Perspectives of Phase-Portraits in the Detection of Compressor Instabilities-Inception of Stall

Abstract : The operative range of axial-flow compressors is limnite by the onset of instabilities, namely rotating stall and surge that arise when the mass flow is reduced at constant rotational speed. The difficulties in correctly predicting the point of stall onset have made it necessary to establish a limit line on the performance map that cuts out operative points of high efficiencies. The particular behavior of this non-linear complex-but-structured phenomenon has suggested a scientific approach with the tools of Chaos theory. The result given by the Phase-Space reconstruction from experimental time series has suggested the possibility of applying this technique, not only to characterize the system's dynamics, but also for monitoring purposes. The experiments have been planned to capture the transition from clean flow to stalled conditions. The Phase-Portrait of the different types of stall is presented. The results from the different sensors are compared and an indicator for stall inception detection presented.