采空区漏风及残煤瓦斯涌出对采场气流的影响

Effect of Gob Air Leakage and Residual Methane Emission on Mining Stope Flow Field

在国内外文献调研的基础上,通过渗流力学、岩石力学、采矿工程等多学科交叉,采用理论分析、数值计算结合的方法,建立了煤矿采空区瓦斯流动数学模型。采用CFD技术对漏风流分布及瓦斯浓度场进行研究,获得了整个工作面上风流的速度和瓦斯浓度的分布情况,得到了漏入采空区和采空区返回工作面风流较为集中的范围,采空区漏风量与工作面风量之间的变化关系,漏风流速沿采空区衰减规律,确定了整个工作面上瓦斯浓度最高的地方为回风隅角,采空区内瓦斯浓度最高的区域也是整个采场瓦斯浓度最高的区域。通过对不同送风量的模拟研究,描述了瓦斯浓度的运移趋势,得到了回风隅角瓦斯浓度与送风量的关系,并且发现近风侧瓦斯浓度梯度较大,增大送风量能降低近回风隅角瓦斯浓度,但是会增加遗煤自燃的风险。揭示了采空区漏风和残煤瓦斯涌出对采场气体流动的影响规律。

Based on the investigation of the literatures at home and abroad,and according to the seepage mechanics,rock mechanics,mining engineering and other multi-disciplinary cross,we establish the coal mine goaf gas flow mathematical model with the method of combining theoretical analysis and numerical calculation. By the CFD technology,we study the leakage distribution and gas concentration field distribution of gas concentration and velocity about wind in working face,the scope of dissolute concentration in goaf and between goaf and working face,the relationship between goaf air leakage and air volume in working face,the decay law of air leakage rate velocity along goaf,and determine that the highest concentration of gas is return corner in entire working face,and the highest concentration of gas in goaf is also highest concentration of gas in entire scope. Through the simulation of different air supply volume,we describe the migration trend of gas concentration,the relationship between the concentration of gas and air flow rate of return corner,and also find that the gas concentration gradient is bigger in the air side,increasing the air supply volume can decrease the concentration of gas in return corner,but increases the risk of spontaneous combustion of remaining coal. This paper reveals the goaf air leakage and the residual coal gas emission of the influence law of stope gas flow.