Air vent noise prediction for a commercial aircraft's environmental control system

This paper presents an approach to characterize the noise produced by an air vent of the Environmental Control System (ECS) for a regional transportation aircraft. The analyses have been conducted for different values of inlet mass flow rate on 2-D and 3-D models. Noise computations have been made in different points of control volume (Receivers) to better predict the volume distribution of sound pressure. The Ffwocs Williams–Hawkings model has been used for aero-acoustic analysis which is based on the Lighthill acoustic analogy generalized with the inclusion of moving surface. The k-ε turbulence RANS model in its “Realizable” version has been used and all simulations have been accomplished by the use of the STAR-CCM+ CFD software. The Sound Pressure Level (SPL) in the hearing range measured in the receivers, opportunely rescaled in according to weighting curves (dBA), have been filtered in octave bands. These curves have been successively compared with Noise Criteria curves, that establish the maximum SPL acceptable level for the different environments