Patent Description:
A gas turbine engine may include multiple fuel injectors for delivering fuel to a combustor for combustion with compressed air. Various types and configurations of fuel injectors are known in the art. While these known fuel injectors have various benefits, there is still room in the art for improvement. There is a need in the art, in particular, for a fuel injector which can be tuned for multiple different modes of gas turbine engine operation.

<CIT> discloses a prior art assembly according to the preamble of claim <NUM>.

According to the present invention, an assembly is provided for a gas turbine engine according to claim <NUM>.

The assembly may also include a fuel system including a fuel source and the fuel injector. The fuel system may be configured to deliver fuel from the fuel source through the fuel injector where the first fuel circuit provides a first percentage of the fuel, the second fuel circuit provides a second percentage of the fuel and the third fuel circuit provides a third percentage of the fuel. During a first mode, the first percentage and the second percentage may be greater than the third percentage. During a second mode, the third percentage may be greater than the first percentage and the second percentage.

During a third mode, the second percentage may be within ten percent of the third percentage.

During the first mode and/or the second mode, the second percentage may be greater than the first percentage.

The first fuel circuit may be configured to direct fuel out of the nozzle through the first fuel outlet along a first trajectory. The second fuel circuit may be configured to direct fuel out of the nozzle through a first of the second fuel outlets along a second trajectory that is angularly offset from the first trajectory. The third fuel circuit may be configured to direct fuel out of the nozzle through a first of the third fuel outlets along a third trajectory that is angularly offset from the first trajectory.

The second trajectory may be angularly offset from the first trajectory by a first angle. The third trajectory may be angularly offset from the first trajectory by a second angle that may be different than the first angle.

The second trajectory may be angularly offset from the first trajectory by a first angle. The third trajectory may be angularly offset from the first trajectory by a second angle that may be equal to the first angle.

The first trajectory may be coaxial with the axis.

The first fuel outlet may be coaxial with the axis.

A first of the third fuel outlets may be circumferentially aligned with a first of the second fuel outlets.

A first of the third fuel outlets may be circumferentially offset from each of the second fuel outlets.

The second fuel outlet array may be disposed radially outboard of the first fuel outlet by a first radial distance. The third fuel outlet array may be disposed radially outboard of the first fuel outlet by a second radial distance that is greater than the first radial distance.

The second fuel outlet array may be radially aligned with the third fuel outlet array.

The second fuel circuit may also include a passage that extends to a first of the second nozzle outlets. The passage may converge as the passage that extends towards the first of the second nozzle outlets.

The second fuel circuit may also include a passage that extends to a first of the second nozzle outlets. The passage may have a uniform lateral size.

A first of the second nozzle outlets may have a circular cross-sectional geometry.

A first of the second nozzle outlets may have an elongated cross-sectional geometry.

The fuel injector may also include a stem. The nozzle may project axially out from the stem along the axis to the nozzle tip. The first fuel circuit may also include a first fuel conduit within the stem and fluidly coupled to the first fuel outlet. The second fuel circuit may also include a second fuel conduit within the stem and fluidly coupled to the second fuel outlets. The third fuel circuit may also include a third fuel conduit within the stem and fluidly coupled to the third fuel outlets.

<FIG> is a side cutaway illustration of a gas turbine engine <NUM>. This gas turbine engine <NUM> extends along an axial centerline <NUM> between an upstream airflow inlet <NUM> and a downstream airflow exhaust <NUM>. The gas turbine engine <NUM> includes a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The compressor section <NUM> includes a low pressure compressor (LPC) section 29A and a high pressure compressor (HPC) section 29B. The turbine section <NUM> includes a high pressure turbine (HPT) section 31A and a low pressure turbine (LPT) section 31B.

The engine sections <NUM>, 29A, 29B, <NUM>, 31A and 31B are arranged sequentially along the axial centerline <NUM> within an engine housing <NUM>. This engine housing <NUM> includes an inner case <NUM> (e.g., a core case) and an outer case <NUM> (e.g., a fan case). The inner case <NUM> may house one or more of the engine sections 29A, 29B, <NUM>, 31A and 31B; e.g., a core of the gas turbine engine <NUM>. The outer case <NUM> may house at least the fan section <NUM>.

