Analysis of entropy generation in MHD flow of ternary nanofluids with variable properties through a porous medium

This study aims to analyze the entropy generation and heat transfer in magneto-hydrodynamic flow of MgO-ZnO-Cu/H₂O ternary nanofluids over an exponentially stretching porous sheet, under the combined effects of thermal radiation, Joule heating, and porosity. The Tiwari-Das model with temperature-dependent viscosity, thermal conductivity, and variable Prandtl number is employed. The governing equations, transformed via similarity variables, are solved numerically using MATLAB's bvp4c solver. Nanoparticle size and shape effects are neglected while only volume fractions and bulk properties are considered. The results show that increasing Eckert, Brinkman, magnetic, and radiation parameters elevates temperature and entropy generation, while higher magnetic fields reduce fluid velocity. Specifically, ternary nanofluid temperature rises by 63.75% and hybrid nanofluid by 65.76% as the radiation parameter increases from Rd = 0.2 to Rd = 0.8; entropy production drops noticeably with higher Brinkman number and when shifting from ternary to hybrid or mono nanofluids. These findings provide insights for optimizing nanofluid properties to enhance thermal performance and minimize energy losses, with applications in aerospace, advanced cooling systems, wire drawing, and biomedical engineering.