Once a fire occurs in a long curve tunnel, the mixing of hot smoke flow and cold air leads to turbulence due to the curvature’s impact. This phenomenon results in a greater thermal pressure difference at the fire source and a substantially greater temperature field than in the straight tunnel. The longitudinal air flowing along the wall loses a lot of velocity in the curve tunnel due to the massive wall friction. Under the same fire extinguishing conditions, the curve tunnel and straight tunnel have different requirements for longitudinal ventilation. Factors such as tunnel curvature, longitudinal ventilation operation time, and ventilation velocity were all evaluated in order to investigate the influence of longitudinal ventilation parameters on the fire extinguishing effect of water mist in the curve tunnel. The fire extinguishing effect of water mist coupling with longitudinal ventilation in the curve tunnel is studied by numerical simulation, and the recommended values of ventilation operation time and ventilation velocity in the curve tunnel with the participation of the water mist system are given. The results show that (1) the fire extinguishing effect of water mist decreases with the increase of curvature under longitudinal ventilation and (2) fire prevention effect is best when water mist and longitudinal ventilation are used in the curved tunnel, and the ventilation velocity should be greater than 2 m/s.

中文翻译：

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曲线隧道火灾中不同纵向通风参数细水雾系统灭火效果的数值模拟

一旦在长曲线隧道中发生火灾，热烟流和冷空气的混合会由于曲率的影响而导致湍流。这种现象导致火源处的热压差和温度场明显大于直隧道。由于巨大的壁面摩擦，沿壁流动的纵向空气在曲线隧道中损失了很多速度。在相同的灭火条件下，曲线隧道和直隧道对纵向通风的要求是不同的。为研究纵向通风参数对曲线隧道细水雾灭火效果的影响，对隧道曲率、纵向通风运行时间、通风速度等因素进行了评价。通过数值模拟研究了细水雾耦合纵向通风在曲线隧道内的灭火效果，给出了细水雾系统参与的曲线隧道通风运行时间和通风速度推荐值。结果表明：(1)纵向通风下细水雾灭火效果随曲率增大而降低；(2)弯曲隧道采用细水雾纵向通风时防火效果最好，通风速度宜大于 2 m/s。给出了细水雾系统参与的曲线隧道通风运行时间和通风速度的推荐值。结果表明：(1)纵向通风下细水雾灭火效果随曲率增大而降低；(2)弯曲隧道采用细水雾纵向通风时防火效果最好，通风速度宜大于 2 m/s。给出了细水雾系统参与的曲线隧道通风运行时间和通风速度的推荐值。结果表明：(1)纵向通风下细水雾灭火效果随曲率增大而降低；(2)弯曲隧道采用细水雾纵向通风时防火效果最好，通风速度宜大于 2 m/s。