PCM heating transfer characteristics in a sidewall-heated rectangular cavity with non-contact metal fin

Thermal performance of phase change processes in a sidewall-heated rectangular cavity with non-contact metal fin was experimentally and numerically investigated in detail. In contrast to the contacting fin design, the non-contact fin design removes the requirement of connecting the fin to the heat source and consequently prevents contact thermal resistance. Natural convection caused by temperature difference leads to heat accumulation in the upper region of cavity and establishes a distinct thermal stratification, resulting in an insufficiently melted dead zone. A non-contact metal fin enables the transfer of heat from the high-temperature fluid to the bottom dead zone. The results indicated that the phase change thermal storage unit with an aspect ratio of 1:1.1, a dimensionless fin height of 1 and a dimensionless fin position of 1/6 achieves the best heat transfer performance. It can reduce melting time by 16.7 % and increases the heat transfer rate by 13.6 % when it is compared to a non-fin structure. Furthermore, for the Stefan number from 0.17 to 0.46, a 250.2 % increase in the average heat transfer rate is achieved, along with a 66.5 % drop in melting time. Finally, an experimental correlation of Nusselt number and RaSte number is established to provide guidance for the optimal design of the phase change thermal storage unit with non-contact fin.