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SOME THERMODYNAMIC CONSIDERATIONS OF HELIUM TEMPERATURE CRYOCOOLERS.

Author(s) : DANEY D. E.

Summary

ATTEMPTS TO REACH LIQUID HELIUM TEMPERATURES WITH REGENERATIVE CRYOCOOLERS HAVE BEEN GENERALLY UNSUCCESSFUL. THE PRINCIPAL AND WELL KNOWN CAUSE OF THIS FAILURE IS THE DECAY OF THE REGENERATOR MATRIX HEAT CAPACITY AT LOW TEMPERATURE. AS THE REGENERATOR EFFECTIVENESS DECREASES, MOREAND MORE OF THE REFRIGERATION EFFECT GOES TO THE REGENERATOR LOSSES RATHER THAN TO THE LOAD. A LESS WELL-RECOGNIZED PROBLEM FOR SOME CRYOCOOLERS HAS BEEN OPERATION UNDER ADVERSE THERMODYNAMIC CONDITIONS. FOR EXAMPLE, OPERATION AT HIGH PRESSURE (4 MPA) CAN DECREASE THE CALCULATED EFFICIENCY OF THE LOWEST STAGE BY A FACTOR OF 10 OR MORE -PRIMARILY BECAUSE OF THE STRONGLY NEGATIVE JOULE-THOMSON EFFECT OF HELIUM AT LOW TEMPERATURE AND HIGH PRESSURE. THE A. FIRST INVESTIGATES THE EFFECT OF THE OPERATING REGIME ON THE EFFICIENCY OF HELIUM TEMPERATURE CRYOCOOLERS. NEXT, HE PROPOSES TWO SCHEMES OF HYBRID REGENERATIVE-COUNTER FLOW CRYOCOOLERS AS SOLUTIONS TO THE T CAPACITY. FINALLY, HE CALCULATES THE NET MASS FLOW THROUGH A TYPICAL HYBRID REGENERATOR-HEAT EXCHANGER FOR ONE OF THE SCHEMES PROPOSED.

Details

  • Original title: SOME THERMODYNAMIC CONSIDERATIONS OF HELIUM TEMPERATURE CRYOCOOLERS.
  • Record ID : 1982-0342
  • Languages: English
  • Publication date: 1980/10
  • Source: Source: NBS spec. Publ./Conf. NBS-IIF, Boulder
    n. 607; 48-56; 5 fig.; 2 tabl.; 8 ref.
  • Document available for consultation in the library of the IIR headquarters only.

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