Impact of a Developing Velocity Profile on Heat and Mass Transfer in Absorbing Laminar Falling Films1. Issue 1 (22nd December 2015)

• Record Type: Journal Article
• Authors: Mittermaier, Martin; Ziegler, Felix
• Is Part Of: Chemie Ingenieur Technik. Volume 88:Issue 1/2(2016)
• Page Start: 139
• Page End: 146
• Publication Date: 2015-12-22
• Subjects: Absorption -- Boundary layer approximation -- Entrance region -- Film flow -- Uni‐directional diffusion; Chemical engineering -- Patents -- Periodicals; Chemical engineering -- Periodicals; Chemical industry -- Periodicals; Chemistry, Technical -- Periodicals; 660.05
• DOI: 10.1002/cite.201500093
• Languages: English
• ISSNs: 0009-286X

Abstract

Abstract: This study describes a developing laminar falling film over a vertical plate while heat and mass transfer occurs. The model accounts for a developing film thickness and uni‐directional diffusion. The fluid properties are assumed to be constant, and latent heat, which is relatively large in comparison to the sensible heat, is set free at the liquid‐vapor interface. Temperature and concentration profiles in the film, the development of the interface velocity, as well as the absorbed mass fluxes are presented and two different boundary conditions have been applied to the inlet of the film. Abstract : Starting with a homogenous velocity higher than the mean one of a fully developed profile leads to an earlier onset of absorption and results in a 10 % higher accumulated absorbed mass flux. When the mass diffusivity is reduced by a factor of 10 – which is relevant for absorbents such as ionic liquids – the effect is more pronounced.