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High Reynolds Number Turbulence Research in Cryogenic Helium

低温氦中的高雷诺数湍流研究

基本信息

批准号：
1801780
负责人：
Wei Guo
金额：
$ 37.5万
依托单位：
Florida State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2021-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1801780&HistoricalAwards=false
关键词：
Reynolds Number Turbulence Research Cryogenic

项目摘要

Many flows in nature, including those generated by aircraft, ships, and the atmosphere, have extremely high Reynolds numbers. The Reynolds number is the ratio of flow's inertial forces relative to viscous forces, and it determines important flow properties such as turbulence. Understanding flows with extremely high Reynolds numbers will increase efficiency in practical vehicle applications and improve understanding of the climate. However, high Reynolds-number flow in conventional fluids like air and water occurs on a relatively large scale thus is difficult to study on the laboratory scale. Fortunately, high Reynolds number flows can be achieved using lower-density fluids such as cryogenic helium-4 in, for example, a small-scale laboratory pipe flow experiment. But to unlock the full potential of cryogenic helium-4, suitable flow measurement tools to quantify the turbulence are also required. The proposed research will therefore develop advanced molecular tagging velocity measurement techniques and apply the technique to high Reynolds number cryogenic helium pipe flow. In terms of educational opportunities, the joint College of Engineering operated by Florida State University and Florida A&M University will be leveraged to recruit under-represented minorities to participate in the project. The PI and the co-PI's groups will also contribute educational demonstrations for public open-house events at the National High Magnetic Field Laboratory and at the Florida Center for Advanced Aero-Propulsion.The scientific goal of this project is to develop a state-of-the-art molecular tagging velocimetry technique for cryogenic helium and to demonstrate its usefulness by applying it in the study of high Reynolds number cryogenic helium pipe flow. Sophisticated patterns of the molecular tracer lines will be created by splitting and focusing a femtosecond laser beam in liquid helium. Advanced pattern-tracking algorithms will be incorporated, and the spatial and temporal resolutions of the tracer imaging process will be optimized. These developments will unlock the full potential of cryogenic helium in turbulence research and model testing. The planned study on high Reynolds number pipe flows in helium will allow an independent examination of the near-wall velocity field and the associated von K?rm?n coefficient, which may help resolve existing controversies regarding the universality of this coefficient. Also, new knowledge about the near-wall spatial velocity correlations will be produced by tracking the tracer lines created perpendicular to the wall. Furthermore, by measuring the pressure drop along the pipe, reliable friction factor data for high Reynolds number flows will be obtained, which will benefit the design of various engineering systems that exhibit high Reynolds numbers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

自然界中的许多流动，包括由飞机、船舶和大气产生的流动，都具有极高的雷诺数。雷诺数是流体惯性力与粘性力的比值，它决定了湍流等重要的流动特性。了解具有极高雷诺数的流动将提高实际车辆应用的效率，并改善对气候的理解。然而，在常规流体（如空气和水）中的高雷诺数流动发生在相对大的规模上，因此难以在实验室规模上进行研究。幸运的是，高雷诺数流动可以使用较低密度的流体，如低温氦-4，例如，在小规模的实验室管流实验。但是，为了释放低温氦-4的全部潜力，还需要合适的流量测量工具来量化湍流。因此，拟议的研究将开发先进的分子标记速度测量技术，并将该技术应用于高雷诺数低温氦管流。在教育机会方面，将利用佛罗里达州立大学和佛罗里达A M大学联合开办的工程学院，招收代表性不足的少数族裔参与该项目。PI和co-PI的小组还将在国家强磁场实验室和佛罗里达先进航空推进中心为公众开放活动提供教育演示。该项目的科学目标是开发一种用于低温氦的最先进的分子标记测速技术，并通过将其应用于高雷诺数低温氦管流的研究来证明其实用性。分子示踪线的复杂图案将通过在液氦中分裂和聚焦飞秒激光束来创建。将采用先进的模式跟踪算法，并优化示踪剂成像过程的空间和时间分辨率。这些发展将释放低温氦在湍流研究和模型测试中的全部潜力。高雷诺数的氦气管流的计划研究将允许一个独立的检查近壁速度场和相关的冯K？rm？n系数，这可能有助于解决关于这一系数的普遍性的现有争议。此外，通过跟踪垂直于壁创建的示踪线，将产生关于近壁空间速度相关性的新知识。此外，通过测量沿管道的沿着压降，将获得高雷诺数流动的可靠摩擦系数数据，这将有利于各种高雷诺数工程系统的设计。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

A cryogenic-helium pipe flow facility with unique double-line molecular tagging velocimetry capability

具有独特双线分子标记测速能力的低温氦管流设施

DOI：
10.1063/5.0008117
发表时间：
2020
期刊：
Review of Scientific Instruments
影响因子：
1.6
作者：
Sanavandi, Hamid;Bao, Shiran;Zhang, Yang;Keijzer, Ruben;Guo, Wei;Cattafesta, III, Louis N.
通讯作者：
Cattafesta, III, Louis N.

Molecular Tagging Velocimetry in Superfluid Helium-4: Progress, Issues, and Future Development

超流 Helium-4 中的分子标记测速：进展、问题和未来发展