Combustor for a turbine engine

1. A combustor for a turbine engine, the combustor comprising:

a fuel injector having a mixer assembly with a pilot mixer and a main mixer, the fuel injector injecting fuel through the pilot mixer to generate a pilot fuel stream and through the main mixer to generate a main fuel stream;

a fluid injection system in fluid communication with the combustor, the fluid injection system injecting a fluid into the combustor; and

a controller that is communicatively coupled to the fuel injector and the fluid injection system, wherein the controller:

controls the fuel injector to inject the pilot fuel stream through the pilot mixer and the main fuel stream through the main mixer during a high power operation of the turbine engine;

controls the fluid injection system to inject the fluid into the combustor during the high power operation; and

controls the fluid injection system to shut off the fluid into the combustor during an entirety of a low power operation of the turbine engine and during an entirety of a mid-level power operation of the turbine engine,

wherein the low power operation is less than 30% of a maximum rated thrust of the turbine engine, the mid-level power operation is 30% to 85% of the maximum rated thrust of the turbine engine, and the high power operation is greater than 85% of the maximum rated thrust of the turbine engine.

2. The combustor of claim 1 , wherein the controller controls the fuel injector to shut off the main fuel stream through the main mixer during the low power operation of the turbine engine.

3. The combustor of claim 1 , wherein the fluid injection system comprises a fluid supply and a pump, and the controller controls the pump to pump the fluid from the fluid supply into the combustor.

4. The combustor of claim 1 , wherein the high power operation is during a takeoff condition or a climb condition of the turbine engine, the mid-level power operation is during a cruise condition of the turbine engine, and the low power operation is during an engine start condition, an idle condition, a taxiing condition, or a descent condition of the turbine engine.

5. The combustor of claim 1 , further comprising an igniter that ignites a rich fuel-air mixture from the pilot mixer to generate a pilot flame in the combustor, and ignites a lean fuel-air mixture from the main mixer to generate a main flame in the combustor.

6. The combustor of claim 1 , further comprising one or more first sensors that sense operating conditions of compressed air entering the mixer assembly, and the controller controls the fuel injector to inject the pilot fuel stream through the pilot mixer and the main fuel stream through the main mixer based on the operating conditions of the compressed air.

7. The combustor of claim 6 , further comprising one or more second sensors that sense operating conditions of combustion gases exiting the combustor, wherein the controller controls a fuel split between the pilot mixer and the main mixer based on the operating conditions of the combustion gases.

8. The combustor of claim 6 , further comprising one or more second sensors that sense operating conditions of combustion gases exiting the combustor, wherein the controller controls a compressed air split between the pilot mixer and the main mixer based on the operating conditions of the combustion gases.

9. A turbine engine comprising:

a combustor comprising a fuel injector having a mixer assembly with a pilot mixer and a main mixer, the fuel injector injecting fuel through the pilot mixer to generate a pilot fuel stream and through the main mixer to generate a main fuel stream;

a fluid injection system in fluid communication with the combustor, the fluid injection system injecting a fluid into the combustor; and

a controller that is communicatively coupled to the fuel injector and the fluid injection system, wherein the controller:

controls the fuel injector to inject the pilot fuel stream through the pilot mixer and the main fuel stream through the main mixer during a high power operation of the turbine engine;

controls the fluid injection system to inject the fluid into the combustor during the high power operation; and

controls the fluid injection system to shut off the fluid into the combustor during an entirety of a low power operation of the turbine engine and during an entirety of a mid-level power operation of the turbine engine,

wherein the low power operation is less than 30% of a maximum rated thrust of the turbine engine, the mid-level power operation is 30% to 85% of the maximum rated thrust of the turbine engine, and the high power operation is greater than 85% of the maximum rated thrust of the turbine engine.

10. The turbine engine of claim 9 , wherein the controller controls the fuel injector to shut off the main fuel stream through the main mixer during the low power operation of the turbine engine.

11. The turbine engine of claim 9 , wherein the fluid injection system comprises a fluid supply and a pump, and the controller controls the pump to pump the fluid from the fluid supply into the combustor.

12. The turbine engine of claim 9 , further comprising an igniter that ignites a rich fuel-air mixture from the pilot mixer to generate a pilot flame in the combustor, and ignites a lean fuel-air mixture from the main mixer to generate a main flame in the combustor.

13. The turbine engine of claim 9 , further comprising one or more first sensors that sense operating conditions of compressed air entering the mixer assembly, and the controller controls the fuel injector to inject the pilot fuel stream through the pilot mixer and the main fuel stream through the main mixer based on the operating conditions of the compressed air.

14. The turbine engine of claim 13 , further comprising one or more second sensors that sense operating conditions of combustion gases exiting the combustor, wherein the controller controls a fuel split between the pilot mixer and the main mixer based on the operating conditions of the combustion gases.

15. The turbine engine of claim 13 , further comprising one or more second sensors that sense operating conditions of combustion gases exiting the combustor, wherein the controller controls a compressed air split between the pilot mixer and the main mixer based on the operating conditions of the combustion gases.

16. The turbine engine of claim 9 , wherein the high power operation is during a takeoff condition or a climb condition of the turbine engine, the mid-level power operation is during a cruise condition of the turbine engine, and the low power operation is during an engine start condition, an idle condition, a taxiing condition, or a descent condition of the turbine engine.