Blisk

Abstract

A blisk has a rotor disk part and a circumferential row of blades extending from and integral with the disk part. A plurality of annulus fillers is provided to bridge the gaps between adjacent blades. Each annulus filler has an outer lid which defines an airflow surface for air being drawn through the engine in an axial airflow direction, and an inner support structure which connects to the disk part to support the lid on the blisk. Opposite edges of the lid make respective lines of contact with a suction side of one blade and a pressure side of an adjacent blade.

1 . A blisk for a gas turbine engine, the blisk having a rotor disk part, a circumferential row of blades extending from and integral with the disk part, and a plurality of annulus fillers bridging the gaps between adjacent blades;
 wherein each annulus filler has an outer lid which defines an airflow surface for air being drawn through the engine in an axial airflow direction, and an inner support structure which connects to the disk part to support the lid on the blisk, opposite edges of the lid making respective lines of contact with a suction side aerofoil surface of one blade and a pressure side aerofoil surface of an adjacent blade.   
     
     
         2 . A blisk according to  claim 1 , wherein the suction side and pressure side aerofoil surfaces of each blade continue radially inwardly of the respective lines of contact such that if the lids are moved radially inwardly, all the regions of suction and pressure side surfaces of the blades thereby revealed radially outwardly of the lids are aerofoil surface regions. 
     
     
         3 . A blisk according to  claim 1 , wherein the lid of each annulus filler has damping strips which extend along the opposite edges of the lid to contact the suction and pressure sides of the adjacent blades. 
     
     
         4 . A blisk according to  claim 1 , wherein the support structure of each annulus filler provides beneath the lid one or more retention formations which each retains a respective hook formed at the outer surface of the disk part and thereby holds the filler in position between its adjacent blades under centrifugal loading. 
     
     
         5 . A blisk according to  claim 4 , wherein the retention formations and hooks are formed such that, on build, the annulus filler can be slid axially into position between its adjacent blades to mate the hooks with the retention formations. 
     
     
         6 . A blisk according to  claim 4 , wherein damping pads are located at the interfaces between the retention formations and hooks. 
     
     
         7 . A blisk according to  claim 1 , wherein the support structure of each annulus filler provides a front and/or rear engagement formation at the front and/or rear end of the lid, the engagement formation engaging with a respective engine component to axially hold the filler in position between its adjacent blades. 
     
     
         8 . A blisk according to  claim 1 , wherein the annulus filler is formed from aluminium alloy, titanium alloy, composite material or a combination thereof. 
     
     
         9 . A blisk according to  claim 1 , wherein the blades are welded to the disk part. 
     
     
         10 . A gas turbine engine comprising a blisk, the blisk having a rotor disk part, a circumferential row of blades extending from and integral with the disk part, and a plurality of annulus fillers bridging the gaps between adjacent blades;
 wherein each annulus filler has an outer lid which defines an airflow surface for air being drawn through the engine in an axial airflow direction, and an inner support structure which connects to the disk part to support the lid on the blisk, opposite edges of the lid making respective lines of contact with a suction side aerofoil surface of one blade and a pressure side aerofoil surface of an adjacent blade.