Abstract: Fuel nozzle assemblies are provided. For example, a fuel nozzle assembly for a combustor system comprises a fuel nozzle having a pilot swirler and an outlet defined in an outlet end, as well as a main mixer attached to the outlet end and extending about the outlet. A total combustor airflow through the combustor system comprises a pilot swirler airflow that is greater than about 14% and a main mixer airflow that is less than about 50% of the total combustor airflow. In further embodiments, the fuel nozzle also comprises main and pilot fuel injectors that each are configured to receive a portion of a fuel flow to the fuel nozzle. The fuel nozzle provides less than about 80% of the fuel flow to the main fuel injector at a high power operating condition of a gas turbine engine in which the fuel nozzle assembly is installed.

Abstract: Combustor systems are provided. For example, a combustor system comprises a combustor having forward and aft ends and including annular inner and outer liners that each extend generally along an axial direction and define a combustion chamber therebetween. The combustor system also comprises a fuel nozzle having an outlet defined in an outlet end of the fuel nozzle and including a pilot swirler. The outlet is positioned at the forward end of the combustor to direct a fuel-air mixture into the combustion chamber. The combustor system further comprises a main mixer attached to the outlet end of the fuel nozzle and extending about the outlet. A total combustor airflow through the combustor comprises a pilot swirler airflow that is greater than about 14% of the total combustor airflow and a main mixer airflow that is less than about 50% of the total combustor airflow.

Abstract: A premixer for a gas turbine combustor includes a centerbody, a swirler assembly, and a mixing duct. The swirler assembly includes an inner swirler with vanes that rotate air in a first direction and an outer swirler with vanes that rotate air in an opposite direction. The inner swirler vanes and the outer swirler vanes are separated by an annular splitter. The outer swirler vanes define an outlet plane, and the inner swirler vanes each have a trailing edge that is disposed at an acute angle relative to the outlet plane. In one aspect, the inner swirler is axially offset from the outer swirler. The mixing duct may also define fuel passages that deliver fuel to fuel outlets on the downstream end of the mixing duct. The premixer is designed for operation on gaseous fuel or liquid fuel.

Abstract: The present disclosure is directed to a combustor system including a fuel nozzle comprising a main fuel injector defining an angled main injection port. Each angled main injection port defines an inlet end and an outlet end. The outlet end is oriented downstream relative to the inlet end at an angle relative to a centerline axis of the fuel nozzle. The angled main injection port permits egress of fuel from a main fuel circuit to the combustion chamber. The fuel nozzle further defines a radial main injection port. The outlet end is oriented along an axial direction approximately equal relative to the inlet end and radially outward thereof relative to the centerline axis. The radial main injection port is extended perpendicular relative to the centerline axis.

Abstract: A flow conditioning system for a duct. The flow conditioning system includes a preconditioner that modifies upstream fluid flow that is maldistributed, providing predictable downstream flow to fluid flowing within the duct. The directional flow conditioner also includes a stationary flow geometry structure downstream of the preconditioner. The stationary flow geometry structure further conditions the upstream fluid flow from the preconditioner to provide a downstream flow with a substantially uniform flow profile. The flow conditioning system transforms upstream fluids having a maldistributed flow profile such as may be caused by a component, structure or obstruction within the duct to a substantially uniform flow profile downstream of the flow conditioning system within the available axial duct length so that the fluid may interact efficiently with equipment such as heat exchangers positioned within the duct downstream of the flow conditioning system.

Abstract: A premixer for a gas turbine combustor includes a centerbody, a swirler assembly, and a mixing duct. The swirler assembly includes an inner swirler with vanes that rotate air in a first direction and an outer swirler with vanes that rotate air in an opposite direction. The inner swirler vanes and the outer swirler vanes are separated by an annular splitter. The outer swirler vanes define an outlet plane, and the inner swirler vanes each have a trailing edge that is disposed at an acute angle relative to the outlet plane. In one aspect, the inner swirler is axially offset from the outer swirler. The mixing duct may also define fuel passages that deliver fuel to fuel outlets on the downstream end of the mixing duct. The premixer is designed for operation on gaseous fuel or liquid fuel.

