Engine Architecture for High Efficiency at Small Core Size

Abstract

This technical article discusses architectural design and requirements for high-efficiency engines. Advanced fuel-efficient commercial aircrafts for entry into service in 2035 have quite different configurations than current transports, requiring new architectures for their jet engines. The alternative engine architecture potentially enables a high-overall pressure ratio all-axial compression system at small core size, while maintaining high compressor and turbine efficiencies. The concept engine also makes use of the reverse angled core to address the FAA 1-in-20 rule. It is noted that the reverse angled core engine concept architecture is only feasible at ultra-high bypass ration such that the core engine can be packaged within ducting positioned crosswise to the fan exit flow. Future studies would consider 3D design of the high turning ducts and compressor design technology for reduced exit Mach number to further increase exit annulus height and reduce sensitivity to tip clearances.