尾巷对采空区煤自燃影响的数值模拟研究

Numerical Simulation of Effect of Tail Roadway on Coal Spontaneous Combustion in the Goaf

为了研究尾巷对采空区煤自燃的影响,建立了带有尾巷的三维采空区的几何模型,利用UDF编写采空区碎胀系数和孔隙率的分布函数,从尾巷的联络巷间距和回风巷与尾巷之间的压差两个方面进行了模拟.结果表明:尾巷的联络巷间距对采空区自燃有重要的影响,间距增大,采空区自燃带的宽度也增大,越靠近回风侧,宽度增加越快;回风巷与尾巷之间的压差对采空区自燃带的宽度影响不大,但对尾巷回风量有重要影响,压差越大,尾巷回风量也越大.在高瓦斯易自燃煤层应用尾巷时,只有使尾巷的联络巷间距小于无尾巷时的采空区散热带的宽度,并在停产期间立即封闭尾巷,才不会增加采空区遗煤自燃的危险性.

In our study,we establish 3-D geometric model to research effect of tail roadway on coal spontaneous combustion in the goaf.Using the UDF,we compile the distribution function of goaf bulking factor and interstice ratio,and simulate the intervals between crossheadings as well as pressure difference across the return airway and tail roadway.The results indicate that 1） the intervals between crossheadings have an important effect on coal spontaneous combustion in the goaf;2） with the increase of intervals,the width of combustion zone in the goaf increase also;3） the closer it is to the air return,the faster its width increases;4） the pressure difference between return airway and tail roadway has only a little effect on the width of combustion zone in the goaf,but it has a great effect on the air volume in air return way;and 5） the greater the pressure difference is,the larger the air volume of tail roadway is.When the spontaneous combustion coal with high gas have a tail roadway,only when the intervals between crossheadings is less than the width of heat diffusing zone in the goaf and seal the tail roadway immediately during the period of cease production,will the risk of spontaneous combustion not to increase.