In more and more tunnels, natural ventilation mode with vertical shafts has been gradually employed. However, there are few studies investigating the influences of fire and shaft positions on natural ventilation performance currently. Therefore, this study investigated the effects of the transverse distance from fire source to tunnel sidewall, the longitudinal distance from fire source to shaft, and the transverse distance from shaft to sidewall on natural ventilation effectiveness in a tunnel fire by using Fire Dynamics Simulator. The typical characteristic parameters of smoke, such as mass flow rate, temperature distribution, and velocity vector were analyzed; besides, the phenomenon of plug‐holing was discussed. The results have shown that the mass flow rate of gas exhausted by the shaft decreases slightly with the increase of longitudinal distance from fire source to shaft. When the longitudinal distance from fire source to shaft is constant, changing the transverse distance from shaft to sidewall will have a more obvious effect on the effectiveness of exhausting smoke than changing the transverse distance from fire source to sidewall; in addition, the phenomenon of plug‐holing is more serious when the shaft is close to the sidewall.

中文翻译：

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城市隧道中自然通风竖井和火源位置影响的数值研究

在越来越多的隧道中，逐渐采用具有竖井的自然通风方式。但是，目前很少有研究调查火势和竖井位置对自然通风性能的影响。因此，本研究使用Fire Dynamics Simulator研究了火源到隧道侧壁的横向距离，火源到竖井的纵向距离以及竖井到侧壁的横向距离对隧道火灾中自然通风效率的影响。分析了烟的典型特征参数，如质量流量，温度分布和速度矢量；此外，还讨论了堵孔现象。结果表明，随着从火源到竖井的纵向距离的增加，竖井排出的气体的质量流量会略有下降。当从火源到竖井的纵向距离恒定时，改变从竖井到侧壁的横向距离比改变从火源到侧壁的横向距离对排烟效果的影响更为明显。此外，当轴靠近侧壁时，堵孔现象会更加严重。