The swelling deformations of coal structures during the methane adsorption cause the changes of the gas migration channels such as mesopores and fractures, which poses a great challenge to evaluate the methane migration efficiency in pore-fracture network structures of coal. Because of the complexity of the multi-scale inhomogeneity meso-structure in coal, the previous studies were failed to propose a unified equation to accurately describe and predict the complex deformation of coal structures during methane adsorption. Through lots of researches of meso structures deformation during methane adsorption in coal, the local area density homogenization effect of the meso structures in coal during methane adsorption was discovered. In view of this, the mechanism of the local area density homogenization effect was analyzed by establish a new model of coal structure, and the local area density homogenization equation of methane adsorption in coal was derived. It indicated that the deformation of meso target structure in coal during the methane adsorption is mainly determined by the density ratio of the target structure to the local area, and the swelling deformation of the local area that contains the target structure, as well as the density homogenization coefficient. Through multi-scale three-dimensional segmentation and statistics of the Computed Tomography (CT) scan data of anthracite sample adsorbed methane under different adsorption pressures, the rule of the local area density homogenization effect was verified. It was found that the deformations of the meso structures in coal during the methane adsorption was capable to fit to the local area density homogenization equation of methane adsorption in coal under different adsorption pressures and observation scales. The calculation accuracy of this equation was determined by the analysis of the 95% confidence intervals of the density homogenization coefficient η. The local area density homogenization equation provides a way to describe and predict deformation behavers of coal structures based on the their density information obtained by CT scanning, and has great significance for the numerical simulation of methane dynamic seepage characteristics in multi-scale structures of coal in the CBM exploitation process.

煤在甲烷吸附过程中的溶胀变形引起气体运移通道的变化，如介孔和裂缝，这对评价煤的孔隙-裂缝网络结构中的甲烷运移效率提出了很大的挑战。由于煤中多尺度非均质细观结构的复杂性，以前的研究未能提出一个统一的方程来准确描述和预测甲烷吸附过程中煤结构的复杂变形。通过对煤中甲烷吸附过程中细观结构变形的大量研究，发现了煤中甲烷吸附过程中细观结构的局部密度均匀化作用。鉴于此，建立了煤结构新模型，分析了局部密度均质作用的机理，推导了煤中甲烷吸附的局部密度均质方程。结果表明，煤中甲烷目标结构在甲烷吸附过程中的变形主要取决于目标结构与局部区域的密度比，包含目标结构的局部区域的膨胀变形以及密度。均质系数。通过多尺度三维分割和无烟煤样品在不同吸附压力下吸附甲烷的计算机断层扫描（CT）扫描数据的统计，验证了局部密度均匀作用的规律。研究发现，在不同的吸附压力和观测尺度下，煤中甲烷吸附过程中细观结构的变形能够拟合煤中甲烷吸附的局部密度均化方程。通过分析密度均化系数的95％置信区间可以确定该方程的计算精度η。局部密度均匀化方程提供了一种基于CT扫描获得的密度结构信息来描述和预测煤结构变形行为的方法，对于煤多尺度结构中甲烷动态渗流特征的数值模拟具有重要意义。煤层气开采过程。