基于空气幕与排烟系统的隧道火灾烟气控制研究*

为研究隧道火灾时空气幕与排烟系统复合模式下的烟气蔓延规律，优化选择防排烟方式，以某越江隧道为研究对象，运用FDS数值模拟方法探究射流速度、排烟量和空气幕与排烟口间距对防排烟效果的影响。结果表明:空气幕与排烟口间距对射流特性与烟气蔓延有较强影响，间距为30 m的控烟效果最佳；空气幕与机械排烟复合作用的控烟效果远优于每个独立系统，可实现可靠挡烟和有效排烟；当火源功率20 MW时，随空气幕射流速度的增加挡烟效果有所增加，但射流速度不宜过大，取20~30 m/s；机械排烟对温度与可见度影响比空气幕作用效果显著，一定程度上增加排烟量可降低所需气幕射流速度；综合考虑防排烟的有效性和经济性，取射流速度为20 m/s、排烟量为100 m3/s为最优防排烟组合方式。

Research on smoke control of tunnel fire based on air curtain and smoke exhaust system

In order to study the law of smoke spread under the combined mode of air curtain and smoke exhaust system during the tunnel fire,and optimize the selection of smoke protection and exhaust methods,taking a cross-river tunnel as the research object,the FDS numerical simulation method was used to explore the influence of jet velocity,smoke exhaust volume and distance between air curtain and smoke exhaust vent on the smoke protection and exhaust effect.The results showed that the distance between air curtain and smoke exhaust vent had stronger influence on the jet characteristics and smoke spread,and the smoke control effect with a distance of 30 m was the best.The smoke control effect of the combined mode of air curtain and mechanical smoke exhaust was much better than that of each independent system,and it could achieve the reliable smoke shielding and effective smoke exhaust.When the fire source power was 20 MW,the smoke shielding effect increased with the increasing jet velocity of air curtain,but the jet velocity should not be too high,selecting as 20~30 m/s.The mechanical smoke exhaust had more significant impact on the temperature and visibility than air curtain,and increasing smoke exhaust amount could reduce the required jet velocity of air curtain to a certain extent.Comprehensively considering the effectiveness and economy of smoke protection and exhaust,the optimal combination mode of smoke prevention and exhaust was taking the jet velocity of 20 m/s and the smoke exhaust amount of 100 m3/s.