Thermal dynamics and magnetohydrodynamics in ferrofluidic wall jet flow: Entropy generation in heat and mass transfer

• Ferro-nanoparticles have unique magnetic properties for the precise control of fluid flow using external magnetic fields. • Wall jet ferro-hybrid nanofluids with entropy generation are analyzed under external magnetic fields. • The Runge-Kutta algorithm is used for solving ordinary differential equations. • Increasing thermophoretic parameters and Brown motion lead to the decay of the entropy generation. • Ferro-hybrid nanofluids can enhance the heat and mass transfer but no effects on velocities and entropy generation. Wall jet nanofluids with entropy generation possess several applications in cooling electronic devices, and solar collectors. The unique magnetic properties of the ferro-nanoparticles allow for the precise control of fluid flow using external magnetic fields, which is invaluable for targeted cooling or heating. In this study, we investigate wall jet hybrid nanofluid materials with ferrous-ferric oxide and copper oxide in conventional fluid water. The governing velocity, mass, and heat transfer equations are calculated to a set of ordinary differential equations (ODEs) via similarity parameters that are solved numerically. Effects of physical parameters, including thermophoretic parameters, Brownian motion parameters, and magnetic parameters, on velocities, temperature and entropy generations are analyzed using graphical representations. The results show that rising the Brownian motion, the magnetic term, or the thermophoresis term rises the fluid temperature. Furthermore, Brownian motion, or the thermophoresis effect increases temperature more for the ferro-hybrid nanofluids than that for single nanofluid. Increasing the thermophoretic parameters and Brown motion lead to the decay of the entropy generation due to enhanced thermal gradients and particle movement. However, the entropy generation enhances as the thermal radiation term rises. This demonstrates that the hybrid nanofluids can raise the thermal and mass transfer but no effects on velocities and entropy generation, compared to the single nanofluid.