前进式U形通风采空区风流与自燃的数值模拟

NUMERICAL SIMULATION OF POROUS FLOW AND SPONTANEOUS COMBUSTION IN GOAF OF ADVANCING MINE U TYPE VENTILATION

基于渗流方程、多组分气体渗流-扩散方程和多孔介质渗流传热方程,建立前进式开采U型通风采空区自然发火模型.通过迭代方法计算沿空巷道的侧漏风量,以此边界条件数值模拟计算出前进式开采U型通风采空区的漏风规律;根据瓦斯-O_2-CO浓度和温度分布状态及其变化来描述自燃过程.在计算中,采空区非均质性按自然冒落考虑,兼顾瓦斯涌出对自燃的耦合作用;模拟得到,在前进式开采特有的3面漏风边界条件下,采空区自燃位置(最高温点)在开切眼冒落区进风一侧,自燃产生的有害气体和瓦斯随漏风流从回风边界渗出.在前进开采U型通风形式下,通风量在到达工作面时衰减很大,因此,前进开采布置一次推进距离不易过大;解决好沿空留巷的封堵材料和正确的堵漏措施,是保证前进式开采顺利进行的技术关键.

Based on the non-isotropic porous medium, the gas transfusion-diffusion equation and the porous medium transfusion synthesis heat transfer equation, a coupling numerical model of spontaneous combustion in goaf is established, the solution is obtained with the windward finite element method software （G3）. The computation results are displayed by graphics. The advancing mine U-type ventilation is simulated for its leak tendency of gas, oxygen, CO and for the temperature distribution. Two kinds of ventilation are shown to be able to avoid picking the mined-gob area gas by the working face. The computation considers the goaf＇s anisotropy and shows that the gas gushes out with the spontaneous combustion coupling function and the goaf gas conduction current produces massive leaks.