地铁长隧道排烟道代替部分中间风井方案烟气特性研究

Study on smoke characteristics of the scheme of smoke exhaust replacing part of air shaft in metro long tunnel

长区间隧道的防排烟系统设计通常是设置中间风井,但中间风井的设置容易受到多方面因素制约,可采用拱顶排烟道代替部分中间风井。为验证并拓展拱顶排烟道代替方案可行性,通过理论分析了3种排烟道设置方案对应的烟气控制方式。基于广州某区间地铁,通过数值模拟对排烟道设置方式进行验证,得到不同条件下3种排烟道设置方式控制烟气效果对比,结果表明:单侧送风1.6 m/s且排烟量为140 m^(3)/s时基本可以控制火灾位于中间通风区段时烟气的排出。当火灾位于靠近风井或排烟口下方时,送风风速1.4~1.6 m/s、排烟量140~150 m^(3)/s可有效控制烟气。证明了排烟道代替部分中间风井的可靠性,拓展了该方案的适用性。

In the design of smoke control and exhaust system of long interval tunnel,the middle air shaft is usually set,but the setting of the middle air shaft is easily restricted by many factors,so the smoke exhaust can be used instead of part of the middle air shaft.In order to verify and expand the feasibility of the alternative scheme of smoke exhaust,the smoke control methods corresponding to three smoke exhaust setting schemes were analyzed theoretically.Based on a certain subway in Guangzhou,numerical simulation was conducted to verify the smoke control effects of three kinds of smoke control methods under different conditions.The results show that,when the single-side air supply is 1.6 m/s and the smoke exhaust volume is 140 m^(3)/s,the fire can basically effectively control the smoke discharge in the middle ventilation section.When the fire is located near the air shaft or below the smoke outlet,the air speed of 1.4~1.6 m/s and the smoke exhaust volume of 140~150 m^(3)/s can effectively control the smoke,which proves that the smoke exhaust can replace part of the middle air shaft reliability,and expands the applicability of the scheme.