Skip to main content

Advertisement

SpringerLink
Log in

A numerical study on the absorption of water vapor into a film of aqueous LiBr falling along a vertical plate

  • Original
  • Published:
Heat and Mass Transfer Aims and scope Submit manuscript

Abstract

Absorber is an important component in absorption machines and its characteristics have significant effects on the overall efficiency of absorption machines. This article reports a model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water––cooled vertical plate absorber in the Reynolds number range of 5 < Re < 150. The boundary layer assumptions were used for the transport of mass, momentum and energy equations and the fully implicit finite difference method was employed to solve the governing equations in the film flow. Dependence of lithium bromide aqueous properties to the temperature and concentration and film thickness to vapor absorption was employed. This model can predict temperature, concentration and properties of aqueous profiles as well as the absorption heat and mass fluxes, heat and mass transfer coefficients, Nusslet and Sherwood number of absorber. An analysis for linear distribution of wall temperature condition carries out to investigation the reliability of the present numerical method through comparing with previous investigation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18

Similar content being viewed by others

Abbreviations

D :

Mass diffusivity (m²/s)

g:

Gravitational acceleration (m/s²)

h fg :

Heat of absorption (J/kg)

h m :

Local mass transfer coefficient (m/s)

\( \overline{h}_{\text{m}} \) :

Average mass transfer coefficient (m/s)

h t :

Local heat transfer coefficient (W/m² K)

\( \overline{h}_{\text{t}} \) :

Average heat transfer coefficient (W/m² K)

k :

Thermal conductivity (W/m K)

L :

Plate length (m)

M abs :

Average mass flux (kg/m² s)

m abs :

Absorption mass flux (kg/m² s)

M :

Number of nodes in ε direction

N :

Number of nodes in η direction

Nu :

Nusselt number

P :

Absorber pressure (Pa)

Pr :

Prandtl number = υ/α

q :

Heat flux (W/m²)

Re :

Reynolds number

Sc :

Schmidt number = υ/D

Sh :

Sherwood number

T :

Temperature (°C)

x :

Axis to flow direction (m)

y :

Axis perpendicular to flow direction (m)

u :

Velocity in x direction (m/s)

v :

Velocity in y direction (m/s)

α :

Thermal diffusivity (m²/s)

δ :

Film thickness (m)

ε :

Non-dimensional x axis

Г:

Film flow rate (kg/m.s)

η :

Non-dimensional y axis

μ :

Solution viscosity (kg/m s)

υ :

Kinematic viscosity (m²/s)

ρ :

Solution density (kg/m3)

ω:

Salt (LiBr) mass concentration in the solution

abs:

Absorption

e:

Equilibrium

f:

Film

in:

Inlet

surf:

Surface

s:

Solution

w:

Wall

References

  1. Donate M, Rodriguez L, Lucas AD, Rodrı′guez JF (2006) Thermodynamic evaluation of new absorbent mixtures of lithium bromide and organic salts for absorption refrigeration machines. Int J Refrig 29:30–35

    Article  Google Scholar 

  2. Yoon J, Phan Th T, Moon Ch G, Bansal P (2005) Numerical study on heat and mass transfer characteristic of plate absorber. Appl Therm Eng 25:2219–2235

    Article  Google Scholar 

  3. Nakoryakov VE, Grigoreva NI (1977) Combined heat and mass transfer during absorption in drops and films. J Eng Phys 32(3):243–247

    Article  Google Scholar 

  4. Grossman G (1983) Simultaneous heat and mass transfer in film absorption under laminar flow. Int J Heat Mass Transf 26(3):357–371

    Article  Google Scholar 

  5. Yang R, Wood BD (1992) A numerical modeling of an absorption process on a liquid falling film. Sol Energy 48(3):195–198

    Article  Google Scholar 

  6. Goel N, Yogi Goswami D (2005) A compact falling film absorber. J Heat Transf 127:957–965

    Article  Google Scholar 

  7. Islam Md R, Wijeysundera NE, Ho JC (2003) Performance study of a falling-film absorber with a film-inverting configuration. Int J Refrig 26:909–917

    Article  Google Scholar 

  8. Subramaniam V, Garimella S (2009) From measurements of hydrodynamics to computation of species transport in falling films. Int J Refrig 32:607–626

    Article  Google Scholar 

  9. Medrano M, Bourouis M, Coronas A (2002) Absorption of water vapour in the falling film of water–lithium bromide inside a vertical tube at air-cooling thermal conditions. Int J Therm Sci 41:891–898

    Article  Google Scholar 

  10. Morioka I, Kiyota M (1991) Absorption of water vapor into a wavy film of an aqueos solution of LiBr. JSME Int J Ser II 34(2):183–188

    Google Scholar 

  11. Florides GA, Kalogirou SA, Tassou SA, Wrobel LC (2003) Design and construction of a LiBr–water absorption machine. Energy Convers Manag 44:2483–2508

    Article  Google Scholar 

  12. McNeely LA (1979) Thermodynamic properties of aqueous solutions of lithium bromide. ASHRAE Trans 85:413

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. School of Mechanical Engineering, Sharif University of Technology, 11155-9567, Tehran, Iran

    Shahram Karami & Bijan Farhanieh

Authors
  1. Shahram Karami
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Bijan Farhanieh
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Shahram Karami.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Karami, S., Farhanieh, B. A numerical study on the absorption of water vapor into a film of aqueous LiBr falling along a vertical plate. Heat Mass Transfer 46, 197–207 (2009). https://doi.org/10.1007/s00231-009-0557-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00231-009-0557-y

Keywords

Search

Navigation