Spectral analysis of pump-cavitation noise

Pressure-transducer and accelerometer data accumulated during several water tests of a liquid-rocketengine pump were subjected to spectral analysis. The analyzer used allows signal amplitude to be displayed as a continuous function of frequency for each instant of time. Various filter bandwidths, integration times, frequency spans and display formats have been used to present the data for visual inspection. Results of attempts to discern the signature of various phases of the cavitation phenomenon occurring within the pump are reported.