ISSN Online: 2377-424X
International Heat Transfer Conference 12
Heat transfer enhancement and pressure drop for fin-tube bundles with winglet vortex generators
Аннотация
The objective of this research is to devise and test improved heat-transfer surfaces for fin-tube heat exchangers
such as air-cooled condensers used in binary-cycle geothermal power plants. A multiple-channel test core was
designed and fabricated for the determination of the overall heat transfer and pressure drop in various multipletube
geometry with circular tubes and winglet vortex generators. Heat-transfer results were obtained using a
transient method referred to as the modified single-blow method. The present research is to propose a novel
strategy that can augment heat transfer but nevertheless can reduce pressure loss in a fin-tube heat exchanger
with circular tubes in a relatively low Reynolds number flow, by deploying delta winglet-type vortex generators.
The triangular winglets in a fin-tube bundle in an inline arrangement successfully increase the overall heat
transfer by 10% to 20% and decrease the pressure drop by 8% to 15% for the Reynolds number (based on two times channel height) ranging from 350 to 2100, when the present winglets were built only in the first transverse
row of tubes. This innovative strategy for heat-transfer enhancement has been also validated, by measuring local
fin-surface temperature with an imaging infrared camera.