Enhanced Heat Transfer in Magnetohydrodynamic Hybrid Nanofluids on a Stretching Surface: A Cattaneo-Christov Thermo-Fluid Model with Thermal Radiation

This study explores the thermal performance of a water-based hybrid nanofluid, propelled by a stretching sheet and subjected to a transverse magnetic field. The hybrid nanoparticles are designed to enhance realizable heat transfer in thin liquid streams, with attention to realistic thermo-physical behavior. The energy transport is modeled using the Cattaneo–Christov constitutive relation to account for finite-speed heat propagation, along with thermal radiation and viscous dissipation effects. Constant fluid properties are considered for tractability, and the governing equations are derived from the conservation laws for momentum and energy. Through a similarity transformation, the partial differential equations are reduced to a system of nonlinear ordinary differential equations (ODE), which are solved numerically using a high-order Runge–Kutta–Fehlberg scheme. Comprehensive validation and sensitivity analyses are performed to establish the influence of key nondimensional groups, including the magnetic parameter, radiation parameter, relaxation time (Cattaneo–Christov), nanoparticle volume fraction, and stretching parameter, on velocity, temperature, and heat flux profiles. Results reveal quantitative enhancements in surface heat transfer rates and notable shifts in temperature distribution with increasing magnetic intensity and nanoparticle loading, moderated by thermal relaxation effects. The radiative parameter had an important effect on the thermal properties for both mono and hybrid nanofluids. There is good agreement between the current results and the previously reported data, according to a comparison analysis. The results of this study have important implications for a number of engineering, industrial, and pharmacological applications, such as wastewater treatment procedures, biofilm formation, and geothermal energy extraction.