Entropy Optimization of Thermo-Magneto-Solutal Stratification of Ellis Hybrid Nanofluids Flow Through Shrinking Stenotic Artery with Activation Energy

This study numerically investigates the magnetohydrodynamic flow and heat–mass transfer characteristics of an Ellis hybrid nanofluid (Cu–Fe 3 O 4 /blood) through a shrinking stenotic artery under the influence of nonlinear thermal radiation, viscous dissipation, and a binary chemical reaction with activation energy. Convective slip boundary conditions are imposed at the arterial wall for velocity, temperature, and concentration. The governing equations are transformed into non-dimensional form using similarity transformations and solved numerically through the bvp4c scheme in MATLAB. Dual solution branches are obtained and analyzed for velocity, temperature, concentration, skin friction, Nusselt number, Sherwood number, and entropy generation. The application of a magnetic field and nonlinear thermal radiation elevates the fluid temperature, as reflected in an approximately [Formula: see text] increase in the Nusselt number, thereby promoting enhanced thermal transport. The entropy generation analysis reveals that thermodynamic irreversibility can be reduced by up to approximately [Formula: see text] through appropriate regulation of nanoparticle volume fractions and magnetic field strength. Overall, the hybrid nanofluid consistently exhibits lower entropy generation than its single nanofluid counterpart, demonstrating its thermodynamic superiority and potential applicability in biomedical thermal therapies and targeted cardiovascular treatments.