High-Speed Centrifugal Compressor Surge Initiation Characterization

An experimental study is performed to characterize the behavior of a high-speed centrifugal compressor as it approaches instability. To achieve this, data at the inlet and exit of the centrifugal compressor are analyzed. Three inducer bleed conditions are examined. Data analysis indicates that the disturbance was a 9-lobed stall pattern occurring in or near the diffuser and suggests that the phenomena is different than that typically referred to as impeller stall. The component pressure characteristics show a reduction in diffuser performance corresponding to the rise in the spatial mode magnitude, with minimal effect on the impeller. It is suggested that the rotating stall condition that was observed in this compressor may play a similar role to that observed when rotating stall initiates surge in multistage axial compressor.