Absorption of water vapor into the laminar film flow of a lithium bromide-water solution. Influence of variable properties and inlet film thickness on absorption rate.

Abstract

Numerical computations were carried out to determine the mass transfer for the absorption of low pressure water vapor into an aqueous lithium bromide film flowing down a constant temperature vertical flat plate. The film is assumed to be laminar and the velocity profile fully developed. In the current study, the selected operating parameters are expected to be present in the absorbent of an absorption refrigerating machine. The results are summarized as follows : (1) The total absorption mass flow rate over a certain length of the plate takes a maximum value at a certain entrance film thickness. (2) With an increase in the system pressure, entrance concentration and Lewis number, the total absorption mass flow rate is augmented. (3) The total absorption mass flow rate under conditions where variations of the solution properties occur is slightly lower than that of the constant properties.