Numerical simulation and experimental verification of constrained melting of phase change material in inclined rectangular enclosures

In the present study, melting of phase change material (PCM) in vertical and inclined rectangular enclosures is numerically investigated. Comparison of the numerical and experimental results reveals that the two-dimensional numerical simulations of PCM melting in vertical enclosures can accurately predict both the liquid fraction and the temporal evolution of the solid-liquid interface. Also, it well predicts the instantaneous values of liquid fractions for inclined enclosures (45 degrees and 0 degrees) with a maximum deviation less than 6.5%. Regardless of the Stephan number, the complete melting time in 0 degrees and 45 degrees inclined enclosures are respectively about 52% and 37% shorter as compared to the vertical enclosure. Heat transfer enhancement and consequently melting rate augmentation in inclined enclosures are found to be the result of the intensification of natural convection flows and formation of thermal plumes originating from counter-rotating vortices. Moreover, to generalize the results, a group of dimensionless numbers is introduced and used to develop three new correlations for prediction of the instantaneous liquid fraction, energy storage and time-averaged Nusselt number in inclined enclosures.