Patent Description:
An engine, such as a turbine engine, includes a turbine that is driven by combustion of a combustible fuel within a combustor of the engine. The engine utilizes a fuel nozzle to inject the combustible fuel into the combustor. A swirler provides for mixing the fuel with air in order to achieve efficient combustion.

<CIT> discloses a gas turbine engine swirler. Each of a plurality of primary swirl vanes extend radially inwardly to a vane lip. Each of a plurality of secondary swirl vanes extend radially inwardly for swirling air therefrom. The swirler body also includes a tubular Venturi that extends aft from between the primary swirler vanes and the secondary swirler vanes for radially separating air swirled therefrom. The primary swirl vanes are configured to swirl air along a passageway and through an outlet that is oriented axially aft. <CIT> discloses a fuel nozzle for a gas turbine engine having a chevron splitter provided between first and second radial swirlers.

Aspects of the disclosure herein are directed to a fuel nozzle and swirler architecture located within an engine component, and more specifically to a fuel nozzle structure configured for use with heightened combustion engine temperatures, such as those utilizing a hydrogen fuel of hydrogen fuel mixes. Higher temperature fuels can eliminate carbon emissions, but generate challenges relating to flame holding or flashback due to the higher flame speed and high-temperatures. Current combustors may be susceptible to flame holding or flashback on combustor components when using such high-temperature fuels due. For purposes of illustration, the present disclosure will be described with respect to a turbine engine for an aircraft with a combustor driving the turbine. It will be understood, however, that aspects of the disclosure herein are not so limited, and can have application in other residential or industrial applications.

During combustion, the engine generates high local temperatures. Efficiency and carbon emission needs can be met with fuels that burn hotter than traditional fuels, or that reduce carbon emissions can be met by the use of fuels with higher burn temperatures. Such fuels can include lighter than air fuels, such as hydrogen in the gaseous phase. Utilizing current engines with fuels with higher burn temperatures and burn speeds may result in flame holding or flashback on the combustor components.

Reference will now be made in detail to the fuel nozzle and swirler architecture, and in particular for use with a turbine engine, one or more examples of which are illustrated in the accompanying drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure.

The terms "forward" and "aft" refer to relative positions within a turbine engine or vehicle, and refer to the normal operational attitude of the turbine engine or vehicle. For example, with regard to a turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust.

As used herein, the term "upstream" refers to a direction that is opposite the fluid flow direction, and the term "downstream" refers to a direction that is in the same direction as the fluid flow. The term "fore" or "forward" means in front of something and "aft" or "rearward" means behind something. For example, when used in terms of fluid flow, fore/forward can mean upstream and aft/rearward can mean downstream.

The term "fluid" may be a gas or a liquid. The term "fluid communication" means that a fluid is capable of making the connection between the areas specified.

The term "flame holding" relates to the condition of continuous combustion of a fuel such that a flame is maintained along or near to a component, and usually a portion of the fuel nozzle assembly as described herein, and "flashback" relate to a retrogression of the combustion flame in the upstream direction.

Additionally, as used herein, the terms "radial" or "radially" refer to a direction away from a common center. For example, in the overall context of a turbine engine, radial refers to a direction along a ray extending between a center longitudinal axis of the engine and an outer engine circumference.

All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, aft, etc.) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of aspects of the disclosure described herein. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate structural elements between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to one another. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary.

Furthermore, as used herein, the term "set" or a "set" of elements can be any number of elements, including only one.

Accordingly, a value modified by a term or terms, such as "about", "approximately", "generally", and "substantially", are not to be limited to the precise value specified. For example, the approximating language may refer to being within a <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> percent margin in either individual values, range(s) of values and/or endpoints defining range(s) of values.

The combustor introduces fuel from a fuel nozzle, which is mixed with air provided by a swirler, and then combusted within the combustor to drive the engine. Increases in efficiency and reduction in emissions have driven the need to use fuel that burns cleaner or at higher temperatures. There is a need to improve durability of the combustor under these operating parameters, such as improved flame control to prevent flame holding on the fuel nozzle and swirler components.

