Study on the influence of enclosed vertical channels on downward flame spread over XPS thermal insulation materials

Abstract

In this paper, the small-scale combustion experiments are carried out in combination with theoretical analysis to study the influence of length-width ratio (α) of enclosed vertical channel on the downward flame spread of XPS insulation material attaching to the wall. The experimental results show that the average flame height firstly increases and then decreases with the increase of α. The average temperature and maximum temperature of the curtain wall surface decrease with the increase of α, which is mainly caused by the heat loss in the passageway. Through theoretical analysis, the total heat flow received by the preheating zone is mainly controlled by heat transfer of flame convection, and its change trend is basically consistent with that of average flame spread velocity, namely, firstly increasing and then decreasing with the increase of α. Keywords: Vertical channels, Downward flame spread, Extruded polystyrene, Length-width ratio, Flame height, Heat transfer