A numerical analysis of flow-induced phenomena in the deflector jet pilot stage valve for flapper misalignment

In the industry of aerospace, mechanical, and aerodynamics, the servo-valve has been essential in providing precise control. The paper includes a numerical analysis of flow-induced phenomena in the deflector jet servo-valve, with emphasis on flapper misalignments due to long-term use or improper installation. Simulations with the use of STAR CCM+ were performed for −0.005 mm to 0.005 mm lateral movement of the flapper with 1-degree anticlockwise and clockwise misalignment for 24 MPa supply pressure and 0 MPa outlet pressures. Findings indicate that even a slight change in flapper installation considerably changes pressures in receiving ports, velocity distribution, and cavitation. As a result, pressure differentials at receiving ports cannot be achieved. It is also observed that malfunctioned positions created a higher intensity of cavitation than the traditional model. The results highlight the importance of the proper flapper placement to achieve high-performance of the valve and indicate that the appropriate position of the deflectors reduces the undesired flow effects, permitting more reliable performance.