<FIG> is a schematic view of an engine as an exemplary turbine engine <NUM>. As a non-limiting example, the turbine engine <NUM> can be used within an aircraft. The turbine engine <NUM> can include, at least, a compressor section <NUM>, a combustion section <NUM>, and a turbine section <NUM>. A drive shaft <NUM> rotationally couples the compressor and turbine sections <NUM>, <NUM>, such that rotation of one affects the rotation of the other, and defines a rotational axis <NUM> for the turbine engine <NUM>.

The compressor section <NUM> can include a low-pressure (LP) compressor <NUM>, and a high-pressure (HP) compressor <NUM> serially fluidly coupled to one another. The turbine section <NUM> can include an LP turbine <NUM>, and an HP turbine <NUM> serially fluidly coupled to one another. The drive shaft <NUM> can operatively couple the LP compressor <NUM>, the HP compressor <NUM>, the LP turbine <NUM> and the HP turbine <NUM> together. Alternatively, the drive shaft <NUM> can include an LP drive shaft (not illustrated) and an HP drive shaft (not illustrated). The LP drive shaft can couple the LP compressor <NUM> to the LP turbine <NUM>, and the HP drive shaft can couple the HP compressor <NUM> to the HP turbine <NUM>. An LP spool can be defined as the combination of the LP compressor <NUM>, the LP turbine <NUM>, and the LP drive shaft such that the rotation of the LP turbine <NUM> can apply a driving force to the LP drive shaft, which in turn can rotate the LP compressor <NUM>. An HP spool can be defined as the combination of the HP compressor <NUM>, the HP turbine <NUM>, and the HP drive shaft such that the rotation of the HP turbine <NUM> can apply a driving force to the HP drive shaft which in turn can rotate the HP compressor <NUM>.

The compressor section <NUM> can include a plurality of axially spaced stages. Each stage includes a set of circumferentially-spaced rotating blades and a set of circumferentially-spaced stationary vanes. The compressor blades for a stage of the compressor section <NUM> can be mounted to a disk, which is mounted to the drive shaft <NUM>. Each set of blades for a given stage can have its own disk. The vanes of the compressor section <NUM> can be mounted to a casing which can extend circumferentially about the turbine engine <NUM>. It will be appreciated that the representation of the compressor section <NUM> is merely schematic and that there can be any number of stages. Further, it is contemplated, that there can be any other number of components within the compressor section <NUM>.

Similar to the compressor section <NUM>, the turbine section <NUM> can include a plurality of axially spaced stages, with each stage having a set of circumferentially-spaced, rotating blades and a set of circumferentially-spaced, stationary vanes. The turbine blades for a stage of the turbine section <NUM> can be mounted to a disk which is mounted to the drive shaft <NUM>. Each set of blades for a given stage can have its own disk. The vanes of the turbine section can be mounted to the casing in a circumferential manner. It is noted that there can be any number of blades, vanes and turbine stages as the illustrated turbine section is merely a schematic representation. Further, it is contemplated, that there can be any other number of components within the turbine section <NUM>.

The combustion section <NUM> can be provided serially between the compressor section <NUM> and the turbine section <NUM>. The combustion section <NUM> can be fluidly coupled to at least a portion of the compressor section <NUM> and the turbine section <NUM> such that the combustion section <NUM> at least partially fluidly couples the compressor section <NUM> to the turbine section <NUM>. As a non-limiting example, the combustion section <NUM> can be fluidly coupled to the HP compressor <NUM> at an upstream end of the combustion section <NUM> and to the HP turbine <NUM> at a downstream end of the combustion section <NUM>.

