Evaporation of Acoustically Levitated Ouzo Droplets

Ouzo droplet is a multi-component droplet formed by liquids with varying thermophysical properties, volatilities, and miscibility. The evaporation process of ouzo droplets is a spontaneous emulsification process and is a complex multi-physics problem involving fascinating mass and heat transfer phenomena, as well as phase-changing behavior, recently has been drawn significant attention. In this study, evaporation of multi-component droplets composed of ethanol, water, and anise oil is investigated experimentally using acoustic levitation and infrared thermography techniques. The normalized surface area and temperature data are investigated simultaneously to classify the evaporation into five distinct stages. Scaling laws reveal the self-similar evaporation behavior for different size droplets. A numerical model has been deployed to provide additional insights revealing the physics behind the complex evaporation behavior.