煤粒瓦斯定压吸附数学模型及数值解算

为了研究瓦斯在煤粒中的流动机理,开展了4组不同初始压力下的煤粒瓦斯定压吸附实验,提取了累计瓦斯吸附量随时间变化的实验数据.基于压力梯度驱动的达西理论和游离瓦斯密度梯度驱动的新扩散模型,建立2种煤粒瓦斯定压吸附数学模型,并利用有限差分法对数学模型进行了数值解算,得到了煤粒内部累计吸附量的模拟数据.将2种模拟结果与实验数据...

Mathematical model and numerical solution of constant pressure adsorption of gas in coal particles

In order to study the flow mechanism of gas in coal particles, four groups of constant pressure adsorption experiments were carried out at different initial pressures, and the experimental data of cumulative gas adsorption volume content with time were extracted. Based on Darcy theory driven by pressure gradient and new diffusion model driven by the density gradient of free gas, two kinds of mathematical models of gas adsorption at constant pressure were established, and the adsorption process was numerically solved by VB program code, and the simulation data of cumulative adsorption volume content inside coal particles were obtained. By comparing and analyzing the two kinds of simulation results with the experimental data, it is found that numerical calculation results are consistent with the experimental data, thus verifying the accuracy of the numerical simulation. In addition, the key proportional coefficients in the two models with the change of pressure are different. The permeability coefficient is negatively correlated with the pressure, and the microchannel diffusion coefficient does not change with the pressure. It is concluded that the diffusion model driven by the density gradient of free gas is more suitable to describe the gas migration law in coal particles than Darcy's law and Fick's law.