Flame height and temperature profile of window ejected thermal plume from compartment fire without facade wall

This paper investigates experimentally the flame height and temperature profile of window ejected thermal plume from compartment fire without facade wall. The previous works and correlations on these characteristics of such thermal plume mainly concern the condition with a facade wall, where the air entrainment of the thermal plume from the side of the facade wall is restricted. However, such entrainment constraint effect does not exist when the fire occurs at the top floor of the building noting that there is no facade above the top floor, for which scenario the flame height and temperature profile of the thermal plume characteristics have not been quantified in the literature. In this work, comprehensive experiments were carried out by employing a reduced-scale model (1:8), consisting of a 0.4 m cubic fire compartment with six different window openings corresponding to various ventilation factors (AH). A propane square porous burner was set as fire source with various fuel mass flow meters and hence heat release rate. All the tests were designed as un-ventilated condition that stable flame was observed outside the window. The flame height outside the window was recorded through a CCD camera from the side view. The temperature profiles of the ejected fire plume outside the window were measured by the thermocouple arrays (7 rows, 7 columns) located above the top of the compartment. These measured quantities without the facade wall were compared from those with a facade wall. Results showed that the flame height can be still well correlated non-dimensionally by the excess fuel heat release rate and the characteristic length scale (ℓ1=(AH)2/5) of the window. However, the flame height with a facade wall was higher, being 1.31 times of those without a facade wall. This difference was physically quantified by the air entrainment change due to constraint effect from the facade wall. The radial temperature profile in the ejected thermal fire plume at various height can be globally represented by the Gaussian function (Tz,x−T∞Tz,max−T∞=e[−β(x−xmFWHM)2]) with and without facade wall, where the value of β was found to be 2ln2. These quantifications and correlations on window-ejected thermal plume characteristics without a facade wall, providing a significant supplementary over previous works focusing on condition with the facade wall, will be an important addition for the estimation of such thermal plume characteristics and its thermal impacts. This work, providing experimental data and correlations on window ejected thermal plume characteristics from compartment fire at the top level of the building without the effect of facade wall, will be an important supplementary over previous knowledge focusing on the scenario with the effect of facade wall.