隧道与横通道交叉角对火灾烟气蔓延影响机制研究

Research on influence mechanism of crossing angle between tunnel and cross passage on fire smoke spread

为探索隧道与横通道交叉角对火灾烟气蔓延的影响机制,采用FDS数值模拟,研究横通道与隧道不同交叉角情况下火灾烟气温度、浓度、烟气层高度等的变化规律,建立开启火源下风向横通道时隧道内烟气最高温度修正公式,提出烟气纵向蔓延恢复长度的概念,并探讨其影响规律。结果表明:隧道和横通道交叉角越小,隧道内同一位置烟气层高度越高,当交叉角由90°降低到30°时,烟气层高度最大增加32%;烟气纵向蔓延恢复长度与交叉角及通风速率呈正相关,而与火源功率几乎无关。研究结果对隧道通风排烟系统设计及相关标准的制定具有参考意义。

In order to explore the influence mechanism of crossing angle between tunnel and cross passage on the fire smoke spread,the variation law of fire smoke temperature,concentration and flue gas layer height under different cross angles of cross passage and tunnel are studied by FDS numerical simulation.A modified formula for the maximum temperature of smoke in the tunnel when opening the cross passage downstream the fire source was established,then the concept of the recovery length of longitudinal smoke spread was put forward,and the influence laws were studied.The results showed that the smaller the cross angle between tunnel and cross passage,the higher the height of smoke layer at the same location in the tunnel,and when the cross angle decreased from 90°to 30°,the height of smoke layer increased by 32%at maximum.The recovery length of longitudinal smoke spread was positively correlated with the crossing angle and the ventilation speed,while almost independent of the power of fire source.The research results have reference value for the design of tunnel ventilation and smoke exhaust system and the formulation of related standards.