Numerical study on unsteady heat transfer characteristics of phase change plates optimized by fin structure

The energy crisis has heightened the importance of phase change energy storage technology as a key enabler for orderly energy transformation. However, the density variation of phase change materials during phase transition is often overlooked, leading to issues such as reduced heat transfer efficiency and local overheating. To mitigate the consequent density stratification, this study employs numerical simulations to investigate the integration of fin structures into a phase change plate. Specifically, the inhibitory effects of fin length, the number of transverse fins, and the presence of longitudinal fins on melting stratification are analyzed. The main results are as follows: (1) The plain phase change plate (without fins) showed an abrupt temperature rise followed by stabilization during melting, with a concurrent shift in its liquid fraction curve; (2) Increases in fin length, transverse fin number, and longitudinal fin number all improved the plate's melting rate and temperature uniformity, with maximum improvements of 10.86% and 293%, respectively; (3) optimization method 1 delivered a superior effect but was associated with a higher initial cost compared to optimization method 2.