A unified fuel spray breakup model for internal combustion engine applications.

Abstract

A unified approach towards modeling fuel sprays for internal combustion engines has been developed in this work. Based on a Lagrangian approach, the fuel injection process has been divided in three main subprocesses: primary atomization, drop deformation and aerodynamic drag, and secondary atomization. Two different models have been used for the primary atomization, depending on whether a high-pressure swirl atomizer or a multi-hole nozzle is used. The drop deformation and secondary atomization have been modeled based on the physical properties of the system, independent of the way the droplets were created. The secondary atomization has been further divided into four breakup regimes, based on experimental observations reported in the literature. The model has been validated using a wide array of experimental conditions, ranging from gasoline to diesel sprays. For both types of sprays, low and high ambient pressures have been used, and for the diesel sprays different injection pressures have also been utilized. Finally, the capabilities of the model are illustrated by presenting gasoline and diesel engine simulations. Overall, the model performs satisfactorily, without the need for recalibration for each condition. Small discrepancies between model predictions and experimental measurements are observed for some cases, but they can be principally attributed to uncertainties in the boundary conditions and the primary breakup modeling.