Gas turbine transition duct with late lean injection having reduced combustion residence time

Abstract

An improved combustion system having a reduced combustion residence time in a combustion turbine engine is provided. The combustor system may include a flow-accelerating structure ( 16, 51 ) having an inlet ( 26 ) and an outlet ( 28 ). The inlet of the flow-accelerating structure is fluidly coupled to receive a flow of combustion gases from a combustor outlet. At least one fuel injector ( 32, 64, 66 ) is disposed between the inlet and the outlet of the flow-accelerating structure. The flow-accelerating structure causes an increasing speed to the flow of combustion gases, and, as a result, the flow of combustion gases in the flow-accelerating structure experiences a decreased static temperature and a reduced combustion residence time, each of which is effective to reduce NOx emissions at the high firing temperatures of the turbine engine.

1 - 20 . (canceled) 
     
     
         21 . A combustion system comprising:
 a flow-accelerating structure defining a flow-accelerating cone between an inlet and an outlet of the flow-accelerating structure, the inlet of the flow-accelerating structure fluidly coupled to receive a flow of combustion gases from a combustor outlet; and   at least one fuel injector disposed between the inlet and the outlet of the flow-accelerating structure, wherein the flow-accelerating structure causes an increasing speed to the flow of combustion gases, and, as a result, the flow of combustion gases in the flow-accelerating structure experiences a decreased static temperature and a reduced combustion residence time, wherein a circular cross-sectional profile of the flow-accelerating cone narrows in diameter as the flow of combustion gases travels between inlet and outlet.   
     
     
         22 . The combustion system of  claim 21 , wherein the flow-accelerating structure comprises a single-piece flow-accelerating cone. 
     
     
         23 . The combustion system of  claim 21 , wherein the flow-accelerating cone comprises two interconnected cone sections. 
     
     
         24 . The combustion system of  claim 23 , wherein a portion of the two interconnected cone sections comprises a non-varying cross-sectional profile. 
     
     
         25 . The combustion system of  claim 24 , wherein said at least one fuel injector is disposed in the portion having the non-varying cross-sectional profile. 
     
     
         26 . The combustion system of  claim 21 , wherein said at least one fuel injector is arranged to provide jet in cross-flow injection. 
     
     
         27 . The combustion system of  claim 21 , wherein said at least one fuel injector is arranged without providing jet in cross-flow injection. 
     
     
         28 . The combustion system of  claim 21 , wherein the outlet of the flow-accelerating structure is fluidly coupled to supply the flow of combustion gases to a turbine section of a turbine engine. 
     
     
         29 . The combustion system of  claim 28 , wherein the flow-accelerating structure is part of a ducting arrangement configured to supply the flow of combustion gases to the turbine section of a turbine engine without a first stage of flow-directing vanes in the turbine section of the turbine engine. 
     
     
         30 . A gas turbine engine comprising:
 a combustion system comprising a ducting arrangement having a plurality of flow paths, each flow path arranged to receive a flow of combustion gases from a combustor outlet and to supply the flow of combustion gases to a turbine section of the gas turbine engine;   each flow path comprising a flow-accelerating structure defining a flow-accelerating cone between an inlet and an outlet of the flow-accelerating structure, the inlet of the flow-accelerating structure fluidly coupled to receive the flow of combustion gases from the combustor outlet; and   at least one fuel injector disposed between the inlet and the outlet of the flow-accelerating structure, wherein the flow-accelerating structure causes an increasing speed to the flow of combustion gases, and, as a result, the flow of combustion gases in the flow-accelerating structure experiences a decreased static temperature and a reduced combustion residence time in the flow paths, wherein a circular cross-sectional profile of the flow-accelerating cone narrows in diameter as the flow of combustion gases travels between inlet and outlet.   
     
     
         31 . The gas turbine engine of  claim 30 , wherein the flow-accelerating structure comprises a single-piece cone. 
     
     
         32 . The gas turbine engine of  claim 30 , wherein the flow-accelerating cone comprises two interconnected cone sections. 
     
     
         33 . The gas turbine engine of  claim 32 , wherein a portion of the two interconnected cone sections comprises a non-varying cross-sectional profile, and further wherein said at least one fuel injector is disposed in the portion having the non-varying cross-sectional profile. 
     
     
         34 . The gas turbine engine of  claim 30 , wherein said at least one fuel injector is arranged to provide jet in cross-flow injection. 
     
     
         35 . The gas turbine engine of  claim 30 , wherein said at least one fuel injector is arranged without having to provide jet in cross-flow injection. 
     
     
         36 . The gas turbine engine of  claim 30 , wherein the ducting arrangement is configured to supply the flow of combustion gases to the turbine section of the turbine engine without a first stage of flow-directing vanes.