Experimental investigation on the effect of ambient pressure on entrainment coefficient of pool fires

Abstract

Previous experiments at high-altitude environments have indicated that the ambient pressure has an effect on the entrainment coefficient, which further affects the axial temperature profile of a fire plume. However, their substantial relationship remains unclear as only a limited number of tests have been conducted. In this work, a reduced pressure compartment is employed to mimic the sequential low-pressure environments (40–101 kPa) for small-scale pool fires with diameters of 6, 8, and 10 cm, in order to determine the entrainment coefficient at different pressures based on the measurements of axial temperature profile. It is revealed that the entrainment coefficient relative to that at atmospheric pressure has a linear relationship with ambient pressure, which is validated in the pressure range of 40–101 kPa. By taking this relationship into consideration, all the plume temperature data can be correlated non-dimensionally with z-zo/D.