Parametric analyses of AMTEC multitube cells and recommendation for revised cell design

Schock, Alfred; Noravian, H.; Or, C.; Kumar, V.

doi:10.1063/1.51954

Cited by 20 publications

(3 citation statements)

References 3 publications

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“…Because the current density and BASE temperature distributions are known, the local sodium vapor mass flow rate can be calculated by integrating Eq. (6). Therefore, all terms on the right-hand-side (RHS) of Eq.…”

Section: Pressure Drop Along the Base Tubesmentioning

confidence: 98%

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Sodium Vapor Pressure Losses in a Multitube, Alkali-Metal Thermal-to-Electric Converter

Tournier

El‐Genk

1999

Journal of Thermophysics and Heat Transfer

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A model was developed to calculate the vapor pressure losses and characterize the vapor flow regimes on the cathode side of a multitube, vapor-anode, alkali-metal thermal-to-electric converter (AMTEC) cell, with internal chevron's radiation shields. The dusty gas model was used to predict the vapor flow over a wide range of pressures, including the free-molecular, transition, and continuum flow regimes. Results showed that the vapor flow on the cathode side of a multitube AMTEC cell is typically in the transition regime, and that the pressure loss in the chevron's shield accounts for about 50% of the total pressure losses. An analysis is also performed to optimize the conical chevron's geometry for minimum pressure loss. Nomenclature A= surface area, m 2 a cc = accommodation coefficient, Eqs. (1) and (25), 1 b = perpendicular distance between chevrons, m D = flow diffusion coefficient, m 2 /s D a = diameter of centerline liquid-return artery, m, 3.18 mm D B = BASE tubes outer diameter, m, 6.35 mm D e = equivalent hydraulic diameter, m D w = inner diameter of AMTEC cell wall, m, 33.2 mm d = separation distance between chevrons, m F = Faraday's constant, 96,485 C/mol / = laminar friction coefficient G -dimensionless geometric factor for pressure loss, Eq. (5) / = total cell electrical current, A J r = electrode current density, A/m 2 Kn -Knudsen number of sodium vapor L = effective flow path through chevrons, m L B = distance between bottom of electrode and top of BASE tube, m L c = distance between BASE tubes top and chevrons, m L s = height of chevron's shield, m L T = distance between chevrons and condenser, m M = molecular weight of sodium, kg/mol, 23 gm/mol Ma = vapor Mach number, w"A/ypP Wp 0re = vapor mass flux in electrode pores, kg/m 2 s m z -vapor axial mass flow rate, kg/s m" = vapor axial mass flux, kg/m 2 s N = number of conical chevrons N B = number of (seried-connected) BASE tubes, 7 P = sodium vapor pressure, Pa Re = vapor Reynolds number, D e m"/jji R g = perfect gas constant, 8.314 J/mol K R p -average hydraulic radius of electrode pores, m, 10 jam T = temperature, K t E = thickness of cathode electrode, m, 5 ^m z = axial coordinate, m a = chevrons packing factor, Fig. 3 a 2= coefficient for advection of axial momentum y = specific heat ratio of sodium vapor, 5/3 AP = pressure loss through conical chevron's shield, Pa APcd = pressure loss due to condensation of sodium, Pa AP £ = pressure loss through cathode electrode, Pa APevap = pressure loss as a result of evaporation of sodium at BASE surface, Pa e £ = volume porosity of cathode electrode, 0.9 £ = correction factor for laminar flow in annulus 0 = angle of conical chevrons, Fig. 3 IJL = dynamic viscosity of sodium vapor, kg/m s £ = resistance coefficient for sudden expansion, Eqs. (13) and (14) p = vapor density (kg/m 3 ), PMI(R S T) 9 = compressible factor, Eq. (26) X = flow conductance of chevron's shield, m 2 /s Subscripts B = beta"-alumina solid electrolyte (BASE) c = cathode electrode/BASE interface cd = condenser ev = evaporator E = catho...

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Section: Pressure Drop Along the Base Tubesmentioning

confidence: 98%

“…The cell geometry used herein, the same as that used by Schock et al, 6 has a hot plenum cavity that feeds seven BASE tubes with high-pressure sodium vapor, a remotely located condenser, and a centerline liquid-return artery (Fig. 1).…”

mentioning

confidence: 99%

Sodium Vapor Pressure Losses in a Multitube, Alkali-Metal Thermal-to-Electric Converter

Tournier

El‐Genk

1999

Journal of Thermophysics and Heat Transfer

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“…Only a few investigators have attempted to establish a flow model to calculate the vapor pressure losses, owing to the complexity of the cell geometry and the fact that the vapor flow is in the transition or the free-molecular regime [23][24][25][26]. Schock et al [27,28] and Hendricks et al [29] developed complex thermal, electrical, and vapor flow models of vapor anode multi-tube AMTEC cells. Tournier et al [30] described a lumped analytical model of liquid anode single-tube and vapor anode multi-tube AMTEC cells.…”

Section: Analytical Model Of Amtecsmentioning

confidence: 99%

A review on advances in alkali metal thermal to electric converters (AMTECs)

Xiao

Cao

2009

Int. J. Energy Res.

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SUMMARYThe alkali metal thermal to electric converter (AMTEC) is one of the most promising technologies for direct conversion of thermal energy to electricity and has been receiving attention in the field of energy conversion and utilization in the past several decades. This paper aims to present a comprehensive review of the state of the art in the research and development of the AMTEC, including its working principles and types, historical development and applications, analytical models, working fluids, electrode materials, as well as the performance and efficiency improvement. The current two major problems encountered by the AMTEC, the time-dependent power degradation and relatively low efficiency compared to its theoretical value, are discussed in depth. In addition, a brief comparison of the AMTEC with other direct thermal to electric converters (DTECs), such as the thermoelectrics converter (TEC), thermionics converter, and thermophotovoltaics converter, is given, and combinations of different DTECs to further improve DTECs' power generation and overall conversion efficiency are demonstrated. Future research and development directions and the issues that need to be further investigated are also suggested. It is believed that this comprehensive review will be beneficial to the design, simulation, analysis, performance assessment, and applications of various types of AMTECs.

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Alkali Metal Thermal Electrochemical Converter

2023

Low‐Grade Heat Harvesting

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Parametric analyses of AMTEC multitube cells and recommendation for revised cell design

Cited by 20 publications

References 3 publications

Sodium Vapor Pressure Losses in a Multitube, Alkali-Metal Thermal-to-Electric Converter

Sodium Vapor Pressure Losses in a Multitube, Alkali-Metal Thermal-to-Electric Converter

A review on advances in alkali metal thermal to electric converters (AMTECs)

Alkali Metal Thermal Electrochemical Converter

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