环境风作用下聚氨酯泡沫水平火蔓延行为实验研究

为探究环境风速对聚氨酯泡沫水平顺流火蔓延的影响，开展多组工况对比实验，分析不同侧向风速对火蔓延典型特征参数（火焰形态、质量损失和近域场温度及辐射）影响。实验结果表明：侧向风速会缩短热解前锋预热角形成时间，且预热角度大小与风速呈负相关，预热角减小会增大火焰前锋对预热区热反馈面积，使火蔓延速度增加；火焰前锋受侧向风速拉伸效应主导下的空气卷吸作用，火蔓延过程中熔融滴落频率增大，加大次生火灾危险性；同时火蔓延过程中材料的质量损失率随风速增加而增加；风速的冷却效应在火蔓延前期占主导地位，但仍会促进火蔓延速度，且水平板材上下两侧辐射峰值差逐渐增大。

Experimental study on horizontal fire spreadingof polyurethane foam under ambient wind

In order to explore the influence of ambient wind speed on horizontal downstream fire spread of polyurethane foam, several groups of comparative experiments were carried out to analyze the influence of different lateral wind speeds on typical characteristic parameters of fire spread (flame shape, mass loss, near-field temperature and radiation). The experimental results showed that lateral wind speed can shorten the formation time of preheating angle of pyrolysis front, and the preheating angle is negatively correlated with wind speed. The reduction of preheating angle will increase the heat feedback area of flame front to preheating area and increase the fire spread speed. The flame front is affected by air entrainment under the direction of lateral wind speed stretching effect, and the melting dripping frequency increases during the fire spreading process, which increases the risk of secondary fire. At the same time, the mass loss rate of materials increases with the increase of wind speed in the process of fire spread. The cooling effect of wind speed is dominant in the early stage of fire spread, but it will still promote the fire spread speed, and the radiation peak difference between the up and low sides of the horizontal plate gradually increases.