Unsteady melting and solidification of a nano-encapsulated phase change materials hybrid nanofluid in an eccentric porous annulus

A detailed knowledge of the melting and solidification of a suspension of Nano-Encapsulated Phase Change Materials (NEPCM) is essential to analyze the thermal behavior of the PCM materials. This study investigates the convective heat analysis of NEPCM suspensions during the solidification and melting process in a porous domain. The inner cylinder of the eccentric annulus is used as a thermally active wall for charging and discharging the suspension while an adiabatic condition is used at the outer wall of the cylinder. The thermal behavior of the suspension comprising nano-encapsulated PCM is analyzed throughout the melting and solidification process. The PCM core fusion temperature and eccentricity of the annulus affect the thermal performance. The overall heat transmission decreases when the PCM core fusion heat approaches to the suspension temperature. An increase in thermal convection between the nanofluid and porous matrix reduces the Nusselt number in the liquid but increases the heat transmission in the porous foam. An increase in Stefan number enhances the heat transfer in the enclosure.