recirculations at inlet/outlet cavity

Abe

Hello,

My question is about unsettled/unrealistic recirculations at the inlet and outlet cavities.

I am modeling a cavity between rotor and stator. In the entire cavity, there are some flow obstructions attached to stator like labyrinth teeth. I defined high/low static pressure at inlet and outlet boundaries. Rotor surface is rotating at an rpm. I like to calculate mass flow rate as function of pressure drop.

I used k-epsilon approach. I turned on "density ideal-f(T,P)" for compressible flow. I tried many options to have a nice streamlined flow at inlet/outlet cavities. It looks like rotor speed in the tangential direction causing the recirculation problem. I defined a linear tangential velocity which is maximum over rotor and zero at stator. I tried zero gradients on pressure boundaries. I extended/shortened the inlet/outlet cavities to get a developed flow conditions. However none of the tries have worked so far.

Any ideas to resolve the problem would be appreciated.

Thank you in advance for any help. Abe.