Interfacial mass transfer in laminar and turbulent liquid films
Ryan-Bell, Jeremy John
Master of Science
The problem of mass transport across the free surface of both laminar and turbulent liquid films has been studied. The apparatus used in this work consisted of a plate inclined at an angle of 5° to the horizontal. This resulted in a more hydrodynamically smooth interface than normally encountered in other apparatuses used in studies of this kind. A technique was developed whereby representative samples of the liquid film could be obtained at various locations down the inclined plate. The system studied was water-carbon dioxide. In laminar flow it was found that data obtained could be predicted by a molecular diffusion model suggested by Pigford. In the turbulent region, three models are suggested which describe the possible transport mechanisms. Since all three models depend on experimentally determined parameters, it was not possible to determine which mechanism was more likely. However, numerical values of the parameters together with the relevant model should allow a prediction of mass transport for similar gas-liquid systems over the Reynolds number range of 4,500-7,500. The transition from laminar to turbulent flow was found to occur at a Reynolds number of 4,500. No correlation was found between the visual, state of the interface and the transport mechanism involved in the various regimes.