Enhancement of Heat Transfer and Entropy Characteristics in Ag–MgO/Water Hybrid Nanofluid under Thermo-Magnetic Convection

Convection from the environment and energy generation in porous envelopes are significant for the thermal productivity of tiny heat transfer devices and solar thermal systems. Hybrid nanofluids have better heat transfer than regular fluids. The goal of this study is to quantitatively explore the effects of fluid layer placement on entropy formation and convection heat transfer in nature in a triangle-shaped partitioned chamber filled with a silver magnesium oxide/water hybrid nanofluid layer. The dimensionless governing formulae for laminar and incompressible flow are obtained using the finite component technique. Key parameters examined are the Darcy number (ranging from ten to the power of minus five to ten to the power of minus two), the location of the porous layer (bottom, side, or top region of the triangular partition), and the Rayleigh number (from ten to the power of four to ten to the power of six). The results show that placing the porous layer in the side region increases the average Nusselt number by up to 22% compared to a non-porous configuration, while bottom placement yields a 12% increase. Total entropy generation is reduced by eighteen percent when the porous medium occupies the side region at a Darcy number of ten to the power of minus three. Increasing the Rayleigh number from ten to the power of four to ten to the power of six doubles the thermal entropy generation but reduces the frictional entropy contribution by forty percent. The side porous form has the highest Bejan number, indicating that entropy growth is driven by irreversible heat transmission. The location of the porous media is an important control element for maximizing both heat transmission and thermal efficiency in natural convection flows. The side placement provides the best balance between enhanced Nusselt number and minimized entropy generation. These findings are relevant to advanced thermal management systems, including heat exchangers, solar thermal collectors, HVAC and refrigeration units, thermal energy storage devices, biomedical cooling technologies, nanofluid-based industrial processes, and waste heat recovery systems.