站厅两侧楼梯对火灾烟气流动影响的实验研究

当地铁站的站厅发生火灾时,连接地面与站厅的楼梯就成为了空气进入站厅和火灾烟气流向地面的唯一通道.在这些楼梯之间存在着对火灾烟气的竞争,竞争的结果是站厅一侧的楼梯成为烟气的出口,而另一侧的楼梯则成为空气的入口.为了了解这种烟气竞争现象的机理,首先分析了烟气在流动过程中受到的驱动力和阻力,然后研究了火源位置和楼梯截面尺寸对驱动力和阻力的影响,并在一1/8尺度的实验台上进行了实验验证.理论分析及实验研究结果表明,烟气竞争现象是浮力和空气流阻力共同作用的结果.该研究成果可为地铁站发生火灾时人员疏散应急预案提供科学依据.

Experimental study of the stairwells'influence on smoke propagation when fire occurs in a subway hall

When a subway hall catches fire,the stairwell is the passage not only for smoke flowing upwards to the ground,but also for air entering the subway hall.Thus,competition for smoke exists in stairwells,and the result of the competition is that some of stairwells become exits of smoke and the others become air inlets.To understand the mechanisms driving the motion of smoke,the driving force and resistance in various conditions were analyzed,and experiments were conducted in a 1/8 scale model to validate the analysis.The theoretical analysis and experimental results show that the competition for smoke is due to the combined effect of buoyancy and air resistance.This research can provide a scientific basis for emergent evacuation program during a subway fire.