地铁区间运行列车火灾早期烟气特性研究

Study on the Smoke Characteristics of Early Fire on a Running Train in the Tunnel

研究目的:探明区间运行列车火灾早期烟气特性是火灾快速精准探测、定位、预警的基础。本文通过建立运行列车火灾数值仿真计算模型,计算120 km/h区间运行列车车顶、车底、车头、车中、车尾6个工况火灾早期不同时刻空气温度、烟气浓度的变化规律。研究结论:(1)地铁区间运行列车火灾烟气呈非对称分布,烟气主要向车尾传播蔓延,火点前方1 m处已检测不到明显温度、烟气浓度变化;(2)测点温度和烟气浓度实时监测值与火源间距呈负相关规律,距火点相同距离处车底火灾空气温度较车顶火灾高100%,烟气浓度高500%;(3)相对速度差对绝对温度比影响较小,在5 m/s和10 m/s速度差下,距火点1 m处绝对温度比均大于0.45,在距火点3 m处绝对温度比均大于0.75;(4)本研究成果可为地铁防火标准完善和防排烟设计提供参考。

Research purposes:Figuring out the characteristics of early smoke flow from a running train fire is the foundation of fire detection,location and warning.Based on the numerical simulation model of train fire,six different location-fire models of roof,bottom,front,middle and rear of 120 km/h running train are used to study the variation of air temperature and smoke concentration at different times.Research conclusions:(1)The smoke is asymmetrically distributed,and tends to spread to the rear,it can not detect the changes in temperature and smoke concentration from 1 m distance ahead of the fire.(2)The real-time monitoring values of temperature and smoke concentration are negatively correlated with the distance from fire source,and the air temperature of an under-train-fire is 100%higher than that of a fire on the roof,and the smoke concentration is 500%higher.(3)The relative velocity has little influence on the absolute temperature ratio.The absolute temperature ratio is greater than 0.45(1 m away from the fire)and 0.75(3 m away from the fire)whether the relative velocity is 5 m/s or 10 m/s.(4)The research results could provide references for fire protection technical standards and the design of smoke management systems.