Abstract A series of numerical simulations about tunnel fires are carried out to study the performance of different arrangements of natural ventilation shafts in a 500 m tunnel. Two to four identical shafts are arranged in a group at the centerline and the sideline of the tunnel ceiling. The characteristics of the temperature distribution, velocity field and the total amount of smoke exhausted from each shaft group are investigated for each arrangement. The results have shown that when the fire heat release rate is 20 MW, boundary layer separation occurs in all the shafts in the series of simulations. At the same fire heat release rate, when the number of shafts, n, is ≤ 2, the smoke exhaust performance of the shaft groups arranged on the centerline of the tunnel ceiling is better than that on the sideline of the tunnel ceiling while n is >2, the shaft groups arranged on the sideline have a better overall smoke exhaust performance. The Richardson number of 1.4 proposed by Ji et al. is still applicable to determine the flow phenomena between boundary layer separation and plug-holing.

中文翻译：

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隧道火灾中竖井组布置对自然通风性能影响的数值研究

摘要 为研究某500 m隧道自然通风井不同布置方式的性能，对隧道火灾进行了一系列数值模拟。2～4根相同的竖井在隧道顶板的中心线和边线处成组布置。研究了每种布置的温度分布、速度场和从每个轴组排出的烟气总量的特征。结果表明，当火灾放热率为20 MW时，系列模拟中所有竖井均出现边界层分离。在相同的火灾热释放率下，当竖井数n≤2时，布置在隧道顶板中心线上的竖井组排烟性能优于隧道顶板边线上的竖井组排烟性能，而n为>2, 布置在边线上的轴组具有更好的整体排烟性能。Ji 等人提出的理查森数 1.4。仍然适用于确定边界层分离和塞孔之间的流动现象。