Convective flow analysis for moderate Rayleigh numbers of nano encapsulated phase change materials-water filled enclosure with various thermal conditions

The numerical study of free convection heat transfer inside a square enclosure having exponential and sinusoidal thermal profiles filled with hybrid nanofluid is reported. The hybrid nanofluid is nano-encapsulated phase change materials (NEPCMs) and water (H2O). The NEPCMs are constructed by a polyurethane as a shell and an n-nonadecane as a core. The n-nonadecane undergoes a phase transition and capable of storing or releasing a large quantity of latent heat. The study focuses on the effect of heating exponent and heating frequency to the convective flow and melting distribution. A Galerkin finite element method is applied to solve the governing equations. The result from the present model is compared with the previously published articles. The controlling parameters under consideration are the heating exponent, 0 <= angstrom <= 2, the heating frequency, 1 <= N <= 4, the Rayleigh number, 104 <= Ra <= 106. It is found that the lowest exponent and frequency of heating gives the best thermal performance.