Thermodynamic irreversibility in magnetized double-diffusive ternary hybrid nanofluid convection with thermal radiation and heat sinks in a porous circular chamber

Purpose – This study aims to investigate entropy generation and transport characteristics of magnetohydrodynamic double-diffusive natural convection in a porous convex circular enclosure filled with an Al₂O₃–CuO–Ag/water ternary hybrid nanofluid, with emphasis on the combined effects of buoyancy, magnetic field, permeability, radiation and nanoparticle loading. Design/methodology/approach – A mathematical model based on the Boussinesq approximation is formulated and transformed into dimensionless form. The governing equations are solved numerically using a Galerkin finite element method. The computational model is validated through grid independence and benchmark comparisons. Findings – The results reveal that increasing the Rayleigh number (Ra) significantly enhances buoyancy-driven convection, leading to more than a 300% increase in kinetic energy and approximately 140% enhancement in Sherwood number. Increasing the Darcy number (Da) improves permeability and raises viscous and total entropy generation by about 85%–90%. In contrast, increasing the Hartmann number (Ha) introduces Lorentz-force-induced magnetic damping, reducing viscous and total entropy by approximately 55%–60% and 23%, respectively, despite a significant increase in magnetic entropy. Furthermore, higher buoyancy ratio, radiation parameter and Lewis number intensify entropy generation, whereas increasing nanoparticle concentration suppresses flow intensity and reduces overall entropy generation. Originality/value – This study provides a comprehensive analysis of thermosolutal convection incorporating magnetohydrodynamic effects, porous resistance, radiation and ternary hybrid nanofluid interactions within a circular finned enclosure. It offers new insights into entropy generation mechanisms and the competing roles of buoyancy, magnetic damping and diffusive transport, which are not fully explored in existing studies.