Schlieren and mie scattering visualization for single-hole diesel injector under vaporizing conditions with numerical validation

This paper reports an experimental and numerical investigationon the spatial and temporal liquid- and vapor-phase distributions of diesel fuel spray under engine-like conditions.The high pressure diesel spray was investigated in an optically accessible constant volume combustion vessel for studying theinfluence of the k-factor (0 and 1.5) of a single-hole axialdisposedinjector (0.100 mm diameter and 10 L/d ratio).Measurements were carried out by a high-speed imagingsystem capable of acquiring Mie-scattering and schlieren in anearly simultaneous fashion mode using a high-speed cameraand a pulsed-wave LED system. The time resolved pair ofschlieren and Mie-scattering images identifies theinstantaneous position of both the vapor and liquid phases ofthe fuel spray, respectively. The studies were performed atthree injection pressures (70, 120, and 180 MPa), 23.9 kg/m3ambient gas density, and 900 K gas temperature in the vessel.The predictive capabilities of the Lib-ICE code, which is a setof applications and libraries for IC engine simulationsdeveloped using the OpenFOAM® technology, were evaluatedin describing fuel sprays. The potential of the adopted set ofspray submodels employed, coupled with the two equationsRANS turbulence models available in the OpenFOAM toolbox,were analyzed through the comparison of numerical resultswith experimental data. The capability of simulations inreproducing the trends of liquid penetrations, temporal andspatial vapor distribution at increasing injection pressures andvarying nozzle configurations (k-factor) were considered.