Electro-osmotic flow of couple stress nanofluid in a stenotic artery with the effects of nanoparticle aggregation and thermal radiation

Purpose This paper aims to investigate the electro-osmotic transport of a couple stress nanofluid through a porous multistenosed artery, considering nanoparticle aggregation and thermal radiation. Their effects on flow dynamics, heat transfer, wall shear stress and the Nusselt number are examined. Design/methodology/approach Blood is modeled as a couple stress fluid, while ZnO nanoparticles are dispersed within the base fluid. The governing momentum and energy equations are formulated under mild stenosis assumptions. Analytical expressions for the velocity and temperature distributions are obtained using the Laplace and finite Hankel transform methods. A parametric sensitivity analysis is performed to evaluate the influence of key physical parameters on the heat transfer rate. Findings Nanoparticle aggregation significantly modifies the effective viscosity and thermal conductivity, enhancing the velocity and temperature compared with the nonaggregation case. Electro-osmotic effects strongly influence the near-wall electric double layer and reduce wall shear stress in the stenotic region. The nanoparticle volume fraction is identified as the dominant parameter influencing the heat transfer rate, with the sensitivity index increasing from 2.588 under nonaggregation conditions to 4.803 under aggregation, representing an 85.6% increase and substantially exceeding the corresponding sensitivity indices of the heat source, Joule heating and thermal radiation. Originality/value This study presents an exact analytical framework for electro-osmotic couple stress nanofluid flow through a porous multiple-stenosed artery with nanoparticle aggregation and thermal radiation, providing insight into nano-blood transport and supporting the development of targeted drug delivery and thermal therapies.