Numerical predictions using LBM application: laminar mixed convection of non-Newtonian nanofluids in ventilated square cavities

Abstract

In this paper, we investigate numerically the flow field and heat transfer of a viscoplastic nanofluid flowing within ventilated devices. The incompressible nanofluid with constant and uniform physical and rheological properties is composed of silver nanoparticles suspended in a non-Newtonian base fluid that obeys the Bingham rheological model. This numerical study is based on the multiple-relaxation-time Lattice Boltzmann method (MRT-LBM). The two-dimensional nine-velocity (D2Q9) model is adopted to solve the flow field, while the two-dimensional five-velocity (D2Q5) model is developed to solve the temperature field. The impact of various pertinent parameters, such as Richardson (0.01 ≤ Ri ≤ 100), Bingham (0 ≤ Bn ≤ 20), and Prandtl numbers (1 ≤ Pr ≤ 30), is widely inspected, side by side with the nanoparticles volume fraction (0 ≤  ≤ 10%). The obtained results show the important effect of these parameters, which cannot be neglected, on both flow and heat transfer structures, in this type of cavities.