Chapter 12
Radiation Heat Transfer
1229
The base and the dome of a hemispherical furnace are maintained at uniform temperatures. The net
rate of radiation heat transfer from the dome to the base surface is to be determined.
Assumptions
1
Steady operating conditions exist
2
The surfaces are
opaque, diffuse, and gray.
3
Convection heat transfer is not considered.
Analysis
The view factor is first determined from
F
FF
F
11
11
12
12
0
11
=
+=
→=
(flat surface)
(summation rule)
Noting that the dome is black, net rate of radiation heat transfer
from dome to the base surface can be determined from
kW
759.4
=
×
=
−
⋅
×
−
=
−
−
=
−
=
−
W
10
594
.
7
]
)
K
1000
(
)
K
400
)[(
K
W/m
10
67
.
5
)(
1
](
/4
)
m
5
(
)[
7
.
0
(
)
(
5
4
4
4
2
8
2
4
2
4
1
12
1
12
21
π
σε
T
T
F
A
Q
Q
&
&
T
1
= 400 K
ε
1
= 0.7
T
2
= 1000 K
ε
2
= 1
D
= 5 m
The positive sign indicates that the net heat transfer is from the dome to the base surface, as expected.
1230
Two very long concentric cylinders are
maintained at uniform temperatures. The net rate of
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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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