System and method for barrier in passage of combustor of gas turbine engine with exhaust gas recirculation

A system comprising:

• a turbine combustor comprising:
• a combustor liner disposed about a combustion chamber;
• and
• a flow sleeve disposed at an offset about the combustor liner to define a passage, wherein the passage comprises:
• an oxidant section configured to direct an oxidant in a first direction, wherein the oxidant is configured to react with a first fuel in the combustion chamber to produce combustion gases;
• a cooling section configured to direct an inert gas in a second direction substantially opposite to the first direction, wherein the inert gas is configured to cool the combustor liner and the combustion gases in the combustion chamber;
• and
• a barrier section between the oxidant section and the cooling section, wherein the barrier section is configured to substantially separate the oxidant in the oxidant section from the inert gas in the cooling section, wherein the barrier section is configured to provide a dynamic barrier comprising a fluid interface between the oxidant and the inert gas where the oxidant and the inert gas interact directly, and a position of the dynamic barrier is movable along a length of the passage;
• and
• a controller configured to control a first flow of the oxidant into the oxidant section and a second flow of the inert gas into the cooling section, wherein the controller is configured to move the dynamic barrier within the passage based at least in part on controlling the first flow, the second flow, or any combination thereof.

A method comprising:

• injecting an oxidant and a fuel into a combustion chamber from a head end of a turbine combustor;
• combusting the oxidant and the fuel in the combustion chamber to provide substantially stoichiometric combustion;
• cooling the combustion chamber with an exhaust gas flow, wherein the exhaust gas flow is directed upstream from a turbine end of the turbine combustor toward the head end along a passage disposed about the combustion chamber;
• substantially blocking the exhaust gas flow within the passage with a barrier, wherein the barrier comprises a dynamic barrier comprising a fluid interface between the oxidant from the head end and the exhaust gas flow where the oxidant and the exhaust gas flow interact, and a position of the dynamic barrier is movable along a length of the passage;
• and
• moving the dynamic barrier in the passage by controlling a portion of the oxidant in the passage, the exhaust gas flow in the passage, or any combination thereof.