Development of a high specific speed centrifugal compressor

Abstract

This paper describes the development of a subscale single stage centrifugal compressor with a dimensionless specific speed (Ns) of 1.8, originally designed for full size application as a high volume flow, low pressure ratio, gas booster compressor. The spedfic stage is noteworthy in that it provides a benchmark representing the performance potential of very high specific speed compressors of which limited information is found in open literature. Stage & component test performance characteristics are presented together with traverse results at the Impeller exit. Traverse test results were compared with recent CFD computational predictions , for a exploratory analytical calibration of a very high specific speed impeller geometry. The tested sabscale (0.583) compressor essentially satisfied design performance expectations with an overall stage efficiency of 74% including, excessive exit casing losses. It was estimated that stage efficiency could be increased to 81% with exit casing losses halved.