Modeling Boundary Layer Ingestion Using a Coupled Aeropropulsive Analysis

Abstract

The single-aisle turboelectric aircraft with an aft boundary layer propulsor aircraft concept is estimated to reduce fuel burn by 12% through a turboelectric propulsion system with an electrically driven boundary layer ingestion propulsor mounted on the fuselage tail cone. This motivates a more detailed study of the boundary layer ingestion propulsor design, which requires considering the fully coupled airframe propulsion integration problem. However, boundary layer ingestion studies thus far have accounted only for the aerodynamic effects on the propulsion system, or vice versa, but have not considered the two-way coupling. This work presents a new approach for building fully coupled aeropropulsive models of boundary layer ingestion propulsion systems. A one-dimensional thermodynamic cycle analysis is coupled to a Reynolds-averaged Navier–Stokes simulation. This aeropropulsive model is used to assess how the propulsor design affects the overall performance for a simplified model of the single-aisle turboelectric aircraft with an aft boundary-layer propulsor. The results indicate that both propulsion and aerodynamic effects contribute equally toward the overall performance and that the fully coupled model yields substantially different results compared to the uncoupled model. Although boundary layer ingestion offers substantial fuel burn savings, it introduces propulsion-dependent aerodynamic effects that need to be accounted for.