摘要
在全尺寸巷道火灾试验中,利用48路全自动数据采集系统,研究了快速密闭条件下火区的燃烧状况及温度和压力变化规律。试验发现,作用在风门上的抽吸力很大,很快降到很小;而燃烧区的温度迅速上升,烟及挥发分的产物迅速增加,氧的相对含量下降,之后燃烧减弱,温度迅速下降;燃烧区高温烟气沿着顶板逆向迁移至密闭墙,使附近的温度迅速上升至2 93℃;快速密闭设施必须要有一定的刚性和耐火特性;对贫氧燃烧,有利于火区的惰化,而对富氧高挥发分燃料火灾,有爆炸的危险;适当减少供风量。
This paper aims to report the authors' experimental research on the combustion state, the inversely smoke-flowing layers and its temperature and pressure changes in an enclosed burning zone after quick cutting off the air-flowing in the tunnel. As is known, it is of primary importance to prevent the tunnel fire from spreading. As a matter of fact, when the air-flowing was quick cut off at the inlet of a distance of 9 miles from the burning zone, there were powerful forces on the close-door, where the pressure would drop to 27.4 Pa and the potential pressure to 20.8 Pa, And after a ten seconds, it would turn to be very small. If the temperature in a burning zone were steeply rising up, smoke and volatile yields would increase too. At the same time, the amount of oxygen also drop. And, then, as the burning rate decreased, the temperature would drop down steeply; the inverse smoke-flowing layer moving to the close-door along the top floor from burning zone was driven by buoyant force, made the temperature near the close-door quick rising to 293 ℃ in 3 min. Therefore, it is highly recommended to close doors tightly. When the air-flowing is cut off it is favorable for resisting the fire spreading and more inert and combustible gases be released. But there may exist hazard of explosion for high volatile fuels pyrolysis under the conditions of rich oxygen. For the purpose, it is practical to control the fire by decreasing properly the air-flowing flux.
出处
《安全与环境学报》
CAS
CSCD
2005年第2期96-99,共4页
Journal of Safety and Environment
关键词
安全工程
巷道火灾
火区密闭
烟气逆流层
爆炸
safety engineering
tunnel fire
obturation of burning zone
inverse smoke-flowing layer
explosion