During operation of the turbine engine <NUM>, ambient or atmospheric air is drawn into the compressor section <NUM> via a fan (not illustrated) upstream of the compressor section <NUM>, where the air is compressed defining a pressurized air. The pressurized air can then flow into the combustion section <NUM> where the pressurized air is mixed with fuel and ignited, thereby generating combustion gases. Some work is extracted from these combustion gases by the HP turbine <NUM>, which drives the HP compressor <NUM>. The combustion gases are discharged into the LP turbine <NUM>, which extracts additional work to drive the LP compressor <NUM>, and the exhaust gas is ultimately discharged from the turbine engine <NUM> via an exhaust section (not illustrated) downstream of the turbine section <NUM>. The driving of the LP turbine <NUM> drives the LP spool to rotate the fan (not illustrated) and the LP compressor <NUM>. The pressurized airflow and the combustion gases can together define a working airflow that flows through the fan, compressor section <NUM>, combustion section <NUM>, and turbine section <NUM> of the turbine engine <NUM>.

<FIG> depicts a cross-section view of a combustor <NUM> suitable for use in the combustion section <NUM> of <FIG>. The combustor <NUM> can include an annular arrangement of fuel nozzle assemblies <NUM> for providing fuel to the combustor. It should be appreciated that the fuel nozzle assemblies <NUM> can be organized as in an annular arrangement including multiple fuel injectors. The combustor <NUM> can have a can, can-annular, or annular arrangement depending on the type of engine in which the combustor <NUM> is located. The combustor <NUM> can include an annular inner combustor liner <NUM> and an annular outer combustor liner <NUM>, a dome assembly <NUM> including a dome <NUM> and a deflector <NUM>, which collectively define a combustion chamber <NUM> about a longitudinal axis <NUM>. At least one fuel injector <NUM> is fluidly coupled to the combustion chamber <NUM> to supply fuel to the combustor <NUM>. The fuel injector <NUM> can be disposed within the dome assembly <NUM> upstream of a flare cone <NUM> to define a fuel outlet <NUM>. A swirler can be provided at the fuel nozzle assembly <NUM> to swirl incoming air in proximity to fuel exiting the fuel injector <NUM> and provide a homogeneous mixture of air and fuel entering the combustor <NUM>.

<FIG> illustrates a fuel nozzle assembly <NUM>, suitable for use in the combustor <NUM> as the fuel nozzle assembly <NUM>, including a fuel nozzle <NUM> defining a longitudinal axis <NUM>, and an annular swirler <NUM> circumscribing the fuel nozzle <NUM>. The fuel nozzle <NUM> can define a fuel passage <NUM>, with a nozzle cap <NUM> provided in the fuel passage <NUM> upstream of a nozzle tip <NUM>, relative to the fuel direction. The nozzle cap <NUM> can include a set of openings <NUM> which may or may not impart a swirl or tangential component to the fuel emitted from the nozzle tip <NUM>. As shown, the openings <NUM> are oriented tangentially, such that they appear to end within the cap <NUM>, while it should be appreciated the openings <NUM> extend fully through the cap <NUM> such that fuel can pass through the cap <NUM> via the openings <NUM>.

The swirler <NUM> includes a forward wall <NUM>, an aft wall <NUM>, and a central wall <NUM> with a set of vanes <NUM> provided therein, including a primary set of vanes 144a and a secondary set of vanes 144b, extending between the forward wall <NUM> and the central wall <NUM>, and between the aft wall <NUM> and the central wall <NUM>, respectively. The vanes <NUM> impart a tangential swirl to the airflow passing through the swirler <NUM> before exhausting. Furthermore, the forward wall <NUM> and the central wall <NUM> can define a forward passage <NUM> and the central wall <NUM> and the aft wall <NUM> can define an aft passage <NUM>. The primary set of vanes 144a can have a lesser swirl number compared to the secondary set of vanes 144b. Lower swirl from the primary set of vanes 144a achieves an increased axial velocity component along the fuel nozzle outer diameter to prevent flame holding. A higher swirl from the secondary set of vanes 144b achieves higher flow velocity on a diverging flare cone that prevents flame holding. In one non-limiting examples, the swirl from primary set of vanes 144a can be from <NUM> to <NUM> where swirl from the second set of vanes 144b can be from <NUM> to <NUM>, while wider ranges are contemplated.

