Exploring the impact of variable viscosity on thermal mechanics in Casson hybrid nanofluid flow in a porous channel

This study explores the mixed convective and heat transfer flow characteristics of a Casson hybrid nanofluid, consisting of gold ( Au ) and titanium ( Ti ) nanoparticles suspended in blood, traversing a vertical channel within a porous medium. Motivated by the growing relevance of nanofluids in biomedical applications, particularly in targeted drug delivery and hyperthermia-based cancer treatments, this work aims to understand how variable viscosity and thermal conductivity influence heat transfer enhancement. The research addresses a key gap in the literature by modeling a non-Newtonian blood-based hybrid nanofluid using Casson fluid theory, which better represents the rheological properties of blood compared to Newtonian assumptions. The governing nonlinear momentum and energy equations are obtained and translated by similarity transformations, and hence, solved numerically using MATLAB's BVP5C technique. Quantitative results show that the incorporation of nanoparticles enhances the heat transfer rate by up to 21.7 % compared to the nanofluid and 46.06 % to the viscous fluid. Additionally, variable viscosity significantly modulates flow velocity, while variable thermal conductivity sharply constrains thermal diffusion. Velocity and temperature contour plots, accompanied by the tabulated skin friction and Nusselt number, provide a detailed overview of parameter effects. The novelty of this work lies in the absorption of blood-based Casson hybrid nanofluid with variable thermophysical properties, enabling a more realistic model for biomedical heat transfer processes. This model holds promise for optimizing cooling techniques in therapeutic procedures and designing advanced drug delivery systems.