Numerical study of flow field of volute in a turbocharger centrifugal compressor

To understand the influence of volute on centrifugal compressor performance of turbocharger and the flow field inside the volute, a high-speed and low-mass flow rate centrifugal compressor with two different volute tongue shapes was simulated by 3D viscous Navier-Stokes equations. The flow fields in the vicinity of volute tongues and inside the volutes, the velocity and pressure distributions of streamwise and volute characterized cross-sections were analyzed. Results show that tongue modification has apparent effectiveness on of pressure raising and efficiency improvement. Mass flow rate has influence on flow incidence to the volute tongue. There has certain incidence angle at large mass flow rate and no incidence angle at low mass flow rate. Recirculation flow to volute increases as mass flow rate decreases. Low pressure region, locating from 60° to 120°circumferentially, appears at diffuser inlet under the designed condition and the location of minimum static pressure varies under low mass flow. In volute, the flow velocity is high at inner radius on cross-sections where the pressure recovery coefficient is low. Higher pressure loss at volute passage geometry center is presented with closing to the volute outlet.