In this experimental study, the influence of combined passive technique on heat transfer, friction factor, and thermal performance factor are investigated in a double pipe heat exchanger fitted with different turbulators and GO-Water nanofluid. Experiments were conducted for a fixed flow rate of (Re = 2500) in the inner tube (hot fluid); for varying flow rates (500 ≤ Re ≤ 5000) and volume concentrations (0.05%–0.15%) of GO-Water nanofluid in the outer tube (cold fluid), under uniform heat flux condition, using i) circular finned twisted tape inserts with TR = 20, 13.3 and 9.8 ii) frequently spaced helically twisted inserts with the number of helices = 5, 7, 9). The experimental results showed that the Nusselt number and Thermal Performance Factor (TPF) were increased with decreased twist ratio and increased helices and volume concentration of nanofluid. The enhancement of heat transfer was 21.35% and 22.21%, respectively, whereas the enhancement in the Thermal Performance Factor (TPF) was 7.16% and 8.06%, respectively, for the above two test conditions. The augmentation was maximum for configurations corresponding to the circular finned twisted tape insert with TR = 9.8 and frequently spaced helical screw-tape with 9 helices in 0.15% volume concentrations of GO-water nanofluid as compared to other combinations, with a slight penalty in pressure drop.

在本实验研究中，在装有不同湍流器和GO-Water纳米流体的双管热交换器中，研究了组合被动技术对传热，摩擦系数和热性能系数的影响。对内管（热流体）中的固定流速（Re = 2500）进行了实验；在均匀的热通量条件下，通过以下方式在外管（冷流体）中使用不同流量（500≤Re≤5000）和GO-水纳米流体的体积浓度（0.05％–0.15％），使用TR = 20、13.3和9.8 ii）螺旋间距为5、7、9）的经常间隔的螺旋扭曲刀片。实验结果表明，随着扭转比的降低，纳米流体螺旋和体积浓度的增加，Nusselt数和热性能因子（TPF）均增加。在以上两个测试条件下，热传递的增强分别为21.35％和22.21％，而热性能因子（TPF）的增强分别为7.16％和8.06％。与其他组合相比，对应于TR = 9.8的圆形翅片加捻的带状插入件和带有0.1％体积浓度的GO-水纳米流体的9个螺旋的频繁间隔螺旋螺旋胶带的配置，增加量最大。下降。以上两个测试条件分别为06％。与其他组合相比，对应于TR = 9.8的圆形翅片加捻的带状插入件和带有0.1％体积浓度的GO-水纳米流体的9个螺旋的频繁间隔螺旋螺旋胶带的配置，增加量最大。下降。以上两个测试条件分别为06％。与其他组合相比，对应于TR = 9.8的圆形翅片加捻的带状插入件和带有0.1％体积浓度的GO-水纳米流体的9个螺旋的频繁间隔螺旋螺旋胶带的配置，增加量最大。下降。