Performance analysis of a multitube vapor-anode AMTEC cell

Tournier, Jean‐Michel; El‐Genk, Mohamed S.; Huang, Lei; Schüller, Michael

doi:10.1109/iecec.1997.661934

Cited by 11 publications

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this annulus, the conservation of axial momentum can also be expressed by Eq. (7). D in this region was obtained from the first approximation of the DGM as…”

Section: Pressure Loss In Annulus Above Base Tubesmentioning

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

View full text Add to dashboard Cite

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...

show abstract

“…In this annulus, the conservation of axial momentum can also be expressed by Eq. (7). D in this region was obtained from the first approximation of the DGM as…”

Section: Pressure Loss In Annulus Above Base Tubesmentioning

confidence: 99%