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Chapter 12
Radiation Heat Transfer
1272
The temperature, pressure, and composition of combustion gases flowing inside long tubes are
given. The rate of heat transfer from combustion gases to tube wall is to be determined.
Assumptions
All the gases in the mixture are ideal gases.
Analysis
The mean beam length for an infinite cicrcular
cylinder is, from Table 124,
L
= 0.95(0.10 m) = 0.095 m
Then,
atm
ft
0.056
atm
m
0171
.
0
m)
atm)(0.095
18
.
0
(
atm
ft
.037
0
atm
m
0114
.
0
m)
atm)(0.095
12
.
0
(
⋅
=
⋅
=
=
⋅
=
⋅
=
=
L
P
L
P
w
c
The emissivities of CO
2
and H
2
O corresponding to these values at
the gas temperature of
T
g
= 800 K and 1atm are, from Fig. 1236,
T
s
=
500 K
D
= 10 cm
Combustion
gases, 1 atm
T
g
=
800 K
055
.
0
atm
1
,
=
ε
c
and
050
.
0
atm
1
,
=
ε
w
Both CO
2
and H
2
O are present in the same mixture, and we need to correct for the overlap of emission
bands. The emissivity correction factor at
T = T
g
=
800 K is, from Fig. 1238,
0
.
0
6
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Mass, Heat, Radiation

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