Conceptual Design and Mission Analysis for a Geared Turbofan and an Open Rotor Configuration

In this multidisciplinary study a geared open rotor configuration is assessed and compared to an ultra high bypass ratio geared turbofan engine. Both designs assume a 2020 entry into service level of technology. The specific thrust level for minimizing block fuel and the resulting engine emissions for a given mission is sought. The tool used contains models that effectively capture: engine performance, mechanical and aerodynamic design, engine weight, emissions, aircraft design and performance as well as direct operating costs. The choice of specific thrust is a complex optimization problem and several disciplines need to be considered simultaneously. It will be demonstrated, through multidisciplinary analysis, that the open rotor concept can offer a substantial fuel saving potential, compared to ducted fans, for a given set of design considerations and customer requirements. NOMENCLATURE ∆h0 Stagnation enthalpy change ηpol Polytropic efficiency A Annulus area AR Axial Aspect Ratio BPR Bypass Ratio CO2 Carbon dioxide D Propeller diameter [m] DDTF Direct Drive Turbo Fan DOC Direct Operating Cost DREAM valiDation of Radical Engine Architecture systeMs EINOx Nitrogen Oxides Emissions Index EIS Entry Into Service FAR Federal Aviation Regulations FB Fuel Burn FL Flight Level FP7 Seventh Framework Program FPR Fan Pressure Ratio GOR Geared Open Rotor GTF Geared TurboFan GTFSR Short Range Geared TurboFan hb Blade height HPC High Pressure Compressor HPT High Pressure Turbine ICAO International Civil Aviation Organization IPC Intermediate Pressure Compressor ISA International Standard Atmosphere IPT Intermediate Pressure Turbine K Blade volume factor LT Long Term LTO Landing and Take-Off LR Long Range MT Medium Term N Rotational speed NOx Nitrogen Oxides OEM Original Equipment Manufacturer OPR Overall Pressure Ratio PW Power RQL Rich-burn/Quick-quench/Lean-burn SFC Specific Fuel Consumption SLS Sea Level Static SR Short Range T4 Burner exit temperature T/O Take-Off TEC Turbine Exhaust Case TET Turbine Entry Temperature Umid Mid section blade speed UHBR Ultra High Bypass Ratio UDF Un-Ducted Fan