Autoignition of n-heptane in a turbulent co-flowing jet

Abstract

N-heptane autoignition in turbulent co-flowing jets with preheated air is studied using the one-dimensional turbulence (ODT) model. The simulations are designed to investigate the effects of molecular and turbulent transports on the process of autoignition. Both homogeneous and jet configuration simulations are carried out. The jet configurations are implemented at different jet inlet Reynolds numbers and for two air preheat conditions. Statistics for the cases considered show that, while the onset of autoignition may be delayed by turbulence, the eventual evolution of the volumetric heat release rate indicates that turbulence enhances the post-ignition stages. Since different regions of the mixture can have different ignition delays and may be characterized by one- or two-stage ignition, the autoignition process can be accelerated by ignition kernel propagation or the role of heat dissipation may be reduced through the prevalence of one-stage and two-stage ignitions in different regions of the mixture.