A thermionic converter with a planar, macro-grooved emitter and 0.5 mm Gap

Abstract

Performance parameters of a thermionic converter with a planar, macro-grooved, Molybdenum emitter and a 0.5 mm gap were compared with those of a smooth electrodes converter. At an emitter temperature of 1573 K and a collector temperature of 1073 K, peak electric power density (0.45 W/cm2) and peak conversion efficiency (5.3%) were higher than those for the smooth electrodes converter (0.35 W/cm2 and 5%, respectively). When the emitter and collector temperatures were increased to 1773 and 1173 K, respectively, the peak electric power density (1.2 W/cm2) and the peak conversion efficiency (∼8% at PCs=400 Pa) of both converters were same. At lower emitter (1673 and 1573 K) and collector (1073 K) temperatures, the electric power density and the conversion efficiency of the grooved emitter converter were 15–20% higher than that for the smooth electrodes converter in the ignited mode. The barrier index (2.15 V) was ∼8% lower than that of the smooth electrodes converter when the emitter and collector temperature...