细长密闭管道内油气爆炸特性研究

针对长径比对密闭管道内汽油蒸汽和空气的混合气爆炸特性的影响进行实验。研究表明:细长密闭管道内的油气爆炸压力为两阶段上升,而压力上升速率曲线呈现出"双峰"结构;最大爆炸压力和取得最大pmax值的最佳油气浓度均随管道长径比L/D的增加逐渐减小;达到最大爆炸压力所需时间随管道长径比L/D的增加呈线性关系增加,且靠近最佳油气浓度的油气受管道长径比的影响较小,而偏离最佳油气浓度较远的油气受管道长径比的影响较大;随着油气浓度的增大,第二个压力上升速率峰值先呈指数增长,达到峰值之后呈负指数下降;当油气浓度低于临界浓度时,第二个压力上升速率峰值比第一个压力上升速率峰值低,而高于临界浓度时则反之;第一个和第二个压力上升速率峰值及取得最大(dp/dt)max2值的油气浓度均随管道长径比L/D的增加而降低。这些规律性的结论可为管道的防抑爆设计提供理论依据和重要参考。

Tests for explosion characteristics of gasoline-air mixture in an elongated closed tube

Tests for effects of aspect ratio L/D on explosion characteristics of gasoline-air mixture in a closed tube were performed.The results showed that explosion pressure of gasoline-air mixture in an elongated closed tube rises in the form of two stages,the pressure rise rate curve presents a double-peak configuration; the maximum explosion pressure and the optimal gasoline-air concentration to get the maximum p_max value decrease gradually with increase in L/D ratio; the time to reach the maximum explosion pressure increases linearly with increase in L/D ratio,and the gasoline-air mixture near the optimal gasoline-air concentration is less affected by the aspect ratio L/D in comparison with those far from the optimal gasoline-air concentration; the second peak of pressure rise rate increases exponentially firstly and decreases in a negative exponential form after reaching the peak with increase in gasoline-air concentration; when the gasoline-air concentration is lower than the critical concentration,the second peak of pressure rise rate is lower than the first peak,while the result is the opposite when the gasoline-air concertration is higher than the critical concentration.All the first and second peaks of pressure rise rate and the gasoline-air concentration to get the maximum (d_p/d_t)max2 value decline with increase in L/D ratio.These conclusions provided a theoretical basis and an important reference for the explosion proof design of pipelines.