Unified Analysis for Fire Plumes.
Unified Analysis for Fire Plumes.
(901 K)
Quintiere, J. G.; Grove, B. S.
Combustion Institute, Symposium (International) on
Combustion, 27th. Proceedings. Volume 2. August 2-7,
1998, Boulder, CO, Combustion Institute, Pittsburgh, PA,
2757-2766 pp, 1998.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
combustion; fire plumes; flame radiation; temperature;
velocity; entrainment; flame height
Abstract:
A unified analysis based on an integral approach is
presented for fire plumes involving finite axisymmetric
and rectangular sources. The analysis, using Gaussian
profiles, obtains the best fits to experimental data
found in the literature. Phenomenological constants in
the theory are found to give consistent results in that
coefficients expected to be numerically similar by
theory are found similar among the various data sets.
Thorough reviews of the literature data for line and
rectangular sources are presented and yield consensus
correlations, accordingly. The effect of flame radiation
is explicitly included by a radiation fraction that
proves to be a significant variable, previously
overlooked in experiments. Effective entrainment
coefficients for the far-field noncombusting plume are
found to be 0.09 to 0.10, and for the flame region about
0.22 for the axisymmetric and rectangle cases as long as
D/L > 0.1. For D/L < 0.1, the infinite line gives
nearly double the flame entrainment. Generalized
results are presented for entrainment rate and flame
height in terms of single algebraic equations that span
a wide range of Q* or energy release rate values. For
low Q* fires, the effect of diameter and line width are
important and expressed by the theory but not enough to
address dependence involving Grashof and possibly Froude
number effects near the origin. Laminar results are also
addressed.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899