Numerical simulation is performed to evaluate the privilege of inserting stationary or rotating twisted tape inside a tube as a heat transfer enhancement technique. The main emphasis of this work is placed on understanding the effect of pitch distance on the hydrothermal performance of such a system. The obtained results are validated with published experimental findings. The results of numerical study shows that the heat transfer, pressure drop and total energy consumption are increased by inserting a twisted tape inside a tube. Under the stationary condition, decreasing the pitch distance results in higher Nusselt number together with more friction factor. As the twisted tape starts to rotate (RTT1 case), both Nusselt number and friction factor are further increased. However, decreasing the pitch distance from L/2 to L/6 exhibits a marginal impact on the Nusselt number and friction factor. Further increase in the angular velocity (RTT3 case), although improved the average Nusselt number, comes at the expense of much more friction factor as well as energy consumption. Considering performance evaluation criterion (PEC) as a metric to assess the interaction between heat transfer and energy consumption, it is found that rotating twisted tape is beneficial at lower Reynolds number. Among the design parameters analysed in this research, the highest PEC number of 1.5 corresponds to the case of stationary twisted tape at Reynolds number of 1000 and twisted tape pitch of L/6.

进行数值模拟以评估在管内插入固定或旋转扭曲带作为传热增强技术的优势。这项工作的主要重点是了解间距对这种系统的水热性能的影响。获得的结果与已发表的实验结果进行了验证。数值研究结果表明，在管内插入扭绞带可增加传热、压降和总能耗。在静止条件下，减小节距会导致更高的努塞尔数和更多的摩擦系数。随着扭带开始旋转（RTT1 案例），努塞尔数和摩擦系数进一步增加。然而，将节距从 L/2 减小到 L/6 对努塞尔数和摩擦系数的影响很小。角速度的进一步增加（RTT3 情况）虽然提高了平均努塞尔数，但代价是摩擦系数和能量消耗更多。将性能评估标准 (PEC) 作为评估传热和能耗之间相互作用的指标，发现旋转双绞带在较低雷诺数下是有益的。在本研究分析的设计参数中，最高 PEC 数为 1.5，对应于雷诺数为 1000 且绞带节距为 L/6 的固定绞带的情况。以牺牲更多的摩擦系数和能源消耗为代价。将性能评估标准 (PEC) 作为评估传热和能耗之间相互作用的指标，发现旋转双绞带在较低雷诺数下是有益的。在本研究分析的设计参数中，最高 PEC 数为 1.5，对应于雷诺数为 1000 且绞带节距为 L/6 的固定绞带的情况。以牺牲更多的摩擦系数和能源消耗为代价。将性能评估标准 (PEC) 作为评估传热和能耗之间相互作用的指标，发现旋转双绞带在较低雷诺数下是有益的。在本研究分析的设计参数中，最高 PEC 数为 1.5，对应于雷诺数为 1000 且绞带节距为 L/6 的固定绞带的情况。