空气幕对采空区漏风和上隅角瓦斯积聚影响研究

Study on the Effect of Air Curtain on Air Leakage in Goaf and Gas Accumulation in Upper Corner

为有效防治采空区漏风和上隅角瓦斯积聚,提出在上隅角处布置空气幕系统,通过形成空气幕墙以阻隔采空区回风侧漏风,同时对上隅角处进行加压,达到均压堵漏效果。利用COMSOL数值模拟软件研究空气幕在不同射流宽度、射流速度和射流角度参数下对采空区漏风、氧化带面积、上隅角瓦斯浓度和采场能位分布的影响。结果表明:随着空气幕射流速度和宽度增大,采空区漏风量和上隅角瓦斯逐渐减少,氧化带面积先减小后增大,大宽度低流速空气幕对横向风流阻挡能力要优于小宽度高流速空气幕;空气幕方向由垂直向水平方向增大射流角度能有效减少采空区漏风和氧化带面积。综合考虑空气幕对采空区漏风、氧化带面积、上隅角瓦斯浓度的影响,空气幕在射流宽度为25 cm、射流角度为20°~30°、射流速度为7~8 m/s时效果最佳;空气幕可以吹散上隅角瓦斯,将瓦斯封闭在采空区内部,有效防治上隅角瓦斯积聚,同时可在采空区内部形成均压效果,有效减少采空区回风侧漏风。

In order to effectively prevent air leakage in goaf and gas accumulation in upper corner, it is proposed to install an air curtain system at the upper corner. Through forming an air curtain wall to block air leakage on the return side of goaf and applying pressure to the upper corner, an uniform-pressure plugging effect can be achieved. The effects of air curtain on air leakage, oxidation zone area, gas concentration in upper corner and distribution of energy levels in the mining area with different jet widths, jet velocities and jet angles were studied by COMSOL numerical simulation software. The results show that with the increase of jet velocity and width of air curtain, the air leakage in goaf and the gas in upper corner decrease gradually, and the area of oxidation zone decreases first and then increases. The ability of a wide and low velocity air curtain to block lateral airflow is superior to that of a narrow and high velocity air curtain. Increasing the jet angle from vertical to horizontal in the direction of the air curtain can effectively reduce air leakage and oxidation zone area in the goaf. Taking into account the influence of air curtains on air leakage, oxidation zone area, and gas concentration in the goaf, the air curtain has the best effect when the jet width is 25 cm, the jet angle is 20°-30°, and the jet velocity is 7-8 m/s. Air curtains can blow away the gas in the upper corner, seal the gas inside the goaf, effectively prevent the accumulation of gas in the upper corner, and form an uniform-pressure plugging effect inside the goaf, which can effectively reduce air leakage on the return side of the goaf.