Impact of Cu,Al2O3-water hybrid nanofluid on natural convection inside a square cavity with two heat-generating bodies

Abstract

The natural convection in a square cavity filled with Cu,Al2O3-water hybrid nanofluid and heated from the inside by two heat-generating blocks is numerically investigated. The two blocks, of equal size, generate the same amount of heat and are placed at the same height. The cavity is cooled by the right wall by a constant temperature TC, while it is perfectly insulated by the other remaining walls. The finite volume technique is adopted for the discretization of the differential equations, and then implemented in a numerical code in the Fortran language based on the SIMPLE algorithm. The computational results are then employed to elucidate the impacts of relevant parameters like Rayleigh number (from 103 to 107), nanoparticles fraction (from 0 to 0.08), and the effect of fins installed at the blocks on the thermal field and flow characteristics. The results are presented in terms of streamlines, isotherms, temperature, and local Nusselt number profiles. The results indicate that the increase of the Rayleigh number enhances the heat exchange in the cavity, resulting in a decrease in the maximum temperature. Moreover, adding hybrid nanoparticles (Cu,Al2O3) to the base fluid decreases the temperature by up to 18 %. Finally, the results of this work also indicate that for Ra≤105 the maximum temperature in the cavity can be further decreased by installing the fins at the blocks’ surfaces up to 12 %.