Analysis of Coupled Thermal and Concentration Gradients in Nanofluid Boundary-Layer Flow over a Stretching Surface

This study presents an analysis of coupled thermal and concentration gradients in nanofluid boundary-layer flow over a stretching surface under the influence of magnetic, thermal, and mass transport effects. The governing nonlinear partial differential equations describing momentum, energy, and nanoparticle concentration are formulated for an electrically conducting nanofluid and solved numerically using the finite element method. Emphasis is placed on the roles of key dimensionless parameters including the magnetic field parameter, thermal and solutal Grashof numbers, Prandtl number, Brownian motion, thermophoresis, heat source, heat absorption, Lewis number, and chemical reaction rate on velocity, temperature, and concentration distributions within the boundary layer. The results indicate that the applied magnetic field retards the flow due to the Lorentz force, while buoyancy forces arising from thermal and concentration differences enhance fluid motion along the stretching surface. Thermal profiles are strongly influenced by internal heat generation, heat absorption, thermophoresis, and fluid thermal diffusivity, whereas nanoparticle concentration is governed by the combined effects of Brownian diffusion, thermophoretic transport, chemical reaction, and mass diffusivity. The analysis highlights the strong coupling between heat and mass transfer mechanisms in nanofluid boundary layers and demonstrates that controlling these parameters can effectively regulate transport processes in applications such as polymer extrusion, cooling of stretching sheets, coating processes, and advanced energy systems.