Engine Assembly, Acoustical Liner And Associated Method Of Fabrication

An engine assembly comprising:

• a fan;
• a compressor downstream of the fan;
• a combustor downstream of the compressor;
• a turbine downstream of the combustor;
• and
• an acoustical liner surrounding the fan, wherein the acoustical liner comprises:
• an inner barrel comprising:
• a perforated face sheet;
• a core;
• and
• a back skin disposed on the core and comprising a plurality of perforations;
• and
• an outer barrel surrounding and spaced from the inner barrel to define a fluid-filled space therebetween,
• wherein the perforations defined by the back skin place the core in fluid communication with the space between the inner and outer barrels.

A method of fabricating an acoustical liner comprising:

• providing an inner barrel comprising a perforated face sheet, a back skin and a core disposed between the perforated face sheet and the back skin;
• positioning the inner barrel within an outer barrel which surrounds and is spaced from the inner barrel to define a fluid-filled space therebetween;
• and
• tuning a natural frequency of the acoustical liner via perforation in the back skin to place the core in fluid communication with the space between the inner and outer barrels.