Power Balance Analysis Experiments on an Axisymmetric Fuselage with an Integrated Boundary-Layer-Ingesting Fan

Abstract

Boundary Layer Ingestion (BLI) is a promising propulsion integration technology capable of enhancing aircraft propulsive efficiency. The Propulsive Fuselage Concept (PFC), a tube-and-wing configuration with an aft-fuselage-mounted BLI propulsor, is particularly suited for BLI. Although extensively studied on a system level, the aerodynamic performance of the PFC, resulting from the complex interaction between the airframe and the propulsor, is still largely uncharted. In this paper, the results of wind-tunnel tests on a simplified PFC model are presented. The model featured an axisymmetric fuselage body with an integrated BLI shrouded fan. Flowfield measurements were performed through particle image velocimetry to analyze the key aerodynamic phenomena and to assess the distribution of momentum and mechanical energy around the aft-fuselage propulsor. Results show that the BLI fan alters the surrounding flowfield by increasing the mass flow in the inner part of the fuselage boundary layer and by reducing the boundary-layer thickness. Moreover, the power analysis indicates that the potential benefit of BLI is strongly dependent on the fan setting. Increasing the fan shaft power leads to a higher amount of power dissipated in the near wake. However, an increasing share of the energy flux is associated with the momentum excess contained in the wake.