Modeling engine effects
My question is about modeling the effect of a gas turbine on the flow through an intake duct.
I have an intake duct, turbine and exhaust duct in a standard configuration: Intake Duct volume > Boundary Condition Face > Turbine Volume (empty, not meshed) > Boundary Condition Face > Exhaust Duct volume What B.C should I use at the end of the Intake duct volume  I know the massflow that the turbine requires, but not the Static Pressure or Total Pressure at this face. What B.C for the inlet face of the Exhaust Duct? Thanks Riaan 
Re: Modeling engine effects
Do you want to MODEL the turbine, not actually calculate it (I mean you do not want to insert real turbine geometry in the middle volume and take its effects into account by simply imposing BC on the two faces)?
Razvan 
Re: Modeling engine effects
No, I don't want to model the turbine, just have a "black box" with inlet and exit b.c. similar to what a turbine would generate.

Re: Modeling engine effects
Let me explain myself:
 MODELING = taking into account the possible effects of a certain geometry by analitical means, approximating it with a mathematical model, actually deliberately imposing not calculating its properties;  SIMULATING = considering real geometry, calculating effects by imposing conditions on boundaries away from actual object. So, what you're trying to do is MODEL the turbine, not SIMULATE it! Concerning your problem, the only way I can imagine solving it is this:  eliminate first and second volume and keep only exhaust pipe with turbine exit as inlet condition  calculate by hand or using a mathematical program the radial distribution of fluid's thermodynamic properties based on specific turbomachinery relations  input these radial profiles as BC at the inlet boundary  obtain solution. Of course, you will have to repeat steps 24 for every mass flow you need to consider. Best wishes, Razvan 
Re: Modeling engine effects
Found easier way. Set Massflow inlet B.C. at the turbine inlet face, with the massflow vector pointing "into" the turbine. Since this is a subsonic case, pressure values on the b.c. face will be interpolated from the cells next to the b.c.
Anycase, agree on difference between modeling and simulating. Quick and dirty forum post  sorry. 
Re: Modeling engine effects
Running into problems  seems the Massflow inlet creates a local strong shock in the exit plane...M>2...don't know why yet?

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