Investigation of Fractal Fins towards Heat Transfer Properties in Thermal Storage System

Abstract

To augment heat transfer in energy storage systems, fin inclusion is frequently adopted. This study critically examines various fin arrangements by employing a dimensionless parameter calculation method. Metrics of comparison include total melting time, dynamic temperature behavior, liquid fraction, and a unit performance indicator. The findings reveal that at Prandtl and Stefan numbers of unity, a Rayleigh number of 10⁴ demarcates the boundary between convective and conductive heat transfer, thus determining the dominant heat transfer mode. By reorienting the internal fins within a four-fin structure, we observed improved transfer performance at low Rayleigh numbers (Ra ≤ 10⁴); the liquid fraction approached unity with rising Rayleigh numbers. When assessing the unit performance metric, the reoriented four-fin structure manifested superior attributes in comparison to alternative configurations for Ra ≤ 5 × 10⁴. However, at higher Rayleigh numbers, complex fin structures impede heat convection, and the two-fin structure makes the more effective configuration.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China (No.52106120).

Notes on contributors

Bingbing Li

Bingbing Li received the B.S. degree in thermal energy and power engineering from China University of Mining and Technology, Xuzhou, China, in 2013 and the M.S. degree in  power engineering from the same university in 2015. She is currently working toward the Ph.D. degree in Fluid Dynamics with the School of Low-Carbon Energy and Power Engineering at the same university. Her research interests include energy storage, heat transfer enhancement and fluid dynamics.

Haowei Zhou

Haowei Zhou received the bachelor’s degree in low carbon energy and power engineering from China University of Mining and Technology, Xuzhou, China, in 2022. He started his master’s degree in fluid mechanics in 2022. His research interests include energy storage, heat transfer and flow characteristics research.

Yutao Huo

Yutao Huo received the B.S. degree in thermal energy and power engineering from China University of Mining and Technology, Xuzhou, China, in 2014, and the Ph.D. degree in power engineering from the same university in 2018. His research interests include energy storage, heat transfer enhancement and fluid dynamics.

Zhonghao Rao

Zhonghao Rao is a Professor and Dean of School of Energy and Environmental Engineering at Hebei University of Technology. He was shortlisted for 2020 Clarivate highly cited Researchers, 2021 Elsevier Highly Cited Chinese Researchers, and World’s Top 2% Scientists 2022. He serves on the editorial board of several journals. He has also served as the session chair or cochairmen of several international conferences. His topics of research interest include energy storage, battery thermal management, thermal safety, multiphase flow and heat transfer enhancement. He has over 150 publications in peer reviewed international journals. The total citations are more than 6700/9700 (source: Web of Science/Google Scholar), and h-index is 41/51.