초록 ▼

A fan casing for a gas turbine engine is provided which combines the functions of blade containment and noise suppression. The fan casing has an annular metallic inner shell with a plurality of holes are formed therethrough. An acoustic absorber, such as a cellular resonator, is disposed around the

A fan casing for a gas turbine engine is provided which combines the functions of blade containment and noise suppression. The fan casing has an annular metallic inner shell with a plurality of holes are formed therethrough. An acoustic absorber, such as a cellular resonator, is disposed around the inner shell.

대표청구항 ▼

1. A fan casing comprising: an annular metallic inner shell having forward, middle, and aft sections, said forward and aft sections having an increased thickness relative to that of said middle section, wherein a plurality of holes are formed through said forward and aft sections; an annular out

1. A fan casing comprising: an annular metallic inner shell having forward, middle, and aft sections, said forward and aft sections having an increased thickness relative to that of said middle section, wherein a plurality of holes are formed through said forward and aft sections; an annular outer shell surrounding and spaced apart from said inner shell so as to define a circumferentially extending cavity; and an acoustic absorber disposed around said inner shell. 2. The fan casing of claim 1 wherein said acoustic absorber comprises an annular first layer of cellular material disposed around said inner shell. 3. The fan casing of claim 2 further comprising an annular septum disposed around said first layer of cellular material. 4. The fan casing of claim 3 further comprising an annular second layer of cellular material disposed around said septum, wherein said septum is perforated. 5. The fan casing of claim 1 further comprising at least one layer of a ballistic material disposed around said outer shell. 6. The fan casing of claim 1 wherein a plurality of holes are formed in said middle section of said inner shell. 7. A fan assembly comprising: a plurality of blades mounted to a disk rotatable about an axis; an annular metallic inner shell surrounding said plurality of blades, said inner shell having a thickness sufficient to resist penetration by a blade released from said disk, wherein a plurality of holes are formed through said inner shell; an annular outer shell surrounding and spaced apart from said inner shell so as to define a circumferentially-extending cavity; and an acoustic absorber disposed around said inner shell. 8. The fan casing of claim 7 wherein said acoustic absorber comprises an annular first layer of cellular material disposed around said inner shell. 9. The fan casing of claim 8 further comprising an annular septum disposed around said first layer of cellular material. 10. The fan casing of claim 9 further comprising an annular second layer of cellular material disposed around said septum, wherein said septum is perforated. 11. The fan casing of claim 7 further comprising at least one layer of a ballistic material disposed around said outer shell. 12. The fan casing of claim 7 wherein a plurality of holes are formed in said middle section of said inner shell.