Page 273 - gas transport in porous media

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F
F volumetric flow-rate Šolcová and Schneider
n ∗ n matrix with elements {f ij }
K Knudsen coefficient (2/3)(8R g T/πM) 0.5
Kn Knudsen number (λ/2 r )
L column length
L p pellet length
M molecular weight
p
d
N , N , N diffusion molar flux density, permeation molar flux density,
combined molar flux density
N n ∗ 1 vector of combined molar flux densities
P gas pressure in cell compartments
p gas pressure in pores
Pe Peclet number
q t tortuosity of transport-pores
2
r , r integral mean of transport-pore radii, integral mean of squared
transport-pore radii
R pellet radius (equivalent sphere)
R g gas constant
S total cross-section of pellets in cells
t time
t c convection time (L/v)
2
t dif pore-diffusion time (R ε/D TC )
T temperature
U
V , V L volumes of upper- and lower-compartment, resp.
v interstitial carrier gas velocity
x length coordinate in the transport direction
y i mole fraction of component i
α column void fraction
ε, ε t porosity of porous pellet, porosity of transport-pores
η i , η viscosity of component i, mixture viscosity
λ mean free-path length
µ first absolute moment of the impulse response
1 7 7
∞ ∞
c(t) : µ = tc(t)dt/ c(t)dt
1 0 0
ω numerical coefficient
ψ geometric transport parameter (ε t /q t )
Subscripts

A, B, i, j for components

Superscripts

U, L upper and lower cell compartment, resp.