Geoscience Reference
In-Depth Information
0.6
0.5
0.4
0.3
0.2
0.1
6
DISTANCE FROM THE PARTICLE CENTER
8
10
Fig. 3.6
Concentration profile versus distance from the particle center.
Solid curve
shows results
from the numerical solution of the Boltzmann equation (Williams and Loyalka
1991
; Loyalka et al.
1989
). The
second curve
is the analytical result (Eqs.
3.79
and
3.80
)
or
a
D
2
S
p
2
C
S
p
q
1
C
a
v
T
1
;
(3.93)
2D
2
where
D
n
1
n
C
.
3.4
Evaporation
The evaporation process demands some more attention, because now we must
consider the motion of the evaporating molecule inside the particle, then crossing the
interface and then the diffusion in the gas phase. The latter stage can be considered
