The attenuation of fan tones remains an important aspect of fan noise reduction for high bypass ratio turbofan engines. However, as fan design considerations have evolved, the simultaneous reduction of broadband fan noise levels has gained interest. Advanced manufacturing techniques have also opened new possibilities for the practical implementation of broadband liner concepts. To effectively address these elements, practical acoustic liner design methodologies must provide the capability to efficiently predict the acoustic benefits of novel liner configurations. This paper describes such a methodology to design and evaluate multiple candidate liner configurations using realistic, three dimensional geometries for which minimal source information is available. The development of the design methodology has been guided by a series of studies culminating in the design and flight test of a low drag, broadband inlet liner. The excellent component and system noise benefits obtained in this test demonstrate the effectiveness of the broadband liner design process. They also illustrate the value of the approach in concurrently evaluating multiple liner designs and their application to various locations within the aircraft engine nacelle. Thus, the design methodology may be utilized with increased confidence to investigate novel liner configurations in future design studies.

对于高涵道比涡扇发动机，风扇音调的衰减仍然是降低风扇噪音的一个重要方面。然而，随着风扇设计考虑的发展，同时降低宽带风扇噪音水平引起了人们的兴趣。先进的制造技术也为宽带衬垫概念的实际实施开辟了新的可能性。为了有效地解决这些因素，实用的声学衬垫设计方法必须能够有效预测新型衬垫配置的声学优势。本文描述了这样一种方法，该方法使用可获取最少源信息的逼真的三维几何形状来设计和评估多个候选衬垫配置。设计方法的发展受到了一系列研究的指导，这些研究最终在低阻力、宽带进气衬管的设计和飞行试验中达到了高潮。在该测试中获得的出色组件和系统噪声优势证明了宽带衬垫设计过程的有效性。它们还说明了该方法在同时评估多个班轮设计及其在飞机发动机短舱内不同位置的应用方面的价值。因此，可以更有信心地利用设计方法来研究未来设计研究中的新型衬管配置。它们还说明了该方法在同时评估多个班轮设计及其在飞机发动机短舱内不同位置的应用方面的价值。因此，可以更有信心地利用设计方法来研究未来设计研究中的新型衬管配置。它们还说明了该方法在同时评估多个班轮设计及其在飞机发动机短舱内不同位置的应用方面的价值。因此，可以更有信心地利用设计方法来研究未来设计研究中的新型衬管配置。