Measurements and Prediction of Fire Induced Flow Field.
Measurements and Prediction of Fire Induced Flow Field.
(111 K)
Zhou, X. C.; Gore, J. P.; Baum, H. R.
NISTIR 5904; October 1996.
National Institute of Standards and Technology. Annual
Conference on Fire Research: Book of Abstracts.
October 28-31, 1996, Gaithersburg, MD, 77-78 pp, 1996.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Available from:
National Technical Information Service
Order number: PB97-153514
Keywords:
fire research; fire science; flow fields; entrainment;
pool fires; methanol; heptane; toluene
Abstract:
Motivated by the various application of entrainment rate
correlations in fire research and the large uncertainty
in the efficacy of existing correlations and
experimental data, the first particle Imaging
Velocimetry (PIV) based measurements of fire induced
flow field around pool fires burning methanol, heptane
and toluene were obtained. Air entrainment rates for 15
cm and 30 cm pool fires burning the three different
fuels were calculated based on the mean velocity field.
The entrainment data for the six fires could be
correlated well using the fire Froude number, defined in
Ref. 1 as the nondimensional parameter. A kinematic
approach for the prediction of the fire induced flow
field, following Ref. 2, was extended to the present
fires. The driving processes for the entrainment flow,
namely the volumetric heat release and the baroclinic
vorticity generation, were evaluated based on
correlations of buoyant diffusion flame structure in the
literature. The predicted entrainment velocities were
substantially higher than the measurements but were in
qualitative agreement with the data. Based on this, the
heat release rate and vorticity correlations used in the
analysis were corrected by using a smaller radius for
the 1/e point in the elocity profile. The modified
predictions were in better agreement with the
experimental data. Therefore, further evaluation of the
kinematic approach with proper heat release rate and
vorticity distributions is warranted.
