Multitube pilot injector having a split airflow for a gas turbine engine

An injector for a combustor of a gas turbine engine comprising:

• a plurality of air/fuel mixing tubes including a radially outer subset of air/fuel mixing tubes and a radially inner subset of air/fuel mixing tubes,
• wherein each air/fuel mixing tube of the radially outer subset of air/fuel mixing tubes includes a substantially quadrilateral cross-sectional profile, and
• wherein each air/fuel mixing tube of the radially inner subset of air/fuel mixing tubes includes a substantially circular cross-sectional profile;
• a first fuel manifold in fluid communication with the radially outer subset of air/fuel mixing tubes;
• a second fuel manifold in fluid communication with the radially inner subset of air/fuel mixing tubes;
• and
• a third fuel manifold and a radially intermediate subset of the air/fuel mixing tubes,
• wherein the first fuel manifold is in fluid communication with each of the radially outer, radially intermediate, and radially inner subsets of air/fuel mixing tubes, the second fuel manifold is in fluid communication with only the radially inner subset of air/fuel mixing tubes, and the third fuel manifold is in fluid communication with only the radially inner and the radially intermediate subsets of air/fuel mixing tubes.

A combustor for a gas turbine engine and comprising:

• a generally cylindrical flow sleeve;
• a generally cylindrical combustion liner positioned radially inward from the generally cylindrical flow sleeve and defining a combustion zone;
• a first injector that is generally annularly shaped and surrounds the generally cylindrical combustion liner and is positioned at a downstream end of the generally cylindrical flow sleeve, the first injector comprising:
• radially outward openings to allow passage of compressed air following a radially outward path;
• radially inward openings to allow passage of the compressed air following a radially inward path;
• and
• a second injector that is positioned radially inward of the generally cylindrical combustion liner at an inlet end of the combustion zone to receive the compressed air from the radially outward openings in the first injector following the radially outward path, the second injector comprising:
• a plurality of air/fuel mixing tubes including a radially outer subset of air/fuel mixing tubes and a radially inner subset of air/fuel mixing tubes;
• wherein each air/fuel mixing tube of the radially outer subset of air/fuel mixing tubes includes a substantially quadrilateral cross-sectional profile, and
• wherein each air/fuel mixing tube of the radially inner subset of air/fuel mixing tubes includes a substantially circular cross-sectional profile;
• a first fuel manifold in fluid communication with the radially outer subset of air/fuel mixing tubes;
• a second fuel manifold in fluid communication with the radially inner subset of air/fuel mixing tubes;
• and
• a plurality of static air plenums, each static air plenum surrounding a corresponding one of the plurality of air/fuel mixing tubes such that each of the plurality of air/fuel mixing tubes is thermally isolated from one of the first or second fuel manifold via a corresponding static air plenum,
• wherein each of the air/fuel mixing tube of the radially outer subset of air/fuel mixing tubes includes a blocker at an outlet of each air/fuel mixing tube of the radially outer subset of air/fuel mixing tubes,
• wherein four neighboring blockers are provided proximate one another to form a substantially circular flame anchoring surface.