Inhibition of Premixed Methane-Air Flames by Halon Alternatives.
Inhibition of Premixed Methane-Air Flames by Halon
Linteris, G. T.; Truett, L.
National Institute of Standards and Technology (NIST)
and Society of Fire Protection Engineers (SFPE).
International Conference on Fire Research and
Engineering (ICFRE). Proceedings. September 10-15,
1995, Orlando, FL, SFPE, Boston, MA, Lund, D. P.;
Angell, E. A., Editor(s)(s), 153-158 pp, 1995.
Sponsor:Air Force, Washington, DC
fire research; halon alternatives; chemical inhibition;
flame chemistry; flame models; flame retardants; flame
Halogenated hydrocarbons are effective and widely used
as fire suppressants. Because of their suspected
destruction of stratospheric ozone, however, the
production of these agents, the most popular being halon
1301 (CF3Br), has been discontinued. There exists a
need to develop alternatives to the halons, to establish
the relative effectiveness of alternative inhibitors,
and to understand the mechanism of inhibition of the new
agents. The agents which are currently being considered
are most fluorinated alkanes. This article describes
the first measurements of the reduction in burning rate
of premixed methane-air flames inhibited by the
two-carbon fluorinated species C2F6, C2HF5, C2H2F4 and
the three-carbon species C3F8 and C3HF7, all of which
are being considered as replacements to CF3Br. The
burning rate of premixed methane-air flames stabilized
on a Mache-Hebra nozzle burner is determined using the
total area method from a schlieren image of the flame.
The inhibitors are tested over a range of concentration
and fuel-air equivalence ratio, theta. The measured
burning rate reduction caused by addition of the
inhibitor is compared (for the two-carbon species) with
that predicted by numerical solution of the mass,
species, and energy conservation equations employing a
detailed chemical kinetic mechanism recently developed
at the National Institute of Standards and Technology