Optimizing magnetic-natural convection using anisotropic porous media: A local thermal non-equilibrium approach

Purpose: Applying external magnetic fields and employing porous media are both common approaches to control the heat transfer characteristics of magnetic fluids. To optimize such control strategies, the present study proposes the use of anisotropic media with structured design in the heat transfer domain and assesses its impact. In particular, the natural convection of a magnetic fluid through an anisotropic porous medium under a non-uniform magnetic field is investigated. Design/methodology/approach: In order to model the phenomena at play, the governing partial differential equations including mass, momentum, and conservation laws for the anisotropic porous medium taking into account the use of local thermal non-equilibrium approach are developed and solved employing the finite volume technique. Findings: Different combinations of parameters related to fluid motion and energy transfer performance, like the thermal conductivity ratio, interface heat transfer coefficient, permeability ratio and orientation angle for the permeability tensor within the anisotropic porous cavity, are evaluated. The results indicate that the most important factors to manage heat transfer and flow structures are changes of thermal conductivity ratio and interface heat transfer coefficient. The influence of permeability tensor is found to be essential for flow structures, but its influence on heat transfer rates remains weak.