Coupled LES Jet Primary Breakup - Lagrangian Spray Simulation of a GDi Multi-Hole Fuel Injector

This paper presents results of a coupling of the Volume-of-Fluid Large-Eddy simulation (VOF-LES) of the jet primary breakup with a Lagrangian stochastic spray simulation of a GDi multi-hole injector. The objective is to assess the potential of replacing the phenomenological models of jet primary atomization with the stochastic parcel size - velocity data extracted from the VOF-LES analysis. The paper describes the methodology and assesses the predictive capability achieved, through comparison of the Lagrangian far-field spray simulation results with the complete experimental spray characterization data under the atmospheric ambient conditions. The injector sac-nozzle flow and jet primary breakup simulation is performed with the Open-FOAM code. The simulation of the spray development processes - of propagation, evaporation and secondary atomization - is performed with the AVL-FIREcommercial CFD code adopting the standard Lagrangian discrete droplet method. The comparison demonstrates good quantitative agreement for prediction of all significant far-field spray plume parameters, notably the trajectory, spread angle, tip penetration, foot-print pattern and the droplet-size probability distribution function.