高海拔隧道全尺寸火灾烟气及温度场特征试验研究  

Full-scale experimental study on smoke and temperature distribution characteristics of the tunnel fire at high altitude

作　　者：郭庆华[1] 闫治国[1,2] 朱合华[1,2] 

机构地区：[1]同济大学,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《土木工程学报》2017年第8期114-120,共7页China Civil Engineering Journal

基　　金：上海市科委科研项目(16DZ1200600);中央高校基本科研业务费专项资金(20153739)

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。Six full-scale tunnel fire experiments were conducted in a tunnel at a high altitude of 4100m. Three difference size of the fuel pool （0.8m^2 , 1.0m^2 and 2.0m^2 ） were used as fire sources. The smoke spreading characteristics, maximum temperature and longitudinal temperature distribution were studied. The results show that the interface between the upper hot smoke layer and the lower cold air is clear at early and steady stage of the fire but fuzzy at the decay stage, and the low ventilation velocity can control the longitudinal and vertical movement of the back-layering well in a small tunnel fire. Moreover, the temperature rise rate increases with the heat release rate. The longitudinal ceiling temperature decays fast in the vicinity of the fire source within 20m and slow away from the fire. Besides, based on the analysis results of the smoke temperature above the fire source, it is found that the fire detection adopting the differential temperature alarm is more efficient than that adoptingthe constant temperature alarm and the temperature growth rate of 10℃/min can work well in a small tunnel fire. In addition, by studying the longitudinal temperature distribution and the thickness of the smoke layer, it can be obtained that the smoke layer descend at first in the place far away from the fire source while has a well stratificationin vicinity of the fire. The characteristic of the temperature distribution of tunnel fires at high altitude can provide valuable data for the study on the fire dynamics of tunnel fire at high altitude and can offer guidance and suggestion for the human evacuation in case of a fire at high altitude.

关 键 词：高海拔 隧道火灾 热释放率 烟雾蔓延 温度分布 

分 类 号：U459.2[建筑科学—桥梁与隧道工程]