Impacts of magnetic and buoyancy forces on mixed convection nanofluid flow in an inclined exhaust geometry considering the KKL correlation and thermal radiation

Abstract

The main goal of this research is to examine the interacting impacts of buoyancy force, thermal radiation, nanoparticles concentration and magnetic force on thermal behaviors of mixed convection alumina-water nanofluid flow in an inclined Exhaust geometry. This geometry includes two inclined forward facing steps (FFSs) which are symmetrically located on the top and bottom walls of an inclined channel. These inclined steps are modeled in Cartesian coordinates by applying the embedded boundary method. The governing equations are numerically solved by means of the finite volume method and SIMPLE algorithm. The Rosseland approximation is adopted to calculate the radiative heat transfer term in the energy equation. Influences of Brownian motion on the effective thermal conductivity and viscosity of nanofluid is considered by applying the KKL correlation. The results are shown for various values of Grashof number (Gr = 0 − 30, 000), the Exhaust inclination angle (γ = 0° − 90°), radiation parameter (Rp = 0 − 1), Hartmann number (Ha = 0 − 200) and alumina nanoparticles concentration (ξ = 0 − 0.04). The predicted results indicate that the Gr,  γ,  Rp and Ha parameters have a considerable impact on the temperature distributions inside the bottom half domain of the Exhaust, whilst the influence of ξ parameter on these distributions is very small and ignorable. Furthermore, the maximum value of total heat transfer rate happens in the vertical Exhaust with highest values of Gr,  Rp,  Ha and ξ parameters (γ = 90°,  Gr = 30, 000,  Rp = 1,  Ha = 200,  ξ = 0.04). Comparing the numerical results of the present study with the results of other benchmark problems shows excellent agreement.