Enhancing latent heat storage dynamics with expanded graphite foam: Myth vs. reality check through numerical and experimental investigations

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-04-19 DOI:10.1016/j.ijthermalsci.2025.109929

Narender Kumar , Amit Shrivastava , Sandip K. Saha , Prodyut R. Chakraborty

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引用次数: 0

Abstract

The solid–liquid phase transition, with its moderate latent heat absorption or release over a narrow temperature margin and minimal density difference, finds extensive use in various thermal engineering applications such as energy storage, electronics cooling, and personal cooling. Commonly used organic or inorganic phase change materials (PCM) suffer from low thermal conductivity, which can be addressed by composite PCMs (CPCM). CPCMs comprise highly porous compressed-expanded graphite (CEG) foam impregnated with PCM. While CPCM shows significantly improved thermal conductivity, porous CEG foam in CPCM suppresses free convection during the melting process, making the heat transfer mostly diffusion-dominated. Our study compares free convection-dominated melting of pure PCM with diffusion-dominated melting of CPCM, conducted through numerical and experimental analysis in a bottom-heated rectangular cavity. From this investigation, we find that CPCM offers significantly better temperature uniformity, leading to the eradication of potential hot spots, and is advantageous for heat sink applications. However, CEG volume fraction in CPCM above or below a specific range hampers the fast melting process in thermal storage applications in contrast to the conventional notion.

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用膨胀石墨泡沫增强潜热储存动力学：通过数值和实验调查的神话与现实检验

固液相变具有在较窄的温度裕度和最小的密度差范围内吸收或释放潜热适中的特点，广泛应用于各种热工应用，如储能、电子冷却和个人冷却。常用的有机或无机相变材料（PCM）存在导热系数低的问题，复合相变材料（CPCM）可以解决这一问题。cpcm由浸渍PCM的高多孔压缩膨胀石墨（CEG）泡沫组成。CPCM的热导率明显提高，但CPCM中的多孔CEG泡沫在熔化过程中抑制了自由对流，使得传热以扩散为主。本研究通过在底部加热的矩形腔中进行数值和实验分析，比较了纯PCM的自由对流主导熔化和扩散主导熔化。通过研究，我们发现CPCM提供了更好的温度均匀性，从而消除了潜在的热点，有利于散热器的应用。然而，与传统观念相反，CPCM中CEG体积分数高于或低于特定范围会阻碍储热应用中的快速熔化过程。

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.