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Numerical Heat Transfer, Part A: Applications
An International Journal of Computation and Methodology
Volume 70, 2016 - Issue 11
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Original Articles

Analyzing slow drying in a porous medium placed adjacent to laminar airflow using a pore-network model

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Pages 1213-1231 | Received 04 Mar 2016, Accepted 13 Jul 2016, Published online: 26 Oct 2016
 

ABSTRACT

A novel unified implicit computational framework and a unique pore-to-cell meshing method is used to predict, by coupling the inside-drying outside-flow processes, the slow drying of a pore-network-represented porous medium placed adjacent to a laminar flow of air in a slit. The effects of numerical algorithms, spatial and temporal discretization schemes, and meshing methods in minimizing computational effort are studied. The numerical solutions of the outer and inner processes are tested against several benchmark studies. The external air velocity affects drying during the initial stages. The microstructure of the pore network (P-N is found to have a strong influence on drying.

Nomenclature

A, Ai, j=

area of throat cross-section or cell faces

C, Csat, C=

liquid vapor concentration/saturated concentration/environment concentration

D, D*=

liquid mass diffusivity

H=

height

l, l*=

throat length

=

mass flux between two pores

M, Md, Mv=

molar mass/molar mass of dry air/molar mass of vapor

MVP=

maximum variation percentage

p, pa, pv, pl=

pressure/atmosphere pressure/vapor pressure/liquid pressure

Pe=

Peclet number

R=

radius of throats

RSN=

random seed number

=

universal gas constant

Re=

Reynolds number

t=

time

T=

temperature

u, Uavg, U*=

velocity/average velocity

x, y=

voordinate

x0=

venter of the spike

γ=

surface tension

δi, j=

distance between two cells or pores

ρg, ρair, ρ*=

gas density/air density

μg,μair, μ*=

gas viscosity/air viscosity

α=

width parameter of the spike

Subscript=
i, j=

index number of cell/pore/throat

Superscript=
n=

time step

Nomenclature

A, Ai, j=

area of throat cross-section or cell faces

C, Csat, C=

liquid vapor concentration/saturated concentration/environment concentration

D, D*=

liquid mass diffusivity

H=

height

l, l*=

throat length

=

mass flux between two pores

M, Md, Mv=

molar mass/molar mass of dry air/molar mass of vapor

MVP=

maximum variation percentage

p, pa, pv, pl=

pressure/atmosphere pressure/vapor pressure/liquid pressure

Pe=

Peclet number

R=

radius of throats

RSN=

random seed number

=

universal gas constant

Re=

Reynolds number

t=

time

T=

temperature

u, Uavg, U*=

velocity/average velocity

x, y=

voordinate

x0=

venter of the spike

γ=

surface tension

δi, j=

distance between two cells or pores

ρg, ρair, ρ*=

gas density/air density

μg,μair, μ*=

gas viscosity/air viscosity

α=

width parameter of the spike

Subscript=
i, j=

index number of cell/pore/throat

Superscript=
n=

time step

Acknowledgments

We would like to thank Dr Marc Prat for providing some insightful guidance during the implementation of our simulation.

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