Comparative study of fluid flow and heat transfer characteristics on the three kinds of fin-tube heat exchanger with delta winglets longitudinal vortex

In the present study, the heat transfer and fluid flow characteristics of fin-tube heat exchangers of circular-tube, equal-diameter elliptic-tube and equal-perimeter elliptic-tube with delta winglets longitudinal vortex was presented based on the numerical simulation. The result showed that the temperature and velocity field of equal-perimeter elliptic-tube fin heat exchanger more uniform, and its heat transfer performance was the best, and the Nu number of equal-diameter elliptic-tube fin heat exchanger was the largest,which was 2.2%~6.1% higher than that of circular-tube heat exchanger with delta winglets, 6.5%~8.3% higher than that of equal-radius elliptic-tube heat exchanger and with delta winglets and 29.1%~33.5% higher than that of flat fin-tube heat exchanger. Considering from the overall performance, the delta winglets longitudinal vortex oval fin-tube heat exchanger fit for moderate and high Reynolds numbers.