| Deflector jet servo valve is a kind of jet servo valve. It inherits the advantages of jet pipe servo valve which possesses high control precision, strong anti-pollution ability, and long life; besides, it also has the advantages of small pre-stage rotational inertia, good flow gain and pressure gain degree of linearity. Therefore, deflector jet servo valve which has very broad application prospects in engineering has been widely used in aviation, aerospace, shipbuilding, metallurgy and other related technical fields. The pre-stage flow field of deflector jet servo valve is very complex, and the products which domestic related research institutes and enterprises development still have a great gap compared with foreign products. In this situation, research on deflector jet servo valve has very important theory significance. Researches on the deflector jet servo valve in this paper are shown as following:Firstly, the working principle and structural features of deflector jet servo valve are researched, and magnetic circuit equations of torque motor assembly are analyzed combined with the second law of Kieler Hof and the Maxwell equation, then the driving torque mathematical expression of the motor torque is acquired. Based on the motion law of deflector jet servo valve pre-stage internal flow field, the numerical analysis of the flow field model is carried out, and the flow linearized equations are derived, which leads to the necessity of flow field simulation. By analyzing the forces applied on the deflector and spool, the motion mathematical models of both components are obtained. Based on the mathematical model of each component, the transfer function between the spool displacement and the drive current is established according to the principle of automatic control.Secondly, to establish pre-stage flow field analysis model by combining the pre-processing grid division software ICEM with the Fluent fluid simulation software, the pressure model and flow model of deflector jet servo valve pre-stage are analyzed, and the simplified model is constructed by using Pro/E. Studying the regulation of two receving holes differential pressure and flow with the deflector displacement variation, the pre-stage linearized flow equation is achieved. Meanwhile, gas content and gas distribution of pre-stage flow field are studied in multiphase flow model. The influence of nozzle width, deflector guide groove angle and wedge width on the pressure characteristic is discussed.Thirdly, based on the transfer function of deflector jet servo valve spool displacement and driving current derived above, its dynamic characteristics, including frequency domain characteristic and time domain characteristic, are analyzed by using MATLAB software, and the influence of different structure parameters on the dynamic performance is also disscussed.Finally, experimental research is given about static characteristics of deflector jet servo valve, and the experimental results are compared with actual performance parameters. Besides, the frequency characteristic curves of deflector jet servo valve are measured by servo valve dynamic test system, and the results are compared with the simulation results, which verify the correctness of the mathematical models built in this paper. |
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