Study on Noise Characteristics of Marine Centrifugal Pump Under Different Cavitation Stages

Based on judging the different stages of cavitation through high-speed photography experiments, this paper presents a strategy for analyzing the variation in noise under different cavitation stages using the BEM method and Proudman theory. A multi-field synchronous test bench for marine pump hydraulic performance, flow noise, cavitation performance and cavity distribution is built. The critical cavitation numbers in different cavitation stages were determined by combining the cavitation performance curve and the morphology of the cavitation in high-speed photography. The research shows that with the development of cavitation, the rotor–stator interaction-induced noise is no longer the main noise source. The bubble will gradually block the flow passage and play a role in absorbing sound to reduce the area of the high sound power region. The sound pressure level of the blade passing frequency and its harmonic frequency gradually decreases. Under the action of the fan sound source, the drop in the 2BPF is the most obvious, and the maximum drop is 10%. The sound pressure level at the shaft frequency and the broadband total sound pressure level above 1000 Hz gradually increase, reach the maximum value under the developed cavitation stage. Cavitation-induced noise is broadband noise and its energy is concentrated in high frequencies.