Nomenclature:
A	constant parameter
B	constant parameter
C	constant parameter
Cw,in	concentration of water vapor in the inlet air
Cw,out	concentration of water vapor in the outlet air
Cw,t (mol/m3)	concentration of water vapor in tube
Cw (mol/m3)	concentration of water vapor
Cw,s (mol/m3)	concentration of water vapor in shell
Cw,m (mol/m3)	concentration of water vapor in membrane
Ci (mol/m3)	concentration of i species
Cw (mol/m3)	concentration of water vapor
D (m)	diameter of one fiber
Dw,j	diffusion coefficient of water vapor in a substrate
Dw,a (m2/s)	diffusion coefficient of water vapor in air
Dw,m (m2/s)	diffusion coefficient of water vapor in membrane
g (m/s2)	standard acceleration due to gravity
i	denotes the gas species in air
Ji (mol/m2·s)	diffusive flux
k	mass transfer coefficient
K	partition coefficient of water vapor in two phases
km (m/s)	membrane side mass transfer coefficient
ko (m/s)	overall mass transfer coefficient
ks (m/s)	shell side mass transfer coefficient
kt (m/s)	tube side mass transfer coefficient
L (m)	fiber length
n	number of hollow fibers,
P (kPa)	pressure
Pvacuum (kPa)	vacuum pressure
R	radial direction
r1 (µm)	inner radius of the fiber
r2 (µm)	outer radius of the fiber
r3 (µm)	radius of the shell
Re	Reynolds number
RH	relative humidity
Ri	reaction rate of species i
Sc	Schmidt number
Sh	Sherwood number
Sw,air	solubility of water vapor in air
Sw,PDMS	solubility of water vapor in PDMS
T (µm)	thickness of the membrane.
t (s)	time
$\overline{\mathrm{V}}$	average velocity of the fluid inside the tube
V (m/s)	velocity
Vz (m/s)	velocity of air in z direction
Vz,shell (m/s)	velocity of air in the shell in z direction
Vz,tube (m/s)	velocity of air in the tube in z direction
w	water vapor
Z	axial direction
Greeks:
$\mathsf{\rho }$ (kg/m3)	density of air
µ (kg/(m.s))	viscosity of air
$\mathsf{\phi }$	volume fraction