CFD modeling of spray evolution for spark-ignition, direct injection engines

Abstract

Continuously more stringent regulations on pollutant emissions for gasoline internal combustion engines require a deep understanding of the effects that direct fuel injection exerts on the combustion process. Computational fluid dynamics simulations nowadays represent a powerful instrument to investigate these phenomena, nevertheless it is still fundamental to pursue their optimization by means of results validation against experimental data. Within this context, a validation of a comprehensive set of numerical spray sub-models for gasoline direct injection simulations is proposed in this work. The baseline condition of the Engine Combustion Network (ECN) Spray G injector was simulated in vessel by means of a Lagrangian-Eulerian RANS approach and achieved results were compared with reference experimental data available from literature and from the latest ECN Workshops. Particular focus was put on the prediction of mandatory quantities for gasoline sprays such as axial liquid and vapor penetrations, air entrainment, air-fuel mixing and spray morphology. Results show that a satisfactory agreement with experimental quantities was achieved, with the proposed methodology which is capable to predict the main aspects of a typical gasoline direct injection process.