Modeling of an oscillating liquid bridge and its energy harvesting: Simulation and Experiment*

In order to carry out parametric studies on the Reverse-Electro-Wetting on Dielectric (REWOD) phenomenon, which has been attracting attention as a part of energy harvesting technology in recent years, basic research on the physical behavior analysis of vibrating liquid-bridge is essential. In this study, a liquid droplet oscillating between two plates is visualized and the voltage output value was measured by REWOD. For the upper plate, hydrophobic surface treated by PTFE is used and the lower plate is tested using its hydrophilic surface properties of ITO glass. A modeling study was carried out on the dynamic behavior of vibrating liquid-bridge between two flat plates using the phase field method based on the finite element method. For incompressible fluids, the Navier-Stokes equation including gravity force and surface tension force is employed. In comparison with the contact area measured in the experiment, the analytical results agree with each other within 10% error range. Furthermore, experimental and analytical studies are carried out on the REWOD characteristics of the mixture of glycerol and pure water at different concentrations.