Numerical simulation of heat transfer characteristics of phase change materials enhanced with multi-angle fins. (June 2023)

• Record Type: Journal Article
• Authors: Zhu, Chuanhui; Luo, Quanquan; Yan, Shubin; Liu, Qian; Zhang, Wei
• Is Part Of: Journal of energy storage. Volume 62(2023)
• Publication Date: 2023-06
• Subjects: Evacuated tube -- Computational fluid dynamics -- Phase change material -- Regular geometry ribs -- Multi-angle fins -- Heat-storage rod; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2023.106914
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: In this paper, for the packaging structure of phase change materials (PCMs) for solar thermal utilization, a cylindrical phase-change heat-storage rod (HSR) is proposed, and multi-angle fins are designed to accelerate the melting rate of the PCM. Computational fluid dynamics (CFD) simulations were used to analyze the influences of different fin shapes on the melting characteristics of the PCM in the HSR, to calculate the melting time, temperature response rate, and average heat transfer coefficient of the PCM for each model, and to analyze the influences of different fin spacings and air flow rates on the melting of the PCM. Under the heat flow boundary condition of 800 W/m 2, it took 2813 s for the PCM of the finless HSR to melt completely. Among the 12 groups of fins designed, the Tra-45 fin model had the best performance, and the melting time of the PCM was 5.4 % shorter than that of the finless control group. In the Tra-45 model, the temperature distribution of the PCM was concentrated, and the maximum temperature increased by 6 °C. The temperature response rate of the Tra-45 model was 5 % higher than that of the control group, and the average heat transfer coefficient was 9.97 W/(m 2 ·K), 2.8 % higher than that of the control group. When 45° trapezoidal fins were added to the HSR, the melting rate of the PCM increased. The 60-mm model had the highest melting rate during the melting process, and the temperature distribution in the HSR was uniform. In addition, reducing the flow rate could increase the melting rate of the PCM. Highlights: Multi-angle fins were added to an HSR to enhance the heat transfer of PCMs. The Tra-45 model shortened the melting time and increase the heat storage of HSR. The heat transfer coefficient changed little with fins installed angle. Too narrow fin spacing will not promote the heat transfer of PCMs.