泡沫材料在狭缝空间垂直火蔓延的数值模拟

保温材料的火蔓延特性对建筑防火有重要意义,而其在狭缝等特殊空间结构中的燃烧特性还缺乏深入研究.本文采用CFD模拟技术和并行计算手段对狭缝空间中泡沫材料的竖直火蔓延特性进行了分析研究.计算发现在狭缝宽度为5 -6 cm时,由于侧向补风增强,导致狭缝内存在规则的大尺度涡旋结构.涡旋将火焰向两侧拉扯,而且涡旋强度可以增强狭缝内火蔓延速度.相对开放空间的情况,在狭缝空间中泡沫材料的火焰高度随线热释放速率强度的增加较慢,并且存在最小热释放速率强度.当热释放速率强度小于一定值时,火焰将会熄灭.

Numerical study of polyurethane foam fire between narrow vertical parallel walls

Polyurethane foam has a number of practical uses as building decoration materials and insulating materials.The study of the polyurethane foam in some special building structures is deficiency and imperative.The CFD technology and parallel computing method are used to simulate the fire propagation character of the polyurethane foam between vertical parallel surfaces.The results indicate that the flame will be split in two because of the strong side vortexes which generate when the fresh air supply come from the side,when the wall spacing is 6cm or 5cm.And the vortexes can enhance the fire spread velocity when the width of the surfaces is 6cm.The flame height increases more slowly with the heat release rate per unit width contrast with the flame in opening space,although the function foam is similar.The new formula improved in this paper include a heat release rate correction term which it is no included in the old one.At the same time,there is a minimum heat release rate value below which the fire can’t sustain.