Performance evaluation and comparative analysis of a novel aviation SOFC-Turboprop hybrid system utilizing chemical recuperation for hydrogen production

Facing the urgent need for aviation carbon reduction, this study proposes a novel SOFC-GT hybrid system specifically for aviation applications. This hybrid system integrates SOFCs with a turboprop engine by employing chemical recuperation for hydrogen production and decoupling compressor from turbine (SOFC-Turboprop system). In this study, design evaluations of the key component parameters of the SOFC-Turboprop system were conducted, and performance comparisons were made between it and conventional turboprop engines under various design conditions. In addition, effects of engine design parameters and flight conditions on performance were investigated. The results indicate that SOFC fuel utilization rate and reforming steam-to-carbon ratio must be optimized to balance performance with carbon reduction. Higher reforming temperature can simultaneously improve fuel economy and carbon reduction. Under equal output power, the SOFC-Turboprop system exhibits a 22.80 % increase in overall efficiency and turbine inlet temperature (TIT) decrease of 268.54 K compared to a conventional turboprop engine. Under identical TIT, overall efficiency and output power increase by 29.02 % and 41.14 %. Notably, the SOFC-Turboprop system overcomes the conventional engine's limitations associated with pressure ratio, as its output power continuously increases with pressure ratio, achieving a maximum improvement exceeding 50 % compared to conventional engines. Moreover, output power advantage is even more pronounced at lower altitudes, with an improvement of over 60 % and significantly enhanced fuel economy at low speed. These findings suggest that the SOFC-Turboprop system has more distinct performance advantages in low speed and altitude, although trade-offs between fuel economy and carbon emissions must be carefully balanced.