Extinction of nonpremixed flames with halogenated fire suppressants

Conference · Mon Oct 31 23:00:00 EST 1994 · Combustion and Flame; (United States)

OSTI ID:6794766

Hamins, A ^[1]; Trees, D; Seshadri, K ^[2]; Chelliah, H K ^[3]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Building and Fire Research Lab.
2. Univ. of California, San Diego, La Jolla, CA (United States). Center for Energy and Combustion Research
3. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical Aerospace and Nuclear Engineering

An experimental, analytical, and numerical study was performed to elucidate the influence of eleven gaseous agents, considered to be substitutes for CF[sub 3]Br, on the structure and critical conditions of extinction of diffusion flames burning liquid hydrocarbon fuels. The effectiveness of these agents in quenching flames was compared to those of CF[sub 3]Br and an inert diluent such as nitrogen. Experiments were performed on diffusion flames stabilized in the counter flowing as well as in the coflowing configuration. The fuels tested were heptane in the counter flowing configuration, and heptane, the jet fuels JP-8, and JP-5, and hydraulic fluids (military specifications 5606 and 83282) in the coflowing configuration. The oxidizing gas was a mixture of air and the agent. On a mass and mole basis CF[sub 3]Br was found to be most effective in quenching the flames and the mass-based effectiveness of the other eleven agents was found to be nearly the same as that of nitrogen. Experimental results were interpreted using one-step, activation-energy asymptotic theories and the results were used to provide a rough indication of the thermal and chemical influence of these agents on the flame structure. To understanding some detail the influence of CF[sub 3]Br on the structure and mechanisms of extinction of the flame, numerical calculations using detailed chemistry were performed. The calculated structure of counterflow heptane-air diffusion flames inhibited with CF[sub 3]Br was found to consist of three distinct zones including a CF[sub 3]Br consumption zone which appears to act as a sink for radicals. The calculated values of the critical conditions of extinction of counterflow heptane-air diffusion flames inhibited with CF[sub 3]Br were found to agree fairly well with measurements. The study suggests the need for refinement of the inhibition chemistry.

• OSTI ID: 6794766
• Report Number(s): CONF-940711--
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 99:2; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500 -- Engineering-- Materials Testing
54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR POLLUTION ABATEMENT
BROMINATED ALIPHATIC HYDROCARBONS
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
EVALUATION
FIRE EXTINGUISHERS
FIRE FIGHTING
FLUORINATED ALIPHATIC HYDROCARBONS
FUELS
HALOGENATED ALIPHATIC HYDROCARBONS
INHIBITION
JET ENGINE FUELS
KINETICS
LAYERS
LIQUID FUELS
MATERIAL SUBSTITUTION
MATERIALS TESTING
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OZONE LAYER
POLLUTION ABATEMENT
REACTION KINETICS
TESTING