Multi-field coupling analysis of thermochemical energy storage reactor with prepared Mg(OH)2/expanded graphite composites

IF 5.8 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer Pub Date : 2025-09-27 DOI:10.1016/j.ijheatmasstransfer.2025.127873

Xueming Yang , Weichen Liang , Haiqi Xu , Jianing Chen , Jianfei Xie

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引用次数: 0

Abstract

Mg(OH)₂/MgO thermochemical energy storage(TCES) system becomes more attractive in the field of solar thermal utilization, but the coupling mechanism between the reaction kinetics and heat and mass transfer has not been fully explored. In this paper, Mg(OH)₂/expanded graphite (EG) thermochemical energy storage composites were first prepared using the wet ball milling method, focusing on the reaction kinetics of the dehydration process. It was found that the rehydration rate remained above 80 % after multiple cycles. Next, numerical simulations of the dehydration and hydration processes in the reactor filled with the Mg(OH)₂/EG composites were carried out to reveal the mechanism of the multi-physical field coupling of the chemical reactions. The results show that the improvement of the thermal conductivity of the composites enhances the heat transfer in the reactor and makes the temperature distribution of the composites more uniform, leading to significant reduction of the reaction time and an increase of 68.3 % in the thermal charge power compared to that of pure Mg(OH)₂ used. By introducing a gradient porosity structure to optimize the mass transfer characteristics of the reactor, the dehydration/hydration performance can be significantly improved compared to a fixed porosity. The direct benefits include reduced reaction time by 19.7 % and 39.5 % and reduced average pressure by 7.5 % and 82.2 %. Particularly, the average thermal charging/discharge power is increased by 11.1 W and 1.9 W, respectively.

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制备的Mg(OH)2/膨胀石墨复合材料热化学储能反应器多场耦合分析

Mg(OH)2/MgO热化学储能（TCES）系统在太阳能热利用领域越来越受到关注，但其反应动力学与传热传质之间的耦合机理尚未得到充分探讨。本文首次采用湿球磨法制备了Mg(OH)2/膨胀石墨（EG）热化学储能复合材料，重点研究了其脱水过程的反应动力学。经多次循环后，复水率保持在80%以上。其次，对Mg(OH)2/EG复合材料在反应器内的脱水和水化过程进行了数值模拟，揭示了化学反应的多物理场耦合机理。结果表明：复合材料导热系数的提高增强了反应器内的传热，使复合材料的温度分布更加均匀，反应时间明显缩短，热装功率比纯Mg(OH)2提高了68.3%。通过引入梯度孔隙结构来优化反应器的传质特性，与固定孔隙度相比，脱水/水化性能显著提高。直接效果是反应时间分别缩短19.7%和39.5%，平均压力分别降低7.5%和82.2%。其中，平均热充放电功率分别提高了11.1 W和1.9 W。

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 Heat and Mass Transfer 工程技术-工程：机械

CiteScore

10.30

自引率

13.50%

发文量

1319

审稿时长

41 days

期刊介绍： International Journal of Heat and Mass Transfer is the vehicle for the exchange of basic ideas in heat and mass transfer between research workers and engineers throughout the world. It focuses on both analytical and experimental research, with an emphasis on contributions which increase the basic understanding of transfer processes and their application to engineering problems. Topics include: -New methods of measuring and/or correlating transport-property data -Energy engineering -Environmental applications of heat and/or mass transfer