Melting of PCM: Correlations for Natural Convection Onset

摘要

The melting of an initially solid phase change material (PCM) starts with conduction heat transfer thatcontinues when the PCM starts melting. Natural convection in the melted PCM will take over conductioneventually. The question this paper answers is when and under what conditions is the onset of naturalconvection during melting happening? An experimental study was performed, in a cylindrical system, lookingat the impact of the central heat source diameter, the initial PCM temperature and the heat source temperature,for two PCMs, on the required melted PCM volume and time for the heat transfer mode to transitioned fromconduction to natural convection in the liquid PCM. From the experimental determination of the naturalconvection onset conditions, general correlations were obtained that predict the required volume of liquid PCMrequired for natural convection to start during the melting of a PCM.