Patent Description:
Aircraft turbine engines, such as those that power modern commercial and military aircraft, include a compressor section to pressurize a supply of air, a combustor section to burn a fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases to generate thrust. The combustor section generally includes a plurality of circumferentially distributed fuel injectors that project toward a combustion chamber to supply fuel to be mixed and burned with the pressurized air. Aircraft turbine engines typically include a plurality of centralized staging valves in combination with one or more fuel supply manifolds that deliver fuel to the fuel injectors.

Each fuel injector typically has an inlet fitting connected to the manifold at the base, a conduit connected to the base fitting, and a nozzle connected to the conduit to spray the fuel into the combustion chamber. Appropriate valves or flow dividers are provided to direct and control the flow of fuel through the nozzle.

Some current aircraft fuel injectors are configured for and optimized for dual fuel (e.g., No. <NUM> Fuel Oil and Methane) with water injection to reduce NOx. As the aircraft industry transitions away from using hydrocarbon-based fuels, there is a desire to mix hydrogen with Methane at very high levels, up to and including <NUM>% hydrogen. Because of the high flame speeds and reaction rates of hydrogen, flashback can occur at high pressure and temperature allowing the flame to attach on the gas fuel swirl vanes causing damage. As such, improved systems may be necessary to implement hydrogen use in aircraft combustion systems.

<CIT> relates to an air/fuel premixer for a gas turbine suitable for use with hydrogen containing fuels.

According to the invention, a fuel injector for a gas turbine engine is provided as claimed in claim <NUM>.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the center body comprises inner path vanes arranged on the exterior surface thereof, the inner path vanes arranged within the inner airflow passage to impart a swirl to a fluid passing therethrough.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the intermediate housing includes a gas swirler vane assembly arranged within the second fluid passage to impart a swirl to a fluid passing through the second fluid passage.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the second fluid passage comprises an accelerating passage defined downstream of the gas swirler vane assembly.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the second fluid passage comprises an accelerating passage at an outlet of the second fluid passage.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the outer housing includes one or more outer path vanes arranged within the outer airflow passage to impart a swirl to a fluid passing through the outer airflow passage.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the first fluid passage is configured to receive a liquid fuel.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the liquid fuel comprises water.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the second fluid passage is configured to receive a gaseous fuel.

In addition to one or more of the features described above, or as an alternative, further embodiments of the fuel injector may include that the gaseous fuel comprises hydrogen.

Some embodiments of the invention are claimed in the dependent claims.

It should be understood, however, the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.

The illustrative, example gas turbine engine <NUM> is a two-spool turbofan engine that generally incorporates a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM>, and a turbine section <NUM>. The fan section <NUM> drives air along a bypass flow path B, while the compressor section <NUM> drives air along a core flow path C for compression and communication into the combustor section <NUM>. The core flow path C directs compressed air into the combustor section <NUM> for combustion with a fuel. Hot combustion gases generated in the combustor section <NUM> are expanded through the turbine section <NUM>. Although depicted as a turbofan gas turbine engine, it should be understood that the concepts described herein are not limited to turbofan engines and these teachings could extend to other types of engines.

The gas turbine engine <NUM> generally includes a low speed spool <NUM> and a high speed spool <NUM> mounted for rotation about an engine centerline longitudinal axis A. The low speed spool <NUM> and the high speed spool <NUM> may be mounted relative to an engine static structure <NUM> via several bearing systems <NUM>. It should be understood that other bearing systems <NUM> may alternatively or additionally be provided.

The inner shaft <NUM> can be connected to the fan <NUM> through a geared architecture <NUM> to drive the fan <NUM> at a lower speed than the low speed spool <NUM>. The high speed spool <NUM> includes an outer shaft <NUM> that interconnects a high pressure compressor <NUM> and a high pressure turbine <NUM>. In this embodiment, the inner shaft <NUM> and the outer shaft <NUM> are supported at various axial locations by bearing systems <NUM> positioned within the engine static structure <NUM>.

A combustor <NUM> is arranged between the high pressure compressor <NUM> and the high pressure turbine <NUM>. A mid-turbine frame <NUM> may be arranged generally between the high pressure turbine <NUM> and the low pressure turbine <NUM>. The mid-turbine frame <NUM> can support one or more bearing systems <NUM> of the turbine section <NUM>. The mid-turbine frame <NUM> may include one or more airfoils <NUM> that extend within the core flow path C.

The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via the bearing systems <NUM> about the engine centerline longitudinal axis A, which is co-linear with their longitudinal axes. The core airflow is compressed by the low pressure compressor <NUM> and the high pressure compressor <NUM>, is mixed with fuel and burned in the combustor <NUM>, and is then expanded across the high pressure turbine <NUM> and the low pressure turbine <NUM>. The high pressure turbine <NUM> and the low pressure turbine <NUM> rotationally drive the respective high speed spool <NUM> and the low speed spool <NUM> in response to the expansion.

The pressure ratio of the low pressure turbine <NUM> can be pressure measured prior to the inlet of the low pressure turbine <NUM> as related to the pressure at the outlet of the low pressure turbine <NUM> and prior to an exhaust nozzle of the gas turbine engine <NUM>. In one non-limiting embodiment, a bypass ratio of the gas turbine engine <NUM> is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about five (<NUM>:<NUM>). It should be understood, however, that the above parameters are only examples of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines, including direct drive turbofans.

