Abstract
A method was proposed to determine the ratio of liquid droplet and vapor in the product of ultrasonically-atomized aqueous ethanol solution. A salt which only goes into droplets was used as a tracer. Since no selective partitioning of salts was reported between droplets and bulk solution, the amount of liquid turned into droplets was obtained from the change in the amount of salt. Knowing the ratio of the amount of droplet and vapor provides a clue of understanding the separation mechanism of ethanol enrichment in the fog. The ratio varied with the change in ethanol concentration in feed solution. Ethanol concentration in the fog was measured to discuss the relation between ethanol enrichment and the ratio. A multiphase model was proposed, where the source of the fog was regarded as shell-bearing bubbles and/or droplets. The basic mechanism of the enrichment is regarded as the surface excess of ethanol at the shell. By combining the amount of those droplets and bubbles, predicted values of the ratio were obtained, and were compared with the observed values.
