Finite element analysis of morphological effects and nanolayer thermal conductivity in Boger nanofluids under thermal radiation

This study focuses on the two-dimensional magnetohydrodynamic Darcy–Forchheimer flow of a Boger nanofluid over a stretching sheet, incorporating multiple enhancements in the diameter-based viscosity and thermal conductivity models. The heat transfer analysis considers the effects of thermal radiation, viscous dissipation, and Joule heating. To account for nanoparticle geometry, non-spherical thermal conductivity and diameter-based viscosity models are applied based on various shapes and size factor of copper nanoparticles. The influence of metallic nanoparticle morphology on heat transfer performance is analyzed through nanofluid flow simulations. The governing nonlinear partial differential equations are converted into dimensionless form using appropriate similarity variables, with the pressure term eliminated via the penalty method. The resulting dimensionless equations are solved using the finite element method (FEM), and all simulations are performed in MATLAB. The impact of various parameters on the velocity and temperature profiles reveals distinct behaviors across the three viscosity and thermal conductivity models. An increase in the solvent fraction parameter enhances the velocity profile, with the third diameter-based viscosity model demonstrating optimal flow behavior at smaller nanoparticle diameters. Conversely, higher Forchheimer numbers suppress the velocity profile, with the second diameter-based viscosity model showing the most significant reduction at larger diameter values. Larger copper nanoparticle diameters and higher shape factors enhance heat transfer in the temperature profile for the non-spherical thermal conductivity model, with platelet-shaped nanoparticles exhibiting the best thermal performance.