Patent Description:
An engine, such as a turbine engine that includes a turbine, 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> relates to a fuel nozzle. The fuel nozzle includes a center body configured to receive a first portion of air and to deliver the air to a combustion region. The fuel nozzle also includes a swirler configured to receive a second portion of air and to deliver the air to the combustion region. The swirler includes an outer shroud wall, an inner hub wall, and a swirl vane. The swirl vane includes a radial swirl profile at a downstream edge of the swirl vane. The radial swirl profile includes a region extending from the outer shroud wall to a first transition point and a second region extending from the transition point to the inner hub wall. At least one of the first and second regions is substantially straight and at least one of the first and second regions is arcuate.

<CIT> relates to a fuel nozzle and swirler assembly for an engine, comprising a fuel nozzle including a fuel passage defining a longitudinal axis and a swirler. The swirler comprises a forward wall, an aft wall spaced from the forward wall to define a swirler passage therebetween, and a set of vanes provided in the swirler passage. The set of vanes extends between the forward wall and the aft wall and is configured to impart a tangential component to a volume of fluid passing through the swirler.

<CIT> relates to a fuel nozzle and swirler assembly for an engine, comprising a fuel nozzle including a fuel passage defining a longitudinal axis and a swirler. The swirler comprises a forward wall, an aft wall spaced from the forward wall to define a swirler passage therebetween and a set of vanes provided in the swirler passage extending between the forward wall and the aft wall. The forward wall is arranged at an incline angle relative to a radius defined orthogonal to the longitudinal axis.

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 other mixes thereof. 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 may have general applicability within an engine, including but not limited to turbojet, turboprop, turboshaft, and turbofan engines, as well as in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications. The fuel nozzle and swirler assembly according to the invention is defined in claim <NUM> and claim <NUM>.

Reference will now be made in detail to the fuel nozzle assembly architecture, portions thereof, or alternative embodiments thereof, and in particular the fuel nozzle and swirler for providing fuel to the combustor located within an engine, examples of which are illustrated in the accompanying drawings as a turbine. 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 an engine or vehicle, and refer to the normal operational attitude of the engine or vehicle. For example, with regard to an 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 "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 and swirler assembly as described herein, and the term "flashback" relate to a retrogression of the combustion flame in the upstream direction.

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.

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 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 and 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 <NUM>. As a non-limiting example, the engine <NUM> can be used within an aircraft. The 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 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 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 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 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 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 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 air 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 engine <NUM>.

<FIG> shows a fuel nozzle assembly <NUM> including a swirler <NUM> and a fuel nozzle <NUM> terminating at a nozzle tip <NUM>, including a fuel passage <NUM> defining a longitudinal axis <NUM>, and provided at least partially interior of the swirler <NUM>. The swirler <NUM> includes a set of vanes <NUM> that impart a swirl as a helical or tangential component to an airflow passing along the vanes <NUM>. The swirling air is directed through an exhaust passage <NUM> with the air exhausting at an outlet <NUM>. The vanes <NUM> includes a leading edge (not shown) and a trailing edge <NUM>, and extend between a radially-inner wall <NUM> and a radially-outer wall <NUM> defining the exhaust passage <NUM> therebetween. The trailing edge <NUM> can be cut back at a cutback angle <NUM> relative to the longitudinal axis <NUM> defined through the fuel nozzle <NUM>. In another non-limiting example, the trailing edge cutback angle <NUM> can be relative to the engine centerline <NUM> of <FIG>. The cutback angle <NUM> can be between <NUM>-degrees and <NUM>-degrees, or can be between <NUM>-degrees and <NUM>-degrees in another non-limiting example, or any other non-zero angle, while other angles or ranges thereof are contemplated.

