NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Life and Reliability Characteristics of TurboBrayton CoolersWear and internal contaminants are two of the primary factors that influence reliable, long-life operation of turbo-Brayton cryocoolers. This paper describes tests that have been conducted and methods that have been developed for turbo-Brayton components and systems to assure reliable operation. The turbomachines used in these coolers employ self-acting gas bearings to support the miniature high-speed shafts, thus providing vibration-free operation. Because the bearings are self-acting, rubbing contact occurs during initial start-up and shutdown of the machines. Bearings and shafts are designed to endure multiple stop/start cycles without producing particles or surface features that would impair the proper operation of the machines. Test results are presented for a variety of turbomachines used in these systems. The tests document extended operating life and start/stop cycling behavior for machines over a range of time and temperature scales. Contaminants such as moisture and other residual gas impurities can be a source of degraded operation if they freeze out in sufficient quantities to block flow passages or if they mechanically affect the operation of the machines. A post-fabrication bakeout procedure has been successfully used to reduce residual internal contamination to acceptable levels in a closed cycle system. The process was developed during space qualification tests on the NICMOS cryocooler. Moisture levels were sampled over a six-month time interval confirming the effectiveness of the technique. A description of the bakeout procedure is presented.
Document ID
20000097959
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Breedlove, Jeff J.
(Creare, Inc. Hanover, NH United States)
Zagarola, Mark
(Creare, Inc. Hanover, NH United States)
Nellis, Greg
(Creare, Inc. Hanover, NH United States)
Dolan, Frank
(Creare, Inc. Hanover, NH United States)
Swift, Walt
(Creare, Inc. Hanover, NH United States)
Gibbon, Judith
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Obenschain, Arthur F.
Date Acquired
August 19, 2013
Publication Date
January 1, 2000
Subject Category
Engineering (General)
Meeting Information
Meeting: 11th International Cryocooler Conference
Location: CO
Country: United States
Start Date: June 1, 2000
Funding Number(s)
CONTRACT_GRANT: NAS5-31281
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available