Flow of liquid films over a single element of structured packing. Comparison of microtextures of various types

Abstract

The paper deals with the theoretical analysis of viscous liquid films flowing down along a single element of a structured packing with large ribs and microtexture in the form of a wavy two-dimensional surface or three-dimensional surface of the “undulating” type. The effect of inertia forces, surface tension, coarse corrugation, and fine texture geometry on the averaged characteristics of the film flow is considered. New equations for calculating a three-dimensional film flow along a plate with double corrugation structure are obtained. In the calculations, the main attention is paid to the effect of various types of microtextures on film spreading. The type, amplitude, angle of fine texture inclination, and Reynolds number of liquid are varied. It is found that the microtexture of three-dimensional “undulating” type has a small effect on liquid film spreading over a single element of the structured packing; the averaged liquid flow rates along and across large ribs depend weakly on the amplitude and inclination angle of fine texture of this type. It is revealed that only the average film thickness is sensitive to a change in the amplitude of microsurface of the “undulating” type. This is very different from the effect that a wavy two-dimensional microtexture has on film spreading along and across the large ribs. In this case, the effect of waviness on spreading hydrodynamics depends substantially on fine texture amplitude and inclination angle.