Aerodynamics and Loss Accounting of a Low Pressure Ratio Fan for an Over-Wing Mounted Engine

In recent research, several Boundary Layer Ingesting propulsors concepts have been investigated with varying degrees of airframe integration. The contribution compares the well-known approach of a \(60^\circ \) circumferential inlet distortion with a configuration of a partly wing-embedded and a fully embedded engine integration. The second type is characterized by a local distortion while the whole flow field of the third shows flow variations. Conventional distortion metrics are getting close to their limits for an adequate assessment. The focus of this contribution lies in highlighting differences in loss generation through the fan stage and at dedicated stations. The stator blade row has a changing role in terms of entropy production, depending on the distortion type. Concepts for a stator refitting are presented and successfully applied. Almost one-third of efficiency drop is recovered for the final design change.