In an embodiment of the gas turbine engine <NUM>, a significant amount of thrust may be provided by the bypass flow path B due to the high bypass ratio. The fan section <NUM> of the gas turbine engine <NUM> is designed for a particular flight condition-typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>,<NUM> meter). This flight condition, with the gas turbine engine <NUM> at its best fuel consumption, is also known as bucket cruise Thrust Specific Fuel Consumption (TSFC). TSFC is an industry standard parameter of fuel consumption per unit of thrust.

Fan Pressure Ratio is the pressure ratio across a blade of the fan section <NUM> without the use of a Fan Exit Guide Vane system. The low Fan Pressure Ratio according to one non-limiting embodiment of the example gas turbine engine <NUM> is less than <NUM>. Low Corrected Fan Tip Speed is the actual fan tip speed divided by an industry standard temperature correction of [(Tram ° R)/(<NUM>° R)]<NUM>, where Tram represents the ambient temperature in degrees Rankine. The Low Corrected Fan Tip Speed according to one non-limiting embodiment of the example gas turbine engine <NUM> is less than about <NUM> feet per second (fps) (<NUM> meters per second (m/s)).

Each of the compressor section <NUM> and the turbine section <NUM> may include alternating rows of rotor assemblies and vane assemblies (shown schematically) that carry airfoils that extend into the core flow path C. For example, the rotor assemblies can carry a plurality of rotating blades <NUM>, while each vane assembly can carry a plurality of vanes <NUM> that extend into the core flow path C. The blades <NUM> of the rotor assemblies create or extract energy (in the form of pressure) from the core airflow that is communicated through the gas turbine engine <NUM> along the core flow path C. The vanes <NUM> of the vane assemblies direct the core airflow to the blades <NUM> to either add or extract energy.

<FIG> illustrates an industrial turbine engine architecture <NUM> that is located within an enclosure <NUM>. The industrial turbine engine architecture <NUM> may be similar to that shown and described above with respect to <FIG>. The industrial turbine engine architecture <NUM> may be configured with embodiments and features described herein.

Turning now to <FIG>, a combustor section <NUM> for use in an aircraft or industrial turbine engine is schematically shown. The combustor section includes a combustor <NUM> with an outer combustor wall assembly <NUM>, an inner combustor wall assembly <NUM>, and a diffuser case <NUM>. The outer combustor wall assembly <NUM> and the inner combustor wall assembly <NUM> are spaced apart such that a combustion chamber <NUM> is defined therebetween. The combustion chamber <NUM> may be generally annular in shape.

The outer combustor wall assembly <NUM> is spaced radially inward from an outer diffuser case <NUM> of the diffuser case <NUM> to define an outer annular plenum <NUM>. The inner combustor wall assembly <NUM> is spaced radially outward from an inner diffuser case <NUM> of the diffuser case <NUM> to define an inner annular plenum <NUM>. It should be understood that although a particular combustor arrangement is illustrated, other combustor types, such as can combustors, with various combustor liner/wall arrangements will also benefit from embodiments of the present disclosure.

The combustor wall assemblies <NUM>, <NUM> contain the combustion products for direction toward a turbine section <NUM> of a turbine engine. Each combustor wall assembly <NUM>, <NUM> generally includes a respective support shell <NUM>, <NUM> which supports one or more liner panels <NUM>, <NUM>, respectively mounted to a hot side of the respective support shell <NUM>, <NUM>. Each of the liner panels <NUM>, <NUM> may be generally rectilinear and manufactured of, for example, a nickel based super alloy, ceramic or other temperature resistant material and are arranged to form a liner array. In one disclosed non-limiting embodiment, the liner array may include a multiple of forward liner panels and a multiple of aft liner panels that are circumferentially staggered to line the hot side of the outer support shell <NUM>. A multiple of forward liner panels and a multiple of aft liner panels may be circumferentially staggered to line the hot side of the inner shell <NUM>.

The combustor <NUM> further includes a forward assembly <NUM> immediately downstream of a compressor section of the engine to receive compressed airflow therefrom. The forward assembly <NUM> generally includes an annular hood <NUM> and a bulkhead assembly <NUM> which locate a multiple of fuel nozzles <NUM> (one shown) and a multiple of swirlers <NUM> (one shown). Each of the swirlers <NUM> is mounted within an opening <NUM> of the bulkhead assembly <NUM> to be circumferentially aligned with one of a multiple of annular hood ports <NUM>. Each bulkhead assembly <NUM> generally includes a bulkhead support shell <NUM> secured to the combustor wall assembly <NUM>, <NUM>, and a multiple of circumferentially distributed bulkhead liner panels <NUM> secured to the bulkhead support shell <NUM>.

The annular hood <NUM> extends radially between, and is secured to, the forwardmost ends of the combustor wall assemblies <NUM>, <NUM>. The annular hood <NUM> forms the multiple of circumferentially distributed hood ports <NUM> that accommodate the respective fuel nozzle <NUM> and introduce air into the forward end of the combustion chamber <NUM>. Each fuel nozzle <NUM> may be secured to the diffuser case module <NUM> and project through one of the hood ports <NUM> and the respective swirler <NUM>.

