Effect of the blockage ratio on the smoke extraction efficiency in tunnel fires with natural ventilation

被引:16
|
作者
Wang, Jie [1 ,3 ,4 ,5 ]
Fan, Yongjie [1 ,3 ,4 ,5 ]
Wei, Yinqiu [1 ,3 ,4 ,5 ]
Jiang, Xuepeng [1 ,3 ,4 ,5 ]
Lu, Kaihua [2 ]
机构
[1] Wuhan Univ Sci & Technol, Sch Resource & Environm Engn, Wuhan 430081, Hubei, Peoples R China
[2] China Univ Geosci Wuhan, Fac Engn, Lumo Rd 388, Wuhan 430074, Hubei, Peoples R China
[3] Hubei Res Ctr Ind Safety Engn Technol, Wuhan 430081, Hubei, Peoples R China
[4] Hubei Key Lab Efficient Utilizat & Agglomerat Met, Wuhan 430081, Hubei, Peoples R China
[5] Wuhan Univ Sci & Technol, Fire Safety Technol Inst, Wuhan 430081, Hubei, Peoples R China
基金
中国国家自然科学基金;
关键词
Blockage ratio; Smoke extraction efficiency; Stack effect; Shaft; Tunnel fire; BOARD-COUPLED SHAFT; TEMPERATURE DISTRIBUTION; ROAD TUNNEL; VELOCITY; FLOW; LENGTH; TRAIN; JET;
D O I
10.1016/j.tust.2021.104165
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
Natural ventilation by shafts is widely applied in urban shallow tunnels due to its simple structure, steady smoke extraction efficiency and environment-friendly means. In order to investigate the influence of vehicle blockage on the smoke extraction efficiency of the shaft in tunnel fires, a series of n-heptane fire experiments were conducted in a 1:15 small-scale tunnel model with seven blockage ratios (0, 0.16, 0.24, 0.32, 0.40, 0.48, 0.56). The smoke extraction efficiency is calculated by the measured smoke temperature and CO volume fraction in the shaft and in the tunnel near the exhaust vent. Results show that the smoke extraction efficiency of the tunnel with shafts decreases firstly, then increases and drops lastly with the increasing blockage ratio. The smoke temperature in the shaft and at the downstream tunnel change similarly, which indicates that the vehicle blockage can affect the thermal energy discharged by a shaft. The main influence factors are the blocking effect, the necking effect caused by the blockage and the stack effect of the shaft, resulting in the variability of the smoke extraction efficiency. The smoke extraction efficiency reaches the maximum around the blockage 0.48 in the present tunnel, which can be referred to design the tunnel cross section in engineering applications.
引用
收藏
页数:8
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