In this study, the flow characteristics and heat transfer performances of the enhanced tube with teardrop dimples were numerically analysed and compared with spherical/elliptical dimples. Additionally, the effects of dimple depth, pitch and radius on turbulent fluid flow and heat transfer performances were also being discussed. From this investigation, it is found that the strength and extent of the recirculation flow induced by teardrop dimple is significantly decreased when it compared with the spherical/elliptical dimples, which caused greatly improvement of heat transfer performance for ETTD. In addition, the teardrop dimple can reduce the pressure loss due to the fluid flows smoothly and easily on the streamline surface. The Nu and f of ETTD increases with the increasing of dimples depth and radius, and decrease with increasing of pitch. Among considered geometric parameters and operating condition, the ETTD with D = 2 mm, P = 15 mm, R = 4 mm and Re = 5,000 obtained the largest PEC value about 2.06. (C) 2018 Elsevier Ltd. All rights reserved.