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Falling film absorption on a cylindrical tube
Author(s) -
Conlisk A. T.
Publication year - 1992
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690381105
Subject(s) - mass transfer , mechanics , work (physics) , thermodynamics , absorption (acoustics) , tube (container) , absorption heat pump , chemistry , mass fraction , lithium bromide , laplace transform , materials science , heat pump , composite material , mathematics , physics , mathematical analysis , heat exchanger
The falling liquid film has become a popular means of transferring heat and mass from a vapor to a binary liquid film; applications include heat pump systems, desalination, and gas‐liquid contactors. In the heat pump application, in particular, the length of the liquid film is a crucial factor because of size and weight limitations. Consequently, it is desirable to be able to predict the amount of mass absorbed in a given length of tube. In this work the absorption of water vapor into a Lithium‐Bromide Water mixture is considered. It is shown that mass transfer takes place in a thin layer of fluid near the liquid‐vapor interface which is indicative of a very high level of liquid‐side mass‐transfer resistance. Closed form solutions for the velocity field may be used to derive a simple closed form solution for the mass fraction. For very thin films the temperature distribution may be obtained analytically in Laplace transform space; however, due to the complexity of the solution, numerical techniques are employed to obtain quantitative results. For thicker films a closed form solution for the temperature may be obtained as well. The principal objective of this work is to develop a design procedure not requiring a significant amount of numerical work whereby the absorption capacity of a given tube may be predicted as a function of the governing geometrical and physical parameters. The analytical/numerical results are presented for parameters corresponding to those of recent experiments and the agreement between theory and experiment is good.