The fan section <NUM>, the LPC section 29A, the HPC section 29B, the HPT section 31A and the LPT section 31B each include a respective bladed rotor <NUM>-<NUM>. Each of these bladed rotors <NUM>-<NUM> includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor <NUM> is connected to a geartrain <NUM>, for example, through a fan shaft <NUM>. The geartrain <NUM> and the LPC rotor <NUM> are connected to and driven by the LPT rotor <NUM> through a low speed shaft <NUM>. The HPC rotor <NUM> is connected to and driven by the HPT rotor <NUM> through a high speed shaft <NUM>. The shafts <NUM>-<NUM> are rotatably supported by a plurality of bearings <NUM>; e.g., rolling element and/or thrust bearings. Each of these bearings <NUM> is connected to the engine housing <NUM> by at least one stationary structure such as, for example, an annular support strut.

During operation, air enters the gas turbine engine <NUM> through the airflow inlet <NUM>. This air is directed through the fan section <NUM> and into a core flowpath <NUM> and a bypass flowpath <NUM>. The core flowpath <NUM> extends sequentially through the engine sections 29A-31B; e.g., the engine core. The air within the core flowpath <NUM> may be referred to as "core air". The bypass flowpath <NUM> extends through a bypass duct, which bypasses and may be radially outboard of the engine core. The air within the bypass flowpath <NUM> may be referred to as "bypass air".

The core air is compressed by the LPC rotor <NUM> and the HPC rotor <NUM> and directed into a (e.g., annular) combustion chamber <NUM> of a (e.g., annular) combustor <NUM> in the combustor section <NUM>. Fuel is injected into the combustion chamber <NUM> by one or more fuel injectors <NUM> (one schematically shown in <FIG>) and mixed with the compressed core air to provide a fuel-air mixture. This fuel-air mixture is ignited and combustion products thereof flow through and sequentially cause the HPT rotor <NUM> and the LPT rotor <NUM> to rotate. The rotation of the HPT rotor <NUM> and the LPT rotor <NUM> respectively drive rotation of the HPC rotor <NUM> and the LPC rotor <NUM> and, thus, compression of the air received from a core airflow inlet. The rotation of the LPT rotor <NUM> also drives rotation of the fan rotor <NUM>, which fan rotor <NUM> propels bypass air through and out of the bypass flowpath <NUM>. The propulsion of the bypass air may account for a majority of thrust generated by the gas turbine engine <NUM>, e.g., more than seventy-five percent (<NUM>%) of engine thrust. The gas turbine engine <NUM> of the present disclosure, however, is not limited to the foregoing exemplary thrust ratio.

<FIG> illustrates an assembly <NUM> for the gas turbine engine <NUM>. This engine assembly <NUM> includes a fuel system <NUM> and the combustor <NUM>. The fuel system <NUM> of <FIG> includes and one or more fuel injector assemblies <NUM> (one visible in <FIG>) and a fuel source <NUM>. The fuel system <NUM> is configured to selectively deliver fuel, stored within the fuel source <NUM>, to the one or more fuel injector assemblies <NUM> for injection into the combustion chamber <NUM>.

Each fuel injector assembly <NUM> includes a respective one of the fuel injectors <NUM>. Each fuel injector assembly <NUM> may also include a swirler <NUM> and a mount <NUM> configured to couple the fuel injector <NUM> to the swirler <NUM>, where the swirler <NUM> may be coupled to a (e.g., annular) bulkhead <NUM> of the combustor <NUM>. With this arrangement, each fuel injector assembly <NUM> is configured to direct a mixture of fuel received from the fuel source <NUM> and compressed air received from the HPC section 29B (see <FIG>) into the combustion chamber <NUM> for combustion.

Referring to <FIG>, each fuel injector <NUM> includes a fuel injector stem <NUM> and a fuel injector nozzle <NUM>. A base of the injector stem <NUM> may be connected to the engine housing <NUM>; e.g., a section of the inner case <NUM>. The injector stem <NUM> projects (e.g., radially inward relative to the axial centerline <NUM>; see <FIG>) from the engine housing <NUM> into a (e.g., annular) plenum <NUM> extending about an exterior of the combustor <NUM> (see <FIG>). The injector nozzle <NUM> is connected to (e.g., formed integral with or otherwise attached to) the injector stem <NUM>. The injector nozzle <NUM> projects axially along an axis <NUM> of the injector nozzle <NUM> (e.g., generally axially along the axial centerline <NUM>; see <FIG>) out from the injector stem <NUM> to a tip <NUM> of the injector nozzle <NUM>. This nozzle tip <NUM> may be disposed within an interior bore <NUM> of the swirler <NUM> (see <FIG>) and faces towards the combustion chamber <NUM>. Alternatively, the nozzle tip <NUM> may be disposed within a port in the bulkhead <NUM>, within the combustion chamber <NUM>, etc..

