Heat transfer behavior of flat plate having 45° ellipsoidal dimpled surfaces

Flat surface with ellipsoidal dimple of external flow was investigated in this study.10 types of dimple arrangements and dimple intervals are studied. The stream of air flows over the heated surface with dimples. The velocity of the air stream varies from 1 to 5 m/s. The temperature and velocity of air stream and temperature of dimpled surfaces were measured. The heat transfer of dimpled surfaces was determined and compared with the result of smooth surface. For the staggered arrangement, the results show that the highest heat transfer coefficients for dimpled surfaces are about 15.8% better than smooth surface as dimple pitch of ST/Dminor=3.125 and SL/Dminor=1.875 yield the highest heat transfer coefficient values. And for the inline arrangement, the results show that the heat transfer coefficients for dimples surfaces are about 21.7% better than smooth surface as dimple pitch of ST/Dminor=1.875 and SL/Dminor=1.875 yield the highest heat transfer coefficient values.