Thermodynamic performance of an innovative space nuclear Brayton cycle with S–N₂O

The supercritical Brayton cycle system is renowned for its characteristics of elevated high-power density, compact structure, lightweight design, and extended operational lifespan, rendering it as a preeminent energy conversion approach for space nuclear power systems. Using nitrous oxide (N₂O) as the working fluid in a supercritical Brayton cycle system enables heightened efficiencies at comparatively lower cycle temperatures. This study examined four distinct layout configurations, culminating in an in-depth analysis of their respective thermodynamic performances. Among the configurations analyzed, the newly proposed recompression Brayton cycle with partial cooling and heat recovery (RBC-PCHR) layout exhibited the best thermodynamic performance compared to other cycle configurations. This superiority can be principally attributed to augmented heat recovery procedures and reduced compression workloads. A detailed multi-objective optimization strategy is subsequently embarked upon, building upon the insights gained from the sensitivity analysis pertaining to the key operating parameters. The optimization outcomes show significant enhancements, with an increase of 1.37% in η_th and 32.18% in M_BRU, along with a marginal decrease of 0.70% in η_ex.