Enhancing turbulent heat transfer and flow characteristics in ribbed channels with periodic slits: A comparative study of transverse, inclined, and V-shaped configurations

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-11-10 DOI:10.1016/j.ijthermalsci.2024.109531

Dehai Kong , Shuo Ren , Sergey Isaev , Cunliang Liu , Song Liu , Xiying Niu

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Abstract

In this study, we experimentally investigate the turbulent heat transfer characteristics of rectangular channels equipped with miniature transverse, inclined, and V-shaped ribs, each incorporating various types of periodical slits. These slits, located between the lower wall of the rib and the bottom wall of the channel, create different slit channels (confusor, diffusor, and constant cross-section). The rib blockage ratio and the pitch to rib height ratio were kept at 0.032 and 10, respectively. To measure the local heat transfer characteristics on the bottom ribbed wall at Reynolds numbers varying from 40,000 to 120,000, the transient thermochromic liquid crystal (TLC) method was employed. In addition, the k-ω SST turbulence model was used to simulate the spatial turbulent flow behaviours in rectangular channels with slit ribs to reveal the heat transfer mechanism. The results indicate that the configuration of miniature ribs, along with the type and position of slits, significantly affects the heat transfer and friction loss of the rectangular channel. Opening periodical slits on the ribs reduces the pressure drop of the ribbed channel while exerting various influences on heat transfer performance due to complex vortex structures induced by the ribs and slits, which affect the secondary flow intensity. The highest average augmentation Nusselt number and thermal-hydraulic performance (THP) were observed in channels with V-shaped solid ribs, achieving values up to 2.5 and 1.7 at Re = 40,000. Lastly, we established experimental correlations for the overall averaged Nusselt number and friction characteristics specific to the slit ribbed channels.

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利用周期性狭缝增强带肋水道中的湍流传热和流动特性：横向、倾斜和 V 形结构的比较研究

在本研究中，我们通过实验研究了装有微型横向、倾斜和 V 型肋条的矩形通道的湍流传热特性，每种肋条都包含各种类型的周期性狭缝。这些狭缝位于肋条下壁和通道底壁之间，形成不同的狭缝通道（混流通道、扩散通道和恒定截面通道）。肋条阻塞比和间距与肋条高度比分别保持为 0.032 和 10。为了测量雷诺数在 40,000 到 120,000 之间时底部肋壁的局部传热特性，采用了瞬态热致变色液晶（TLC）方法。此外，还采用 k-ω SST 湍流模型模拟了带有狭缝肋条的矩形水道中的空间湍流行为，以揭示传热机理。结果表明，微型肋条的配置以及缝隙的类型和位置对矩形水道的传热和摩擦损失有显著影响。在肋条上开设周期性狭缝可降低带肋通道的压降，同时由于肋条和狭缝诱发的复杂涡流结构对传热性能产生各种影响，从而影响二次流强度。在带有 V 形实心肋条的通道中，观察到了最高的平均增强努塞尔特数和热流性能（THP），在 Re = 40,000 时分别达到了 2.5 和 1.7。最后，我们还建立了针对狭缝带肋水道的整体平均努塞尔特数和摩擦特性的实验相关性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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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.