Modal Analysis of Commercial Aircraft Engine Noise Source and Noise Reduction Technology

Abstract

The reduction of aircraft engine noise has been a priority in the aviation industry for many years. It can cause community annoyance with various health hazard. Minimizing sound emission requires an understanding of engine noise. But it's a quite challenging due to the complex nature of aircraft systems and geometries. Using a model of an aero-engine duct, we provide a more in-depth look at the acoustical field in aircraft engines. Aircraft noise is a noise pollution produced by any aircraft or its components, during various phases of a flight: on the ground while parked such as auxiliary power units, while taxiing, on run-up from propeller and jet exhaust, during take-off, or landing. In this paper, the CFM 56 flow duct and blade is as the research object. And finally this model will show that: [1] Acoustic pressure field and pressure distribution for the cases of hard (top) and lined (bottom) duct wall with mean flow. [2] Compressible Potential Flow (cpf)--for modeling the background mean-flow velocity field as a potential flow. [3] Linearized Potential Flow, Boundary Mode (aebm)--for calculating the boundary eigenmode to be used as the source of the acoustic noise in the background mean-flow. [4] Linearized Potential Flow, Frequency Domain (ae, ae2)--for modeling the time harmonic acoustic field above and below the source plane.