Effects of a rotating cylinder with blades on the hydrothermal flow of a hybrid nanofluid in a vented cavity

This paper presents a numerical investigation for the mixed convection flow of a hybrid nanofluid in a vented cavity under the impact of a rotating bladed cylinder. The dynamic mesh approach is applied to simulate the flow domain and the boundary motion of the rotating bladed cylinder. Governing equations are computationally solved utilizing the finite volume technique. These equations are assumed to be two-dimensional, unsteady, and laminar for an incompressible mixed convection flow. A Newtonian hybrid nanofluid of (SiO2-Al2O3/ water) is suggested as a working fluid. Simulations of different locations of cylinders and shapes of blades or fences were examined. A wide range of pertinent parameters such as nanoparticle concentrations (0 ≤ φ1 ≤ 0.03 and 0 ≤ φ2 ≤ 0.03), cylinder radiuses (0.1 ≤ R ≤ 0.3), cylinder locations (0.25 ≤ δ ≤ 0.75), angular rotational speeds (- 5 ≤ Ω ≤ 5), Grashof numbers (103 ≤ Gr ≤ 105) and Reynolds numbers (200 ≤ Re ≤ 1000) were investigated, Various qualitative and quantitative data were presented to show the influence of these parameters on the hydrothermal flow within the considered cavity. The outcomes revealed that the hydrothermal characteristics were significantly affected by Re, Gr, R, δ, Ω, and the direction of the rotating cylinder. The heat transfer rate was improved by raising the number of blades of the rotating cylinder at Re=1000, and it was slightly affected by its shape. According to the stationary bare cylinder, the maximum improvement in heat transfer rate happens at Re=1000, δ=0.25, R=0.25, Ω= -5. Eventually, further improvement in heat transfer rate was achieved by increasing the solid nanoparticles concentration of the hybrid nanofluid.