Brownian motion and micromagnetorotation influence on porous bifurcated arterial flow of tri‐hybrid micropolar‐Casson nanofluid with stenosis and aneurysm

Abstract Effective modulation of blood flow within irregular arterial bifurcations remains essential for improving the treatment of vascular diseases. An unsteady magnetohydrodynamic (MHD) transport model of a tri‐hybrid micropolar‐Casson nanofluid is analyzed through a porous bifurcated configuration. This geometry incorporates uneven stenosis in parent artery and aneurysmal bulges in daughter arteries along its outer walls. The role of micromagnetorotation (MMR), along with a uniform transverse magnetic field, is incorporated to account for microscale rotational dynamics. In this analysis, blood serves as base fluid, fortified with a ternary combination of iron oxide (Fe 3 O 4 ), zinc (Zn), and graphene oxide (GO) nanoparticles. Effects of Brownian motion, heat generation, thermophoresis, and Ohmic heating are incorporated into the analysis. Appropriate non‐similar transformations are employed to reformulate the governing nonlinear partial differential equations (PDEs) into a dimensionless framework, which is further reduced using mild stenosis approximation. Homotopy perturbation method (HPM) is utilized to obtain series solutions. To assess thermodynamic inefficiencies, entropy generation within the arterial flow is evaluated. Fluidic flow, concentration, microrotation, and entropy rate of ternary hybrid nanofluid dominate the other two, while temperature shows the opposite behaviour for both arteries. Fluidic velocity and microrotation of fluid in the parental artery are greater than in the daughter artery. Flow velocity and microrotation are suppressed by increasing microrotational and permeability parameters, but are enhanced by the Casson fluid parameter. These results demonstrate that tri‐hybrid nanoparticles and magnetic modulation can significantly influence flow bifurcation dynamics. Validation against previously reported results demonstrates excellent agreement, confirming the reliability of the present model.