Diesel Flame Extinction at Low Oxygen Concentrations: Importance of Kinetics Modeling

摘要

Extinction scalar dissipation rate calculations are performed for laminar diffusion flamelets at oxygen molar concentrations ranging from 21% to 10% at conditions corresponding to those in a Diesel engine. N-heptane is used as a surrogate for Diesel fuel and its oxidation chemistry modeled using two reduced mechanisms; a 37-species, 56-step mechanism and a 159-species, 1540-step mechanism. For lower O{sub}2 concentrations (< 15%), the predictions with the two mechanisms are significantly different, with the more detailed mechanism yielding higher values. Reaction-pathway analysis indicates that the difference in extinction predictions is related to different reaction rate coefficient parameters and the presence of additional pathways in the 159-species mechanism.