非金属粉末对方管内瓦斯预混火焰传播的影响

Influences of nonmetallic powders on premixed methane-air flame propagation in square tube

为研究非金属粉末对管内瓦斯预混火焰传播的影响,选用煤粉和石粉2类煤矿井下常见粉末,采用微细热电偶、火焰传感器测试得出内铺2种粉末管内瓦斯火焰传播的瞬态温度、火焰阵面位置及火焰传播速度等参数,初步分析2种粉末影响瓦斯火焰传播机制的不同。实验表明:(1)煤粉能够加速管内瓦斯火焰的传播,而石粉则抑制管内瓦斯火焰的传播,但两者影响机制有本质不同;(2)内铺煤粉时,火焰温度瞬时值曲线呈现出明显的"双峰结构",反应区宽度增加,表明活性煤粉与瓦斯形成了瓦斯-煤粉复合火焰;(3)内铺石粉时,火焰温度值整体下降,温度半峰宽度变窄,说明撒布岩粉法能有效抑制瓦斯煤尘爆炸发生。

Two common powders in coal mine laneways, coal dust and rock dust, were spread evenly at the experimental tube bottoms, respectively. Subtle thermocouples and flame photoelectric sensors were adopted to obtain the premixed methane-air flame parameters including transient temperature, flame front position and flame propagating velocity in the tube. And the influencing mechanisms of the two powers on flame propagation were preliminarily analyzed. The experimental results show that the coal dust can accelerate the flame propagation in the tube, and the rock dust can suppress the flame propagation, but the mechanisms of acceleration or suppression are essentially different. When the coal dust is spread in the tube, the flame transient temperature curves at test points take on obvi- ous twin-peak structural waves and the reaction zones widen. It reveals that the methane-coal dust composite flame is formed between the reactive coal dust and the methane. When the rock dust is spread in the tube, the transient temperatures at test points all decrease, and the temperature half- peak widths narrow. It can explain that spreading rock powder in coal mine laneways can prevent or mitigate the methane-coal dust explosion hazards to a certain extent.