A Kinetic Mechanism for CF₃I Inhibition of Methane–Air Flames

The influence of CF₃I on the burning velocity of methane–air flame is experimentally and numerically studied. Experimental results demonstrate that the inhibition effectiveness of CF₃I is very close to that of CF₃Br. A detailed kinetic model of flame inhibition by CF₃I is presented, based on an updated version of a previous model. The kinetic model contains 1072 reactions with 115 species including 10 iodine-containing species. Modeling results demonstrate good agreement with experimental data, and both experiments and calculations show that CF₃I is only slightly less effective at reducing the burning velocity than CF₃Br. The flame structure predicted from numerical simulations is analyzed and shows that main reactions of the inhibition cycle of CF₃I are as follows: H+ HI = H₂ + I; H + I + M = HI+M; I + I + M = I₂ + M; H+ I₂ = HI+I; I+ CH₃ + M = CH₃I+M; H+ CH₃I = CH₃+ HI; I+ HCO = HI+CO; HI+OH = H₂O+I and O+ HI = I+ OH.