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Fluid Dynamics of Fire Whirls: An Inviscid Model.


pdf icon Fluid Dynamics of Fire Whirls: An Inviscid Model. (1371 K)
Battaglia, F.; Rehm, R. G.; Baum, H. R.

NISTIR 6427; 18 p. February 2000.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB2001-104051

Keywords:

fire whirls; fluid dynamics; methodology; fire plumes; entrainment; combustion; buoyant plumes; equations

Abstract:

Whirling fire plumes are known to increase the danger of naturally occurring or post-disaster fires. In order for a fire whirl to exist, there must be an organized source of angular momentum to produce the large swirl velocities as air is entrained into the fire plume. These vorticity-driven fires occur over a large range of length and velocity scales, and significantly alter the entrainment and combustion dynamics. A new model that incorporates angular rotation and neglects dissipation is derived for a buoyant plume; the result is a form of the steady state Euler equations. Included is a general solution for large density and temperature variations. Results that identify the mechanisms and their effects on the creation of a fire whirl are presented.