摘要
在顶部开口腔室内开展庚烷油池火的燃烧实验,研究了开口尺寸对火灾发展过程的影响.实验使用了2种直径的油池和6种大小的水平开口,并测量了燃料质量损失速率、腔室内的气体温度分布以及火源根部附近的气体浓度变化过程.结果表明,根据火焰熄灭的原因,燃烧可分为缺氧熄灭模式和燃料耗尽熄灭模式.在缺氧熄灭模式下,顶部开口尺寸对燃料消耗率、质量损失速率和气体温度分布的影响较小;火灾进入燃料耗尽熄灭模式后,质量损失速率以及气体温度均随开口尺寸增大而增大.同时,随着开口的增大,火焰熄灭时的氧气浓度变大.在顶部开口腔室火灾中,燃烧开始后,烟气在腔室内迅速沉降并充满整个腔室,"双区模型"不再适用.
Heptane pool fires were conducted in a compartment with a ceiling vent,and the effect of the ceiling vent size on fire development was investigated,in which two pool fires of different diameters and six vents of varying sizes were used.The fuel mass loss rate,gas temperature distributions at different locations and the gas concentration at the base of the fire were measured during the experiments.Results show that the oxygen-lack regime and fuel-exhaust regime are defined due to the cause of the flame extinction.In the oxygen-lack regime,the vent size has a small influence on the fuel consumption rate,fuel mass loss rate and gas temperature,while it has an increasing impact on them in the fuel-exhaust regime.Moreover,the oxygen concentration at extinction time increases with the increase in vent size.Smoke descends quickly to the floor and the compartment is filled almost completely with smoke,rendering so the ＂two-zone＂ model invalid for the fires in compartment with a ceiling vent.
基金
国家自然科学基金项目(50976109)
2008年度中国科学院研究生科技创新与社会实践资助专项资助
关键词
腔室火灾
顶部开口
质量损失速率
温度分布
气体浓度
compartment fire
ceiling vent
mass loss rate
temperature profile
gas concentration
