狭长管道油气爆炸流场分布特征规律及分析

为研究狭长管道油气爆炸流场分布特征规律，搭建了狭长管道油气爆炸实验系统 ，并在狭长密闭管道中进行了油气爆炸实验。通过采集爆炸超压值和火焰强度值并进行 分析，得到以下结论:随着初始油气体积分数的增大，管道沿线最大爆炸超压值和升压 速率均呈现先增大后减小的趋势，在1.75%时达到最大，并且初始油气体积分数越接近 1.75%，升压速率增大越快；根据管道沿线最大超压分布规律可将初始油气体积分数分 为1.25%~1.55%、1.55%~2.20%、2.20%~2.65%3个部分；管道末端出现二次爆炸现象，爆 炸超压变化曲线可分为点火延迟、一次爆炸、二次爆炸、振荡衰减4个阶段；火焰持续 时间随油气体积分数的增加先下降后上升，油气体积分数为1.75%时火焰持续时间最短 。

Characteristic rules and analysis of flow field distribution for gasoline- air mixture explosion in narrow and long pipeline

In order to study the characteristic rules of flow field distribution for gasoline-air mixture explosion in narrow and long pipeline, an experimental system for gasoline-air mixture explosion in narrow and long pipeline was established, and the gasoline-air mixture explosion experiments were carried out in narrow, long and sealed pipeline. Through measuring and analyzing the values of explosion overpressure and flame intensity, it showed that with the increase in initial volume fraction of gasoline vapor, the maximum explosion overpressure and rate of pressure rise along the pipeline presented the trend of increase first and then decrease. The maximum values were achieved when the initial volume fraction of gasoline vapor was 1.75%, and when the initial volume fraction of gasoline vapor was more closed to 1.75%, the rate of pressure rise enlarged faster. According to the distribution rules of the maximum overpressure along the pipeline, the initial volume fraction of gasoline vapor could be divided into 3 phases: 1.25~1.55%, 1.55~2.20 %, 2.20~2.65%. The phenomenon of secondary explosion occurred at the end of pipeline, and the changing curve of explosion overpressure could be divided into 4 stages: ignition delay, first explosion, secondary explosion and oscillation attenuation. The duration time of flame decreased first and then increased with the increase in volume fraction of gasoline vapor, and it reached the shortest value when the volume fraction of gasoline vapor was 1.75%.