The influence of small surface waves on mass transfer from pure gases into water has been investigated. Small amplitude progressive two-dimensional waves were mechanically generated a t the liquid surface for the wave studies. Control experiments with nonwaved surfaces were also conducted. An effective diffusivity was used to correlate the data. Marked increases in mass transfer over that predicted by molecular diffusion for the no-wave control runs are attributed to natural convection motions, and are probably caused by density and surface tension variations.
Waves or ripples frequently occur a t fluid-fluid interfaces (4, 15) and their fluid mechanical behavior has been widely studied (19). However, very few quantitative investigations have been made of the effect of waves on interfacial mass transfer. The objective of this study was to provide such information for small progressive twodimensional waves with pure gas absorption into water.
This investigation deals with contact times of an hour or more. Practical application for times of this length lie mainly in the environmental area. However, methods and techniques developed may be applied to shorter contact rimes.
An unexpected result was encountered for the no-wave control runs. Mass transfer could not be explained simply in terms of the usual buoyant forces. It appears that even for the slightly soluble gases studied some degree of surface motion arises from Marangoni instability ( 1 7).