3차원 CFD 상세 유로모델을 이용한 커먼레일 디젤인젝터의 내부 유동특성 분석

Advanced combustion technologies for common-rail diesel injection engines require high performance fuel injectors. Therefore, computational predictions of the diesel injector performance have been performed to evaluate internal flow characteristics on the needle lift and the spray pattern at the nozzle exit. However, when the injector is in operations, only some flow driven out of the injector by pressure drop at the nozzle exit, the others flow is returned to fuel supply lines through a spool valve for needle lift control. Actually, the internal flow passage of an entire injector duct including injection and return routes has never been adopted for three-dimensional computational fluid dynamics(CFD) analysis. In this study, the computational prediction of the internal flow characteristics of the entire injector duct in the common-rail diesel injector is carried out by using STAR-CCM+ 7.04 code. For this, computations were carried out under the assumption that the internal flow passage is a steady-state condition at the maximum needle lift. The results show that pressure and velocity profiles of the this model, we found that the very thin flow passages appear a pressure drop and velocity increase. In particular, the study focuses on the uniformity index due to flow rate deviation between the needle entrance and the nozzle exit.