In operation, the forward assembly <NUM> introduces core combustion air into the forward section of the combustion chamber <NUM> while the remainder enters the outer annular plenum <NUM> and the inner annular plenum <NUM>. The multiple of fuel nozzles <NUM> and adjacent structure generate a blended fuel-air mixture that supports stable combustion in the combustion chamber <NUM>.

Opposite the forward assembly <NUM>, the outer and inner support shells <NUM>, <NUM> are mounted to a first row of Nozzle Guide Vanes (NGVs) <NUM>. The NGVs <NUM> are static engine components which direct the combustion gases onto turbine blades in a turbine section of the engine to facilitate the conversion of pressure energy into kinetic energy. The combustion gases are also accelerated by the NGVs <NUM> because of a convergent shape thereof and are typically given a "spin" or a "swirl" in the direction of turbine rotation.

Although <FIG> is illustrative of a specific combustor section configuration, those of skill in the art will appreciate that other combustor configurations may benefit from embodiments of the present disclosure. For example, can combustors, annular combustors, can-annular combustors, and other types of combustors may implement or be configured with embodiments of the present disclosure.

Referring now to <FIG>, schematic illustrations of a fuel injector <NUM> for use in combustors and combustor sections of turbine engines and in accordance with embodiments of the present disclosure are illustratively shown. The fuel injector <NUM> may be implemented in the above described combustors and engine configurations, and variations thereon. <FIG> illustrates a side elevation view of the fuel injector <NUM> and <FIG> illustrates a cross-sectional view of the fuel injector <NUM>.

As shown, the fuel injector <NUM> includes a first inlet <NUM> and a second inlet <NUM> defined by an inlet housing <NUM>, a support housing <NUM>, and a nozzle assembly <NUM>. In some embodiments, and as shown, the first inlet <NUM> is arranged transverse to the second inlet <NUM>. The inlet housing <NUM> is received within the support housing <NUM> and a tube <NUM> extends through the housings <NUM>, <NUM> (e.g., as shown <FIG>).

The first inlet <NUM> may receive a first fluid such as a liquid and the second inlet <NUM> may receive a second fluid such as a gas. The fuel injector <NUM> provides for concentric passages for the first fluid and the second fluid. For example, in some embodiments, the first fluid may be a liquid state of Jet-A, diesel, JP8, water and combinations thereof, and the second fluid may be a gas, such as natural gas or methane. Each of the fluids are communicated through separate concentric passages within the fuel injector <NUM> such that gas turbine engine readily operates on either fuel or combinations thereof. For example, in the illustrative embodiment, the tube <NUM> provides a barrier between the first fluid (e.g., within the tube <NUM> and sourced from the first inlet <NUM>) and the second fluid (e.g., in a space around the tube <NUM> and sourced from the second inlet <NUM>). As noted, the first fluid may be in a liquid state and the second fluid may be in a gaseous state.

The tube <NUM> is secured within the inlet housing <NUM> at a first end <NUM> and secured in or to the nozzle assembly <NUM> at a second end <NUM>. The connection at the first end <NUM> may include a seal, such as an O-ring, or the like. The connection at the second end <NUM> may be via a braze, weld, thread, or other attachment to the nozzle assembly <NUM>. The tube <NUM> defines a first fluid passage <NUM> within the tube <NUM> and a second fluid passage <NUM> defined between an exterior surface of the tube <NUM> and an interior surface of the housings <NUM>, <NUM>. The second fluid passage <NUM> may be an annular passage that surrounds the tube <NUM> along a length of the fuel injector <NUM>. The second fluid passage <NUM> defined within the housings <NUM>, <NUM> and around the tube <NUM> provides for a buffer or heat shield to minimize or prevent coking of the fluid passing through the first fluid passage <NUM> within the tube <NUM>. The first fluid and the second fluid may be mixed and joined together at the nozzle assembly <NUM>.

Referring now to <FIG>, a schematic cross-sectional view of a nozzle assembly <NUM>. The nozzle assembly <NUM> includes a swirler <NUM> with various components arranged within and relative to the swirler <NUM>. The nozzle assembly <NUM> includes an outer air swirler <NUM>, an inner air swirler <NUM>, and an air inflow tube <NUM> with a helical inflow vane assembly <NUM> arranged along a nozzle axis F. The nozzle assembly <NUM> includes a structure similar to the fuel injector described above, with a tube <NUM> arranged within a housing <NUM> and defining a first fluid passage <NUM> and a second fluid passage <NUM>.

An outer wall <NUM> of the outer air swirler <NUM> includes a multiple of axial slots <NUM> which receive airflow therethrough. An outer annular air passage <NUM> is defined around the axis F and within the outer air swirler <NUM>. An annular fuel gas passage <NUM> is defined around the axis F and between the outer air swirler <NUM> and the inner air swirler <NUM>. The annular fuel gas passage <NUM> receives fluid (e.g., gaseous fuel) from within the second fluid passage <NUM>. An annular liquid passage <NUM> is defined around the axis F and within the inner air swirler <NUM>. The annular liquid passage <NUM> receives fluid (e.g., liquid fuel) from the first fluid passage <NUM> of the tube <NUM>. A central air passage <NUM> is defined along the axis F within the air inflow tube <NUM>.