A lip <NUM> extends in the downstream direction from the vanes <NUM> at the central wall <NUM> between the forward and aft passages <NUM>, <NUM>. The lip <NUM> extends in the radially inward direction, relative to the longitudinal extent of the fuel nozzle <NUM>, and then curves, turning in the aft direction. The lip <NUM> provides a high velocity component along the fuel nozzle <NUM>, which can reduce or eliminate flame holding and flashback along the fuel nozzle assembly. Furthermore, fuels with high burn speeds or temperatures, such as hydrogen, compared to common fuel can be utilized, while current systems would have durability issues under those operating conditions. Utilizing a hydrogen fuel can provide for reducing or eliminating emissions, such as carbon emissions, while maintaining or improving engine efficiency.

A purge opening <NUM>, which can be arranged as a set of circumferentially-arranged openings in one non-limiting example, can extend through the swirler <NUM> and the forward wall <NUM> and fluidly couple to the swirler <NUM> through the forward wall <NUM>. The purge opening <NUM> can be angled toward the fuel nozzle <NUM>, while it is further contemplated that the purge openings <NUM> can include a tangential component, such that the purge airflow provided by the purge openings <NUM> can be similar to a swirling airflow provided from the vanes <NUM> of the swirler <NUM>, which can reduce shear between the two airflows.

The aft curved lip <NUM> can be positioned between the forward passage <NUM> and the aft passage <NUM>, to provide for directing the airflow along the fuel nozzle <NUM> with a high velocity component. The curvature of the lip <NUM> provides for decreased wakes or smaller wake distances by utilizing the flow from the forward passage <NUM> to reduce or eliminate wake formed by the lip <NUM>.

A passage height H can be defined as the distance between the fuel nozzle <NUM> and the aft wall <NUM> of the swirler <NUM> downstream of the lip <NUM>, where the cross-sectional area for the passage height H can be constant extending in the aft direction along the aft wall <NUM>. Where the cross-sectional area defined by the passage height is non-constant, the passage height H can be defined as the smallest distance between the fuel nozzle <NUM> and the aft wall <NUM>, downstream of the lip <NUM>. In one example, the lip <NUM> can extend radially inward, toward and relative to the axial extent of the fuel nozzle <NUM>.

Furthermore, the curvature of the lip <NUM> can be defined. Specifically, the lip <NUM> can begin extending at a <NUM>-degree angle, relative to a radial direction R defined by the axial extent of the fuel nozzle <NUM>. The lip <NUM> can turn, curving from the axial extent toward the aft direction. Additionally, the lip <NUM> can be arranged at an incline relative to the fuel nozzle <NUM>, defining a lip axis <NUM>, which can define an angle <NUM> between <NUM>-degree and <NUM>-degrees relative to a radial axis R, while such a curvature would be <NUM>-degrees offset from an axis parallel to the longitudinal axis <NUM>. Additionally, other ranges are contemplated, such as any angle between <NUM>-degrees and <NUM>-degrees (zero degrees). In other examples, it is contemplated that the curvature can vary, such as varying in the circumferential direction, or in the radial direction along a circumferential axis, which can be aligned with or offset with the purge openings <NUM> in one non-limiting example. Such a variation can be +/- <NUM>-degrees, for example, while other or greater ranges are contemplated.

