隧道防火门分流对端部临界送风风速的影响

Influence of tunnel fire doors on the critical supply air velocity at the end of the diversion

在单洞双线轨道交通隧道发生火灾时,人员从火源上游防火门疏散,防火门的分流作用将影响端部送风风速。采用理论计算与数值模拟相结合的方法探究其影响关系,首先通过理论分析推导出了端部临界送风风速公式;随后,利用PyroSim软件建立了全尺寸模型,并针对不同数量防火门、火源热释放速率、隧道高度的分流情况进行了研究。结果表明:在相同火源热释放速率下,防火门的分流流速随着防火门开启数量的增多而减少;相同位置防火门的分流流速随火源热释放速率的增大呈指数增长的关系;防火门总分流量随防火门开启数量与热释放速率的0.3次方之积呈线性增长的关系,而受隧道高度的影响较小;结合理论推导,建立了端部临界送风风速的数学模型。研究结果为隧道火灾情况下的人员疏散和通风设计提供了科学依据。

When a fire breaks out in a single-hole double-track rail transit tunnel,the personnel are evacuated from the fire upstream through the fire door,and the diversion effect of the fire door will affect the air velocity at the end.The influence relationship is explored by combining theory and numerical simulation.The formula of the end critical blast velocity is derived by theoretical analysis.Using PyroSim software,a full-scale model was established to study the diverting conditions of different number of fire doors,heat release rate and tunnel height.The results show that under the same heat release rate,the diversion velocity of fire doors decreases with the increase of the number of fire doors opened.The diversion velocity of the fire door at the same position increases exponentially with the increase of heat release rate.The total flow rate increases linearly with the product of the number of fire doors opened and the 0.3 power of the heat release rate,and is less affected by the tunnel height.Finally,a mathematical model of the end critical air supply velocity was established,which provides a scientific basis for the evacuation and ventilation of the tunnel in case of fire.