Method of operating a gas turbine combustor comprising injecting a diluent into the primary and secondary combustion zones

A method of operating a gas turbine engine, the method comprising:

• flowing compressed air through a combustion chamber of a combustor in a bulk airflow direction from a forward end of the combustion chamber to an outlet of the combustion chamber;
• injecting a primary portion of a fuel into a primary combustion zone at the forward end of the combustion chamber using a primary fuel nozzle;
• injecting a primary portion of a diluent into the primary combustion zone at the forward end of the combustion chamber;
• injecting a secondary portion of the fuel into a secondary combustion zone of the combustion chamber using a secondary fuel nozzle, the secondary combustion zone being located downstream of the primary combustion zone in the bulk airflow direction;
• and
• injecting a secondary portion of the diluent into the combustion chamber,
• wherein the primary portion of the diluent being from twenty percent to eighty percent of the diluent injected into the combustion chamber over a time interval, and the secondary portion of the diluent is the remaining portion of the diluent injected into the combustion chamber over the time interval.