Magnetoconvection driven melting of nanoenriched paraffin wax in cubical enclosure. (July 2023) - Harish, R.
Abstract: The latent heat thermal energy storage using phase change material plays a vital role in thermal power production, solar energy storage and nuclear reactors. The dispersion of metallic nanoparticles into phase change material in the presence of magnetic field controls the natural convection induced melting process. This paper numerically investigates the thermo-magnetic turbulent convection induced melting of nanoenriched paraffin wax dispersed with hybrid magnetic nanoparticle pairs in a cubical enclosure with hot bottom wall. The magneto free convection effect on the melting process is investigated for high value of Hartmann number and Rayleigh number. The melting characteristics is modeled using enthalpy-porosity formulation discretized using finite difference technique and the computations are performed using an in-house three-dimensional code. It is found that the natural convection induced melting generates quadruplet thermal plume patterns from the melt zone. The dispersion of hybrid nanoparticle pairs of ferrous ferric oxide and multi-wall carbon nanotubes for particle volume fraction of 4% enhanced the melting fraction and average Nusselt number of paraffin wax by 75.21% and 42.16% respectively. The high Lorentz force developed for turbulent Hartmann number of 2000 diminished the convection induced melting phenomena. The melting time and melting rate of nanoenriched paraffin wax are a decreasing function of Hartmann number and it decreased the melt pool velocity and kinetic energy by 73.5% and 71.42%. The increase in Hartmann number decreased the average Nusselt number of nanoenhanced paraffin wax by 20.88%. Graphical abstract: Highlights: Thermomagnetic convection induced melting of NEPCM is investigated. Quadruplet thermal plume patterns are developed in the melt zone. The high Lorentz force diminished the melting rate. Heat transfer is enhanced by 42.16% using hybrid magnetic nanoparticles. Magnetic field reduced the Nusselt number by 20.88%.