甲烷/空气预混气的火焰传播过程

Observation of Propagating Flame of Methane-Air Mixture

为研究爆炸罐内甲烷/空气预混气中火焰的传播过程,利用高速摄像仪对火焰的传播过程进行了拍摄,用压力测试系统测量了爆炸罐中压力的成长过程,分析了火焰传播特性,计算了层流燃烧速度和不同位置的爆炸特性值.研究结果表明:根据高速摄像仪得到的图片将预混火焰分为火焰稳定成长及剧烈燃烧阶段,用两种方法测得预混气的层流燃烧速度分别为0.344和0.391m/s.爆炸特性值的最大值出现在离点火位置0.75m处,壁面的爆炸特性值偏小.

Combustion and explosion experiments were carried out in explosion tank of 10 ma volume with methane-air mixture （9.5% methane）. The methods of optical video camera and pressure measurement were adopted to observe the spread process of the flame. The characteristic parameters of the flame were obtained as the flame propagation, The results show that the observed flame could be divided into two stages, the flame stable growth stage and the strenuous burning stage. Depending on the adopted method, the burning velocity of the mixture methane/air is 0. 344 m/s and 0. 391 m/s, which indicates that the result from each of two methods is coincident basically. The maximum of explosive characteristic index occurs at 0. 75 m, while the explosive characteristic index at wall has a bit smaller value.