In operation, a flow of air can be provided by the swirler <NUM>, imparted with a tangential swirling component passing axially about the fuel nozzle <NUM>. The vanes <NUM> impart a swirl, or tangential or helical component, to the air, such that the air swirls as it is emitted from the swirler <NUM>. The cutback angle <NUM> for the trailing edge <NUM> creates a higher angular component to the airflow at an outer diameter of the exhaust passage <NUM>, defining a lower angular component nearer to an inner diameter of the exhaust passage <NUM>, relative to the outer diameter. Additionally, the cutback angle <NUM> creates a high axial velocity component nearer to the inner diameter of the exhaust passage <NUM>, while having a relatively lesser axial velocity component nearer to the outer diameter. The higher swirl component at the outer diameter prevents or reduces flame holding on the fuel nozzle assembly <NUM>, while the higher axial velocity component at the inner diameter prevents flame holding and flashback on the outer surface or end of the fuel nozzle <NUM>. In one non-limiting example, it is contemplated that the vanes <NUM> or the swirler <NUM> can be part of or integral with the fuel nozzle <NUM>, as a unitary component. The cutback angle <NUM> can start at any radial vane location, relative to the longitudinal axis <NUM>, and it is contemplated that the cutback angle <NUM> can increase extending toward the inner diameter of the swirler <NUM>, such that the trailing edge <NUM> is curved. In another example, the cutback angle <NUM> can start at any location between <NUM>%-<NUM>% of the passage height between the radially-inner and radially-outer walls <NUM>, <NUM>, where <NUM>% is aligned with the radially outer wall <NUM> in the radial direction, and <NUM>% is aligned with the radially-inner wall <NUM>.

Additionally, the nozzle tip <NUM> can be positioned aft of swirler <NUM>. Such an aft positioning can provide sufficient space for the wake of the airflow provided from the swirler <NUM> to mix, aft of the swirler <NUM> and the fuel nozzle <NUM>, which provides to reduce or eliminate flame holding and flashback at the nozzle tip <NUM>.

A foot <NUM> of the radially inner wall <NUM> directs the air to slide along the foot <NUM> and transitioning to along the outer diameter of the fuel nozzle <NUM> to significantly reduce wakes at aft edge of the radially inner wall <NUM>. The angle on the foot <NUM> can be defined from <NUM>-degress to <NUM>-degrees with respect to the longitudinal axis <NUM> or an axis parallel thereto, to control flow velocity on the outer diameter of the fuel nozzle <NUM>, as well as reduce wakes the aft edge of the radially inner wall <NUM>. The radially outer wall <NUM> includes a converging wall section <NUM> to direct the flow towards the fuel nozzle <NUM> to create high velocity on the fuel nozzle outer diameter to avoid flame holding. The angle for the converging wall section <NUM> can be between <NUM>-degree and <NUM>-degrees, or <NUM>-degrees and <NUM>-degrees, relative to the longitudinal axis <NUM>, while other ranges are contemplated such as any non-zero angle. Convergence of the swirler passage area defined by the foot <NUM> and the converging wall section <NUM> is followed by a constant area section <NUM> to create a well developed velocity profile at the outlet <NUM> of the exhaust passage <NUM> to keep the flame away from fuel nozzle assembly <NUM>. The length of the constant area section <NUM> can be from <NUM> to <NUM>, where H is the height of the exhaust passage <NUM> defined between radially-outer wall <NUM> and fuel nozzle <NUM> located aft of the foot <NUM> and the converging wall section <NUM>. The tip of the fuel nozzle <NUM> can be positioned anywhere in constant area section <NUM> or converging wall section <NUM> of the swirler assembly downstream of the swirler vanes <NUM>.

Turning to <FIG>, another exemplary fuel nozzle assembly <NUM> includes a swirler <NUM> and a fuel nozzle <NUM>. The swirler <NUM> includes a set of circumferentially arranged radial vanes <NUM> provided between a front wall <NUM> and a rear wall <NUM>. The swirler <NUM> turns airflow from a radial direction at the radial vanes <NUM> to an axial direction at an axial passage <NUM> that circumscribes the fuel nozzle <NUM>. A flare cone <NUM> extends from the swirler <NUM> downstream of the axial passage <NUM>. In one example, the flare cone <NUM> can extend at an angle <NUM> between -<NUM>-degrees (negative <NUM>-degrees) to <NUM>-degrees, relative to the longitudinal axis of the fuel nozzle <NUM>, where a negative angle defines a converging cross-sectional area, and a positive angle defines a diverging cross-sectional area, and zero-degrees represents a constant cross section for the flare cone <NUM>. In alternative examples, it is contemplated that the flare cone <NUM> can include a constant, diverging, or converging cross-sectional area, and need not be limited as shown. In another alternative example, it is contemplated that no flare is included.

