Conjugate pure mixed convection in a differentially heated lid-driven square cavity with two rotating cylinders

Conjugate pure mixed convection in a lid-driven differentially heated square cavity with two rotating and heat conducting cylinders is numerically investigated by using the finite element method. Three different cases based on the movement of the vertical lids (left and right walls) are considered in this study. The two-dimensional mathematical model includes the system of four partial differential equations of continuity, linear momentum and energy. Flow and thermal fields are investigated for air flowing inside the cavity with four combinations of cylinder rotation, i.e., rotating each cylinder either in clockwise or counterclockwise direction at constant rotational speed, for each different case of direction of lid movement. Parametric simulation is performed with the variation of both Reynolds and Grashof numbers within the range of 10 ≤ Re ≤ 2000 and 100 ≤ Gr ≤ 4 × 106 at fixed Richardson number (Ri = 1). The computational results show that flow patterns and thermal transport within the cavity are greatly affected by the variation of Reynolds number, direction of lid movement and direction of cylinder rotation. It has been observed that the overall heat transfer is remarkably enhanced when only the left lid moves downward and both cylinders rotate in counterclockwise direction.