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ACRC Technical Report 122PDF


Title:An Experimental Study of Flow and Heat Transfer in Wavy Passages
Author(s):Rush, T.A.; Jacobi, A.M.; Newell, T.A.
Subject(s):wavy fins
heat transfer augmentation
Abstract:Wavy passages are one of the many devices being considered by manufacturers in the HV ACIR industry to increase the air-side heat transfer coefficient for a variety of heat exchanger applications. The purpose of this research is to obtain a better understanding of the flow instabilities and heat transfer in wavy passages so that design guidelines may be developed. Flow visualization experiments on twelve different geometries revealed the flow patterns and behavior in laminar wavy-channel flow. At low Reynolds numbers, there is evidence of macroscopic mixing between the core flow and the near-wall fluid. The onset location of this macroscopic mixing moves closer to the entrance of the channel with increasing Reynolds number. The instabilities in the cp=180° geometry appear to be fundamentally different from the instabilities in the cp=O° and the cp=90° geometries. A parametric study revealed that for a given Reynolds number, instabilities in the cp=00 and the cp=90° geometries occur at a farther upstream location than in the cp=180° geometries. Relative wavelength did not affect channel performance in the experimental range. An increase in the relative amplitude of the channel delayed the intial onset of instability in the wavy passage, but had little effect as the location of the onset of instabiltiy moved closer to the entrance of the channel. Heat transfer experiments confirmed that the instabilities observed in the flow visualization experiments enhance heat transfer. The results of this research may help in determining wavy channel geometries with high heat transfer rates for a particular application.
Issue Date:1997-07
Publisher:Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
Series/Report:Air Conditioning and Refrigeration Center TR-122
Genre:Technical Report
Sponsor:Air Conditioning and Refrigeration Project 65
Date Available in IDEALS:2009-04-24
Identifier in Online Catalog:4159579

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