Numerical Studies for Charging and Discharging Characteristics of Composite Phase Change Material in A Deep and Shallow Rectangular Enclosure

Abstract

In this study, a numerical analysis of the melting process with natural convection in a rectangular enclosure has been performed using enthalpy porosity model. A Composite phase change material (Paraffin wax (98%) is used as base material and copper nanoparticles (2%) as additives) is used. The enclosure is heated from one side and opposite side is isothermal at 300 K, and remaining walls are thermally insulated. Melting heat transfer in a rectangular enclosure with different orientations are investigated numerically. The flow field results in nonuniform melting of the composite phase change material (CPCM). The interface morphology is used to infer flow structure and the extent of two-dimensional energy transport. These flow patterns are found to be dependent on the orientation and the initial CPCM sub-cooling. The results reveal that the enclosure orientation has a significant effect on the formation of natural convection currents and consequently on the heat transfer rate and melting time of the CPCM. As the orientation changed from deep to shallow, the convection currents in the enclosure, increases and chaotic flow structure appear. Hence, it can be concluded that the heat transfer enhancement ratio for the deep enclosure is more than that of the shallow enclosure. � Published under licence by IOP Publishing Ltd.