Two-phase mixture model simulation of the hydro-thermal behavior of an electrical conductive ferrofluid in the presence of magnetic fields

This paper presents a numerical investigation of the hydro-thermal behavior of a ferrofluid (sea water and 4 vol% Fe3O4) in a rectangular vertical duct in the presence of different magnetic fields, using two-phase mixture model and control volume technique. Considering the electrical conductivity of the ferrofluid, in addition to the ferrohydrodynamics principles, the magnetohydrodynamics principles have also been taken into account. Three cases for magnetic field have been considered to study mixed convection of the ferrofluid: non-uniform axial field (negative and positive gradient), uniform transverse field and another case when both fields are applied simultaneously. The results indicate that negative gradient axial field and uniform transverse field act similarly and enhance both the Nusselt number and the friction factor, while positive gradient axial field decreases them. It is also concluded that, under the influence of both fields by increasing the intensity of uniform transverse field the effect of non-uniform axial fields decrease.

▸ In addition to the FHD principles the MHD principles have also been taken into account. ▸ The mixed convective hydrodynamic and heat transfer have been investigated. ▸ Negative gradient axial and uniform transverse field enhance Nusselt number and friction factor. ▸ Positive gradient axial field decreases Nusselt number and friction factor. ▸ Increase in intensity of transverse fields decreases the effects of non-uniform axial fields.