Simulation study on the cavitation distribution in the ball valve of a common rail injector

Abstract

A transient-state numerical simulation is conducted to investigate the cavitation flow in the ball valve of a common rail (CR) injector. The computational fluid dynamics (CFD) software, employing the RANS turbulence model, is employed for this purpose. The study aims to analyze the characteristics and underlying causes of the uneven distribution of cavitation in the ball valve. The results reveal a significant occurrence of cavitation, exhibiting an uneven distribution along the walls of both the ball and the valve seat. Notably, the initiation position of the intense cavitation region on the wall of the ball is observed to lag behind that on the wall of the valve seat. The intense cavitation region on the wall of the ball is found to reside behind the sealing surface of the ball valve. The intense cavitation region on the wall of the ball is located behind the sealing surface of the ball valve. This region experiences flow separation caused by main flow detour, resulting in the formation of vortices that entrapped the cavitation cloud, thus fostering the development of intense cavitation. Conversely, the intense cavitation region on the wall of the valve seat originates from the entrance of the ball valve. This can be attributed to the sudden change in geometry at the entrance, leading to a significant pressure drop and inducing cavitation based on geometric factors. Furthermore, the stagnation effect caused by the ball exacerbates the discrepancy in the distribution of the intense cavitation region between the ball and the valve seat.