A numerical study has been developed to analyze the wall conduction effect on natural convection heat transfer in a two dimensional vertical enclosure filled with phase change material (PCM) undergoing a melting process. One vertical wall of the enclosure is kept isothermally at a temperature higher than that of the phase change temperature while the other walls are kept insulated. A mathematical model has been developed based on the coupling of the equations that govern the phenomenon. The finite element method is used to develop this model to solve the transient behavior of melting phenomenon. Body-fitted curvilinear coordinates are used for treating the moving boundary (melting front). The effects of void fraction, i.e. wall thickness, wall and PCM thermophysical properties and Rayleigh number on the heat transfer characteristics and melting rate are investigated.
Results obtained from this model have been verified through a comparison with those available in the existing publications. A new correlation equation for the average Nusselt number based on the total heat input with the melting rate, void fraction, wall and PCM thermophysical properties and operating conditions is derived. Other different correlation equations for the average Nusselt number at the wall-liquid phase interface and the melting rate based on the numerical results are also presented. |
