A spark ignition model for large eddy simulation based on an FSD transport equation (ISSIM-LES)

The aim of this study is to develop a spark ignition model for LES of aero-engines and piston engines. This model called ISSIM-LES (Imposed Stretch Spark Ignition Model) is based on the same electrical circuit description as AKTIM [1] and flame kernel initialisation as AKTIMeuler [2]. The main difference with AKTIMeuler resides in the description of the flame kernel growth which is now solely modelled thanks to a modified flame surface density (FSD) equation. This new model allows multi-ignition description without any ad hoc adaptation since the different ignitions are directly controlled by the flame surface density (FSD) equation, which is modified during early flame ignition. This model is applied to flame kernel growth in isotropic homogeneous turbulence in a fan-stirred bomb for various equivalence ratios and turbulence levels [3]. Discussions and analysis focus on the sensitivity of the results to the transition from the SGS ignition kernel to the fully resolved turbulent flame, on the comparison between ISSIM-LES and AKTIMeuler, on the effect of stretch on the flame kernel growth and finally, on the sensitivity of the early flame kernel development to the initial turbulent velocity field. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.