Numerical study of the impact of the EDC formulation and finite-rate chemistry mechanisms in CFD simulations of fire plumes

Abstract

CFD simulations are presented for an in-depth study on different formulations (including implementation details) of the Eddy Dissipation Concept (EDC) turbulent combustion model, with infinitely fast chemistry as well as finite-rate chemistry with different reaction mechanisms. A turbulent line burner and a gaseous pool fire are chosen as first step in an extensive validation campaign for large eddy simulations of this kind, performed with OpenFOAM v1912. Artificial flame anchoring is necessary to establish a burning flame with finite-rate chemistry. Differences in mean temperatures, and the resulting flow fields, as obtained with the different formulations of the EDC combustion model, are explained by the impact of the reaction rates. CO is discussed as the most important of minor species as well. It is demonstrated that both the formulation of EDC and the choice of the chemistry mechanism can have a significant impact when the CFD mesh is not sufficiently fine, even though the flames studied are unsuppressed. This can lead to significant deviations from experimental data. This is a point of attention for future work, focusing on extinction and re-ignition phenomena.