Indirect measurement of local condensing heat-transfer coefficient around horizontal finned tubes

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Author
Lester, Donald J. Jr.
Date
1987-09Advisor
Marto, P.J.
Wanniarachchi, A.S.
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Show full item recordAbstract
Heat-transfer measurements were made for condensation of
steam on three finned tubes with rectangular-section fins.
These tubes have a fin thickness and fin height of 1.0 mm and
fin spacings of 0.5, 1.0 and 1.5 mm. Data were taken by insulating
both the inner and outer surfaces over up to 5 or 6
angular portions, including 0, 30, 60, 90, 150, 210 degrees,
of the top portion of each tube. The measured average heattransfer
coefficients for the unblanked portion of the tube
were processed to yield both the local and average heattransfer
performance as a function of the angle measured from
the top of the tube using a third-order polynomial.
The results show that the average enhancement for the fin
spacings of 0.5, 1.0 and 1.5 mm were 2.5, 3.0 and 3.1,. respectively,
for the atmospheric-pressure condition. And they
were 1.8, 2.3 and 2.4 for the low-pressure condition. The
local enhancements at the top of tubes were 5.2 and 3.8 for
s = 0.5 mm, 6.6 and 4.8 for 3=1.0 mm, and 6.6 and 5.5 for
s = 1.5 mm at atmospheric and low pressures, respectively.