Hydrodynamic cavitation is widely used in industrial fields such as sterilization,emulsion preparation,and efficient hydrodynamic cavitation reactor is the basis for realizing its application.Taking a centrifugal self-excited hydrodynamic cavitation reactor as the research object,based on Realizable κ-ε turbulence model and Zwart-Gerber-Belamri cavitation model,numerical simulations of the cavitation flow field and sound field characteristics of three-dimensional transient unsteady flow were performed in the reactor under design conditions,the cavitation development state at different liquid level heights was analyzed,and the cavitation noise pulsation and development at different positions of the reactor were studied.The results show that the cavitation characteristics of rotor with different liquid levels are obviously different.With the rise of liquid level,the cavitation area continues to increase,but the cavitation development space is too large in the later stage of liquid level rise,and the overall cavitation intensity cannot match the development space.The strong cavitation area increases first and then decreases,reaching the maximum when the liquid level is between 3~4 mm,and the weak cavitation area continues to grow.Cavitation is an important factor affecting the blade frequency and its multi-order harmonic noise of the reactor.Along the flow direction,the sound pressure amplitude of the blade frequency in the reactor increases with the development of cavitation,showing a periodic change from increase to stability to decrease.