A Fully Coupled Body Force-Engine Performance Methodology For Boundary Layer Ingestion

In reason of their potential improvements in fuel consumption, disruptive propulsion concepts such as Boundary Layer Ingestion are lately earning the attention of the aerospace community. Because of the increased level of multi-disciplinary interactions brought by the tight airframe-propulsor integration, an accurate assessment of this benefit requires a detailed study of the engine behavior from both an aerodynamics and an overall performance stand- point. In this context, this paper presents a fully coupled methodology that integrates a 0D thermodynamic cycle analysis of the core and a 3D body force representation of the fan stage into a single numerical computation. This approach allows to simulate fan-distortion interactions and engine overall performance efficiently in terms of accuracy vs. computational cost trade-off, making it well-suited for conducting full aircraft-engine CFD calculations. The coupling is demonstrated in the assessment of boundary layer ingestion impacts on the small DGEN 380 turbofan. Results provide a quantification of such impacts on fan efficiency, engine power demand, thrust specific fuel consumption, flow distortion transfer and fan aeromechanical response for different levels of engine net thrust.