Computational analysis of an ammonia-fuelled hybrid solid oxide fuel cell–gas turbine propulsion system for commercial aviation

Abstract

This study investigates the performance of a hybrid solid oxide fuel cell–gas turbine (SOFC-GT) propulsion system for commercial aviation, using ammonia–hydrogen blends as fuel. A computational model was developed by combining NASA’s T-MATS toolbox with Cantera-based chemical equilibrium calculations to simulate thermodynamic, aerodynamic, and electrochemical interactions. The analysis examined key design and operational parameters, including fan pressure ratio (FPR), bypass ratio (BPR), equivalence ratio, altitude, and Mach number. Results showed that pure ammonia produced the highest thrust (14.5 MW total power and 2.2 kg/s fuel flow) but at the cost of lower thermal efficiency and higher specific fuel consumption (SFC). Increasing the hydrogen content in the fuel reduced fuel flow by up to 86%, improved thermal efficiency by 4.5%, and eliminated CO${}_2$ emissions, though NO emissions increased by 20%. Variations in equivalence ratio demonstrated a trade-off between thrust and efficiency, with net thrust increasing by 68% and thermal efficiency decreasing by 34% as equivalence ratio rose from 0.24 to 0.8. Optimal FPR and BPR combinations improved net thrust by up to 35% and reduced SFC by 26%. Although the hybrid system’s power-to-weight ratio was 30%–37% lower than that of a conventional turbofan, advancements in lightweight SOFC materials and designs could enhance feasibility. These findings demonstrate the potential of SOFC-GT systems to enable zero-carbon aviation while maintaining competitive performance metrics.