Inhibition of premixed methane-air flames by fluoromethanes

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Combustion and Flame

DOI:https://doi.org/10.1016/0010-2180(95)00152-2· OSTI ID:215665

Linteris, G T ^[1]; Truett, L ^[2]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States)
2. WL/FIVS, Wright-Patterson AFB, OH (United States)

This paper presents the first calculations and measurements of the burning velocity of premixed hydrocarbon flames inhibited by the three one-carbon fluorinated species CH{sub 2}F{sub 2}, CF{sub 3}H, and CF{sub 4}. Studying their behavior in methane flames provides an important first step towards understanding the suppression mechanism of hydrocarbon fires by fluorinated compounds. The burning velocity of premixed methane-air flames 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, {phi}. The measured burning velocity reduction caused by addition of the inhibitor is compared with that predicted by numerical solution of the species and energy conservation equations employing a detailed chemical kinetic mechanism recently developed at NIST. Even in this first test of the kinetic mechanism on inhibited hydrocarbon flames, the numerically predicted burning velocity reductions for methane-air flames with values of {phi} of 0.9, 1.0, and 1.1 and inhibitor mole fractions in the unburned gases up to 0.08, are in excellent agreement for CH{sub 2}F{sub 2} and CF{sub 4} and within 35% for CF{sub 3}H. The numerical results indicate that the agents CF{sub 3}H and CH{sub 2}F{sub 2} are totally consumed in the flame and the burning velocity is reduced primarily by a reduction in the H-atom concentration through reactions leading to HF formation. In contrast, only about 10% of the CF{sub 4} is consumed and it reduces the burning velocity primarily by lowering the final temperature of the burned gases.

• OSTI ID: 215665
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 105; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
CARBON TETRAFLUORIDE
CATALYTIC EFFECTS
COMBUSTION KINETICS
CONCENTRATION RATIO
FIRE EXTINGUISHERS
FLAME PROPAGATION
FLUORINATED ALIPHATIC HYDROCARBONS
FUEL-AIR RATIO
GAS BURNERS
HYDROFLUORIC ACID
INHIBITION
MATHEMATICAL MODELS
METHANE
PERFORMANCE