Fuel nozzle and swirler
An engine can utilize a combustor to combust fuel to drive the engine. A fuel nozzle assembly can supply fuel to the combustor for combustion or ignition of the fuel. The fuel nozzle assembly can include a swirler and a fuel nozzle to supply a mixture of fuel and air for combustion. Increasing efficiency and emission needs require the use of alternative fuels, which combust at higher temperatures and faster burn speeds than traditional fuels, requiring improved fuel introduction without the occurrence of flame holding or flashback.
1 . A turbine engine comprising:
a compressor section, a combustor section, and a turbine section in serial flow arrangement, wherein the combustor section including a fuel nozzle assembly comprising:
a fuel nozzle defining a central longitudinal axis, and including a central gaseous fuel passage extending along the central longitudinal axis, the fuel nozzle terminating at a nozzle tip, with a nozzle cap located in the central gaseous fuel passage upstream of the nozzle tip and having multiple orifices through which a flow of gaseous fuel passes; and
a swirler, having a first swirler passage and a second swirler passage, provided about the fuel nozzle, the swirler comprising:
a forward wall terminating along the fuel nozzle at a location upstream of the nozzle tip,
an aft wall spaced from the forward wall,
a center wall provided between the forward wall and the aft wall and defining the first swirler passage between the center wall and the forward wall, and further defining the second swirler passage between the center wall and the aft wall,
a first set of vanes extending between the forward wall and the center wall,
a second set of vanes extending between the center wall and the aft wall, and
a splitter extending from the center wall and further defining the first swirler passage between the splitter and the forward wall and the second swirler passage between the splitter and the aft wall,
wherein the first set of vanes are arranged to impart a first tangential swirl to a first air flow passing through the first swirler passage, the first air flow having a first axial velocity with respect to the central longitudinal axis along an exterior of the fuel nozzle circumscribing the flow of gaseous fuel emitted from the nozzle tip,
wherein the second set of vanes are arranged to impart a second tangential swirl to a second air flow passing through the second swirler passage, the second air flow circumscribing the first air flow and having a second axial velocity with respect to the central longitudinal axis,
wherein the first tangential swirl is less than the second tangential swirl such that the second axial velocity is slower than the first axial velocity,
wherein the first tangential swirl has a first swirl number of greater than 0 and less than or equal to 0.6, while the second tangential swirl has a second swirl number of greater than 0 and less than or equal to 1.4,
wherein the fuel nozzle is configured to receive hydrogen fuel, and
wherein the splitter terminates at a splitter end that is spaced a length from the nozzle tip axially with respect to the center longitudinal axis, the splitter end is located a height from the aft wall radially with respect to the center longitudinal axis, and the length is greater than or equal to −10 times the height and less than or equal to 10 times the height.
2 . The turbine engine of claim 1 , wherein the splitter terminates aft of the nozzle tip.
3 . The turbine engine of claim 1 , wherein the forward wall further includes a foot abutting the fuel nozzle.
4 . The turbine engine of claim 3 , wherein the nozzle tip is positioned aft of the foot.
5 . The turbine engine of claim 3 , wherein the foot defines a step between the swirler and the fuel nozzle, the step being configured to receive a purge airflow directed radially between the foot and the fuel nozzle.
6 . The turbine engine of claim 1 , wherein the nozzle tip defines a diverging cross section.
7 . The turbine engine of claim 1 , wherein the splitter defines a converging section and the converging section includes the splitter end.
8 . The turbine engine of claim 7 , wherein the nozzle tip projects axially downstream beyond the forward wall of the swirler such that a terminal end of the nozzle tip is positioned upstream of the splitter end and exposed to the first air flow along the exterior of the fuel nozzle, the nozzle tip being configured to promote high-velocity impingement of the first air flow on the flow of gaseous fuel emitted from the nozzle tip to reduce flame holding and flashback.
9 . The turbine engine of claim 1 , wherein the multiple orifices impart a third tangential swirl to the flow of gaseous fuel.
10 . The turbine engine of claim 9 , wherein a first direction of the first tangential swirl and a second direction of the second tangential swirl are the same.
11 . The turbine engine of claim 1 , wherein the combustion section has a combustion chamber, and the fuel nozzle assembly further comprises a flare cone located downstream of the forward wall, the flare cone extending aft of the swirler and defining a fuel outlet opening into the combustion chamber, the flare cone defining a region that diverges radially outward from the central longitudinal axis in a downstream axial direction.
