采空区多参数气-固耦合渗流模拟

Numerical simulation of multi-parameters coupling seepage in goaf based on fluid-solid theory

针对由于采空区内非均匀孔隙介质的存在,造成采空区风流动态流动的复杂性,在渗流力学与气-固理论相结合的基础上,采用理论分析、软件模拟以及实例验证等方法,分析了采空区内孔隙度变化规律以及多参数渗流连续数学模型;基于高效的有限体积算法,进行了数值解算,并编制了模拟软件,研究结果表明:采空区内渗透率整体呈现"U型"筛分布,在进风口和回风口处最大,随着采空区深度的增加渗透率逐渐变小;压力呈"扇型"分布,在进风口处最大,随着向采空区延伸,压力变化逐渐趋近于零;采空区内渗流速度呈"弧型"分布,靠近工作面的区域漏风较强,随着向采空区延伸,漏风速度逐渐趋近于零;同时对模拟结果进行了三维和二维演示,使问题更清晰、直观明确,为辅助分析采空区瓦斯排放、自然发火、注氮灭火、大面积均压调压等诸多安全问题提供保障.

The airflow becomes very complex due to the existence of non-uniform pore medium in goaf.The multi-parameters dynamic mathematical model of air flow,the porosity distribution of caved rock and the seepage flow of non-uniform pore medium in goaf are investigated in this study using theoretical analysis,software simulation and example verification methods based on the gas-solid coupling theories and the permeation fluid mechanics.Subsequently,above numerical models are calculated using high-efficiency finite volume method(FVM),and the models are programmed.The results show that the permeability distribution appears in 'U' shape,a max permeability occurs at air inlet and outlet in goaf,and the permeability decreases along X axis.The air pressure distribution shows a 'fan' shape,the max pressure is at air inlet,the pressure is close to zero with the air moving into deep goaf.In addition,the seepage velocity distribution is in an 'arc' shape,and the air leakage is stronger near the working face than that in other places of the goaf.As all the modeling results can be shown in 3D and 2D,therefore,the distribution map can be clearly visualized.The study results provide a basis for understanding the real situation and preventing spontaneous combustion in goaf.