利用Fluent软件,对采空区瓦斯为采空区整个区域涌出和上、下临近层及底板遗煤处同时涌出两种情况下的流场进行了数值模拟,并分析了采空区瓦斯体积分数及自燃带分布规律。结果表明:当采空区整个区域瓦斯涌出时,采空区瓦斯体积分数由底板到顶板垂直方向上呈逐渐升高的趋势;当上、下临近层及底板遗煤处瓦斯同时涌出时,采空区瓦斯体积分数在靠近底板和顶板位置处较高,中间区域处较低。与采空区整个区域瓦斯涌出相比,当上、下临近层及底板遗煤处瓦斯同时涌出时,在采空区底板处,自燃带更靠近工作面;在采空区底板和顶板中间位置处,自燃带远离工作面;在采空区顶板处,自燃带位置几乎没有变化。
This paper is engaged in a simulated study of the impacts of the gas outburst location on the gas concentration distribution and its spontaneous combustion zone in the airflow field in the goaf. Theo- retically speaking, the location of gas outburst has a significant effect on the goaf air ventilation and the gas distributive regulation, which helps to determine the gas outburst location as a proper position near the actual outburst point than it to be searched from the entire goaf area. For our research purpose, we have first of all established a 3-D physical model v/a a software named Gambit, and, then, begun to simulate the air ventilation field of two different kinds of gas outburst position, of which the uniform outburst takes place from the entire goaf zone and the upper and lower adjacent layers and the fallen coal near the floor evenly at the same time, and, finally, we have ana- lyzed the distribution regularity of the gas concentration and the spon- taneous combustion zone by the said software Fluent, which can be expected to provide us with the following conclusions : ( 1 ) When the gas bursts out evenly from the entire goaf zone, its concentration tends to rise gradually from the bottom to the top. However, if the gas evenly bursts out from the upper or lower adjacent layers with the coal seam collapsed near the floor at the same time, the gas concen- tration in the goaf would be higher near the bottom or near the top, which is lower in the middle area. (2) As compared with the uniform outburst from the entire goaf region, when the gas rushes out evenly from the upper and lower adjacent layers and falls near the floor at the same time, the spontaneous combustion zone would move closer to the working face at the bottom. In the middle area between the bottom and the top of the coal seam, the spontaneous combustion zone tends to be away from the working face. But at the top, there would no change at all with the gas points burst out in the spontaneous combus- tion.