回采工作面高位钻孔抽采瓦斯效果数值模拟及方案优化

以提高瓦斯抽采效果为目标， 某矿Ⅲ4423工作面为研究对象，采用理论分析、 数值模拟、现场试验等研究方法，研究了顶板高位钻孔条件下瓦斯抽采的主要技术参数 ，数值模拟出高位钻孔抽采瓦斯前采空区的瓦斯分布情况与运移规律，以及负压分别为 8、10 kPa时的高位钻孔瓦斯抽采效果。依据瓦斯流动“O”型圈理论与FLUENT数值模拟 分析，优化设计高位钻孔抽采瓦斯工艺参数并进行现场试验。结果表明:当高位钻孔抽 采负压为8 kPa、终孔位置调整到采空区裂隙带回风巷侧15~35 m范围内时，高位钻孔抽 采瓦斯效果最佳，采空区内瓦斯最高浓度明显降低，单个钻场最大抽采瓦斯量为19 821.74 m3，钻孔瓦斯浓度稳定在 20%~30％之间，最大值达到50％，实现了工作面有效 治理瓦斯和安全生产的目标。

Numerical simulation and scheme optimization on gas drainage through high level borehole in working face

To improve the effect of gas drainage, taking the Ⅲ4423 working face in a mine as the research object, the main technical parameters of gas drainage under the condition of high level borehole in roof were studied using the theoretical analysis, numerical simulation and field test methods. The gas distribution situation and migration laws in the goaf before the high level borehole gas drainage were simulated, as well as the gas drainage effect through high level borehole under the negative pressure of 8 kPa and 10 kPa respectively. According to the O-shape circle theory of gas flow and FLUENT numerical simulation, the technological parameters of gas drainage through high level borehole were optimized and designed, and the field test was carried out. The results showed that the gas drainage effect through high level borehole was the best when the negative pressure was 8 kPa and the position of final hole was adjusted into the 15-35 m range on the side of return airway for the fracture zone of goaf. The max-imum concentration of gas in the goaf decreased significantly, the maximum amount of gas drainage in single drill field was 19821.74 m3, and the gas concentration of borehole kept stable at 20%-30%, with the maximum value of 50%, so the targets of effective gas control and work safety in working face were realized.