Oscillating nanofluid droplet for micro-cooling

AC electrowetting is used to induce oscillation in a nanofluid droplet with significant changes in the shape dependent parameters at an optimized frequency. The presence of the synthesized silver nanoparticles not only enhances the wetting characteristics of the resulting nanofluid droplets, but leads to the augmentation of their heat extraction capability from a hot spot. The low frequency AC electrowetting induced droplet shape deformation generates surface waves and associated internal flow inside the droplet. This augments the convective heat transfer process resulting in additional evaporative cooling. The imposed internal flow and mixing also contribute to the reuse of the residual (after evaporation) nanoparticles to recreate the nanofluid droplet on the substrate. The generated surface waves are characterized using image analysis of the oscillating droplets in terms of their amplitude, frequency and damping. A model based on Stoke's drift phenomenon is used to analyze the results indicating augmented heat transfer in the low frequency regime.