Nomenclature
Q	Heat flux, W∙m−2
h	Convective heat transfer coefficient, W∙m−2∙K−1
T	Temperature, K
v	Velocity, m∙s−1
dm	Hydraulic radius, m
ΔH	Latent heat of water, J∙kg−1
N	Mass flow across membrane, kg∙m−2∙s−1
k	Thermal conductivity, W∙m−1∙K−1
km	Membrane thermal conductivity, W∙m−1∙K−1
kg	Thermal conductivity of air, W∙m−1∙K−1
ks	Thermal conductivity of membrane materials, W∙m−1∙K−1
Dw-a	Diffusivity of water vapor-air mixture, m2∙s−2
Dkn	Knudsen diffusion coefficient, m2∙s−1
P	Vapor pressure, Pa
PT	Total pressure, Pa
R	Gas constant (8.314 J∙mol−1∙K−2)
xs	Molar fraction of solute
mw	Molecular weight of water
b	Height of first grid, m
Sw	Source, kg∙m−3∙s−1
u	Velocity vector, m∙s−1
p	Pressure, Pa
x,y	Cartesian coordinates, m
cp	Specific heat capacity, J∙kg−1∙K−1
D	Mass diffusivity, m2∙s−1
c	concentration, g∙L−1
EE	Evaporation Efficiency, %
CPC	Concentration polarization coefficient, %
t	Time, s
Greek Symbols
δ	Membrane thickness, m
ε	Membrane porosity
λ	Membrane tortuosity
γw	Activity coefficient of water
$\rho$	Density, kg∙m−3
$\sigma$	Viscous stress tensor
$\mu$	Dynamic viscosity, Pa∙s
ϑNa	The equivalent limiting ionic conductance of the sodium
ϑCl	The equivalent limiting ionic conductance of the chloride
Subscripts
f	The bulk of the feed
fm	Membrane surface of the feed
p	The bulk of the permeate
pm	Membrane surface of the permeate
m	Membrane
N	Flux
C	Conduction
Abbreviations
DCMD	Direct contact membrane distillation
FGD	Flue gas desulfurization
MD	Membrane Distillation
CFD	Computational fluid dynamics
CPC	Concentration polarization coefficient
TPC	Temperature polarization coefficient
UDF	User-defined function
EE	Evaporation efficiency