Zhang Yue, Yao Yongzheng, Ren Fei, Zhu Hongqing, Zhang Shaogang, Jiang Lei
School of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
Beijing Key Laboratory of Metro Fire and Passenger Transportation Safety, China Academy of Safety Science and Technology, Beijing, 100012, China.
Environ Sci Pollut Res Int. 2023 May;30(24):65074-65085. doi: 10.1007/s11356-023-26774-z. Epub 2023 Apr 19.
This paper systematically studied the coupling effect of ambient pressure and tunnel slope on temperature distribution and smoke propagation in full-scale tunnel fires under natural ventilation by FDS. The downstream length (longitudinal length from fire source center to tunnel downstream exit) was also considered. The concept of "height difference of stack effect" was put forward when analyzing the mutual effect of tunnel slope and downstream length on smoke movement. The results show that the maximum smoke temperature beneath the ceiling decreases with the increasing ambient pressure or tunnel slope. The longitudinal smoke temperature decays faster with the decreasing ambient pressure or slope in inclined tunnel. The induced inlet airflow velocity increases with the increasing height difference of stack effect, while decreases with the increasing ambient pressure. And the smoke backlayering length decreases with the increasing height difference of stack effect. Taking heat release rate (HRR), ambient pressure, tunnel slope and downstream length into account, the prediction models of dimensionless induced inlet airflow velocity and smoke backlayering length in inclined tunnel fires at high altitude were developed, which agree well with our and others' results. The outcomes of current study are great meaningful to fire detection and smoke control in inclined tunnel fires at high altitude.
本文利用FDS系统研究了自然通风条件下，环境压力和隧道坡度对全尺寸隧道火灾中温度分布和烟雾蔓延的耦合效应。同时考虑了下游长度（从火源中心到隧道下游出口的纵向长度）。在分析隧道坡度和下游长度对烟雾运动的相互作用时，提出了“烟囱效应高差”的概念。结果表明，天花板下方的最大烟雾温度随环境压力或隧道坡度的增加而降低。在倾斜隧道中，纵向烟雾温度随环境压力或坡度的降低而衰减得更快。诱导进气流速随烟囱效应高差的增加而增大，随环境压力的增加而减小。烟雾回流长度随烟囱效应高差的增加而减小。考虑热释放速率（HRR）、环境压力、隧道坡度和下游长度，建立了高海拔倾斜隧道火灾中无量纲诱导进气流速和烟雾回流长度的预测模型，该模型与我们和其他人的结果吻合良好。本研究结果对高海拔倾斜隧道火灾的火灾探测和烟雾控制具有重要意义。
