Effects of Shroud Curvature on the Performance of Centrifugal Compressor Blade

Abstract

The purpose of the study described in this paper was to investigate the impact of shroud curvature on the performance of a centrifugal impeller or stage. The paper discusses a computational fluid dynamics (CFD) study done to assess the influence of shroud curvature on impeller performance. The computational fluid dynamics (CFD) and finite element analyses (FEA) methods were used to describe the various designs of the impeller. Aerodynamic and mechanical analysis results are presented for four impellers of varying cover curvature and axial length. The aerodynamic results showed there were clear aerodynamic benefits to decreasing the curvature along the impeller shroud. The mechanical analytical results showed that the impeller with the lowest curvature or longest axial length provided the highest performance; it also yielded the lowest Von Mises stress level. In closing, there are clear aerodynamic benefits to decreasing the curvature along the impeller shroud but these benefits must be weighed against the impact on the rotordynamic considerations Comments are offered regarding the rotordynamic issues that must be considered when increasing the length of impellers.