Boundary Layer Ingestion (BLI) is a promising technology for reducing the impact of aviation on the environment. By placing a propulsor on an aircraft such that it ingests the slower moving air within the boundary layer, a decrease in power consumption can be achieved. Evaluating the performance of BLI configurations remains a challenge though. Many conventional methods for computing the thrust and drag of an aircraft cannot be used due to the interference between the airframe and the propulsor. As a result, researchers have to rely on either low fidelity methods with limited accuracy, or on expensive CFD simulations. In this work, an attempt was made to create a computationally inexpensive method that can evaluate the drag, thrust and propulsive power of an axisymmetric fuselage with a BLI propulsor. The method proposed relies on potential flow modeling and makes use of a boundary layer model and several corrections.

It is the need of the hour to focus research and development towards curbing emissions due to the growing aviation industry. Employing boundary layer Ingesting(BLI) propellers for development of propulsive fuselage concept(PFC) aircraft while utilizing hydrogen as an alternative energy source, is the idea behind project APPU(Advanced Propulsion and Power Unit). However, the empennage wake is detrimental to the propeller. This study uses chord-wise wake blowing technique to fill the empennage wake in order to mitigate the detrimental effects of the wake on the inflow of the aft mounted BLI propeller. A near complete wake filling was observed for the blown configuration, with a 99.7% uniformity in the velocity profiles for the filled empennage wake. The addition to the overall aircraft drag due to the wake blowing system was less than 2 drag counts and a mass flow rate of 0.91-1.23Kg/s was found to be required in the blown cases.