The Cavitation Mechanism And Simulation Research Of Axial Piston Pump

The axial piston pump is widely used in hydraulic systems as power unit, which plays animportant role in the engineering machinery. In its working process, the pressure field and andflow state is complicated and uncertain, which makes cavitation more likely to occur; and thevibration and noise caused by cavitation will affect the performance and stability of the wholesystem, or even leading to the pump failure. So we need to study the cavitation mechanismand its mathematical model within the axial piston pump in order to avoid or reduce theoccurrence of cavitation, and to improve the performance and stability of the pump.The mathematical model of cavitation in the axial piston pump is established. The gasdissolved in the fluid will be released if the pressure in the pump chamber is lower than the airseparation pressure, thus the fluid is a homogeneous mixture of oil and air. And there will bephase change in the liquid when the liquid pressure is reduced to its saturated vapor pressure.And the fluid will be a homogeneous mixture of oil, oil vapor and air, which is totallydifferent from the cavitation mechanism of conventional water conservancy machinery.Therefore, the bubbles in the fluid were taken as the object of this study, considering the fluidmechanics and all of the calculated fluid properties, including the pressure change, massflow and volumetric void fractions of vapour and air, a modified Rayleigh-Plesset equationfor the control volume accounting for the bubble interaction is obtained. To analyze the law ofliquid density change, two state equations based on the positive relationship between p-ρ areestablished. And we select RNG k-ε turbulence model to take the simulation.In order to study the cavitation mechanism and its influence on the fluid fields, the fluidin the SCY-14B type swash plate axial piston pump were used to establish the model and takethe simulation analysis. Laminar flow state plus local turbulence settings and Zwart-Gerber-Belamri cavitation model were used in the numerical simulation of the internalflow field of axial piston pump. The contours of pressure, velocity, gas volume fraction atdifferent time and the pressure transient curves are obtained. The results of simulation withcavitation model and simulation without cavitation model were compared to get themechanism of cavitation and its impact on the axial piston pump. Some suggestions weregiven to avoid or reduce the occurrence of cavitation.