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。 雷诺数是流动惯性力与粘性力的比值，它决定了重要的流动特性，例如湍流。 了解极高雷诺数的流动将提高实际车辆应用的效率并增进对气候的了解。 然而，空气和水等常规流体中的高雷诺数流动发生在相对较大的范围内，因此很难在实验室规模上进行研究。幸运的是，在小型实验室管道流实验中，可以使用低温氦 4 等较低密度流体来实现高雷诺数流。但为了充分发挥低温氦 4 的潜力，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农工大学联合运营的工程学院来招募代表性不足的少数族裔参与该项目。 PI 和联合 PI 的小组还将为国家高磁场实验室和佛罗里达州先进航空推进中心的公共开放活动提供教育演示。该项目的科学目标是开发一种先进的-最先进的低温氦分子标记测速技术，并通过将其应用于高雷诺数低温氦管流研究来证明其有用性。通过在液氦中分裂和聚焦飞秒激光束，可以创建复杂的分子示踪线图案。将纳入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。这些进展将释放低温氦在湍流研究和模型测试中的全部潜力。计划中的氦气高雷诺数管流研究将允许对近壁速度场和相关的 von Körmön 系数进行独立检查，这可能有助于解决有关该系数普遍性的现有争议。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，可以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，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来获得支持。

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: 2020-05
• 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: 2018-12
• 期刊: Journal of Low Temperature Physics
• 影响因子: 2
• 作者: Guo; Wei
• 通讯作者: Wei

A magnetic levitation based low-gravity simulator with an unprecedented large functional volume

具有前所未有的大功能体积的磁悬浮低重力模拟器

• DOI: 10.1038/s41526-021-00174-4
• 发表时间: 2021-10-29
• 期刊: NPJ Microgravity
• 影响因子: 5.1
• 作者: Sanavandi H;Guo W
• 通讯作者: Guo W