Engine-Airframe Installation Effects for Open Fan Powered Aircraft at Take-Off Conditions

Abstract

Open Fan Propulsion Systems promise a significant improvement in specific fuel consumption over present turbofan engines, which they derive from their ultra-high bypass ratio, made possible through the omission of the nacelle around rotor and stator. This type of propulsion system aims to retain many of the efficiency benefits of the Contra-Rotating Open Rotor (CROR), studied intensively in many research efforts in the past decade, while eliminating the main drawbacks of weight and complexity of that type of engine. As for any open rotor or propeller, angle of attack and installation effects are an important consideration for both the aerodynamic performance as well as the noise emission characteristics of this engine. In numerical studies of an isolated and installed Open Fan in the frame of the EU-funded Clean Sky 2 project, notable installation effects were found to affect the aerodynamic performance of both the propulsion system as well as the airframe.