Acoustic damping device for chambers with grazing flow

1. An acoustic damper comprising:

a neck and a damping volume, wherein the neck comprises a mouth being in fluid connection with a chamber, wherein adjacent to the mouth of the neck at least one opening for a sealing gas is located;

the acoustic damper configured such that the at least one opening for the sealing gas is directed into the chamber to form a windshield in the chamber such that a grazing flow of gas passing through the chamber is deflected away from the mouth so that a bias flow of gas passing through the mouth is feedable into the chamber via the mouth independent of the grazing flow; and

wherein the at least one opening for sealing gas is configured so that each of the at least one opening emits sealing gas into the chamber in a direction that is parallel to a direction at which the bias flow of gas is emitted from the mouth into the chamber and is perpendicular to the grazing flow; wherein each of the at least one opening is structured such that the sealing gas is emitted at a first velocity that is greater than a velocity of the bias flow and is also greater than a velocity of the grazing flow.

2. The damper according to of claim 1 , wherein the at least one opening for sealing gas comprises at least one opening that is located upstream of the mouth.

3. The acoustic damper of claim 1 , wherein the at least one opening comprises 3 to 8 openings that are located around the mouth of the neck.

4. The damper according to claim 1 , wherein the at least one opening for sealing gas has circular, elliptic or square cross-section.

5. The damper according to claim 1 , wherein the at least one opening for sealing gas is defined by a body of the damper to be supplied with gas from a hood of a gas turbine.

6. The damper according to claim 1 , wherein the sealing gas that flows though the at least one opening is cooling air or a mixture of burnt or unburnt air and fuel.

7. The damper according to claim 1 , wherein the damper is a Helmholtz resonator with one or more damping volumes, a half-wave tube, a quarter-wave tube, multi-volume damper, a liner or an acoustic flow through damper.

8. The damper according to claim 1 , wherein the chamber is a combustor chamber, a mixing chamber, a plenum and/or an air channel of a gas turbine.

9. A gas turbine comprising:

a combustion chamber defined by at least one wall having an inner surface;

an acoustic damper comprising a neck and a damping volume, the neck having a mouth in the inner surface of the wall in fluid communication with the combustion chamber;

the combustion chamber configured such that a grazing flow of gas is flowing inside the combustion chamber along a portion of the inner surface;

the acoustic damper defining at least one opening adjacent the mouth configured to emit a sealing gas into the chamber upstream of the mouth in a direction of flow that is transverse to a direct on of flow of the grazing flow to deflect the grazing flow away from the mouth; and

wherein the at least one opening is configured such that the sealing gas has a velocity that is greater than a velocity of the grazing flow and is greater than a velocity of a bias flow of gas that is passed through the mouth and into the combustion chamber via the acoustic damper.

10. The gas turbine of claim 9 , wherein the at least one opening adjacent the mouth is configured to emit the sealing gas into the chamber upstream of the mouth in a direction of flow that is perpendicular to the direction of flow of the grazing flow to deflect the grazing flow away from the mouth.

11. The gas turbine of claim 9 , wherein the acoustic damper is also configured to define at least one opening in the inner wall that is in fluid communication with the combustion chamber that is downstream of the mouth.

12. The gas turbine of claim 9 , wherein the at least one opening includes 3 to 8 openings.

13. The gas turbine of claim 9 , wherein the at least one opening is configured to emit the sealing gas into the combustion chamber to form a windshield such that the bias flow passing through the mouth is feedable into the chamber via the mouth independent of the grazing flow.

14. The gas turbine of claim 13 , wherein the at least one opening includes 4 to 5 openings.

15. The gas turbine of claim 13 , wherein the at least one opening includes 3 to 8 openings.

16. The gas turbine of claim 13 , comprising:

a hood, the hood being in fluid communication with the at least one opening to supply the sealing gas to the at least one opening.

17. The gas turbine of claim 13 , wherein the at least one opening has a circular cross-section, an elliptical cross-section, a polygonal cross-section, a rectangular cross-section, or a square cross-section.