Self-Preserving Buoyant Turbulent Plumes.
Self-Preserving Buoyant Turbulent Plumes.
(808 K)
Faeth, G. M.
NISTIR 6030; June 1997.
U.S./Japan Government Cooperative Program on Natural
Resources (UJNR). Fire Research and Safety. 13th Joint
Panel Meeting. Volume 1. March 13-20, 1996,
Gaithersburg, MD, Beall, K. A., Editor(s), 275-284 pp,
1997.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Available from:
National Technical Information Service
Order number: PB97-184204
Keywords:
fire safety; fire research; buoyant plumes; equations
Abstract:
An experimental study of round buoyant turbulent plumes
is described, emphasizing conditions where the flow has
lost source momentum and other source distrubances, and
has become self preserving. Plume conditions were
simulated using dense gas sources in a still and
unstratified air environment. Mean and fluctuating
mixture fractions and velocities were measured using
laser-induced fluorescence and laser velocimetry,
respectively. The present measurements extended farther
from the source than most earlier work (up to 151 source
diameters and 43 Morton length scales) and show that
self-preserving plumes are narrower and have large mean
properties near the axis than previously thoght.
Although contemporary turbulence models yield reasonably
good predictions of mean properties in the
self-preserving region, there are difficulties with many
of the approximations concerning turbulence properties;
this raises questions about the potential effectiveness
of these models for predicting the properties of the
complex buoyant turbulent flows that are encountered in
practical fire environments.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899