The radial vanes <NUM> can be arranged to introduce a radial flow into the swirler <NUM> which exhausts at a trailing edge <NUM> at an opening <NUM>, sometimes referred to as a nozzle between adjacent radial vanes <NUM>, defining an outlet for the nozzle. The openings <NUM> can be oriented tangentially to impart a swirl to the flow of air provided from the swirler <NUM>. The tangential openings <NUM> create a high velocity component for the airflow along the axial direction along the outer diameter of the axial passage <NUM>, which prevents flame holding against the flare cone <NUM>. Additionally, the tangential openings <NUM> provide a high velocity component along the inner diameter of the axial passage <NUM>, which prevents flame holding or flashback at the fuel nozzle <NUM>.

Turning to <FIG>, a swirler <NUM> for a fuel nozzle assembly, such as the fuel nozzle assemblies as described herein, includes a housing <NUM> having a forward wall <NUM> and an aft wall <NUM>. A set of vanes <NUM> extend between the forward wall <NUM> and the art wall <NUM> for imparting a tangential swirl to an airflow provided to a fuel nozzle assembly.

Turning to <FIG>, taken along section V-V of <FIG>, near the forward wall <NUM>, showing vanes <NUM> that have a radial arrangement relative to the annular forward wall <NUM>. <FIG> shows a section view taken along section VI-VI of <FIG>, which illustrates the vanes <NUM> located between the forward wall <NUM> and the aft wall <NUM> (see <FIG>, aft wall <NUM> not shown in <FIG>), showing the vanes <NUM> turning from a radial direction toward a tangential direction, with a trailing edge <NUM> of each vane <NUM> turning tangentially. <FIG> shows a cross-sectional view taken along section VII-VII of <FIG>, which shows a section near to the aft wall <NUM> showing the trailing edge <NUM> of the vanes <NUM> turned further tangentially, while less tangentially extending toward a leading edge <NUM>, comparatively with the trailing edge <NUM>. The vanes <NUM>, as shown as radial in section V-V, are arranged along a radius extending from the center of the swirler, before turning to radial, as shown in <FIG>. The axial position where the vanes <NUM> begin to turn from radial to axial can vary between <NUM>% to <NUM>% of the total vane height, where the vane height is defined between the forward and aft walls <NUM>, <NUM> of the swirler <NUM>.

As the vanes <NUM> turn tangentially along the trailing edge <NUM>, an airflow directed along the vanes <NUM> provides for peak airflow velocity before interacting with the fuel flow provided by a fuel nozzle. The tangential curve for the trailing edge <NUM> can provide a high tangential velocity component along the outer diameter of an axial swirler passage downstream from the swirler <NUM>, which prevents flame holding on the fuel nozzle assembly or a downstream flare cone. The forward radial component of the vanes <NUM>, defined by the geometry as shown in section V-V in <FIG>, does not have a tangential component of velocity for the flow, and creates high axial velocity as the flow turns towards a fuel nozzle. This high axial velocity created by forward radial component of the vanes <NUM> results in high axial velocity at the aft end of the fuel nozzle, preventing flame holding on the tip of the fuel nozzle.

