Shear driven droplet jumping dynamics induced by Electrowetting

Droplet formation, condensation, and transport are ubiquitous in various industries involving energy conversion and power generation to enhance heat transfer. Air-water transport through the gas diffusion layers of electrochemical reactors is crucial for its cell performance. Recently, Sur et al. (2018) presented electrowetting (EW) as a new tool to enhance pool boiling heat transfer. In such applications, the interplay between the incoming air and ejecting droplet is pivotal in determining the overall performance. This study investigates the transport dynamics of EW induced droplet ejection in shear flow. A high-density ratio based lattice Boltzmann method is employed to model the ejection dynamics and a geometry based contact angle formulation is used to capture the three-phase contact line. We observe a characteristic head vortex at the leading end of the droplet, the strength of which increases with an increase in shear rate. The droplet trajectory, deformation parameter, and surface energy are found to increase with an increase in the applied voltage. Variations in pulse width induce a phase shift in the temporal evolution of trajectory and deformation parameter. Due to an increase in drag forces, the droplet traverses larger streamwise distance at higher gas densities.