{"title":"Enhanced thermal performance of mini-tube with chained-jet-chamber insert","authors":"Zhaoxuan Liu, Li Shan, Wenming Li","doi":"10.1016/j.ijthermalsci.2025.109701","DOIUrl":null,"url":null,"abstract":"<div><div>Significantly enhanced thermal performance of mini-tubes is of vital importance to achieve high efficiency of heat exchangers. While existed studies have comprehensively investigated various inserts with an aim to enhance heat exchange performance by disrupting the core flow of mini-tube, the limitation of strong fluid mixing within the boundary layer remains unresolved. Herein, a novel chained-jet-chamber insert was proposed to generate strong jetting flow in the vertical direction of fluid flow. Therefore, fluid flow boundary layer was substantially disturbed, leading to the significant enhancement of heat exchange. Numerical investigation was conducted to characterize heat transfer characteristics of this as-designed mini-tube inserted with a chained-jet-chamber for Reynolds number (<em>Re</em>) changing from 200 to 1200. Numerical results show that the overall Nusselt number (<em>Nu</em>) is substantially improved to about 180 at a Re of 1200 with a significant enhancement of 5.5-fold compared to the tube without insert owing to the intense spatial fluid mixing induced by the strong jetting flows. To evaluate the overall effectiveness of this proposed insert, the performance evaluation criteria (PEC) was calculated. A value of 2.6 is presented at a Re of 200. In contrast, the PECs of the twisted tape and helical screw tape are 1.6 and 1.9, respectively. To conclude, this novel chained-jet-chamber insert completely outperforms the twisted tape and helical screw tape inserts by generating spatial fluid mixing. This new solution can significantly increase the efficiency of compact heat exchangers in practical applications.</div></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":"211 ","pages":"Article 109701"},"PeriodicalIF":5.0000,"publicationDate":"2025-05-01","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/S1290072925000249","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/1/13 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Significantly enhanced thermal performance of mini-tubes is of vital importance to achieve high efficiency of heat exchangers. While existed studies have comprehensively investigated various inserts with an aim to enhance heat exchange performance by disrupting the core flow of mini-tube, the limitation of strong fluid mixing within the boundary layer remains unresolved. Herein, a novel chained-jet-chamber insert was proposed to generate strong jetting flow in the vertical direction of fluid flow. Therefore, fluid flow boundary layer was substantially disturbed, leading to the significant enhancement of heat exchange. Numerical investigation was conducted to characterize heat transfer characteristics of this as-designed mini-tube inserted with a chained-jet-chamber for Reynolds number (Re) changing from 200 to 1200. Numerical results show that the overall Nusselt number (Nu) is substantially improved to about 180 at a Re of 1200 with a significant enhancement of 5.5-fold compared to the tube without insert owing to the intense spatial fluid mixing induced by the strong jetting flows. To evaluate the overall effectiveness of this proposed insert, the performance evaluation criteria (PEC) was calculated. A value of 2.6 is presented at a Re of 200. In contrast, the PECs of the twisted tape and helical screw tape are 1.6 and 1.9, respectively. To conclude, this novel chained-jet-chamber insert completely outperforms the twisted tape and helical screw tape inserts by generating spatial fluid mixing. This new solution can significantly increase the efficiency of compact heat exchangers in practical applications.
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.
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