Joule heating effects on electromagnetic rotating flow of CuO-TiO2-EG and Water nano liquid over an exponentially stretching surface

Abstract

This study investigates the heat transfer and flow characteristics of a 50%-50% ethylene glycol-water-based hybrid nanofluid, augmented with  (copper oxide) and  (titanium dioxide) nanoparticles, over a rotating, exponentially stretching surface under MHD and convective boundary conditions. Using Maple, the governing equations are solved to analyze the effects of magnetic parameter (M), stretching ratio (α), rotation parameter (γ), nanoparticle volume fraction (ϕ), temperature exponent (A), and Eckert number (Ec). Results show that increasing α reduces primary flow velocity, enhances transverse velocity, and thins the thermal boundary layer. Rotation (γ) diminishes both velocity components via Coriolis effects, while a higher M reduces velocities due to Lorentz force, elevating temperatures and thermal boundary layer thickness. Increasing ϕ lowers velocities due to higher viscosity but enhances thermal conductivity, raising temperatures. A higher A reduces temperatures, thinning the thermal boundary layer, whereas elevated Ec increases temperatures via viscous dissipation. The magnetic field reduces the Nusselt number but increases skin-friction coefficients. CuO-based nanofluids exhibit greater magnetic sensitivity than TiO₂-based ones due to higher electrical conductivity. Hybrid nanofluids outperform conventional nanofluids in heat transfer under magnetic influence, with nanoparticle composition being critical. These findings inform applications in polymer extrusion, rotating machinery cooling, electromagnetic pumps, MHD power generation, fiber-spinning, and microchannel thermal systems, offering insights for optimizing fluid dynamics and thermal efficiency.