地铁隧道火灾中回燃现象的试验研究  

Experimental Study on the Backdraft Phenomenon in Subway Tunnel Fire

作　　者：毛军[1] 郗艳红[1] 白光[2] 樊洪明[3] 

机构地区：[1]北京交通大学,北京100044 [2]北京市劳动保护科学研究所,北京100054 [3]北京工业大学,北京100044

出　　处：《铁道学报》2010年第6期132-139,共8页Journal of the China Railway Society

基　　金：国家自然科学基金资助项目(51078031);科技部重大基础研究前期研究专项项目(2005CA04700);北京市自然科学基金资助项目(8101004)

摘　　要：国内外对地面建筑火灾的腔体回燃,进行了较多研究,但对地铁隧道这类大长细比空间中的火灾回燃研究得很少。为此,采用1∶8缩尺比例的地铁隧道火灾模型试验装置进行回燃试验,分析隧道回燃与腔体回燃的不同。结果表明,产生回燃的决定性参数是燃料挥发份的质量百分比,且存在临界值;通风条件不同,回燃产生时的燃料挥发份的质量百分比不同,单隧道自然通风和双隧道机械通风条件下的临界值分别为8.78%和11.71%;单隧道自然通风条件下的回燃和腔体回燃相似,点火延迟是重力流延迟;双隧道机械通风条件下的回燃与腔体回燃则不同,点火延迟是点火源延迟;回燃受到送入隧道内新风湿度的影响,增大新风湿度可以抑制回燃的产生,且新风风速与其湿度之间存在优化匹配关系;对送入隧道的新风加湿是对地铁隧道火灾及回燃进行抑制的经济可行的方法,对地铁消防具有重要的借鉴意义。Researches on the occurrence of backdraft in compartment fires have obtained some results in surface buildings.But the backdraft taking place in subway tunnels,i.e.,in underground spaces with large slenderness ratios has not been paid enough attention to.Experiments have been conducted to investigate the difference between the two kinds of backdrafts by the 1/8 reduced-scale subway tunnel fire model.The results indicate as follows：the key parameter determining the occurrence of backdraft in subway tunnel fire is the mass concentration of the volatile component of the fuel and it has a critical value;the mass concentration of the volatile component changes with different ventilation conditions,its critical value is 8.78% in the single-tunnel under natural ventilation and 11.71%in the double-tunnel under mechanical ventilation;the backdraft in the single-tunnel under natural ventilation is similar to that in the compartment,and the ignition delay is the gravity flow delay;the backdraft in the double-tunnel under mechanical ventilation is different with that in the compartment,and the ignition delay is decided mainly by the ignition source delay;the backdraft is influenced by the humidity of the fresh wind flowing to the fire source,the humidity can be increased to inhibit the occurrence of backdraft and an optimized match exists between the humidity and the velocity of the fresh wind;it is economic and feasible to inhibit backdraft by humidifying the fresh wind flowing into the tunnel and the method has important reference to subway fire fighting.

关 键 词：地铁 隧道火灾 腔体火灾 回燃现象 质量百分比 临界条件 

分 类 号：U231.4[交通运输工程—道路与铁道工程] TU89[建筑科学]