Research Initiation: Heat Transfer and Pressure Drop in Tubes in the Transition Region for Various Entry Configurations

拟议研究项目的目的是研究 各种入口结构对局部传热和压力的影响 在过渡区的管道下降。 其中包括雷诺兹 数量从大约200到10，000，取决于进气道的类型 配置. 局部传热、压降和不透性 系数测量将在管道入口附近进行， 这些测量继续足够远的下游，完全- 实现了发展的层流或湍流， 相关性可能变得有效。 各种入口配置 会得到考验 将模拟管道入口附近的流动 使用现有的数值技术，并将结果进行比较 到实验研究。 压降的独立测量 在不加热的透明管和流动中的速度分布 可视化研究将被用来帮助建立流动模型 现象。 大量的数据和分析建模可用于 层流和全湍流管内流体流动过程 政权。 然而，很少有人研究这些问题 在包含雷诺数的过渡流态中， 大概有200到10000人 在实际工程设计中， 建议避免在这种制度下设计和操作; 然而，在设计限制下，这并不总是可行的。 多 此外，现有资料还涉及全面的- 远离入口或涉及入口效应的发展流 在高度理想化的入口下游 拟议的研究， 因此，将提供一个基本的了解和数据，在频谱 管流，也可以有重要的实际设计 应用程序导致改进的设计方法。

The objective of the proposed research project is to study the effects of various entry configurations on local heat transfer and pressure drop in tubes in the transition region. This includes Reynolds numbers from about 200 up to 10,000, depending on the type of inlet configuration. Local heat transfer, pressure drop, and intermittency factor measurements will be made near the entrance of a tube, with those measurements continuing far enough downstream that fully- developed laminar or turbulent flow is achieved and the usually cited correlations presumably become valid. Various entrance configurations will be tested. Flow near the entrance of the tube will be modeled using existing numerical techniques, and the results will be compared to the experimental study. Independent measurements of pressure drop and velocity profiles in unheated transparent tubes and flow visualization studies will be used to assist in modeling the flow phenomena. An enormous amount of data and analytical modeling is available for fluid flow processes in tubes in the laminar and fully-turbulent flow regimes. However, very little has been done to examine the problems in the transition flow regime encompassing Reynolds numbers from perhaps 200 to 10,000. In practical engineering design, the usual recommendation is to avoid design and operation in this regime; however, this is not always feasible under design constraints. Much of the information available furthermore deals with the fully- developed flows far from the entrance, or involves entrance effects downstream from highly idealized entrances. The proposed research, therefore, will provide a basic understanding and data in the spectrum of tube flows, and also could have important practical design applications leading to improved design methods.