CO modelling of premixed head-on quenching flame in the context of Large-Eddy Simulation

The capability of LES sub-grid scale modelling approaches to determine near-wall CO concentration during flame-wall interaction (FWI) is investigated through the analysis of fully-resolved simulations of premixed flame head-on quenching. Pre-tabulated lookup tables for CO based on the reduced temperature and a progress variable are shown to be a promising approach for non-adiabatic CO concentration modelling. Two commonly used generalised Flame Surface Density (FSD) models are also tested in this a priori study. It is shown that both models underpredict CO concentration during quenching. A significant increase of the displacement speed as well as a large variation of this quantity across different iso-values of the progress variable are observed during quenching, which are not captured by the FSD models. The results suggest that in the context of FSD modelling for FWI, the entire flame front displacement speed term, ρS_d|∇c|‾ needs to be modelled, rather than just the wrinkling factor.