Environmental Engineering Reference
In-Depth Information
KA
KA
2
W
W
W
W
Sp
,
C
C
β≈
Y
+
Y
(2.36)
0
,
∞
p
,
∞
1
+
Sp
,
0
P
3.
When the CO flame remains in contact with the surface of a solid:
KA
KA
+
KA
KA
2
W
W
W
W
Sp
,
S
,
0
C
C
β≈
Y
Y
0
,
∞
p
,
∞
12
+
−
KA
12
+
−
KA
S
,
0
S p
,
0
S
,
0
S p
,
P
(2.37)
The complement number of the material transfer factor
K
for combustion in two-
dimensional stagnation flow is expressed as shown below.
In the cases of (1) and (3):
≈
+
T
T
T
T
π
∞
∞
K
1
−
(2.38)
2
2
s
s
In the case of (2):
≈
−
+
T
T
T
T
4
W
W
π
∞
∞
P
K
1
−
005 1
.
+
Y
(2.39)
0
,
∞
2
2
s
s
0
The symbols used in the expressions above represent the following values:
a
is
velocity gradient, ρ is concentration, µ is coefficient of viscosity. Index
j
refers to
the two-dimensional stagnation flow (
j
= 0) or axisymmetric stagnation flow (
j
= 1).
Y
= mass rate,
W
= molecular weight. Subscripts C, O, and P mean carbon, oxygen,
and carbon dioxide, respectively.
A
S,O
and
A
s,P
are surface Damköhler numbers
defined in the following equation:
T
T
B
T
T
a
(
)
Si
,
∞
A
≡
exp
−
si
,
i
=
0
,
P
(2.40)
Si
,
(
)
j
2
a
µρ
s
S
∞∞
where,
B
S,i
is the frequency factor of surface reaction,
Ta
S,i
is the activation temper-
ature of surface reaction. Subscripts O and P refer to the C-O
2
surface reaction and
C-CO
2
surface reaction, respectively.
The solid carbon test specimen used in this test has the same properties as those
used in past studies.
66,67
The frequency factor of the surface reaction and activation
energy of the specimen are as described below:
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