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Title:An assessment of fin-tube thermal contact resistance in round-tube-plain-fin heat exchangers
Author(s):Cortes, Maria
Department / Program:Mechanical Sci & Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Contact resistance
Fin-tube heat exchanger
Abstract: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.
Issue Date:2015-04-29
Rights Information:Copyright 2015 Maria Cortes
Date Available in IDEALS:2015-07-22
Date Deposited:May 2015

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