Rotating stall performance and recoverability of a high-speed 10-stage axial-flow compressor

Design factors which influence rotating stall recoverability of a high-speed multistage compressor are not yet fully understood. A high-speed, 10-stage compressor component was tested while operating in-stall to investigate parameters that affect the overall recoverability of a multistage compressor. The compressor instrumentation and data acquisition procedures were designed to obtain detailed performance data from the compressor while it entered into a rotating stall condition and while it operated in rotating stall. The compressor was tested at different in-stall operating conditions by varying compressor shaft speed, discharge throttle, and variable geometry settings to determine the effect of each variable on rotating-stall performance and recoverability. Test results suggest that the stall cell may not extend the full length of the compressor but instead can be confined to a portion (here the rear stages) of the compressor. When stages are stacked together, as is the case in a multistage compressor, the stalled performance and subsequent recoverability are greatly affected by how well the stages of the compressor are matched. The results also suggest that high-speed flows in the tenth stage may extend in-stall operation causing low recoverability of the overall test compressor at higher shaft speeds.