Levitation of evaporating microscale droplets over solid surfaces

We develop an analytical model to describe recent experimental observations of levitation of evaporating microscale droplets over heated solid surfaces for temperatures far below the Leidenfrost point. Flow patterns around the droplet are determined. Formulas for levitation force are obtained and used to determine the levitation height as a function of drop radius. The results are compared to the predictions of models representing the droplets as point sources in the hydrodynamic equations and with the experimental data. Our model predictions are in good agreement with the experiments except for very small droplets which tend to levitate at higher than expected height.