Three-dimensional MHD Casson-Williamson hybrid nanofluid flow over a stretching sheet in a porous medium

This study investigates the heat transfer and three-dimensional magnetohydrodynamic (MHD) flow of a hybrid nanofluid composed of copper (Cu) and aluminium oxide (Al2O3) nanoparticles dispersed in a 50% ethylene glycol-water base fluid over a stretching surface. The non-Newtonian behaviour is modelled using the Casson-Williamson fluid model. The effects of magnetic field, internal heat generation, and velocity and thermal slip conditions are considered. The governing nonlinear partial differential equations are transformed into ordinary differential equations using similarity transformations and solved numerically via the Runge–Kutta method with a shooting technique. The results show that increasing the Williamson parameter enhances skin friction while reducing heat transfer, with the Nusselt number decreasing from 0.259 to 0.160. The magnetic parameter suppresses heat transfer, reducing the Nusselt number from 0.326 to 0.259, while internal heat generation further decreases it from 0.409 to 0.259. The novelty of this study lies in the combined analysis of Casson-Williamson fluid, hybrid nanofluids, and slip effects in a three-dimensional MHD flow. The findings are relevant to polymer processing and electronic cooling applications.