Preliminary Staging Selection for Gas Turbine Driven Centrifugal Gas Compressors

A procedure for optimizing the preliminary design of a gas turbine driven multistage centrifugal compressor package is discussed. The optimization procedure is based on the variation of single-stage centrifugal compressor adiabatic efficiency as a function of specific speed and Mach number. It permits the selection of optimum impeller diameter and the number of stages to cover a prescribed compressor market zone, indicating regions of maximum efficiency. Flow limitations resulting from decreasing efficiency at off-optimum specific speeds, as well as the mechanical design limitations following excessive seal temperatures and axial thrust, are delineated. The procedure has been successfully used at the author’s company for the preliminary selection of stage geometries for a family of multistage gas compressors.