Damping device for a combustor of a gas turbine

Abstract

The present invention relates to a damping device for a combustor of a gas turbine for suppressing combustion instabilities. More specifically, the invention relates to a design of a broadband damping device for a low emission combustor having at least one resonator for damping pressure fluctuations in the combustion chamber. It is an object of the invention to provide a damping device with a quarter wave damper having broadband characteristics. The damping device for a combustor of a gas turbine according to the invention comprises a casing defining a resonator volume, a hole at a front face of the casing for allowing fluid communication between the resonator volume and the combustion chamber, the casing having parameters such that it acts as a quarter wave damper, is characterized in that the resonator volume is limited by a rear face and at least one lateral surface of the casing, whereby at least one lateral surface is equipped with one or more cavities inside and the rear face is equipped with at least one feed hole for feeding a purging fluid into the resonator volume. The preferably groove-shaped side cavities initiate energy dissipating vertical flows.

1 . A damping device for a combustor of a gas turbine for suppressing combustion instabilities in a combustion chamber, comprising a liner extending from an upstream end downwardly around the combustion chamber, at least one acoustic damper provided along the liner and/or a supply line for fuel or air to the combustion chamber, the acoustic damper comprising a casing defining a resonator volume, a hole at a front face of the casing for allowing fluid communication between the resonator volume and the combustion chamber, the casing having parameters such that it acts as a quarter wave damper, wherein the resonator volume is limited by a rear face and at least one lateral surface of the casing, whereby at least one lateral surface is equipped with one or more cavities and the rear face is equipped with at least one feed hole for feeding a purging fluid into the resonator volume. 
     
     
         2 . The damping device according to  claim 1 , wherein at least one of the cavities is groove-shaped. 
     
     
         3 . The damping device according to  claim 2 , wherein at least one cavity runs circumferentially around the lateral surface. 
     
     
         4 . The damping device according to  claim 3 , wherein two or more rows of circumferentially running cavities are arranged consecutively in a longitudinal direction of the casing. 
     
     
         5 . The damping device according to  claim 2 , wherein the casing is equipped with at least one corrugated lateral surface. 
     
     
         6 . The damping device according to  claim 1 , wherein the casing is a tube. 
     
     
         7 . The damping device according to  claim 1 , wherein the casing has a circular or elliptic cross section. 
     
     
         8 . The damping device according to  claim 1 , wherein the casing has a polygonal, particularly rectangular cross section. 
     
     
         9 . The damping device according to  claim 8 , further comprising at least a first lateral surface equipped with one or more side cavities, whereas at least a second lateral surface is even. 
     
     
         10 . The damping device according to  claim 1 , further comprising a longitudinal axis of the damper casing possesses an orientation orthogonally or essentially orthogonally to the outer surface of the combustor liner. 
     
     
         11 . The damping device according to  claim 1 , wherein the longitudinal axis of the damper casing possesses an inclined orientation to the outer surface of the combustor liner. 
     
     
         12 . The damping device according to  claim 1 , wherein the longitudinal axis of the damper casing is arranged parallel to the outer surface of the liner. 
     
     
         13 . The damping device according to  claim 1 , wherein the quarter wave damper is coupled to an air supply line. 
     
     
         14 . The damping device according to  claim 1 , wherein the quarter wave damper is coupled to a can combustor. 
     
     
         15 . The damping device according to  claim 1 , wherein the quarter wave damper is coupled to an annular combustion chamber. 
     
     
         16 . A combustor for a gas turbine, disposed downstream from a compressor and upstream from a turbine, said combustor comprising at least one burner at an upstream end, configured to inject a fuel and/or air or a fuel/air mixture into a combustion chamber, a liner extending from the upstream end downwardly around the combustion chamber, wherein the combustor additionally comprises at least one quarter wave damper according to  claim 1  for suppressing combustion instabilities in the combustion chamber. 
     
     
         17 . The combustor according to  claim 16 , further comprising at least two quarter wave dampers disposed circumferentially around the combustor liner. 
     
     
         18 . The combustor according to  claim 16 , further comprising at least two quarter wave dampers disposed in different longitudinal positions of the combustor. 
     
     
         19 . The combustor according to  claim 16 , wherein at least one of the quarter wave dampers is folded around the combustor liner. 
     
     
         20 . The combustor according to  claim 19 , wherein at least one of the dampers is folded in circumferential direction with respect to the combustor liner. 
     
     
         21 . The combustor according to  claim 19 , wherein at least one of the dampers is folded in longitudinal direction with respect to the combustor liner. 
     
     
         22 . The combustor according to  claim 16 , wherein the combustor is a can combustor of a stationary gas turbine. 
     
     
         23 . The combustor according to  claim 16 , wherein the combustor is an annular combustion chamber of a stationary gas turbine. 
     
     
         24 . The combustor according to  claim 16 , further comprising a number of quarter wave dampers of different geometry is coupled to the liner. 
     
     
         25 . The combustor according to  claim 24 , further comprising quarter wave dampers of different lengths are coupled to the liner.