<FIG> shows the forward wall <NUM> and the aft wall <NUM> that are aligned parallel to one another, or orthogonal to a longitudinal axis for the fuel nozzle, or both. <FIG>, show non-limiting alternative examples, which can be utilized to vary the velocity profile for the airflow provided by a swirler. <FIG> shows a forward wall <NUM> that includes an incline which can be defined by an incline angle <NUM>, defined relative to an aft wall <NUM>, or a radius <NUM> extending from a longitudinal axis of the fuel nozzle and swirler assembly, or the forward wall <NUM> can be defined non-orthogonal to the longitudinal extent of a fuel nozzle utilized with the swirler including the forward wall <NUM>. Similarly, <FIG> shows an aft wall <NUM> that includes an incline defined by an incline angle <NUM>, relative to a radius <NUM> or a forward wall <NUM>. The forward or aft incline of <FIG> can define a converging cross-sectional area <NUM>, <NUM> for a swirler, which can provide for increasing velocity for the airflow passing through the swirler, controlling where the local velocity profile can increase or decrease based upon the angle or incline of the wall, which can improve the velocity profile for the airflow and reduce or prevent flame holding at the fuel nozzle assembly. As the passage between forward wall <NUM> and aft wall <NUM> is varied, a span of vanes provided in the swirler between the forward and aft walls <NUM>, <NUM> can reduce in the aft direction, which helps to achieve desired velocity profile as the air flow exits the vanes. The incline angle <NUM>, <NUM> can be between <NUM>-degrees and <NUM>-degrees, while other ranges are contemplated.

In another example, <FIG> shows a forward wall <NUM> and an aft wall <NUM> that are both inclined at an incline angle <NUM>, being offset from orthogonal, relative to the longitudinal extent of a fuel nozzle or an engine centerline, in non-limiting examples. The inclined forward and aft walls <NUM>, <NUM> of also provide a converging cross-sectional area <NUM> to provide an increased velocity for the airflow provided by a swirler. The incline angle <NUM> can be from <NUM>-degrees to <NUM>-degrees, for example.

<FIG> shows another example that includes a forward wall <NUM> and an aft wall <NUM> that both converge, defining a decreasing cross-sectional area <NUM>, transitioning to diverging portions of the forward wall <NUM> and aft wall <NUM>, defining a diverging cross-sectional area <NUM>. Instead of a planar surface it is possible that the forward and aft walls <NUM>, <NUM> can be curved. Radial height of the passage at which transitioning between converging to diverging area occurs can be between <NUM>% to <NUM>% of the total radial height of the swirler passage, for example.

It should be appreciated that additional combinations exist, where the forward wall or the aft wall include an incline or a decline, or a curvature for the wall, either concave or convex, that defines an increasing or decreasing cross-sectional area, or any combination thereof among both the forward wall and the aft wall individually, irrespective of the other wall or in complement with the other wall. It should be appreciated that the forward and aft walls for a swirler can be angled, individually or together, or in complement. Additionally, each wall can be angled, non-angled, or curved discretely to define converging or diverging portions for the swirler, which can define complex airflow profiles for a swirler.

<FIG> shows an enlarged, section view of a portion of an exemplary swirler <NUM> including two vanes <NUM> extending between a forward wall <NUM> and an aft wall <NUM>. Each vane <NUM> can include a constant cross-sectional area extending between the forward wall <NUM> and the aft wall <NUM>.

<FIG> illustrate alternative examples for the cross-sectional profile for a swirler with vanes defined between forward and aft walls. <FIG> illustrates a swirler <NUM> with vanes <NUM> that include an increasing cross-sectional flow area <NUM> extending in a direction from a forward wall <NUM> to an aft wall <NUM>, or a decreasing vane thickness extending from the forward wall <NUM> to the aft wall <NUM>. This geometry creates lower flow area at the forward wall <NUM> and relatively higher flow area at the aft wall <NUM> of the vane passage which results in high velocity on the outer diameter of an axial swirler passage, such as that described in <FIG>, and relatively lower velocity in the axial swirler passage on the fuel nozzle outer diameter. In other words, the geometry creates a peak velocity profile at a radial exterior of the axial swirler passage. A high velocity flow on the outer diameter of the swirler or flare cone prevents flame holding on the flare cone.

<FIG> illustrates a swirler <NUM> with vanes <NUM> that include a decreasing cross-sectional flow area <NUM> or an increasing vane thickness, extending from a forward wall <NUM> to an aft wall <NUM>. This geometry creates an peak radially-inner velocity profile at the axial swirler passage. A high velocity component on the outer diameter of the fuel nozzle reduces or eliminates flame holding on the fuel nozzle.

