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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Heat transfer enhancement and pressure drop for fin-tube bundles with winglet vortex generators

Get access (open in a dialog) DOI: 10.1615/IHTC12.1100
6 pages

Sinopsis

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.