ISSN Online: 2377-424X
ISBN Print: 0-89116-909-1
International Heat Transfer Conference 9
FILMWISE CONDENSATION OF R-113 ON HORIZONTAL INTEGRAL-FIN TUBES OF DIFFERENT DIAMETERS
Аннотация
Heat-transfer measurements are reported
for condensation of R-113 on a smooth tube
(outside diameter 19.05 mm) and on three
sets of finned tubes which differed only in
root diameter. The fin-root diameters were
12.7 mm, 19.05 mm and 25.0 mm. All fins
within a set of tubes had the same height
and thickness of 1 mm and spacings of 0.25
mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and 4.0
mm. In addition, a special tube ("QMC
tube") identical to one used by Masuda and
Rose (1985) was also tested for comparison
purposes. Data were taken at near-atmospheric pressure. Vapor-side, heat-transfer coefficients were determined using a "modified Wilson-plot" technique.
Results for the "QMC tube" were in excellent agreement with the earlier data of Masuda and Rose (1985), confirming the validity of both experimental measurements. Heat-transfer enhancement ratios revealed that, within the range of diameters tested, the effect of root diameter was small. A change in root diameter did not affect the optimum fin spacing which was near 0.5 mm. At this optimum fin spacing, enhancement ratios of 5.2, 5.2 and 5.6 were obtained for the small, medium and large diameter tubes, respectively.
Results for the "QMC tube" were in excellent agreement with the earlier data of Masuda and Rose (1985), confirming the validity of both experimental measurements. Heat-transfer enhancement ratios revealed that, within the range of diameters tested, the effect of root diameter was small. A change in root diameter did not affect the optimum fin spacing which was near 0.5 mm. At this optimum fin spacing, enhancement ratios of 5.2, 5.2 and 5.6 were obtained for the small, medium and large diameter tubes, respectively.