Experimental Study on Flow Friction and Heat Transfer in a Square-Duct Heat Exchanger with Winglet Turbulators

Abstract:

The paper presents an experimental study on airflow friction and heat transfer behaviors in a heat exchanger square-duct fitted with winglet turbulators. The experiments are carried out by varying the airflow rate in terms of Reynolds number from 4000 to 25,000. The winglets were mounted in tandem with three attack angles (α=30^o, 45^o and 60^o), two winglet-pitch to duct-height ratios, (called pitch ratio, PR=P/H=1.0 and 1.5) and a single winglet-to duct-height ratio, (called blockage ratio, BR=e/H=0.2). Effects of the winglet parameters on heat transfer and pressure loss in terms of Nusselt number and friction factor are investigated. The experimental result reveals that the application of the winglets provides considerably higher heat transfer and pressure loss values than the smooth duct alone. The winglet at α=60^o and PR=1 gives the maximum heat transfer and pressure loss but the one at α = 30^o and PR=1.5 yields the highest thermal enhancement factor of about 1.49 at the lowest Reynolds number.

• Periodical: Advanced Materials Research (Volumes 931-932)
• Pages: 1183-1187
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.931-932.1183
• Online since: May 2014
• Authors: Supattarachai Suwannapan, Panuwat Hoonpong, Pongjet Promvonge*, Sirisawat Juengjaroennirachon, Monsak Pimsarn
• Keywords: Friction Factor, Heat Transfer, Square-Duct Heat Exchanger, Winglet Turbulators

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