Mixed-flow pump cavitation characteristics extraction based on power spectrum density through pressure pulsation signal analysis

Mixed-flow pump is an important machine for transporting fluids, which has the advantages of both centrifugal pump and axial flow pump, but it is prone to cavitation, endangering efficiency and safe operation. A 20 m × 8.5 m high-precision hydraulic mechanical stand and a vertical mixed-flow pumping station device were built for the study of cavitation signals. The detection of pressure pulsation signal is a direct measurement of the cavitation region, and the decay of information is less. In this study, the time domain and frequency domain characteristics of water pressure pulsation signal are analyzed by using fast Fourier transform method. The power spectrum density (PSD) is used to extract the characteristics of each cavitation stage, especially the full cavitation stage with random signal characteristics. The results show that PSD method reflects more information and is more sensitive than traditional time–frequency domain analysis. The characteristic power spectrum (PS) value of the cavitation of the mixed-flow pump machinery can be given through the feature extraction of the PS, which plays a great role in the effective identification and prevention of cavitation.