Improved characterization of the pore size distribution in full and across scale by a fractal strategy

In this study, the normalized fractal dimension (DN) model of full-scale pore size was established based on the classical fractal scaling relationship of porous materials. The methodology of the established model was described in detail, and the rationality was examined by the classical fractal relationship between the pore volume and specific surface area (SSA). The results indicate that the established model is a continuous function of the fractal dimension and pore size in the full scale, which can more comprehensively symbolize the fractal characteristic of pore size distribution in full scale. In addition, the established model can quantitatively characterize the absolute continuous pore size distribution in full scale, compared with the traditional segmented relatively continuous characterization methods that include the method based on connecting the data on pore volume and SSA, and the method based on the segmented fractal dimensions. The established model can also be employed to quantitatively characterize the pore size distribution across scales. Therefore, the proposed fractal strategy achieves a breakthrough for improving the characterization of the pore size distribution in porous materials, which provides a scientific basis for understanding the fluid transport behavior in porous materials and designing fractal coal-based materials.