Thermal exploration of EMHD Al 2 O 3 -Graphene/H 2 O hybrid nanofluid over a stretching sheet with Cattaneo-Christov heat flux model- A numerical analysis

This study investigates the electro-magnetohydrodynamic (EMHD) flow of a hybrid nanofluid consisting of aluminum oxide and graphene nanoparticles suspended in a water-based fluid over a bidirectional stretching sheet. The Cattaneo-Christov (CC) thermal flux model is used to analyze the thermal relaxation time. Furthermore, an entropy analysis was conducted to minimize energy loss and improve efficiency. The solution strategy involves applying similarity transformations to the governing PDEs, yielding ODEs, which are subsequently solved numerically using the Keller-Box method. The outcome is a graphical representation of velocity and temperature distribution. The velocity profile decreases as the magnetic parameter increases, whereas the temperature profile rises. Moreover, the electric field strength exhibits a detrimental effect on heat transfer, enhancing the heat transfer rate. The heat transfer rates improved significantly as the nanoparticle volume fraction increased from 1% to 10%. In particular, the heat transfer rates increased by 5.44% using a volume fraction of 10% Al2O3/H2O. However, a more remarkable enhancement of 15.94% achieved with a 10% volume fraction of Al2O3+Graphene/H2O. This study found that the hybrid nanofluid Al2O3+Graphene outperformed the traditional nanofluid Al2O3/H2O regarding heat transfer enhancement, especially at higher volume fractions. This study reveals that entropy generation decreases with increasing electric field strength and increases with rising magnetic field strength.