State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
J Hazard Mater. 2015;283:536-43. doi: 10.1016/j.jhazmat.2014.09.033. Epub 2014 Oct 13.
Many serious fires have occurred in recent years due to the ignition of external building insulation materials by hot metallic particles. This work studied the ignition of expandable polystyrene foam by hot metallic particles experimentally and numerically. In each experiment, a spherical steel particle was heated to a high temperature (within 1173-1373K) and then dropped to the surface of an expandable polystyrene foam block. The particles used in experiments ranged from 3mm to 7 mm in radius. The observed results for ignition were categorized into two types: "flaming ignition" and "no ignition", and the flaming ignition limit was determined by statistical analysis. According to the experimental observations, a numerical model was proposed, taking into account the reactant consumption and volatiles convection of expandable polystyrene decomposition in air. Three regimes, no ignition, unstable ignition and stable ignition, were identified, and two critical particle temperatures for separating the three regimes were determined. Comparison with the experimental data shows that the model can predict the range of critical ignition temperatures reasonably well.
近年来，由于外部建筑绝缘材料被灼热的金属颗粒点燃，发生了许多严重的火灾。本工作通过实验和数值研究了热金属颗粒对可膨胀聚苯乙烯泡沫的点燃。在每个实验中，一个球形钢颗粒被加热到高温（1173-1373K 之间），然后落到可膨胀聚苯乙烯泡沫块的表面。实验中使用的颗粒半径从 3 毫米到 7 毫米不等。观察到的点火结果分为两种类型：“火焰点火”和“无点火”，并通过统计分析确定了火焰点火极限。根据实验观察，提出了一个数值模型，考虑了在空气中可膨胀聚苯乙烯分解的反应物消耗和挥发物对流。确定了无点火、不稳定点火和稳定点火三种状态，并确定了两个用于区分这三种状态的临界颗粒温度。与实验数据的比较表明，该模型可以很好地预测临界点火温度范围。
