Research And Characteristic Analysis Of Safety Valve For Embedded Weapon Cabin Door Of A Fighter

With the emergence of related advanced airborne weapons,the weapons of contemporary fighter aircraft have changed from external hanging type to embedded type.Therefore,when the fighter carries on the combat mission,it must open the weapon compartment door for launching operation.As the cabin door will cause drastic changes in the flow field around it in the process of opening and closing,the loads on the cabin door will also change dramatically in different positions.Therefore,it is necessary to configure the open and close safety valve to control the formation of the allowable boundary and improve the operational reliability of fighters.So the design of the valve and performance analysis and parameter optimization are of great significance to improve its performance and subsequent application in the aviation field.Firstly,the mathematical model of the valve is established by the pressure-flow equation and other relevant hydrodynamic formulas,and the transfer function block diagram is drawn.Then the main structural parameters are selected.The simulation software AMESim is used to model and simulate the opening and closing safety valve.The simulation results show that the valve has good performance and stable response.Moreover,the structural parameters such as the front chamber of the main valve,the spring chamber of the main valve,the size of the front chamber of the pilot valve and the diameter of each damper hole have a significant impact on the static and dynamic characteristics of the valve.The study and analysis of the flow field distribution characteristics and negative pressure cavitation phenomena of the main valve port of the safety protection valve play an important role in optimizing the working performance of the valve.Based on the basic theory of computational fluid dynamics,the three-dimensional flow field model of the valve port is established and simulated by CFD fluid simulation software fluent.The static pressure cloud,velocity vector map and turbulent kinetic energy cloud of the main valve port flow field are obtained.The specific distribution characteristics of the valve port flow field,the size of the valve port pressure drop and the causes of cavitation are studied.The influence of the structure parameters such as the main orifice anti-half cone angle and the main spool roundness angle on the flow field of the valve orifice is analyzed,and the optimization direction is pointed out.The evaluation of the working performance of the valve has specific experimental requirements in the design requirements,including vibration function test,vibration endurance test and so on.In this paper,ANSYS workbench finite element software is used to simulate the valve.Pressure nephogram and life nephogram are produced.Remaining strength coefficients are solved to verify that the valve meets the requirements of specified working conditions.Field experiments were carried out on the hydraulic test bench of the safety protection valve,and the flow rate through the valve was regulated regularly.The pressure and corresponding flow data of the main valve port were recorded.The pressure and flow experimental curve was fitted by MATLAB to verify the design requirements of the valve and the reliability of the previous simulation.In a word,the design of the safety valve for embedded weapon cabin door has good performance,stable response and fully meets the requirements of the design working conditions.At the same time,the structural parameters of the valve are analyzed,and the optimization direction is put forward,which is conducive to improving the performance of the valve and making it work better.