Heat and Mass Transfer

, Volume 41, Issue 7, pp 667–673 | Cite as

Modeling for heat and mass transfer with phase change in porous wick of CPL evaporator

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A mathematic model is developed to describe heat and mass transfer with phase change in the porous wick of evaporator of capillary pumped loop (CPL). This model with six field variables, including temperature, liquid content, pressure, liquid velocity, vapor velocity and phase-change rate, is closed mathematically with additional pressure relationships introduced. The present model is suitable to the numerical computation, as the established equations become comparatively easy to solve, which is applied to CPL evaporator. The numerical results are obtained and the parameter effects on evaporator are discussed. The study demonstrates that instead of an evaporative interface, there exists an unsaturated two-phase zone between the vapor-saturated zone and the liquid-saturated zone in the wick of CPL evaporator.

Keywords

CPL evaporator Porous wick Phase change Heat and mass transfer Numerical analysis 

Nomenclature

c

Specific heat, J/(KgK)

k

Thermal conductivity, W/(mK)

kv

Equivalent permeability of vapor, m2

kl

Unsaturated permeability of liquid, m2

Kv

Infiltrating conductivity of vapor, ms−1

Kl

Hydraulic conductivity of liquid, ms−1

\(\dot m\)

mass rate of phase change, Kg/(m3s)

P

Pressure, Pa

q

Heat flux, Wm−2

Q

Heat load of the evaporator, W

S

Source term, saturation

t

Time, s

T

Temperature, K(°C)

u

Velocity component in x-direction, ms−1

v

Velocity component in y-direction, ms−1

\(\vec V\)

Velocity vector, ms−1

Greek symbols

γ

Latent heat, JKg−1

ɛ

Phase content, %

μ

Viscosity, Kg/(ms)

υ

Kinematic viscosity, m2s−1

ρ

Density, Kgm−3

ω

Porosity, %

Subscripts

eff

Effective quantities

l

Liquid

s

Solid

v

Vapor

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Notes

Acknowledgements

The current work is financially supported by the National Key Basic Research Development Program of China (No.G2000026303).

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • X. M. Huang
    • 1
  • W. Liu
    • 1
  • A. Nakayama
    • 2
  • S. W. Peng
    • 1
  1. 1.School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhanPeople’s Republic of China
  2. 2.Department of Mechanical EngineeringShizuoka UniversityHamamatsuJapan

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