Computer Method For Design Of Acoustic Liners For Turbofan Engines PDF Download

The freeform geometry enabled by additive manufacturing (AM) gives designers many unique capabilities, which has led to novel uses in numerous engineering applications. One emerging use of these freeform AM structures is in aircraft acoustic liners. Modern aircraft have increasingly adopted acoustic liners to reduce the sound emitted by their turbofan engines to meet acoustic emission requirements. Most current acoustic liners take the form of micro-perforated panel (MPP) absorbers. Although traditional MPPs absorb specific tones well, they do not perform as well over a wide range of frequencies. As future aircraft engines start to utilize high-bypass ratios, acoustic liners that can attenuate a wide range of sound frequencies (low-frequencies in particular) with a reduced form factor are needed. Developing a conventional acoustic liner with adequate broadband absorption that also meets size and weight requirements is challenging, expensive, and time-consuming. Therefore, a new integrated design and development method for aircraft acoustic liners is needed to address this barrier. A rapid design and development workflow that uses AM for creating complex novel acoustic liner geometries is presented. This new methodology can help support the development of acoustic liners that are needed for future aircraft engines by allowing the design space to be expanded and explored in ways previously impossible or too expensive to fabricate.