Abstract: A flow conditioning system for a duct. The flow conditioning system includes a preconditioner that modifies upstream fluid flow that is maldistributed, providing predictable downstream flow to fluid flowing within the duct. The directional flow conditioner also includes a stationary flow geometry structure downstream of the preconditioner. The stationary flow geometry structure further conditions the upstream fluid flow from the preconditioner to provide a downstream flow with a substantially uniform flow profile. The flow conditioning system transforms upstream fluids having a maldistributed flow profile such as may be caused by a component, structure or obstruction within the duct to a substantially uniform flow profile downstream of the flow conditioning system within the available axial duct length so that the fluid may interact efficiently with equipment such as heat exchangers positioned within the duct downstream of the flow conditioning system.

Abstract: Combustor systems are provided. For example, a combustor system comprises a combustor having forward and aft ends and including annular inner and outer liners that each extend generally along an axial direction and define a combustion chamber therebetween. The combustor system also comprises a fuel nozzle having an outlet defined in an outlet end of the fuel nozzle and including a pilot swirler. The outlet is positioned at the forward end of the combustor to direct a fuel-air mixture into the combustion chamber. The combustor system further comprises a main mixer attached to the outlet end of the fuel nozzle and extending about the outlet. A total combustor airflow through the combustor comprises a pilot swirler airflow that is greater than about 14% of the total combustor airflow and a main mixer airflow that is less than about 50% of the total combustor airflow.

Abstract: Fuel nozzle assemblies are provided. For example, a fuel nozzle assembly for a combustor system comprises a fuel nozzle having a pilot swirler and an outlet defined in an outlet end, as well as a main mixer attached to the outlet end and extending about the outlet. A total combustor airflow through the combustor system comprises a pilot swirler airflow that is greater than about 14% and a main mixer airflow that is less than about 50% of the total combustor airflow. In further embodiments, the fuel nozzle also comprises main and pilot fuel injectors that each are configured to receive a portion of a fuel flow to the fuel nozzle. The fuel nozzle provides less than about 80% of the fuel flow to the main fuel injector at a high power operating condition of a gas turbine engine in which the fuel nozzle assembly is installed.

Abstract: The present disclosure is directed to a combustor system including a fuel nozzle comprising a main fuel injector defining an angled main injection port. Each angled main injection port defines an inlet end and an outlet end. The outlet end is oriented downstream relative to the inlet end at an angle relative to a centerline axis of the fuel nozzle. The angled main injection port permits egress of fuel from a main fuel circuit to the combustion chamber. The fuel nozzle further defines a radial main injection port. The outlet end is oriented along an axial direction approximately equal relative to the inlet end and radially outward thereof relative to the centerline axis. The radial main injection port is extended perpendicular relative to the centerline axis.

Abstract: A system and method for flame stabilization is provided that forestalls incipient lean blow out by improving flame stabilization. A combustor profile is selected that maintains desired levels of power output while minimizing or eliminating overboard air bleed and minimizing emissions. The selected combustor profile maintains average shaft power in a range of from approximately 50% up to full power while eliminating overboard air bleed in maintaining such power settings. Embodiments allow for a combustor to operate with acceptable emissions at lower flame temperature. Because the combustor can operate at lower bulk flame temperatures during part power operation, the usage of inefficient overboard bleed can be reduced or even eliminated.

Abstract: A system and method for flame stabilization is provided that forestalls incipient lean blow out by improving flame stabilization. A combustor profile is selected that maintains desired levels of power output while minimizing or eliminating overboard air bleed and minimizing emissions. The selected combustor profile maintains average shaft power in a range of from approximately 50% up to full power while eliminating overboard air bleed in maintaining such power settings. Embodiments allow for a combustor to operate with acceptable emissions at lower flame temperature. Because the combustor can operate at lower bulk flame temperatures during part power operation, the usage of inefficient overboard bleed can be reduced or even eliminated.

