Aerofoil structure

Abstract

An aerofoil structure ( 2 ) comprising: a cavity ( 12 ), the cavity ( 12 ) having a viscoelastic material ( 14 ) disposed therein; and a temperature regulating means ( 16 ) for regulating the temperature of the viscoelastic material ( 14 ).

1 . An aerofoil structure comprising:
 a cavity, the cavity having a viscoelastic material disposed therein, wherein the structure comprises a temperature regulator for regulating the temperature of the viscoelastic material.   
     
     
         2 . An aerofoil structure as claimed in  claim 1 , wherein the temperature regulator comprises a bleed air system. 
     
     
         3 . An aerofoil structure as claimed in  claim 2 , wherein the bleed air system comprises one or more tubes which pass through the cavity and which are fluidically coupled to the exterior of the aerofoil structure. 
     
     
         4 . An aerofoil structure as claimed in  claim 2 , wherein the one or more tubes are surrounded by the viscoelastic material. 
     
     
         5 . An aerofoil structure as claimed in  claim 2 , wherein the one or more tubes are titanium or carbon fibre tubes. 
     
     
         6 . An aerofoil structure as claimed in  claim 2 , wherein the one or more tubes receive bleed air from a later compressor stage to heat the viscoelastic material and/or from a pre-compressor stage to cool the viscoelastic material. 
     
     
         7 . An aerofoil structure as claimed in  claim 6 , wherein the bleed air exits the one or more tubes through one or more holes in a tip or leading or trailing edge of the aerofoil structure. 
     
     
         8 . An aerofoil structure as claimed in  claim 3 , wherein the temperature regulator comprises a heating element. 
     
     
         9 . An aerofoil structure as claimed in  claim 1 , wherein the temperature regulator comprises a heating element. 
     
     
         10 . An aerofoil structure as claimed in  claim 9 , wherein the heating element is an electrical ceramic heating panel. 
     
     
         11 . An aerofoil structure as claimed in  claim 9 , wherein the heating element is disposed within the cavity. 
     
     
         12 . An aerofoil structure as claimed in  claim 9 , wherein the heating element is embedded in the viscoelastic material. 
     
     
         13 . An aerofoil structure as claimed in  claim 9 , wherein the temperature regulator maintains the viscoelastic material at an optimum damping temperature. 
     
     
         14 . An aerofoil structure as claimed in  claim 13 , wherein the optimum damping temperature is a glass transition temperature so that the viscoelastic material is in a transitional region between a glassy state and a rubbery state. 
     
     
         15 . An aerofoil structure as claimed in  claim 1 , wherein the temperature regulator maintains the viscoelastic material at an optimum damping temperature. 
     
     
         16 . An aerofoil structure as claimed in  claim 15 , wherein the optimum damping temperature is a glass transition temperature so that the viscoelastic material is in a transitional region between a glassy state and a rubbery state. 
     
     
         17 . A turbomachine having an aerofoil structure as claimed in  claim 1 .