Research And Analysis Of High Pressure And Large Flow Cartridge Proportional Unloading Valve

At present,my country's fully mechanized mining face equipment is developing in the direction of large-scale and heavy-duty.It has successfully developed a highyield and high-efficiency coal mining machine and hydraulic support with the largest mining height in the world of 8.8m.The emulsion pump station is used as the power source of the hydraulic support.Followed by constant updates.With the rapid development of intelligent fully mechanized mining technology,higher requirements are put forward for the quality of liquid supply in emulsion pumping stations.For highpressure and large-flow emulsion pumping stations,the discontinuity and poor reliability of the existing on-off electromagnetic unloading valve,and the trend of increasing liquid supply distance,lead to the supply pressure and output flow of the power source.Large fluctuations make the system pressure difficult to stabilize,large losses,large shocks,serious delays in liquid supply,and low component reliability.In order to solve this problem,this paper researched and designed a high-pressure and large-flow cartridge-type proportional unloading valve.In this paper,funded by the National Natural Science Foundation of China Joint Fund Project "Research on Downhole High Pressure,Large Flow and High Water-based Digital Valves and Their Control Methods"(U1910212),the high pressure and large flow cartridge proportional unloading valve was used as the research object,and the unloading valve was completed.The principle scheme design,mathematical model establishment and simulation analysis.The thesis mainly includes the following content:First of all,the characteristics of the high-water base fluid and the working conditions of the unloading valve are analyzed.Based on the working principle and performance characteristics of the unloading valve at home and abroad,the principle scheme design of the new unloading valve is completed according to the requirements of use.Including the main stage,the pilot stage,and the electro-mechanical conversion mechanism,the mathematical model was established and the design calculation of the main dimensions of the valve was completed.The spool and the valve sleeve under high pressure were checked by statics simulation.Second,using AMESim simulation software,a simulation model of the proportional unloading valve is established,and the influence of different parameters in the proportional unloading valve on the dynamic characteristics of the valve is analyzed.The simulation results show that the diameter and length of the pilot valve orifice have little effect on the dynamic performance of the valve,but when the pilot valve orifice is removed,the main valve will be unstable;the diameter of the pilot valve seat hole has a more significant i MPact on the valve dynamic characteristics.The reduction of the main valve outlet pressure fluctuation range shows a trend of expansion,the flow overshoot also increases significantly,the main valve is prone to turbulence,reducing the service life of the valve;the increase in the diameter of the main valve core orifice is beneficial to the system pressure The fluctuation range is reduced,the opening of the unloading valve core becomes smaller and smaller,and the flow overshoot also shows a decreasing trend;the spring stiffness of the main valve has a small effect on the dynamic performance of the valve.Under different spring stiffnesses,the main valve The oscillation time is basically the same.Co MPared with electromagnetic control,the pressure and flow fluctuation of the main valve port is smaller when the unloading valve is proportionally controlled,and the hydraulic shock during the pressurization and unloading process is also relatively reduced.Third,using Fluent simulation software to establish a three-dimensional flow field flow channel model of the main valve of the proportional unloading valve.The simulation analysis is carried out for different opening positions under rated pressure,different inlet pressures or different outlet pressures at the same opening position,and different spool half cone angles.The results show that the high-pressure fluid has the largest sudden change in speed and pressure drop at the valve port.The most serious place.Regardless of whether the inlet pressure is different or the outlet pressure is different,the greater the pressure difference,the greater the speed through the valve port,the greater the minimum pressure range,the easier it is to generate cavitation,and the greater the vortex,and the greater the energy loss.high.This article summarizes the analysis and design process of the high-pressure and large-flow cartridge proportional unloading valve.It takes structural design as the main line,and modern analysis tools such as ANSYS,AMESim and Fluent system simulation as auxiliary means.The design method of the high-pressure and large-flow cartridge proportional unloading valve is established,which provides a new research idea for improving the quality of liquid supply in emulsion pumping stations.The paper has 75 pictures,14 tables,and 62 references.