Thermal characteristics of a double-tube heat exchanger with different twist directions of the inner oval tube

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL International Journal of Thermal Sciences Pub Date : 2024-10-30 DOI:10.1016/j.ijthermalsci.2024.109481

KeWei Song , Zhen Tian , Xiang Wu , Qiang Zhang , Kun Zhang , BingDong Gu

{"title":"Thermal characteristics of a double-tube heat exchanger with different twist directions of the inner oval tube","authors":"KeWei Song , Zhen Tian , Xiang Wu , Qiang Zhang , Kun Zhang , BingDong Gu","doi":"10.1016/j.ijthermalsci.2024.109481","DOIUrl":null,"url":null,"abstract":"<div><div>A new configuration featuring an inner oval tube with alternating twist directions is proposed to improve the thermal performance of double-tube heat exchangers. This design enhances the heat transfer efficiency by inducing longitudinal vortices within the annular space, thereby disrupting the boundary layer on the heat transfer surface, promoting fluid mixing, and significantly augmenting heat transfer. Numerical simulations were conducted to investigate the effects of alternating twist directions of the inner oval tube on thermal performance. The results demonstrate that alternating twist direction of the inner tube creates more pronounced vortices, significantly enhances heat transfer performance compared with the conventional tubes. This novel oval tube led to a substantial enhancement of up to 173.6 % in the <em>Nu</em>, with a corresponding increase of 96.4 % in the <em>f</em>. At <em>Re</em> = 2600, the highest thermal performance factor of the reported annular tube with an alternately twisted oval inner tube can reach up to 2.18, indicating a 118 % improvement in overall heat transfer performance. Fitted correlations for <em>Nu</em> and <em>f</em> are provided to facilitate engineering applications.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"208 ","pages":"Article 109481"},"PeriodicalIF":4.9000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Thermal Sciences","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1290072924006033","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}

引用次数: 0

Abstract

A new configuration featuring an inner oval tube with alternating twist directions is proposed to improve the thermal performance of double-tube heat exchangers. This design enhances the heat transfer efficiency by inducing longitudinal vortices within the annular space, thereby disrupting the boundary layer on the heat transfer surface, promoting fluid mixing, and significantly augmenting heat transfer. Numerical simulations were conducted to investigate the effects of alternating twist directions of the inner oval tube on thermal performance. The results demonstrate that alternating twist direction of the inner tube creates more pronounced vortices, significantly enhances heat transfer performance compared with the conventional tubes. This novel oval tube led to a substantial enhancement of up to 173.6 % in the Nu, with a corresponding increase of 96.4 % in the f. At Re = 2600, the highest thermal performance factor of the reported annular tube with an alternately twisted oval inner tube can reach up to 2.18, indicating a 118 % improvement in overall heat transfer performance. Fitted correlations for Nu and f are provided to facilitate engineering applications.

查看原文

微信好友朋友圈 QQ好友复制链接

本刊更多论文

内椭圆管扭转方向不同的双管热交换器的热特性

为了提高双管热交换器的热性能，我们提出了一种新的结构，其特点是内椭圆管具有交替的扭曲方向。这种设计通过在环形空间内诱发纵向涡流来提高传热效率，从而破坏传热表面的边界层，促进流体混合，显著增强传热效果。我们进行了数值模拟，以研究椭圆形内管交替扭曲方向对热性能的影响。结果表明，内管的交替扭曲方向会产生更明显的涡流，与传统管道相比，能显著提高传热性能。在 Re = 2600 条件下，报告的带有交替扭曲椭圆形内管的环形管的最高热性能系数可达 2.18，表明整体传热性能提高了 118%。为方便工程应用，提供了 Nu 和 f 的拟合相关性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文去求助

来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.