Computational Multieffect Analysis of Blood-Based Trihybrid Nanofluid Flow With Nanoparticles Through a Stenotic...

This study is aimed at examining the computational modeling of the blood flow of a trihybrid nanofluid with nanoparticles such as Ag, Au, and Cu to simulate the hemodynamics parameters and heat transfer within a constricted channel geometry that directly parallels the flow conditions in a stenosed artery. The flow is defined as an unsteady, incompressible, laminar Newtonian fluid, with blood exhibiting Newtonian properties at elevated shear rates. An algorithm for mass, velocity, and energy, as well as a fine element-sized mesh, was developed using the computational fluid dynamics (CFD) technique based on the finite element method. Here, systematic observation of the effect of varying nanoparticle volume fractions (ϕ = 3%, 9%, 15%) and Reynolds numbers (Re) on the resulting flow velocity profiles. Although maximal velocity is geometrically concentrated at the stenosis throat, the critical determining factor of patient danger is the concentration-dependent change in fluid viscosity. Increasing ϕ raises effective viscosity (Brinkman model), progressively flattening the velocity profile into a blunt, plug-like regime; paradoxically, this near-uniform plug, lacking the gradual wall-to-core velocity gradient of a parabolic profile, is unable to resist the adverse pressure gradient at the abrupt poststenotic expansion, causing simultaneous cross-sectional deceleration and abrupt flow separation that sustains larger, more energetic recirculation zones than those observed at lower ϕ. This disturbed distal flow that generates large and persistent recirculation zones downstream of the stenosis, which are associated with increased thrombotic risk due to disturbed flow patterns. Conversely, the increase in ϕ drastically increases thermal conductivity, making the heat transfer process nearly independent of flow speed, that a key insight for forthcoming contained thermal therapies. Eventually, this research delivers a mechanistic link between fluid rheology, flow instability, and thrombotic risk, signifying that therapeutic strategies need to prioritize the management of fluid viscosity to stabilize poststenotic flow fields and mitigate associated cardiovascular complications. This work is the first effort to evaluate the impact of trihybrid nanofluid rheology on the exacerbation of poststenotic flow instability at clinically relevant Re. This reveals that a critical higher nanoparticle loading (ϕ) improves thermal conductivity. The present findings have direct significance for biomedical applications like targeted photothermal therapy (PTT), antimicrobial vascular intervention, and nanoparticle-mediated drug delivery in cardiovascular disease management. The computed 18% enhancement in conductive heat flux at ϕ_T = 15% further establishes a quantitative performance baseline for the design of nanofluid-based thermal management systems in biomedical microdevices.