A Numerical Study of Volute Design in Centrifugal Compressor

Abstract

Our principle goal of this study is to develop a CFD based analysis procedure that could be used to analyze the geometric tradeoffs in scroll geometry when space is limited. In the study, a full centrifugal compressor stage at four different operating points from near surge to near choke is analyzed using Computational Fluid Dynamics (CFD) and laboratory measurement. The study concentrates on scroll performance and its interaction with a vaneless diffuser and impeller. The numerical results show good agreement with test data in scroll circumferential pressure distribution at different ΛAR, total pressure loss coefficient, and pressure distortion at the tongue. The CFD analysis also predicts a reasonable choke point of the stage. The numerical results provide overall flow field in the scroll and diffuser at different operating points. From examining the flow fields, one can have a much better understanding of rather complicated flow behavior such as jet-wake mixing, and choke. One can examine total pressure loss in detail to provide crucial direction for scroll design improvement in areas such as volute tongue, volute cross-section geometry and exit conical diffuser.