Assessment of Fan/Airframe aerodynamic performance using 360° uRANS computations: Code-to-Code comparison between ONERA, DLR, NLR and Airbus.

In todays context of increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards ever increasing bypass ratio engine designs, with so-called Ultra-High Bypass Ratio (UHBR) engines becoming an interesting option as a potential powerplant for future commercial transport aircraft. These engines promise low specific fuel consumption at the engine level, but the resulting size of the nacelles pose challenges in terms of the installation on the airframe. Thus their integration on an aircraft requires careful consideration of complex engine-airframe interactions impacting performance, aeroelastics and aeroacoustics both on the airframe and the engine sides. As a partner in the EU funded Clean Sky 2 project ASPIRE, ONERA, DLR and NLR are contributing with Airbus to an investigation of numerical analysis approaches, which draws on a generic representative UHBR engine configuration specifically designed in the frame of the project. In the present paper, a code-to-code comparison of 360° uRANS computations, including an isolated nacelle with a geometrically fully modeled fan and OGV (Outlet Guide Vane) stage, is proposed. This code-to-code comparison is done between the structured solver of the elsA code (structured and unstructured ONERA-Airbus-Safran code, developed by ONERA), the ENFLOW solver (structured, developed by NLR), the TRACE solver (structured, developed by DLR), the TAU solver (unstructured, developed by DLR). Results are presented in terms of global values (Mass-flows, Fan Pressure and Temperature Ratio, efficiencies) and local flow distributions.