An analytical/numerical evaporation model for an oscillating spheroidal droplet in a potential flow

Abstract

An analytical/numerical model for the evaporation of an oscillating droplet is proposed, by solving the species conservation equation in the gas phase in a generalized spheroidal coordinate system. The quasi-steady assumption is released, and the effect of the moving interface on the droplet evaporation is discussed. The evaporation characteristic of an oscillating droplet differs from that under quasi-steady conditions. The differences in evaporation flux vary $-12.5\text{\%}\sim 12.7\text{\%}$ at the poles, and $-6.0\text{\%}\sim 6.6\text{\%}$ at the equator for an initial aspect ratio of 1.2. This difference leads to the evaporation rate and oscillation being out of phase, although having the same frequency. The amplitude of the evaporation rate depends on the initial droplet deformation, whether the droplet shape is prolate or oblate. The mass loss of the droplet within one period rises, as the initial droplet deformation increases. Different evaporating conditions have a slight effect on the evaporation characteristic.