Experimental Method of Segmented Acoustic Liners Performance in Noise Reduction

Aero engine noise contributes one of the most significant far-field noise sources during aircraft take-off, and fan noise dominates the aero engine noises. Experimental method was employed to study the noise absorbing ability of both segmented and uniformed acoustic liners in terms of the engine fan noise reduction. Noise reduction performance test method and platform were introduced in the first place. Then the employed in-duct acoustic decomposition method was deployed. Finally, by applying both in-duct acoustic mode decomposition and far-field noise analysis, the noise reduction performances of both liners were studied experimentally. As concluded, both uniformed and segmented liners exhibited promising performance in noise reduction for both sound power level and directivity at expected modes and frequencies. In terms of broadband noise reduction, segmented liner shown more significant noise reduction performance.