[Q] Boundary conditions in Turbomachinery

ghlee

Dear friends ! I'm calculating centrifugal compressor in steady state. Unshrouded impeller & vainless diffuser is used. Pressure ratio is nearly 1.0, thus incompressible flow assumption is made. I used rotating coordinate system, relative velocity components, standard k-epsilon turbulence model. In this situation, addtional force terms(Coriolis force & Centrifugal force) is included in source term. In general, boundary conditon for turbomachinery has four types. (1) Inflow (2) Outflow (3) Wall (4) Periodic My questions are below. (1) We put upstream & downstream region from impeller in order to give boundary conditions easily. These regions are stationary (i.e. not rotating), thus can I omit additional force term due to rotation? (2) Because the coordinate system is fixed to impeller, shroud casing is rotating in oppose direction, and it has circumferential velocity. We treat the shroud casing as wall in using wall function. In this case, is there anything to change in wall function? Though many questions are remain, I would end question. Thank for your reading...