Application of the Shell ignition model and comparison with spectroscopic measurements of a high swirl Diesel combustion

comparison between experimental data and results of an integrated numerical model based on the KIVA-3 code is performed with the aim to highlight the fuel ignition process in a high-swirl divided-chamber Disesel system. Spectral extinction and flame intensity measurements from UV to visible are taken in an optically accessible apparatus. Low and high temperature kinetics are numerically simulated by switching from a multiple-steps to a one-step model at a cut-off value of temperature. Kineticsconstants are tuned according to the measured data. The influence of spray formation and charge dynamics on the ignition process is fully taken into account. OH radicals are individuated in correspondence of the pressure at start of ignition. Theirdistribution is compared to that of the generic species involved in the model and an explanation of the fole played by these last is given.