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Influence of the interfacial thermal resistance of a gadolinium/copper bimetal composite on solid-state magnetic refrigeration.

Influence of the interfacial thermal resistance of a gadolinium/copper bimetal composite on solid-state magnetic refrigeration.

Authors :
Lu, Biwang
Huang, Yaoguang
Huang, Jiaohong
Ma, Zhihong
Wang, Jing
He, Jing
Source :
International Journal of Refrigeration. Sep2023, Vol. 153, p90-98. 9p.
Publication Year :
2023

Abstract

● The Gd/Cu bimetal composites are fabricated and interfacial layers are observed. ● Interfacial thermal resistance (ITR) is calculated based on thermal resistance test. ● Equivalent thermal conductivity is proposed to evaluate heat transfer capability. ● Reducing the ITR can significantly improve solid-state magnetic cooling performance. ● Combination of a topology-optimized structure and a reduced ITR is more beneficial. The low heat transfer efficiency caused by a magnetocaloric material (MCM) with low thermal conductivity is the bottleneck that limits the performance of magnetic refrigeration (MR). Previous studies have shown that a bimetal composite of a high thermal conductivity material and an MCM is effective in improving the heat transfer rate. However, the bimetal composite structure causes extra interfacial thermal resistance (ITR). Therefore, this study investigates the processing of gadolinium/copper bimetal composites by fusion casting and experimentally determines the ITR. To evaluate the structural heat transfer capability, the equivalent thermal conductivity (k eq) is proposed, which is calculated based on the ITR result and simulation. The influence of the ITR and k eq on the cooling performance of a fully solid-state MR is carefully investigated using a validated simulation model. The results show that the smallest ITR of 3.74 × 10−5 m2 K W −1 is obtained with a copper pouring temperature of 1200 °C owing to the thinnest bonding interfacial layer. The topology-optimized structure, using the ITR obtained by fusion casting, has an k eq of 159.8 W m −1 K −1, with an increase of 39% compared to the structure assembled with thermal grease. As a result, the maximum specific cooling power (SCP max) range and corresponding optimal operating range are significantly expanded to 45.6–209.3 W kg−1 and 0.23–0.61 rpm, respectively, with an average SCP max increase of 35.5%. The combination of using topology optimization design to reduce the structural thermal resistance and using a suitable forming process to reduce the ITR can be more beneficial to the performance improvement of solid-state MR. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01407007
Volume :
153
Database :
Academic Search Index
Journal :
International Journal of Refrigeration
Publication Type :
Academic Journal
Accession number :
173120725
Full Text :
https://doi.org/10.1016/j.ijrefrig.2023.06.025