The outer annular air passage <NUM> is generally defined between the outer wall <NUM> and an inner wall <NUM> of the outer air swirler <NUM>. An end section <NUM> of the outer wall <NUM> extends beyond an end section <NUM> of the inner wall <NUM> and the annular liquid passage <NUM>. The end section <NUM> of the outer wall <NUM> includes a convergent section 534A that transitions to a divergent section 534B and terminates at a distal end 534C. That is, the end section <NUM> defines a convergent-divergent nozzle with an essentially asymmetric hourglass-shape downstream of the inner air swirler <NUM> and the air inflow tube <NUM>.

In one illustrative and non-limiting embodiment, the divergent section 534B defines an angle D of between about zero to thirty (<NUM>-<NUM>) degrees with respect to the axis F. The end section <NUM> defines a length X which. The length X, in this non-limiting example, may be about <NUM>-<NUM> inches (<NUM>-<NUM>) in length along the axis F with a filming region R of about <NUM>-<NUM> inches (<NUM>-<NUM>). That is, the length of the filming region R defines from about <NUM>-<NUM>% of the length X of the end section <NUM>. The filming region R may extend to the distal end 534C of the divergent section 534B. It should be appreciated that various other geometries of the outer air swirler <NUM> may benefit from embodiments described herein.

The end section <NUM> of the inner wall <NUM> abuts an outer wall <NUM> of the inner air swirler <NUM> to defines a multiple of angled slots or vanes <NUM>, which may be arranged and oriented as skewed slots to form an axial swirled exit for the annular gas passage <NUM>. That is, the annular gas passage <NUM> terminates with the multiple of angled slots <NUM> to direct the fuel gas axially and imparts a swirl thereto. In other embodiments, the annular gas passage <NUM> may terminates with a multiple of openings that are generally circular passages. It should be appreciated that other geometries may alternatively be provided without departing from the scope of the present disclosure. The annular gas passage <NUM> communicates essentially all, e.g., about one hundred (<NUM>) percent of the fuel gas through the multiple of angled slots <NUM>. The multiple of angled slots <NUM> will decrease the injection area and increase axial swirl momentum to increase circumferential uniformity and total air swirl due to the angle of gas injection and increase in air stream mixing downstream of the nozzle assembly <NUM> to facilitate fuel-air mixing. Each of the multiple of angled slots <NUM> may be arranged as skewed quadrilaterals in shape. In some such embodiments, the multiple of angled slots <NUM> may be skewed at an angle between about fifty to sixty degrees (<NUM>°-<NUM>°) around the axis F. The outer wall <NUM> and an inner wall <NUM> of the inner air swirler <NUM> define the annular liquid passage <NUM>. An end section <NUM> of the outer wall <NUM> and an end section <NUM> of the inner wall <NUM> may be turned radially inward toward the axis F to direct the liquid at least partially radially inward.

The air inflow tube <NUM> is mounted within the inner wall <NUM> and includes the upstream helical inflow vane assembly <NUM> to swirl an airflow passing therethrough. Due in part to the swirled airflow through the air inflow tube <NUM>, the liquid spray expands from the annular liquid passage <NUM> and impacts upon the filming region R to re-film/re-atomize the fluids as they are injected into a combustion chamber. The increased liquid injection recession causes large drops to re-film/re-atomization on the larger wall surface of the divergent section 534B, resulting in smaller drop size and higher penetration which increases a water vaporization rate as well as positioning water in desirable locations for the combustion process. The reduced water drop size and the effective utilization of water facilitates a decrease in NOx emissions with reduced water injection (i.e. lower water-to-fuel ratio).

The above described fuel injector may be useful for dual-fuel operation (e.g., No. <NUM> Fuel Oil and Methane) with water injection to reduce NOx. For example, water may be provided through the first inlet and the tube and mixed with a gas fuel, or water may be mixed with a liquid fuel (e.g., Jet A, No. <NUM> Fuel Oil, etc.). The gas fuel may be methane or propane, and in some embodiments a mixture of methane and hydrogen may be provided through the second inlet and passed through the second fluid passage around the tube. It may be advantageous to increase the amount of hydrogen that is used in such systems, such as mixing the hydrogen with methane at very high levels up to and including <NUM>% hydrogen (e.g., no methane at the maximum configuration). However, because of the high flame speeds and reaction rates of hydrogen, flashback can occur at high pressure and temperature allowing the flame to attach on the gas fuel swirl vanes causing damage (e.g., angled slots <NUM>). That is, by increasing the amount of hydrogen within the gas fuel, flashback or other negative impacts may occur.

For example, referring now to <FIG> a schematic illustration of flow of fluids through a nozzle assembly <NUM> in accordance with an embodiment of the present disclosure is shown. The nozzle assembly <NUM> may be similar to that shown and described above, providing dual-fuel injection of fuel into a combustion chamber of a turbine engine. A first fluid <NUM> is provided through a first fluid passage and a second fluid <NUM> is provided through a second fluid passage, as described above. Air may be introduced to the system to swirl, mix, and provide oxygen for the combustion process. In <FIG>, the air is indicated as a third fluid <NUM>. The third fluid <NUM> (e.g., air) may be supplied into the nozzle assembly <NUM> through an air inflow tube <NUM>. The air within the air inflow tube <NUM> may be swirled or rotated as it passes over or through a helical inflow vane assembly <NUM>. As the fuel fluids <NUM>, <NUM> (e.g., gas and liquid) are passed through the nozzle assembly <NUM>, the flows will be joined together and mixed with the third fluid <NUM> (air). Some of the air <NUM> may be directed through a swirler <NUM> arranged at the outlet of the nozzle assembly <NUM>.

