Multi-physical topology optimization of hydrogen-driven solid oxide fuel cells toward advanced hybrid power systems for green unmanned aerial vehicles

Green aviation has accelerated the development of solid oxide fuel cell-gas turbine (SOFC-GT) hybrid power systems as high-efficiency and low-emission propulsion technologies. Despite recent progress, cell-level optimization of SOFCs involving multi-physical process remains underexplored, and the associated system-level integration into unmanned aerial vehicles is not yet fully realized. To address this gap, we develop a framework that combines electrochemical, mass transport, and fluid flow processes within topology optimization, enabling the design of optimized SOFC structures and multiscale performance analysis. The results reveal a critical balance between flow channels for oxygen delivery and interconnect ribs for electron conduction. The structural design should include finely branched and smoothly connected channels to enhance mass transport, while maintaining sufficient rib coverage to support efficient electron conduction. An optimal configuration is identified at θ ∗ = 0.55, which improves single-cell power by 46.34 % and power-to-weight ratio by 55.69 % compared to the conventional straight-channel design. Moreover, the synergistic effects of topology optimization and enhanced electrode conductivity exhibit a complementary improvement. This integration enables the hybrid power system to achieve a 17.77 % increase in power-to-weight ratio and a 15.71 % improvement in flight endurance, accompanied by a significant reduction in CO₂ emissions. Our study establishes a unified pathway for bridging cell-level electrochemical optimization with system-level performance enhancement, offering both theoretical guidance and engineering feasibility for sustainable aviation applications.