Entropy generation and shape effects analysis of hybrid nanoparticles (Cu-Al₂O₃/blood) mediated blood flow through a time-variant multi-stenotic artery

The objective of this study is to analyze entropy generation effects on the flow of blood through a time-variant multi-stenotic artery assuming blood to be non-Newtonian Casson fluid. The nanoparticles (copper and alumina) of different shapes (sphere, cylinder, and blade) are injected into the artery, which combines with blood to form a hybrid nanofluid. In consideration of the magneto-hemodynamic effect, a uniform magnetic field is applied transverse to the blood flow. The viscosity of blood is assumed as temperature dependent; therefore, the Reynolds viscosity model is taken into account for the variable viscosity of blood. The Crank–Nicolson scheme has been applied to the governing equations and boundary conditions of the fluid flow. Important hemodynamic factors like velocity, temperature, and heat transfer coefficient are calculated at a specific critical height of the stenosis. The second law of thermodynamics is used to explore entropy generation, and the effects of the entropy generation number (N_s) and Bejan number (Be) are examined. The current model has been validated through comparison with existing work, and it is demonstrated to be in excellent agreement with the earlier work. It is observed that the temperature profiles enhance with the Casson fluid parameter, whereas there is a declination in heat transfer coefficient profiles. The temperature difference parameter is the most important and has a significant impact on entropy among the three non-dimensional parameters for entropy minimization: magnetic number, Brinkman number, and temperature difference parameter. The suspension of metallic or non-metallic nanoparticles into the bloodstream makes it applicable for utilization in nano-hemodynamics, blood purification systems, nano-pharmacology, and the treatment of hemodynamic ailments.