Numerical Simulation of Jumping Droplet Condensation

Jumping droplet condensation has been shown to enhance heat transfer performance (approximate to 100%) when compared to dropwise condensation by reducing the time-averaged droplet size (approximate to 10 mu m) on the condensing surface. Here, we develop a rigorous, three-dimensional numerical simulation of jumping droplet condensation to compute the steady-state time-averaged droplet size distribution. To characterize the criteria for achieving steady state, we use maximum radii (R-max) tracking on the surface, showing that R-max settles to an average in time once steady state is reached. The effects of the minimum jumping radius (0.1-10 mu m), maximum jumping radius, apparent advancing contact angle (150-175 degrees), and droplet growth rate were investigated. We provide a numerical fit for the droplet size distribution with an overall correlation coefficient greater than 0.995. The heat transfer performance was evaluated as a function of apparent contact angle and hydrophobic coating thickness, showing excellent agreement with prior experimentally measured values. Our simulations uncovered that droplet size mismatch during coalescence has the potential to impede the achievement of steady state and describe a new flooding mechanism for jumping droplet condensation. Our work not only develops a unified numerical model for jumping droplet condensation that is extendable to a plethora of other conditions but also demonstrates design criteria for nonwetting surface manufacture for enhanced jumping droplet condensation heat transfer.