易自燃采空区瓦斯与火灾共治数值模拟

Numerical Simulation on Gas and Fire Control in Spontaneous Combustion Gob

易自燃煤层采空区瓦斯和火灾综合防治是煤矿亟待解决的难题,基于多孔介质渗流理论,把采空区渗透系数以及瓦斯涌出源项看成随采空区位置变化的量。建立采空区气体流动的质量方程、动量方程、组分传输方程以及能量守恒方程,应用fluent软件模拟采空区在不同工作面供风量、不同抽放情况下采空区流场分布,得出工作面风量与氧化带宽度的拟合关系式。指出瓦斯抽放对采空区瓦斯浓度分布以及氧化带宽度影响比较显著;结合现场观测数据,表明数值模拟的可靠性。通过数值模拟,可以得出采空区不同瓦斯治理参数与氧化带宽度的对应关系,为煤矿采空区瓦斯和火灾合理防治提供依据。

Integrated control of gas and fire is a difficult problem which demands prompt solution in spontaneous combustion gob,based on seepage theory in porous zone,permeability coefficient and gas emission source term in gob were regarded as the value that changes with the location of gob.The gob gas flow equations of mass conservation,momentum conservation,component transfer and energy conservation were established.Flow field distribution was simulated in the condition of different face air volume and gob drainage by fluent software,and the fitting relationship of face air volume and oxidation width was reached.It is pointed out that the gob gas drainage has significant effect on the distribution of gas concentration and oxidation width.Combined with the observation data in coal mines,the reliability of numerical simulation is verified.By numerical simulation,the corresponding relationships of gas control parameter and oxidation width can be drawn,which can provide a reasonable basis for the prevention of gob gas and fire.