SPRAY CHARACTERIZATION FROM HIGH-PRESSURE OUTWARDLY OPENING HOLLOW CONE INJECTOR FOR AUTOMOTIVE ENGINES

This study concerns an experimental and numerical activity on a prototype of an outwardly opening hollow cone injector as a possible application for automotive engines. An external supplier provided the prototypal injector, with a dedicated piezoelectric actuation system, and with an appropriate choice of geometrical design parameters, working at high injection pressure. The characteristics of nozzle open spray concept (in terms of spray penetration and diffusion) were evaluated in a constant volume combustion bomb and validated by numerical simulations with the OpenFOAM libraries in the lib-ICE version of the code. The considered injector configuration is proved to be a promising solution for the realization of a high-pressure diesel cone spray well atomized. In a previous work, it was assessed that spray atomization and penetration are sensible to the injection control parameters, in particular to the injection pressure level, and to the HV (stationary level of the voltage command at the actuator). This could permit the graduation of injection control parameters in order to assure an appropriate control of spray penetration and atomization levels in a dedicated engine combustion chamber. The numerical results show that the code can provide a quite good prevision of the radial tip penetration (TP) but a sensible overestimation of axial TP over all the injection event. CFD simulation describes a rapid breakup process immediately after the fuel discharge providing a finely atomized spray along the whole circumference