研究了层流、过渡和湍流状态下环形螺旋强化内管内的流体流动。研究了三种不同类型的螺旋增强管——凹槽管、锯齿管和带肋管。通过可视化试验定性研究了流型和流型之间的转换。还对管表面的波峰和波谷进行了详细的温度剖面测量，以研究潜在的周向、轴向和螺旋变化。结果发现，凹槽内管在流动中引起了很大程度的涡流。 螺旋肋管和螺旋凹口管产生的涡流度逐渐减小。这些测试的结果被用来提出流动机制。主要结论是，流体并非仅在强化管壁附近的槽和顶部区域流动，也不是以远离管壁的纯轴向流动，而是以螺旋模式流动，在槽和顶部之间交替交叉。转换发生在RE310到1000范围之间。这些流动机制表明，特别是在层流和过渡流状态下，有可能大幅强化传热。 关键词:流体流动、螺旋换热器、扩展表面换热器、换热器、管道、湍流、流线流、雷诺数、测试、测量、温度分布、表面温度、实验、热流。引文:研讨会，ASHRAE交易1993，第99卷，pt。1.

Fluid flow in annuli spirally enhanced inner tubes was investigated for the laminar, transitional, and turbulent flow regimes. Three different types of spirally enhanced tubes were investigated - fluted, indented, and ribbed. Flow patterns and transitions between flow regimes were qualitatively investigated through visualisation tests. Detailed temperature profile measurements were also made on the crests and troughs of the tube surface to investigate potential circumferential, axial, and spiral variations. It was found that the fluted inner tubes induced a significant degree of swirl in the flow. Spirally ribbed and spirally indented tubes induced progressively smaller degrees of swirl. Results from these tests were used to propose flow mechanisms. The primary conclusion was that the fluid does not flow exclusively in trough and crest zones near the enhanced-tube wall and in a purely axial flow away from the wall but rather in a spiral pattern, alternately crossing over between the trough and the crest. Transition occurred between RE 310 to 1,000 range. These flow mechanisms indicate the potential for substantial heat transfer enhancement, especially in the laminar and transitional flow regimes.KEYWORDS: fluid flow, spiral heat exchangers, extended surface heat exchangers, heat exchangers, tubes, turbulent flow, streamline flow, Reynolds numbers, testing, measuring, temperature distribution, surface temperature, experiment, heat flow.