Mixed convection heat transfer and entropy generation of MHD hybrid nanofluid in a cubic porous cavity with wavy wall and rotating cylinders

The current simulations are for the three-dimensional (3D) Fe₃O₄/MWCNT-water hybrid nanofluid flow within a 3D cubic enclosure filled with a porous medium. It was assumed that the flow area contains two rotating cylinders and has an upper wavy wall. Also the magnetic field is also applied to the problem due to magnetic nanoparticles in the base water. The Galerkin finite element method (GFEM) with a triangular element shape was applied to solve the governing equations. The findings were shown for a range of flow parameters such as angular speed of the cylinder (Ω=-500–1000), Hartmann number (Ha = 0–10), Darcy number (Da = 10⁻⁵–10⁻²), and direction of cylinders rotations and their positions in the cavity. The influence of the various parameters on flow, thermal transport, and entropy production is illustrated by the stream function, isotherms, and isentropic contours. Higher values of Ω Da and lower values of Ha enhanced the heat transfer and Nusselt number. Entropy production is mostly due to heat transfer; however, fluid-friction and magneto effects also contribute.