Each fuel injector <NUM> also includes a plurality of internal fuel circuits 90A-C (generally referred to as "<NUM>"). These fuel circuits <NUM> may be fluidly discrete from one another within the respective fuel injector <NUM>. The first fuel circuit 90A, for example, may be completely fluidly independent (e.g., decoupled) from the second fuel circuit 90B and/or the third fuel circuit 90C within the respective fuel injector <NUM>. The second fuel circuit 90B may be completely fluidly independent (e.g., decoupled) from the first fuel circuit 90A and/or the third fuel circuit 90C within the respective fuel injector <NUM>. The third fuel circuit 90C may be completely fluidly independent (e.g., decoupled) from the first fuel circuit 90A and/or the second fuel circuit 90B within the respective fuel injector <NUM>.

The first fuel circuit 90A includes a first flowpath 92A, a first circuit inlet and at least (or only) one first outlet orifice 94A. The first flowpath 92A extend within the respective fuel injector <NUM> from the first circuit inlet to the first outlet orifice 94A. For example, an upstream section 96A of the first flowpath 92A of <FIG> extends radially (relative to the nozzle axis <NUM>) inward from the first circuit inlet, within the injector stem <NUM>, to a downstream section 98A of the first flowpath 92A. The downstream section 98A of the first flowpath 92A of <FIG> extends axially (along the nozzle axis <NUM>) from the upstream section 96A of the first flowpath 92A, within the injector nozzle <NUM>, to the first outlet orifice 94A. The upstream section 96A of the first flowpath 92A may be at least partially (or completely) formed by an upstream first conduit 100A. The downstream section 98A of the first flowpath 92A may be at least partially (or completely) formed by a downstream first conduit 102A, where the first conduits 100A and 102A may be integral segments of a common, unitary conduit or may be separate fluidly coupled conduits. At least a portion or an entirety of the downstream section 98A of the first flowpath 92A and its downstream first conduit 102A may be aligned (e.g., coaxial) with the nozzle axis <NUM>.

The first outlet orifice 94A is disposed at (e.g., on, adjacent or proximate) the nozzle tip <NUM>. The first outlet orifice 94A of <FIG>, for example, is recessed slightly axially inward (along the nozzle axis <NUM>) from a (e.g., annular, planar) center surface <NUM> of the nozzle tip <NUM>. This first outlet orifice 94A may be aligned (e.g., coaxial) with the nozzle axis <NUM>.

The first fuel circuit 90A of <FIG> is configured to direct the fuel received from the fuel source <NUM> out of the injector nozzle <NUM> through the first outlet orifice 94A (e.g., into the swirler bore <NUM> and/or into the combustion chamber <NUM>; see <FIG>) along a first trajectory 106A. This first trajectory 106A may be substantially (e.g., +/- two or five degrees) or completely parallel with the nozzle axis <NUM>. The first trajectory 106A of <FIG>, for example, is coaxial with the nozzle axis <NUM>. However, while the first trajectory 106A may be parallel to the nozzle axis <NUM>, a spray angle of the first outlet orifice 94A can be configured the cover a relatively wide range; e.g., from seventy degrees (<NUM>°) to one-hundred and twenty degrees (<NUM>°) depending upon a design trajectory of the second and the third fuel circuits 90B and 90C. The first trajectory 106A may be selected to facilitate delivery of the fuel into a first (e.g., recirculation) zone within the combustion chamber <NUM> for combustion. The first trajectory 106A, a spray pattern of the fuel out of the first outlet orifice 94A, a flowrate of the fuel through the first outlet orifice 94A as well as various other parameters of the first fuel circuit 90A may be tailored for operation of the gas turbine engine <NUM> at low power settings. The first fuel circuit 90A, for example, may be sized and shaped at the first outlet orifice 94A to facilitate relatively high fuel atomization at a relatively low fuel flow rate and/or with a relatively low airflow rate through the swirler <NUM> (see <FIG>).

