CALCULATED REGENERATOR PERFORMANCE AT 4 K WITH HELIUM-4 AND HELIUM-3
- National Institute of Standards and Technology Boulder, Colorado, 80305 (United States)
The helium-4 working fluid in regenerative cryocoolers operating with the cold end near 4 K deviates considerably from an ideal gas. As a result, losses in the regenerator, given by the time-averaged enthalpy flux, are increased and are strong functions of the operating pressure and temperature. Helium-3, with its lower boiling point, behaves somewhat closer to an ideal gas in this low temperature range and can reduce the losses in 4 K regenerators. An analytical model is used to find the fluid properties that strongly influence the regenerator losses as well as the gross refrigeration power. The thermodynamic and transport properties of helium-3 were incorporated into the latest NIST regenerator numerical model, known as REGEN3.3, which was used to model regenerator performance with either helium-4 or helium-3. With this model we show how the use of helium-3 in place of helium-4 can improve the performance of 4 K regenerative cryocoolers. The effects of operating pressure, warm-end temperature, and frequency on regenerators with helium-4 and helium-3 are investigated and compared. The results are used to find optimum operating conditions. The frequency range investigated varies from 1 Hz to 30 Hz, with particular emphasis on higher frequencies.
- OSTI ID:
- 21136878
- Journal Information:
- AIP Conference Proceedings, Vol. 985, Issue 1; Conference: Cryogenic Engineering Conference - CEC: Advances in cryogenic engineering, Chattanooga, TN (United States), 16-20 Jul 2007; Other Information: DOI: 10.1063/1.2908551; (c) 2008 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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Related Subjects
GENERAL PHYSICS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BOILING POINTS
COMPUTERIZED SIMULATION
CRYOGENICS
ENTHALPY
HELIUM 3
HELIUM 4
PERFORMANCE
PRESSURE DEPENDENCE
R CODES
REFRIGERATION
SUPERCONDUCTING DEVICES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
WORKING FLUIDS