<FIG> includes a swirler <NUM> with vanes <NUM> that include a profile that includes a decreasing cross-sectional flow area <NUM> and then an increasing cross-sectional flow area <NUM> or an increasing vane thickness transitioning to a decreasing vane thickness, extending between a forward wall <NUM> and an aft wall <NUM>. This geometry creates a dual peak velocity profile with peak velocities on both the inner diameter and the outer diameter of swirler axial passage. This creates a high velocity flow near both flare cone and fuel nozzle wall preventing flame holding on both surfaces.

<FIG> includes a swirler <NUM> with vanes <NUM> that include an increasing cross-sectional flow area <NUM> which transitions to a decreasing cross-sectional flow area <NUM>, or an increasing vane thickness transitioning to a decreasing vane thickness, extending from a forward wall <NUM> to an aft wall <NUM>. This geometry creates center peak velocity profile at swirler axial passage that prevents flame holding or flashback in the center of the swirler axial passage. Transitioning of the vane thickness can occur anywhere from <NUM>% to <NUM>% of the length defined from forward wall <NUM> to aft wall <NUM> of the radial swirler passage. It is possible that the vane surface can be curved surfaces instead of a planar surface or combinations thereof are possible. A decreasing or converging cross-sectional area can be utilized to accelerate the flow, while the increasing or diverging cross-sectional area can be utilized to decelerate the flow, which can be directed to the inner or outer diameters of the swirler axial passage in order to reduce the occurrence of flame holding on the fuel nozzle assembly. Additionally, while the cross-sectional view is shown nearer to an exit arrangement for a swirler assembly, it should be appreciated that the cross-section can be defined anywhere between the leading edge and the trailing edge of the particular vane, and it is further contemplated that such cross-sectional variation can occur in the direction extending from a leading edge to a trailing edge, as opposed to or in complement with the variation extending between the forward and aft walls <NUM>, <NUM>.

A variable profile for the vanes extending between a forward and an aft wall can provide for defining different velocity profiles for the swirling air emitted from the swirler. The variable velocity profiles can be utilized to prevent flame holding against portions of the fuel nozzle assembly, and the profiles can be utilized to develop complex flow profiles to prevent flame holding. Furthermore, different velocity profiles can be used to control mixing of fuel and air in the fuel nozzle assembly, as well as in the primary zone of the downstream combustor.

In another example, it is contemplated that the vanes, such as those shown in <FIG>, can include a varying cross-sectional in the radial direction, being orthogonal to a direction extending between the forward wall and the aft wall. In this way, similar to that disclosed in the axial direction, the vane can converge, diverge, remain constant, or any combination thereof in the radial direction. Further yet, it is contemplated that the vanes can include a varying cross section in both the radial and the axial direction. For example, a vane can be converging from the forward wall to the aft wall, in the axial direction, while that same vane can be diverging in the radial direction, orthogonal to the axial direction. In this way, it should be appreciated that the profile for the vane can be used to determine or define a velocity profile, which can be tailored to the fuel nozzle assembly, or the particular fuel type, which can be used to reduce or eliminate flame holding or flashback, as well as mixing fuel and air to increase efficiency.

<FIG> shows a fuel nozzle assembly <NUM> with a swirler <NUM> circumscribing a fuel nozzle <NUM>. The swirler <NUM> includes an axial passage <NUM> that exhausts about the fuel nozzle <NUM>. The axial passage <NUM> can include a converging portion <NUM>. The axial passage <NUM> can be spaced from the fuel nozzle <NUM> by a swirler wall <NUM>. The swirler wall <NUM> can include an angled portion <NUM> which defines the converging portion <NUM>. The converging portion <NUM> provides for increasing the velocity for the swirler air exhausted from the axial passage <NUM>, which prevents flame holding on the fuel nozzle assembly <NUM>. A throat <NUM> is defined in the passage downstream of the fuel nozzle <NUM> and upstream of a flare cone <NUM> where the flow is accelerated to prevent the flame from flashing back on the fuel nozzle <NUM>. The location of the throat <NUM> from the fuel nozzle <NUM> can be from 0D to 30D where D is the diameter of a fuel orifice hole <NUM> at the end of the fuel nozzle <NUM>, and in one example, D can be the diameter of the smallest fuel orifice hole.

