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A modified actuator disk method based on blade element momentum theory is applied to an UHBR turbofan engine with the DLR TAU Code. The method is compared against RANS simulations with a common thermodynamic engine boundary condition and high-fidelity 360°u RANS simulations as well as RANS mixing-plane data from the design process of the engine conducted with the DLR flow solver TRACE. The input data of the actuator disk model comprise sectional lift and drag coefficients of the rotor and stator blades which are obtained by 2D RANS computations of the blade sections performed with the TAU Code. The boundary conditions for these 2D computations are derived from the aforementioned RANS mixing-plane results obtained during the design process of the investigated engine.Good agreement between the RANS actuator disk method and the uRANS results as well as the RANS mixing-plane data is observed. The actuator disk model is able to predict global engine performance data for different engine operating points. Detailed analysis shows that the actuator disk model is able to reproduce characteristic non-uniform inflow phenomena that could in the past only be modeled with uRANS computations. Additionally the model is capable to accurately predict the thrust distribution between rotor and stator. Therefore it is able to fill the gap between the currently used thermodynamic engine boundary condition and high-fidelity uRANS computations with only a minor increase in required computational resources.

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The implementation of advanced propulsion systems to ensure aviation meets the increasingly stringent environmental and economic pressures is a key building block in the development of future transport aircraft. A promising technology is the utilization of boundary layer ingesting (BLI) propulsion concepts, which are seen to offer an improvement of the engine propulsive efficiency in tandem with a reduction of the overall aircraft wake dissipation losses. In a collaborative study between the DLR Institute of Aerodynamics and Flow Technology, the DLR Institute of Propulsion Technology and industrial partners, a comprehensive study of the potential of implementing BLI concepts for future single-aisle short-to-medium range transport aircraft has been conducted. The present paper presents the result of an overall aircraft aerodynamic study, in which an aft BLI propulsor, specifically designed for this particular application, is investigated in its installation on the tail of a single aisle aircraft configuration at cruise flight conditions. A detailed aerodynamic analysis is presented, with a focus on comparing the results achievable through various BLI engine modeling approaches, which include the use of a classical engine boundary condition, a body force model as well as a full representation of the fan and OGV stage in a uRANS simulation approach. In addition to the study of the mutual aerodynamic interactions between the airframe and propulsor, some key aspects of the highest fidelity uRANS simulation approach are also discussed.