Internal Leakage Analysis And Flow Pulsation Study On Double-action High Pressure Vane Pump

As the vane pump develops toward high pressure and high speed,the flow pulsation restricts the improvement of its working performance,and the flow pulsation brings a series of problems such as noise,pressure shock,cavitation and vibration.The flow pulsation of vane pump is mainly caused by internal leakage and oil displacement change in the working chamber.There is leakage flow in the gap between the motion pairs inside the vane pump.The increase of working pressure will further expand the internal leakage flow,and at the same time,the increase of rotating speed will reduce the suction energy of the vane pump,aggravate the cavitation phenomenon in the working chamber and flow reversal.Therefore,the high pressure and high speed of the vane pump will bring more flow pulsation.Aiming at the flow pulsation problem inside the vane pump,this paper studies the problem by theoretical analysis,numerical calculation and simulation.The main contents are as follows:1)According to the gap flow mode inside the vane pump,the inte rnal leakage mathematical model is established.The leakage variation under different working conditions is analyzed and calculated.The axial gap flow is calculated as the main leakage path,and the volumetric efficiency mathematical model of leakage loss is established.The effects of temperature,speed and axial gap on volumetric efficiency were analyzed.2)The pressure distribution and velocity vector distribution in the distribution sub-oil film are obtained by simulation.The pressure distribution on the oil film and the flow direction of the oil are basically consistent with the theoretical analysis of the leakage path.The simulated leakage and theoretical leakage are compared to prove the accuracy of the analysis method of the theoretical leakage m odel,which provides theoretical support for studying the leakage inside the high pressure vane pump.According to the power loss of the distribution pair,the optimal oil film thickness of the distribution pair theory is calculated.3)The complete flow path calculation model of the vane pump is established,and the internal pressure and cavitation changes during the rotation of the working chamber are simulated and analyzed.When the working chamber and the oil discharge area are connected,the high pressure oil will flow back into the working chamber,thus it brings a certain pulsation to the flow.The cavitation occurs at a position where the pressure is abrupt and the oil flow rate is fast.The most serious position of the cavitation in the oil suction zone occurs near the midpoint of the stator transition c urve.4)The effects of different inlet pressure,outlet pressure,rotation speed,number of blades and the gap between the blade and the inner wall surface of the stator on the flow pulsation and pressure pulsation of the vane pump are analyzed.It is concluded that the influence of inlet pressure on flow pulsation is greater than that of outlet pressure,and the cavitation range and intensity of oil absorption area will increase with the increase of rotating speed.As the number of blades and the gap between the blades and the inner wall of the stator increasing,the flow pulsation and pressure pulsation will be improved,but the average flow rate of the output will be correspondingly reduced.