敞口端点火条件下甲烷-空气爆炸火焰传播实验

1.西安科技大学 安全科学与工程学院,陕西 西安 710054; 2.教育部 西部矿井开采及灾害防治重点实验室,陕西 西安 710054; 3.日喀则市安监局,西藏 日喀则 857000; 4.重庆三峡学院 土木工程学院,重庆 404100

甲烷爆炸; 点火位置; 火焰传播; 震荡; 锋面速度

Experiment on methane-air flame propagation characteristics by igniting at venting area
WANG Tao1,2,WEN Hu1,2,LUO Zhen-min1,2,REN Jun-ying1,3,DENG Jun1,2,GUO Zheng-chao4,CHENG Fang-ming1,2

(1.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploration and Hazard Prevention,Ministry of Education,Xi'an 710054,China; 3.Safety Supervision Bureau of Shigatse,Shigatse 857000,China; 4.School of Civil Engineering,Chongqing Three Gorges University,Chongqing 404100,China)

methane explosion; ignited area; flame propagation; fluctuant feature; flame velocity

DOI: 10.13800/j.cnki.xakjdxxb.2017.0503

备注

为研究敞口端点火条件下的甲烷-空气爆炸火焰传播特性,采用GB/T12474-2008气体爆炸极限测定系统,结合高速摄影仪,以甲烷-空气预混气体为实验介质,在相同点火能量和点火位置条件下,研究了7%,9.5%,11% CH4-Air爆炸火焰传播特性及变化规律。结果 表明:在半封闭实验管道敞口端点火条件下,CH4-Air爆炸火焰传播呈现出显著的震荡特点,火焰锋面在正向-反向-正向的循环中不断向管内蔓延。自敞口端向实验管道封闭端传播的过程中,锋前未燃混合气体依次经历了被火焰锋面压缩-反向拉伸-再压缩的过程,使得预混CH4-Air体系中CH4的体积分数被稀释、减小,导致后期火焰封面传播速度减小。已燃区域内水蒸气在爆炸高温环境和带电离子的作用下发生分解,产生的H2和O2改变了气体组分并使其进一步发生氧化反应,导致不规则光斑持续地出现-消失。

In order to research the flame propagation characteristics of methane-air mixture which ignited at venting area,methane was taken as experimental medium.A standard quartz tube test system and high-speed camera were employed to conduct the experiment.Flame characteristics of 7%,9.5% and 11% CH4-Air mixture with same test conditions were tested.Results showed that premixed methane-air flame presented significant fluctuant features being ignited at venting area.The flame front spread to tube end from the venting area in a circle of forward-backward-forward.During the flame spread process from venting area to the closed end of tube,the unburned gas mixture in flame front area was compressed first and then drawn reversely,resulting in the volume fraction of methane diluted,which decreased the velocity of flame propagation.The Vapor within the burned area decomposed to H2 and O2,changed the gas components and resulted in their further oxidation,leading to the irregular spots occurred and disappeared continuously.