Numerical Simulation of Nacelle Flowfield for Counter-Rotating Open Rotor Propellers

This paper summarizes the development of a tool for designing axisymmetric nacelles for counter-rotating open rotor (CROR) engines, based on predefined geometries, global input relations and one-dimensional perfect gas equations. A nacelle geometry was generated to match the flight conditions and base dimensions of the Airbus AI-PX7 CROR propeller. Furthermore, the 3D turbulent flowfield around the nacelle was evaluated via Computational Fluid Dynamics (CFD) for four different angles of attack: 0\ub0, 4\ub0, 6\ub0 and 8\ub0. The computations were performed for the nacelle without the propellers as a first analysis. The formation of shock waves, boundary layer separation and inlet flow distortion were the main parameters of the CFD study. The nacelle design was considered to be successful as a preliminary approach, since, even for the highest angle of attack, no critical conditions for the engine performance were detected