Gas turbine engine including hydrogen-compatible fuel-air mixer with multi-jet mixing tube

A gas turbine engine, comprising:

• a compressor section, a combustion section, and a turbine section in a serial flow arrangement, with the combustion section comprising:
• a combustor liner that at least partially defines a combustion chamber;
• and
• a fuel-air mixer configured to mix gaseous fuel including hydrogen fuel and being fluidly coupled with the combustion chamber, the fuel-air mixer comprising:
• a mixing tube defining a mixing channel including a mixing tube inlet, a mixing tube outlet fluidly coupled with the combustion chamber, and a mixing channel centerline, the mixing tube inlet including a fuel inlet to receive fuel and an air inlet to receive air;
• a first set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the mixing tube inlet;
• and
• a second set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the first set of air jets, the second set of air jets circumferentially offset from the first set of air jets;
• and
• a third set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the second set of air jets;
• wherein at least one of the first set of air jets, the second set of air jets, or the third set of air jets is tangentially arranged relative to the mixing channel centerline to introduce or increase a swirl of fuel and air in the mixing channel, and at least one other of the first set of air jets, the second set of air jets, or the third set of air jets are radially arranged relative to the mixing channel centerline to increase a spread of fuel in the mixing channel, and
• wherein the first set of air jets are circumferentially offset from the second set of air jets by at least 60 degrees and less than or equal to 90 degrees.

A gas turbine engine, comprising:

• a compressor section, a combustion section, and a turbine section in a serial flow arrangement, with the combustion section comprising:
• a combustor liner that at least partially defines a combustion chamber;
• and
• a fuel-air mixer fluidly coupled with the combustion chamber and comprising:
• a mixing tube defining a mixing channel including a mixing tube inlet, a mixing tube outlet fluidly coupled with the combustion chamber, and a mixing channel centerline, the mixing tube inlet including a fuel inlet to receive fuel and an air inlet to receive air, wherein the mixing channel includes a first section having a first inner dimension, a second section having a second inner dimension smaller than the first inner dimension and axially spaced downstream of the first section, and a third section having a third inner dimension smaller than the second inner dimension and axially spaced downstream of the second section;
• a first set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the mixing tube inlet;
• and
• a second set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the first set of air jets, the second set of air jets circumferentially offset from the first set of air jets;
• and
• a third set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the second set of air jets;
• wherein at least one of the first set of air jets, the second set of air jets, or the third set of air jets is tangentially arranged relative to the mixing channel centerline to introduce or increase a swirl of fuel and air in the mixing channel, and at least one other of the first set of air jets, the second set of air jets, or the third set of air jets are radially arranged relative to the mixing channel centerline to increase a spread of fuel in the mixing channel.

A gas turbine engine, comprising:

• a compressor section, a combustion section, and a turbine section in a serial flow arrangement, with the combustion section comprising:
• a combustor liner that at least partially defines a combustion chamber;
• and
• a fuel-air mixer configured to mix gaseous fuel including hydrogen fuel and being fluidly coupled with the combustion chamber, the fuel-air mixer comprising:
• a mixing tube defining a mixing channel including a mixing tube inlet, a mixing tube outlet fluidly coupled with the combustion chamber, and a mixing channel centerline, the mixing tube inlet including a fuel inlet to receive fuel and an air inlet to receive air;
• a first set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the mixing tube inlet;
• and
• a second set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the first set of air jets, the second set of air jets circumferentially offset from the first set of air jets;
• and
• a third set of air jets fluidly coupled with the mixing channel and axially spaced downstream of the second set of air jets;
• wherein at least one of the first set of air jets, the second set of air jets, or the third set of air jets is tangentially arranged relative to the mixing channel centerline to introduce or increase a swirl of fuel and air in the mixing channel, and at least one other of the first set of air jets, the second set of air jets, or the third set of air jets are radially arranged relative to the mixing channel centerline to increase a spread of fuel in the mixing channel, and
• wherein the air inlet is fluidly coupled with an air supply configured to provide the air with a speed of at least 100 ft/s and less than or equal to 200 ft/s.

A method of operating a gas turbine engine having a compressor section, a combustion section, and a turbine section in a serial flow arrangement, the method comprising:

• supplying compressed air from the compressor section to a mixing tube of the combustion section;
• supplying a flow of gaseous fuel into the compressed air in the mixing tube;
• laterally spreading the flow of gaseous fuel in a first lateral direction;
• laterally spreading the flow of gaseous fuel in a second lateral direction, which is different from the first lateral direction;
• imparting a swirl to the flow of gaseous fuel;
• supplying the swirled and laterally spread flow of gaseous fuel to a combustion chamber of the combustion section;
• and
• constricting the flow of gaseous fuel after laterally spreading the flow of gaseous fuel in the first lateral direction and before laterally spreading the flow of gaseous fuel in the second lateral direction.