Sanavandi Hamid, Bao Shiran, Zhang Yang, Keijzer Ruben, Guo Wei, Cattafesta Louis N
Department of Mechanical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida 32310, USA.
National High Magnetic Field Laboratory, Florida State University, 1800 E Paul Dirac Dr., Tallahassee, Florida 32310, USA.
Rev Sci Instrum. 2020 May 1;91(5):053901. doi: 10.1063/5.0008117.
Cryogenic helium-4 has extremely small kinetic viscosity, which makes it a promising material for high Reynolds (Re) number turbulence research in compact laboratory apparatus. In its superfluid phase (He II), helium has an extraordinary heat transfer capability and has been utilized in various scientific and engineering applications. In order to unlock the full potential of helium in turbulence research and to improve our understanding of the heat transfer mechanism in He II, a flow facility that allows quantitative study of helium heat-and-mass transfer processes is needed. Here, we report our work in assembling and testing a unique helium pipe-flow facility that incorporates a novel double-line molecular tagging velocimetry (DL-MTV) system. This flow facility allows us to generate turbulent pipe flows with Re above 107, and it can also be adapted to produce heat-induced counterflow in He II. The DL-MTV system, which is based on the generation and tracking of two parallel thin He molecular tracer lines with an adjustable separation distance, allows us to measure not only the velocity profile but also both the transverse and longitudinal spatial velocity structure functions. We have also installed a differential pressure sensor on the flow pipe for pressure drop measurements. The testing results of the flow facility and the measuring instruments are presented. We discuss how this facility will allow us to solve some outstanding problems in the helium heat-and-mass transfer topic area.
低温氦 - 4具有极小的运动粘度，这使其成为在紧凑实验室设备中进行高雷诺数（Re）湍流研究的理想材料。在其超流相（He II）中，氦具有非凡的传热能力，并已应用于各种科学和工程领域。为了充分发挥氦在湍流研究中的潜力，并增进我们对He II中传热机制的理解，需要一种能够对氦的热质传递过程进行定量研究的流动装置。在此，我们报告了我们在组装和测试一种独特的氦管流装置方面的工作，该装置集成了一种新型的双线分子标记测速（DL - MTV）系统。这种流动装置使我们能够产生Re大于107的湍流管流，并且还可以进行调整以在He II中产生热致逆流。DL - MTV系统基于两条平行的、具有可调节间距的细氦分子示踪线的生成和跟踪，不仅使我们能够测量速度剖面，还能测量横向和纵向的空间速度结构函数。我们还在流管上安装了一个压差传感器用于压降测量。本文给出了流动装置和测量仪器的测试结果。我们讨论了该装置将如何帮助我们解决氦热质传递领域中的一些突出问题。
