System and method for conditioning a working fluid in a combustor

A system for conditioning a working fluid in a combustor, comprising:

• a. a liner having an upstream end and a downstream end;
• b. a transition piece extending from the downstream end of the liner;
• c. a primary combustion chamber defined at least in part by the liner and the transition piece, wherein the primary combustion chamber includes at least one primary fuel nozzle;
• d. at least one secondary combustion chamber located upstream from the at least one primary fuel nozzle, wherein each secondary combustion chamber comprises:
• i. a shroud, wherein the shroud defines a fluid passage having a centerline through the secondary combustion chamber;
• ii. a secondary fuel nozzle at an upstream portion of the shroud;
• and
• iii. an igniter assembly installed in the secondary combustion chamber;
• wherein the at least one secondary combustion chamber and the centerline are located in an annular passage surrounding the primary combustion chamber.

A method for conditioning a working fluid in a combustor, comprising:

• a. flowing the working fluid through a primary fuel nozzle in fluid communication with a primary combustion chamber;
• b. flowing at least a portion of the working fluid through a secondary combustion chamber located upstream from the primary fuel nozzle and outside of a liner surrounding the primary combustion chamber, wherein the secondary combustion chamber comprises a shroud defining a fluid passage having a centerline through the secondary combustion chamber and wherein the secondary combustion chamber and the centerline are located in an annular passage surrounding the primary combustion chamber;
• c. flowing a fuel through the secondary combustion chamber;
• d. combusting the fuel in the secondary combustion chamber to produce combustion gases;
• and
• e. flowing the combustion gases from the secondary combustion chamber into the primary combustion chamber.