Dynamic Coupling Analysis Of Valve Flow Field And Valve Motion Of Reciprocating Pump

Reciprocating pump has the advantages of high discharge pressure,strong self-priming ability,high efficiency and constant flow.It has significant advantages in transporting high viscosity,flammable,explosive and corrosive liquids.It is widely used in petrochemical,smelting,naval and military fields.During the working process of reciprocating pump,the inlet and outlet one-way valve core falls back to the valve seat at a high frequency and speed.Under the high frequency impact load,the valve and valve seat is easy to be damaged and even causes serious accidents.In this study,in order to study the movement law of the spool and the reliability of the lifting valve,the transient characteristics of pump valve motion are analyzed under different spring stiffness,preload,limit height and connecting rod ratio.The main work of this paper is as follows:1.In order to accurately analyze the transient motion characteristics of the valve of reciprocating pump,the motion analysis of the valve is coupled with the numerical simulation of the flow field in the valve gap,and the motion law of the valve is obtained according to the flow field analysis of the valve gap,the force on the valve and the motion analysis of the valve.The dynamic update of the grid of the valve motion area is realized by the dynamic grid technique.2.In the case of different spring stiffness coefficients and preload,the transient characteristics of valve motion are simulated by dynamic grid technique and UDF method,and the motion states of valve under different working conditions are obtained.The influence of spring stiffness coefficients and preload on lift is analyzed.The analysis results show that the greater spring stiffness and preload are,the greater valve lift is.With the increase of spring stiffness and pre-tightening force,the lag height of valve decreases,and the volume efficiency of pump increases.The influence of spring stiffness and preload on volume efficiency is mutually restricted by its influence on hydraulic efficiency and suction performance.3.The influence of the height of the limiter on the hysteresis characteristics of the valve and the impact load of the valve on the limiter is studied.The analysis results show that the hysteresis height of the valve core first decreases and then increases with the increasing of the height of the limiter,and there exists an optimal range of values for the value.The higher the height of the limiter is,the smaller the impact load of the valve on the limiter is.At the same flow point,with the increase of the height of the limiter,the vorticity intensity in the clearance area between the valve core and the valve seat decreases gradually.4.Coupling analysis of plunger motion and spool motion is carried out to study the relationship between spring stiffness,preload and seat impact,the impact load on the valve seat,the valve core hysteresis characteristics,and the pressure variation law of plunger working face.The analysis results show that the influence of spring stiffness and preload on seat impact to the valve hysteresis angle and the hysteresis height of valve are related to the influence of that to the spring stiffness and preload.The influence law is basically the same.In the discharge stroke,with the increase of spring stiffness or preload,the pressure of plunger working face increases,while in the inhalation stroke,with the increase of spring stiffness and preload,the pressure of plunger working face decreases;the larger the spring stiffness is,the more work needs to be done under the same discharge pressure and flow rate conditions and the larger the hydraulic loss at the valve gap will produce.The closing hysteresis characteristics of the suction and discharge valves are simulated accurately.