Early results from solar dynamic space power system testing

Shaltens, Richard K.; Mason, Lee S.

doi:10.2514/3.24113

Cited by 30 publications

(8 citation statements)

References 12 publications

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“…Slower yet (although there are exceptions), subsystem level thermal timescales tend to be the longest -ranging from seconds to hours. A Brayton solar-dynamic system thermal response to heat flux variation during a ground test simulating orbital operations 3 is captured in Fig. 10.…”

Section: B Transient 1 Analytical Formulationmentioning

confidence: 99%

Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems

Barrett

Johnson²

2005

3rd International Energy Conversion Engineering Conference

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Section: B Transient 1 Analytical Formulationmentioning

confidence: 99%

Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems

Barrett

Johnson²

2005

3rd International Energy Conversion Engineering Conference

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“…However, further tests are necessary to determine a more precise failing temperature and temperatures in this range were not investigated in this test program. The SD ground test demonstrator PLR which is coated with the alumina-titania coating, has been operated for over 365 hours in air (Shaltens, 1996b). Even at the maximum load (2kW) the heat generated by the PLR appears to be moderate (personnel could put their hands near it during operation (Shaltens, private communication), and there has been no observable degradation of the coating.…”

Section: And Discussionmentioning

confidence: 99%

Effects of ambient high temperature exposure on alumina-titania high emittance surfaces for solar dynamic systems

Groh¹,

Smith²,

Wheeler³

et al. 1999

AIP Conference Proceedings

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“…and (9) in which the integrationtakes place over the i th region and j th tube. On further de ning the dimensionless parameters…”

Section: Solar Heat Receiver Available Powermentioning

confidence: 99%

Thermal State-of-Charge of Space Solar Dynamic Heat Receivers

Hall

Glakpe

Cannon

et al. 2000

Journal of Propulsion and Power

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A theoretical framework is developed to determine the so-called thermal state-of-charge in solar heat receivers employing encapsulated phase change materials that undergo cyclic melting and freezing, and results are presented for the solar heat receiver component of NASA John H. Glenn Research Center at Lewis Field's Ground Test Demonstration System. The concepts of available power, virtual source temperature, and minimum gas available power are used as the bases for determining the state-of-charge. The state-of-charge is characterized in the subcooled, two-phase, and superheat regimes as well as startup, transition, and balanced-orbit modes. Baseline conjugate and primary state-of-charge curves are generated based on a priori known baseline system operating conditions through measurable parameters. Results indicate that for the baseline primary state-of-charge curve in balanced-orbit mode, there is a 33% energy margin (from the minimum state-of-charge line) at sunrise that indicates safe operation of the solar dynamic system; at sunset, the primary state-of-charge reaches 76%. Results for parametric changes indicate that the state-of-charge in the sensible regimes is completely reversed in the latent regime. NomenclatureA = area c = speci c heat of solid or liquid phase change material (PCM) c p = working uid speci c heat at constant pressure D ap = aperture diameter D cav = active cavity diameter F = geometric view factor h = enthalpy per unit mass h sf = PCM latent heat of fusion M = total number of axial nodes along tube or total PCM mass Çm = working uid mass ow rate N = total number of tubes in receiver P = working uid pressure Ç Q = heat transfer rate R = speci c gas constant Ç S gen = entropy generation rate Ste = modi ed Stefan number s, S = speci c, total entropy T = temperature T ap = effective aperture or virtual source temperature T m = PCM melt temperature T 0 = environmental dead state temperature t = time u, U = speci c, total internal energy V = total volume Ç W = rate of work transfer z = axial location Propulsion Of ce, Analysis and Management Branch. b 1 = rst conjugate state-of-charge (SOC) function b 2 = second conjugate SOC function c = ratio of speci c heats e = thermal capacitance ratio q = density r = Stefan-Boltzmann constant s cyc = total orbit period s off = eclipse period s on = sun period U = primary SOC function v j = j th tube mass fraction Subscripts ap = aperture av = average in = tube inlet losses = losses through shell and aperture max = maximum min = minimum out = tube outlet rcvr = receiver

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Early results from solar dynamic space power system testing

Abstract: A government/industryteam designed, built and tested a 2-kW e solar dynamic space power system in a large thermal/ vacuum facility with a simulated

Cited by 30 publications

References 12 publications

Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems

Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems

Effects of ambient high temperature exposure on alumina-titania high emittance surfaces for solar dynamic systems

Thermal State-of-Charge of Space Solar Dynamic Heat Receivers

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