As shown, the second fluid <NUM> may be passed through an annular gas passage <NUM>. As the second fluid <NUM> reaches the outlet end of the nozzle assembly <NUM>, it will be passed through a plurality of angled slots <NUM>. The angled slots <NUM> may be defined by vanes or other angled walls that are configured to rotate and swirl the second fluid <NUM> as it is mixed with the other fluids <NUM>, <NUM>. When hydrogen is introduced into the second fluid <NUM> (e.g., mixture of hydrogen with other fuel, or hydrogen only), the hydrogen may be disrupted at the angled slots <NUM> and cause vane wakes that can negatively impact the nozzle assembly <NUM> and/or the combustion provided thereby.

Referring now to <FIG>, schematic illustrations of a nozzle assembly <NUM> are shown. The nozzle assembly <NUM> may be similar to that shown and described above, and thus similar features may not be labeled or described in further detail. The nozzle assembly <NUM> is configured to receive a first fluid <NUM> through a first fluid passage <NUM>, a second fluid <NUM> through a second fluid passage <NUM>, and a third fluid <NUM> through a third fluid passage <NUM>. In this configuration, the first and second fluid passages <NUM>, <NUM> are structurally separate, as compared to the above described embodiments where the second fluid passage is arranged within the first fluid passage, however, the functionality thereof is substantially the same, as the first and second fluids will be mixed at an outlet <NUM> of the nozzle assembly <NUM>.

In this configuration, the third fluid passage <NUM> is an air inflow tube having a center body <NUM> installed therein. The center body <NUM> includes one or more inner path vanes <NUM> arranged about an exterior of the center body <NUM>. The center body <NUM> is positioned within the third fluid passage to swirl and direct part of the third fluid <NUM> toward the radially outward edges of the third flow passage <NUM>. The center body <NUM> may be provided to stabilize a flame at the outlet <NUM> of the nozzle assembly <NUM>. The inner path vanes <NUM> of the center body <NUM> will cause the flow to transition from an axial flow along an axis F of the nozzle assembly <NUM> to a circumferential or tangential flow and thus impart or induce a swirl within the third fluid. In this configuration, the third flow passage <NUM> is separated into two flows (e.g., 712a, 712b). As shown, an inner airflow passage 712a is defined between an exterior of the center body <NUM> and an inner wall of the third flow passage <NUM> and an outer airflow passage 712b is arranged or defined radially outward therefrom. As noted, a swirl may be introduced to the third fluid <NUM> by the inner path vanes <NUM> of the center body <NUM>. The inner path vanes <NUM> are arranged within the inner airflow passage 712a and obstruct and impart a swirl to a portion of the third fluid <NUM> passing through the inner airflow passage 712a. In the outer airflow passage 712b, the third fluid <NUM> may be rotated or swirled as it passes through outer path vanes <NUM> proximate the outlet <NUM>. This swirling at the outer path vanes <NUM> may serve to impart a swirl or rotation to the second fluid <NUM> as the flow enters the region of the outlet <NUM>.

<FIG> illustrates the flow of fluids through the nozzle assembly <NUM>. As shown, the first fluid <NUM> will be suppled through the first fluid passage <NUM>. The first fluid passage <NUM> will extend along a tube or the like, and then the first fluid <NUM> will enter the nozzle assembly <NUM> and turn to an axial flow in a direction along the axis F. The first fluid passage <NUM> is defined, in part, by a wall of the third fluid passage <NUM>, and in this embodiment is arranged radially inward (relative to the axis F) from the outer airflow passage 712b. The first fluid <NUM> will be injected into a combustion chamber at the outlet <NUM> between an outlet flow of the inner airflow passage 712a and an outlet flow of the outer airflow passage 712b. As each of the inner airflow passage 712a and the outer airflow passage 712b include swirling elements (inner path vanes <NUM> and outer path vanes <NUM>), the first fluid <NUM> will be swirled and mixed with the third fluid <NUM>. That is, an inner air flow 722a and an outer air flow 722b of the third fluid <NUM> will mix with the first fluid <NUM> at the outlet <NUM>. In this configuration, the second fluid <NUM> will travel along the second fluid passage <NUM> and be radially injected into the outer airflow passage 712b downstream of the outer path vanes <NUM> through apertures <NUM>, and thus be swirled. Further, because the second fluid <NUM> is mixed with the third fluid <NUM> in the outer flow passage 712b, the three fluids <NUM>, <NUM>, <NUM> will mix at the outlet <NUM> of the nozzle assembly <NUM>. As shown in <FIG>, a swirler guide assembly <NUM> may be provided to direct cooling air <NUM> about the outlet <NUM> of the nozzle assembly <NUM>.

