隧道内列车着火的火焰顶棚射流温度特性研究

Temperature Characteirsitics of Flame Ceiling Jet Generated by Fire on Train in Subway Tunnel

通过隧道列车火灾的1∶8缩尺模型实验和数值模拟,研究了列车头部、尾部等不同位置着火时火焰顶棚射流的温度特性,并与列车中部着火的情况进行了对比。结果表明:列车头部、尾部着火时,火焰顶棚射流的最高温度出现在距隧道顶δ=0.25H的位置(H为火源至顶棚的高度),中部着火时出现在δ=0.18H的位置,均不同于纯烟气顶棚射流的最高温度出现在0.01H以内的情况;火焰顶棚射流燃烧稳定后,温度沿隧道纵向变化的规律是分段的——列车头部、尾部着火时,各断面的最高温度以抛物线规律衰减,列车中部着火时各断面的最高温度则以线性规律衰减;离列车一定距离后,夹带火焰明显减少,火焰顶棚射流的最高温度都呈指数形式衰减。

In this paper, 1：8 scale model experiments and numerical simulations were performed to analyze the temperature characteristics of flame ceiling jet generated by a fire at the head and the tail of a train in a subway tunnel. The results were then compared with those at the train center. It is found out that, if the fire occurs at the train head and tail, the maximum temperature of the flame ceiling jet appears at the location of δ= 0. 25H away from the tunnel roof, while it appears at the location of δ= 0. 18H if the fire occurs at the train center, all these being different from that of the gas ceiling jet appearing at the location of 0. 01H away from the tunnel roof; that the vertical temperature along the tunnel changes piecewise under a stable combustion state, so the maximum temperature at the fire on the train head and tail reduces parabolically, while that at the fire on the train center reduces linearly; and that, being a certain distance away from the train, the flame significantly weakens, and the maximum temperature of the flame ceiling jet exhibits an exponential decay.