Fuel injector with premix pilot nozzle

A fuel injector for a gas turbine engine, comprising:

• a. an axially elongating peripheral wall defining an outer envelope of the injector, the wall having an interior surface defining an axially elongating interior cavity;
• b. a center body disposed within the axially elongating interior cavity, the center body defined by an exterior wall, wherein the exterior wall includes an upstream end and a downstream end disposed axially opposite the upstream end, the exterior wall concentrically arranged about a longitudinal axis of the axially elongating peripheral wall, wherein the exterior wall defines a hollow axially elongating interior passage radially inward of the exterior wall through which air flows from the upstream end to the downstream end, and wherein the center body and the axially elongating peripheral wall define a primary air flow channel therebetween;
• c. a fuel pipe positioned within the center body, extending axially from the upstream end to the downstream end of the center body, the fuel pipe defining a fuel passage disposed radially outward from the longitudinal axis of the axially elongating peripheral wall, the fuel pipe configured in fluid connection to a source of fuel;
• d. a swozzle including a plurality of swirler vanes extending radially across the primary air flow channel, at least one of the swirler vanes including a radial air supply tube, the radial air supply tube defining an auxiliary air passage through which air from a head end volume enters the axially elongating interior passage, and at least one of the swirler vanes defining at least one fuel outlet opening configured and disposed in fluid communication with the primary air flow channel;
• and
• e. a premix nozzle positioned at the downstream end of the center body, the premix pilot nozzle defining a circumferentially extending fuel plenum at an upstream end of the premix pilot nozzle, the fuel passage in fluid communication with the fuel plenum, the premix pilot nozzle defining a plurality of axially extending premix passages in fluid communication with the fuel plenum and defining a plurality of exit openings at a downstream end of the premix pilot nozzle, the premix pilot nozzle defining at least one fill opening at the upstream end of the premix pilot nozzle, the at least one fill opening communicating a fluid from the interior passage to the plurality of premix passages, the premix pilot nozzle defining an outlet at the downstream end of the premix pilot nozzle, and wherein the premix pilot nozzle defines an axially extending inner channel radially inward of the fuel pipe extending upstream from the outlet to the downstream end of the interior passage.