Model test study on cavitation noise and vibration characteristics of fixed-cone valve for ecological energy dissipation in hydropower station

In order to study the cavitation noise and vibration characteristics of fixed-cone valves, the pressure, noise and vibration of fixed-cone valves under different opening and cavitation operation conditions were measured and analysed in the paper. The total sound pressure level of cavitation noise increases significantly with the development of cavitation and the distribution of the sound pressure level in each frequency band changes significantly from the turbulence to the choking cavitation stage. The noise is low frequencies in the turbulent stage and the high-frequency noise is significantly enhanced after cavitation. The flow of fixed-cone valve is firstly divided into four stages in this papers according to noise: turbulence, incipient cavitation, constant cavitation and choking cavitation. There is widen and various spectral peaks in constant and choking cavitation stages. The vibration signal analysis shows that the vibration spectra of different cavitation stages gets broaden and intensify with the increase of cavitation intensity, especially in the frequency band above 1 kHz. The noise and vibration characteristics show significant differences in different openings and cavitation states. It is first exploring to determine cavitation critical points and 4 flow stages with noise characteristics in this paper. The research will provide experimental basis and theoretical support for optimizing the valve structure and improving the anti-cavitation capability.