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Compartment Fire Near-Field Entrainment Measurements.


pdf icon 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.