Entropy-Optimized Electro-Osmotic Transport of Bingham–Papanastasiou Hexa-Hybrid Nanofluids with Gyrotactic Microorganisms and Thermal Radiation in Porous Stenosed Arteries

Cardiovascular disorders associated with arterial stenosis continue to pose significant clinical challenges, necessitating advanced computational models for understanding complex hemodynamic and thermal transport phenomena in diseased arteries. The present study aims to investigate entropy generation in unsteady pulsatile electro-osmotic blood flow of Bingham–Papanastasiou hexa-hybrid nanofluids through a porous stenosed artery under the influences of variable viscosity, thermal radiation, and gyrotactic microorganisms. Blood is modeled as a non-Newtonian fluid based on the Bingham–Papanastasiou relation to represent yield-stress behavior accurately. Besides, electro-osmotic transport is modeled with the Debye–Hückel formula. The pore-structured arterial wall and stenotic shape are represented through Darcy’s law and changing arterial constriction, respectively. Meanwhile, the heat transfer augmentation due to hexa-hybrid nanoparticles and the mechanism of microorganism transport are accounted for too. The dimensionless equations of balance for the momentum, energy, microorganism concentration, entropy generation, and Bejan number are solved numerically by using an implicit finite difference scheme. Numerical computation shows that enhancement of electro-kinetic parameter making axial blood velocity and volumetric flow rate to increase drastically and flow impedance to go down significantly. Larger Bingham as well as viscosity variation parameters, on the other hand, act against fluid motion as the resistance due to yield-stress becomes more prominent. Besides, thermal radiation increases temperature level and entropy generation while gyrotactic microorganisms lead to a considerable change in nanoparticle transport features. These findings provide new physical insights into entropy-optimized electrokinetic transport of multi-component nanofluids in stenosed arterial systems, with potential applications in targeted drug delivery, hyperthermia treatment, and biomedical microfluidic design.