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KSME Journal

, Volume 9, Issue 1, pp 115–122 | Cite as

Absorption of water vapor into wavy-laminar falling film of aqueous lithium-bromide

  • Byong Joo Kim
  • In Seak Kang
Article

Abstract

Absorption processes of water vapor into lithium bromide-water solution film inside a vertical tube were studied experimentally. The heat and mass transfer coefficients were measured as a function of film Reynolds number in the range of 30–200. The variables considered were system pressure, coolant and solution temperatures whose differences were kept constant. Optimum film Reynolds number was found to exist for a maximun heat and mass transfer.

Key Words

Absorption Process LiBr-Water Solution Wavy-Laminar Falling Film Heat and Mass Transfer 

Nomenclature

A

Heat transfer area (m2)

Cp

Specific heat at constant pressure (J/kgK)

C

Mass concentration of LiBr in solution (%)

D

Mass diffusion coefficients (m2/s)

g

Gravitational acceleration (m/s2)

Ga

Galileo number=(z/L)3

h

Convective heat transfer coefficient (W/m2K)

k

Thermal conductivity (W/mK)

L

Characteristic length (m)=(μ 2/ρ 2g)1/3

m

Mass flowrate (kg/s)

Nu

Nusselt number=hL/k

Q

Heat transfer rate (W)

q

Heat flux (W/m2)

Re

Film Reynolds Number=4Γ/μ

Sc

Schmidt number=ν/D

Sh

Sherwood number=βL/D

T

Temperature (K)

ΔT

Temperature difference (K)

U

Overall heat transfer coefficient (W/m2K)

z

Absorber length (m)

β

Average mass transfer coefficient (m/s)

Γ

Mass flux (kg/ms)

δ

Film thickness (m)=(3μΓ/ρ 2 g)1/2

μ

Viscosity (Pa s)

ν

Kinematic viscosity (m2/s)

ϱ

Density (kg/m3)

σ

Surface tension (N/m)

ζ

Mass concentration of water in solution (kg/m3)

Subscript

a

Absorption

c

Coolant

i

Interface

in

Incoming

lm

Logarithmic mean

out

Outgoing

s

LiBr-Water solution

w

Absorber tube wall

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References

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Copyright information

© The Korean Society of Mechanical Engineers (KSME) 1995

Authors and Affiliations

  • Byong Joo Kim
    • 1
  • In Seak Kang
    • 2
  1. 1.Department of Mechanical EngineeringHongik UniversitySeoulKorea
  2. 2.Living System LaboratoryGold Star Co.SeoulKorea

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