Hollow cone spray characterization and integral modeling

Gasoline direct injection (GDI) has been widely introduced in todays internal combustion engines for automotive applications. One way to increase the engines efficiency is to reduce throttling losses. This engine operation mode requires the stratification of the fuel air mixture within the combustion cylinder. Hollow cone injectors enable such mixture stratification. The present work investigates the spray formation resulting from the injection of liquid fuel into air by a hollow cone injector. A methodological overview establishes the need of a fast spray model to simulate the engine operation at a system level. A detailed insight into the fluid mechanics of a hollow cone two-phase jet is obtained by means of a computational fluid dynamics (CFD) investigation. The model is validated experimentally both by the global penetration behavior and by the velocity field outside of the dense spray. Based on the characterization of the hollow cone two-phase flow, a one-dimensional model is derived. It describes the temporal evolution of the two-phase jet induced by the hollow cone injection process. Diffusive transport of mass, momentum, and energy between the dense spray zone and its environment is modeled by means of a boundary layer description.