Modeling of Air-Assisted and Flash Boiling Sprays in Gasoline Direct Injection Engines

Abstract

Impingement simulations were made for air-assisted sprays and flash boiling sprays. Both the air-assisted sprays and flash boiling sprays reduced fuel impingement substantially compared with a conventional GDI fuel injector. The air-assisted fuel injector produced the softest sprays in this study, but flash boiling may be more cost-effective for the automotive industry. The modeling methods developed by this work may be useful for the optimization and design of air-assisted and flash boiling fuel injectors in future GDI engines. Moreover, the simplified bubble growth model can be applied to the simulation of bubbly flows in many applications ranging from nuclear reactor coolant safety to refrigeration systems.