Response of subcritical evaporation of ethanol/water Bi-component droplet to pressure oscillation

Abstract

A theoretical model for the evaporation of multi-component droplet based on the film theory and the non-ideal vapor–liquid equilibrium is presented and implemented to predict the evaporation of the ethanol/water bi-component droplet under oscillatory pressure. The fugacity model is adopted so that the vapor–liquid equilibrium is determined accurately. Based on the calculation results, response characteristics of the droplet temperature, the evaporation rate of individual component in the droplet and the droplet lifetime have been analyzed. The droplet temperature oscillates in phase with the pressure oscillation. The total evaporation rate as well as the evaporation rate of individual component oscillates with the pressure oscillation at the same frequency but the opposite phase. Moreover, the fractional evaporation rate of more volatile component in the bi-component droplet oscillates under the same phase as the pressure oscillation. The oscillation of environment pressure shortens the lifetime of the droplet.