Blocking phenomenon induced by droplet electrocoalescence and wavy walls

Abstract

This study explores the impact of wavy walls and electric fields on the deformation and coalescence of droplets using a fully coupled model developed in COMSOL. The model integrates the Navier–Stokes equations, Maxwell stress tensor, and phase-field model to analyze the effects of electric field strength, wavy wall amplitude, and wavy wall wavelength. It can be found that in a cavity with flat walls and no applied electric field, droplets coalesce and descend. At low electric field strengths, droplets adhere to one sidewall, altering their descent. With an increased potential of 2000 V, droplets coalesce to form a stationary barrier layer that divides the cavity into upper and lower sections. The presence of wavy walls significantly influences droplet behavior. At A = 0.5, L = 5, and V0 = 2000 V, an inclined barrier layer form. Increasing the A enhances the influence of the wavy walls, thereby decelerating the descent of the droplets. Conversely, reduced L inhibits droplet descent. This study highlights the complex interplay between electric fields and wavy walls in controlling droplet dynamics.