Engine casing assembly

Abstract

A gas turbine engine casing assembly has a first casing element which is located radially outward of one or more rotating aerofoil elements of the gas turbine engine. The first casing element is radially enclosed by a track element, a septum layer, a second casing element and a fan case. The track element is formed from an abrasion resistant material in order to prevent abrasion of the septum layer during excoriation of the first casing element.

1 . A gas turbine engine casing assembly, comprising:
 a first casing element located radially outward of one or more rotating aerofoil elements of the gas turbine engine;   a second casing element located radially outward of the first casing element; and   a septum layer interposed between the first casing element and the second casing element;   wherein a track element is interposed between the first casing element and the septum layer,   the track element being adapted to prevent abrasion of the septum layer during excoriation of the first casing element.   
     
     
         2 . The gas turbine engine casing assembly as claimed in  claim 1 , wherein the track element is formed from a sheet material selected from the group comprising metals and metal alloys. 
     
     
         3 . The gas turbine engine casing assembly as claimed in  claim 1 , the casing assembly having a longitudinal axis,
 wherein the track element extends along the longitudinal axis, the track element having a first end portion and a second end portion with the first casing element being received between the first end portion and the second end portion.   
     
     
         4 . The gas turbine engine casing assembly as claimed in  claim 3 , wherein each of the first end portion and the second end portion extends radially inwardly to a radially inward surface of the first casing element to form a contiguous gas-washed surface therewith. 
     
     
         5 . The gas turbine engine casing assembly as claimed in  claim 3 , wherein each of the first end portion and the second end portion is formed with a serpentine profile having a radially inwardly curved section and a radially outwardly curved section. 
     
     
         6 . The gas turbine engine casing assembly as claimed in  claim 3 , wherein each of the first end portion and the second end portion is formed as a radially inwardly projecting lip. 
     
     
         7 . The gas turbine engine casing assembly as claimed in  claim 1 , wherein the track element is bonded to the septum layer. 
     
     
         8 . The gas turbine engine casing assembly as claimed in  claim 1 , wherein the track element is bonded to the first casing element. 
     
     
         9 . The gas turbine engine casing assembly as claimed in  claim 1 , wherein the track element is formed as an integral annular ring. 
     
     
         10 . The gas turbine engine casing assembly as claimed in  claim 1 , wherein the track element is formed as a plurality of co-operating segments. 
     
     
         11 . A gas turbine fan casing comprising the gas turbine engine casing assembly as claimed in  claim 1 . 
     
     
         12 . A gas turbine engine comprising a gas turbine engine casing assembly as claimed in  claim 1 .