Patent ID: 8202041
Filing Date: 2012-06-19
Classification: F04D,F05D

Abstract:
1. A turbofan engine comprising: a fan case surrounding a set of fan blades mounted for rotation about a central axis of the engine, the fan case having: a structurally supporting metal or composite inner shell having an axially extending wall with a radially inner side closely surrounding tips of the fan blades and defining a continuous flow boundary surface from a first location fore of the fan blades to a second location aft of the fan blades, an axially extending nesting chamber defined on a radially outer side of the axially extending wall of the structurally supporting metal or composite inner shell, said nesting chamber extending from a third location fore of the fan blades to a fourth location aft of the fan blades, wherein the axially extending wall of the structurally supporting metal or composite inner shell has axially spaced-apart regions of different wall thicknesses along a length thereof, the thickness of the axially extending wall being greater at a leading edge of the fan blades than at a trailing edge thereof; an acoustic liner filling said nesting chamber, the acoustic liner axially spanning the fan blades; a stiffening ring secured to a radially outer surface of the acoustic liner and the structurally supporting metal or composite inner shell, the stiffening ring sealing the acoustic liner in the nesting chamber; and an outer blade containment fabric layer wrapped around the stiffening ring.