采空区不同瓦斯抽采方法与自燃合理平衡的数值模拟

 采空区不同瓦斯抽采方法与自燃合理平衡的数值模拟

（1．辽宁工程技术大学安全科学与工程学院，辽宁阜新123000；

2．辽宁工程技术大学矿业技术学院，辽宁葫芦岛125105）

摘要：为了研究和解决西铭矿在生产中由于瓦斯抽采方法的不同可能引起采空区自燃以及瓦斯爆炸等重大安全隐患问题，构建了高位巷、埋管和高低位钻孔瓦斯抽采方法下的非均质多孔介质三维模型。利用非线性渗流定律、通用控制方程和自定义的函数进行解算，结果表明：高位巷、高低位钻孔抽采流量与抽采氧气浓度近似呈正比函数关系，埋管抽采流量与氧化带宽度呈指数函数关系；高位巷、高低位钻孔随着抽采流量的增加抽采效率反而降低，抽采总量增加，埋管抽采位置在距工作面35m处、抽采流量为20m³/min能很好解决上隅角瓦斯超限问题。根据模拟结论：采用立体联合瓦斯抽采方法既能满足抽采要求又能有效控制采空区自燃现象。

关键词：不同瓦斯抽采方法；采空区；自燃；三维模型；数值模拟

中图分类号：X936    文献标志码：A    doi: 10. 11731/j．issn. 1673-193x．2015. 08. 005

  Numerical simulation on reasonable balance between different gas drainage methods and spontaneous combustion in gob area

 WANG   i-renl ,ZHANG Yingl ,HUANG Gel ,HAO Chao-yul ,ZHANG Chun_hua2

 ( 1.  College of Safety Science and Engineering, Liaoning Technical University, Fuxin Liaoning 123000, China;2. Safety Engineering Department of Ming Industry Technology College, Liaoning Technical University, Huludao Liaoning 125105 ,  China)

Abstract: In order to study and prevent the potential safety problems of spontaneous combustion and gas explosion in gob area caused by different gas drainage methods in Ximing coal mine, a three-dimensional numerical model of heterogeneous porous media was established for simulating gas drainage with different methods including high level entry method, buried pipe method, and high and low level borehole method.  The nonlinear percolation law, gener-al control equations and the self-defined functions were used for resolving the model. The results showed that: the gas drainage flow rate is directly proportional to the concentration of extracted oxygen when the high level entry and high and low borehole methods are used, while an exponential function relationship between gas drainage flow rate and width of oxidation zone appears when the buried pipe method is used. With the high level entry and high low borehole methods, the incremental drainage efficiency reduces when the drainage flow rate increases, but the total drainage amount increases.  Gas exceeding limits in the upper corner can be prevented fairly well when the drainage position is 35 m away from the working face, at the flow rate of 20m³/min with buried pipe method.  The three-di-mensional combined gas drainage method can not only meet the requirements of drainage, but also control the spon-taneous combustion in the gob area effectively.

Key words: different gas drainage methods; gob; spontaneous combustion; three-dimensional model;numerical simulation

结论

1)现场实际调节抽采流量工程大、困难多。运用Fluent软件可以方便、快捷的模拟不同瓦斯抽采下合理的瓦斯抽采流量、瓦斯浓度和氧浓度的三维立体分布图，并较二维图更真实的反应现场情况。

    2)结合西山煤电集团西铭矿48205工作面实际情况，利用理论分析，明确了瓦斯抽采诱导遗煤自燃致灾的关联因素，通过模拟结果表明，对采空区灾害的控制，一味的追求大流量反而适得其反，得出了高位巷、埋管和高低位钻孔（共20个钻孔）的最佳抽采流量都为20m³/min。

    3)基于数值分析，选择“高位巷+埋管”立体联合共同抽采的方式，有效控制了瓦斯超限与遗煤自燃的威胁，为现场提供了理论基础和实践指导。

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