HIGH-TEMPERATURE SOLAR THERMIONIC GENERATORS. Third Quarterly Technical Report, November 1, 1963-January 31, 1964

Technical Report · Sat Feb 01 04:00:00 EST 1964

OSTI ID:4054085

A total of 2322 hours of continuous operation was recorded for thermionic converter #302 with no apparent degradation in output power. This converter is operating at an emitter temperature of 2000 deg K with a power output of 18.2 watts (0.7 V @ 26 amps). Converters #303 and #305 which were undergoing cyclic testing to simulate the 55 minute ON, 35 minute OFF orbital cycle operation, failed at 430 cycles (645 hours) and 624 cycles (936 hours) respectively. The metallographic analyses of these failed converters revealed significant limitations of the Series 300 converter when subjected to cyclic operation. Although many life-limiting features of the design were determined, it was concluded that the actual failures, which occurred at the seal metal-to- ceramic brazes, resulted from having overheated the seal structures during acceptance testing. Based on the evaluation of the test histories and failure analyses of converters #303 and #305, a modified converter design was prepared. The fabrication and acceptance test of three converters (Nos. 311, 312, and 313) was completed. Converter #312 is scheduled for continuous life evaluations while converters #311 and #313 will be cycle life evaluated. These converters are currentiy being installed in the VAC-ION Life Test Stand. The preliminary design of a solar thermionic generator was also completed during the past quarter and this design dictated the shape of the Series 310 converter emitter head to conform to a four converter generator cavity wall. The generator, with emitters operating at 2000 deg K, is rated at 66 watts @ 4.0 volts or 108 watts at 3.0 volts. The generator assembIy utilizes four Series 310 converters arranged symmetrically about the solar concentrator optical axis such that the emitters form a solar cavity receiver. The conftguration is such that any converter can be removed and replaced with a minimum of difficulty. The ground rules established prior to the initiation of the generator design calculation are presented. (auth)

• Research Organization: Thompson Ramo Wooldridge Inc. TRW Electromechanical Div., Cleveland
• NSA Number: NSA-18-016744
• OSTI ID: 4054085
• Report Number(s): TRW-ER-5802
• Country of Publication: United States
• Language: English

Related Subjects

BRAZING
CAVITIES
CERAMICS
CONFIGURATION
CONVERSION
EFFICIENCY
EMISSION
FABRICATION
FAILURES
GENERATORS
HEATING
HIGH TEMPERATURE
METALLOGRAPHY
METALS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
OPERATION
ORBITS
PHYSICS
PLANNING
POWER
PREPARATION
QUANTITATIVE ANALYSIS
SEALS
SUN
SUPERHEATING
SURFACES
TESTING
THERMIONICS