COMPARTMENT FIRE NEAR-FIELD ENTRAINMENT MEASUREMENTS

A widely accepted consensus on entrainment models for large fires in c ompartments does not yet exist. To obtain further information on such entrainment rates, 20 full-scale, near-field experiments were conducte d. Near-field entrainment occurs when hot layer interface heights are beneath the burner mean flame height so that cold layer entrainment oc curs only near the burner surface. A durable compartment, similar to t he standard fire test compartment, was designed and used in conjunctio n with a 0.61 m x 1.22 m porous surface propane burner to produce comp artment fires with heat release rates from 330 to 980 kW. Entrainment rates of 0.74-0.98 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 off set model and can be used to estimate near-field entrainment rates. An offset for the near-field model of Thomas was also developed. The fir e plume model of Baum and McCaffrey was found to compare favorably wit h the entrainment rates determined here.