Multi-dimensional simulation of the fuel air mixing process in common rail engine operating with high injection pressures

Purpose of this Thesis work is the implementation of a secondary break-up model to simulate spray evolution. Such model was implemented into the Lib-ICE code, an OpenFOAM based set of libraries tailored for the simulation of Internal Combustion Engines, that is developed by the ICE research group of the Politecnico di Milano. The validation of the model was carried out considering non-evaporating and evaporating conditions, steady and unsteady injection profiles, constant volume and in-cylinder experiments; all the cases were run without combustion reactions. The experimental data were provided: by the Istituto Motori Napoli - CNR for the non-evaporating conditions under four different injection strategies, by the CMT Motores Termicos of the Universitat Politecnica de Valencia for the evaporating parametric variations of the gas phase density and temperature. Literature data were used to validate the proposed model in an engine configuration. The variables compared in the validation are the liquid and vapor penetration lengths, the Sauter Mean Diameter (SMD) at different distances from the injector nozzle hole, and mixture fraction distributions.