Boundary Layer Ingestion (BLI) is a promising approach for improving propulsive efficiency in electrified aircraft by recovering wake momentum deficit and reducing propulsive power. In conventional aircraft, engines ingest freestream air while the low-momentum wake is unutilized, resulting in kinetic energy loss. The aft-BLI propulsor enables partial recovery of this lost energy. Despite renewed interest in BLI, many numerical studies remain limited to cruise-only evaluations or isolated propulsor modeling, without examining broader flight-envelope performance.
In this work, a numerical framework is developed to study electrified aft-section BLI on an A320 aircraft configuration across multiple operating conditions. Three configurations are considered: a baseline aircraft, a cruciform-tail configuration introduced to reduce tail–wake interaction, and an aft-mounted BLI-integrated configuration. Steady, compressible CFD simulations are performed in ANSYS Fluent using geometries generated in OpenVSP. An unstructured mesh with body-of-influence refinement and inflation layers is used. Cruise conditions are defined at an altitude of 11 km under ISA assumptions, with turbulence modeled using the k–ω SST formulation and electrified propulsion represented using an actuator disk approach.
Under cruise conditions, the baseline configuration yields a drag coefficient of Cd =0.04498 (53.28 kN drag, 591.6 kN lift) using a reference wing area of 123 m². The cruciform-tail configuration shows a small drag increase with negligible lift variation. Passive BLI installation increases drag to Cd =0.0471, corresponding to an aerodynamic penalty of ~4.8%. When the BLI propulsor is activated, a reduction in effective drag to Cd ≈0.044 is observed, corresponding to a 2% reduction relative to the baseline. Propulsive power requirements decrease from 16.34 MW to 14.35 MW, yielding a Power Saving Coefficient of ~11.6%.
A conservative assessment indicates a realistic propulsive power saving of ~7%. Overall, this work establishes a consistent numerical methodology and demonstrates the preliminary aerodynamic and propulsive potential of electrified aft-section BLI.
