<p>This study presents a numerical investigation of magnetohydrodynamic forced convection and entropy generation in a uniformly heated horizontal tube filled with porous media, using binary (Al₂O₃–TiO₂/Water-EG) and ternary (Al₂O₃–TiO₂–CNT/Water-EG) hybrid nano-fluids. The flow and thermal fields are modeled using the finite volume method with single-phase and thermal-equilibrium assumptions. The analysis is conducted for a Reynolds number of 750, nanoparticle volume concentration of 6%, Darcy numbers ranging from 10⁻⁴ to 10⁻¹, and Hartmann numbers between 10 and 40, under two magnetic field orientations (0° and 90°). The results demonstrate that reducing the Darcy number significantly enhances heat transfer, with the binary hybrid nano-fluid achieving up to a 105.36% improvement. Additionally, applying the magnetic field parallel to the flow (0°) leads to further enhancement, particularly for the ternary hybrid nano-fluid. In contrast, when the magnetic field is perpendicular (90°), its influence on thermal performance is negligible. This study highlights the synergistic effects of nanoparticle composition, magnetic field orientation, and porous media structure, offering new insights into optimizing nano-fluid-based thermal systems for enhanced energy efficiency.</p>