Enhancement of the Hydrothermal Characteristics of Fin-and-Tube Heat Exchangers by Vortex Generators

Geometrical configurations of tubes and vortex generators have been optimized in order to improve the hydrothermal characteristics of fin-and-tube heat exchangers. The work is divided into two parts: the first part concerns the effects of the inclination angle of the oval tube (alpha=0, 10, 20, 30, 40, 50, 60, 70, 80, and 90 degrees); in the second part, the best case resulting from the first part is optimized by using the insertion of flat vortex generators. In this last part, the optimization is investigated by changing the number and position of flat vortex generators on the upper side of the tubes (cases 1 to 7). The obtained results have shown in the first part that the case of alpha=20 degrees ensures an enhancement in the heat transfer coefficient by 1-4% compared with the baseline case (alpha=0 degrees). In comparison with the case of alpha=20 degrees, further enhancement in heat transfer coefficient by about 62.53% has been achieved from the insertion of flat vortex generators. An optimal thermal performance factor of 3.58 has been obtained with the new suggested design (referred to case 7 in this paper).