Coupled Dissolution and Diffusive Interactions of Microbubbles in Irregular Pore Networks
摘要
The dissolution of a dispersed gas phase in a porous medium partially saturated with liquid is a problem of broad practical interest. While capillary equilibration has been shown to affect the evolution of the dispersed phase, its coupling with the underlying diffusive process in the liquid phase remains largely unexplored. Here, we deploy a pore-network model to describe coupled dissolution and diffusive interactions of a lattice of microbubbles in irregular pore networks. We demonstrate that the dissolution process becomes more erratic than in regular networks, because of the complex interplay between local connectivity effects and diffusive shielding between neighboring bubbles. By applying the method of moments, we quantify the evolution of solute mass in the system and compute continuum-scale properties, such as the effective diffusion coefficient of the network and the dissolution rate of the bubble lattice. We observe that the presence of bubbles delays the attainment of an asymptotic diffusive behavior and reduces the spatial extent of the solute plume relative to the same liquid-saturated network. Importantly, collective effects appear to be stronger than effects associated with the local pore connectivity distribution in the network in reducing the rate of dissolution of bubbles. Article Highlights