Table 3. Comparison of view-
Table 4. Comparison of radi-
factor calculations.
ation heat fluxes.
Surface 1
Heat flux, Btu/hr
to surface:
FEVIEW
Algebraic
Surface no. Algebraic Numerical
1
0.000000
0.000000
1
49.33
49.33
2
0.000000
0.000000
2
64.58
64.58
3
0.000000
0.000000
3
85.71
85.71
4
0.000000
0.000000
4
112.47
112.47
5
0.000000
0.000000
5
112.47
112.47
6
0.000000
0.000000
6
85.71
85.71
7
0.000000
0.000000
7
64.58
64.58
8
0.000000
0.000000
8
49.33
49.33
9
0.004405
0.004404
9
98.66
98.66
10
0.012544
0.012548
10
111.42
111.42
11
0.018935
0.018936
11
111.42
111.42
12
0.023108
0.023104
12
99.32
99.32
13
0.015429
0.015427
13
49.33
49.33
14
0.021588
0.021589
14
64.58
64.58
15
0.030854
0.030855
15
85.71
85.71
16
0.044708
0.044707
16
112.47
112.47
17
0.064495
0.064496
17
112.47
112.47
18
0.089417
0.089417
18
85.71
85.71
19
0.112962
0.112962
19
64.58
64.58
20
0.123106
0.123106
20
49.33
49.33
21
0.019586
0.019586
21
99.32
99.32
22
0.036895
0.036893
22
111.42
111.42
23
0.089073
0.089075
23
111.42
111.42
24
0.292893
0.292893
24
99.32
99.32
Sum
0.999998
0.999998
Sum
0.66
0.66
EXPERIMENTAL PROCEDURE
Experimental apparatuses
Two 10-ft-long experimental appara-
tuses were constructed to simulate sec-
tions of typical rectangular utilidors. The
first had an internal 1-ft 1-ft square cross
section; the second was 2 ft 4 ft. Figure
14 is the square cross section apparatus
with its lid off, with a 4-in. nominal diam-
eter pipe installed. Heat transfer panels
surrounded the sides of the enclosures
and a coolant was pumped through them.
The interior pipe was filled with high
temperature hydraulic oil and heated by
an internal, 10-ft-long, 1-kilowatt heating
element. The interior of the enclosure was
lined with plywood and expanded poly-
styrene (EPS) insulation; the conductivity
of two samples of the EPS was measured
according to ASTM standards using a
Rapid K apparatus. The results of these
tests are plotted in Figure 15. Thermo-
Figure 14. 1-ft 1-ft experimental appa-
couples were placed on either side of the
EPS when installed in the apparatus. The
ratus without lid.
24
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