Experimental Study on Cavitation Noise Characteristics of a Hydraulic Model of Mixed-Flow Pump

In order to investigate the characteristics of the cavitation noise of the hydraulic model of a mixed-flow pump, the noise variation law at the inlet and outlet four times the pipe diameter under different operating conditions of each effective cavitation margin was studied through experiments, and the noise variation law of the hydraulic model of mixed-flow pump without cavitation and in the process of cavitation was compared. The study analyzed and examined the noise frequency domain variation of the cavitation process. The findings indicate that the noise changes in the inlet and outlet of the cavitation process are noticeable and follow a certain pattern. Specifically, the total noise pressure level at the inlet tends to increase initially as the cavitation margin decreases. However, it gradually decreases after reaching the extreme value. while the peak value at the leaf frequency and its harmonic frequency gradually disappear, and the noise decreases significantly. When the head decreases by 1%, the cavitation enters the complete stage, and the noise pressure level in the low-frequency band increases significantly, while in the high-frequency band, the noise pressure level is significantly smaller than in the unactivated state.