Aerodynamic and Aeroacoustic Installation Effects for Pusher-Configuration CROR Propulsion Systems

Contra Rotating Open Rotor (CROR) propulsion systems have come back into focus as a possible economic and environmentally friendly powerplant for future transport aircraft. Having been widely applied to the simulations of single rotation propellers, the DLR CFD code TAU and the aeroacoustic analysis tool APSIM have been employed for the analysis of the complex aerodynamics and aeroacoustics of this type of aircraft propulsion system. Installation effects, i.e. the mutual interactions between airframe components and the rotors, have a pronounced impact on the aerodynamic and aeroacoustic performance for this type of engine. In this paper, the impact of the presence of the pylon is studied for a representative 10x8-bladed pusher-configuration CROR powerplant at typical cruise and take-off conditions. The numerical results allow for a detailed analysis of the aerodynamic interactions between the pylon and the rotors enabling for an improved understanding of the installation impact on blade loads and noise emissions