Numerical Analysis of the Influence of Natural Convection on Melting and Solidification of Paraffin

Latent heat that is absorbed or released during solid-liquid phase change at constant or nearly constant temperature presents thermal potential that can be exploited for various purposes, from thermal energy storage to thermal management. Materials that undergo phase change are called phase-change materials (PCM), and one of the most commonly used PCMs is paraffin. For a long time, modeling change of state has been extremely difficult because tracking of the solid-liquid interface was limited to extremely simple and simplified cases. With the application of the enthalpy-porosity method, that does not track the interface explicitly, modeling has become easier and applicable to a variety of problems. This paper deals with a two-dimensional transient numerical analysis of heat transfer with melting and solidification of paraffin encased in a rectangular enclosure. Effects of natural convection have been studied for both melting and solidification process. Computational model has been validated with published numerical results and adequate agreement has been observed. It is evident that natural convection ; a buoyancy-driven motion of fluid that results in heat transfer between liquid and solid, is the dominant form of heat transfer in melting process and should be taken into account, while has little effect on solidification process, where conduction is the dominant mechanism.