热力耦合作用下煤样瓦斯渗透特性数值模拟

针对含瓦斯煤渗透率在热力耦合作用下的演变规律,利用多物理场耦合控制方程建立相应的数值模型,对实验工况进行数值求解.将实验及数值模拟结果进行对比分析得出如下结论:1综合不同瓦斯压力情况下的轴压、围压对渗透率影响,模拟结果中渗透率普遍高于实验数据;2模拟计算得到的围压与渗透率之间呈指数关系,与实验结果的吻合度较高;3利用COMSOL Multiphysics数值模拟研究热力耦合情况下含瓦斯煤渗透率的影响规律,轴压处于高应力场下的模拟吻合度高于低应力场,采用单孔瓦斯渗流模型对高应力场的计算吻合度更好。

Numerical Nimulation of Gas Permeability Characteristics of Coal Samples under Thermal Mechanical Coupling

For the permeabilityevolvement rule about coal samples containing gas, numerical solution was carried out about experimental operating conditions, that corresponding numerical model was established using more physical field coupling control equation. The following conclusions were got based on the comparison and analysis of experiment and numerical simulation results: (1) coal sample permeability presents downtrend with the rise of temperature, the change curve was "S" type, and the function expression of the curve was given. (2)coal sample permeability could be divided into 5 stages with temperature variation curve, respectively for the slow decline phase, the acceleration of the decline stage, the deceleration phase, the two accelerated decline stage, the slow stage. (3)affected by temperature changes, volumetric strain of coal sample under load has an increasing trend, change process curve could be divided into rise-slow-rise again-then slow down four stages, it also correspond to permeability change with temperature process.