As the three fluids are mixed and swirled at the outlet <NUM>, the mixing and swirling fluids may be combusted. The center body <NUM> provides for a mechanism to increase a flow velocity of the third fluid <NUM> passing through the inner airflow passage 712a. It may be advantageous to have hydrogen mixed into or form the entirety of the second fluid <NUM>. However, due to the properties of hydrogen, a recirculation of the mixture of fluids at the outlet <NUM> and/or wakes from vanes <NUM> and the like in various flow paths may cause excessive temperatures within the nozzle assembly <NUM>.

For example, as shown in <FIG>, a flow diagram illustrates a low velocity region <NUM> at an end wall <NUM> of the center body <NUM>. A low velocity region <NUM> also exists at the location where the second fluid is injected into the third fluid downstream of the outer path vanes <NUM>. These low velocity regions <NUM>, <NUM> may allow for the hydrogen to attach, stagnate, and potentially combust at locations within the nozzle assembly <NUM>, rather than in a combustion chamber.

Turning now to <FIG>, schematic illustrations of a nozzle assembly <NUM> in accordance with an embodiment of the present invention are shown. The nozzle assembly <NUM> is a multi-fluid combustor nozzle assembly for use in a turbine engine system. The nozzle assembly <NUM> is configured to mix three fluids, including a first fluid <NUM> (e.g., a liquid fuel), a second fluid <NUM> (e.g., a gaseous fuel), and a third fluid <NUM> (e.g., air). The first fluid <NUM> is provided along a first fluid passage <NUM>, the second fluid <NUM> is provided along a second fluid passage <NUM>, and the third fluid <NUM> is provided along a third fluid passage <NUM> (labeled as 812a, 812b, 812c) defined within an air inflow tube <NUM>.

A center body <NUM> is arranged within the air inflow tube <NUM>. Similar to the embodiment of <FIG>, the center body <NUM> includes in this embodiment inner path vanes <NUM> that are arranged to swirl a portion of the third fluid that flows along an inner airflow passage 812a. The third fluid <NUM> will also flow along an outer airflow passage 812b, which includes outer path vanes <NUM> configured to swirl the air in the outer airflow passage 812b. Rather than a solid body (as in the embodiment of <FIG>), the center body <NUM> is a hollow body structure that defines a center body airflow passage 812c therethrough. As such, the center body <NUM> includes an open first end <NUM> and a partially open, airflow cooled second end <NUM> such that airflow may enter the center body <NUM> at the first end <NUM>, flow through an interior of the center body <NUM>, and exit through/out the second end <NUM>. The second end <NUM> includes a double-walled configuration, with an impingement plate <NUM> and an effusion plate <NUM> arranged at the second end <NUM> of the center body <NUM>. That is, the second end <NUM> includes an air cooled array of impingement holes in the impingement plate <NUM> and effusion cooling holes in the effusion plate <NUM> at the downstream end (second end <NUM>) of the center body <NUM>. The impingement plate <NUM> includes a plurality of apertures that are arranged to direct the airflow to impinge upon the effusion plate <NUM> and provide impingement cooling thereto. The effusion plate <NUM> similarly includes a plurality of apertures, and directs an effusion flow of air out the second end <NUM> of the center body <NUM>. As result of the open first end <NUM> and the air cooled second end <NUM> of the center body <NUM>, the nozzle assembly <NUM> includes a substantially non-swirled, axial flow of air along an axis F of the nozzle assembly <NUM>. This axial flow through the center body <NUM> will be substantially unswirled as it exits the center body <NUM> through the effusion plate <NUM>, and thus may be able to push any fuel components (e.g., hydrogen) or high temperature gases away from the effusion plate <NUM> to thus reduce metal temperatures thereof.

In addition to the hollow body center body <NUM>, the nozzle assembly <NUM> includes a modified flow path for the second fluid <NUM>. The second fluid passage <NUM> is similar to the configuration of <FIG>, with the second fluid passage <NUM> being defined around the first fluid passage <NUM>. Further, the second fluid passage <NUM> enters the nozzle assembly <NUM> and is arranged radially inward from the outer airflow passage 812b and is arranged parallel with the axis F. The second fluid passage <NUM>, in this embodiment, includes a vane swirler assembly <NUM> that imparts a swirl to the second fluid <NUM>. The second fluid <NUM> may then pass through an accelerating passage <NUM> downstream from the vane swirler assembly <NUM>, prior to injection at the outlet <NUM> of the nozzle assembly <NUM> to be mixed with the other fluids <NUM>, <NUM>. The accelerating passage <NUM> of the second fluid passage <NUM> allows the flow of the second fluid <NUM> to mix out makes caused by the vane swirler assembly <NUM>, such that the flow of the second fluid <NUM> exits the second fluid passage <NUM> with a relatively uniform high velocity before it mixes with the third fluid <NUM> at the outlet <NUM> of the nozzle assembly <NUM>. The accelerating passage <NUM> may be formed as a tapering passage where the cross-sectional area, in a flow direction, reduces in the axial direction. In accordance with some non-limiting embodiments, an axial length Ap of the accelerating passage <NUM> is at least five (<NUM>) times longer than a radial height Hv of the vane swirler assembly <NUM>. This relatively long accelerating passage <NUM> allows for sufficient length or time for wakes formed from interaction with the vane swirler assembly <NUM> to mix out of the flow.

