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Accession Number N20120013822
Title Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB.
Publication Date Aug 2012
Media Count 22p
Personal Author X. Y. J. Wang
Abstract This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under 1) different sink temperatures and 2) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies.
Keywords Balance
Heat sources
Mathematical models
Radioisotope batteries
Steady state
Stirling cycle
Thermal energy
Thermoelectric generators

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 77C - Nuclear Auxiliary Power Systems
81I - Nuclear Propulsion
Corporate Author National Aeronautics and Space Administration, Cleveland, OH. NASA John H. Glenn Research Center at Lewis Field.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1305
Contract Number N/A

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