溢流火作用下外立面金属夹心保温板特殊引燃机制及火蔓延行为研究

Most fire projects on building insulation materials focus on the pyrolysis characteristics and the fire propagation behavior, do not pay attention to the effect of the panel style and installation. This project mainly focuses on the unique ignition mechanism and propagation process of the metal sandwich insulation panel under the spill fire from the window. The process can be summarized as melt extrusion, droplet fire, and vertical diffusion..The melt and extrusion behavior and stacking effect of thermoplastic materials of metal sandwich insulation panel under different heat release rate of spill fire were studied. The drops and the ignition mechanism of the metal thermoplastic panel with the restriction of the metal surface were revealed, and the time model of the ignition and extinguishing of droplets during melt dropping were established. The physical and installation parameters influence mechanism of this metal sandwich insulation panel of the droplet behavior was also studied, and the dropping rate, dropping mass and droplets temperature models with unilateral heating or bilateral heating were established, and the law of the vertical flame spreading of this insulation board was obtained. The critical parameters for the transformation from droplet fire to melt flow fire during the process of melt-drop of thermoplastic material were studied. The melt-extrusion morphology and ignition mechanism under the effect of droplet fire, which accumulated the temperature of the insulation panel surface, are obtained, and the acceleration mechanism of droplet fire (or melt flow fire) spreading to the downward panels was revealed. This study can improve the fire spread theory of exterior insulation materials, obtain the individual ignition mechanism and fire spreading law of metal sandwich insulation boards, and provide the theoretical basis and data support for building facade fire prevention.

目前，建筑外保温材料火灾研究主要集中在材料本体热解及其火蔓延行为，本项目则主要针对金属夹心保温板在溢流火作用下由“熔融挤出→熔滴火→垂向扩散”的特殊现象进行研究，揭示其引燃特性及火蔓延规律。.研究不同溢流火条件下金属夹心保温板内热塑性材料的熔融挤出行为及堆砌效应，揭示金属面板约束作用下热塑性材料熔滴及引燃机制，建立熔融滴落过程中的熔滴液点燃及熄灭时间模型。研究保温板物理参数、安装参数对热塑性材料熔滴行为的影响机制，建立单、双侧加热作用下熔滴液熔滴速率、质量及温度模型，获得保温板向上火蔓延规律。研究热塑性材料熔融滴落过程中熔滴火向熔流火转变的临界参数，获得下方保温板表面累积熔滴火作用下的熔融挤出形态及引燃机制，揭示熔滴火（熔流火）对向下火蔓延的加速机理。.本研究可完善外立面保温材料火蔓延理论，获得金属夹心保温板的特殊引燃机制及火蔓延规律，为建筑外立面火灾防治提供理论基础及数据支撑。

本项目则主要针对金属夹心保温板在溢流火作用下由“熔融挤出→熔滴火→垂向扩散”的特殊现象进行了研究，揭示其引燃特性及火蔓延规律。.研究了小尺寸PE金属夹芯保温板引燃行为及火蔓延燃烧现象，分析了不同样品长度、火焰长度以及火源功率工况下的引燃以及火蔓延特性，揭示了其火蔓延速率、质量损失速率、点燃时间、温度以及火焰高度等特性参数对引燃行为及火蔓延的影响机制。研制并搭建了缩尺寸实验平台，研究了夹芯板宽度、高度等物理参数对其燃烧蔓延的影响机制，提出了温度预测模型，获得了总热解速率及熔融滴落规律。研究了着火层上层开口对其燃烧特性的影响机制，揭示其开口对火焰卷吸行为的影响机制。研究了夹芯板与墙体间距及夹芯板包边对其火蔓延行为的影响机制，揭示了正反双面加热条件下的火蔓延特征，获得了夹芯板烟囱效应对其熔融滴落行为的影响规律。研究了夹芯板安装倾角对火蔓延行为影响，获得了不同倾角条件下的火蔓延特性，建立了基于传热变化的改进型火蔓延模型。研究了不同厚度夹芯板竖向火蔓延特性及熔融滴落池火燃烧特性，提出了夹芯板火蔓延速率拟合关系模型。研究了侧向风作用下的溢出火的脉动振幅及其对夹层板表面温度场分布的影响，提出了一种改进数学模型来预测火焰高度与开口尺寸之间的关系。研究了不同长宽比和跨度方式对夹芯板火灾后弯曲性能的影响，获得了长宽比对夹芯板火蔓延及火灾后弯曲性能的影响规律，提出了改进的Allen刚度预测模型和最大挠度模型。研究了不同火灾暴露时间和拼接缝隙对夹芯板火灾后冲击性能的影响，获得了拼接缝隙对夹芯板火蔓延及火灾后冲击性能的影响规律，提出了受到低速冲击后的变形量与温度的关系以及平均冲力与温度的数学模型，揭示了上、下表层中心点的凹陷值的线性关系。.本研究完善了外立面保温材料火蔓延理论，获得了金属夹心保温板的特殊引燃机制及火蔓延规律，为建筑外立面火灾防治提供了理论基础及数据支撑。