Pore-scale simulation of flow and mass transfer characteristics of porous particle

The gas permeation effect leads to a significant change of flow and mass transfer characteristics inside a porous particle, which is difficult to be explained by the conventional theory of nonporous particles. In this paper, a combined macroscopic continuous-microscopic discrete model is established for a porous particle. Flow and mass transfer characteristics of a porous particle under steady and transient flow conditions are evaluated. The microscopic pore structure, permeability and transport characteristics of a porous particle are analyzed. The results show that the critical macro-porosity exists between 0.6 and 0.7 under the competition of gas permeation and circumfluence, which influences the dominant mechanism of microscopic and macroscopic forces. Under the transient flow condition, the gas permeation and circumfluence results in the occurrence of double frequency of surface friction drag coefficient and body pressure drag coefficient as well as mass transfer coefficient.