环境压力对隧道竖井排烟影响的数值模拟研究  

Numerical simulation on the influence of ambient pressure on smoke exhaust in tunnel shafts

作　　者：赵江平[1] 鲍旺旺 Zhao Jiangping;Bao Wangwang(School of Resources Engineering,Xi'an University of Architecture and Technology,Shaanxi Xi'an 710055,China)

机构地区：[1]西安建筑科技大学资源工程学院,陕西西安710055

出　　处：《消防科学与技术》2024年第6期813-819,共7页Fire Science and Technology

摘　　要：通过FDS数值模拟,研究环境压力对隧道火灾的烟气蔓延规律、烟气分层特性和竖井排烟效果的影响。研究表明:低压环境下隧道顶棚的烟气具有更高的温度,火源-竖井和竖井下游区域顶棚温度的纵向衰减曲线均符合指数分布,温度衰减系数随着环境压力的增加而减小;火源-竖井区域的烟气运动由热浮力主导,层化曲线变化趋势不明显,竖井下游区域层化曲线受环境压力的影响较大,随着环境压力的降低,层化曲线出现顺时针旋转的趋势,层化强度降低,烟气层稳定性下降;低压环境中竖井的排烟效果要优于常压状态下的竖井,且竖井底部产生吸穿现象的临界高度也有所增加。因此,与一般海拔地区相比,海拔较高地区的隧道发生火灾时,较高竖井的排烟效果更好,吸穿临界高度更高,对下游烟气层稳定性的影响更小,更利于疏散排烟。Through FDS numerical simulation,the influence of ambient pressure on the smoke spread law,smoke stratification characteristics,and vertical shaft smoke exhaust effect of tunnel fires was studied.Research has shown that the smoke on the tunnel ceiling in lowpressure environments has a higher temperature,and the longitudinal attenuation curves of the ceiling temperature of the fire sourcevertical shaft and downstream area of the vertical shaft follow an exponential distribution.The temperature attenuation coefficient decreases with the increase of ambient pressure;The smoke movement in the fire source vertical shaft area is dominated by thermal buoyancy,and the trend of layering curve change is not obvious.The layering curve in the downstream area of the vertical shaft is greatly affected by ambient pressure.As the ambient pressure decreases,the layering curve shows a clockwise rotation trend,the layering intensity decreases,and the stability of the smoke layer decreases;The smoke exhaust effect of a vertical shaft in a lowpressure environment is better than that of a vertical shaft under normal pressure,and the critical height for the occurrence of suction penetration at the bottom of the vertical shaft has also increased.Therefore,compared with general altitude areas,when a tunnel fire occurs in higher altitude areas,the smoke exhaust effect of the higher vertical shaft is better,the critical height of suction is higher,and the impact on the stability of the downstream smoke layer is smaller,which is more conducive to evacuation and smoke exhaust.

关 键 词：隧道火灾 竖井排烟 环境压力 烟气分层 数值模拟 

分 类 号：X913.4[环境科学与工程—安全科学] TU998.1[建筑科学—市政工程]