Geoscience Reference
In-Depth Information
1.0
0.9
0.8
0.7
0.6
0.5
0.4
av
T
/D=1
av
T
/D=5
av
T
/D=20
0.3
0.2
0.1
2
4
6
8
10
DISTANCE FROM PARTICLE CENTER (
r
/
a
)
Fig. 3.2
The concentration profiles of A at different particle sizes a
v
T
=D
D
1; 5; 20.Here
.r/
D
n.r/
n
C
and
D
n
1
n
C
/
outside the limiting sphere (at r
R). Here
˛.a/.n
1
n
C
/
4DR
n
R
D
n.R/
D
n
1
:
(3.78)
The function n.r/ is continuous at r
D
R together with its first derivative.
Excluding n
R
from Eqs.
3.77
and
3.78
yields the profile in the form:
1
b
C
.r/
b
C
.R/
n
r
n
C
n
1
n
C
˛.a/
4DR
D
(3.79)
at r<Rand
n
r
n
C
n
1
n
C
˛.a/
4Dr
D
1
(3.80)
at r
R. Figure
3.2
displays the profile at three different dimensionless particle
sizes.
3.3.6
Discussion
3.3.6.1
Trapping Efficiency
Although Eq.
3.31
is widely used in the aerosol literature, I never met its derivation
for the transition regime. This equation is known to hold in the continuous limit,
