Multi-Fidelity Design Approach for Rotor Blades in Low Speed Open Rotor Aeroacoustic Test Article

The Open Rotor Advanced Noise Control Fan (OR-ANCF), converted from NASA’s Advanced Noise Control Fan (ANCF), was developed as a flexible, low-TRL test platform for aeroacoustic and aeromechanic studies of open rotor propulsion systems. Open rotors offer significant fuel efficiency gains over traditional ducted turbofans, yet facing unsolved challenges associated with noise generation and complex aerodynamic interactions. The OR-ANCF supports NASA’s Efficient Quiet Integrated Propulsors (EQuIP) Technical Challenge, which aims to accelerate the development of advanced propulsion systems for subsonic aviation by addressing propulsion acoustics and improving technology readiness levels. The challenge emphasizes improving technology readiness levels to enable the adoption of open rotor systems while overcoming barriers posed by current design limitations. This paper describes a rotor blade design process for the OR-ANCF, utilizing a multi-fidelity design approach that integrates low-fidelity analytical tools with high-fidelity Computational Fluid Dynamics (CFD) simulations. The design objective is to achieve aerodynamic and aeroacoustic relevancy for both academic and industrial research, while addressing the operational constraints of the OR-ANCF test article. The redesigned rotor blades generate a comparable flow field and aeroacoustic characteristics of commercial aircraft takeoff conditions, achieved through iterative refinements to blade loading and tip geometry. This process enables future research in lower-TRL environments with constrained advance ratios, by providing valuable insights into flow field characterization and the effective control of blade-relative vortex trajectories across varying operating conditions.