AMNESIA II: Body-force model for universal application of fan intake flows with inflow distortions

• Applicant: Professor Dr.-Ing. Jens Friedrichs
• Subject Area: Hydraulic and Turbo Engines and Piston Engines
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 578814512

The aviation industry is striving to increase the overall efficiency of aircraft engines by improving the power-to-weight ratio. This results in engine designs that operate near the limits of aerodynamic, thermal, and structural components. The two-spool engine, particularly Ultra-High-Bypass-Ratio (UHBR) turbofans, plays a key role here. Increasing the bypass ratio improves propulsion efficiency, but also increases weight due to technologies such as gearboxes and larger diameters. In order to minimize drawbacks such as increased aerodynamic drag from larger frontal areas, shorter engine intakes are being considered. However, these shorter intakes pose aerodynamic challenges, especially under critical operating conditions. Addressing these challenges requires precise intake design that takes into account the fan’s influence on intake aerodynamics. Reduced models offer a way to reduce resource requirements by accepting minor compromises in detail. A reduced model such as the Body Force Model (BFM) can capture the aerodynamic impact of the fan on the intake while saving computational resources. Experiments are needed to accurately quantify the interaction between the intake and the fan. The Institute of Jet Propulsion and Turbomachinery of TU Braunschweig has the INFRa-Rig to experimentally assess these interactions under critical operating conditions. In earlier work, various BFM approaches were investigated. This approach was integrated into commercial software and applied to a transonic fan stage, achieving up to tenfold resource savings compared to full-annulus simulations. The aim of the proposed project is to further develop the BFM by improved loss-modelling approaches which also cover coupleed intake-fan aerodynamics and validate it with experimental results. Calibration-free modeling of part-load behavior and demonstrating the model’s general applicability to different fan geometries are central aspects of the proposed research. Thus, various turbofan blade geometries available at IFAS—including the V2500-A1 turbofan blade geometry—will be examined using the model, compared with conventional RANS results, and evaluated. In addition, the BFM will be applied to real inlet distortions and validated against experimental data.

• DFG Programme: Research Grants