Heat transfer augmentation using winglet with punched holes

Heat transfer performance of fin-tube heat exchanger can be augmented by the use of longitudinal vortex generators which generates longitudinal vortices. In the present work experimentations have been performed to investigate the heat transfer and flow resistance characteristics of rectangular winglet pair (RWP) type vortex generators (VGs) mounted on fin surface in a fin-tube heat exchanger. RWP have been placed in Common Flow Down (CFD) configuration in downstream location. Heat transfer and flow resistance characteristics have been compared between both the cases (i.e. winglet with punched hole and winglet without punched hole) using Colburn’s factor(j), friction factor(f) and performance evaluation criterion (PEC) also known as area goodness factor = j / f. Investigations have been performed considering the Reynolds number in the range of 1500 to 9000 and angle of attack as 45°. The vortex generator considerably improves the thermohydraulic performance and decreases the flow resistance due to a reduction in the face area. The result clearly indicates that the rectangular winglet pair with punched hole gives the better thermohydraulic performance.