Acoustic measurement for resin-based acoustic liner on turbofan engine testbed

Abstract

Acoustic liner is one of the most effective devices for suppressing fan noise emitted by aircraft engines. IHI and Japan Aerospace Exploration Agency (JAXA) have developed a resin-based acoustic liner for fan noise attenuation that is lighter than conventional acoustic liners in production. In this study, an acoustic measurement of the full-scale resin-based acoustic liner was conducted on the turbofan engine testbed installed at the JAXA test facility to evaluate its noise reduction capability in actual operating environment. The in-duct and in-cell acoustic measurements were performed during the test campaign. A baseline hardwall liner and the production acoustic liner were also tested for comparison. The tonal and broadband fan noise reduction of the resin-based acoustic liner relative to the hardwall liner was evaluated as well as that of the production acoustic liner. According to the test results obtained in the enclosed testbed, it was found that the resin-based acoustic liner has good noise reduction performance as expected for typical acoustic liners. The maximum noise reduction is equivalent to the production acoustic liner for both tonal and broadband components over the wide range of engine power settings.