研究了用湍流促进的条形插入物强化或分割管内气体单相强迫对流换热。这项研究包括热工水力性能数据的实验测定、流动模式的可视化，以及通过分析手段解释强化传热的机理。为了获得热工水力数据，使用电加热流动设备将热空气输送至水冷钢管。测量管壁温度、流体体积温度和流速，得出四段管的截面平均传热系数。 空管的参考数据与通常的相关性一致。测试了一种弯曲带材插件的11种不同几何变化。雷诺数为10000时，传热系数增加185%至285%；然而，摩擦系数的相应增加为400%至1800%。对插入物入口区域进行了研究，以评估所需的插入物长度，以达到所开发的增强条件。给出了预测平均传热和压降的经验关联式。基于恒定压降和恒定泵送功率条件的性能评估研究表明，在特定雷诺数范围内，具有良好的强化比。 为了区分嵌件的墙和核心区域的效果，将一个嵌件分开，以提供单独测试的核心和墙嵌件。结果表明，插入件的核心区域是强化传热的主要部分。此外，还进行了流动可视化实验，这既有助于理解弯曲条插入物周围流动的物理性质，也有助于进一步了解增强机制。在切割刀片试验的基础上开发了另外两种刀片。它们被称为弯舌插入物，在压力损失小得多的情况下产生的增强效果稍低。 用于将其性能与其他插入件进行比较的性能评估标准表明，在低雷诺数下，其性能优于弯曲条插入件。最后，利用基本的表面更新/穿透理论，以合理的精度描述了带弯曲条插入件的管内强化传热的趋势。火管锅炉效率的整体提高不一定与插入式强化导致的气侧传热系数的增加成正比。有效使用插入增强功能需要整体系统设计，包括水侧系数。

The enhancement or segmentation of in-tube single-phase forced convective heat transfer in gases by using turbulence promoting bentstrip inserts was investigated. The study included experimental determination of thermal-hydraulic performance data, visualization of flow patterns, and interpretation of the mechanism of heat transfer enhancement by analytical means.To obtain thermal-hydraulic data, an electrically heated flow facility was used to deliver hot air to a water-cooled steel tube. Tube wall temperatures, fluid bulk temperatures, and flow rates were measured to derive sectional average heat transfer coefficients for four segments of the tube. Reference data for the empty tube were in agreement with the usual correlations. Eleven different geometrical variations of one type of bent-strip insert were tested. Increases in the heat-transfer coefficent of 185% to 285% were recorded at a Reynolds number of 10,000; however, accompanying increases in the friction factor were 400% to 1800%. A study of the insert entrance region was conducted in order to assess the insert length required for developed augmented conditions to be attained. Empirical correlations to predict average heat transfer and pressure drop are given.Performance evaluation studies based on constant pressure drop and constant pumping power conditions indicate that favorable enhancement ratios are available in specific Reynolds number ranges. To differentiate the effects of the wall and the core regions of an insert, one insert was cut apart to provide core and wall inserts, which were tested separately. The results indicate that the core region of the insert is responsible for the major portion of the heat transfer enhancement. Also conducted were flow visualization experiments, which provided both an understanding of the physical nature of the flow around the bent-strip inserts and further insight into the enhancement mechanisms.Two additional inserts were developed on the basis of the cut insert tests. Designated as bent-tab inserts, they produced somewhat lower enhancement at considerably less pressure loss. Performance evaluation criteria used to compare their performances with other inserts show improvement over the bent strip insert at low Reynolds numbers.Finally, basic surface-renewal/penetration theory was utilized to describe, with reasonable accuracy, the trends in heat transfer enhancement in tubes with bent-strip inserts.Overall improvement in fire-tube boiler efficiency is not necessarily in direct proportion to increases in gas-side heat transfer coefficients due to insert enhancement. Effective use of insert enhancement necessitates an overall system design including the water side coefficient.