Dynamic behavior and mechanism analysis of tip wetting process under flash boiling conditions

The increasingly stringent emission regulations have required that the State-of-the-art internal combustion engines operated with minimum particulate matters produced. Flash boiling spray is considered to be potential technology for achieving high efficiency combustion, its benefit of improving fuel-air mixing process in cylinders and eliminating spray-wall impingement. On other side, it believed flash would also enhance injector tip wetting phenomenon since widened plume interact pre-hole more frequently, causing sooting deposits. However, understanding physics related film formation, propagation evaporation still lacking existing literature. This investigation focused on a two-hole gasoline direct injection (GDI) fuel injector, characteristics were analyzed optical means. High-speed imaging was used illustrate dymanics near field, laser-induced fluorescence capture clear footprints film. Various boundary conditions, such as temperature, ambient pressure, durations investigated figure out their impacts process. It found could divided into two stages, namely wide induced dribble wetting, among which primary cause wetting. Besides, impact analyze aspects. enhanced effect finner significantly increase deposited onto tip, while strong evaporating nature can help eliminate negative effects from atomization.