某单洞双向隧道列车火灾的烟气蔓延特性及防控研究

Smoke Movement and Control of Island High-speed Railway Underground Station Platform Fire

铁路隧道属于狭长形相对密闭空间,道路的长宽比十分大,与外部直接连接的仅有进口与出口,当发生火灾时后,烟气无法及时排出隧道,造成烟气在隧道内蔓延,不仅对隧道内人员生命安全产生威胁,还阻碍了消防人员及时进入隧道内进行扑救。其中,高铁地下单洞双向隧道不仅断面积大、行车组织复杂,而且发生火灾的位置往往不在纵向中心线上,因而隧道通风和排烟一直是工程设计中的重难点。以济滨隧道为研究对象,围绕单洞双向隧道的通风排烟模式和排烟参数,开展三维数值研究。其中,主要分析火灾发展过程中的烟气温度、碳烟密度、能见度等特征参数的分布情况。研究结果表明:在正常通风情况下,列车减速停车过程产生的活塞风效应,会起到一定的纵向排烟作用,但并不能将隧道内的烟气条件控制在对人体无害的范围;若采用大小为临界风速(3.7m/s)的纵向排烟模式,隧道内的温度可以得到有效控制,但下游人员逃生线路上的碳烟密度无法得到有效控制。提出的排烟模式和排烟参数可以为轨道交通领域类似工程通风排烟设计提供参考。

As the tunnel is a long narrow and relatively closed space,the road has a very large aspect ratio,and only the entrance and the exit are directly connected to the outside.When a fire occurs,the smoke cannot be discharged from the tunnel in time,causing the smoke to spread in the tunnel.It threatens the safety of the people in the tunnel,and it also prevents fire fighters from entering the tunnel for rescue.Single-hole double-track tunnel in railway transit system has the characteristics of complicated traffic organization with big cross-section area.For the design,ventilation and smoke exhaust is very important and difficult.This paper takes the single-hole double-track tunnel as the research object,and uses numerical simulation to study the smoke exhaust mode and exhaust parameters of the fire in the narrow space of the platform.It mainly analyzes the distribution of characteristic parameters such as smoke temperature,soot density,and visibility during the development of a fire.Research conclusions:In normal ventilation,the piston wind will assist the exhaust.In the longitudinal smoke exhaust mode,the size is critical wind speed(3.5m/s),the temperature in the tunnel can be effectively controlled.But the density of soot on the downstream escape route could not be effectively controlled.The proposed smoke exhaust mode and parameters are applicable to the fire smoke prevention and exhaust design of this type of tunnel.