Numerical Optimization of a Vaned Shroud Design for Increased Operability Margin in Modern Centrifugal Compressors

Abstract

This paper describes the computational fluid dynamics (CFD) approach coupled with an automated grid generation technique utilized for the numerical optimization of a modern centrifugal compressor with an inducer vaned shroud for increased operability margin. The grid generation process was automated to permit rapid optimization of the impeller and vaned shroud geometry. A three-dimensional, viscous, steady flow, mixing-plane approach was utilized to numerically analyze the impeller and vaned shroud in a coupled fashion to capture the interaction effects. The numerical technique verifies the ability of the vane shroud to extend compressor surge margin at the part-speed operating condition, while maintaining acceptable high-speed performance. CFD analyses confirm that the aerodynamics of the vaned shroud match expectation, and are consistent with the mass-averaged compressor speedline characteristics generated from the CFD results.