Irreversibility Minimization and Heat Transfer Enhancement in MHD Mixed Convection of Hybrid Nanofluid within a Porous Cavity

This study numerically investigates magnetohydrodynamic mixed convection heat transfer of a Cu–GO/blood hybrid nanofluid confined within a differentially heated square cavity under a uniform transverse magnetic field. The analysis addresses the combined influence of magnetic field intensity, internal heat generation or absorption, and hybrid nanoparticle dispersion in a blood-based fluid, a configuration relevant to biomedical and microscale thermal management systems. The vertical cavity walls are maintained at constant but unequal temperatures, while the horizontal walls are thermally insulated. Blood is modeled as the base fluid with uniformly dispersed copper and graphene oxide nanoparticles to enhance thermal transport. The governing incompressible Navier–Stokes and energy equations, formulated using the Boussinesq approximation, are solved numerically to examine the effects of Reynolds number, Richardson number, Hartmann number, nanoparticle volume fraction, and heat source or sink strength. The results reveal that increasing magnetic field intensity significantly suppresses convective circulation and reduces the average Nusselt number due to Lorentz force damping, whereas higher hybrid nanoparticle concentrations enhance heat transfer through improved effective thermal conductivity. The interaction between buoyancy and imposed flow is shown to be strongly influenced by magnetic field strength and internal heat generation or absorption. These findings provide useful insight into magnetic control of mixed convection heat transfer in blood-based hybrid nanofluids and support the design of advanced biomedical thermal regulation and microscale heat transfer applications.