煤尘挥发分及粒径对爆炸火焰长度的影响研究

为研究煤尘挥发分及粒径对爆炸火焰长度的影响及其变化规律，选取挥发分含量不同的四种典型烟煤煤样，分别制备成31.5、44、62.5、81.5、119、>150 μm六种粒径，利用煤尘爆炸性鉴定装置测试其爆炸火焰长度，并对其爆炸火焰长度变化规律进行分析。结果表明:随着挥发分含量的增加，不同粒径级别的煤尘爆炸火焰长度均呈增长趋势；在挥发分含量较低的区间，挥发分含量增加对爆炸火焰长度影响不大；在挥发分含量较高的区间，随着挥发分含量的增加其爆炸火焰长度也急剧增加，并且粒径越小增加的越快。对于同一实验煤样，随着粒径的增大，其爆炸火焰长度逐渐减小，粒径增大到150 μm以上时爆炸火焰几乎消失。爆炸火焰长度随粒径变化的变化率根据实验煤样的不同，呈现出两种变化规律，挥发分含量为18.99%和27.52%煤样的爆炸火焰变化率先增加再减小再增加，挥发分含量为32.20%和39.74%的煤样呈现先增加再减小的趋势，但四组实验煤样的爆炸火焰长度变化率都在44～62.5 μm的粒径变化量时达到最大值。

Study on influence to length of explosion flame by volatile content and particle size of coal dust

Abstract: To study the influence and its change laws of volatile content and particle size of coal dust on length of explosion flame, four typical coal samples with different volatile contents were selected and prepared as six particle diameters, including 31.5μ m, 44μ m, 62.5 μm, 81.5μm, 119 μm, and > 150 μm. The identification device of coal dust explosion was applied to test the length of explosion flame, and the change laws on length of explosion flame were analyzed. The results showed that the length of explosion flame for coal dust with different levels of particle diameter presents an increasing trend with the increase of volatile content. In the range of low volatile content, the increase of volatile content has little effect on the length of explosion flame, while in the range of higher volatile content, the length of explosion flame increases sharply with the increase of volatile content, and the smaller the particle size, the faster the increase. For the same coal sample, with the increase of particle diameter, the length of explosion flame decreases gradually and almost disappears when the particle diameter is larger than 150μm. The change rate of length of explosion flame with particle diameter presents two kinds of change laws for different coal samples, for the coal samples with volatile content as 18.99% and 27.52%, it increases first, then decreases and reincrease later, while for the coal samples with volatile content as 32.20% and 39.74%, it increases first and then decreases, but all the change rates of length of explosion flame of four groups of coal samples reach the maximum value when the particle diameter is in the range of 44 μm to 62.5 μm.