The second fuel circuit 90B includes a second flowpath 92B, a second circuit inlet and one or more second outlet orifices 94B. The second flowpath 92B extend within the respective fuel injector <NUM> from the second circuit inlet to the second outlet orifices 94B. For example, an upstream section 96B of the second flowpath 92B of <FIG> extends radially (relative to the nozzle axis <NUM>) inward from the second circuit inlet, within the injector stem <NUM>, to a downstream section 98B of the second flowpath 92B. The downstream section 98B of the second flowpath 92B of <FIG> extends axially (along the nozzle axis <NUM>) from the upstream section 96B of the second flowpath 92B, within the injector nozzle <NUM>, to the second outlet orifices 94B. The upstream section 96B of the second flowpath 92B may be at least partially (or completely) formed by an (e.g., annular) upstream second conduit 100B. The downstream section 98B of the second flowpath 92B may be at least partially (or completely) formed by a (e.g., annular) downstream second conduit 102B, where the second conduits 100B and 102B may be integral segments of a common, unitary conduit or may be separate fluidly coupled conduits. The upstream section 96B of the second flowpath 92B and its upstream second conduit 100B may extend circumferentially about (e.g., completely around) the upstream section 96A of the first flowpath 92A and its upstream first conduit 100A. The downstream section 98B of the second flowpath 92B and its downstream second conduit 102B may extend circumferentially about (e.g., completely around) the downstream section 98A of the first flowpath 92A and its downstream first conduit 102A. With such a configuration, at least a portion of the second flowpath 92B within the injector stem <NUM> and/or within the injector nozzle <NUM> may be annular.

The second outlet orifices 94B are disposed at (e.g., on, adjacent or proximate) the nozzle tip <NUM>. Each of the second outlet orifices 94B of <FIG>, for example, is recessed slightly radially inward (relative to the nozzle axis <NUM>) from an (e.g., tubular, frustoconical) outer surface <NUM> of the nozzle tip <NUM>. Referring to <FIG>, the second outlet orifices 94B are arranged circumferentially about the nozzle axis <NUM> and/or the first outlet orifice 94A in an annular second outlet orifice array. This second outlet orifice array and each of its second outlet orifices 94B is disposed radially outboard of the nozzle axis <NUM> and/or the first outlet orifice 94A by a radial distance <NUM> (relative to the nozzle axis <NUM>).

The second fuel circuit 90B of <FIG> is configured to direct the fuel received from the fuel source <NUM> out of the injector nozzle <NUM> through each second outlet orifice 94B (e.g., into the swirler bore <NUM> and/or into the combustion chamber <NUM>; see <FIG>) along a respective second trajectory 106B. This second trajectory 106B is angularly offset from the nozzle axis <NUM> and/or the first trajectory 106A by a second trajectory angle <NUM> (see <FIG>); e.g., an acute angle or a right angle. This second trajectory angle <NUM> may be between fifteen degrees (<NUM>°) and ninety degrees (<NUM>°); e.g., between fifteen degrees (<NUM>°) and thirty degrees (<NUM>°), between thirty degrees (<NUM>°) and forty-five degrees (<NUM>°), between forty-five degrees (<NUM>°) and sixty degrees (<NUM>°), etc. The second trajectory angle <NUM>, for example, can be optimized based upon the spray angle of the first fuel circuit 90A and its first outlet orifice 94A. For relatively low (e.g., small) first circuit spray angles, the second trajectory angle <NUM> can be high (e.g., greater than sixty degrees (<NUM>°)) to promote fueling of the inner and outer recirculation zones, or the second trajectory angle <NUM> can be low (e.g., less than forty-five degrees (<NUM>°)) to (e.g., only) fuel the center recirculation zone. For relatively high (e.g., large) first circuit spray angles, the second trajectory angle <NUM> can be low (e.g., less than forty-five degrees (<NUM>°)) to fuel both the center and outer recirculation zones but with a discrete (secondary) versus a continuous fuel spray cone angle (first fuel circuit), or the second trajectory angle <NUM> can be high (e.g., greater than sixty degrees (<NUM>°)) to (e.g., only) fuel the outer recirculation zones. These two zones may provide significant control of the fuel spray distribution to minimize both emissions and combustor tones from idle to cruise power as exemplified in <FIG>. The second trajectory 106B may be selected to facilitate delivery of the fuel into a second (e.g., recirculation) zone within the combustion chamber <NUM> for combustion. The second trajectory 106B, a spray pattern of the fuel out of each second outlet orifice 94B, a flowrate of the fuel through each second outlet orifice 94B as well as various other parameters of the second fuel circuit 90B may be tailored for operation of the gas turbine engine <NUM> at intermediate power settings. The second fuel circuit 90B, for example, may be sized and shaped at each second outlet orifice 94B to facilitate relatively high fuel atomization at a moderate fuel flow rate and/or with a moderate airflow rate through the swirler <NUM>.

