Convective heat transfer in a square cavity filled with nanofluids under the influence of periodic magnetic field

Abstract

Unsteady natural convection flow and heat transfer utilizing magnetic nanoparticles in the presence of a periodic magnetic field inside a square cavity are simulated numerically. The magnetic field is applied as a sinusoidal function of the y coordinate. Nanofluids are isothermally heated and cooled by the left and right side walls at uniform temperatures of Th and Tc respectively while the top and bottom walls are insulated. The Galerkin weighted residual based finite element method has been employed to solve the governing partial differential equations after converting them into a non-dimensional form using a suitable transformation of variables. Comparison with previously published work is shown and excellent agreement is obtained. The effects of various model parameters such as Rayleigh number, Hartmann number, period of magnetic field, and dimensionless time on isotherms have been displayed graphically in the form of isotherms. They are also discussed from the physical and engineering points of views. Average Nusselt number on the left heated wall for different Hartmann number and Rayleigh number with different periods of magnetic field are investigated. The average heat transfer rate for 9 types of nanofluids has also been found out on the left heated wall. Finally, it is observed that the average heat transfer of Fe3O4-H2O nanofluid is much higher than other 8 types of nanofluids.