<FIG> illustrates a lip height that can be defined as a first height H1 and a swirler passage height can be defined as a second height H2. The first height H1 can be defined as the radial distance between a trailing edge <NUM> of the vanes <NUM> and an aft end <NUM> of the lip <NUM>, defined along a ray extending from the longitudinal axis <NUM> of <FIG>. The second height H2 can be defined as the radial distance between the fuel nozzle <NUM> and the aft wall <NUM>. In one example, the first height H1 can be defined between -<NUM>. 9H2 to <NUM>. That is, the first height H1 can be between <NUM> times the second height H2 with the lip <NUM> positioned radially exterior of the trailing edge <NUM> of the vanes <NUM>, or can be <NUM> times the second height H2 with the lip <NUM> positioned radially interior of the trailing edge <NUM> of the vanes <NUM>. In another example, the lip can extend radially inward from between <NUM>. 2H2 and <NUM>. 8H2, while additional or wider ranges are contemplated.

In yet another example, a swirler passage length L can be defined as the axial distance between the aft end <NUM> of the lip <NUM> and a nozzle tip <NUM> of the fuel nozzle <NUM>. The length L can be defined parallel to the fuel nozzle <NUM>, for example. The lip <NUM> can be sized or arranged such that the swirler passage length L can be between one (<NUM>) to six (<NUM>) times H2, while other ranges or sizes are contemplated.

In yet another example, the purge opening <NUM> can define a purge opening axis <NUM> as a centerline through the purge opening <NUM>. The purge opening <NUM> can be arranged such that the purge axis <NUM> is defined at an angle <NUM> relative to the fuel nozzle <NUM>, or the longitudinal axis <NUM> defined by the fuel nozzle <NUM> in <FIG>. The angle <NUM> can be between negative-ten (-<NUM>) degrees and sixty (<NUM>) degrees, where a negative angle represents the purge opening <NUM> oriented away from the fuel nozzle <NUM>, and a positive angle represents the purge opening <NUM> oriented toward the fuel nozzle <NUM>. Orienting the purge opening <NUM> toward the fuel nozzle <NUM> can impinge a purge flow along the fuel nozzle <NUM>, which can provide a higher velocity component along the outer diameter of the fuel nozzle <NUM>, which can reduce flashback or flame holding at the fuel nozzle <NUM>. The axial position of the fuel nozzle <NUM> can be such that the purge opening <NUM> impinges upon the fuel nozzle <NUM>, or such that the purge opening <NUM> impinges upon the fuel nozzle tip <NUM>.

Turning to <FIG>, an alternative fuel nozzle assembly <NUM> includes a fuel nozzle <NUM> and a swirler <NUM>. The swirler <NUM> includes a forward wall <NUM> and an aft wall <NUM>, with a set of vanes <NUM> extending between the forward wall <NUM> and the aft wall <NUM>. A swirler lip <NUM> extends from the trailing edge <NUM> of the set of vanes <NUM>. A purge opening <NUM> can extend axially, and can be arranged parallel to the fuel nozzle <NUM>, for example. The purge opening <NUM> can be arranged forward of the swirler lip <NUM>, such that there is no line-of-sight of the purge opening <NUM> when viewed axially into the fuel nozzle assembly <NUM> opposite of the flow direction. Said another way, the purge opening <NUM> or an outlet thereof, can be axially aligned and axially overlap with the swirler lip <NUM>. Eliminating the direct line-of-sight for the purge opening <NUM> can reduce or eliminate flashback at the fuel nozzle assembly <NUM>, or risk thereof to the purge openings <NUM>.

<FIG> shows another alternative fuel nozzle assembly <NUM> including a fuel nozzle <NUM> and a swirler <NUM>. The swirler <NUM> includes a forward wall <NUM> and an aft wall <NUM>, with a center wall <NUM> therebetween defining a primary swirler passage <NUM> and a secondary swirler passage <NUM>. A set of primary vanes <NUM> is provided in the primary swirler passage <NUM>, and a set of secondary vanes <NUM> is provided in the secondary swirler passage <NUM>. An annular lip <NUM> extends from the center wall <NUM> at the sets of vanes <NUM>, <NUM>, curving or angled from a radial direction to an axial direction.

