MASS TRANSFER INVESTIGATIONS DURING DROPLET FORMATION BY MEANS OF A MODIFIED LIQUID SCINTILLATION TECHNIQUE

Abstract

Single droplets were formed at the tip of different capillaries employing high droplet formation rates and continuous phase flow rates. The mass transfer of acetic and / or propionic acid from toluene droplets and acetone from n-butyl acetate droplets into the continuous water phase was measured during droplet formation with a time resolution of 10 msec by a modified liquid scintillation technique. The solute concentration, as a function of time, passes an inflexion point during the first 0.5 sees. By employing the mass balance and the developing droplet geometry the instantaneous mass transfer coefficient was determined, which passes a maximum at the inflexion point of the concentration vs. time curve. The influence of the location of the partition coefficient, the droplet Reynolds number and the continuous phase Reynolds number on the instantaneous mass transfer coefficient was investigated. Serious deficiencies of published models are discussed.