摘要
鉴于CFD在火灾模拟方面能够准确反映出火灾过程中烟气、温度、CO浓度等的分布特性,采用CFD对不同海拔条件下的隧道火灾进行模拟计算。计算结果表明,火源功率相同时,随着海拔的升高,上层烟气纵向蔓延速度以及下层新鲜空气向火源补充速度均增大。CO浓度以隧道中线为轴两侧对称分布,隧道中线上浓度最低;1.5m高度处,CO首先出现在隧道出口位置,随后向回蔓延;同一断面上层CO浓度大于下层CO浓度,海拔的升高导致CO生成量增多,高浓度区域范围变大。另外,随着海拔的升高,火源附近拱顶烟气温度增大;不同海拔条件下,拱顶烟气温度沿途均呈幂指数衰减,海拔越高,温降的速率越快。
CFD simulation can accurately reflect the distribution of smoke,temperature and CO concentration in tunnel fire,so it is used to compute tunnel fire in different altitude.The results show that the up-layersmoke diffusion velocity becomes bigger and the supplying velocity of down-layer fresh air for fire grows with the rise of altitude.CO concentration distributes symmetrically on both sides of the midline of tunnel and it is lowest in the midline.CO firstly appears at the exit of the tunnel and then back-flows at the height of 1.5m.CO concentration is much higher at upper layer than that at lower layer,CO will be produced more at high altitude and the high concentration area will be larger.The ceiling temperature near the fire increases with the increase of altitude.Ceiling temperature decays along the tunnel in an exponential function no matter in high altitude or in low altitude,and it decays faster in high altitude.
出处
《工业安全与环保》
北大核心
2016年第8期11-13,20,共4页
Industrial Safety and Environmental Protection
基金
国家自然科学基金(51404178)
