Study Of High Temperature Characteristic Of Electro-hydraulic Servo Valve And Testing System

As the key advanced control component of hydraulic servo system,electrohydraulic servo valve plays an important role in the field of aviation,aerospace and other national defense industries because of its high transmission power,fast response speed and high control accuracy.Electro-hydraulic servo valve has complex mechanical structure and high precision.Its stability,reliability and rapidity largely determine the control performance of electro-hydraulic servo system,and even affect the success or failure of aerospace missions.Aircraft hydraulic system,such as spacecraft launch vehicle servo mechanism,needs to withstand the harsh environment of high temperature and rapid temperature rise.Therefore,it is necessary to study the high-temperature characteristics of the nozzle flapper valve and build a high-temperature test system.Firstly,the source of temperature rise of servo valves in launch vehicles is described,and the current production and development status of high temperature servo valves are summarized.The content and significance of the research are clarified,and the technical route for the study of the high-temperature characteristics of the servo valve is put forword,the concrete scheme of setting up the high-temperature test system is also proposed.Based on the electro-hydraulic servo valve developed by AVIC 609 Institute,this paper analyzes the deformation of the nozzle baffle assembly of servo valve under high temperature by using the theory of heat transfer,deduces the temperature model of the valve under the steady temperature rise,and probes into the change of internal leakage of high temperature slide valve.Secondly,based on the ANSYS,the thermal-solid coupling of the nozzle flapper valve under the impact of temperature rise is analyzed and the thermal-fluid-solid coupling simulation under the steady temperature based on Fluent is accomplished.After iterative calculation,the temperature field nephogram of the servo valve is obtained.According to the two simulations,the temperature field difference of each part of the servo valve and the temperature change of the fluid part were analyzed to verify the theoretical analysis above.Finally,a high temperature test system for the electro-hydraulic servo valve was built.This test system included the static characteristics test of the electro-hydraulic servo valve and the temperature distribution of the electro-hydraulic servo valve body at high temperature.First,the hydraulic circuit diagram of the high-temperature testsystem was designed in accordance with aviation industry standards and actual conditions,and the selection of hydraulic components was completed.Then,the heating scheme of the pump station's oil tank was designed,the hardware system design and selection were completed,and finally a Labview-based high-temperature measurement and control system was developed,which broadened the idea of setting up the high temperature test system of electro-hydraulic servo valve.