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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL STUDY ON HEAT TRANSFER ENHANCEMENT AND FLOW STRUCTURE IN A TUBE WITH CENTRAL SLANT DEFLECTOR

Get access (open in a dialog) DOI: 10.1615/IHTC16.hte.023479
pages 5081-5086

摘要

In this work, a novel tube insert named central slant deflector is proposed for heat transfer enhancement, and numerical simulations are conducted to study the characteristics of heat transfer and friction factor of laminar water flow in a heat exchanger tube with Reynolds numbers ranging from 300 to 1500. The results reveal that the novel insert enhances heat transfer dramatically with acceptable increase of pressure drop by guiding flow from the core region to the boundary region and generating multiple longitudinal swirl flows. In addition, effects of the geometrical parameters, including the central angle, the slant angle and the pitch, are investigated numerically. Results indicate that the Nusselt number and friction factor both increase with the increase of slant angle, but decrease with the increase of pitch ratio. Higher Nuseelt number can be obtained when the central angle is 180°. In general, the Nusselt number is enhanced by 2.97-5.77 times when compared to that of a smooth tube, while the friction factor is 2.89-9.93 times. Furthermore, PEC is in the range of 2.02-2.74. Compared to some other inserts investigated in previous works, the insert proposed in this work is more effective in enhancing heat transfer, and has a better general performance, which may be of practical applications in the future.