- Author
-
Gmurczyk, G. W.
|
Grosshandler, W. L.
- Title
- Suppression of High-Speed C₂H₄/Air Flames With C₁-Halocarbons.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Book or Conf
- Combustion Institute. Symposium (International) on Combustion, 25th. Proceedings. Abstracts of Symposium Papers. Session 06-K: Fire Suppression. July 31-August 5, 1994,
Combustion Institute, Pittsburgh, PA,
Irvine, CA,
61 p.,
1994
- Keywords
-
combustion
|
fire suppression
|
turbulent flames
|
premixed flames
|
predictive models
|
dynamic characteristics
- Identifiers
- halocarbons
- Abstract
- Experimental investigations of the effect of the presence of five C₁-Halocarbons (CF₄, CHF₃, CF₃I, CHF₂Cl and CF₃Br) 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 C₂H₄/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 conditions 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 piezo-electric pressure tranducers 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 non-premixed 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.