Melting transport enhancement of nanoparticle-enhanced latent heat thermal energy storage system under influence of non-uniform magnetic field induced by two variable sources

Thermal performance enhancement of convective transport in latent heat thermal energy storage system using the magnetic field as a flow regulator is in research trend. The hydrothermal characteristics of nanoparticle-enhanced phase change material in a square enclosure in the presence of non-uniform magnetic fields are investigated in the present study. The effects of pertinent parameters, magnetic strength ratio, magnetic number, Rayleigh number, and particle volume fraction are analyzed on the phase interface propagation, streamline contours, average melt volume fraction, and average Nusselt number on the hot wall. A numerical code based on the finite volume method is developed to discretize and solve the governing equations in the enthalpy-porosity approach, along with source terms associated with the momentum and energy equations. The results show that the non-uniform magnetic field exhibits a strong impact on convective thermal transport and can be an effective phase change enhancement technique. The magnetic strength ratio has a dominant influence on the melting rate than the magnetic number and particle volume fraction. A change in magnetic strength ratio, magnetic number, and particle volume fraction by 2, 2000, and 2% from the base condition reduces the total melting time by 4.45%, 3.37%, and 2.5%, respectively. Further, the melting rate is enhanced by 16.67% with the combined increment in magnetic strength ratio and magnetic number by 2 and 2000, respectively. Moreover, the influence of the magnetic field on the NPCM becomes more apparent relatively at low Rayleigh number.