Two-Dimensionalnumerical Study of the Effect of Nanoparticles on the Fusion and Freezing Process of Phase Change Materials Using a Computing Method

Abstract

In this paper, a scalar two-dimensional analysis was conducted on the influence of nanoparticles on the thawing and freezing rate of phase-change materials based on enthalpy method that is an innovative calculation method. To this end, carbon nanotubes (CNTs) and aluminum oxide nanoparticles (NPs) were employed as a model of cylindrical and spherical nanoparticles, respectively.Paraffin and a composite of hydrated salts was also utilized as the PCM. The numerical procedure involved the simulation of the phase change process based on finite difference using enthalpy approach. Because of the recent innovations in computer calculation and also its connection with mechanical engineering a computational code was written for this purpose.Simulation results indicated a reduction in time of thawing and freezing upon incorporation of nanoparticles into the phase change material. For both states, CNTs showed the better result due to acceleration of the heat transfer. The biggest increase (28%) in the rate of thawing and freezing was for CNT-paraffin system; while the lowest increase (6%) was observed in aluminum oxide-hydrated salt system. This result can be utilized to control the speed of energy storage and release.