Convective heat transfer enhancement by combination effect of twist and helix in helical twisted tubes

IF 5.1 3区工程技术 Q2 ENERGY & FUELS

Thermal Science and Engineering Progress Pub Date : 2025-03-11 DOI:10.1016/j.tsep.2025.103504

Mengxuan Wang , Xiuzhen Li , Yingying Tan , Lin Wang , Yan Peng , Zhanwei Wang

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引用次数: 0

Abstract

A novel heat exchange element-helical twisted tube (HTT) is proposed, and its novelty is reflected in the heat transfer enhancement brought about by the coupled deformation effect of helix and twist. Numerical simulations are used to research the effects of structural parameters on heat transfer, flow resistance, and entropy production characteristics of the HTT within the Reynolds number (Re) range of 500 to 4000 at constant wall temperature, which the mathematical model adopted is the RNG k-ε turbulence model. The variations of Nusselt number (Nu), friction factor (f), entropy production (S^’_gen), Bejan number (Be), and performance evaluation criterion (PEC) in the HTT are analyzed with respect to changes in twist ratio (Y), diameter ratio (D/D_h), and helical pitch ratio (x/D_h). The results turn out that the rising Re brings about the increase of Nu and S^’_gen; but results in the decrease of f and Be. Under the condition of constant Re, the values of Nu, f, and S^’_gen exhibit a decreasing trend as Y increases. This decremental behavior is also observed when D/D_h rises, and furthermore, all these parameters decrease as x/D_h increases. The Be within HTT increases with an increase in Y, D/D_h, and x/D_h. When Re is constant, the secondary flow intensity in HTT is 32.0 % higher than spiral circular tube (SCT) and 183.1 % higher than twisted elliptical tubes (TET). The heat transfer efficiency in HTT increased by 14.9 % compared to SCT and by 33.7 % compared to TET. Within the research scope, Case 8 (B = 100 mm, D = 30 mm, x = 176.4 mm) is identified as the optimal HTT.

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来源期刊

Thermal Science and Engineering Progress Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

7.20

自引率

10.40%

发文量

327

审稿时长

41 days

期刊介绍： Thermal Science and Engineering Progress (TSEP) publishes original, high-quality research articles that span activities ranging from fundamental scientific research and discussion of the more controversial thermodynamic theories, to developments in thermal engineering that are in many instances examples of the way scientists and engineers are addressing the challenges facing a growing population – smart cities and global warming – maximising thermodynamic efficiencies and minimising all heat losses. It is intended that these will be of current relevance and interest to industry, academia and other practitioners. It is evident that many specialised journals in thermal and, to some extent, in fluid disciplines tend to focus on topics that can be classified as fundamental in nature, or are ‘applied’ and near-market. Thermal Science and Engineering Progress will bridge the gap between these two areas, allowing authors to make an easy choice, should they or a journal editor feel that their papers are ‘out of scope’ when considering other journals. The range of topics covered by Thermal Science and Engineering Progress addresses the rapid rate of development being made in thermal transfer processes as they affect traditional fields, and important growth in the topical research areas of aerospace, thermal biological and medical systems, electronics and nano-technologies, renewable energy systems, food production (including agriculture), and the need to minimise man-made thermal impacts on climate change. Review articles on appropriate topics for TSEP are encouraged, although until TSEP is fully established, these will be limited in number. Before submitting such articles, please contact one of the Editors, or a member of the Editorial Advisory Board with an outline of your proposal and your expertise in the area of your review.