Guest   Posts: n/a It seems to apply for rotating frames calculations only. Sliding mesh works without the rcon. Since the temperature is not a function of the pressure for incompressible flows I would guess that it can not be very important there. So you can either try it or ask the support.

 June 20, 2003, 04:32 Re: problems with compressible flow in turbine #7 Jing Guest   Posts: n/a I have done the similar calculation and have the similar problem. For me it is caused by the Enthalphy definition. So, please have a look if you really define the Total Enthalphy as a constant in your calculation. An other possibility is if you define the rotating velocity in a right direction, and, for the rotor and stator seperately.

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