Heat Transfer During Melting from a Vertical Cylinder : 2nd Report, Effects of Aspect Ratio of the Cylinder and Subcooling

Abstract

Experiments and numerical analysis of the melting around a vertical cylinder with or without subcooling were carried out, using different cylinder diameters. In the experiments n-octanecane was used as a phase change material (PCM). The measured shapes of the melting front agreed well with the analytical results. In the analysis the laminar natural convection in the liquid phase and the heat conduction in the solid phase were calculated simultaneously by means of a finite difference method. The subcooling degree significantly depresses the melting rate. The subcooling degree decreases the rate of the total thermal energy storage when it is large. The relation between the average Nusselt number on the cylinder and the average thickness of melt region does not depend on the subcooling degree. The melting volumes with different cylinder diameters without subcooling are arranged by a non-dimensional time including the aspect ratio of the cylinder.