Research On Flow Field Characteristics Of Pre-stage Of Deflector Jet Servo Valve

The deflection plate jet servo valve has the advantages of simple structure,high control accuracy,good linearity of pressure gain and flow gain,large frequency response range,and reliable operation.It is currently widely used in high-tech fields such as aerospace and aviation.The pre-stage is a key component of the deflection plate jet servo valve.Its quality not only affects the steady-state performance of the servo valve such as pressure gain and flow gain,but also affects the stability of the entire system.The structure of the pre-stage is fine,and its internal jet flow field is very complicated.It is often accompanied by phenomena such as oil backflow,entrainment and eddy current.When the structure parameters of the pre-stage or the fluid viscosity changes slightly,it will affect the whole of the deflection plate servo valve.Performance has a big impact.Therefore,studying the influence of different pre-stage structural parameters and oil viscosity on the static characteristics,dynamic characteristics and cavitation of the servo valve is of great significance for improving the performance and stability of the servo valve.This paper uses CFD software to study the internal flow field characteristics of the pre-stage,combined with the pressure cloud diagram and velocity cloud diagram,the focus is on the analysis of the receiving hole fillet,deflection plate thickness,nozzle width and oil viscosity on the pre-stage pressure of the deflection plate servo valve.Characteristics and the influence of flow characteristics.In order to study the degree of influence of different structural parameters on the pressure characteristics of the pre-stage,this paper uses two statistical methods of gray correlation analysis and orthogonal experiment to study the influence of different structural parameters such as nozzle width,receiving hole fillet,and deflector thickness on deflection.Based on the influence of the pressure characteristics of the pre-stage of the plate servo valve,the matching scheme of the thickness of the deflection plate corresponding to the width of the nozzle and the size range of the fillet size at the receiving hole is proposed.The range of the best combination is obtained.Aiming at the phenomenon of backflow,entrainment and vortex in the pre-stage jet flow field,which leads to the appearance of cavitation,this paper analyzes the distribution and content of cavitation in the internal flow field of the pre-stage under the gas-liquid two-phase flow model.The research analyzes the influence of the change of the receiving hole fillet,the thickness of the deflection plate and the oil viscosity on the cavitation phenomenon.According to the existing empirical formulas,the mathematical model of the entire valve of the deflection plate servo valve was established.The MATLAB/SIMULINK software was used to analyze the different receiving hole fillets,deflection plate thickness and oil under the frequency response characteristics and time domain response characteristics.The effect of viscosity on the dynamic characteristics of the deflection plate servo valve.