The Development, Application and Experimental Evaluation of a Design Procedure for Centrifugal Compressors

Abstract

A computer-based centrifugal compressor design procedure developed at the National Gas Turbine Establishment is described. The impeller design package includes a geometry modelling procedure, aerodynamic analysis, stress analysis, and the direct generation of data for manufacture by numerical control. The method of diffuser design incorporates analyses of the flow in the vaneless space and ‘semi-vaneless’ space adapted from a new performance prediction technique; published diffuser pressure recovery data are used in the selection of the diffuser channel geometry. The application of these methods to the design of a 6.5 pressure ratio centrifugal compressor stage is described. The experimental rig testing of this compressor has been used to evaluate the advantages offered by the new design procedure. By comparing the measured performance with that of an earlier compressor designed with less advanced techniques for the same aerodynamic duty, the advantages of the new design procedure are established.