隧道火灾一氧化碳浓度及温升分布试验研究

为了掌握长大公路隧道内的火灾行为，提升特长公路隧道的火灾安全性，进行了水平通道中不同纵向通风强度下，一氧化碳浓度和温升空间分布关系的1∶6大尺寸火灾模型试验，并与Newman的研究结论进行了对比。试验在长66 m，宽1.5 m，高1.3 m的模型隧道中进行的。研究结果发现，Newman的研究结论并不适用于所有通风条件。一氧化碳浓度和温升的纵向分布和竖向分布都不尽相同。在纵向分布方向，烟流的温升随着远离火源的纵向距离的增加而显著衰减，然而一氧化碳浓度却并没有随着纵向距离的增加而发生改变。一定强度的纵向通风使得温升沿纵向的衰减率变得缓慢，然而，纵向通风对一氧化碳浓度的纵向分布特性影响甚微。在无纵向通风的情况下，相对于温升来讲，一氧化碳浓度随高度减小而衰减的速率明显比温升要慢。然而，随着纵向通风风速的增加，一氧化碳浓度和温升的竖向分布呈现出了很好的相似性。

Experimental Study on the Distribution of Carbon Monoxide Concentration and Temperature Rise in Tunnel Fires

To investigate fire behavior in tunnel and improve fire protection in long-sized road tunnel, a series of fire tests were conducted. Experiments were conducted in a quasi 1/6-scale model horizontal channel with internal dimensions of 66.0 m long×1.5 m wide×1.3 m high to investigate the spatial distributions of Carbon Monoxide(CO)volume concentration and those of temperature rise. The effects of longitudinal ventilation were also considered. And compared with the Newman conclusions. Results indicate that the Newman conclusions are not applicable to all conditions. Both in the longitudinal direction and in the vertical direction, profiles of CO volume concentration differ with those of temperature rise. In the downstream direction, the temperature rise of smoke flow decays rapidly with the increase in the distance from the fire origin, while CO volume concentration remains constant in the longitudinal direction. A larger longitudinal ventilation velocity leads to a slower decay in temperature rise along the longitudinal direction. However, longitudinal ventilation has a small influence on the longitudinal profiles of normalized CO volume concentration. Compared with the temperature rise, the CO volume concentration decays more slowly with the decrease in height under the conditions of no longitudinal ventilation. However, a relatively large longitudinal ventilation velocity leads to a high similarity between the vertical profile of CO volume concentration and that of temperature rise.