DESIGN OF AN ACTIVE NOISE CONTROL SYSTEM FOR A BUSINESS JET WITH TURBOFAN ENGINES

Kurzfassung

An active noise vibration control (ANVC) system is designed for a Dassault Falcon 2000LX business jet. Measurement data from ground tests and recordings from cruise flight reveal narrowband and tonal cabin noise in the bandwidth from 50 Hz to 500 Hz. In both conditions the sound pressure level (SPL) of the tonal components is up to 10 dB above the cabin noise floor. The designed ANVC system is expected to reduce the tonal components to the noise floor. The system is realized on the ceiling panel in the aft of the cabin. A frequency domain filtered-x least mean squares algorithm (FxLMS) is used for control. The main design task is the definition of actuator (inertial exciter) and error sensor (microphone) locations on the ceiling panel and in the cabin fluid. measurement data from a ground vibration test of DLR test aircraft iSTAR is used for the identification of suitable actuator and sensor locations. The system performance is predicted with numerical simulations using sampled sound pressures and identified frequency response functions (FRF). The sound pressures are recorded at 312 locations in the volume of the aft cabin. FRF from 48 actuator locations to 312 microphone locations are available for optimization. The system will be realized in the iSTAR in July 2023. Ground tests will be performed with engine excitation up to 80% N1 (rotational speed of low the pressure compressor shaft).