Turbine engine fuel injection system and methods of assembling the same

A mixer assembly for use with a combustor of a turbine engine, the assembly comprising:

• a mixer comprising a main housing;
• and
• a fuel injection system positioned within said main housing, said fuel injection system comprising:
• a fuel injection housing radially inward of said main housing such that an annular cavity is defined therebetween said fuel injection housing having an inner wall and an outer wall, said fuel injection system in fluid communication with said annular cavity;
• a fuel manfold extending through said fuel injection housing in fluid communication with a plurality of fuel injection ports;
• and
• an air manifold defining a first plurality of air injection ports and a second plurality of air injection ports extending through said fuel injection housing from said inner wall to said outer wall,
• wherein each one of said first plurality of air injection ports is in fluid communication with a set of plurality of ports,
• wherein each of said set of plurality of ports is associated with a corresponding fuel injection port of said plurality of fuel injection ports,
• wherein each port of said set of plurality of ports is equally spaced around said outer wall forming a substantiality arcual shape having an arc center at a center point of said corresponding fuel injection port, and
• wherein the fuel injection system is positioned on an annular dome mounted upstream from a combustion chamber of the combustor.

A method of assembling a fuel injection system for use with a combustor of a turbine assembly, said method comprising:

• positioning a fuel manifold at least partially within a fuel injection housing, the fuel injection housing having an inner wall and an outer wall and at least partially defining an annular cavity radially outward and surrounding said wall;
• forming a plurality of fuel injection ports in the fuel manifold such that the fuel injection ports extend through the fuel injection housing, each fuel injection port of the plurality of fuel injection ports configured to introduce a fuel stream into the annular cavity;
• positioning an air manifold at least partially radially inward about said inner wall of the fuel injection housing;
• forming a first plurality of air injection ports in the air manifold such that the first plurality of air injection ports extend through the fuel injection housing from said inner wall to said outer wall downstream of the plurality of fuel injection ports;
• and
• forming a second plurality of air injection ports in the air manifold such that the second plurality of air injection ports extend through the fuel injection housing from said inner wall to said outer wall downstream of the first plurality of air injection ports, each air injection port of the first plurality of air injection ports and the second plurality of air injection ports is configured to introduce an air cushion into the annular cavity to facilitate film cooling of the fuel injection housings,
• wherein forming the first plurality of air injection ports comprises forming a plurality of sets of ports in fluid communication therein,
• wherein each of said set of plurality of ports is associated with a corresponding fuel injecton port of said plurality of fuel injection ports,
• wherein each port of said set of plurality of ports is equally spaced around said outer wall forming a substantially arcual shape having an arc center at a center point of said corresponding fuel injection port, and
• wherein the fuel injection system is positioned on an annular dome mounted upstream from a combustion chamber of the combustor.