A Comparison of Coolant Options for Brayton Power Conversion Heat Rejection Systems

Siamidis, John; Mason, Lee S.

doi:10.1063/1.2169249

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…The bond between polymer matrix composite and foam was found to be approximately 72% along the length of one cross section while the bond between foam and titanium was found to be approximately 40% along the length of the cross section. Given that the bond is really an area rather than a line, the areal fraction of bond contact is (0.72) 2 and (0.40) 2 , respectively. Hence, the areal bond contact was estimated at 0.52 and 0.16, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…To accommodate the inevitability of micrometeoroid impacts, system design is driven toward the use of individual heat pipes, whereby a micrometeoroid impact on a given heat pipe removes only a small portion of the total cooling capability. [1][2] With this design philosophy in mind, development of heat rejection systems utilizing heat pipes is of ongoing interest.…”

Section: Introductionmentioning

confidence: 99%

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Heat Rejection Systems Utilizing Composites and Heat Pipes: Design and Performance Testing

Jaworske

Beach

Sanzi

2007

5th International Energy Conversion Engineering Conference and Exhibit (IECEC)

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Polymer matrix composites offer the promise of reducing the mass and increasing the performance of future heat rejection systems. With lifetimes for heat rejection systems reaching a decade or more in a micrometeoroid environment, use of multiple heat pipes for fault tolerant design is compelling. The combination of polymer matrix composites and heat pipes is of particular interest for heat rejection systems operating on the lunar surface. A technology development effort is under way to study the performance of two radiator demonstration units manufactured with different polymer matrix composite face sheet resin and bonding adhesives, along with different titanium-water heat pipe designs. Common to the two radiator demonstration units is the use of high thermal conductivity fibers in the face sheets and high thermal conductivity graphite saddles within a light weight aluminum honeycomb core. Testing of the radiator demonstration units included thermal vacuum exposure and thermal vacuum exposure with a simulated heat pipe failure. Steady state performance data were obtained at different operating temperatures to identify heat transfer and thermal resistance characteristics. Heat pipe failure was simulated by removing the input power from an individual heat pipe in order to identify the diminished performance characteristics of the entire panel after a micrometeoroid strike. Freeze-thaw performance was also of interest. This paper presents a summary of the two radiator demonstration units manufactured to support this technology development effort along with the thermal performance characteristics obtained to date. Future work will also be discussed. Nomenclature mm= millimeter m = meter T = temperature, K W = watts

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat Rejection Systems Utilizing Composites and Heat Pipes: Design and Performance Testing

Jaworske

Beach

Sanzi

2007

5th International Energy Conversion Engineering Conference and Exhibit (IECEC)

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“…NASA is interested in Brayton cycle converters for nuclear space power system (Siamidis, 2006;, Siamidis and Mason, 2006) A radiator is required to dissipate the waste heat generated during the thermal-to-electric conversion process. A pumped sodium-potassium (NaK) or water secondary loop is used to transfer waste heat from the power converters to the heat pipe radiator.…”

Section: Introductionmentioning

confidence: 99%

Intermediate Temperature Fluids Life Tests — Theory

Tarau

Sarraf²,

Locci

et al. 2007

AIP Conference Proceedings

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There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 750 K, including space nuclear power system radiators, and high temperature electronics cooling. Potential working fluids include organic fluids, elements, and halides, with halides being the least understood, with only a few life tests conducted. Potential envelope materials for halide working fluids include pure aluminum, aluminum alloys, commercially pure (CP) titanium, titanium alloys, and corrosion resistant superalloys. Life tests were conducted with three halides (AlBr 3 , SbBr 3 , and TiCl 4) and water in three different envelopes: two aluminum alloys (Al-5052, Al-6061) and CP-2 titanium. The AlBr 3 attacked the grain boundaries in the aluminum envelopes, and formed TiAl compounds in the titanium. The SbBr 3 was incompatible with the only envelope material that it was tested with, Al-6061. TiCl 4 and water were both compatible with CP2-titanium. A theoretical model was developed that uses electromotive force differences to predict the compatibility of halide working fluids with envelope materials. This theory predicts that iron, nickel, and molybdenum are good envelope materials, while aluminum and titanium halides are good working fluids. The model is in good agreement with results from previous life tests, as well as the current life tests.

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Mass optimization of a supercritical CO2 Brayton cycle with a direct cooled nuclear reactor for space surface power

Sondelski

Nellis

2019

Applied Thermal Engineering

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A Comparison of Coolant Options for Brayton Power Conversion Heat Rejection Systems

Cited by 7 publications

References 2 publications

Heat Rejection Systems Utilizing Composites and Heat Pipes: Design and Performance Testing

Heat Rejection Systems Utilizing Composites and Heat Pipes: Design and Performance Testing

Intermediate Temperature Fluids Life Tests — Theory

Mass optimization of a supercritical CO2 Brayton cycle with a direct cooled nuclear reactor for space surface power

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