采空区开区移动瓦斯抽放的数值模拟

针对我国高瓦斯矿井采空区瓦斯抽放的现状，强调了在工作面后方“边采边抽”的开区移动瓦斯抽放方法，以提高资源回收减少大气污染与瓦斯治理的双重效益．建立了非均质采空区瓦斯渗流--扩散的数值模型，模拟了瓦斯在采空区中的涌出、分布及积聚的流体力学原理．模拟表明，抽放流量与采空区瓦斯涌出量和抽放瓦斯浓度均呈显的反比关系，且抽放的纯瓦斯量基本保持恒定，结论与采空区瓦斯持续稳定释放的客观性完全一致；抽放口位置越深入采空区，瓦斯绝对涌出量略有降低，抽放浓度越高．由此确定了抽放口的最佳位置和抽放流量．结合实例，利用联络巷进行瓦斯抽放，可获得高于40％浓度的瓦斯，理论抽放效率在70％以上，若配合以漏风导流，可彻底抑制瓦斯涌入工作面，并降低配风量。

Numerical Simulation of Gas Drainage During Open Region Movement in Goaf

Considering the current state of gas drainage in goafs of highly gassy mine in China, the "draining while mining" gas drainage method during open region movement behind working faces was emphasized to raise the resource recovery, decrease atmosphere pollution and implement gas control. A numerical model for infiltration flow and diffusion of gas in heterogeneous goaf was established. It can be used to simulate gas emission, gas distribution rule and the hydrodynamics principle for gas accumulation. According to the simulation results, there are obvious inversely-proportional relationships between drainage flux as well as gush quantity of gas in goaf and gas drainage concentration, and the net gas drainage quantity is almost a constant. The conclusion is consistent with the objectivity that the release of gas in goaf is steady. With the positions of drainage bores goes deep into goaf, the absolute emission quantity of gas decreases slightly, and the drainage concentration is higher. Therefore, the optimal positions of drainage bores and drainage flux can be determined. According to examples, while using crossheadings to drain gas, the concentration of drained gas can reach 40 percent or higher, and the theoretical drainage efficient can reach 70 percent or higher. If air leakage fluid diversion is used, we can restrain gas from swarming into working faces, and the distributed air quantity can also be reduced.