高速列车火灾烟气流动与控制的数值模拟

Numerical simulation of smoke flow and control in high speed train fire

为优化高速列车的防火设计,以简化的列车模型为研究对象,运用FDS大涡模拟法分析不同通风工况下的烟气扩散及控制。结果表明,固定火源功率0.5 MW,车厢全封闭情况下,烟气在60 s时即降到距车厢地板1.2 m以下;车厢连接处两侧车门打开时,20 s后烟气开始向相邻车厢扩散,烟气在车厢内沿顶棚向两侧蔓延,以火源为中心呈对称分布;车厢顶部自然排烟窗在烟雾传感器收到信号10 s后自动打开,温度整体下降,排烟窗排烟效率随火势扩大而下降,87 s时紧急逃生窗打开烟气浓度略有下降但不明显;两侧前室开启加压送风装置能使车厢温度降低10℃。机械排烟装置与送风装置联用方式排烟效果最优,改变送风角度能够进一步提高控烟排烟效率。该研究为高速列车防火性能与疏散逃生方案设计提供了理论依据。

This paper intends to optimize the fire protection design of high-speed train.The study involves using the simplified train model as the research object and applying the FDS large eddy simulation method to analyze the smoke diffusion under different ventilation conditions.The results show that in the presence of the fixed fire source power of 0.5 MW and the fully closed carriage,the smoke tends to drop to less than 1.2 m above the ground in 60 s;with the doors on both sides of the carriage joint being opened,the smoke will start to spread to the adjacent carriage after 20 s,and to both sides along the ceiling in the carriage,showing symmetrical distribution with the fire source as the center;the natural smoke exhaust window on the top of the carriage automatically opens after 10 s when the smoke sensor receives the signal,with the temperature dropping as a whole,and the smoke extraction efficiency of the smoke extraction window decreases with the expansion of the fire and when the emergency escape window is opened at 87 s,the smoke concentration shows a slight but an unobvious decrease;the operation of the pressurized air supply device in the front rooms on both sides allows the temperature of the carriage to be reduced by 10℃.The combination of mechanical smoke exhaust device and air supply device gives the best smoke exhaust effect,and changing the air supply angle enables a further improvement in the smoke control and exhaust efficiency.This study could provide a theoretical basis for the design of fire performance and evacuation scheme of high-speed train.