Influence of the inclined leading edge diffuser vanes on the aerodynamic performance of a transonic centrifugal compressor

Abstract

Three-dimensional, compressible, Reynolds-averaged Navier-Stokes equations were solved to investigate the influence of the inclined leading edge diffuser vanes on the flow field and performance of a transonic centrifugal compressor with a high compression ratio. Diffuser vanes with leading edge inclined at different angles (10 different cases) were numerically modeled to investigate the effects that the inclined leading edge of the diffuser vane had on the diffuser pressure recovery and total pressure loss characteristics of the compressor. Diffuser vanes with an inclined leading edge reduce the interaction between the impeller discharge flow and the leading edge of the diffuser, which results in a reduced separation inside the diffuser passages. A maximum diffuser pressure recovery coefficient of 0.7185, was observed at a 30-degree inclination angle from hub-to-shroud. Moreover, in the case of inclination angles greater than 60 degrees for both hub-to-shroud and shroud-to-hub, there is a significant reduction in the pressure recovery, efficiency and pressure ratio.