Bubble rising dynamics with obstacles and dendrite in viscous electrolytes: A smoothed boundary method reformulated phase-field lattice-Boltzmann study

Numerical simulation of bubble–obstacle interactions is a critical issue in electrochemical systems, multiphase flows, and microfluidics, with its complexity stemming from the coupling of hydrodynamic behavior with multiple factors such as interfacial tension, contact angle, boundary conditions, and geometric configurations. In this paper, the bubble rising dynamics in viscous electrolytes with obstacles and dendrite was investigated by using a reformulated phase-field lattice-Boltzmann method integrated with the smoothed boundary method. A novel methodology that integrates image processing techniques with interface tracking techniques to generate diffuse interfaces for arbitrary structures in the computational domain was proposed for phase-field simulations. The dependence of a single rising bubble on the domain size was first investigated to reasonably reduce the wall effect that can strongly affect the flow field, and the effect of the Eötvös number on the morphological evolution of the rising bubble was discussed. Cylindrical, vertical, unilateral horizontal, and unilateral horizontal obstacles and stationary dendritic structures with various wettability properties are introduced to investigate the bubble rising dynamics. It can be found that dewetting surfaces limit the bubble–obstacle contact, enabling low-deformation sliding, whereas wetting surfaces amplify adhesion forces, expanding contact area and triggering shear-driven necking instabilities. Furthermore, the interaction of multiple rising bubbles with the stationary dendrite was numerically investigated, and a synergistic wake effect that accelerates the trailing bubbles results in lateral trajectory deviations.