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The main objective of the present paper is the application of a detailed kinetic model to study diesel combustion in an optical accessible engine equipped with a common rail injection system. Three different injection schedules made of one to three consecutive injections are considered from both the numerical and the experimental point of view. The numerical model is assessed in such a way to assure its portability with respect to changing injection strategies. The employed detailed kinetic mechanism consists of 305 reactions involving 70 species and is included in the KIVA-3V code. The considered fuel has the liquid phase properties of the diesel oil, the vapor phase properties of C14H28. It is subsequently decomposed into n-heptane and toluene. The chemical solver is based on the use of the reference species technique and on the Partially Stirred Reactor (PaSR) hypothesis. These allow maintaining the computational cost within acceptable limits.

The work analyses, from both an experimental and a numerical point of view, the impingement of a spray generated from a GDI injector on a hot solid wall. The temperature of the surface is identified as an important parameter affecting the outcome after impact. A gasoline spray issuing from a customized single-hole injector is characterized in a quiescent optically-accessible vessel as it impacts on an aluminum plate placed at 22.5 mm from the injector tip. Optical investigations are carried out at atmospheric back-pressure by a direct schlieren optical set-up using a LED as light source. A synchronized C-Mos high-speed camera captures cycle-resolved images of the evolving impact. The spatial and temporal evolution of the liquid and vapor phases are derived. They serve to define a data base to be used for the validation of a properly formulated 3D CFD model suitable to describe the impact of the fuel on the piston head in a real engine.