A set of purge openings <NUM> are shaped into the swirler <NUM> and partially defined by the outer diameter of the fuel nozzle <NUM>. Referring briefly to <FIG>, it should be appreciated that the purge openings <NUM> can be formed as sets of discrete openings, which can include grooves or slots formed into the inner diameter wall of the swirler <NUM>, extending parallel to the fuel nozzle <NUM>. The cross-sectional shape for the purge openings <NUM>, best seen in <FIG> taken across section VII-VII of <FIG>, can be semicircular, while alternative shapes are contemplated, such as circular, elliptical, semielliptical, triangular, squared, rounded, or combinations thereof in non-limiting examples. Additionally, an annular opening extending fully around the fuel nozzle <NUM> is contemplated. The annular shape of the fuel nozzle <NUM> can be appreciated as shown.

Returning to <FIG>, in operation, a flow of air is provided through the swirler <NUM> to impart a swirl or tangential component to the flow of air in the primary and secondary swirler passages <NUM>, <NUM>. The purge openings <NUM> provide a high velocity along the outer diameter of the fuel nozzle <NUM>, which can reduce or eliminate flame holding or flashback on the fuel nozzle <NUM>. A higher tangential component in the secondary swirler passage <NUM> can reduce or eliminate flame holding on the flare cone <NUM>. The purge openings <NUM> can be arranged tangentially, complementary or equivalent to the tangential swirl imparted by the primary swirler passage <NUM>.

Referring to <FIG>, another alternative fuel nozzle assembly <NUM> includes a fuel nozzle <NUM> and a swirler <NUM>. The swirler <NUM> includes a forward wall <NUM>, an aft wall <NUM>, and a center wall <NUM> therebetween defining a primary swirler passage <NUM> and a secondary swirler passage <NUM>. A first set of vanes <NUM> is provided in the primary swirler passage <NUM> and a second set of vanes <NUM> is provided in the secondary swirler passage <NUM>.

A set of purge openings <NUM> are circumferentially arranged about the swirler <NUM> forward of the forward wall <NUM>. The purge openings <NUM> can couple to an annular groove <NUM> formed into the forward wall <NUM>, which can be common to all purge openings <NUM> in the set of purge openings <NUM>. The groove <NUM> can include a rounded profile, while any profile is contemplated, such as rounded, curved, linear, curvilinear, geometric, circular, elliptical, squared, or combinations thereof in non-limiting examples. Furthermore, the groove <NUM> can be shaped to define a converging cross-sectional area in the flow direction to provide an increased velocity component for the flow emitted from the groove <NUM>, which can reduce flame holding or flashback at the fuel nozzle <NUM>. Alternatively, it is contemplated that the groove <NUM> can include a constant cross-section or a diverging cross-section. Furthermore, the purge openings <NUM> can be inclined, or angled toward the fuel nozzle <NUM>, while other suitable arrangements are contemplated, such as a radially-angular component, an axially-angular component, a circumferentially-angular component, or combination thereof. Further still, the cross-sectional area can vary in the circumferential direction, which may or may not relate to the arrangement of the purge openings <NUM>. The groove <NUM> can further provide for even spread of a purge flow before supply to the swirler <NUM>, which can reduce shear turbulence generated from discrete purge opening outlets.

<FIG> shows another alternative fuel nozzle assembly <NUM>, which can be similar to that of <FIG>, except that an annular groove <NUM> can be fed from multiple purge openings <NUM>, which can be in a stacked arrangement <NUM>, stacked in a radial direction relative to a fuel nozzle <NUM> of the fuel nozzle assembly <NUM>. It should be appreciated that utilizing different arrangements of purge openings <NUM> can provide a uniform supply of air to the annular groove <NUM>, which can be utilized to provide circumferentially-uniform flow profiles to a swirler <NUM>, while utilizing discrete purge openings <NUM>. Discrete or complex geometries can provide for tailoring an air profile emitted from the purge openings to the swirler <NUM>. Such geometries can be utilized to improve velocity along the fuel nozzle <NUM> to reduce flame holding on the nozzle tip, or improved swirl which can reduce flame holding on a flare cone or combustor liner.

