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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

MODELING THE COUPLED HEAT AND MASS TRANSFER IN A FALLING FILM: application to absorbers and desorbers in absorption heat pumps

Get access (open in a dialog) DOI: 10.1615/IHTC8.1730
pages 1971-1976

Abstract

In a falling film used for the absorption of a vapor in a liquid or for the desorption of a volatile component from a solution, the simultaneous heat and mass transfers are coupled. Six different models are proposed, both for the laminar and the non-laminar flow regimes.

In this latter case, the turbulence is modelised, either with a cascade of alternate perfect mixers and laminar exchangers, or with an analytic expression of the turbulent diffusivities as a power function of the distance from the interface.

The evolution of each liquid particle in the falling film is shown by a trajectory on a new diagram where the local temperature is plotted as a function of the local concentration of the volatile component. Various particles at the same level are linked by "tie lines", and the mean trajectory for the bulk of the liquid is the "operating line".