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

This paper reports an experimental and numerical investigation on 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 opticallyaccessible constant volume combustion vessel for studying the influence of the k-factor (0 and 1.5) of a single-hole axialdisposed injector (0.100 mm diameter and 10 L/d ratio). Measurements were carried out by a high-speed imaging system capable of acquiring Mie-scattering and schlieren in a nearly simultaneous fashion mode using a high-speed camera and a pulsed-wave LED system. The time resolved pair of schlieren and Mie-scattering images identifies the instantaneous position of both the vapor and liquid phases of the fuel spray, respectively. The studies were performed at three injection pressures (70, 120, and 180 MPa), 23.9 kg/m3 ambient gas density, and 900 K gas temperature in the vessel. The predictive capabilities of the Lib-ICE code, which is a set of applications and libraries for IC engine simulations developed using the OpenFOAM® technology, were evaluated in describing fuel sprays. The potential of the adopted set of spray submodels employed, coupled with the two equations RANS turbulence models available in the OpenFOAM toolbox, were analyzed through the comparison of numerical results with experimental data. The capability of simulations in reproducing the trends of liquid penetrations, temporal and spatial vapor distribution at increasing injection pressures and varying nozzle configurations (k-factor) were considered.