Numerical simulation of fin arrangements on the melting process of PCM in a rectangular unit

Abstract

Innovative fin arrangements were proposed to enhance the thermal performance of latent heat storage units. The enthalpy-porosity approach was employed to optimize the fin distribution and predict the transient melting behaviors of N-octadecane. The unit with horizontal fins of uniform length was set as the base condition for comparison. It was found that the dead space of heat transfer and melting due to natural convection was not effectively eliminated by the conventional fin set. The region persisted at the bottom of the unit until the end of the melting process. In light of these observations, the fins were repositioned and resized. Three alternative fin configurations were proposed and evaluated: angled fins, asymmetrically located fins, and stepped fins. Results illustrated that fin structures significantly influenced the heat transfer characteristics and melting behaviors of latent heat storage units. Generally, greater enhancements were attained with downward angles and downward offset distances. The downward angle −20°led to an accelerated melting rate of 18.3 % compared to the base condition. In case 9, where the fins were moved down by 12 mm, the heat transfer enhancement ratio reached 32.5 %. However, introducing inhomogeneity in the fin length had only a minimal impact on the melting process.