The application of wire coil as a turbulent generator to enhance the heat transfer in heat exchangers is constantly being studied and presented. In this work, a novel wire coil turbulator was developed to have characteristics that are different from those previously proposed. It is based on the concept of a combination of a coiled wire structure with a continuous V–shaped rib turbulator, which was referred to as a serrated wire coil (SWC). In the paper, the turbulent air flow behavior and heat transfer characteristics in a tube heat exchanger with SWC insert was investigated experimentally under isothermal–flux condition. Ambient air was used as a working fluid in a turbulent flow regime with Reynolds numbers (Re) ranging from 5114 to 14,752. The SWCs were inserted into test tubes with three different coil diameters (D_C) of 34.4, 41.2 and 47.9 mm (or diameter ratio, D_R = D_C/D_T = 0.68, 0.81 and 0.94) and four different pitch lengths (P_C) of 10, 20, 30 and 40 mm (or pitch ratio, P_R=P_C/D_T = 0.1969, 0.3937, 0.5906 and 0.7874). The experimental results of heat transfer and friction loss were presented as dimensionless parameters, Nusselt number (Nu) and friction factors (f), respectively. It was observed that the Nu increased with a decrease in pitch length and an increase in coil diameter. While the f decreased with an increase in both pitch length and coil diameter. Under the scope of this study, it was found that the insertion of the coils increased the Nu and f above the smooth tubes by approximately 1.75–2.46 times and 3.31–8.16 times, respectively. The empirical correlations of Nu and f for tubular heat exchanger inserted with SWC under the scope of this study were developed and showed error within ±4 % for Nu and ±12 % for f. The maximum thermal performance enhancement factor (η) for this work was about 1.41 for the SWC with D_C = 47.9 mm and P_C = 10 mm at Re = 5114. In addition, the Nu, f and η obtained in the optimal conditions of this work were compared with previous work.

线圈作为湍流发生器以增强热交换器中的传热的应用不断被研究和提出。在这项工作中，开发了一种新型线圈湍流器，其特征与先前提出的特征不同。它基于盘绕线结构与连续 V 形肋湍流器相结合的概念，称为锯齿线线圈 (SWC)。在本文中，在等温-通量条件下，通过实验研究了带有 SWC 插件的管式换热器中的湍流空气流动行为和传热特性。在雷诺数 (Re) 范围从 5114 到 14,752 的湍流流态中使用环境空气作为工作流体。将 SWC 插入具有三种不同线圈直径的试管中 ( D_C ) 为 34.4、41.2 和 47.9 毫米（或直径比，D _R  =  D _C / D _T  = 0.68、0.81 和 0.94）和四种不同的节距长度 ( P _C ) 为 10、20、30 和 40 毫米（或节距比率，P _R = P _C / D _T  = 0.1969、0.3937、0.5906 和 0.7874）。传热和摩擦损失的实验结果分别表示为无量纲参数、努塞尔数 ( Nu ) 和摩擦系数 ( f )。据观察，Nu随着节距的减少和线圈直径的增加而增加。而f随着节距长度和线圈直径的增加而减小。在本研究的范围内，发现线圈的插入使光滑管上方的Nu和f 分别增加了大约 1.75-2.46 倍和 3.31-8.16 倍。在本研究范围内开发了插入 SWC 的管式换热器的Nu和f的经验相关性，结果显示Nu误差在 ±4% 内，f误差在±12% 内。这项工作的最大热性能增强因子（η）约为1.41与SWC d _{C ^} = 47.9 mm 和P _C  = 10 mm，Re = 5114。此外，将在这项工作的最佳条件下获得的Nu、f和 η 与以前的工作进行了比较。