Liquid flow over textured surfaces. 1. Contact angles

This research was directed toward a better understanding of the mass-transf er processes that occur in distillation columns containing structured packi ngs. These packings are designed to create an-extensive gas-liquid interfac ial area, through a combination of packing surface texturing and geometrica l arrangement in the column. Thus, the spreading tendencies of a liquid flo wing over these special surfaces represent an important factor in the choic e of packing for a given separation system. Part 1 of this series of papers deals with basic relationships between the liquid and the solid surface, a s indicated by the contact angle. Various liquid-solid combinations were te sted for contact angle using the Wilhemy plate technique, which was found t o be applicable for flat or corrugated textured surfaces. Several variables thought to affect the contact angle were studied: surface tension and visc osity of the liquid, type of metal, type of texturing, and shape of the sur face. Part 2 of the series will show how contact angle can be combined with liquid flow rate and packing geometry for predicting the mass-transfer per formance of a particular structured packing application.