A Comprehensive Study on Hydrogen and Hybrid Electric Aircraft with Distributed Electric Propulsion

With increasing environmental concerns, reducing CO2 emissions from transportation systems has become a priority. To this end, hybrid-electric and hydrogen combustion aircraft are explored. However, these aircraft are facing challenges in meeting the performance demands of conventional aircraft. Therefore, distributed electric propulsion (DEP) has gained attention owing to its potential to improve aerodynamics, take-off, and landing performance. Several conceivable concepts explore DEP. Although individual architectures, such as battery hybrid-electric architecture with DEP, have been well investigated, little research comprehensively compares the feasibility of each propulsion architecture. Hence, this study addresses the optimal design of a regional aircraft with hybrid-electric propulsion, considering several architectures, including hydrogen combustion and fuel cell electrification. Herein, three aircraft of different sizes were investigated to fulfill requirements comparable to the baseline aircraft. The goal is to understand the optimal architecture for aircraft with DEP in the context of environmental impact. The hybrid propulsion architectures, including hydrogen fueling, fuel cell, and battery electrification, are modeled using electrification factors. The aerodynamic effects of DEP are estimated using the actuator disk theory. Finally, the feasibility of each architecture with DEP is addressed, and each characteristic is investigated. The analysis underscores the advantageous role of the parallel hybrid with electric fans in reducing well-to-wake carbon intensity, highlighting the substantial contribution of DEP in minimizing the environmental impact. Additionally, the study emphasizes the considerable influence of the aspect ratio on the well-to-wake carbon index.