The effect of axial acoustic fields on the evaporation of individual drople
ts is investigated bath experimentally and theoretically. A setup was devel
oped in which images of droplets moving through an acoustic field were acqu
ired using a state-of-the-art, high-speed, intensified video system. The ev
aporation rates of droplets were determined from the droplet diameters meas
ured from these images. Experimental investigations using methanol droplets
showed that the presence of an acoustic field significantly enhances the e
vaporation of droplets. The evaporation rate is a strong function of the ac
oustic amplitude, but increases only slightly with frequency, The effect of
acoustic oscillations on water and methanol droplet evaporation was theore
tically modeled by numerically integrating the differential equations for d
roplet mass, momentum, and heat transfer. The model uses quasisteady correl
ations for momentum heat and mass transfer. The model predicted the measure
d trends correctly However, the quantitative agreement of these predictions
with the experimental data depends strongly on the correlations for Nussul
t and Sherwood numbers used to model the energy and mass transfer, respecti
vely.