Fuel nozzle assembly for use in turbine engines and methods of assembling same

A combustor assembly for use with a turbine engine, said combustor assembly comprising:

• a casing comprising an air plenum;
• a combustor liner positioned within said casing and defining a combustion chamber therein;
• and
• a plurality of fuel nozzles coupled to said combustor liner, each fuel nozzle of said plurality of fuel nozzles comprising:
• a housing coupled to said combustor liner, said housing comprising an endwall that at least partially defines the combustion chamber;
• and
• a plurality of mixing tubes extending through said housing for channeling fuel to the combustion chamber, each mixing tube of said plurality of mixing tubes comprising an inner surface extending between an inlet portion and an outlet portion, wherein a fuel aperture extends through said inner surface proximate said inlet portion and is configured to channel a flow of fuel to said mixing tube, said outlet portion oriented adjacent said housing endwall, at least one mixing tube of said plurality of mixing tubes comprising:
• a plurality of projections extending outwardly from a distal end of said outlet portion, wherein adjacent said projections are spaced a circumferential distance apart such that a groove is defined between each of said pairs of circumferentially-apart projections to facilitate enhanced mixing of fuel in the combustion chamber, and wherein each projection of said plurality of projections comprises one of the following:
• (i) a tip surface substantially perpendicular to said inner surface, the tip surface having a substantially trapezoidal shape;
• (ii) a tip surface that extends obliquely between said inner surface and an outer surface of said at least one of said plurality of mixing tubes;
• and
• (iii) a tip surface that extends between said inner surface and an outer surface of said at least one of said plurality of mixing tubes and has an arcuate shape.

A method of assembling a fuel nozzle for use with a turbine engine, said method comprising:

• coupling a housing to a combustor liner defining a combustion chamber, the housing including an endwall that at least partially defines the combustion chamber;
• coupling a plurality of mixing tubes to the housing for channeling fuel to the combustion chamber, each mixing tube of the plurality of mixing tubes includes an inner surface that extends between an inlet portion and an outlet portion, wherein a fuel aperture extends through said inner surface proximate said inlet portion and is configured to channel a flow of fuel to said mixing tube, and wherein the outlet portion is positioned adjacent the housing endwall;
• forming at least one groove through the outlet portion of at least one mixing tube of the plurality of mixing tubes such that a plurality of circumferentially-spaced projections extend outwardly from a distal end of the outlet portion to facilitate enhanced mixing of fuel in the combustion chamber, wherein each projection of said plurality of projections comprises one of the following:
• (i) a tip surface substantially perpendicular to said inner surface, the tip surface having a substantially trapezoidal shape;
• (ii) a tip surface that extends obliquely between said inner surface and an outer surface of said at least one of said plurality of mixing tubes;
• and
• (iii) a tip surface that extends between said inner surface and an outer surface of said at least one of said plurality of mixing tubes and has an arcuate shape.