Impact of Fe ₃ O ₄ Nanoparticle Aggregation and Magnetic Field on Non-Newtonian Blood Flow in Atherosclerotic Artery

Magnetic Fe ₃ O ₄ (magnetite) nanoparticles have been extensively used as powerful agents in biomedical applications due to their good biocompatibility and ability to form field-induced chain-like aggregates that significantly improve thermal and magnetic performance in areas such as targeted drug delivery, magnetic hyperthermia, and MRI contrast enhancement. This study examines the impact of Fe ₃ O ₄ (magnetite) nanoparticle aggregation on the magnetohydrodynamic (MHD) flow and heat transfer characteristics of blood as a non-Newtonian nanofluid in a stenosed artery. The non-Newtonian behavior of blood is modeled by the Cross-fluid model, and the momentum and energy governing equations include the effects of an applied magnetic field (magne-tohydrodynamics), viscous dissipation, and Joule heating. A key novelty of this study is that the dynamics of magnetic nanoparticle aggregation are explicitly considered. The scaled and non-dimensionalized equations are solved numerically using the forward-in-time central-in-space (FTCS) numerical scheme. The results show that the aggregation of nanoparticles significantly affects the velocity profile, wall shear stress, temperature distribution, and volumetric flow rate in the stenotic region. These results provide new physical insights into the optimization of magnetite-based blood nanofluids for magnetic hyperthermia, targeted drug delivery, and hemo-dynamic control of atherosclerotic vessels. The combined effects of blood rheology, magnetic field strength, and nanoparticle aggregation offer an effective mechanism to control blood flow, temperature, and resistance in stenosed arteries.