Enhanced Thermal Efficiency Using Hybrid Nanofluids in MHD Boundary Layer Flow: Buoyancy and Entropy Perspective

The growing relevance of hybrid nanofluids (HNFs) in advanced thermal management systems has driven extensive research in recent years. Nevertheless, the cumulative effects of thermal and solutal buoyancy, MHD, viscous dissipation, and Newtonian heating/cooling on HNF transport remains unaddressed. Motivated by their significance in solar energy systems, electronic cooling, and chemical reactors, this study presents a comprehensive numerical investigation of magnetohydrodynamic (MHD) hybrid nanofluid flow over a porous stretching sheet, incorporating the combined effects of thermal and solutal buoyancy forces, Newtonian heating/cooling, viscous dissipation, and heat generation/absorption. The hybrid nanofluid (Cu/Al2O3-water) is modelled using the Tiwari–Das approach. The governing PDEs are transformed into ODEs through similarity transformations and solved using a finite-difference-based Runge–Kutta–Fehlberg method in MATLAB. The analysis reveals that both thermal and solutal buoyancy significantly enhance fluid temperature while reducing nanoparticle concentration through stronger convective transport. The skin-friction coefficient enhances with the copper nanoparticle volume fraction but decreases with solutal buoyancy. The hybrid nanofluid demonstrates superior heat-transfer performance, with up to a 16% higher Nusselt number compared to single nanofluids, making it ideal for thermal regulation in microchannel heat sinks and renewable energy systems. Validation against prior literature confirms the model’s accuracy.