Evaluation of Aerodynamic Instability Mechanisms for Centrifugal Compressors—Part I: Current Theory

Abstract

Current theories of calculating levels of aerodynamic excitation are reviewed and methods of applying these results to actual compressor designs are discussed in detail. Comparison of compressor stability for approximate modal aerodynamic excitation influence to published equations for static labyrinth seal cross-coupled stiffness is made to illustrate the influence of system damping on compressor stability. The results of analysis for six operating machines are presented to give further justification for the selection of the aerodynamic excitation model.