| Deflector jet servo valve has the advantages of simple structure,reliable operation and strong anti-pollution ability,so it is widely used in aviation,aerospace and other fields.As the core component of aero-engine control system,fuel electro-hydraulic servo valve plays an important role in aero-engine performance.Compared with ordinary electro-hydraulic servo valves,the working environment temperature range of fuel electro-hydraulic servo valves is large,resulting in serious zero drift of fuel electro-hydraulic servo valves.Therefore,it is of great significance to study the flow characteristics of the pre stage in the wide temperature range micro asymmetric structure of the deflector jet fuel electrohydraulic servo valve.Firstly,the working principle and related structural features of the deflector jet servo valve are introduced.According to the theory of fluid mechanics and jet mechanics,the front flow field of the fuel deflector jet servo valve is simplified into the process of primary jet and secondary jet,and its mathematical model is established.Secondly,the thermal deformation of the key structural parameters of the jet disk and deflector plate in wide temperature range is analyzed,and the change rule of the key structural parameters of the pre-stage with the temperature is obtained.The pre-stage structure is optimized to lay the foundation for the subsequent analysis of the pre-stage fluid flow characteristics under a wide temperature range micro-asymmetric structure.Thirdly,the numerical analysis model of the flow field in the pre-stage is established,and the characteristics of the pre-stage fluid flow in a wide temperature range are simulated,and the influence of temperature on the pressure characteristics of the pre-stage is obtained.The flow characteristics of the pre-stage in the case of longitudinal asymmetry of the deflection plate are studied,and the influence of the longitudinal deviation of the V-groove on the pressure characteristics of the pre-stage is obtained.The influence of key structural parameters such as incident port,primary jet port,V-groove angle,secondary jet port and wedge width on the pressure characteristics of the pre-stage is analyzed,and the influence weight of the key structural parameters of the pre-stage on the zero drift characteristics of the servo valve is obtained.The pressure characteristics of the pre stage in the wide temperature range of micro asymmetric structure are studied,and the maximum deviation satisfying the zero drift requirements of the servo valve in the wide temperature range is obtained.Finally,an experimental model of the pre-stage flow field of the servo valve is designed according to the Reynolds similarity criterion.The flow visualization technology is used to measure the internal flow field of the pre-stage,and the liquid flow characteristics of the pre-stage are obtained under different unsymmetrical deflectors.Compared with the numerical simulation results and the correctness of the numerical simulation is verified.The research results provide a theoretical basis for the design,processing and assembly of the fuel deflector jet servo valve. |
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