Experiments With a Low-Specific-Speed Partial Emission Centrifugal Compressor

Abstract

This paper describes experiments that were conducted several years ago on a single-stage open-face centrifugal partial emission compressor with a nondimensional specific speed of 0.15 (19.3 dimensional). The purpose of the experiments was experimentally to evaluate the partial emission compressor as a possible candidate for a high-speed low-flow natural gas fuel pump, the alternative to which was a larger heavier reciprocating compressor. A review and re-analysis of the test data were conducted. They used updated compressor data reduction performance procedures and flow models to redefine the experimental compressor as a reference case in the low-specific-speed range of single-stage centrifugal compressors. Normalized performance characteristics are presented for the experimental compressor in terms of efficiencies, diffuser recovery, and head coefficients versus diffuser relative flow parameter, or choke margin. Peak efficiency, obtained at a De Laval number of 1.16, and nondimensional specific speed of 0.15, was 34.5 percent. Stage performance is found to be dominated by diffuser geometry and choke margin, plus windage losses.