Thin film flow over structured packings at moderate Reynolds numbers

A model describing the dynamic evolution of waves on laminar falling wavy films at low to moderate Reynolds numbers (Re < 30) over corrugated surfaces is presented. This model is based on the integral balance method, which is used to simplify the analysis by assuming a parabolic velocity profile within the bulk of the film. The predictions of this model are compared to those obtained from a computational fluid dynamics (CFD) code for which no assumptions regarding the film velocity profile are made. The film evolution profiles, obtained via numerical solution of the model equations, are used to calculate the ratio of film interfacial area to that of the substrate. The model predicts suppression of wave growth on a corrugated surface. The model is also used to predict the effect of packing geometry on the flow characteristics, which may improve packing design. Solutions obtained for Re similar to 200 using the CFD code demonstrate the degree of fluid accumulation within the 'valleys' of the structured substrate wherein re-circulation occurs. (c) 2005 Elsevier Ltd. All rights reserved.