Turbulent magnetohydrodynamic natural convection in a heat pipe-assisted cavity using disk-shaped magnesium ferrite nanoparticles

Abstract

The prospect of altering the thermophysical properties of ferrofluid with an influence of magnetic field leads to improving natural convection in various heat transfer systems. This investigation principally focuses on the studies of electromagnetism-based turbulent natural convection heat transfer of low-density disk-shaped magnesium ferrite/water-based ferrofluid, filled in a novel heat pipe-assisted cubical cavity at various volume fractions. Two flat plate heat pipes were used to maintain temperature differences in the cavity. To advance the buoyancy of the working fluid inside the cavity, deliberately low-density ferrofluid containing disk-shaped particles was formulated using the hydrothermal method. The temperature difference between the two heat pipe-assisted vertical walls was sustained with four distinct temperature ranges from 10 to 25 °C. The ferrofluid filled in the cavity was then subjected to magnetic field ranging from 0 to 350 G to understand the thermomagnetic convection effects on heat transfer. The optimal volume fraction of ferrofluid for maximum heat transfer was found to be 0.05% at a wall temperature difference of 25 °C, owing to 23.51% improvement in average heat transfer coefficient along with 33.37% improvement in average Nusselt number when compared to water. With the application of a magnetic field of 350 G, the average heat transfer coefficient was further enhanced by 10.11%, and the average Nusselt number improved by 6.28% for 0.05% volume fraction in comparison to the condition where no magnetic field was applied.