矿井封闭火区内气体运移规律

根据气体传质理论，煤矿井下火区封闭后，火区内生O2和有害气体运移平衡系统破坏，造成封闭火区内的O2浓度减少和CO等有害气体的积聚。当火区内化学反应达到平衡后，封闭火区内有害气体浓度逐渐减小，该过程是以气体分子在多孔介质中扩散为主要运移形式的质量传递过程。分析O2、CO通过封闭墙和煤层等多孔介质的扩散机理，并推导了有效扩散系数的计算公式。由公式计算封闭火区内O2降低5％的时间to和封闭火区内CO下降到0．001％的时间t，综合考虑封闭火区内的温度，计算出火区从封闭到启封的参考时间。

Gas transfer law in closed fire zone of a coal mine

According to the theory of mass transfer , after the fire-zone is closed under the coal mine, the balance system of the O2 and harmful gases migration in the fire-zone is destroyed, and the concentration of O2 decreases while the harmful gases such as CO accumulates in closed firezone. When the chemical reaction in the fire-zone gets into balance , the concentration of harmful gases decreases gradually .This process is the mass transfer by the form as gas molecule transfer in porous media .The article analyzes the diffusion mechanism of O2 and CO transferring in the porous media such as obturating wall and coal and deduces the calculating expressions of the effective diffusion coefficient . And works out the spent time t0 that the density of O2 in closed fire zone goes down to 5% and the spent time t that the density of CO in closed fire zone goes down to 0.001% . Then , considering the temperature in the closed fire zone, the paper works out the time from the time the fire zone is closed to the time the zone is opened.