Enhanced thermal and flow behavior of Cu-Al2O3/water hybrid nanofluids in porous media under variable magnetic field conditions

This study investigates the flow characteristics and heat transfer behavior of a copper-alumina hybrid nanofluid suspended in water over a porous exponentially stretching surface. The analysis incorporates the effects of temperature-dependent viscosity, viscous dissipation, and a spatially varying magnetic field to provide a comprehensive understanding of fluid motion and thermal performance under complex physical conditions. The governing equations for momentum and energy are formulated under steady, incompressible, and laminar flow assumptions and are transformed into ordinary differential equations using similarity transformations. These equations are then solved using the shooting method combined with the Runge-Kutta-Fehlberg algorithm to ensure computational accuracy. The study systematically examines the influence of key parameters, including nanoparticle volume fraction, magnetic field strength, permeability of the porous medium, and viscous dissipation, on velocity and temperature distributions within the boundary layer. The results demonstrate that temperature-dependent viscosity plays a crucial role in fluid dynamics, as increasing temperature reduces viscosity and enhances fluid motion. Additionally, the presence of viscous dissipation leads to internal heat generation, significantly raising the fluid temperature near the boundary layer. The findings highlight the superior thermal conductivity of hybrid nanofluids compared to conventional working fluids, making them highly effective for applications requiring efficient heat dissipation. These insights are particularly relevant to industries such as heat exchangers, cooling systems, polymer extrusion, and advanced thermal management solutions. By elucidating the intricate interaction between flow behavior and heat transfer in porous media, this study provides valuable guidance for optimizing hybrid nanofluids in practical engineering and industrial applications.