@article{Boonloi_2016, title={Numerical Analysis on Flow and Heat Transfer Characteristics in A Circular Tube with Various Flow Attack Angles of Punched Delta Winglet Vortex Generators}, volume={4}, url={https://ajouronline.com/index.php/AJAS/article/view/3743}, abstractNote={Numerical investigations on heat transfer profile and flow topology in a circular tube heat exchanger with various parameters of punched delta winglet vortex generators are reported. The effects of the flow blockage ratios, BR = 0.10 – 0.30, Reynolds numbers, Re = 100 – 2000, flow attack angles, α = 0o, 15o, 30o and 45o are investigated on both downstream and upstream arrangements. As the results, the presence of the punched delta winglet vortex generators in the tube heat exchanger can enhance the heat transfer rate and thermal performance higher than the smooth tube with no generators. The swirling flow, vortex flow, impinging flow and turbulent mixing are phenomenal when installing with the punched delta winglet vortex generators in the tube that help to improve heat transfer rate and thermal performance. The optimum TEF is found when using the punched delta winglet vortex generators with BR = 0.30, Re = 2000, α = 30o for upstream case. In addition, the use of the punched delta winglet vortex generators with the low flow blockage area can help to reduce the pressure loss in the heating system.}, number={2}, journal={Asian Journal of Applied Sciences}, author={Boonloi, Amnart}, year={2016}, month={Apr.} }