Experimental and Computational Study of Melting of Paraffin Wax Inside a Cylindrical Capsules of Elliptical Cross Section

Abstract

This paper focuses on the melting of phase change material capsulated in the elliptical cross-section horizontal cylinder under convective boundary conditions. Different parameters are discussed namely, the HTF inlet temperature and velocity and the aspect ratio of the capsule cross-section. The effect of HTF inlet temperature, inlet velocity, and encapsulant aspect ratio was studied using the CFD software FLUENT6.3.26. A comparison between the numerical and experimental results was made for the system. The experimental results matched well with the heat transfer model. It is shown that the inlet temperature of the heat transfer fluid (HTF) has a great effect on the process of paraffin wax melting. The increase of HTF inlet temperatures increases the PCM liquid fraction and decreases at the same time the total time of melting the capsulated paraffin wax. The geometry of the capsule cross-section represented by its aspect ratio has a sensible effect on the process of paraffin wax melting. Decreasing the aspect ratio of the capsule, i.e elongated the capsule in the direction of flow increasing the PCM liquid fraction and decreases the total time of melting the capsulated paraffin wax. The increase of HTF inlet velocity has a very weak effect on the process of paraffin wax melting.