Numerical simulation on vapor absorption by wavy lithium bromide aqueous solution films

Abstract

Numerical simulation has been made on heat and mass transfer of vapor absorption by wavy lithium bromide aqueous solution films. The velocity fields and interface positions are obtained by VOF model. Solitary waves are generated by periodically disturbed inflow boundary. Based on these, the temperature and concentration fields are obtained with a stationary interface shape. The effect of solitary waves on the heat and mass transfer across the film is investigated. It is shown that due to the mixing of circulation and stretch of large film thickness, the gradient of concentration and absorption rate decrease for solitary wave region. The region of capillary waves shows a significant amount of absorption enhancement. The percentage of absorption for the different regions is quantified.

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Abbreviations

C :

Concentration of H2O (% by weight)

c P :

Specific heat (J/kg K)

D AB :

Diffusion coefficient (m2/s)

f :

Disturbance frequency (Hz)

\( \vec{F} \) :

Source term

g :

Gravitational acceleration (m/s2)

h :

Heat transfer coefficient (W/m2 K)

H a :

Absorption heat (kJ/kg)

h m :

Mass transfer coefficient (m/s)

m x :

Absorption rate (kg/m2 s)

M x :

Total absorption rate (kg/s)

q :

Heat flux at the interface

Re :

Reynolds number 4Γ/μ

t :

Time(s)

T :

Temperature (°C)

u :

Streamwise velocity (m/s)

U w :

Wave celerity (m/s)

v :

Transverse velocity (m/s)

We :

Webber number \( We = \rho u_{0}^{2} \delta_{0} /\sigma \)

x :

Streamwise coordinate (m)

y :

Transverse coordinate (m)

δ :

Film thickness (mm)

ρ :

Density (kg/m3)

μ :

Viscosity (Pa s)

σ :

Surface tension (N/m)

α :

Thermal diffusivity (m2/s)

α q :

Volume fraction

ε :

Disturbance amplitude

λ :

Thermal conductivity (W/m K)

0:

Nusselt solution

L:

Liquid

G:

Gas

i:

Interface

w:

Wall

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Acknowledgments

The authors are grateful for financial support by The National High Technology Research and Development Program of China (863 Program, 2007AA05Z214), National Natural Science Foundation of China (50476072) and the fund of New Century Excellent Talents in Universities of State Ministry Education of China (NCET-05-0280).

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Correspondence to Xuehu Ma.

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Bo, S., Ma, X., Chen, H. et al. Numerical simulation on vapor absorption by wavy lithium bromide aqueous solution films. Heat Mass Transfer 47, 1611 (2011). https://doi.org/10.1007/s00231-011-0820-x

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Keywords

  • Solitary Wave
  • Mass Transfer Coefficient
  • Capillary Wave
  • High Concentration Solution
  • Lithium Bromide