In a non-limiting example operation of the nozzle assembly <NUM>, the first fluid <NUM> may be a liquid, such as water or a mixture of liquid fuel and water, the second fluid <NUM> may be a gas, such as methane, a methane/hydrogen mix, or hydrogen, and the third fluid <NUM> may be a gas, such as air (e.g., pressurized air from a compressor section of a turbine engine). In this embodiment, as compared to the embodiment of <FIG>, the gas fuel supply (second fluid passage <NUM>) is arranged around the liquid fuel supply (first fluid passage <NUM>). The gas fuel (second fluid <NUM>) will be swirled within the second fluid passage <NUM> by means of the vane swirler assembly <NUM> and then accelerated through the accelerating passage <NUM>. As such, the gaseous fuel (second fluid <NUM>) will be ejected at the outlet <NUM> of the nozzle assembly <NUM> at a relatively high velocity. Additionally, the flow paths of the third fluid <NUM> are also different compared to the embodiment of <FIG>.

For example, the outer airflow passage 812b is moved radially outward relative to the first and second fluid passages <NUM>, <NUM> within the nozzle assembly <NUM>, as shown in <FIG>. As such, a portion of the third fluid <NUM> will be radially outward from the other fluids <NUM>, <NUM> and may be injected radially inward at the outlet <NUM> of the nozzle assembly <NUM> to guide the flows of the fluids as they enter a combustion chamber for combustion. Along this outer airflow passage 812b, outer path vanes <NUM> are moved forward (relative to an engine axis) so that the length or distance from the outer path vanes <NUM> to an outlet of the outer airflow passage 812b at the outlet <NUM> of the nozzle assembly <NUM> is increased as compared to prior configurations. For example, in some non-limiting embodiments, the axial length of the outer airflow passage 812b from the outer path vanes <NUM> to the outlet <NUM> of the nozzle assembly <NUM> may be at least five (<NUM>) times a radial height of the outer path vanes <NUM>. This increase length of the outer airflow passage 812b downstream of the outer path vanes <NUM> allows for wakes created by the outer path vanes <NUM> to mix out of the flow. To accommodate this outboard position and arrangement of fluid passages, an inlet <NUM> of the third fluid passage <NUM> (e.g., air inlet) may be enlarged to compensate for increased blockage caused by the second fluid passage <NUM> being arranged radially inward from the outer airflow passage 812b. That is, by increasing the size of the inlet <NUM>, blockage caused by the radially inward second fluid passage <NUM> may be mitigated.

Additionally, the third fluid passage (collectively <NUM>) includes the center body airflow passage 812c within the interior of the center body <NUM>. The center body airflow passage 812c provides for a substantially axial flow with no swirl, that will exit through the downstream, second end <NUM> (e.g., through the impingement plate <NUM> and the effusion plate <NUM>).

As shown in <FIG>, a flow diagram illustrates the increased flow velocities as compared to the prior configuration (e.g., shown in <FIG>). <FIG> illustrates the flow of fluids through and around the outer path vanes <NUM>, the vane swirler assembly <NUM>, and the downstream, second end <NUM> of the center body <NUM>. As shown, regions <NUM>, <NUM>, <NUM> all indicate higher flow velocities than the configuration of <FIG>. For example, in a first region <NUM> at the partially obstructed second end <NUM> of the center body <NUM>, a relatively high velocity dome of air that is ejected through the effusion plate <NUM> will prevent hydrogen from attaching to the end of the center body <NUM>. The impingement plate <NUM> provides backside cooling to the effusion plate <NUM> to prevent the end of the center body <NUM> from reaching undesirable temperatures. Also shown, in a second region, a flow of gas through the accelerating passage <NUM> downstream of the vane swirler assembly <NUM> allows for increased velocity gas (e.g., hydrogen) that has relatively smooth flow, as the vane swirler assembly <NUM> is moved away from the outlet <NUM> of the nozzle assembly <NUM>. In a third region <NUM>, where the outer path vanes <NUM> of the outer airflow passage 812b is moved away from the outlet <NUM> of the nozzle assembly <NUM>, wakes are avoided and the flow may smooth out prior to exiting at the outlet <NUM> of the nozzle assembly <NUM>.

Although <FIG> illustrate a few different mechanisms for improving operation of a nozzle assembly, it will be appreciated that the combination of the features described is not required. That is, in some embodiments of the present disclosure, a nozzle assembly may be substantially similar to that of <FIG>, but rather than a solid body center body, a hollow body center body (e.g., as shown in <FIG>) may be employed. That is, the other changes to the nozzle assembly (e.g., position of gas swirlers, position of air swirlers, arrangement of the fluid passages) may not be implemented, while still providing advantages over prior nozzle assemblies. Similarly, in some embodiments, the fluid passage modification(s) may be used without a hollow body center body. As such, the present disclosure is not limited to the specific arrangement of <FIG>, but rather such configuration is provided for simplicity and ease of introducing features as described herein.

