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

Abstract

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.