Inhibition Effectiveness of Halogenated Compounds.
Inhibition Effectiveness of Halogenated Compounds.
(1112 K)
Noto, T.; Babushok, V. I.; Hamins, A.; Tsang, W.
Combustion and Flame, Vol. 112, No. 1/2, 147-160,
January 1998.
Keywords:
fire research; halogenated compounds; laminar flames;
premixed flames; burning velocity; additives;
inhibitors; flame retardants; saturation
Abstract:
A numerical study of the inhibition efficiency of
halogenated compounds was carried out for C1-C2
hydrocarbon-air laminar premixed flames. The inhibition
efficiency of CF3Br, CF3I, CF3H, C2HF, C2F6, and CF4
additives was interpreted using an additive group
method. In agreement with measurements, the calculated
burning velocity decreased exponentially with increasing
additive concentration over a wide concentration range.
The inhibition parameter proposed by Fristrom and Sawyer
indicating inhibition efficiency was modified to take
into account the expoential dependence of burning
velocity on inhibitor concentration. The inhibition
indices for halogen atoms and groups important in the
inhibition process were determined for stoichiometric
conditions. The physical and chemical effects of the
additives were studied. With increasing additive
concentration, the chemical influence of an inhibitor
saturates and the physical influence increases.
Therefore, use of a composite inhibitor composed of a
mixture of an effective chemical inhibitor with a high
heat capacity diluent may be beneficial. The
contribution of physical and chemical components on
inhibitor influence are estimated near extinction. A
procedure for determinaiton of a regeneration
coefficient, which indicates an effective number of
catalytic cycles involving inhibitor during the
combustion process, is suggested. The regeneration
coefficient of HBr in stoichiometric methane-air flame
with 1% CF3Br added is approximately 7.
