水平管内不同煤质煤尘爆炸火焰传播特性实验研究

为研究水平管道空间不同煤质煤尘爆炸火焰传播特性，选取褐煤、长焰煤、不粘煤、气煤4种煤尘，对爆炸火焰焰峰特性、火焰加速传播特性、火焰传播距离与持续时间展开研究。研究结果表明:褐煤在500 ms内焰峰的形状由尖锐向平滑再向钝化不断演变，长焰煤与不粘煤在375 ms时焰峰前端出现明显焰体分离现象，分析认为这与管体冷壁效应、空间尺度效应及空间氧气消耗直接相关；气煤在375 ms时焰峰出现大面积火焰碎纹，说明气煤爆炸火焰猛烈传播的持续时间相对较短，整体爆炸强度相对较弱；褐煤与长焰煤爆炸火焰存在2次间断性加速，分析认为这与管体空间受限、常温管壁散热、局部助燃氧气瞬间不足等因素有关；褐煤在爆炸后400～600 ms内火焰2次加速完全，火焰传播距离达740 mm，明显大于长焰煤、不粘煤与气煤，说明低变质褐煤爆炸火焰持续时间更长，火焰传播距离更远且传播更剧烈；虽然气煤火焰最远传播距离比长焰煤大30 mm，但由于气煤火焰在375 ms左右出现大片火焰碎纹，因此气煤整体的爆炸强度小于长焰煤。

Experimental study on flame propagation characteristics of coal dust explosion under different coal properties in horizontal tube

In order to study the flame propagation characteristics of coal dust explosion under different coal properties in the horizontal pipeline space, four kinds of coal dusts including lignite, long flame coal, non caking coal and gas coal were selected, and the flame peak characteristics, flame acceleration propagation characteristics, flame propagation distance and duration of the explosion flame were studied. The results showed that the shape of flame peak evolved continually from sharp to smooth and then to passivation within 500 ms for the lignite. The long flame coal and non caking coal presented the obvious flame separation at the front end of flame peak at 375 ms, which was directly related to the cold wall effect of tube, spatial scale effect and spatial oxygen consumption. The flame crackle with a large area appeared in the flame peak at 375 ms for the gas coal, which was related to the relatively shorter duration of the violent propagation of the explosion flame and the relatively weaker overall explosion intensity. There were two intermittent acceleration of explosion flame for the lignite and long flame coal, which was related to the factors such as the limited space of tube, heat dissipation of tube wall at the normal temperature, instantaneously insufficient local combustion supporting oxygen, etc. The lignite had a complete secondary acceleration of the flame within 400-600 ms after the explosion, and the flame propagation distance was 740 mm, which was obviously larger than those of long flame coal, non caking coal and gas coal, it indicated that the lignite with low metamorphic degree had the longer duration of explosion flame, the longer flame propagation distance and the more violent propagation. Although the farthest propagation distance of the gas coal flame was 30 mm larger than that of the long flame coal, the overall explosion intensity of gas coal was less than that of long flame coal due to the large flame crackle of the gas coal flame around 375 ms.