高位抽采下近距离煤层采空区复合致灾数值模拟研究

Numerical Simulation Study on Coupling Hazard in Gob of Contiguous Seams in Condition of Gas Drainage in Upper Roadway

从煤矿井下安全生产的角度出发,以西铭矿近距离煤层采空区的特点为例,建立了一种高位巷抽采下近距离煤层采空区三维模型。通过Ansys Fluent对采空区气体流动控制方程和非均匀瓦斯释放源项、浮煤耗氧源项进行三维稳态解算发现,随着高位巷抽采流量的不断增大,抽采瓦斯总量逐渐升高,抽采浓度和抽采效率逐渐降低,在抽采流量升至30 m3/min后,所有变化趋势变缓。上部邻近煤层高氧浓度富集区不断增大,下部遗煤处无明显变化。研究表明,采用抽采流量都为20 m3/min的高位巷与上隅角埋管相结合的瓦斯抽采方法能有效控制采空区复合致灾隐患。

From the perspective of coal mine production safety,taking characteristics of contiguous seams gob in Ximing coal mine as the example,3D numerical model of contiguous seam gob is built for simulating gas drainage in highly-located roadway. Gas flow equation,inhomogeneous gas release source item and float coal consumption of oxygen source term in gob are calculated though Ansys Fluent software. The calculated results show that with the increase of the gas drainage flow rate,the total amount gradually increases,while the concentration of gas drainage and the drainage efficiency gradually reduces. And all the change trends slow down after the gas drainage flow rate increases to 30 m^3/ min. The high oxygen concentration region increases continuously in the upper of contiguous coal seam and there is no obvious change in the bottom coal. The results show that coupling hazard in gob can be effectively controlled by using the gas drainage method of high level entry and buried pipe at flow rate of 20 m^3/ min.