Numerical investigation of melting of a phase-change material in H-type shell tubes

• Published in: Applied thermal engineering 2024-01, Vol.236, p.121470, Article 121470
• Main Authors: Chueh, Chih-Che, Hung, Shao-Che
• Format: Article
• Language: English
• Subjects: H-type fin arrangement; Melting process; Phase change material; Thermal energy storage
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2023.121470

Characteristics of flow vectors and temperature contours (A, C, F, H) as well as liquid fraction contours (B, D, E, G) are depicted for six identical H-type fin structures studied in this research. [Display omitted] •Phase-change material melting in an H-Type finned shell tube was examined.•There were two circular layers of each of the H-type fin structures.•Two varying curvy angles of each of the H-type fin structures were considered.•Temperature differences were observed between the outer and inner layers.•H-type fin structures favorably promoted the formation of natural convection. This study aims to numerically investigate the melting process of a phase change material in an H-type finned concentric shell tube configuration. The H-type fins are arranged in a manner that creates an annulus structure consisting of six identical H-type fin structures. These fins are evenly spaced with equal distances between them. The phase change material used in this study is RT42, which is stored within the annulus structure to absorb heat from the inner circular tube at a constant temperature input of 70 °C. The results of the study demonstrate that the phase change material within the H-type fin tube, with a uniform width of 3 mm, exhibit significantly faster melting rates compared to narrower fin tubes. Specifically, the phase change material in the 3 mm fin tube demonstrate melting rates that are 88% and 32% higher than those observed in fin tubes with widths less than 1 mm and 2 mm, respectively. Furthermore, the study considers two additional geometric factors, namely the varying curvy angles of the first and second circular layers of the H-type fins. Melting behavior is numerically featured by varying the ratios of these curvy angles within the range of 0.68 to 1.53. Among all the H-type annulus structures of the present study, the ratio of 1.21 is the most suitable design for increasing the total energy stored, while the ratio of 1.32 is an adequate choice for improving melting performance. Additionally, the latter ratio results in a 1.68 times reduction in melting time compared to the ratio of 1. Properly arranged H-type fin structures are possibly considered a preferable design that can either enhance heat transfer or increase the total stored energy, possibly expanding PCM applicability to a more latent heat thermal energy storage systems of practical interest.