Fire Safety Science Digital Archive

This paper updated the two existing flame inhibition mechanisms for C3HF7 (FM-200TM) of Sanogo et al. and Williams et al. using the sensitivity analysis of the burning velocity as the criterion. GRI Mech 3.0 was deployed to model the combustion of methane. The results of the modified mechanisms were then compared with the published experimental measurements of (i) flame structure for CH4/O2/Ar premixed flames inhibited by 1.0% C3HF7 as derived from the molecular beam-mass spectrometry (MBMS) data and (ii) low pressure (10 torr) stoichiometric CH4/O2 premixed flames inhibited by 4.0% C3HF7 as obtained from experiments involving the laser-induced fluorescence (LIF). The numerical calculations were performed with the aid of PREMIX computer code for burner stabilised (flame structure) and freely propagating (burning velocity) flames. The inlet boundary condition was modified to allow a direct specification of the inlet composition for all species. The results of the computation indicate that both modified mechanisms yield similar burning velocities and similar concentration profiles of major species. This means that, the simpler mechanism of Sanogo et al., as modified in the present work, can be used in scoping studies where a large number of cases need to be run rapidly or to obtain an interim solution for further optimisation with the modified mechanism of Williams et al.