Magnetohydrodynamic boundary-layer flow of a nanofluid over a stretching sheet with Dufour and Soret impact for non-isothermal and non-isosolutal conditions: A Chebyshev Collocation Approach

This current study investigates the steady, incompressible boundary-layer flow of an aluminium oxide (Al₂O₃)–water (H₂O) nanofluid, where Aluminium oxide nanoparticles are suspended in water to form an Al₂O₃/H₂O nanofluid under non-isothermal and non-isosolutal conditions. The analysis incorporates thermo-diffusion (Soret effect) and diffusion-thermo (Dufour effect) to account for coupled heat and mass transfer mechanisms within the flow field. In addition, the governing model considers the influence of an applied magnetic field, which introduces magnetohydrodynamic resistance, together with convective boundary conditions to realistically describe heat exchange at the surface. The resulting mathematical formulation consists of coupled nonlinear partial differential equations representing conservation of mass, momentum, energy, and concentration. Through appropriate similarity transformations, these equations are condensed to a system of nonlinear ordinary differential equations accompanied by transformed boundary conditions. The numerical solution of the governing equations is obtained using the Chebyshev Collocation Method, which provides accurate approximations for highly nonlinear boundary-layer problems. To validate the numerical procedure, the computed Nusselt number is compared with existing results reported in the literature, and close agreement is demonstrated through tabulated comparisons. The findings reveal that an increase in the magnetic parameter suppresses fluid velocity due to enhanced Lorentz force resistance, while simultaneously increasing temperature and concentration distributions. Furthermore, higher Dufour and Soret numbers significantly enhance thermal and concentration profiles, respectively. The nanoparticle volume fraction is also observed to improve heat and mass transfer characteristics. These outcomes suggest that incorporating aluminium oxide nanoparticles into water enhances thermal conductivity, thereby offering promising applications in advanced cooling technologies and energy-efficient systems aimed at reducing carbon emissions.