<FIG> depicts yet another alternative fuel nozzle assembly <NUM> including a fuel nozzle <NUM> and a swirler <NUM>. The swirler <NUM> includes a forward wall <NUM> and an aft wall <NUM>, with a central wall <NUM> therebetween defining a first passage <NUM> and a second passage <NUM>. A first set of vanes <NUM> is provided in the first passage <NUM> and a second set of vanes <NUM> is provided in the second passage <NUM>. A lip <NUM> extends radially inward from the central wall <NUM> at a trailing edge <NUM> of the vanes <NUM>, <NUM>. The lip <NUM> includes a t-shaped profile, such that a first portion <NUM> of the lip <NUM> extends in the radial direction, which splits into a forward portion <NUM> and an aft portion <NUM> extending forward and aft from the first portion <NUM>, respectively.

The t-shape of the lip <NUM> defines a constant cross-sectional area defined in the radial direction from the forward and aft portions <NUM>, <NUM> to the fuel nozzle <NUM>. The constant cross-sectional area provides a higher axial velocity component along the outer diameter of the fuel nozzle <NUM>, which can provide for reducing or eliminating flame holding or flashback at the fuel nozzle <NUM>.

It should be appreciated that fuels with higher burn temperature and higher burn speeds, or lighter weights relative to air or other fuels, can provide for reducing or eliminating emissions, or improving efficiency without increasing emissions. In one example, hydrogen fuels or hydrogen-based fuels can be utilized, which can eliminate carbon emissions without negative impact to efficiency. Such fuels, including hydrogen, require greater flame control, in order to prevent flame holding or flashback on the combustor hardware. The aspects described herein can increase combustor durability, while current combustors fail to provide durability to utilize such fuels.

It should be appreciated that the examples used herein are not limited specifically as shown, and a person having skill in the art should appreciate that aspects from one or more of the examples can be intermixed with one or more aspect from other examples to define examples that can differ from the examples as shown.

Claim 1:
A turbine engine (<NUM>) comprising:
a compressor section (<NUM>), combustor section (<NUM>), and turbine section (<NUM>) in serial flow arrangement, with the combustor section (<NUM>) including a fuel nozzle assembly (<NUM>) comprising:
a fuel nozzle (<NUM>) terminating at a nozzle tip (<NUM>), the fuel nozzle (<NUM>) defining a longitudinal axis (<NUM>), and including a fuel passage (<NUM>), wherein the fuel passage (<NUM>) extends along the longitudinal axis (<NUM>);
a swirler (<NUM>), the swirler (<NUM>) being an annular swirler circumscribing the fuel nozzle (<NUM>) and defining a swirler passage (<NUM>), and comprising a forward wall (<NUM>), an aft wall (<NUM>), and a center wall (<NUM>) provided between the forward wall (<NUM>) and the aft wall (<NUM>);
a set of vanes (<NUM>) provided within the swirler (<NUM>), wherein the set of vanes (<NUM>) includes a first set of vanes (144a) extending between the forward wall (<NUM>) and the center wall (<NUM>), and a second set of vanes (144b) extending between the center wall (<NUM>) and the aft wall (<NUM>); and
a lip (<NUM>) extending downstream from the set of vanes (<NUM>) relative to a flow of air through the swirler (<NUM>);
wherein the lip (<NUM>) extends from the center wall (<NUM>);
wherein the nozzle tip (<NUM>) is positioned aft of the aft end (<NUM>) of the lip (<NUM>) relative to the longitudinal axis and the swirler passage (<NUM>) extends between the aft end (<NUM>) of the lip (<NUM>) and the nozzle tip; and
wherein the aft end (<NUM>) of the lip (<NUM>) is positioned forward of the aft wall (<NUM>) relative to the longitudinal axis (<NUM>);
characterized in that the fuel passage (<NUM>) terminates at the nozzle tip (<NUM>).