Thermodynamic optimization of pulsatile Cu–GO/water hybrid nanofluid flow in a magnetized porous cavity

The enhancement of thermal performance with minimal thermodynamic irreversibility is a key requirement in the design of modern energy and thermal management systems, particularly those involving magnetized porous enclosures. The present study aims to numerically investigate entropy generation and thermodynamic optimization in a forced convection flow of a Cu–GO/water hybrid nanofluid confined within a square porous cavity subjected to a transverse magnetic field. The hybrid nanofluid behaviour is modeled using the Tiwari–Das formulation, while the porous medium is characterized by the Darcy–Brinkman–Forchheimer model. The cavity consists of stationary horizontal walls with centrally heated sections maintained at a constant high temperature, whereas the vertical walls are kept cold. The governing equations are solved numerically to analyze the effects of the Hartmann number, Darcy number, and nanoparticle volume fraction on heat transfer characteristics and entropy generation. The results reveal that the inclusion of graphene oxide nanoparticles significantly enhances heat transfer performance while suppressing entropy generation under appropriate magnetic field strengths and porous resistance conditions. The study concludes that Cu–GO hybrid nanofluids provide an effective thermodynamic optimization strategy for magnetohydrodynamic convection in porous cavity-based thermal systems.