I am trying to analyze air compressor in fluent need help in BC's
 

I am trying to analyze air compressor in fluent
I have a geometry created in solidworks for air compressor with inlet casing fins and outlet and inside compressor blades.

I am trying to do cfd analysis using fluent.
What boundary conditions should i try?
I tries pressure inlet and pressure outlet but the model diverges
even tries mass flow inlet and pressure outlet then x-momentum diverges.

Which model I should use i used LES solver and Spalart-Almaras solver. but got divergence in both models

Can anybody help me out with this?

Thanks