Surge Inception Point Analysis Using the Greitzer Model for Centrifugal Compressor

Abstract For modern centrifugal compressors, the widest operating range is desired. At a low mass flowrate, the operating range is limited by the surge phenomenon described by the Greitzer model. It is widely believed that the surge inception takes place directly at the maximum point of the compressor performance curve. In this study, we are showing the exact surge inception point that can be located behind the curve maximum. The key parameter in the Greitzer model is named B and it should be unique for a given compressor and plenum. According to Greitzer, there is a critical value of B (named Bcr herein) that represents a threshold between stable and unstable system operation. In this study, Bcr is analyzed and determined pointwise along the unstable part of the compressor performance curve. We have found that Bcr is changing with the mass flowrate. This allowed us to find the unique surge inception point for a given model with a known B and compressor performance map. It was also shown that for each compressor performance curve, there exists a limiting Bcr0 value that provides ultimate stability for the system, even at the left-hand side of the performance curve widely considered as unstable. The determined values showed good agreement with selected articles where the surge inception point and the B value of the system were provided. The formula for surge point inception was determined to provide a practical application of the presented theory.