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为了研究煤层瓦斯流动过程中温度与渗流场和应力场的耦合作用变化规律,引入煤层瓦斯两能态吸附热理论,重新构建煤层温度场控制方程,推导了温度场控制方程中解吸微分热能项的理论求解方法,改进了煤层瓦斯流动的热-流-固多场耦合数学模型;从理论上阐述了煤层瓦斯流动过程中吸附解吸、应力场、温度场、渗流场相互影响的作用机制;利用该模型研究了煤层瓦斯抽采过程中煤层瓦斯流动时的煤层温度、瓦斯压力、煤层渗透率的变化规律;结合已有试验研究结果,对比验证了模型的精确性和合理性;研究结果表明,在煤层瓦斯抽采过程中,煤层温度下降的快、慢受煤层原始瓦斯含量和压力及煤层渗透率的共同影响,煤层渗透率越大,温度下降越快,煤层瓦斯压力和含量越大,温度下降越快;同时,煤层渗透率随抽采时间的增长而增加,越靠近钻孔壁面煤层渗透率增加幅度越大。
In order to study the variation of coupling between temperature and seepage field and stress field in coal seam gas flow, the paper introduced the theory of adsorption heat of coal seam gas two-state and reconstructed the governing equation of temperature field in coal seam. The differential thermal energy desorption Theory solving method is used to improve the thermo-fluid-solid multi-field coupled mathematical model of gas flow in coal seam. The mechanism of the interaction between adsorption and desorption, stress field, temperature field and seepage field in gas flow in coal seam is theoretically expounded. The model was used to study the variation law of coal seam gas temperature, gas pressure and coal seam permeability during gas drainage in coal seam. The accuracy and rationality of the model were verified by comparison with the existing experimental results. The results show that, Coal seam gas drainage process, the coal seam temperature drops quickly and slowly affected by the original coal seam gas content and pressure and permeability of coal seams together, the greater the permeability of the coal seam, the faster the temperature drop, coal seam gas pressure and content of the larger, the temperature dropped The faster the coal seam permeability increases with the increase of pumping time. The closer the coal seam permeability to the borehole wall increases The larger amplitude.