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Indexed by:期刊论文

Date of Publication:2016-07-01

Journal:INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

Included Journals:SCIE、EI、Scopus

Volume:75

Page Number:124-129

ISSN No.:0735-1933

Key Words:Heat transfer enhancement; Twisted tape; Dual-pipe heat exchanger

Abstract:In this paper, an experimental research was carried out to study the heat transfer and friction factor characteristics in a tube with a new kind of twisted tape insert. Four twisted tapes with different lengths (2400, 1800, 1200 and 600 mm) were used in the experimental study. The experimental data revealed that Nusselt number caused by these four twisted tapes were 1.45-1.90, 1.23-1.55, 1.18-1.45 and 1.15-1.37 times of that for the plain tube, while the values for friction factor were 3.69-5.75, 2.30-4.48, 2.15-2.75 and 1.21-1.31. The performance evaluation criteria (PEC) for length ratio of 1.0, 0.75, 0.50 and 0.25 is 0.94-1.06, 0.82-0.94, 0.89-1.04 and 0.89-1.06, respectively. What's more, correlations for Nusselt number and friction factor were established in the paper. The predicted values calculated by correlations were in good agreement with experimental data, within 7% for Nusselt number and within 10% for friction factor. (C) 2016 Elsevier Ltd. All rights reserved.