Referring again to <FIG>, the nozzle assembly <NUM> may be formed of multiple housing arranged to define the fluid passages. For example, as shown, an inner housing <NUM> may house the center body <NUM> and define the center body airflow passage 812c within the center body <NUM> and the inner airflow passage 812a between and exterior surface of the center body <NUM> and an interior surface of the inner housing <NUM>. The inner housing <NUM> may define or form the air inflow tube <NUM>. Radially outward from the inner housing <NUM> is an intermediate housing. The inner housing <NUM> and the intermediate housing <NUM> define a portion (e.g., the axial portion) of the first fluid passage <NUM> between an exterior surface of the inner housing <NUM> and an interior surface of the intermediate housing <NUM>. The intermediate housing <NUM> may define a portion (e.g., the axial portion) of the second flow passage <NUM> and may include the vane swirler assembly <NUM> and the accelerating passage <NUM> downstream from the vane swirler assembly <NUM>. An outer housing <NUM> is arranged radially outward from the intermediate housing <NUM>. An inner surface of the outer housing <NUM> and an outer surface of the intermediate housing <NUM> define the outer airflow passage 812b and includes the outer path vanes <NUM>.

Although described above as surfaces of the respective housings <NUM>, <NUM>, <NUM> defining portions of the passages, this is not to be limiting. For example, in some embodiments, a given housing my completely define the respective passage with material/structure thereof. However, the positional relationship of the passages relative to the housing is the same, with the inner housing <NUM> arranged radially inward from the intermediate housing <NUM> and the outer housing <NUM> arranged radially outward from the intermediate housing <NUM>. Further, although shown as three separate housings <NUM>, <NUM>, <NUM> with the center body <NUM> installed within the inner housing <NUM>, such separate parts is not to be limiting. For example, in some embodiments, one or more of the housings <NUM>, <NUM>, <NUM> and/or the center body <NUM> may be integrally formed (e.g., cast, molded, additively manufactured) as a single unitary body. Further, it may be advantageous for each housing <NUM>, <NUM>, <NUM> and/or the center body <NUM> to be formed of the same or different material.

Advantageously, embodiments described herein provide for improved fuel nozzle assemblies for use with gas turbine engines (e.g., industrial or aircraft applications). In accordance with some embodiments of the present disclosure, hydrogen fuel may be efficiently introduced into turbine engine systems through the use of the nozzle assemblies described herein. Various aspects, as described above, can help prevent attaching of the hydrogen to surfaces of the nozzle assembly through increasing flow rates and reducing stagnation, wakes, and the like that can cause hydrogen to attach to surfaces. For example, by incorporating a hollow body center body into the nozzle assembly, an axial, airflow having little or now swirl may be directed along an axis of the nozzle assembly and reduce or prevent recirculation of combustion materials at the end of the center body. Another mechanism that may be employed to improve nozzle assembly performance is the change in position of the swirl vanes for both the gaseous and liquid fuels. But introducing swirl in a more upstream location, wakes and other disruptive flows may be evened out before mixing of the fuels. As such, stagnation may be avoided and attachment by hydrogen may be reduced or eliminated.

The use of the terms "a", "an", "the", and similar references in the context of description (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or specifically contradicted by context. The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. As used herein, the terms "about" and "substantially" are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, the terms may include a range of ± <NUM>%, or <NUM>%, or <NUM>% of a given value or other percentage change as will be appreciated by those of skill in the art for the particular measurement and/or dimensions referred to herein. It should be appreciated that relative positional terms such as "forward," "aft," "upper," "lower," "above," "below," and the like are with reference to normal operational attitude and should not be considered otherwise limiting.

While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, combinations, sub-combinations, or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments.

Claim 1:
A fuel injector for a gas turbine engine (<NUM>; <NUM>) comprising:
an inner housing (<NUM>) having a center body (<NUM>) installed within the inner housing (<NUM>);
an intermediate housing (<NUM>) arranged radially outward from the inner housing (<NUM>); and
an outer housing (<NUM>) arranged radially outward from the intermediate housing (<NUM>), wherein:
the center body (<NUM>) is a hollow body structure defining a center body airflow passage (812c) therethrough;
a first fluid passage (<NUM>) is partially defined between an outer surface of the inner housing (<NUM>) and an inner surface of the intermediate housing (<NUM>);
a second fluid passage (<NUM>) is partially defined within the intermediate housing (<NUM>); and
a third fluid passage (<NUM>) comprises the center body airflow passage (812c), an inner airflow passage (812a) defined between an exterior surface of the center body (<NUM>) and an interior surface of the inner housing (<NUM>), and an outer airflow passage (812b) that is defined by the outer housing (<NUM>) and radially outward from the intermediate housing (<NUM>),
wherein the center body (<NUM>) includes an open first end (<NUM>)
characterized in that
the center body (<NUM>) includes a partially obstructed, downstream second end (<NUM>);
wherein the downstream second end (<NUM>) includes a double-walled configuration, with an impingement plate (<NUM>) and an effusion plate (<NUM>) such that the second end (<NUM>) includes an air cooled array of impingement holes in the impingement plate (<NUM>) and effusion cooling holes in the effusion plate (<NUM>),
wherein the impingement plate (<NUM>) includes a plurality of apertures that are arranged to direct the airflow to impinge upon the effusion plate (<NUM>) and provide impingement cooling thereto, and
wherein the effusion plate (<NUM>) includes a plurality of apertures, and directs an effusion flow of air out the second end (<NUM>) of the center body (<NUM>).