This paper investigates the effects of passenger blockage on smoke flow properties in longitudinally ventilated tunnel fires. A series of numerical simulations were conducted in a 1/5 small‐scale tunnel with the different heat release rates (50‐100 kW), longitudinal ventilation velocities (0.5‐1 m/s), passenger blockage lengths (2‐6 m), and ratios (0.17‐0.267). The typical smoke flow properties in different tunnel fire scenarios are analyzed, and the results show that under the same heat release rate and longitudinal ventilation velocity, the smoke back‐layering length, maximum smoke temperature, and downstream smoke layer height decrease with increasing passenger blockage length or ratio. The Li correlations can well predict the smoke back‐layering length and maximum smoke temperature in tunnel fire scenarios without the passenger blockage. When the passenger blockage exists, the modified local ventilation velocity that takes the blockage length and ratio into account has been proposed to correct the Li correlations. The smoke back‐layering length and maximum smoke temperature with the different blockage lengths and ratios can be predicted by the modified correlations, which are shown to well reproduce the simulation results.

中文翻译：

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乘客阻塞对纵向通风隧道火灾中烟气流动特性的影响

本文研究了纵向通风隧道火灾中乘客阻塞对烟气流动特性的影响。在一个1/5小型隧道中进行了一系列数值模拟，这些隧道具有不同的放热率（50-100 kW），纵向通风速度（0.5-1 m / s），乘客阻塞长度（2-6 m） ，以及比率（0.17-0.267）。分析了不同隧道火灾场景下典型的烟气流动特性，结果表明，在相同的放热率和纵向通风速度下，随着乘客阻塞的增加，烟气的背层长度，最高烟气温度和下游烟气层高度减小长度或比率。Li相关性可以很好地预测隧道火灾情况下的烟气背层长度和最高烟气温度，而不会造成乘客阻塞。当存在乘客阻塞时，已提出考虑阻塞长度和比率的修改后的局部通风速度，以校正Li相关性。可以通过修改的相关性来预测具有不同阻塞长度和比率的烟层的背层长度和最高烟气温度，这些相关性可以很好地再现模拟结果。