Analyzing flow and thermal behavior in laminar mixed convection: Effects of rotating cylinder located at various side walls

The present study investigates numerically the laminar mixed convection problem in a square enclosure with a mounted rotating cylinder at different sidewalls. The goal is to characterize the geometrical model that performs the best and offers the highest heat transfer rate by relocating the rotating cylinder. The effect of the cylinder angular speeds defined by Re number for a wide range of (100 ≤ Re ≤ 1200) and Grashof number of (7x10^3 ≤ Gr ≤ 4.9x10^4), and the effect of the cylinder radius R_0, on the heat transfer characteristics are considered. The suggested geometry is a square cavity with a bottom wall that is immobile and heated to a temperature of T_h and with rotating cylinders mounted at different sidewalls and maintained at cold temperature T_c. Remaining walls are considered adiabatic. Results revealed that flow patterns and thermal performance are directly affected by the placement location of both the chosen heated wall and the rotating cylinder. From the four investigated geometrical models, case A (cold cylinder located at the top wall of the cavity + cavity left wall heated), was found to be the best performing geometrical model in the range of the investigated flow and thermal parameters with a maximum value of N_u,max = 9.183 for R_i = 0.034. It was also found that increasing the rotating cylinder radius R_0 leads to an enhanced heat transfer rate.