Analysis of internal leakage flow field and cavitation noise in a hydraulic poppet valve
The detection of internal leakage in hydraulic poppet valves poses significant challenges.When there is a leakage in the hydraulic poppet valve,the pressure and velocity gradient of the fluid in the valve will change drastically,causing severe cavitation and cavitation noise.The characteristics of the noise are seen as a crucial metric for assessing internal leakage in poppet valves.Studying the noise characteristics is of great significance to the acoustic detection and evaluation of internal leakage of poppet valves.Through building a numerical analysis model for internal leakage in poppet valves,we adopt the Realizable k-ε turbulence model,the Schnerr-Sauer cavitation model,and the broadband noise model to analyze the cavitation and induced noise of the flow field in the poppet valve under different leakage gaps and different pressure conditions and explore the influence of the leakage gap and pressure conditions on cavitation noise.Our results show a high-speed jet is formed at the valve port leakage.As the inlet pressure increases,the cavitation area gradually expands,and the maximum sound power level of the internal leakage sound field rises accordingly under the same leakage gap.The high noisy area of the sound field gradually moves towards the tail of the valve.Under the same inlet pressure,as the leakage gap grows,the cavitation area gradually becomes smaller and the maximum sound power level of the internal leakage sound field first increases and then decreases.When the leakage gap reaches 0.4mm,as the inlet pressure goes up,free cavitation occurs at the valve tail.Our results reveal the changing trend of cavitation noise during internal leakage in poppet valves under different operation conditions,providing theoretical support for leakage detection in hydraulic poppet valves.
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