Experimental study on flame spread over discrete extruded polystyrene foam with different fuel coverage rates

Abstract

Experimental research on flame spread over discrete extruded polystyrene (XPS) with different fuel coverage rates are conducted in this paper. Flame spread characteristics are measured and discussed. The influence mechanism of the spacing are revealed. A flame vortex is found in the spacing. The change of flame height above the first spacing is divided into three stages. There exists a significantly positive correlation between average flame height and fuel coverage. Flame spread over discrete XPS are not continuous and the discontinuous phenomenon is more significant for lower fuel coverage rate. The average flame spread rate increases with the rising of the fuel coverage rate. The length of the melting zone is positively correlated with the fuel coverage. Compared with the second spacing, it takes more time for the high-temperature zone spreading across the first spacing. The heat flux above the second spacing is the largest while that above the first spacing is the smallest. With the increasing of the fuel coverage, the heat flux transferred to XPS end first rises, then drops, and increase lastly. Keywords: Discrete fuel, Upward flame spread, Extruded polystyrene, Fuel coverage, Temperature distribution, Heat transfer