This paper reported experimental and numerical simulation investigations on heat transfer characteristics of polygonal twisted elements in the constant wall temperature with Reynolds number (Re) ranging from 200 to 1800. In this study, the results revealed that the entransy efficiency (η) increased with the polygonal twisted element’s edge number increasing. Moreover, the highest entransy efficiency η of the quadruple-edge continuous twisted element (QEC) heat exchange tube was 93.97%. Besides, the field synergy performance also showed a positive correlation with the element edge number. A maximum increase of 57% was observed in the field synergy number (Fc) of the QEC insert as compared with the plain tube while the performance evaluation criteria (PEC) had little relationship with the element edge number. In the case of the interlaced twisted elements, both the PEC value and the entransy efficiency η were lower than the corresponding continuous ones. In addition, the Fc values were not apparent, of which the maximum difference was only 7% in the two cases(continuous twisted element and interlaced twisted element). In Re= 1800, when the d/D(the ratio of the twisted element diameter to the inner diameter of the tube) of the QEC heat exchange tube increased, the PEC values and Fc values both increased significantly. The maximum PEC value was 1.62 and the maximum Fc values was 202% higher than the plain tube. Subsequently, the entransy efficiency η got the maximum value in the range of d/D = 0.375-0.75. The maximum entransy efficiency was 91.07%.

本文报道了在壁温恒定的情况下多边形扭曲元素的传热特性的实验和数值模拟研究，雷诺数（R e）为200至1800。在这项研究中，结果表明，传热效率（η）随着多边形扭曲元素的边数增加。而且，最高传输效率η四边连续扭曲元件（QEC）换热管的热效率为93.97％。此外，场协同性能也与元素边数呈正相关。与普通管相比，QEC插件的场协同数（Fc）最大增加了57％，而性能评估标准（PEC）与元素边缘数几乎没有关系。在隔行扭曲元件的情况下，PEC值和传输效率η均低于相应的连续元件。另外，Fc值不明显，在连续扭曲元件和隔行扭曲元件这两种情况下，其最大差异仅为7％。在R e当1800 = 1800时，当QEC换热管的d / D（扭曲的元件直径与管的内径之比）增加时，PEC值和Fc值均显着增加。与平管相比，最大PEC值为1.62，最大Fc值高202％。随后，传输效率η在d / D ＝ 0.375-0.75的范围内达到最大值。最大传输效率为91.07％。