Investigation Of Pressure Drop And Heat Transfer Behavior Of A Square Channel With 45° Angle Turbulators On One And Two Wall Configuration

Abstract

An experimental investigation of friction and heat transfer behavior for a fully developed flow in a square channel was conducted under a wide range of Reynolds numbers (Re) from 6,000 to 150,000. The heated test section was 22 hydraulic diameters (Dh) long, and made of four aluminum plates. The interior comprised of three smooth walls and one bottom wall roughened with glued brass ribs oriented at 45° to the flow direction with a ratio of rib height to channel hydraulic diameter (e/Dh), and ratio of pitch to rib height (p/e) of 0.063 and 10, respectively. A 20Dh long acrylic inlet channel, with geometry matching the test section’s interior, ensures that the flow becomes hydrodynamically developed before entering the test section. Heat transfer tests were conducted under isothermal wall conditions for Reynolds number ranging from 25,000 to 150,000. The results show that after x/Dh = 8.0, the heat transfer coefficient becomes constant, indicating that the heated flow is thermally developed at this point. When compared with Reynolds number, Nusselt number for each heated wall increases in a power law like fashion. The ribbed bottom wall achieves the most heat transfer, while the top smooth wall achieves the least. The left and right walls display comparable heat transfer trends, however the left wall prevails over the right wall because the ribs direct the flow toward the left wall, creating a slight impinging effect. Test section Nusselt number augmentation (Nu/Nu0) decreases, then levels out at value of 1.7 after a Reynolds number of 50,000. However, friction factor enhancement (f/f0), measured at Reynold numbers ranging from 6,000 to 150,000, increases linearly increasing Reynolds number, which reduces the overall thermal performance at higher Reynolds numbers.

Publication Date

1-1-2016

Publication Title

52nd AIAA/SAE/ASEE Joint Propulsion Conference, 2016

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.2514/6.2016-4855

Socpus ID

85088772460 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85088772460

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