Numerical analysis of entropy generation and heat transfer of ternary nanofluids under a periodic magnetic field in a square enclosure

Ternary nanofluids are a new class of working fluids that exhibit greater heat transfer and stability properties than single nanofluids. The main goal of the present work is to investigate the effects of a periodic magnetic field on natural convection and entropy generation in a square enclosure filled with a ternary nanofluid (Cu-Al2O3-Fe3O4-water). To achieve the stated purpose, the equations that govern energy, mass, and momentum conservation are first constructed and then transformed into non-dimensional forms using the notion of parameters with no dimension. Secondly, they are numerically solved by the Control Volume Finite Element Method (CVFEM), and the entropy generation number is calculated. The effects of active parameters such as the Rayleigh number, the volume fraction of nanoparticles, the Hartmann number, and the period number, are investigated concerning the average Nusselt number and the entropy generation number. The results were compared with those of the literature and good agreement was observed. The results discovered that there is a maximum value for Nuave and a minimum value for Ngen when the period number is changed for a given Hartmann number. Nuave and Ngen have the highest and lowest values at lambda = 0.7 and lambda = 0.6, respectively. Also, the value of Ngen decreases 16.7 % at Ha = 25 when a single nanofluid is replaced by a ternary nanofluid.