초록 ▼

An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the str

An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the structural integrity of the engine, or increasing the noise generated by the engine. The acoustical liner may have additional acoustical degrees of freedom which permit these seemingly competing concerns to be addressed in a complementary manner. The acoustical liner may include inner and outer barrels with the inner barrel having a perforated face sheet, a perforated back skin and a core disposed between the perforated face sheet and the back skin. The fluid communication between the core and the space between the inner and outer barrels provides additional acoustical degrees of freedom which may be utilized to reduce fan blade flutter while concurrently limiting fan blade noise.

대표청구항 ▼

That which is claimed: 1. An acoustical liner comprising:an inner barrel comprising:a perforated face sheet;a back skin comprising a plurality of perforations; anda core disposed between the perforated face sheet and the back skin;an outer barrel surrounding and spaced from the inner barrel to defin

That which is claimed: 1. An acoustical liner comprising:an inner barrel comprising:a perforated face sheet;a back skin comprising a plurality of perforations; anda core disposed between the perforated face sheet and the back skin;an outer barrel surrounding and spaced from the inner barrel to define a fluid-filled space therebetween; andend members configured to confine fluid contained between the inner and outer barrels to define the space between the inner and outer barrels,wherein perforations in the face sheet and a volume of fluid contained in the core provide one or more acoustical degrees of freedom,wherein the perforations defined by the back skin place the core in fluid communication with the space between the inner and outer barrels, said perforations in the back skin providing one or more additional acoustical degrees of freedom having acoustical inertia due to a thickness of the back skin in which the perforations are defined and an acoustical compliance due to the fluid communication with the space between the inner and outer barrels, andwherein the inner and outer barrels are configured to have at least one natural frequency within a first frequency range associated with fan blade flutter and at least one natural frequency within a second frequency range, different than the first frequency range, associated with fan noise at fan blade-pass frequencies.