Flow Distribution Simulation And Experiment Study Of The Jet Deflector Servo Valve's Pre-stage

The jet deflector servo valve is the key component of hydraulic system.The pre-stage flow field distribution and fluid motion law affect the life of the valve and the performance of the entire valve-control system.Due to the irregularity of the pre-stage structure,the flow field distribution is very complicated.The slight change of structure will greatly affects the flow field characteristics such as pressure and gain of the receiving cavity.Therefore,in order to optimize the pre-stage structure parameters and guide the servo valve design and production,it is necessary to establish accurate pre-stage mathematical model,simulation model and research on the pre-stage flow field.The paper mainly studies the flow field characteristics of the pre-stage of jet deflector servo valve.First of all,the pre-stage's jet flow field is divided into four parts,which are investigated respectively by utilizing the knowledge of fluid mechanics and jet mechanics.Then,the mathematical models of pressure and velocity in flow field are established,and the flow field distribution at the key position is obtained.Numerical simulations are conducted to verify the mathematical model for the two-dimensional flow field.Furthermore,the three-dimensional flow field in the pre-stage is explored,and the two flow field models are compared.The flow pattern is studied by using cloud chart,streamline chart and stereoscopic vision chart.The difference between the two fields are found in the first jet's inlet,V-groove and receiving surface respectively.The results show that there are obvious spatial flows in the structure of the pre-stage.The complex shape of the three-dimensional flow field is analyzed to illustrate the deficiency of the two-dimensional model.Finally,experiments on pre-stage characteristic of the jet deflector servo valve are carried out.Through testing the flow field receiving cavity pressure by pre-stage characteristic parameter test bench in different conditions of deflection plate,the effectiveness and correctness of the flow field numerical analysis are verified.In this paper,the accurate two-dimensional mathematical model of pre-stage flow field is eatablished.The three-dimensional simulation model is used for the first time on the basis of two-dimensional numerical simulation.Combinating with pre-stage characteristic parameters test,the accurate flow information of the key region of the pre-stage flow field is obtained,and the flow pattern of the pre-stage can be described more fully.The research results have improved the theoretical system of the flow field characteristics of the pre-stage,which lays a theoretical foundation for the study of the flow field characteristics of the jet deflector servo valve's pre-stage,and it also provides guidance for the improvement of the servo valve's performance and the structure optimization.