Prediction of bubble shape deformation in aqueous solutions of short-chain alcohols.

The behaviour of bubbles in aqueous solutions of short-chain alcohols depends significantly on the alcohol concentration. At low concentrations, alcohols act as surfactants and slow the rising velocity of the bubble, whereas at higher concentrations, primarily due to the internal arrangement at the molecular level, the desorption of molecules from the bubble surface is facilitated and the mobility of the bubble surface is increased. These factors significantly affect both bubble velocity and deformation. On the basis of experimental data (aqueous solutions of ethanol and propanol in the entire concentration range), two relations were proposed for the estimation of bubble deformation depending on the dimensionless Weber number. The model was successfully verified on an independent data set of the velocity and deformation of bubbles that rise in a stationary liquid. [Display omitted] • Bubble deformation in water-ethanol and water-propanol mixtures was measured. • Bubble deformation can be estimated using the Weber number. • New models were proposed for two alcohol concentration regions. • Results were validated using the experimental bubble velocity data. [ABSTRACT FROM AUTHOR]