Wang Li, Ni Peiyong, Xi Guannan
School of Mechanical Engineering, Nantong University, Nantong, 226019, Jiangsu Province, China.
Sci Rep. 2021 Mar 25;11(1):6844. doi: 10.1038/s41598-021-86285-0.
This study is conducted to investigate the effect of off-center placement of twisted tape on flow distribution and heat transfer in a circular tube. The effect of tape width of 20, 18, 16, 14 and 12 mm on the heat transfer performance is discussed under the same twist ratio of 2.0. The numerical analysis of the flow field, average Nusselt number, friction factor and thermo-hydraulic performance parameter of the tube are discussed with Reynolds number ranged from 2600 to 8760. The results indicate that the Nusselt number of the tube fitted with center-placed twisted tapes at various width is 7-51% higher than the plain tube, and performance in low Reynolds region was found more effective than that in high Reynolds region. The heat transfer for circular tube with twisted tape attached to the wall shows better performance than that for the tube with center-placed twisted tape. With a smaller tape width, a higher increasing ratio of Nu-wall/Nu-center is obtained. The increasing ratio for Nusselt number ranged from 3 to 18%. However, the use of twisted tape inserts is not beneficial for energy saving. The thermo-hydraulic performance parameters for convective heat transfer of helium gas flowing in a circular tube are below unity for the calculated Reynolds region.
本研究旨在探究麻花带偏心放置对圆管内流动分布和传热的影响。在相同捻距2.0的情况下，讨论了宽度为20、18、16、14和12毫米的麻花带对传热性能的影响。在雷诺数范围为2600至8760的条件下，对管内流场、平均努塞尔数、摩擦系数和热工水力性能参数进行了数值分析。结果表明，不同宽度的中心放置麻花带的管的努塞尔数比光管高7 - 51%，且在低雷诺数区域的性能比高雷诺数区域更有效。壁面附着麻花带的圆管的传热性能优于中心放置麻花带的管。麻花带宽度越小，Nu-wall/Nu-center的增加率越高。努塞尔数的增加率在3%至18%之间。然而，使用麻花带插入物不利于节能。在所计算的雷诺数区域内，圆管内氦气对流换热的热工水力性能参数低于1。
