External convective jumping-droplet condensation on a flat plate

摘要

Water vapor condensation is vital to many natural and industrial processes such as building environmental control, power generation, and water desalination. Jumping-droplet condensation of water has recently been shown to have a 10X heat transfer enhancement compared to state-of-the-art filmwise condensation due to the removal of condensate at much smaller length scales (～1 μm) than what is capable with gravitational shedding (～1 mm). However, the efficient removal of jumping droplets can be limited by droplet return to the surface due to gravity, entrainment in bulk convective vapor flow, and entrainment in local condensing vapor flow. If used appropriately, convective condensation has the potential to entrain droplets, hence impeding their return to the surface. In this work, a comprehensive model of external convective jumping-droplet condensation on a superhydrophobic flat plate has been developed for constant heat flux boundary conditions. Boundary layer analysis was used to model the vapor flow over the external plate with condensation modeled as a vapor suction at the wall. The model was used to analyze the effects of jumping droplet size (1