Performance and Flow Field Analysis of Flapper Deflection Servo Valve

Nowadays, more and more attention has been paid to the flapper deflection servo valve for its long service life and lasting antifouling. As a core part of flapper deflection servo valve, deflector pilot stage’s performance has a serious impact on the capability of the entire servo valve. Aiming to improve the performance of deflector pilot stage and observing the cavitation variation of flow field, this paper establishes a suitable numerical simulation model of the deflector pilot stage by software STAR-CCM+. New performance parameter whose name is pressure-sensitive coefficient number is proposed to reflect the character of pressure variation in deflector pilot stage. By changing the configuration of inlet nozzle, the cavitation variation and pressure-sensitive coefficient number are analyzed to get a higher performance. At last the best size is obtained which include the height, width and the position of symmetrical characteristic.