Annulus filler

Abstract

An annulus filler is provided for mounting to a rotor disc of a gas turbine engine and bridging the gap between two adjacent blades attached to the rotor disc, The annulus filler has an outer lid which defines an airflow surface for air being drawn through the engine, the lid having a leading edge and a trailing edge in an axial airflow direction. The annulus filler further has a support arrangement which is connectable to the rotor disc. The support arrangement includes a first engageable portion at the leading edge of the lid and a second engageable portion at the trailing edge of the lid. The engageable portions engage in use with respective adjacent parts of the gas turbine engine, and have respective galvanic corrosion barriers, which prevent or reduce galvanic corrosion between the material of the lid and the respective adjacent engine parts.

1 . An annulus filler for mounting to a rotor disc of a gas turbine engine and bridging the gap between two adjacent blades attached to the rotor disc, the annulus filler having:
 an outer lid which defines an airflow surface for air being drawn through the engine, the lid having a leading edge and a trailing edge in an axial airflow direction; and   a support arrangement which is connectable to the rotor disc to support the lid on the rotor disc;   wherein the support arrangement includes a first engageable portion at the leading edge of the lid and a second engageable portion at the trailing edge of the lid, the engageable portions engaging in use with respective adjacent parts of the gas turbine engine, and having respective galvanic corrosion barriers which prevent or reduce galvanic corrosion between the material of the lid and the respective adjacent engine parts.   
     
     
         2 . The annulus filler of  claim 1 , wherein the adjacent engine part of the first engageable portion includes a nosecone fairing or a makeup piece of a nosecone fairing. 
     
     
         3 . The annulus filler of  claim 1 , wherein the adjacent engine part of the second engageable portion is a fan rear seal. 
     
     
         4 . The annulus filler of  claim 1  wherein the galvanic corrosion barrier of the first engageable portion has a reduced coefficient of friction relative to the lid to facilitate relative movement between the first engageable portion and the respective adjacent engine part. 
     
     
         5 . The annulus filler of  claim 1  wherein the galvanic corrosion barrier of the second engageable portion has an increased coefficient of friction relative to the lid to reduce relative movement between the second engageable portion and the respective adjacent engine part. 
     
     
         6 . The annulus filler of  claim 1  wherein the lid is substantially entirely formed from polymer matrix composite material. 
     
     
         7 . The annulus filler of  claim 1  wherein the galvanic corrosion barrier of the first engageable portion is formed from a polyimide-based plastic. 
     
     
         8 . The annulus filler of  claim 1  wherein the galvanic corrosion barrier of the second engageable portion is formed from a glass fibre reinforced composite material. 
     
     
         9 . The annulus filler of  claim 1  for mounting to a fan disc and bridging the gap between two adjacent fan blades attached to the fan disc. 
     
     
         10 . A stage for a gas turbine engine having:
 a rotor disc,   a circumferential row of spaced apart blades attached to the rotor disc, and   a plurality of annulus fillers according to  claim 1  bridging the gaps between adjacent blades.   
     
     
         11 . A gas turbine engine having the stage of  claim 10 .