The effect of combining magnetic field and high-conductivity nanoparticles on the fusion rate of a phase change material

In phase-change materials (PCMs) application for cooling, melting happens at nearly constant temperature preventing an increase in temperature until full melting occurs. So, controlling the fusion duration can be helpful to maintain the thermal comfort at lower energy demand. This study investigates the impact of using a uniform magnetic field on the rate of melting of Octadecane PCM, with and without the addition of high-conductivity nanoparticles, and when considering enclosures of various aspect ratios. We note that about 43% decrease in liquid fraction, and consequently melting rate, can be obtained for a Hartmann number of 100 and when Lorentz force direction is opposite to the buoyant force. We also show that the aspect ratio of the enclosure has an impact on the magnetic susceptibility of the PCM. Also, with the addition of nanoparticles, the effect of Lorentz force becomes more intense but the overall decrease in melting rate is not evident because of the increase in conductive heat transfer. So, their use might be promising in scenarios where increasing the rate of melting is needed. Consequently, for a substantial impact on the fusion rate of a phase-change material, the strength of the magnetic field, the enclosure shape, and the conductivity of the material should be carefully considered.