Numerical simulation study of enhanced heat transfer and flow resistance characteristics of twisted tape and twisted elliptical tube composite

In this paper, the numerical simulation method is used to explore the effect of wall twisting and twisted tape composite to enhance heat transfer in tubes. Comparative analysis of the flow characteristics of fluids in tubes with different Reynolds numbers between 10,000 and 20,000, and with different length/short axis ratios and twist ratios. The results showed that when the length/short axis ratio of twisted elliptical tubes is increased from 1.30 to 2.15, the Nusselt number of twisted elliptical tubes with inserted twisted tapes increases by 10.5–28.6% and the friction coefficient increases by 101.5–128.8% compared with that of smooth elliptical tubes. When the twist ratio is reduced from 2/3 to 1/6, the Nusselt number of the twisted elliptical tube with inserted twisted tape increases by 9.8–37.7%, and the friction coefficient increases by 101.9–164.7%. Increasing the length/short axis ratio and decreasing twist ratio can help to improve the heat transfer performance of the twisted elliptical tube, but all of them are at the expense of increasing the resistance to flow of the fluid inside the tube.