Analysis of Heat Transfer Characteristics of a Al2O3-SiO2/Water Hybrid Nanofluid in a Localized Heated Porous Cavity

Hybrid nanofluid has been standardized as a novel type of nanofluid, distinguished by its thermal properties and potential utilities that serve to accelerate heat transfer. The present problem scrutinizes the natural convective heat transfer characteristics of hybrid nanofluid (Al2O3-SiO2/water) in a square porous cavity. A partial section of the bottom wall of the cavity is being heated while the rest portion of the bottom wall and top wall are considered as adiabatic. Further, the side walls are kept at lower temperature than the heated portion. The finite element method with penalty parameter is used to solve the dimensionless nonlinear coupled partial differential equations of the flow problem. A comparison of results with previous study has been made under special case which shows a good consistency. The results are demonstrated in terms of streamlines, temperature contours, and avg Nusselt number over wide ranges of governing parameters, namely Darcy number (Da), Rayleigh number (Ra), different lengths of heated zone (epsilon), and volume fraction of nanoparticles (phi). The obtained results show that with an increase in percentage of hybrid nanofluid and Darcy number, heat transfer and intensity of circulation augments. It is also observed that rate of heat transfer in porous medium enhances with increment in volume fraction of nanoparticles.