Numerical investigation of the flow in a centrifugal compressor intermediate stage

Numerical simulation is applied to investigate the flow in the intermediate stage of a multistage centrifugal compressor. The effects of the inducer, bend duct and return channel on the performance of the stage are intensively investigated. The results show that the losses in the bend duct and the return channel is much smaller than that in the inlet part, and that the disturbance of the flow from the deswirl exit reduces the surge flow rate of the intermediate stage. Besides, the influences of the outlet setting angle of the deswirl blades to the stage efficiency and pressure ratio are explored.