Confined liquid distribution in structured packings: Study of liquid films around a perforated topography
Résumé
Falling films on structured packings are extensively studied because of their increased application in the distillation and absorption industries. A class of structured packings consists in stacks of metal sheets. These sheets usually comprise of various complex geometrical intricacies such as corrugations, perforation of various shapes that play a significant role in the local fluid redistribution. The unique flow paths of the liquid and the gas phases over the structured packing, caused by their complex geometry, gives motivation to investigate the physics of the fluid distribution over these topologies. The presence of a topography perturbs the fluid free surface and in a short time, several instabilities can be observed through the deformation of the free surface. The effect of perforations and micro-texture on liquid spreading over the surface of corrugated packing was examined experimentally by Pavlenko et al. (2017). Zhao & Cerro (1992) performed an experimental work over macro and micro structures in which he characterized the mechanics of the viscous film flows by measuring film thickness profiles, streamline patterns and free-surface velocities. More recently, Xie et al. (2018) have studied the liquid flow patterns over several shaped open window at different flow rates. However, in their experiments, perforated plates are supplied with liquid only on one side whereas supply of liquid is maintained on both sides of the metal sheets in real distillation conditions.
In our experimental study, we focus on the fluid redistribution mechanism specific to these topographies in order to clearly understand its contribution towards the spreading of the liquid over a packing. We aim to measure and characterise the local deformation of the film around the topography over a perforated aluminium plate while the fluid supply is maintained on both faces of the plate. The concept of two-face supply of the fluid over such a topographical plate has not been tested before and thus brings new insights on the film behavior around the topographical surfaces.