Numerical study of the impact of global mechanisms in LES of propane pool fire using the EDC - finite-rate chemistry approach

Abstract

Large eddy simulations of propane pool fires are presented considering the eddy dissipation concept (EDC) with finite-rate chemistry. Two global chemistry mechanisms (with 2-step reactions) are evaluated in different grid resolutions. The main focus is on the capability of EDC to accurately capture the flame dynamics and key parameters such as temperature, velocity and heat release rate. In addition, the performance of the global mechanisms in predicting species yield, particularly carbon monoxide (CO), is evaluated. Supplementing the LES results, an analysis of 1D counterflow diffusion flames is also presented. The results reveal minimal differences in the predicted temperature and flow field between the two mechanisms. A strong grid dependency is observed for the coarser grid sizes, and unsatisfactory behavior near the burner highlights some EDC limitations. Although the heat release rates are captured reasonably well, there are significant discrepancies in the CO predictions and the resulting flow field when compared against the experiments. These findings reveal that these mechanisms are not suitable for predicting minor species in fires and that the EDC formulation for fire scenarios could be improved.