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A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines. Phase III Final Report for the Radioisotope Power Conversion Technology NRAUnder Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity material. Also, the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator s low flow resistance; thus, the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) are included. The report also includes recommendations for further development of involute-foil regenerators from a higher-temperature material than nickel.
Document ID
Document Type
Contractor Report (CR)
Ibrahim, Mounir B.
(Cleveland State Univ. Cleveland, OH, United States)
Gedeon, David
(Gedeon Associates Athens, OH, United States)
Wood, Gary
(SunPower, Inc. Athens, OH, United States)
McLean, Jeffrey
(International Mezzo Technologies Baton Rouge, LA, United States)
Date Acquired
August 24, 2013
Publication Date
June 1, 2009
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
Funding Number(s)
WBS: WBS 138494.04.01.01
Distribution Limits
Public Use Permitted.
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