开口钢管内甲烷爆炸火焰厚度和压力发展特征

Flame thickness and pressure development characteristics of methane explosion in an open steel pipe

通过搭建长为20m、截面为0.08m×0.08m的非绝热开口钢管,研究了甲烷与空气预混气体发生爆炸后的火焰和压力发展特征。实验结果表明:火焰信号最强的时刻对应于火焰前锋反应区内某时刻,而火焰信号起始上升时刻与火焰前锋预热区起始时刻接近,应选择某点火焰信号起始上升时刻作为该点的火焰到达时间。随着远离点火源距离的增加,火焰厚度呈现先变薄后变厚的变化趋势,最大超压呈现先减小、后增大、再减小的趋势,火焰传播速度则呈先增大后减小的变化过程。非绝热开口钢管的实验条件对爆炸超压和火焰传播速度的影响较大。研究成果可为甲烷爆炸致灾机制及防控的研究提供参考。

Through establishing a non-adiabatic open pipe with a length of 20 m and a cross-sectional area of 0.08 m ×0.08 m, the flame and pressure development characteristics of premixed methane/air explosion were investi-gated experimentally.The results showed that the time of obtaining maximum flame signal value is corresponding to a certain time of flame-front reaction zone, while the time when the flame signal begins to rise is almost the same as that when the flame-front preheat zone starts.Thus, the time when the flame signal begins to rise at a certain point can be defined as the flame arrival time at this point.With increasing distance away from the ignition source, the flame thickness presents a changing trend of decreasing first and increasing after, and the maximum overpressure follows a trend of decreasing, increasing and decreasing, while the flame propagation speed shows a changing process of increasing and decreasing.The experimental conditions of non-adiabatic open steel pipe have an obvious effect on the explosion overpressure and flame propagation speed.The results can provide a reference for the further research on the disaster mechanism and control of methane explosion.