A protuberance <NUM> can be formed in the swirler <NUM>. The protuberance can be rounded or linear, or combinations thereof, while any suitable shape is contemplated. The protuberance <NUM> defines a converging cross-section downstream of the angled portion <NUM>, which can define throat <NUM> as the smallest cross-sectional area for the fuel nozzle assembly <NUM> downstream of the fuel nozzle <NUM> and upstream of the flare cone <NUM>. The protuberance <NUM> can be positioned downstream from the fuel nozzle <NUM> by between 0D and 30D, where D is the diameter of the fuel orifice hole <NUM>, and here 0D is aligned with the end of the fuel nozzle.

<FIG> includes a fuel nozzle assembly <NUM> with a swirler <NUM> circumscribing a fuel nozzle <NUM>. The swirler <NUM> includes an axial passage <NUM>, which includes a converging portion <NUM> defining a converging section exhausting about the fuel nozzle <NUM>. The swirler <NUM> includes a downstream housing portion <NUM> extending aft of the fuel nozzle <NUM>, defining a truncated nozzle <NUM> encasing a mix of air from the swirler <NUM> and fuel from the fuel nozzle <NUM>. The truncated nozzle <NUM> provides for additional space between the truncated nozzle <NUM> and an exterior flare cone <NUM>, which provides space for an acoustic damper <NUM> between the truncated nozzle <NUM> and the flare cone <NUM>. The converging cross-sectional area defined by the truncated nozzle <NUM> accelerates the flow of the fuel and air emitted from the fuel nozzle <NUM> and the swirler <NUM> to prevent flame holding or flashback, while the damper <NUM> can be utilized to reduce vibration generated by the fuel nozzle assembly <NUM>, providing further flame control to prevent flame holding or flashback. In this way, the damper <NUM> can be an acoustic damper, which can dampen the sound generated by the engine for quieter operation, as well as reducing or absorbing vibrational energy with the flare cone <NUM> and damper <NUM>. The damper volume can be the same or different for different fuel nozzle assemblies <NUM> in annular arrangement about a combustor, to address broader range of combustion dynamic frequencies. It is possible that there can be partitioning of volume within each individual damper volume placed around swirler <NUM>, where discrete volumes can be tuned to particular frequencies. The damper <NUM> can be extended above flare cone <NUM> into the combustion chamber.

It should be appreciated that the flare can be made as diverging, constant, or converging in the flow direction, which can prevent flame holding or flashback, as well as expand the mixture of fuel and air, which can improve efficiency and reduce emissions. In another example, it is contemplated that there is no flare.

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 can fail to provide durability to utilize such fuels.

As will be appreciated from the description herein, the aspects can be interchanged or mixed, and that the disclosure is not limited to the embodiments described herein. A person having ordinary skill in the art would recognize that the aspects described herein can be interchanged, combined, added, or otherwise mixed to form additional embodiments.

Claim 1:
A fuel nozzle and swirler assembly (<NUM>) for an engine (<NUM>), the fuel nozzle and swirler assembly (<NUM>) comprising:
a fuel nozzle (<NUM>) including a fuel passage (<NUM>) defining a longitudinal axis (<NUM>);
a swirler (<NUM>) comprising:
a forward wall (<NUM>),
an aft wall (<NUM>) spaced from the forward wall (<NUM>) to define a swirler passage (<NUM>) therebetween,
a set of vanes (<NUM>), provided in the swirler passage (<NUM>) extending between the forward wall (<NUM>) and the aft wall (<NUM>), the set of vanes (<NUM>) configured to impart a tangential component to a volume of fluid passing through the swirler (<NUM>),
wherein each vane (<NUM>) of the set of vanes (<NUM>) turns from a radial orientation at the forward wall (<NUM>) to a tangential orientation at the aft wall (<NUM>), and
a flare cone (<NUM>) extending from the swirler and arranged at an angle (<NUM>) relative to the longitudinal axis (<NUM>);
characterized in that
the swirler (<NUM>) circumscribes the fuel nozzle (<NUM>).