高层建筑典型外墙保温材料火蔓延特性数值模拟研究

有机保温材料被广泛应用于高层建筑外墙保温体系的同时,也可能增加高层建筑的火灾风险。本文通过计算机模拟,着重研究了保温材料之一的聚苯乙烯泡沫塑料（EPS）的火蔓延速率、失重速率及温度场分布等特性。研究结果发现：发生火灾后,外墙保温材料可以在很短的时间内自下而上蔓延至整个材料表面,并有表皮着火的现象。在火焰到达材料顶部之前,向上火蔓延占主导地位,材料中部区域明显燃烧脱落,火焰在材料两端上部继续燃烧,有向下加速蔓延的趋势;之后,火焰沿着材料中部内侧向下剧烈燃烧,材料呈V字型燃烧直至熄灭。在高层建筑外墙外保温材料火蔓延中,不同着火点情况下的燃烧速率随时间变化的趋势相似,且会形成两个波峰。

Simulation of Fire Spread of Typical External Wall Insulation Materials in High-rise Building

Organic insulation materials are widely used in the external wall insulation system of high-rise buildings,but it also increases the risk of external wall fire.This paper,based on computer simulation,focuses attention mainly on the fire spread rate,mass loss rate,temperature distribution and other characteristics of one of the insulation materials Expanded Polystyrene（EPS）.The study found that after the ignition of the external insulation material,in a very short period of time,fire spreads to the entire surface from bottom up,and has a feature of skin burning.Upward fire spread dominates before it reached the top of the material.The central region of the material was remarkably burned off.While the upper ends of the material continued to burn,accelerating the trend of downwards spread,then fire spreads downwards intensely along the middle of inside material and materials burned into a V-shape until extinguished.The burning rate curve is similar under different ignition points as to the fire spread of external insulation materials in high-rise building,forming two peaks.