Abstract
This paper discusses mass transport characteristic of sodium vapor in a miniature alkali metal thermal to electric converter (AMTEC) cell. The miniature AMTEC cell, which has larger packed electrode area in the same volume, is expected to have a feature to increase its volumetric power density. For the design of the cell discussed here, the main consideration is pressure drops due to sodium vapor flow between the cathode side electrode and the condenser surface. Mass transport characteristic in thin molybdenum electrode was measured with the sodium exposure test cell (SETC) in the temperature range of 900K to 1050K. The exchange current density and the electrode dimensionless mass transfer factor calculated from the measured limiting current are discussed. Based on the experimental results, the influence of the sodium vapor flow in the cathode side was evaluated. The preliminary parametric analysis shows that a miniature cell element with a sodium beta"-alumina tube of 1mm in outer diameter has a predicted output power of 8.5kW per unit. container base area.
