Flow Field Analysis And Integrated Modelling Of Three-stage Jet Pipe Electro-hydraulic Servo Valve

With the development of science and technology in our country,many large devices put forward higher demand on the flow rate,frequency response,resolution,precision and reliability of electrohydraulic servo valves,especially in the large flow rate performance,the traditional two-stage electro-hydraulic servo valve is far from meeting the requirements.Compared with the nozzle flapper valve,the jet pipe servo valve has the advantages of high hydraulic efficiency and volume efficiency,strong anti-pollution ability,high sensitivity and resolution,high reliability,and return to middle position after failure,so it is imperative to conduct in-depth research on the three-stage electro-hydraulic servo valve with the jet pipe servo valve as the front stage.However,due to the complex structure of the jet pipe servo valve and the lack of a complete mathematical model of the flow field inside the fluidic amplifier,it is difficult to predict the performance of the three-stage jet pipe electro-hydraulic servo valve.In this paper,a mathematical model of three-stage jet pipe electro-hydraulic servo valve is established and numerical simulation is carried out to study the influence of its structural parameters on dynamic response.On the basis of analyzing the structure and working principle of the three-stage jet pipe electro-hydraulic servo valve,through deducing the mathematical model of each link,and its overall mathematical model is established.In view of moment motor,finite element model of armature and feedback rod assembly is set up,and that influence of length,cross sectional area,cross section shape and material on the feedback rod stiffness is analyzed.For the internal flow field of the jet amplifier,using the FLUENT software to analyze the impact of the spacing between nozzle and receiving holes and the angle of the wedge on flow field static characteristic.Based on the above analysis and the obtained parameters,the MATLAB/Simulink model is established,focusing on the analysis of the influence of structural parameters such as feedback rod stiffness,nozzle and receiver hole spacing,wedge angle,and valve core area of main stage slide valve on dynamic response.This article provides some reference value for the design and development of the three-stage jet pipe electro-hydraulic servo valve.