Compartment Fire Near-Field Entrainment Measurements.
Compartment Fire Near-Field Entrainment Measurements.
(1928 K)
Dembsey, N. A.; Pagni, P. J.; Williamson, R. B.
Fire Safety Journal, Vol. 24, No. 4, 383-419, 1995.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
compartment fires; entrainment; experiments; data
analysis; mass flow; flow rate; vents; flame height;
fire plumes
Abstract:
A widely accepted consensus on entrainment models for
large fires in compartments does not yet exist. To
obtain further information on such entrainment rates, 20
full-scale, near-field experiments were conducted.
Near-field entrainment occurs when hot layer interface
heights are beneath the burner mean flame height so that
cold layer entrainment occurs only near the burner
surface. A durable compartment, similar to the standard
fire test compartment, was designed and used in
conjunction with a 0DT61 m x 1DT22 m porous surface
propane burner to produce compartment fires with heat
release rates from 330 to 980 kW. Entrainment rates of
0DT74-0DT98 kg/s were calculated from temperature
measurements made within the compartment and in the
doorway. The entrainment rates determined here were
correlated with values from the literature. This
correlation led to two curve fits which modify Zukoski's
far-field offset model and can be used to estimate
near-field entrainment rates. An offset for the
near-field model of Thomas was also developed. The fire
plume model of Baum and McCaffrey was found to compare
favorably with the entrainment rates determined here.
