Combustor and Method of Operating a Combustor

Abstract

A combustor comprises in flow series a burner, a transition piece and a combustion chamber being of larger diameter than the transition piece, the combustion chamber being connected to the transition piece via a dome portion. In the dome portion are located air injection openings. A method of operating the combustor comprises the stop of introducing air from the dome portion by means of air jets.

1 .- 7 . (canceled) 
   
   
       8 . A combustor for a gas turbine, comprising:
 a burner;   a transition piece arranged downstream of and adjacent to the burner with respect to a flow direction; and   a combustion chamber arranged downstream of and adjacent to the transition piece with respect to a flow direction, wherein the combustion chamber has a greater diameter than the transition piece; and   a dome portion that connects the transition piece to the combustion chamber, the dome portion having a plurality of air injection openings comprising a first row of openings positioned on a circle of a first radius and at least one further row of openings positioned on at least one further circle of a second radius different that the first radius, wherein all of the openings have an enlarged shape with a long direction and a short direction, the long direction of the first row being oriented essentially tangential an edge of the dome and a tangential component portion of a respective opening's long direction increases with the opening being positioned nearer the innermost radius of the dome portion.   
   
   
       9 . The combustor as claimed in  claim 8 , wherein the first row of openings are arranged at a dome edge adjacent the transition piece. 
   
   
       10 . The combustor as claimed in  claim 8 , wherein the number of openings of the first row is greater than the number of openings of the further row. 
   
   
       11 . The combustor as claimed in  claim 10 , wherein the openings of the first row have a smaller diameter than a diameter of the openings of the further row. 
   
   
       12 . The combustor as claimed in  claim 11 , wherein duct portions of ducts for feeding air to openings adjoining the air injection openings have angles of inclination to the surface normal between 45 degrees and 80 degrees. 
   
   
       13 . A method of operating a combustor for a gas turbine, comprising:
 providing a burner, a transition piece arranged downstream of and adjacent to the burner with respect to a flow direction, and a combustion chamber arranged downstream of and adjacent to the transition piece with respect to a flow direction, wherein the combustion chamber has a greater diameter than the transition piece;   arranging a dome portion between the transition piece and the combustion chamber that connects the transition piece to the combustion chamber, where the dome portion has a plurality of air injection openings comprising a first row of openings positioned on a circle of a first radius and at least one further row of openings positioned on at least one further circle of a second radius different that the first radius, wherein all of the openings have an enlarged shape with a long direction and a short direction, the long direction of the first row being oriented essentially tangential an edge of the dome and a tangential component portion of a respective opening's long direction increases with the opening being positioned nearer the innermost radius of the dome portion; and   introducing air into the combustion chamber from the dome portion via air jets,
 wherein an air jet without any tangential component streams through an air injection opening of a row positioned at an outermost radius of the dome portion, and 
 wherein air jets with a tangential component that increases with decreasing radial position flow through openings of the other rows. 
   
   
   
       14 . The method as claimed in  claim 13 , wherein the air is introduced with an inclination to the surface normal of the dome portion between 45 degrees and 80 degrees. 
   
   
       15 . The method as claimed in  claim 14 , wherein the number of openings of the first row is greater than the number of openings of the further row. 
   
   
       16 . The method as claimed in  claim 15 , wherein the openings of the first row have a smaller diameter than a diameter of the openings of the further row. 
   
   
       17 . The combustor as claimed in  claim 16 , wherein the introduced air is provided via duct portions of ducts for feeding air to openings adjoining the air injection openings.