Adaptation of a dynamic wrinkling model to an engine configuration

The dynamic model proposed by Charlette et al. represents an interesting alternative to the FSD balance equation to predict the transient growth of a flame kernel. The dynamic wrinkling model coupled to the algebraic Flame Surface Density (FSD) model of Boger et al. is here evaluated for the first time in an internal combustion engine configuration. Preliminary tests enable to evidence practical difficulties when applying the model to this type of complex configuration. Improvements are proposed to adapt the model to the engine configuration. Final simulations are performed on a spark ignition engine configuration, using both the adapted dynamic model and an equilibrium wrinkling formulation. The results are compared to the ones obtained by Robert et al. on the same configuration using the ECFM-LES model solving a FSD balance equation. The dynamic model proves to very well predict out-of-equilibrium values and to account for cycle-to-cycle variabilities, as the model parameter is calculated on the fly. On the contrary, the results obtained using the equilibrium formulation clearly demonstrate that the flame-turbulence equilibrium assumption is not adapted to such configurations.