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Search Publications by: Ray Radebaugh (Assoc)

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Displaying 26 - 50 of 167

Verification of the Back-EMF Method for Piston Velocity Measurements

July 10, 2012
Author(s)
Ray Radebaugh, Michael A. Lewis, Peter E. Bradley
Linear compressors are used to drive pulse tube or Stirling cryocoolers, and they can be used as expanders in place of inertance tubes when inertance tubes cannot provide sufficient phase shifts between flow and pressure. Commercial linear compressors

DEMONSTRATION OF AN INTEGRATED MICRO CRYOGENIC COOLER AND MINIATURE COMPRESSOR FOR COOLING TO 200 K

November 17, 2011
Author(s)
Ryan J. Lewis, Mu Hong Lin, Yunda Wang, Jill Cooper, Peter E. Bradley, Ray Radebaugh, Marcia L. Huber, Yung-Cheng Lee
Joule-Thompson (J-T) based micro cryogenic coolers (MCCs) are attractive because they can provide the cryogenic temperatures needed for small electronic devices while having a low cost and small volumetric footprint. A compressor is a major part of a

Cryocoolers for Aircraft Superconducting Generators and Motors

June 13, 2011
Author(s)
Ray Radebaugh
The proposal by NASA to use high temperature superconducting (HTS) generators and motors on future (2035) aircraft for turboelectric propulsion imposes difficult requirements for cryocoolers. Net refrigeration powers of about 5 kW to 10 kW at 50 K to 65 K

Experiments with Linear Compressors for Phase Shifting in Pulse Tube Cryocoolers

June 13, 2011
Author(s)
Michael A. Lewis, Peter E. Bradley, Ray Radebaugh
For the past year NIST has been investigating the use of mechanical phase shifters as warm expanders for pulse tube cryocoolers. Unlike inertance tubes, which have a limited phase shifting ability at low acoustic powers, mechanical phase shifters have the

Micro Cryogenic Coolers for IR Imaging

April 29, 2011
Author(s)
Ryan J. Lewis, Yunda Wang, Jill Cooper, Mu Hong Lin, Victor M. Bright, Yung-Cheng Lee, Peter E. Bradley, Ray Radebaugh, Marcia L. Huber
Joule-Thomson micro cryogenic coolers (MCCs) are a preferred approach for small and low power cryocoolers. With the same heat lift, MCC's power input can be only 1/10 of a thermoelectric cooler's input, and MCC's size can be only 1/10 of a Stirling cooler

Model for Transient Behavior of Pulse Tube Cryocooler

January 1, 2011
Author(s)
Gershon Grossman, Peter E. Bradley, Michael A. Lewis, Ray Radebaugh
This article describes an investigation of the transient behavior of a small (2.0 W at 85 K) Pulse Tube cryocooler operating at 120 Hz with an average pressure of 3.5 MPa, capable of relatively fast cool-down to about 60 K. In a series of experiments, the

Effect of Component Geometry on Flow Nonuniformities in a Large Pulse Tube Cryocooler

May 17, 2010
Author(s)
Michael A. Lewis, Ryan P. Taylor, Ray Radebaugh, Peter E. Bradley
A single-stage pulse tube cryocooler was designed to achieve 50 W of refrigeration power at 50 K when driven by a pressure oscillator that can produce up to 2.8 kW of acoustic power at 60 Hz. Initial experimental data produced no-load temperatures that

Mixed Refrigerants for a Glass Capillary Micro Cryogenic Cooler

April 24, 2010
Author(s)
Mu Hong Lin, Peter E. Bradley, Marcia L. Huber, Ryan J. Lewis, Ray Radebaugh, Yung-Cheng Lee
Optimized mixed refrigerants are applied in Joule-Thomson (JT) micro cryogenic coolers (MCC) to enhance efficiency. Mixed refrigerants deliver equivalent refrigeration power with much lower pressure ratio and flow rate compared to pure nitrogen refrigerant