Visualizing Heat Transport in Helium II
- National High Magnetic Field Laboratory, Mechanical Engineering Department, Florida State University, Tallahassee, FL 32310 (United States)
Many technical systems including large particle accelerators, space astrophysics experiments and high field superconducting magnets are enabled at least in part by the unique transport properties of He II. Heat is carried in He II by a mechanism known as thermal counterflow whereby the liquid behaves as if it consists of two fluid components, with the normal fluid component carrying the entropy and the superfluid component flowing in opposition to conserve mass and momentum. This unique mechanism leads to an effective thermal conductivity for He II which is many orders of magnitude larger than that of classical fluids or even metals at low temperature. Although scientists have long believed in the theory of thermal counterflow, there have been very few attempts to actually observe this process and the associated fluid component motion. Recently, our group has been able to utilize the Particle Image Velocimetry (PIV) technique to study the local dynamics of He II thermal counterflow. Some exceptional observations have resulted from this work. Following a brief motivational introduction, the paper begins with a review of the important heat transport mechanisms in He II. Next the challenges and techniques available for visualizing counterflow fields in He II are described. Finally, recent PIV experiments on He II heat transport that clearly display the flow fields associated with motion of the two fluid components are discussed.
- OSTI ID:
- 20800207
- Journal Information:
- AIP Conference Proceedings, Vol. 823, Issue 1; Conference: Cryogenic engineering conference, Keystone, CO (United States), 29 Aug - 2 Sep 2005; Other Information: DOI: 10.1063/1.2202592; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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