大长径比管道汽油-空气混合气爆炸与抑制实验研究*

为探究狭长受限空间中油气爆炸失控时的发展状态，探索高效环保的油气爆炸抑制方法，利用长径比155的管道开展92号汽油-空气混合气爆炸发展规律和七氟丙烷主动抑爆技术研究。通过测量不同端部开口条件下油气爆炸超压、火焰传播速度、火焰强度等参数，对比研究空爆和抑爆工况下的油气爆炸变化规律，探讨长直管道中的油气爆炸特性，分析七氟丙烷抑爆效果。结果表明:大长径比管道中，端部开口泄爆对降低油气爆炸破坏能力的作用较小，开口与否对最大超压峰值的出现位置有影响；长直管道空爆时，油气爆炸由爆燃发展成爆轰，管道尾部的爆轰波速可达近2 000 m/s；密闭管道中，爆轰发生前火焰传播呈“已燃区-火焰锋面-待燃区-前驱激波-未燃区”的2波3区结构；主动抑爆方式下七氟丙烷抑爆效果良好，最大超压峰值降低幅度可达90%，火焰传播被及时阻断。

Experimental study on explosion of gasoline-air mixture and its suppression in pipeline with large length-diameter ratio

In order to explore the development state when fuel-air explosion is out of control in long-narrow confined space and investigate efficient and environmental-friendly methods for suppressing the explosion,the development laws of NO.92 gasoline/air mixture explosion and its inhibition by heptafluoropropane(C3F7H)in an active way were studied in a horizontal pipe with the length-diameter ratio of 155.By measuring overpressure,flame propagation speed and flame intensity of the explosion with the pipe end open or not,some development rules between normal gasoline-air explosion and explosion suppressed by C3F7H were compared and concluded,then the explosion characteristics in a long straight pipeline were discussed in detail,and the explosion suppression effect of C3F7H was analyzed objectively.The results showed that for pipelines with large length-diameter ratio,the venting by opening end had little effect on reducing the damage ability of gasoline-air explosion,but influenced the appearance location of the maximum peak overpressure.In the case of normal explosion in a long straight pipe,the gasoline-air explosion developed from deflagration to detonation,and the detonation wave velocity could reach nearly 2000 m/s at the end of pipeline.In the closed pipe,the flame propagation before detonation presented the structure of two waves and three zones,namely“burned zone-flame front-zone to be burned-leading shock-unburned zone”.By means of active suppression,C3F7H showed high efficiency in controlling explosion,the maximum peak overpressure could be reduced by 90%,and the flame propagation was blocked in time.