An Investigation of Soot Evolution in High-pressure Spray Combustion

Morphological changes in soot emitted from combustion devices have a tremendous impact on the evolution of soot in the atmosphere. The current study focuses on understanding the physio-chemical phenomena leading to various morphological changes in soot from combustion devices. The primary objective of this study is to look at qualitative trends in soot particle statistics during high-pressure spray combustion of n-dodecane under engine-relevant conditions (Spray A). The simulations were performed with detailed chemistry in an unsteady Reynolds-averaged framework. A fully-coupled method of moments-based soot model and Monte Carlo radiation solver with line-by-line spectral data are also used to capture soot and radiation in the simulations. Simulations were validated using the experimental data provided by engine combustion network (ECN). Three different exhaust gas recirculation (EGR) configurations are investigated and it was found that the amount of soot, as well as mean soot diameter, increases with O2% in EGR. The diameter distribution was found to widen with increasing O2%. It was also found that the probability distribution of soot diameter evolves to a narrow unimodal shape from its initial bimodal shape as the time progresses