Numerical Investigation of Unsteady Magnetohydrodynamic Casson Hybrid Nanofluid Flow Through a Stenosed Artery: Effects of Viscous Dissipation, Joule Heating, Thermal Radiation and Chemical Reaction

This study numerically investigates the unsteady magnetohydrodynamic (MHD) flow of a blood-based Casson hybrid nanofluid containing gold (Au) and iron oxide (Fe3O4) nanoparticles, flowing through a stenosed artery. The viscous dissipation, Joule heating, thermal radiation and porosity effects, along with a first-order homogeneous chemical reaction, are included in the mathematical model. A semi-implicit Crank–Nicolson finite-difference scheme is applied to solve the governing dimensionless equations in a MATLAB package, and the numerical method is tested for grid independence and benchmarking with other available solutions. The results indicate that the axial velocity is reduced with increasing Hartmann number; however, the increasing Reynolds number, Darcy number and Casson parameters increase the flow. The temperature is increased by the viscous dissipation and Joule heating as the Eckert number increases, and the thermal boundary layer is decreased as the Prandtl and radiation parameters increase. Increasing the volume fraction of nanoparticles has increased the skin friction and heat transfer, while the chemical reaction and Schmidt numbers have reduced the concentration field. Greater stenosis severity significantly suppresses momentum, heat and mass transport. The proposed model provides useful insight into the combined effects of magnetic fields, hybrid nanoparticles and arterial stenosis on blood flow, heat transfer and reactive species transport, with potential applications in magnetically guided drug delivery and cardiovascular thermal therapies.