采空区气体微流动场模拟研究

Simulation study on gas micro-flow field in goaf

为分析在短期内消除采空区自燃火灾气体对工作面影响,进而确定抽放参数,针对霍州煤电集团回坡底煤矿采空区局部自燃火源点的火灾情况,提出了用地面钻孔抽放采空区自燃火灾气体,使其避免流向工作面的方法。通过XK型煤自然发火试验台及XKS程序升温试验台进行了试验分析,推出煤自燃表面分子结构模型。以多孔介质流体动力学以及能量守恒定律为理论基础,以陶粒为相似模拟材料对采空区气体微流动进行了多孔介质相似模拟以及数值模拟研究。结果表明,示踪气体从工作面流入采空区,最终在采空区深部聚集,且在射流惯性作用下,进风侧聚集明显,回风侧因为卷吸作用,气体浓度较低。

In order to eliminate the influence of spontaneous combustion gas in goaf on working face as soon as possible,and then determine the drainage parameters,according to the fire situation of local spontaneous combustion point in goaf of Huipodi coal mine,the method of pumping spontaneous combustion gas in goaf by ground drilling to avoid flowing to working face is put forward.Based on the experimental analysis of XK coal spontaneous combustion test bed and XKS temperature programmed test bed,the surface molecular structure model of coal spontaneous combustion was established.Based on the fluid dynamics of porous media and the law of energy conservation,the similar simulation and numerical simulation of gas micro-flow in goaf were carried out with ceramsite as the similar material.The results show that the tracer gas flows into the goaf from the working face,and finally accumulates in the deep part of the goaf.At the same time,under the action of jet inertia,the concentration of tracer gas is obvious on the inlet side,and the concentration of tracer gas is low on the return side because of entrainment effect.