초록 ▼

A hybrid mode-scattering/sound-absorbing segmented liner system and method in which an initial sound field within a duct is steered or scattered into higher-order modes in a first mode-scattering segment such that it is more readily and effectively absorbed in a second sound-absorbing segment. The m

A hybrid mode-scattering/sound-absorbing segmented liner system and method in which an initial sound field within a duct is steered or scattered into higher-order modes in a first mode-scattering segment such that it is more readily and effectively absorbed in a second sound-absorbing segment. The mode-scattering segment is preferably a series of active control components positioned along the annulus of the duct, each of which includes a controller and a resonator into which a piezoelectric transducer generates the steering noise. The sound-absorbing segment is positioned acoustically downstream of the mode-scattering segment, and preferably comprises a honeycomb-backed passive acoustic liner. The invention is particularly adapted for use in turbofan engines, both in the inlet and exhaust.

대표청구항 ▼

[ What is claimed is:] [1.] A hybrid mode-scattering/sound-absorbing segmented liner system for attenuating a sound field in a duct comprising:a mode-scattering segment capable of mode scattering an initial sound field in the duct;an active-control component within the mode-scattering segment compri

[ What is claimed is:] [1.] A hybrid mode-scattering/sound-absorbing segmented liner system for attenuating a sound field in a duct comprising:a mode-scattering segment capable of mode scattering an initial sound field in the duct;an active-control component within the mode-scattering segment comprising a controller, a reference signal determined from the initial sound field, and a sound-generating device, whereby the controller, in response to the reference signal, is capable of causing the sound-generating device to generate sound that mode scatters the initial sound field into an altered sound field; anda sound-absorbing segment positioned acoustically downstream of the mode-scattering segment and that is capable of attenuating the altered sound field, resulting in an attenuated sound field; rein the mode-scattering segment further comprises a passive liner positioned adjacent to the active-control components opposite the sound-absorbing segment.