Annulus filler system

Abstract

An annulus filler system bridges the gap between two adjacent blades attached to a rim of the rotor disc of a gas turbine engine. The system includes an annulus filler having a lid which extends between the adjacent blades and defines an airflow surface for air being drawn through the engine. The filler also has a support body extending beneath the lid and terminating in an elongate foot which, in use, extends along a groove provided in the rim of the disc. The groove has a neck which prevents withdrawal of the foot through the neck in a radially outward direction of the disc. The system further includes a sleeve which, after installation of the filler, is slidably locatable into a gap between the foot and sides of the groove.

1 . An annulus filler system bridging the gap between two adjacent blades attached to a rim of the rotor disc of a gas turbine engine, the system including:
 an annulus filler having a lid which extends between the adjacent blades and defines an airflow surface for air being drawn through the engine, and a support body extending beneath the lid and terminating in an elongate foot which, in use, extends along a groove provided in the rim of the disc, the groove having a neck which prevents withdrawal of the foot through the neck in a radially outward direction of the disc, and   a sleeve which, after installation of the filler, is slidably locatable into a gap between the foot and sides of the groove;   wherein the foot is formed of composite material and the sleeve provides a galvanic isolation layer preventing galvanic corrosion between the foot and the disc.   
     
     
         2 . An annulus filler system according to  claim 1 , wherein the composite material comprises carbon fibres. 
     
     
         3 . An annulus filler system according to  claim 1 , wherein the galvanic isolation layer is selected from the group consisting of: a layer of glass fibre in a non-conductive matrix; a glass layer formed or fused onto the surface of the sleeve; and a paint layer or coating. 
     
     
         4 . An annulus filler system according to  claim 1 , wherein the sleeve has a layer of ballotinis within the galvanic isolation layer. 
     
     
         5 . An annulus filler according to  claim 3 , wherein the sleeve has a layer of ballotinis within the galvanic isolation layer. 
     
     
         6 . An annulus filler system according to  claim 4 , wherein the layer of ballotinis are at the inner surface of the sleeve and contact, in use, the foot. 
     
     
         7 . An annulus filler system according to  claim 4 , wherein the ballotinis are embedded in an adhesive or resin. 
     
     
         8 . An annulus filler system according to  claim 1 , wherein the sleeve has an anti-frettage coating at its outer surface, the anti-frettage coating contacting, in use, the disc. 
     
     
         9 . An annulus filler system according to  claim 1 , wherein the sleeve has a metallic main body with the galvanic isolation layer on the inner surface of the sleeve. 
     
     
         10 . An annulus filler system according to  claim 1 , wherein the lid is formed from fibre-reinforced plastic. 
     
     
         11 . An annulus filler system bridging the gap between two adjacent blades attached to a rim of the rotor disc of a gas turbine engine, the system including:
 an annulus filler having a lid which extends between the adjacent blades and defines an airflow surface for air being drawn through the engine, and a support body extending beneath the lid and terminating in an elongate foot which, in use, extends along a groove provided in the rim of the disc, the groove having a neck which prevents withdrawal of the foot through the neck in a radially outward direction of the disc, and   a sleeve which, after installation of the filler, is slidably locatable into a gap between the foot and sides of the groove;   wherein the foot is formed of composite material and the sleeve provides a galvanic isolation layer preventing galvanic corrosion between the foot and the disc, wherein the composite material comprises carbon fibres; wherein the galvanic isolation layer is selected from the group comprising: a layer of glass fibre in a non-conductive matrix; a glass layer formed or fused onto the surface of the sleeve; or a paint layer or coating.   
     
     
         12 . An annulus filler system according to  claim 11 , wherein the sleeve has a layer of ballotinis within the galvanic isolation layer. 
     
     
         13 . An annulus filler system according to  claim 12 , wherein the layer of ballotinis are at the inner surface of the sleeve and contact, in use, the foot. 
     
     
         14 . An annulus filler system according to  claim 12 , wherein the ballotinis are embedded in an adhesive or resin. 
     
     
         15 . An annulus filler system according to  claim 11 , wherein the sleeve has an anti-frettage coating at its outer surface, the anti-frettage coating contacting, in use, the disc. 
     
     
         16 . An annulus filler system according to  claim 11 , wherein the sleeve has a metallic main body with the galvanic isolation layer on the inner surface of the sleeve. 
     
     
         17 . A rotor assembly for a gas turbine engine including:
 a rotor disc,   a plurality of blades attached to a rim of the disc of a gas turbine engine, and   annulus filler systems according to  claim 1  bridging the gaps between adjacent blades;   wherein respective grooves are provided in the rim, the feet of the annulus fillers extending along the grooves, and the sleeves being located in the gaps between the feet and the sides of the grooves.   
     
     
         18 . A rotor assembly for a gas turbine engine including:
 a rotor disc,   a plurality of blades attached to a rim of the disc of a gas turbine engine, and   annulus filler systems according to  claim 11  bridging the gaps between adjacent blades;   wherein respective grooves are provided in the rim, the feet of the annulus fillers extending along the grooves, and the sleeves being located in the gaps between the feet and the sides of the grooves.