High Reynolds Number Turbulence Research in Cryogenic Helium

低温氦中的高雷诺数湍流研究

• 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

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，包括飞机，船只和气氛产生的流量，雷诺数很高。 雷诺数是流动力相对于粘性力的惯性力之比，它决定了重要的流量特性，例如湍流。 使用极高的雷诺数字了解流量将提高实际车辆应用的效率并提高对气候的理解。 然而，在较大的规模上发生的传统流体中的雷诺数很高，因此很难在实验室尺度上研究。幸运的是，可以使用低密度流体（例如低温氦4 in），例如小型实验室管道流量实验来实现高雷诺数流。但是，为了解锁低温氦4的全部潜力，还需要量化湍流的合适流量测量工具。因此，拟议的研究将开发高级分子标记速度测量技术，并将技术应用于高雷诺数高温氦气流。在教育机会方面，佛罗里达州立大学和佛罗里达州立大学A＆M大学经营的工程联合学院将被利用以招募人数不足的少数民族参加该项目。 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.分子示踪系的复杂图案将通过在液态氦中分裂和聚焦为飞秒激光束来创建。将合并高级模式跟踪算法，并将优化示踪剂成像过程的空间和时间分辨率。这些发展将在湍流研究和模型测试中释放低温氦气的全部潜力。对氦气中高雷诺数管流的计划研究将允许对近壁速度场和相关的von k？rm？n系数进行独立检查，这可能有助于解决有关该系数的普遍性的现有争议。同样，通过跟踪垂直于壁的示踪线来产生有关近壁空间速度相关性的新知识。此外，通过测量沿管道的压降，将获得高雷诺数数量流的可靠摩擦因子数据，这将有益于表现出高雷诺数字的各种工程系统的设计。该奖项反映了NSF的法定任务，并通过使用该基金会的知识优点和广泛影响来评估，这是NSF的法定任务。

项目成果

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

• DOI: 10.1007/s10909-018-2102-1
• 发表时间: 2018
• 期刊: Journal of Low Temperature Physics
• 影响因子: 2
• 作者: Guo, Wei