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Boiling Heat Transfer 22
1
For the BWR operating parameters given below, compute and plot:
a)
The clad surface temperature assuming the JensLottes Correlation
b)
The clad surface temperature assuming the Thom Correlation
c)
The clad surface temperature assuming the Chen Correlation
You can neglect the mixed boiling region and assume the transition point from single phase forced convection to
nucleate boiling in the JensLottes and Thom Correlations occurs at that point
z
b
, such that
m
m
b
sat
c
b
b
z
q
T
h
z
q
z
T
1
1
6
10
)
(
)
(
)
(
⎟
⎠
⎞
⎜
⎝
⎛
′
′
+
=
′
′
+
−
∞
ς
i.e., the wall temperature is continuous at the transition point.
In the Chen correlation, substitute the Weisman
correlation for the DittusBoelter correlation in
o
h
A
.
Discuss your results.
BOILING WATER REACTOR PARAMETERS
Channel Heat Input
350,000 Btu/hr
Channel Mass Flux
1.42 x 10
6
lbm/hrft
2
Rod Pitch
0.640 inches
Rod Diameter
0.493 inches
Channel Pressure
1000 psia
Channel Height
146 inches
Inlet Temperature
532 F
⎟
⎠
⎞
⎜
⎝
⎛
⎟
⎠
⎞
⎜
⎝
⎛
′
′
′
′
H
z
H
H
z
H
q
z
q
)

(
sin
)

(
=
)
(
0
π
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View Full Document Boiling Heat Transfer 22
2
SOLUTION
The channel heat input defines the amplitude of the heat flux profile.
For
D
H
q
x
x
x
HD
q
Ddx
x
x
q
H
Ddz
H
z
H
H
z
H
q
Ddz
z
q
q
H
H
π
0
0
0
0
0
0
0
0
)]
cos(
)
[sin(
)
sin(
)
(
sin
)
(
)
(
′
′
=
−
′
′
=
′
′
=
⎟
⎠
⎞
⎜
⎝
⎛
−
⎟
⎠
⎞
⎜
⎝
⎛
−
′
′
=
′
′
=
∫
∫
∫
The amplitude of the heat flux profile is then
0
2
350,000
Btu
222,900
0.493 146
hrft
12
12
q
q
DH
′′
==
=
××
The fluid properties assumed for this problem are
f
ρ
= 46.318
g
= 2.242
f
μ
= 0.2327
g
= 0.047
f
k
= 0.3273
σ
= 0.0012
sat
T
= 544.58
f
h
= 542.6
fg
h
= 650.4
The coolant enters the channel subcooled, such that the potential exist for single phase forced convection over some
portion of the channel.
The outer clad surface temperature (in the absence of boiling) is given by
Tz Tz
q
z
h
co
c
()
=+
∞
where the
fluid temperature distribution is given by
∫
′
′
′
′
+
=
∞
∞
z
pf
z
Dd
z
q
C
m
T
z
T
0
)
(
1
)
0
(
)
(
±
or
Boiling Heat Transfer 22
3
⎥
⎦
⎤
⎢
⎣
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This note was uploaded on 12/08/2010 for the course NE 402 taught by Professor Doster during the Fall '08 term at N.C. State.
 Fall '08
 Doster

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