地铁站台疏散通道断面风场特性研究

针对规范中对地铁站台疏散通道断面（楼扶梯口处）仅给出风速限制的现状，采用计算机模拟和现场测试相结合的方法，对断面风场特性进行研究。站台公共区火灾排烟工况下，该断面风速呈现出沿高度方向的典型分层现象，自下而上分别为边界区、主流区、衰减区、回流区。人员活动大部分位于主流区，其内部风速为 3~6 m/s，有利于抑制烟气蔓延、补充新鲜空气。研究发现由于向下气流的渐扩效应在该断面顶部产生小面积回流，其对火灾烟气的潜在卷吸风险值得注意，并应在风速测试中判别气流方向。

Study on the flow characteristics of evacuationsection of subway platform

At present, there are just general restrictions of wind velocity on the evacuation section (stairs &elevator entrance) in the subway platform referring to the relevant technical codes of China. Therefore, the Computational Fluid Dynamics (CFD) simulation and field test were conducted to elaborate the flow characteristics of the section. On the ventilation mode of platform fire case,it was found typical stratification phenomenon along the height, namely, boundary zone, main stream zone, decay zone and reverse flow zone from the bottom to the top. The evacuated people will mainly be active in the main stream zone with the wind velocity as high as 3~6 m/s, which benefits for the smoke control and fresh air supply. The small area of reverse flow zone on the top is formed due to the divergent effect of the flow downwards, and the potential risk of smoke entrainment should be noticed. Furthermore, the flow direction should be judged in the wind velocity test of the evacuation section in the subway platform.