Magnetohydrodynamic convective heat transfer of a hybrid nanofluid over a circular cylinder in a non-Darcy porous medium using the Keller Box method

This study investigates the magnetohydrodynamic (MHD) boundary-layer flow and heat transfer characteristics of a water-based hybrid nanofluid containing copper oxide and silver nanoparticles over a circular cylinder embedded in a non-Darcy porous medium. The mathematical model incorporates the combined effects of a transverse magnetic field, thermal radiation, non-uniform internal heat generation or absorption, and porous medium resistance. The non-Darcy formulation considers both viscous and inertial resistance effects, making the model suitable for moderate flow regimes encountered in practical thermal systems. By employing suitable similarity transformations, the governing nonlinear partial differential equations are transformed into a coupled system of nonlinear ordinary differential equations and solved numerically using the Keller Box method due to its stability and computational accuracy for boundary-layer problems. The results reveal that increasing the magnetic parameter significantly suppresses the velocity distribution because of the Lorentz force effect, whereas thermal radiation and heat generation parameters enhance the temperature field and improve thermal transport characteristics. Furthermore, higher nanoparticle volume fractions considerably increase the heat transfer rate owing to enhanced thermal conductivity of the hybrid nanofluid. The present study also demonstrates the combined influence of porous medium properties and inertial resistance on skin friction and thermal boundary-layer development. The novelty of this work lies in the simultaneous consideration of MHD effects, thermal radiation, non-uniform heat source/sink, and non-Darcy porous medium characteristics in hybrid nanofluid flow over a circular cylinder using the Keller Box technique. The findings of this study contribute to a better understanding of advanced thermal transport mechanisms and may be useful in engineering applications such as cooling systems, thermal energy devices, nuclear reactors, electronic equipment cooling, and porous heat exchangers.