In this study, heat transfer and thermal performance of a periodically dimple-protrusion patterned surface have been … investigated to enhance energy-efficiency in compact heat exchangers. The local heat transfer coefficients on the dimple … applied to the bottom wall only or both the bottom and top walls in the test duct. The ratio of dimple (or protrusion) depth …

design variables, such as the elliptic dimple diameter ratio, ratio of the dimple depth to average diameter, and ratio of the …-optimal front with regard to the heat transfer and pressure loss, respectively, have spanwise and streamwise elliptic dimple shapes …

structures including bleeding dimples, longitudinal vortex generators (LVGs), and compound dimple-LVG. The simulation results … show that the oval tube with compound LVG-dimple achieves the highest overall heat transfer performance while the oval tube … on the first row of tubes together with hemisphere protrusions design, while the compound LVG-dimple on the rest tubes …