Design and Testing of a TRL-3 Open Rotor for Aeroacoustics and Aeromechanics Research

The NASA Advanced Noise Control Fan Facility (ANCF) was used with a new open-rotor test article. The goal was to understand the test article design space such that the salient aeroacoustic and aeromechanical characteristics of a modern open-rotor engine design were represented. The facility was operated in an outdoor environment where the ambient conditions were uncontrollable. A design advance ratio of 𝐽 = 0.325 was selected based on a statistical analysis of historical ambient data at the outdoor test site. A multi-fidelity design loop allowed a rotor blade design that mimicked the blade loading and tip vortex trajectory of a reference design representing take-off conditions associated with an advance ratio of 𝐽 = 1.0. Results from outdoor experiments involving the rotor blades are presented. The experiments consisted of fixed fan speed, rotor blade pitch and variable advance ratio and angle of attack. The configurations and measurements were limited as this entry was intended to evaluate the proof-of concept and initial operating capability. Wind, far-field radiated noise, and rotor blade strain measurements are described.