Hydrothermal behavior and entropy analysis of MHD hybrid nanofluid flow driven by buoyancy within cloverleaf enclosure

Purpose Minimizing entropy generation and understanding buoyancy-driven heat transfer mechanisms in complex enclosures are essential for improving the efficiency of advanced thermal management systems. While natural convection of nanofluids in simple cavities has been widely studied, the combined effects of complex enclosure geometry, fin configuration, magnetic field and entropy generation in hybrid nanofluids remain insufficiently explored. This study aims to investigate magnetohydrodynamic (MHD) natural convection and entropy generation of an Ag–MgO/water hybrid nanofluid in a finned cloverleaf-shaped enclosure. Design/methodology/approach The governing equations for mass, momentum and energy are transformed into dimensionless form and solved using a Galerkin-based finite element method. Grid independence verification is performed to ensure numerical accuracy. The influences of Rayleigh number (104 = Ra = 106), Hartmann number (0 = Ha = 80), nanoparticle volume fraction (0.00 = ϕ2 = 0.015), Darcy number (10−4 = Da = 10−2) and fin length on flow behavior, heat transfer and entropy generation are systematically analyzed. Findings Increasing the Rayleigh number enhances buoyancy-driven convection, leading to a 32.8% increase in the average Nusselt number. In contrast, increasing the Hartmann number suppresses fluid motion and reduces heat transfer by 14.7% due to magnetic damping. Higher nanoparticle concentration increases entropy generation because of elevated viscous resistance. Longer fins reduce total entropy generation by weakening circulation intensity, whereas shorter fins and lower porous resistance enhance convective heat transfer. Practical implications The results provide design insights for improving thermal management systems involving hybrid nanofluids in applications such as electronic cooling, energy storage devices and porous heat exchangers. Originality/value This study presents a novel analysis of MHD natural convection and entropy generation in a finned cloverleaf-shaped enclosure filled with Ag–MgO/water hybrid nanofluid, highlighting the combined influence of geometry, porous resistance, magnetic field and fin configuration on heat transfer and thermodynamic irreversibility.