Hybrid Axial and Cross-Flow Fan Propulsion for Transonic Blended Wing Body Aircraft

The challenges of the next century of aviation will require innovative and revolutionary concepts to meet air transportation demands. One NASA vision for future transport-sized aircraft includes the blended-wing-body (BWB) platform with embedded, distributed propulsion as a means for increased efficiency and reduced noise. In cruise, embedded propulsion benefits from boundary layer ingestion and wake filling, resulting in high propulsive efficiency. However, several challenges exist, including inlet nozzle design, propulsor design for ingestion of highly non-uniform inflow, and propulsor/airframe support structure optimization. This work proposes a hybrid turboelectric propulsion system incorporating small embedded, distributed cross-flow fans (CFF) for boundary layer control and wake filling, and much larger axial fans for primary thrust. Bringing together the best qualities of both axial and CFF propulsion, a substantial improvement in overall vehicle efficiency is possible. CFD and analytical analyses will be used to investigate the flow field and range of application for such a system. Comparisons will be made with published baseline designs with respect to power requirements, component weights, support structure, and other key parameters.