高海拔隧道全尺寸火灾烟气及温度场特征试验研究

发布时间：2018-01-25 20:42

  本文关键词： 高海拔 隧道火灾 热释放率 烟雾蔓延 温度分布　出处：《土木工程学报》2017年08期 　论文类型：期刊论文

【摘要】：通过对海拔为4100m的高海拔隧道进行全尺寸火灾试验,揭示高海拔隧道火灾烟气下沉及温度场变化特征。试验采用三种不同尺寸火源(0.8m~2、1.0m~2、2.0m~2),对隧道火灾烟气蔓延特征、火区最高温度、隧道拱顶纵向温度分布进行研究。试验研究结果表明:隧道火灾试验初期及燃烧稳定阶段,火源附近隧道上层烟气与下层冷空气分界明显,火灾后期烟气下沉严重;较小风速有利于高海拔隧道小规模火灾烟气逆流层纵向和垂向蔓延的控制。隧道火灾温度场研究表明:隧道火灾温升速率随火源热释放率增大而增加;火源附近20m范围内温度衰减速率较快,远火源区域隧道拱顶纵向温度衰减较慢,趋于平缓;通过对火源上方拱顶烟气温度分析,发现隧道火灾探测采用差温报警模式较定温报警模式更加有效,并得出10℃/min的温升速率可基本满足高海拔隧道小规模火灾的初期报警;隧道拱顶纵向温度分布规律导致火源远场烟气下沉严重而近火源区域烟气层化较好的特征。高海拔隧道火灾温度分布特性试验研究,可为高海拔隧道火灾动力特性研究提供依据,为高海拔隧道人员疏散逃生提供指导及建议。
[Abstract]:Based on the full-scale fire test of the high-altitude tunnel at 4100m altitude, the characteristics of smoke sinking and temperature field variation of the tunnel fire are revealed. Three different sizes of fire source (0.8mm2) are used in the test. The characteristics of smoke spread in tunnel fire and the highest temperature in the fire zone are obtained. The longitudinal temperature distribution of the tunnel arch roof is studied. The experimental results show that the boundary between the upper flue gas and the lower cold air in the tunnel near the fire source is obvious at the initial stage of the tunnel fire test and the stable stage of combustion. The smoke sink seriously in the late period of fire; Small wind speed is beneficial to control the vertical and longitudinal spread of flue gas countercurrent layer in small scale fire in high altitude tunnel. The temperature field of tunnel fire shows that the temperature rise rate of tunnel fire increases with the increase of heat release rate of fire source. The temperature decay rate is faster in the range of 20m near the fire source, and the longitudinal temperature attenuation of the tunnel vault in the far fire source area is slower and tends to be gentle. Through the analysis of flue gas temperature above the fire source, it is found that the differential temperature alarm mode is more effective than the fixed temperature alarm mode in tunnel fire detection. It is concluded that the temperature rise rate of 10 鈩，

本文编号：1463652