12 . A fuel nozzle assembly comprising:
a fuel nozzle, defining a central longitudinal axis, includes a central gaseous fuel passage extending along the central longitudinal axis and terminating at a nozzle tip, with a nozzle cap located in the central gaseous fuel passage upstream of the nozzle tip and having multiple orifices through which a flow of gaseous fuel passes; and
an annular swirler circumscribing the fuel nozzle, the annular swirler defining a first swirler passage and a second swirler passage, the annular swirler comprising:
a forward wall,
an aft wall spaced from the forward wall,
a center wall provided between the forward wall and the aft wall and defining the first swirler passage between the center wall and the forward wall, and further defining the second swirler passage between the center wall and the aft wall, and
a first set of vanes extending between the forward wall and the center wall,
a second set of vanes extending between the center wall and the aft wall, and
a splitter extending from the center wall and further defining the first swirler passage between the splitter and the forward wall and the second swirler passage between the splitter and the aft wall,
wherein the first set of vanes are configured to impart a first tangential swirl to a first air flow passing through the first swirler passage, the first air flow having a first axial velocity with respect to the central longitudinal axis along an exterior of the fuel nozzle circumscribing the flow of gaseous fuel emitted from the nozzle tip;
wherein the second set of vanes are configured to impart a second tangential swirl to a second air flow passing through the second swirler passage, the second air flow circumscribing the first air flow and having a second axial velocity with respect to the central longitudinal axis;
wherein the first tangential swirl is less than the second tangential swirl such that the second axial velocity is slower than the first axial velocity;
wherein the first tangential swirl has a first swirl number of greater than 0 and less than or equal to 0.6, while the second tangential swirl has a second swirl number of greater than 0 and less than or equal to 1.4,
wherein the fuel nozzle is configured to receive hydrogen fuel, and
wherein the splitter terminates at a splitter end that is spaced a length from the nozzle tip axially with respect to the center longitudinal axis, the splitter end is located a height from the aft wall radially with respect to the center longitudinal axis, and the length is greater than or equal to −10 times the height and less than or equal to 10 times the height.
13 . The fuel nozzle assembly of claim 12 , wherein the forward wall terminates at a foot, and wherein the foot terminates forward of the nozzle tip.
14 . The fuel nozzle assembly of claim 12 , wherein the splitter is arranged parallel to at least a portion of the aft wall.
15 . The fuel nozzle assembly of claim 12 , wherein the multiple orifices of the nozzle cap are configured to impart a third tangential swirl to the flow of gaseous fuel passing through the nozzle cap.
16 . The fuel nozzle assembly of claim 12 , wherein the nozzle tip defines a diverging cross section.
17 . The fuel nozzle assembly of claim 12 , wherein the splitter defines a converging section and the converging section includes the splitter end.
18 . The fuel nozzle assembly of claim 12 , further comprising a flare cone located downstream of the forward wall, the flare cone extending aft of the annular swirler and defining a fuel outlet opening into a combustion chamber, the flare cone defining a region that diverges radially outward from the central longitudinal axis in a downstream axial direction.
19 . A turbine engine comprising:
a compressor section, a combustor section, and a turbine section in serial flow arrangement, wherein the combustor section including a fuel nozzle assembly comprising:
a fuel nozzle defining a central longitudinal axis, and including a central gaseous fuel passage extending along the central longitudinal axis, the fuel nozzle terminating at a nozzle tip, with a nozzle cap located in the central gaseous fuel passage upstream of the nozzle tip and having multiple orifices through which a flow of gaseous fuel passes; and
a swirler, having a first swirler passage and a second swirler passage, provided about the fuel nozzle, the swirler comprising:
a forward wall terminating along the fuel nozzle at a location upstream of the nozzle tip,
an aft wall spaced from the forward wall,
a center wall provided between the forward wall and the aft wall and defining the first swirler passage between the center wall and the forward wall, and further defining the second swirler passage between the center wall and the aft wall, with a first air flow and a second air flow from the compressor section respectively supplied to the first swirler passage and the second swirler passage,
a first set of vanes extending between the forward wall and the center wall,
a second set of vanes extending between the center wall and the aft wall, and
a splitter extending from the center wall and further defining the first swirler passage between the splitter and the forward wall and the second swirler passage between the splitter and the aft wall,
wherein the first set of vanes are arranged to impart a first tangential swirl to the first air flow passing through the first swirler passage, the first air flow having a first axial velocity with respect to the central longitudinal axis along an exterior of the fuel nozzle circumscribing the flow of gaseous fuel emitted from the nozzle tip,
wherein the second set of vanes are arranged to impart a second tangential swirl to the second air flow passing through the second swirler passage, the second air flow circumscribing the first air flow and having a second axial velocity with respect to the central longitudinal axis,
wherein the first tangential swirl is less than the second tangential swirl such that the second axial velocity is slower than the first axial velocity,
wherein the first tangential swirl has a first swirl number of greater than 0 and less than or equal to 0.6, while the second tangential swirl has a second swirl number of greater than 0 and less than or equal to 1.4,
wherein the fuel nozzle is configured to receive hydrogen fuel, and
wherein the splitter terminates at a splitter end that is spaced a length from the nozzle tip axially with respect to the center longitudinal axis, the splitter end is located a height from the aft wall radially with respect to the center longitudinal axis, and the length is greater than or equal to −10 times the height and less than or equal to 10 times the height.
20 . The turbine engine of claim 19 , wherein the splitter end is located aft of the nozzle tip.