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 According to the design of goaf gas discharge in Sihe mine, the authors established the finite element numerical model for infiltration flow and diffusion in heterogeneous goaf. It can visually depict the gas emission course in goaf, the gas distribution rule and the hydrodynamics principle for gas accumulation in return corner of a goaf. The simulation result shows that by using return connected lane for air leakage diversion and gas discharge in proper order, we can reduce gas concentration in return corner... According to the design of goaf gas discharge in Sihe mine, the authors established the finite element numerical model for infiltration flow and diffusion in heterogeneous goaf. It can visually depict the gas emission course in goaf, the gas distribution rule and the hydrodynamics principle for gas accumulation in return corner of a goaf. The simulation result shows that by using return connected lane for air leakage diversion and gas discharge in proper order, we can reduce gas concentration in return corner greatly, at the same time, if the method is used properly, we may also fully restrain the gas in the goaf from swarming into working faces and reduce distributed air quantity of drainage roadways. To the gas discharge in goaf of high gas mines, the authors bring forward a design scheme:"discharging and drawing out gas while excavating coal", which can control goaf gas synthetically, and the optimum position range of gas drainage, drainage flux, and the lowest critical limit of the indicating air quantity are also given.  以寺河矿采空区瓦斯抽放设计为例,建立了非均质采空区渗流扩散的有限元数值模型,直观地描绘了采空区瓦斯涌出过程、瓦斯分布规律及其在采空区回风隅角瓦斯积聚的流体力学原理。模拟结果表明,在工作面后方利用回风联络巷依次进行漏风导流和瓦斯抽放,可大幅度降低采空区回风隅角瓦斯浓度;同时漏风导流可以充分抑制采空区瓦斯涌入工作面,并能够降低抽放巷道的配风量。针对高瓦斯矿井采空区瓦斯排放问题,提出了"边采边抽边排"的综合治理采空区瓦斯的设计方案,给出了瓦斯抽放最佳位置范围、抽放流量和导流风量最低临界限。  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... 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 inverselyproportional 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.  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著的反比关系,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.  The model of gas effusion and air exchange in inhomogeneous goaf was established based on twophase miscible gas seepagediffusion equation. The model is solved by means of upwind Galerkin numerical method, and the basic fluid mechanics principle of the gas transport and distribution is described by means of visualization way. On the basis of mechanical disposal,the gas effusion in the goaf with gastight roof and floor is treated as twophase gas miscible flow;but the calculation of the flow pattern (velocity... The model of gas effusion and air exchange in inhomogeneous goaf was established based on twophase miscible gas seepagediffusion equation. The model is solved by means of upwind Galerkin numerical method, and the basic fluid mechanics principle of the gas transport and distribution is described by means of visualization way. On the basis of mechanical disposal,the gas effusion in the goaf with gastight roof and floor is treated as twophase gas miscible flow;but the calculation of the flow pattern (velocity field) is solved by regarding it as a seepage problem of incompressible gas. So it can avoid the error and distortion from incompressible gas seepagediffusion model in calculating gas distribution because of super saturation solution in the result. The gas source in goaf is described by negative exponential attenuation function. An example provided in the case of wind is increased,which shows the dynamical balance feature between the air pressure in working face and gas pressure in the goaf. Compared with the result calculated as singlephase flow,the gas distribution results between them are almost the same when the speed of air is relatively high,if not,there is a large difference between the results. The critical air speed when the difference appears in the example is 0.091m/min,but the gas distribution is significantly different in the deep part of the goaf.  基于两相混溶气体渗流–扩散方程,建立了非均质采空区瓦斯涌出与风流交换的模型,用迎风式Galerkin数值方法求解,以可视化方式直观描绘了回采中采空区瓦斯的运移与分布的流体力学原理,采空区瓦斯源用负指数衰减函数描述。在力学处理上,对不透气顶、底板采空区的瓦斯涌出用可压缩两相气体混溶来考虑,流态(速度场)计算则用不可压缩气体渗流求解,由此可克服了以往采用不可压缩气体渗流–扩散模型计算瓦斯分布结果中因“超饱和”解所带来的误差和失真问题。给出增大风量后瓦斯分布的算例,由此反映出工作面风压与采空区内部瓦斯压力的动态平衡性。与单相流计算结果对比,在风流流速相对较高的情况下,两者的瓦斯分布结果基本一致,反之则差别很大,算例中开始出现差别的临界风速为0.091m/min,在采空区深部处瓦斯分布显著不同。   << 更多相关文摘 
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