Experimental study of thermal convection and melting dynamics in a Phase Change Material (PCM) embedded in a solid foam
Year: 2025
Type: article
Abstract: We investigate the role of thermal convection in the melting of a Phase Change Material (PCM) embedded in a highly porous plastic foam . Using Magnetic Resonance Imaging (MRI), we examine the melting of the composite PCM system heated from below and cooled from above. Our results show that, under convective conditions, the melting interface develops a wavy surface shaped by thermo-convective flows. Convection significantly enhances the melting rate, and can lead to final liquid heights more than twice those observed in the conductive regime, depending on the imposed temperature boundary conditions at the top and bottom surfaces. Flow field analysis reveals different convection patterns, from cross-rolls to hexagonal and square convective cells , with local velocity fields strongly influenced by the porous medium geometry. Finally, heat transfer analysis shows a not-clear relation between Nusselt number ( N u ) and porous medium Rayleigh number ( R a ∗ ) for R a ∗ > R a c ∗ , where R a c ∗ is the critical Rayleigh number for convection. However, when N u is normalized by the temperature difference ratio ( Θ ) and plotted as a function of R a ∗ and the phase change ratio A (the average height of the solid PCM relative to that of the liquid PCM), a good data collapse is achieved, leading to the scaling N u / Θ ∼ ( R a ∗ / A ) 0 . 5 . These findings provide a basis for further experimental and numerical studies on heat and mass transfer in more complex composite systems .
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,220
OpenAlex ID: W4411133261