突出过程中煤–瓦斯两相流运移的物理模拟研究

Physical simulation of coal-gas two-phase flow migration in coal and gas outburst process

为了探讨煤与瓦斯突出过程中的煤–瓦斯两相流冲击破坏动力学行为,利用自主研发的多场耦合煤矿动力灾害大型物理模拟试验系统开展了突出过程中煤–瓦斯两相流运移规律物理模拟试验研究。结果表明:突出煤粉在高速气流作用下自工作面抛出,呈射流状,随着距离的增加,固相流扩散为栓塞流,沉降量随之增大,从而主要聚集在巷道末端;试验相对突出强度为10%,突出煤粉中绝大部分为粒径小于0.150 mm的煤粉,煤体破碎程度较高;突出启动后,高压气流携带大量煤粉从煤层中喷射而出,形成较强的冲击力,近突出口区域冲击力反复升降,表明突出过程具有阵发性;煤–瓦斯两相流运移过程中瓦斯完全膨胀形成冲击力陡增区,冲击力沿巷道呈波动式分布,距突出口4 944 mm处峰值冲击力最大,随后沿巷道呈震荡衰减变化趋势。

To investigate the impact feature and dynamic behavior of coal-gas two-phase flow in the process of coal and gas outburst,physical simulation test of coal-gas two-phase flow was carried out by multi-field coupling testing system for dynamic disasters in coal mine.The results show that the outburst pulverized coal is thrown from the working face in a jet shape due to the high-speed airflow.As the distance increases,the solid-phase diffuses and converts into the plug flow,and the deposition amount increases accordingly and concentrates at the end of the roadway.The relative intensity of the outburst is 10%,and pulverized coal with a diameter of less than 0.150 mm accounts for the main part of the outburst coal which indicates that the fragmentation degree of pulverized coal is high.While the outburst is triggered,a large amount of pulverized coal is ejected by the high-pressure airflow from the coal seam to create a large impact force.The impact force near the outburst orifice changes repeatedly,which indicates that the outburst process presents paroxysmal characteristics.In the motion process of two-phase flow,the gas expands completely to form a steeply increasing impact zone.The impact force reaches the largest at 4 944 mm from the outburst orifice and then attenuates along the roadway.