The break-up of thin liquid films due to the intensity of mass transfer in absorption

Abstract

The break-up of thin liquid films during gas absorption has conventionally been attributed to the Marangoni effect. Point-to-point variations in surface tension are thought to arise as a result of the absorption process, the consequent surface convection leading to the break-up of the film into rivulets. In this paper, attention is drawn to a relatively unknown type of instability induced by high intensity interphase mass transfer. This type of instability may occur during the absorption of highly soluble gases and should be considered in conjunction with any associated Marangoni phenomena. In the case of absorption of pure vapours or gases, point-to-point variations in surface tension cannot occur and, under such conditions, film break-up may be the result of instability induced by high interphase flux of solute. Experiments on absorption of acetone into a spherical water film were carried out to support the above hypothesis, and a photographic study demonstrated the behaviour and break-up of the film.