SP-100 advanced radiator designs for thermoelectric and Stirling applications

Moriarty, Michael P.; Determan, W.R.

doi:10.1109/iecec.1989.74628

Cited by 4 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Carbon-carbon fiber material is also being considered for heat pipe structures. 38 Advantages of heat pipe technology include proven low specific mass heat transfer technology, high temperature operation and substantial heat rejection capability, high survivability (segmentation means puncture of an isolated heat pipe will not result in much loss of capability), and the ability for self starting with no moving parts. Limitations may include capillary force limits, viscous drag and sonic flow limits, entrainment of liquid in the flowing gas stream, and boiling rate limits.…”

Section: Heat Rejectionmentioning

confidence: 99%

Multi Megawatt Power System Analysis Report

Longhurst¹,

Harvego²,

Schnitzler³

et al. 2001

View full text Add to dashboard Cite

Missions to the outer planets or to near-by planets requiring short times and/or increased payload carrying capability will benefit from nuclear power. A concept study was undertaken to evaluate options for a multi-megawatt power source for nuclear electric propulsion. The nominal electric power requirement was set at 15 MW e with an assumed mission profile of 120 days at full power, 60 days in hot standby, and another 120 days of full power, repeated several times for 7 years of service. Of the numerous options considered, two that appeared to have the greatest promise were a gas-cooled reactor based on the NERVA Derivative design, operating a closed cycle Brayton power conversion system; and a molten lithium-cooled reactor based on SP-100 technology, driving a boiling potassium Rankine power conversion system. This study examined the relative merits of these two systems, seeking to optimize the specific mass. Conclusions were that either concept appeared capable of approaching the specific mass goal of 3-5 kg/kW e estimated to be needed for this class of mission, though neither could be realized without substantial development in reactor fuels technology, thermal radiator mass efficiency, and power conversion and distribution electronics and systems capable of operating at high temperatures. Though the gas-Brayton systems showed an apparent advantage in specific mass, differences in the degree of conservatism inherent in the models used suggests expectations for the two approaches may be similar. Brayton systems eliminate the need to deal with two-phase flows in the microgravity environment of space.iii CONTENTS

show abstract

Section: Heat Rejectionmentioning

confidence: 99%

Multi Megawatt Power System Analysis Report

Longhurst¹,

Harvego²,

Schnitzler³

et al. 2001

View full text Add to dashboard Cite

show abstract

“…Because of their redundant and reliable operation and efficient spreading and rejection of the waste heat, heat pipes could markedly reduce the mass of the radiator. The choices of the working fluid and the design and operation temperature of the radiator heat pipes determine their performance and hence, the specific mass of the radiator (Moriarty and Determan, 1989;Rovang et al, 1991). For radiator temperatures of 350 K to 800 K, the present choices of working fluids with increasing temperature are water, cesium, rubidium, and potassium.…”

Section: Introductionmentioning

confidence: 99%

Radiator Heat Pipes with Carbon-Carbon Fins and Armor for Space Nuclear Reactor Power Systems

Tournier¹,

El‐Genk²

2005

AIP Conference Proceedings

View full text Add to dashboard Cite

Technologies for Space Reactor Power Systems are being developed to enable future NASA's missions early next decade to explore the farthest planets in the solar system. The choices of the energy conversion technology for these power systems require radiator temperatures that span a wide range, from 350 K to 800 K. Heat pipes with carbon-carbon fins and armor are the preferred choice for these radiators because of inherent redundancy and efficient spreading and rejection of waste heat into space at a relatively small mass penalty. The performance results and specific masses of radiator heat pipes with cesium, rubidium, and potassium working fluids are presented and compared in this paper. The heat pipes operate at 40% of the prevailing operation limit (a design margin of 60%), typically the sonic and/or capillary limit. The thickness of the carbon-carbon fins is 0.5 mm but the width is varied, and the evaporator and condenser sections are 0.15 and 1.35 m long, respectively. The 400-mesh wick and the heat pipe thin metal wall are titanium, and the carbon-carbon armor (~ 2 mm-thick) provides both structural strength and protection against meteoroids impacts. The cross-section area of the Dshaped radiator heat pipes is optimized for minimum mass. Because of the low vapor pressure of potassium and its very high Figure-Of-Merit (FOM), radiator potassium heat pipes are the best performers at temperatures above 800 K, where the sonic limit is no longer an issue. On the other hand, rubidium heat pipes are limited by the sonic limit below 762 K and by the capillary limit at higher temperature. The transition temperature between these two limits for the cesium heat pipes occurs at a lower temperature of 724 K, since cesium has lower FOM than rubidium. The present results show that with a design margin of 60%, the cesium heat pipes radiator is best at 680-720 K, the rubidium heat pipes radiator is best at 720-800 K, while the potassium heat pipes radiator is the best performer and lightest at higher temperatures > 800 K.

