Effect Of Fuel Sootiness On The Heat Fluxes To The Walls In Enclosure Fires

Abstract

Even though considerable work has been performed regarding gas temperatures and burning rates in enclosures, scant information is available for the heat fluxes and their distributions on the walls of an enclosure. These heat fluxes are necessary input for determining the thermal response and performance of the wall materials and especially glazing. The heat fluxes on the wall of an experimental enclosure were deduced from the temperatures in several thermally thin small steel plates (25.4 mm x 25.4 mm x 3 mm thick) and in the insulation surrounding the steel plates. In addition, the mass loss rate and gas temperatures near these heat flux gauges were measured. The experimental enclosure was the 1/3 linear scale of the ISO room corner test having six openings and three square-pans of variable size burning Methanol, IMS (Industrial Methylated Spirits) and Toluene at the corner and in the center of the enclosure. By choosing fuels with an increased degree of sootiness it was found that the heat fluxes do not depend only on the gas temperature, as claimed before for heat fluxes on the floor, but also on the magnitude of the heat release rate and the fuel sootiness. Moreover, comparison of the heat fluxes for methanol, IMS and toluene allow the separation of convective from radiative heat fluxes owing to hot gases (and the enclosure walls) and from the radiative heat fluxes from the fire plume.

Experimental investigation on burning characteristics of diesel pool fires in naturally ventilated compartment

“…However, variation was found to be more above 0.6 m pool diameter. This is because, for larger fires in overventilated conditions, gas temperature at the upper layer was higher (see Figure 14), which leads to a significant increase in heat flux due to the convection and radiation heat transfer applied to the upper wall surface 50 …”

Effects of Time to Unactuate Air Conditioning on Fire Growth

“…Whether the fire growth is enhanced or suppressed depends on which factor plays the main role. To further understand fire growth in confined spaces affected by ventilation, many previous studies have investigated the heat release rate (HRR) of fire sources [18][19][20][21][22][23][24][25], the fuel mass loss rate [19,[26][27][28], the burning rate [13,17,29], the temperature [13,18,22,23,25,[28][29][30][31][32] and visibility [30,32] of the confined space, the thickness of the hot smoke layer [19,25,27,31], the heat fluxes on the floor [28] and the time to flashover (t fo ) [18,32]. A complete description of these studies can be found in Wang and Tsai [32].…”

“…The effects of both natural and mechanical ventilation on fire growth must be addressed. [22] 3 × 3.6 × 2.3M erci and Maele [23] 3 × 3.6 × 2.3Ľ assus et al [24] 2 × 2 × 2Ǧ omez et al [25] 32 × 17 × 8ˇŤ homas and Bennetts [26] 1.5 × 0.6 × 0.3P ierce and Moss [27] 1.8 × 1.2 × 1.2Ť ofilo et al [28] 1.2 × 0.8 × 0.8Ǩ umar and Naveen [29] 2.79 × 2.24 × 1.62Ȟ uang et al [30] 22.5 × 16 × 12Š u et al [31] 2.3 ×1.3 × 2.5ˇW ang and Tsai [32] 3.8 × 3.8 × 2.4ˇŠ u et al [31] utilized the Fire Dynamics Simulator (FDS) to analyze the position of air inlet and air exhaust in small vestibules of high-rise buildings. In their fire simulation scenario, the front door and rear door of the confined space were open, and the smoke exhaust and air supply rates were both 4.0 m 3 /s in the confined space.…”