Abstract
The purpose of this paper is to investigate the relation between the acoustic streaming around a acoustically levitated droplet and the rate of mass transfer. External flow structure of a levitated droplet is measured by using PIV technique. We measure a external flow structure around a water and ethanol droplet with several kinds of diameter. Also, we observe the evaporation behavior of the levitated water and ethanol droplet. The droplet diameter decreases with d^2-raw and it is qualitatively in good agreement with the theoretical prediction. It is indicated that flow field around the droplet affects the rate of mass transfer.