Forced-convection heat transfer of ferrofluids in a circular duct partially filled with porous medium in the presence of magnetic field

In this article, effects of magnetic fields induced by a finite length solenoid on the forced-convection heat transfer in a pipe partially filled with porous medium have been investigated. In this regard, two-dimensional steady-state fluid flow in the pipe was considered and the Darcy-Brinkman equation of motion was applied to model the fluid flow in the porous medium, as well as the thermal equilibrium was assumed between the solid phase and the magnetic nanofluid. Effects of electric current passing through the solenoid and the solenoid dimensions (i.e.; diameter and length) on the forced-convection heat transfer were studied carefully. The combined effects of the magnetic field and the porous medium lead to a higher mixing intensity and disruption of the thermal boundary layer which in turn result in the enhancement of the local Nusselt number value at the expense of low-pressure drop increase due to partially filling the pipe. In the simulation study, variations of the magnetic field in different media were taken into account and the assumption of the linear function of magnetization with respect to the applied magnetic field intensity was relaxed. The obtained simulation results indicate that under the influence of the magnetic field induced by a solenoid with a current intensity of 10 A, the average Nusselt number value increases up to 30%.