移动坐标下掘进工作面瓦斯涌出的无因次分析

Dimensionless analysis on gas emission law around tunneling face

为研究厚煤层中巷道掘进时的瓦斯涌出规律,建立了移动坐标下的掘进工作面瓦斯涌出数学模型,通过引入巷道半径与长度准数、压力准数、掘进速度准数等无因次参数,将模型无因化,利用有限体积法对无因次方程进行离散,然后采用迭代法求解,并编制解算程序。解算结果表明,巷道周围煤体中的无因次瓦斯等压线呈子"弹头"状分布;随着速度准数的增大,无因次瓦斯压力及含量的分布等值线都向煤壁收拢,煤壁附近的无因次瓦斯比流量显著增大,从而导致无因次瓦斯涌出量急剧上升,且掘进工作面处的无因次涌出量增速更大。

In order to study the gas emission law when the roadway was excavated in thick coal seam,a gas emission mathematical model of heading face under the moving coordinates was established,and then the model was made dimensionless by the dimensionless parameters of length,pressure and driving speed. The dimensionless equations were discretized by Finite Volume Method,and the calculation was conducted by iterative method. The results of the calculation show that the dimensionless gas pressure contour around roadway distributes like warhead shape. With the increase of speed dimensionless parameter,the contour distribution of dimensionless gas pressure and content tuck to the coal wall,thus the dimensionless gas ratio flow near the coal wall increases sharply,which leads to dimensionless gas emission significantly increases.