FRACTAL ANALYSIS OF SURFACE DIFFUSION EFFECTS ON GAS PERMEABILITY OF FRACTAL POROUS MEDIA IN THE SLIP FLOW REGIME

In the study of gas transport in micro- and nano-porous media, accurate characterization of the slip effect is crucial, as it directly impacts the precision and validity of gas permeability predictions. In the slip flow regime, the interactions between gas molecules and the surfaces of porous media become significant. However, current research often neglects the influence of surface diffusion on gas permeability, particularly employing fractal theory for modeling, where the consideration of surface diffusion factors remains limited. This study constructs the gas permeability prediction model for the slip flow regime in capillary bundle porous media based on fractal geometry theory, incorporating a nonlinear weighting factor to characterize the synergistic effects of surface diffusion, viscous flow, and Knudsen diffusion. Experimental validation demonstrates a strong agreement between the model predictions and experimental data. Furthermore, the mechanisms of how the structural parameters influence gas permeability in fractal porous media are revealed. This research provides a new theoretical framework for gas transport in complex porous media.