show abstract

“…A number of space reactor power system concepts have been developed or proposed with liquidmetal heat pipes for the passive and redundant removal and transport of the fission power generated in the reactor to the energy conversion subsystem (Angelo and Buden, 1985;El-Genk, 1994 and2008b;Ranken, 1982 andDeterman and Hagelston, 1992;, Poston et al, 2002;Ring et al, 2003; These heat pipes have also been considered for transporting waste heat from the energy conversion subsystems, and redundant and enhanced performance of heat rejection radiators. Energy conversion options considered for uses in space reactor power systems include Free-Piston Stirling Engine, FPSE (e.g., Angelo and Buden, 1985;Moriarty and Determan, 1989;Schreiber, 2001;Thieme et al, 2002 and2004;Schmitz et al, 1994 and2005), Thermoelectric (e.g., Ranken, 1982;Moriarty and Determan, 1989;Josloff et al, 1994;Marriott and Fujita, 1994;Caillat et al, 2000;Saber, 2003 and2005;Tournier, 2006b, El-Genk, 2008), Closed Brayton Cycle (CBC) with rotating turbo-machines (e.g., Harty and Mason, 1993;Shepard et al, 1994;Barrett and Reid, 2004;Barrett and Johnson, 2005;Gallo and El-Genk, 2009;El-Genk et al 2010;El-Genk, 1994 and2008), Potassium Rankine cycle (Angelo and Buden, 1985;Yoder and Graves, 1985;Bevard and Yoder, 2003), Thermionic (e.g., El-Genk and Paramonov, 1999;Ranken, 1990;…”

Section: Introductionmentioning

confidence: 99%

“…In these power systems, liquid-metal and water heat pipes have also been proposed for the heat rejection radiator panels, depending on the heat rejection temperature (e.g., Ranken, 1982;Angelo and Buden, 1985;El-Genk, Buksa and Seo, 1988;Moriarty and Determan, 1989;Gunther, 1990;Trujillo et al, 1990;Rovang et al, 1991;Harty and Mason, 1993;Marriott and Fujita, 1994;Josloff et al, 1994;Juhasz and Rovang, 1995;Tournier, 2004a and2006a;Schmitz et al, 2005;Tournier and El-Genk, 2006).…”

Section: Introductionmentioning

confidence: 99%

Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

El‐Genk¹,

Tournier²

2011

Frontiers in Heat Pipes

View full text Add to dashboard Cite

Water and liquid-metal heat pipes are considered for redundant and passive cooling of nuclear reactors and redundant operation of light-weight heat rejection radiators of space reactor power systems. The systems operate continuously for many years independent of the Sun, are enabling of deep space exploration and could provide 10's of kilowatts of electrical power for lunar and Martian outposts. Space reactors typically operate at 900 K -1400 K could be cooled using liquid-metal heat pipes with either sodium (900 -1100 K) or lithium (1100 K-1400 K) working fluids. The heat rejection temperatures dictate the working fluid of the radiator heat pipes; potassium for 600 -800 K, rubidium for 500 -700 K, and water for < 500 K. These working fluids would be frozen prior to starting up the power systems in orbit or at destination. The startup of water and liquid-metal heat pipes from a frozen state is complex, involving a number of non-linear mass and heat transport processes that require implementing appropriate procedures, depending on the type of working fluid. This paper reviews operation and design constraints pertinent to the uses of water and liquidmetal heat pipes in space reactor systems, and the modeling capabilities of the startup from a frozen state. In addition to models validation, results of design optimization of liquid-metal and water heat pipes in a number of space reactor power systems are presented and discussed.

show abstract

SP-100 advanced radiator designs for thermoelectric and Stirling applications

Cited by 4 publications

References 0 publications

Multi Megawatt Power System Analysis Report

Multi Megawatt Power System Analysis Report

Radiator Heat Pipes with Carbon-Carbon Fins and Armor for Space Nuclear Reactor Power Systems

Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

Contact Info

Product

Resources

About