Convective evaporation model of sessile droplets in a turbulent flow - comparison with wind tunnel data

摘要

A semi-analytic model for convective evaporation of sessile droplets from solid surface has been developed. The effect of turbulence on evaporation is incorporated into the model through the use of the friction velocity. The friction velocity is calculated from the wall shear stress that was obtained experimentally as a function of free stream velocity and turbulence intensity. In the model, the Reynolds number based on the friction velocity was used because it is more pertinent for sessile droplets than the Reynolds number based on the free stream velocity. Thus formulated model has been successfully validated with wind tunnel data, where a very good agreement between the model predictions and experimental measurements is observed. By utilizing the model, a unique evaporation master curve that correlates the normalized evaporation mass and the non-dimensional time corrected for the influence of the driving force was developed for all droplet sizes, free stream velocities, turbulence intensities, and the surrounding temperatures.