| Electro-hydraulic servo valve has the advantages of high performance, high reliability,low power consumption and small size, light weight and other characteristics, so it is usedwidely in aviation and aerospace in electro-hydraulic servo system. At present, doublenozzle flapper force feedback two-stage servo valve is representative, the first stage ofwhich is double nozzle flapper valve, its performance has an important influence on theperformance of the electro-hydraulic servo valve. This paper takes a commissioned projectof one aviation group company as the background, analyzing characteristics of thepreamplifier stage of the two-stage servo valve——double nozzle flapper valve, whenchanging the structural and technical parameters, searching the best parameters; Andestablishing function of the double nozzle flapper valve which basing on fluid-solidcoupling, and analysis the influencing factors; Setting experimental research on doublenozzle flapper valve of the main parameters that influencing the performance of thedouble nozzle flapper valve.In this thesis, numerical simulation model of different structural parametercombination of the double nozzle flapper valve is established firstly, which aimed at thepreamplifier stage of double nozzle flapper servo valve of one group company. Thesestructural parameters such as: the diameter, the length, the inner angle, the cavity diameterof the fixed orifice; and the diameter, the length, the inner and outer angle, the cavitydiameter, the transverse diameter of the nozzle; the diameter of the return oil orifice andzero distance and so on. Analyzing the the interior flow field performance of the doublenozzle flapper valve, and caculating the flow efficient and the power loss, usingorthogonal test method to find out the primary and secondary factors that affecting itsperformance, and the same time find out the best parameter combination of the doublenozzle servo valve which has the minimum power loss.Secondly, the changing of the working condition can influence the flow field of thedouble nozzle flapper servo valve, such as oil supply pressure, oil return pressure, oiltemperature and baffle deflection, and so on. In order to study the primary and secondary factors affecting the flow field when these external parameters change, by usingorthogonal test method to establish numerical simulation model that has differentparameters, through analysis and calculation finding out the best parameter combinationthat has the minimum power loss.And then, with the changing of the parameters of the double nozzle flapper valve theflow field will be changed, the same time the changing flow field will effect on the flapper,based on the fluid-solid coupling effect, the mathematics model of the doubleflapper-nozzle servo valve with the elastic flapper was established, and the influence ofthe stiffness of the flapper on the performance of the servo valve was analyzed.Orthogonal test is used to analyze the changing of the pressure and the flow field of thedouble nozzle flapper valve when changing the parameters, the proposed researchanalyzes the influence of the flapper stiffness on the double flapper-nozzle servo valve,and provides the theoretical basis for the design of the flapper-nozzle force feedback servovalve.Lastly, with one certain type of double nozzle flapper servo valve as the experimentaltest object which provides by one group company, testing the static consumption of thevalve when changing the the fixed orifice diameter, distance between nozzle and flapper,and the oil temperature, and then comparing with the numerical results obtained, findingthat experimental testing and numerical calculation results are basically identical, whichverified the correctness of the calculation model and numerical simulation, which has areference value for the design and analysis of the double nozzle flapper servo valve. |
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