Study On Flow Characteristics Of Axially Inclined Plunger Pump With Oil Containing Gas

The hydraulic pump,as the hydraulic power component,holds a very important position in the hydraulic system.Among all kinds of hydraulic pump,the axial pistion pump is widely used in industrial and walking hydraulic system,because of the axial pistion pump has the advantages such as high rated pressure and efficiency,small size and long lifecycle.Due to the influences of its working principle,the axial pistion pump always have flow ripple in the outlet of pump and pressure overshoot or undershoot in the pistion chamber,the flow ripple and pressure overshoot or undershoot are collectively called as flow characters of the axial pistion pump,and the flow characters is the key influence factor of noise in axial piston pump.Therefore,this thesis takes one axial piston pump with concial cylinder as the main researching object,with the purpose of improving the accuracy of the theoretical and simulation model of the flow characters and reducing the flow ripple and pressure overshoot or undershoot,moreover,the research methods and conclusion in this thesis definitely have theoretical and practical value.The main research work of the thesis are as follows:1.The research background,aim and significance of the the thesis were discussed,then,the current research overview about the axial pistion pump’s flow characters was investigated and summarized,and the research methods and contents are presented accordingly.2.The theoretical model of the fluid properties of air-liquid mixture of hydraulic oil was established based on the definition of the fluid properties and law of mass conservation,especially,the theoretical model of effective bulk modulus of below the saturation pressure was established and intensively studied,by the comparison of the numerical calculation and published literature’s results,verifing the accuracy of the theoretical model of effective bulk modulus,as well as,the influence factors of the effective bulk modulus were analyzed.3.The analysis of pump’s kinematics and dynamics were carried out based on the structural components and working principle of the axial pistion pump with concial cylinder,besides,the eqution of pump’s kinematics and dynamics were established and the influence factors of the pump’s kinematics was analyzed.The pressure-rise-rate equation for the control volume within a piston chamber was established and the mathematical model and calculation equation of leakage flow was proposed,what’s more,the calculation of the flow area of valve plate was carried out.4.The generic simulation model of fluid properties and single piston/swash plate mechanism were developed by using AMESet,which according to the theoretical model of the fluid properties and the eqution of pump’s kinematics and dynamics.The simulation model of single pistion and valve plate were developed by using AMESim,which according to the pressure-rise-rate equation and calculation equation of leakage flow and the flow area of valve plate.At last,the simulation model of whole pump was developed by using AMESim.5.The effect of the operating conditions and the structural parameters on fluid characters were simulated based on the former simulation model,the operating conditions including the intial air content,speed of shaft and the load pressure,the structural parameters incluing the angle of swash plate and pistion dip angle.What’s more,the effect of the transition region of the valve plate were simulated,and the optimization selection of the transition region of the valve plate was presented.At last,the optimization of all the parameters of the transition region of the valve plate was carried out.