液化石油气点火能试验及爆炸火焰传播分析

Experiment on Ignition Energy of LPG and Analysis on Flame Propagation of Explosion

为研究液化石油气体积分数与点火能的关系以及爆炸火焰的传播过程,在实验室应用特制的爆炸试验装置,采用调节点火能和液化石油气体积分数的方法,进行一系列爆炸试验,并使用高速摄像机记录爆炸的动态过程。试验结果表明,当液化石油气的试验爆炸体积分数在5%～9%时,其体积分数与点火能之间呈现比较平缓的变化关系,而当其体积分数小于5%或大于9%时,体积分数的稍微变化,其点火能将发生显著的变化。爆炸过程图像分析显示,在爆炸初期,火焰阵面的微分加速起主导作用。随着火焰从点火源位置向四周扩散,光滑的层流火焰开始逐步"湍流化",火焰阵面出现皱折,燃烧面积增加,火焰传播速度逐渐上升直至最大值。在整个过程中,火焰阵面出现非稳定的加速。

The relation between volume fraction of LPG and ignition energy and analysis on fame propagation of explosion were studied. A series of explosion experiments were conducted based on a special device by adjusting volume fraction of LPG to ignition energy. The high-speed camera was used to record the dynamic process of LPG explosion. The results show that the relation between volume fraction and ignition energy changes slowly when the volume fraction of LPG explosion is amongst 5% -9%, and any slight changes of volume fraction lead to significant changes of ignition energy when the volume fraction is less than 5% or greater than 9%. Image analysis on the explosion shows that flame acceleration in the differential form plays a leading role in the initial explosion. With spreading of flame from ignition position to sur- rounding, smooth laminar flame becomes turbulent flame. The flame front appears some wrinkles, and it also increases the burning area. At the same time, the spreading speed of flame increases graduall reaches the maximum. In the whole process of the spreading of flame, the flame front accelerates stable form. y until it in an instable form.