| Twin flapper-nozzle servo valve is most widely used in electro hydraulic road system, is the typical component of conversion,amplification and control in hydraulic servo control system, plays a key role in the road system and is widely used in modern automatic control system. Compared to jet pipe servo valve, the servo valve possesses advantages of compact structure,excellent linearity,small dying area,quick response and reliable steady running etc. But low conversion and big energy consumption rate exist in the servo valve, defects such as the performance of the servo valves is improved on basic of analyzing servo valve internal flow field, the research has certain theoretical significance and practical value.This subject mainly completes three aspects: Firstly, the structural characteristics and performance characteristics of twin flapper nozzle servo valve are researched; Secondly, the prototype valve is simulated and calculated, from the view of flow field, the mathematical model and characteristic curve of the valve are realized; Thirdly, several key mechanism structural parameters of the prototype valve are optimized, and the optimum structure sizes are obtained. Firstly, this paper aims for is researching on twin flapper-nozzle servo valve of pre-amplifier , according to lead class twin flapper nozzle institution's flow distribution, and according to the actual situation of the pre-amplifier and the sizes of the pre-amplifier, the 3d geometry model of the twin flapper-nozzle servo valve is built by 3d geometry software Pro/E, and the models are meshed by the preprocessor GAMBIT of FLUENT software. Using computational fluid dynamics method, by normative both equation turbulence model, internal flow field of twin flapper-nozzle prototype valve is numerically simulated, then the valve pressure and velocity vector fields distribution and recovery pressure,recovery pressure of valve are obtained, and by quadratic function recovery fitting methods valves pressure and flow of recovery,the mathematic model are obtained, the impact of the model's structure on the flow characteristics inside is analyzed.Then on the basis of the prototype valve simulation, the variable valve orifice, fixed orifice and return oil orifice size of several important parameters are optimized. Using the same method and the prototype valve for different models of the different size calculation models, the models'characteristic curve compared with the ideal characteristic curve, the optimal structure size, at last the optimized dimensions of purpose is reached.This paper from the view of flow field analysis, has built the mathematical model of twin flapper nozzle amplifier, several important dimensions for twin flapper nozzle servo valve are optimized. The paper provides a new thinking line for the establishment of the mathematical model, and provides a foundation for an overall performance optimization for valve. |
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