Absorption of Water Vapor into Lithium Bromide-water Solution Film Falling along a Vertical Plate

Mathematical model of absorption on a horizontal film of lithium bromide water solution flowing on a cooled wall under the action of shear stress is numerically investigated in this paper. The shear stress on the film surface is set by the motion of co-current or counter-current surrounding saturated water vapor flow. It is known that the external shear stress is caused by the motion of surrounding saturated water vapor intensificate the process of non-isothermal absorption in comparison with the fixed-vapor regime. Our calculations have shown that at low values of heat flux the film temperature and vapor concentration in the solution downstream increases due to absorption.

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Modeling of conjugated heat and mass transfer in the entrance region of falling liquid film at various values of the Froude number

MATEC Web of Conferences ◽

10.1051/matecconf/201819401007 ◽

2018 ◽

Vol 194 ◽

pp. 01007

Author(s):

Maria V. Bartashevich

Keyword(s):

Heat Transfer ◽

Mass Transfer ◽

Liquid Film ◽

Froude Number ◽

Heat And Mass Transfer ◽

Water Solution ◽

Lithium Bromide ◽

Entrance Region ◽

Falling Film ◽

Falling Liquid Film

Mathematical model of conjugated heat and mass transfer in absorption on the entrance region of the semi-infinite liquid film of lithium bromide water solution is investigated for different values of Froude number. The calculations shown that larger values of Froude number corresponds to a smaller thickness of the falling film. It was demonstrated that for large values of the Froude number the heat transfer from the surface is greater than for smaller values.

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Exergy calculation of lithium bromide-water solution and its application in the exergetic evaluation of absorption refrigeration systems LiBr-H2O

International Journal of Energy Research ◽

10.1002/er.1790 ◽

2010 ◽

Vol 36 (2) ◽

pp. 166-181 ◽

Cited By ~ 61

Author(s):

Reynaldo Palacios-Bereche ◽

R. Gonzales ◽

S. A. Nebra

Keyword(s):

Water Solution ◽

Lithium Bromide ◽

Absorption Refrigeration

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Effects of a Nonabsorbable Gas on Interfacial Heat and Mass Transfer for the Entrance Region of a Falling Film Absorber

Journal of Solar Energy Engineering ◽

10.1115/1.2847928 ◽

1996 ◽

Vol 118 (1) ◽

pp. 45-49 ◽

Cited By ~ 10

Author(s):

T. A. Ameel ◽

H. M. Habib ◽

B. D. Wood

Keyword(s):

Mass Transfer ◽

Water Vapor ◽

Analytical Solution ◽

Liquid Film ◽

Heat And Mass Transfer ◽

Vertical Wall ◽

Lithium Bromide ◽

Entrance Region ◽

Falling Film ◽

Aqueous Lithium Bromide

An analytical solution is presented for the effect of air (nonabsorbable gas) on the heat and mass transfer rates during the absorption of water vapor (absorbate) by a falling laminar film of aqueous lithium bromide (absorbent), an important process in a proposed open-cycle solar absorption cooling system. The analysis was restricted to the entrance region where an analytical solution is possible. The model consists of a falling film of aqueous lithium bromide flowing down a vertical wall which is kept at uniform temperature. The liquid film is in contact with a gas consisting of a mixture of water vapor and air. The gas phase is moving under the influence of the drag from the falling liquid film. The governing equations are written with a set of interfacial and boundary conditions and solved analytically for the two phases. Heat and mass transfer results are presented for a range of uniform inlet air concentrations. It was found that the concentration of the nonabsorbable gas increases sharply at the liquid gas interface. The absorption of the absorbate in the entrance region showed a continuous reduction with an increase in the amount of air.

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