Helmholtz damper and gas turbine with such a helmholtz damper

Abstract

A Helmholtz damper, especially for damping pulsations in a combustor of a gas turbine, including a damper volume, which can be connected to a damped space by means of a neck tube. The Helmholtz damper further includes a piston, which is moveable within the damper volume and divides the damper volume into a variable first part (V 1 ) on one side of said piston. The variable first part (V 1 ) is connected to the neck tube, and a correspondingly variable second part (V 2 ) on the other side of said piston. The control mechanism is substantially simplified in a more compact design by the piston being driven by a pressure drop (Δp) between the first and second part (V 1, V 2 ) of the damper volume.

1 . A Helmholtz damper, especially for damping pulsations in a combustor of a gas turbine, comprising a damper volume, which can be connected to a damped space by means of a neck tube, and further comprising a piston, which is moveable within said damper volume and divides said damper volume into a variable first part (V 1 ) on one side of said piston, which variable first part (V 1 ) is connected to said neck tube, and a correspondingly variable second part (V 2 ) on the other side of said piston, wherein said piston is driven by a pressure drop (Δp) between said first and second part (V 1 , V 2 ) of said damper volume. 
     
     
         2 . The Helmholtz damper as claimed in  claim 1 , wherein the piston is held in an idle position, where the first part (V 1 ) of said damper volume is a maximum, by means of a spring, and that said pressure drop (Δp) drives said piston against the force of said spring. 
     
     
         3 . The Helmholtz damper as claimed in  claim 2 , wherein said spring is arranged within said first part (V 1 ) of said damper volume. 
     
     
         4 . The Helmholtz damper as claimed in  claim 2 , wherein said spring is arranged outside of said damper volume and acts on said piston via a piston rod, which extends from said piston to the outside of said damper volume. 
     
     
         5 . The Helmholtz damper as claimed in  claim 2 , wherein said spring is a helical spring. 
     
     
         6 . The Helmholtz damper as claimed in  claim 1 , wherein said second part (V 2 ) of said damper volume is in fluidic connection with the outside of said damper volume. 
     
     
         7 . The Helmholtz damper as claimed in  claim 6 , wherein said damper volume is enclosed by a housing, and that said fluidic connection is established by at least one opening in said housing. 
     
     
         8 . A gas turbine comprising a compressor, at least one combustor and a turbine, whereby said at least one combustor is enclosed by a combustor casing, the outside of which is exposed to the compressor outlet pressure (pk 2 ) of said compressor, whereby at least one Helmholtz damper is provided at and connected to one combustor in order to damp pulsations within said combustor, wherein said at least one Helmholtz damper is a Helmholtz damper as claimed in  claim 1 , and that a pressure drop between said compressor outlet pressure (pk 2 ) and the pressure within said combustor is used to drive said piston of said at least one Helmholtz damper. 
     
     
         9 . The gas turbine as claimed in  claim 8 , wherein said at least one Helmholtz damper is attached to said combustor casing by adaptation means. 
     
     
         10 . The gas turbine as claimed in  claim 9 , wherein said at least one Helmholtz damper is connected to said combustor through a hole in said combustor casing, and that said adaptation means comprises an insert, which fits into said hole and receives a neck tube of said at least one Helmholtz damper such that said neck tube passes through said insert to open out into said combustor. 
     
     
         11 . The gas turbine as claimed in  claim 10 , further comprising a neck tube adapter is provided to seal said neck tube against said insert. 
     
     
         12 . The gas turbine as claimed in  claim 10 , wherein said neck tube is releasably connected to the damper volume of said at least one Helmholtz damper. 
     
     
         13 . The gas turbine as claimed in  claim 8 , wherein said combustor is of an annular configuration, and that a plurality of Helmholtz dampers are circumferentially arranged around said combustor. 
     
     
         14 . The gas turbine as claimed in  claim 8 , wherein said at least one combustor is of the can type, and that the Helmholtz damper is circumferentially arranged around the can combustor.