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Modelling, development and testing of a small-scale Collins type cryocooler.

Author(s) : HANNON C. L., KRASS B., GERSTMANN J., et al.

Summary

A multistage 10 K cryocooler is under development that is based upon a novel modification of the Collins cycle, a cycle commonly used in many large-scale high-efficiency cryogenic machines. This cryocooler design achieves its compactness and reliability by using microelectronics to enable complex valve timing in a mechanically simple yet efficient cold head design. This cycle is well suited to cryocoolers operating in a temperature range from 4 up to 30 K. The modular nature of this design enables the configuration of application specific two-stage (30 K), three-stage (10 K), and four-stage (4 K) cryocoolers. Design innovations include floating piston expanders and electromagnetic smart valves, which eliminate the need for mechanical linkages and reduce the input power, size, and weight of the cryocooler in an affordable modular design. A sophisticated LabView based control algorithm enables electronic control of the expansion cycle. Software based control enables variable valve timing and adaptive control logic. An engineering prototype has been built that integrates a floating piston expander and recuperative heat exchanger as a functional cryocooler stage. This prototype cryocooler stage has been tested in two configurations. Initial testing was as a balanced flow single stage cryocooler. The second configuration represented the third (lowest temperature) stage of a three-stage 10 K cryocooler. In this configuration, a precooling stream was added to the low temperature side of the heat exchanger to create the unbalanced flow condition that characterizes the Collins cycle. This paper reviews the engineering prototype design, the analytical modelling results, the prototype development testing, and the future development.

Details

  • Original title: Modelling, development and testing of a small-scale Collins type cryocooler.
  • Record ID : 2008-1050
  • Languages: English
  • Publication date: 2006/06/14
  • Source: Source: Proc. 14th int. Cryocooler Conf., Annapolis, MD
    477-485; fig.; phot.; 4 ref.

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