MONITORING OF AERODYNAMIC LOAD AND DETECTION OF STALL IN MULTISTAGE AXIAL COMPRESSORS

The unsteady flow in a single-stage axial flow compressor at different operating conditions has been investigated with hot-wire and hot-film probes to find out the influence of the aerodynamic compressor load o n the periodic fluctuations. These results are compared with measureme nts in the last stages of a multistage high-pressure compressor of a g as turbine for normal operation and under stall conditions. From the p atterns of the frequency spectra of the measuring signals a parameter for the detection of the approach to the stability line of a compresso r is derived. A method for the on-line monitoring of the aerodynamic l oad is presented. Based on these results a monitoring system has been developed. First experiences with this system, applied to two multista ge compressors, are reported.