Numerical Simulation Of Cavitation Flow In Hydraulic Poppet Valve

Poppet valves are widely used in hydraulic components because of their simple structure,simple technology and good sealing performance.The flow field at the valve port of cone valves has the characteristics of high flow velocity and large pressure difference,which easily induces cavitation flow and causes vibration and noise of components or systems.With the development of hydraulic technology towards high pressure,high speed and high power,the research on cavitation in hydraulic components has been paid more and more attention.In this paper,hydraulic cone valve is taken as the research object,and the mechanism,flow pattern and control method of cavitation at the valve port of the cone valve are deeply studied by combining theoretical analysis with numerical simulation.The main contents of the thesis include:The first chapter summarizes the background and significance of this research,and expounds the present situation of the research on the cavitation of the valve opening of hydraulic cone valves at home and abroadThe second chapter describes the mathematical model used in this project,and carries out the model validation and grid independence test.In the third chapter,study on cavitation flow characteristics of cone valve orifice before and after turbulent viscosity correction.Before and after cavitation,the mixing density of medium varies greatly.Considering the correction of turbulent viscosity,the period of vapor volume fraction becomes longer,the maximum value decreases,and the axial fluid flow force of the whole cone surface of the va lve core decreases.The downstream axial fluid flow force of the valve core is the main factor affecting the axial fluid flow force of the whole cone surface of the valve core.In the fourth chapter,the influence of back pressure on the cavitation flow characteristics of hydraulic cone valve orifice.With the increase of back pressure,the period and amplitude of vapor volume fraction decrease,the axial fluid flow force of the valve core increases,the pulsation decreases,and the flow field tends to be m ore stable.In the fifth chapter,the influence of the frequency and amplitude of the velocity fluctuation at the sinusoidal inlet on the cavitation flow characteristics of the cone valve orifice is discussed.Finally,the paper summarizes the content of t he article,and prospects the shortcomings and future research.With the increase of inlet velocity fluctuation frequency,the phase lag of vapor volume fraction increases,and the axial hydraulic force of the valve core increases.With the increase of inl et velocity fluctuation amplitude,the maximum vapor volume fraction increases,and the axial hydraulic force of the valve core increases.