甲烷-煤尘爆炸物火焰传播特性

Flame Propagation and Combustion in Methane-Coal-Air Mixture

在10m3的爆炸罐中对体积分数为8%的甲烷和75g/m3煤尘的混合物进行了系统的燃烧爆炸实验。分别利用光测方法和压力方法得到了爆炸物的层流燃烧速度、火焰传播速度、火焰厚度、马克斯坦长度以及爆炸特征值的变化规律。结果表明,在常温常压下,当点火能为40J时:利用光测法得到的8%甲烷与75g/m3煤尘混合物的燃烧速度为0.437m/s,而根据压力-时间关系得到的混合物燃烧速度为0.459m/s,两者符合较好;用火焰厚度与马克斯坦长度判定的火焰发展趋势相同,即向外传播的火焰趋于稳定;爆炸物的爆炸特征值最大值出现在0.5m处,壁面的爆炸特征值偏小。

Combustion and explosion experiments are carried out in an explosion tank of 10 m3 for the mixture of 8% methane-75 g/m3 coal dust-air.Optical method and pressure method are adopted to obtain the laminar burning velocity,flame speed,flame thickness,Markstein length as well as the explosibility index of the mixture when the flame spread.The results show that the burning velocity of the mixture of methane-coal dust-air is 0.437 m/s,while the value is 0.459 m/s according to the relationship between pressure and time,and the results from the two methods are coincide.The flames trends determined by flame thickness and Markstein length are the same,and both tend towards stability.The maximum of explosibility index occurs at 0.5 m,and the explosibility index at the wall of explosion chamber is a bit small.