Thermal performance and entropy generation in transient MHD nanofluid flow over a vertical plate and cone with anisotropic effects

The study analyzes transient magnetohydrodynamic (MHD) ternary nanofluid flow over two distinct geometries; a vertical plate and cone under the influence of coupled transport mechanisms, emphasizing how geometry alters thermal and momentum characteristics. A ternary hybrid nanofluid consisting of Fe 3 O 4 , Al 2 O 3 and MWCNT nanoparticles dispersed in water in a 1:2:1 ratio is considered to improve the thermal transport characteristics. The flow is modeled by incorporating viscous dissipation, magnetic field, thermal radiation, heat source/sink and Ohmic heating under convective boundary conditions. In contrast to conventional isotropic conditions, the study considers the geometry to be embedded in an anisotropic porous medium, allowing the effects of directional permeability to influence the transport characteristics. The transient nature of the flow is considered to examine the temporal evolution of the momentum and thermal boundary layers. The transformed governing equations are solved numerically using the Crank-Nicolson implicit finite difference scheme. The numerical results indicate that the thermo-fluid characteristics are strongly affected by the magnetic field, viscous energy dissipation, and enhanced thermal conductivity associated with nanoparticle dispersion.Compared to the vertical plate, the cone geometry exhibits lower velocity and thermal boundary layer thicknesses due to the influence of geometric curvature on fluid flow and heat transfer mechanisms. Furthermore, the cone geometry yields improved surface heat transfer rates because of the stronger temperature gradients near the surface. Entropy generation analysis demonstrate that irreversibility is primarily driven by combined effects of viscous dissipation, magnetic field interaction and porous resistance. Thermal radiation and nanoparticle dispersion increase the thermal irreversibility of the system. The study provides insight into the design of energy-efficient thermal systems where minimizing irreversibility is critical.