掘进工作面瓦斯动态涌出规律数值模拟研究

Numerical simulation study of gas dynamic emission laws of driving face

为研究掘进过程瓦斯涌出规律,基于有限体积法的C—N格式离散方法,编制程序并对移动掘进工作面巷道周围瓦斯压力分布、煤体透气性变化及瓦斯涌出速率变化情况等进行了数值模拟。结果表明,随着工作面向前掘进,掘进工作面一定区域内巷道围岩煤体瓦斯压力分布向前移动。掘进过程中巷帮瓦斯压力存在转折点,转折点之前的瓦斯压力梯度减小速率大于转折点之后的瓦斯压力梯度。不同掘进长度下巷道沿程煤壁瓦斯涌出速率曲线基本一致,且瓦斯涌出速率较大区域主要集中在掘进头巷道部分。掘进过程中瓦斯涌出速率呈锯齿状变化,每一个掘进循环中掘进头巷道部分刚被掘开时瓦斯涌出异常剧烈。随着掘进巷道增长,瓦斯涌出速率总体上逐渐增大。

In order to study gas emission laws during driving process, based on C N discretization method of finite volume method, the authors programmed to numerically simulate gas pressure distribution, coal mass permeability and gas emission rate change around moving driving face. The simulation results indicated that with the heading of driving face, gas pressure distribu- tion of roadway surrounding rock and coal in certain region was moving forward. Drift gas pressure had turning point during driv- ing process and the decreasing rate of gas pressure gradient before turning point was higher than that after turning point. Roadway with different heading length shared the gas emission rate and areas with high gas emission rate were gathered at heading road way. In the driving process, the gas emission rate was serrate-shaped. Gas emission was extremely intense when every heading roadway was freshly driven. Generally, gas emission rate increased gradually with the driving process.