摘要
为解决坡度隧道临界风速存在的争议,以城市交通隧道的典型坡度构成为研究对象,通过数值模拟和搭建1∶8的坡度隧道模型实验台,对火灾工况中车辆沿坡度下行时的临界风速进行了研究,并与现有的较有影响力的2个临界风速模型"Kennedy模型和Wu&Bakar模型的计算值进行了对比.研究结果表明:车辆沿坡度下行时,控制烟气回流所需的临界风速大于相同火灾场景中平直隧道的临界风速,且随着隧道坡度的增加,车辆沿坡度下行时的临界风速逐渐增大.综合数值模拟和模型实验的研究成果,对现有多数规范中推荐使用的Kennedy临界风速模型中的坡度修正系数进行了修正,得到了新的坡度修正系数.当隧道坡度在5%以上时,建议使用Wu&Bakar临界风速模型进行烟气控制系统设计.
Tunnel with large slop is one of the main structures of the urban traffic tunnels. The effect of the slope on the critical velocity is the key factor for the smoke control system design in the kinds of tunnels. Centered on the controversy about the critical velocity in titled tunnel,numerical simulations and experimental studies by a 1 ： 8 small-scale tunnel mode on the critical velocity in these tunnels were studied,and comparison between the numerical and experimental results with those predicted by two famous models due to Kennedy and Wu ＆ Bakar was presented. The research results show that the critical velocity for the downward driving in a titled tunnel is larger than that in the normal level tunnel, and it increases with the tunnel’s slope increasing. New grade factor for the Kennedy model is derived based on the research results. Wu ＆ Bakar model is recommended to be used to calculate the critical velocity when the slope of tunnel is larger than 5 % .
出处
《北京工业大学学报》
CAS
CSCD
北大核心
2017年第11期1706-1712,共7页
Journal of Beijing University of Technology
基金
国家自然科学基金资助项目(51278018
51378040)
北京市自然科学基金资助项目(8132011)
关键词
坡度
临界风速
隧道火灾
数值模拟
实验研究
slope
critical velocity
tunnel fire
numerical simulation
experimental study
