采空区渗透率对瓦斯运移影响的模拟研究

Simulation Study on the Influence of Permeability on Gas Migration in Gob

根据计算流体力学基本理论,利用Fluent软件,对采空区渗透率为均匀分布、分段均匀分布、连续分布、"O"型连续分布4种不同分布情况下采空区瓦斯运移规律进行数值模拟。当渗透率均匀分布时采空区漏风较少,高浓度瓦斯分布靠近工作面;当渗透率分段均匀分布时,在采空区中有2条跳跃的瓦斯沟壑;当渗透率连续分布时,采空区漏风较多,高浓度瓦斯分布靠近采空区深部;当渗透率"O"型连续分布时,采空区漏风最多。结果表明,当渗透率不同分布情况下采空区漏风和瓦斯分布有很大差别。因此,为了得到更符合现场实际情况的瓦斯运移规律,在模拟采空区瓦斯运移规律时需要描述更能如实反映采空区煤岩冒落规律的渗透率分布。

According to CFD basic theories,numerical simulations on gas migration in gob are respectively conducted by using Fluent software under different distributions of gob permeability,such as uniform distribution,segmented uniform distribution,continuous distribution and ＂O＂-typed continuous distribution.When the permeability is evenly distributed,the air leakage in goaf is less and high-concentration methane distributions are near the face.When the permeability is piecewise evenly distributed,there have two bouncing gas ravines in mined-out.When the permeability is continuously distributed,the air leakage in goaf is bigger and high-concentration methane distributions are near the deep of the goaf.When the permeability is ＂O＂-typed continuously distributed,the air leakage in goaf is the most.The results show that the air leakage and gas distribution in gob are very different under different permeability.Therefore,in order to get more actual rules of gas migration,the permeability distribution in mined-out areas of coal and rock falling should be described as carefully as possible when simulation is conducted.