U型工作面上隅角埋管瓦斯抽采数值模拟研究

Numerical simulation on gas drainage with buried pipe in upper corner of U-type working face

传统的U型通风工作面上隅角瓦斯积聚现象经常出现,严重制约着矿井正常生产能力的有效发挥,对矿井安全生产造成重大威胁。基于前人对采空区非均质多孔介质气体运移理论的研究,采用Fluent软件数值模拟研究了U型和上隅角埋管条件下U型通风系统的静压力场和瓦斯浓度场。研究结果表明:在相同的模型参数条件下,U型通风容易造成上隅角瓦斯积聚,上隅角瓦斯超限问题十分严重;采空区5m处埋管,治理上隅角瓦斯积聚的效果欠佳,达不到安全开采的条件;15m处埋管可以较好的解决上隅角瓦斯超限问题,工作面没有出现瓦斯积聚现象,工作面和回风巷的瓦斯浓度始终处于1%以下;25m处埋管的效果与15m基本相同,没有表现出更好的瓦斯治理效果。综合数值模拟的结果,确定了上隅角埋管抽放采空区瓦斯的理想抽放位置为距离地板垂高1.2m、沿走向深入采空区15m处。

It is known that the problem of gas accumulation in the upper comer occurs frequently in coal faces of traditional U-type ventilation system. In order to make a comparative analysis of gas migration and distribution regu- larity in the gobs by using the different models, based on the heterogeneous and porous medium theory, the physical models of gobs by using the U-type and gas drainage with buried pipe in U-type ventilation manners were estab- lished, and a numerical simulation model on the air flow was built to look into the gas flow field more profoundly in the gobs by using U-type and gas drainage with buried pipe in U-type ventilation via the Fluent software. After that, the district distribution solution for gas mole fraction was given as the graphics mode with the air flow of gob with the different position of buried pipe. By analyzing the numerical simulation results, it showed that： with the same gas emitting and air-supplying volume in the working serious in U-type ventilation , while problem face, the problem of gas accumulation in upper comer angle was obtained the alleviation by takin~ ~as drainaze with buried nine which position of buried pipe was five meters deep to gob area, but still not worked. When the pipe position was fif- teen meters deep to gobarea, the effect for gas drainage was best and the disallowed gas concentration in the upper corner and return airway was reduced to 1%. Furthermore,the pipe position was twenty five meters, the effect for gas drainage was not better than fifteen meters. Therefore, it can be concluded that the optimal parameter of pipe position was 1.2 meters high from the ground and fifteen meters deep to gob area.