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Ultimate Temperature of Pulse Tube CryocoolersAn ideal pulse tube cryocooler using an ideal gas can operate at any temperature. This is not true for real gases. The enthalpy flow resulting from the real gas effects of 3He, 4He, and their mixtures in ideal pulse tube cryocoolers puts limits on the operating temperature of pulse tube cryocoolers. The discussion of these effects follows a previous description of the real gas effects in ideal pulse tube cryocoolers and makes use of models of the thermophysical properties of 3He and 4He. Published data is used to extend the analysis to mixtures of 3He and 4He. The analysis was done for pressures below 2 MPa and temperatures below 2.5 K. Both gases and their mixtures show low temperature limits for pulse tube cryocoolers. These limits are in the 0.5-2.2 K range and depend on pressure and mixture. In some circumstances, even lower temperatures may be possible. Pulse tube cryocoolers using the ha-fluid properties of dilute 3He in superfluid 4He appear to have no limit.
Document ID
20110009872
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Kittel, Peter (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 25, 2013
Publication Date
June 26, 2009
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
ARC-E-DAA-TN505
Meeting Information
Meeting: Cryogenic Engineering Conference
Location: Tucson, AZ
Country: United States
Start Date: June 28, 2009
End Date: July 2, 2009
Funding Number(s)
CONTRACT_GRANT: NAS2-03144
Distribution Limits
Public
Copyright
Public Use Permitted.

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