Acoustic liner - Wikipedia
An acoustic liner is a sandwich panel made by: a porous top layer, called face-sheet; a honeycomb structure providing internal partitions; an impervious layer, called back-sheet or back-skin; The lower half of a liner features dedicated internal slots to allow liquid drainage in order to prevent ice formation or fire hazards.
Single-layer and double-layer liners with perforate and mesh facing sheets are standard on aero-engines, but more research is required to understand their acoustic impedance characteristics. More research is also required into novel liner designs and novel materials for acoustic liners.
Interest in characterization of the aerodynamic drag of acoustic liners has increased in the past several years. This report details experiments in the NASA Langley Grazing Flow Impedance Tube to quantify the relative drag of several perforate-over-honeycomb liner configurations at flow speeds of M=0.3 and 0.5.
Development of acoustic liner in aero engine: a review - Springer
2020年8月11日 · To dampen the broadband noise and resist the harsh service conditions with high temperature and pressure in modern turbofan engine, new acoustic liner concepts are proposed and evaluated in the latest decade. In this review, available studies regarding the recent development of liners are gathered.
Use combination of inlet & exhaust results with calibration liner to fine tune estimate of . Goal is to set centerline Mach and total temperature to within ±0.002 and ±0.28°C (±0.5°F) of target values.
Acoustic liners are passive devices typically mounted in the walls of aircraft inlets and aft-bypass ducts to absorb noise generated by the fan. Single-degree-of-freedom (SDOF) and two-degree-of-freedom (2DOF) perforate-over-honeycomb liners (see Figure 1) have been used on commercial aircraft since the early 1950’s [1].
Broadband and Low-Frequency Acoustic Liner Investigations at ...
2022年1月3日 · NASA and ONERA have explored a number of acoustic liner concepts over the last few decades. This paper begins with a brief review regarding conventional liners as well as the recent implementation of multi-degree-of-freedom liners enabled by embedded mesh caps.
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