挑檐抑制 PMMA 竖直火蔓延数值模拟研究

摘要

In this paper ,the numerical simulation software FDS was used to establish the model of PMMA vertical fire spread . The influences of cornice length ,width and the ratio of width to length on vertical fire spread were studied by designing a series of conditions with various fire cornice lengths and widths .The results were as follows .When the cornice length reaches a critical value ,with the increase of the width ,the wall temperature above the cornice and heat release rate decreases .When the cornice width reaches a critical value ,with the increase of the length ,the wall temperature above the cornice and heat release rate decreases .With a higher cornice length ,the effective fire suppression width decreases gradually with the increasing of the length ,and finally remains fixed .Finally a dimensionless model for the critical point of fire cornice with heat release rate is established .%应用FDS数值模拟软件，建立PM M A竖直火蔓延模型，通过改变防火挑檐长度和宽度，设计一系列工况，对比分析挑檐长度、宽度以及宽长比对竖直火蔓延的影响。结果表明当挑檐长度为临界值时，随宽度的增加，挑檐上方壁面温度与热释放速率均逐渐降低；挑檐宽度为临界值时，随长度的增加，挑檐上方壁面温度与热释放速率逐渐降低；挑檐长度较长时，有效阻火的挑檐宽度随长度的增加而逐渐减小，最后固定不变，最终建立了防火挑檐的临界点与热释放速率的无量纲模型。