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Cortes, Maria 2015-07-22T22:17:56Z 2015-07-22T22:17:56Z 2015-05 2015-04-29 Fin-and-tube heat exchangers are used in a wide variety of applications. Heat exchangers with expanded tubes are economical, but a drawback is the potentially large contact resistance between tubes and fins. Previous studies have investigated this topic under the exclusion of air-side convection. The present work is more realistic, because the contact resistance is evaluated in the presence of air-side convection. The goal of this experimental work is to determine the contribution of the contact resistance to the overall heat transfer resistance in round-tube-plain-fin heat exchangers. The four samples have copper tubes with two different expansion ratios and aluminum fins with collars of two different lengths. The heat exchangers were examined in a wind tunnel under dry and frosted conditions to determine the contact resistance. The frosted heat exchangers are used as a baseline, because frost growth bridges the gaps between fins and tubes. The contact resistance was much higher for the unexpanded heat exchangers – about 30-60% of the overall resistance, whereas expanded heat exchangers exhibited a contact resistance of about 10-30% of the overall resistance. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms The student, Maria Cortes, accepted the attached license on 2015-04-28 at 11:37. The student, Maria Cortes, submitted this Thesis for approval on 2015-04-28 at 11:45. This Thesis was approved for publication on 2015-04-29 at 15:50. DSpace SAF Submission Ingestion Package generated from Vireo submission #8150 on 2015-07-22 at 10:34:23 Made available in DSpace on 2015-07-22T22:17:56Z (GMT). No. of bitstreams: 3 CORTES-THESIS-2015.pdf: 2015974 bytes, checksum: 7b6fa72bacd8839bf7b221b999940e87 (MD5) Cortes_Maria_thesis.docx: 5160354 bytes, checksum: 79ace0066d09306aefe5a64e07bc34cc (MD5) LICENSE.txt: 4209 bytes, checksum: d1ef7fc7056efa9a3902a6ca82016418 (MD5) Previous issue date: 2015-04-29 application/pdf http://hdl.handle.net/2142/78523 en Copyright 2015 Maria Cortes Contact resistance Fin-tube heat exchanger An assessment of fin-tube thermal contact resistance in round-tube-plain-fin heat exchangers text text 2015-5 Mechanical Sci & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Thesis M.S.