Suppression of high-speed C{sub 2}H{sub 4}/air flames with C{sub 1}-halocarbons
- National Inst. of Standards and Technology, Gaithersburg, MD (United States). Building and Fire Research Lab.
Experimental investigation of the effect of the presence of five C{sub 1}-halocarbons (CF{sub 4}, CHF{sub 3}, CF{sub 3}I, CHF{sub 2}Cl, and CF{sub 3}Br) on the suppression of premixed high-speed turbulent flames and quasi detonations have been carried out in a 7.5-m long, 50-mm diameter tube. Lean and stoichiometric C{sub 2}H{sub 4}/air mixtures in the absence of any halocarbon, initially at 100 kPa and 295 K, constitute the reference states. A primary objective of the work has been to determine the relative suppression efficiencies of different agents under highly dynamic situations, without the undue influence of either the ignition event or the mixing of the agent into the flame front. This was accomplished by generating a highly turbulent flame/quasi detonation in the driver section, which contained no suppressant, followed by measurements of the velocity and pressure ratio as the wave front entered the test section of the tube, which contained suppressant premixed with the same fuel/air combination. A turbulence generator in the form of a spiral obstruction was used in the tube to broaden the gas-dynamic condition attainable by the flame. Flame and shock wave velocities up to 1300 m/s, pressure ratios across the shock fronts over 26:1, and shock wave/flame spacings of the order of 10 cm were measured with piezoelectric pressure transducers and fast photodiodes. The experimental facility was successfully employed to clearly discriminate among the dynamic characteristics of the five compounds, revealing behavior distinct from what was observed in companion studies using atmospheric nonpremixed flames. The suppression process is strongly influenced by the concentration of an agent, the structure and composition of an agent molecule, and the composition of the combustible mixture itself.
- OSTI ID:
- 93301
- Report Number(s):
- CONF-940711-; TRN: IM9537%%345
- Resource Relation:
- Conference: 25. international symposium on combustion, Irvine, CA (United States), 31 Jul - 5 Aug 1994; Other Information: PBD: 1994; Related Information: Is Part Of Twenty-fifth symposium (international) on combustion; PB: 1838 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
54 ENVIRONMENTAL SCIENCES
ETHYLENE
COMBUSTION
CARBON TETRAFLUORIDE
PERFORMANCE TESTING
FLUOROFORM
CHLOROFLUOROCARBONS
FIRE EXTINGUISHERS
BROMINATED ALIPHATIC HYDROCARBONS
IODINATED ALIPHATIC HYDROCARBONS
FLAMES
INHIBITION
FLAME PROPAGATION
OZONE LAYER
MATERIAL SUBSTITUTION
TEST FACILITIES
EXPERIMENTAL DATA