| Double flapper- nozzle servo valve is an important element of the servo control system, widely used in industrial development. The research object is MOOG-G761 servo valve. When the oil flow occurs in valve, speed and pressure will change. At the same time, flow force and the viscous friction force on spool will be given. And then, the movement of the internal structure of the servo valve will change. Therefore, the dynamic and static characteristics and the flow field distribution are analyzed. According to the simulation results, the stability of the servo valve is analyzed.Firstly, the working principle of servo valve and testing system are introduced. For the experimental conditions and the servo valve static and dynamic characteristics will be described, to obtain the experimental curve, as models basis of the flow field and AMESim simulation. The servo valve split to get the internal structure parameters, providing the basis for establishing the simulation model.Secondly, the use of Fluent software in the spool stationary state, in different throttle modes and different valve opening, comparing the flow field distribution of the oil, get the area of vortex and pressure changes in the big region. Analysis the trend of spool steady flow force in different throttle modes, based on the speed distribution of the fluid.Finally, use AMESim software to build double flapper- nozzle servo valve simulation model, the simulation curve and experimental curves were compared to verify the accuracy of the ideal model. According to Fluent calculated steady-state flow force, set flow force coefficient. Then the article makes an analysis on the movement of the internal structure of the servo valve under the influence of flow force. When the spool is affected by flow force, pressure and speed at both ends of the spool valve chamber changes. And then the viscous friction will change, therefore reducing coefficient of viscous friction. Change the viscous friction, do further simulation analysis. |
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