Rayleigh–Bénard type PCM melting and solid drops

Abstract

In this paper we document both theoretically and numerically the melting of PCM in an enclosure heated from the bottom, in the presence of vertical metallic fins. We start with the analysis of the PCM melting in the absence of fins to discover the main scales of the problem, stressing the occurrence of Rayleigh-Bénard cells generated during the convection regime of melting. We continue with predicting the impact of fins on the development of the melting interface. The numerical experiments allow to understand the impact of the aspect ratio between the height of the enclosure and the distance between fins on the melting dynamics. They highlight the existence of solid drops for a certain range of aspect ratios when the horizontal flow channels in the convective loops along the fins become in contact, and they show how the solid drop is dragged downward to finish melting on the heated bottom of the enclosure.