The Advanced Noise Control Fan

Research Area: Acoustics

The noise created by aircraft engines remains a challenge for both passengers and communities in proximity to airports. The engine’s fan, visible from the front of the aircraft, creates the majority of the engine thrust. The fan also creates significant acoustic noise. The Advanced Noise Control Fan (ANCF) facility was developed in order to study new technologies intended to reduce fan and engine noise.

The fan has a 4 feet diameter and a centerline height of 8 feet from the ground. The facility was built at the Aeroacoustic Propulsion Laboratory (AAPL) facility at NASA Glenn Research Center (GRC) in 1994. Sutliff provides a comprehensive summary of the work achieved by the ANCF at NASA GRC for over two decades. The ANCF has been located and operated at the University of Notre Dame since 2016.

Acoustic liners are materials used in the casing in order to reduce the transmission of fan noise outside of the engine. Two novel acoustic liner technologies have recently been designed and tested in the ANCF. The acoustic liner cells dissipate acoustic energy into heat. They reduced the sound pressure level (SPL) of the first harmonic of the fundamental tone of the ANCF by 18 dB. Acoustic-to-flow energy conversion devices harvest the acoustic energy of a tone to provide unsteady momentum injection. They reduced the SPL of the fundamental tone of the ANCF by 23 dB.