Abstract: A mixer for use in a combustion chamber of a gas turbine engine. The mixer includes an annular housing having an upstream end, a downstream end, a mount for attaching the housing to an upstream end of the combustion chamber, and an interior surface defining a hollow interior. The mixer also has a first swirler mounted inside the annular housing including a plurality of vanes extending inward from the housing for swirling air traveling through the housing. In addition, the mixer includes an annular fuel injector having a plurality of fuel injection ports arranged in a generally circular pattern mounted inside the first swirler for releasing droplets of fuel into swirling air downstream from the fuel injector. Further, the mixer has a second swirler mounted inside the fuel injector including a plurality of vanes extending inward from the injector for swirling air traveling through the housing downstream from the fuel injector.

Abstract: A mixer for use in a combustion chamber of a gas turbine engine. The mixer includes an annular housing having an upstream end, a downstream end, a mount for attaching the housing to an upstream end of the combustion chamber, and an interior surface defining a hollow interior. The mixer also has a first swirler mounted inside the annular housing including a plurality of vanes extending inward from the housing for swirling air traveling through the housing. In addition, the mixer includes an annular fuel injector having a plurality of fuel injection ports arranged in a generally circular pattern mounted inside the first swirler for releasing droplets of fuel into swirling air downstream from the fuel injector. Further, the mixer has a second swirler mounted inside the fuel injector including a plurality of vanes extending inward from the injector for swirling air traveling through the housing downstream from the fuel injector.

Abstract: A mixer for use in a combustion chamber of a gas turbine engine. The mixer includes an annular housing having an upstream end, a downstream end, a mount for attaching the housing to an upstream end of the combustion chamber, and an interior surface defining a hollow interior. The mixer also has a first swirler mounted inside the annular housing including a plurality of vanes extending inward from the housing for swirling air traveling through the housing. In addition, the mixer includes an annular fuel injector having a plurality of fuel injection ports arranged in a generally circular pattern mounted inside the first swirler for releasing droplets of fuel into swirling air downstream from the fuel injector. Further, the mixer has a second swirler mounted inside the fuel injector including a plurality of vanes extending inward from the injector for swirling air traveling through the housing downstream from the fuel injector.

Abstract: A gas turbine engine includes a combustor system to reduce an amount of nitrogen oxide emissions formed by the gas turbine engine. The combustor system includes a combustor including a first annular dome. A centerbody is secured within the dome and includes at least one orifice for supplying fuel to the dome. An inner swirler is attached to the centerbody and an outer swirler is attached radially outward from the inner swirler such that a leading edge of the inner swirler and a leading edge of the centerbody are disposed upstream from a leading edge of the outer swirler.

Abstract: A mixer assembly for use in a combustion chamber of a gas turbine engine. The assembly includes a pilot mixer and a main mixer. The pilot mixer includes an annular pilot housing having a hollow interior, a pilot fuel nozzle mounted in the housing adapted for dispensing droplets of fuel to the hollow interior of the pilot housing, and a plurality of concentrically mounted axial swirlers positioned upstream from the pilot fuel nozzle. Each of the swirlers has a plurality of vanes for swirling air traveling through the respective swirler to mix air and the droplets of fuel dispensed by the pilot fuel nozzle. The main mixer includes a main housing surrounding the pilot housing defining an annular cavity, a plurality of fuel injection ports for introducing fuel into the cavity, and a swirler positioned upstream from the plurality of fuel injection ports having a plurality of vanes for swirling air traveling through the swirler to mix air and the droplets of fuel dispensed by the fuel injection ports.

Abstract: A mixer assembly for use in a combustion chamber of a gas turbine engine. The assembly includes a pilot mixer and a main mixer. The pilot mixer includes an annular pilot housing having a hollow interior, a pilot fuel nozzle mounted in the housing and adapted for dispensing droplets of fuel to the hollow interior of the pilot housing, and one or more axial swirlers positioned upstream from the pilot fuel nozzle. The main mixer includes a main housing surrounding the pilot housing and defining an annular cavity, an annular fuel injector having a plurality of fuel injection ports arranged in a circular pattern surrounding the pilot housing and mounted inside the annular cavity of the main mixer for releasing droplets of fuel into swirling air downstream from the fuel injector, and one or more axial swirlers positioned upstream from the plurality of fuel injection ports.