Tenclosure
H
3.94 in.
(Y)
Tpipe
23.6 in.
1.12-in. diameter (D)
55.4F ≤ Tenclosure ≤ 62.6F
3.94 in.
Tpipe ≤ 104F
Figure 6. Experimental apparatus of Babus'Haq et al. (1986).
where the characteristic lengths G and D are the average vertical gap width,
(YD) /2, and the pipe diameter, respectively. This equation can be converted to
the following form using their test conditions:
NuL = 0.4048RaL.25 .
0
(49)
Additionally, they found that the optimal location for a heated pipe in a cooled
square enclosure is in the upper part of the enclosure, specifically at E = 0.73, where
E is the eccentricity given by
2H
E=
-1
(50)
Y - D
and H is the distance from the top of the pipe to the inside of the enclosure lid. Y is
the interior vertical dimension and D is the pipe diameter. Figure 7 compares the
103
eq 42
eq 44
eq 47
102
eq 46
eq 49
eq 43
eq 45
101
8
9
10
11
10
10
10
10
Rayleigh Number
Figure 7. Heat transfer equations for pipes in enclosures.
10
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