Effects of heater location and heater size on the natural convection heat transfer in a square cavity using finite element method

Finite element method was used to investigate the effects of heater location and heater size on the natural convection heat transfer in a 2D square cavity heated partially or fully from below and cooled from above. Rayleigh Number (5×102 ≤ Ra ≤ 5×105), heater size (0.1 ≤ D/L ≤ 1.0), and heater location (0.1 ≤ xh/L ≤ 0.5) were considered. Numerical results indicated that the average Nusselt Number (Num) increases as the heater size decreases. In addition, when xh/L is less than 0.4, Num increases as xh/L increases, and Num decreases again for a larger value of xh/L. However, this trend changes when Ra is less than 104, suggesting that Num attains its maximum value at the region close to the bottom surface center. This study aims to gain insight into the behaviors of natural convection in order to potentially improve internal natural convection heat transfer.