Experimental study of solid-liquid phase change in the presence of supercooling and natural convection

This study experimentally investigates the supercooling and natural convection behavior in three PCM, namely pure octadecane (organic), a eutectic PCM, and sodium acetate trihydrate (inorganic). The aim is to explore the effect of different factors on the degree of supercooling and on the natural convection, and to provide data for numerical simulation models. Results show that the type of PCM, the temperature of the cooling fluid, and mechanical shocks have a direct effect on the degree of supercooling. The supercooled PCM shows a high sensitivity to any changes in the applied conditions. The thermal insulation of the unheated PCM boundaries has a major effect on the solidification and melting dynamics and topology, particularly regarding the solid-liquid interface. The cross-sectional temperature profiles, the inclination of the solid-liquid interface, and the melting rate show that regardless of the PCM, natural convection plays a significant role during heating but not during cooling.