可燃气体爆炸火焰和压力波传播特性的实验研究

EXPERIMENTAL STUDY ON PROPAGATING CHARACTERISTICS OF FLAME AND PRESSURE WAVES IN EXPLOSIONOF COMBUSTIBLE GASES

对预混可燃气体在圆形管道内的爆炸过程进行了实验研究 ,根据实验结果将超压的变化过程分为 4个阶段 ,将气体燃烧的变化过程分为 3个阶段。得出了计算火焰传播速度的经验公式。随着火焰的传播 ,火焰传播速度不断加快 ,且测点处的火焰传播速度越快、测点距点火处越远 ,燃烧时间就越短。对前驱冲击波与火焰面的相对时间及相对位置关系进行了分析。对爆燃转爆轰过程 (DDT)进行了初步研究 ,观察到此过程中前驱冲击波阵面仍然行进在火焰面的前方 ,但二者的间距在减小。火焰面紧跟在激波前缘的后面 ,二者同速传播 ,超压峰值的位置与火焰面重合。

Explosion process of premised combustible gases in tube is studied with experiments. According to the experimental results, the variation process of overpressure is divided into 4 stages, and the variation process of gas combustion is divided into 3 stages. The empirical formula of calculating flame-propagating speed is obtained. Flame propagating speed increases with time. The faster the flame propagating speed of the measured point is, and the longer the distance between the measured point and the firing point is, the shorter the combustion time is. Relative time and relative position of precursory shock waves and flame is analyzed. Elementary investigation about DDT process is carried on. It is found that precursory shock wave is still at front of flame and distance between shock waves and flame decreases gradually. In the end, flame and shock waves propagate with the same speed and the position of peak value of overpressure and flame front is coincident.