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Concurrent Turbulent Flame Spread.


pdf icon Concurrent Turbulent Flame Spread. (480 K)
Zhou, L.; Fernandez-Pello, A. C.

NISTIR 4449;

U.S./Japan Government Cooperative Program on Natural Resources (UJNR). Fire Research and Safety. 11th Joint Panel Meeting. October 19-24, 1989, Berkeley, CA, Jason, N. H.; Cramer, D. M., Editor(s)(s), 122-129 pp, 1990.

Sponsor:

National Bureau of Standards, Gaithersburg, MD
National Science Foundation, Washington, DC

Available from:

National Technical Information Service

Keywords:

flame spread rate; turbulence; polymethyl methacrylate; flame length; fire models; flow velocity

Abstract:

The rate of flame spread over the surface of thick PMMA sheets has been measured as a function of the velocity and turbulence intensity of a forced air flow concurrent with the direction of flame propagation. It is shown that the flow turbulence has a strong influence on the flame spread process. For all turbulence intensities, the flame spread rate increases approximately linearly with the flow velocity, although the slope is smaller for larger turbulence intensities. For a given flow velocity, the spread rate decreases as the turbulence intensity is increased, the effect being more pronounced for larger flow velocities. These effects appear to be due to a strong influence of the turbulence intensity on the flame length, which decreases as the turbulence intensity is increased, thus reducing the net heat flux from the flame to the unburnt combustible. The results are significant since the prediciton of the flame length and spread rate as a function of the problem parameters are important factors in the development of room fire models.