The third fuel circuit 90C includes a third flowpath 92C, a third circuit inlet and one or more third outlet orifices 94C. The third flowpath 92C extend within the respective fuel injector <NUM> from the third circuit inlet to the third outlet orifices 94C. For example, an upstream section 96C of the third flowpath 92C of <FIG> extends radially (relative to the nozzle axis <NUM>) inward from the third circuit inlet, within the injector stem <NUM>, to a downstream section 98C of the third flowpath 92C. The downstream section 98C of the third flowpath 92C of <FIG> extends axially (along the nozzle axis <NUM>) from the upstream section 96C of the third flowpath 92C, within the injector nozzle <NUM>, to the third outlet orifices 94C. The upstream section 96C of the third flowpath 92C may be at least partially (or completely) formed by an (e.g., annular) upstream third conduit 100C. The downstream section 98C of the third flowpath 92C may be at least partially (or completely) formed by a (e.g., annular) downstream third conduit 102C, where the third conduits 100C and 102C may be integral segments of a common, unitary conduit or may be separate fluidly coupled conduits. The upstream section 96C of the third flowpath 92C and its upstream third conduit 100C may extend circumferentially about (e.g., completely around) the upstream section 96A of the first flowpath 92A and its upstream first conduit 100A and/or the upstream section 96B of the second flowpath 92B and its upstream second conduit 100B. The downstream section 98C of the third flowpath 92C and its downstream third conduit 102C may extend circumferentially about (e.g., completely around) the downstream section 98A of the first flowpath 92A and its downstream first conduit 102A and/or downstream section 98B of the second flowpath 92B and its downstream second conduit 102B. With such a configuration, at least a portion of the third flowpath 92C within the injector stem <NUM> and/or within the injector nozzle <NUM> may be annular.

The third outlet orifices 94C are disposed at (e.g., on, adjacent or proximate) the nozzle tip <NUM>. Each of the third outlet orifices 94C of <FIG>, for example, is recessed slightly radially inward (relative to the nozzle axis <NUM>) from the outer surface <NUM> of the nozzle tip <NUM>. Referring to <FIG>, the third outlet orifices 94C are arranged circumferentially about the nozzle axis <NUM> and/or the first outlet orifice 94A in an annular third outlet orifice array. This third outlet orifice array and each of its third outlet orifices 94C are disposed radially outboard of the nozzle axis <NUM> and/or the first outlet orifice 94A by a radial distance <NUM> (relative to the nozzle axis <NUM>).

The third fuel circuit 90C of <FIG> is configured to direct the fuel received from the fuel source <NUM> out of the injector nozzle <NUM> through each third outlet orifice 94C (e.g., into the swirler bore <NUM> and/or into the combustion chamber <NUM>; see <FIG>) along a respective third trajectory 106C. This third trajectory 106C is angularly offset from the nozzle axis <NUM> and/or the first trajectory 106A by a third trajectory angle <NUM> (see <FIG>); e.g., an acute angle or a right angle. This third trajectory angle <NUM> may be between fifteen degrees (<NUM>°) and ninety degrees (<NUM>°); e.g., between fifteen degrees (<NUM>°) and thirty degrees (<NUM>°), between thirty degrees (<NUM>°) and forty-five degrees (<NUM>°), between forty-five degrees (<NUM>°) and sixty degrees (<NUM>°), etc. Changes to the third fuel circuit angle can be made to maximize fuel/air mixing at max power to control both NOx and smoke emissions while the first and second fuel circuits angles may be optimized for low power. In this way, fuel/air mixing is optimized over the entire power range. The third trajectory 106C may be selected to facilitate delivery of the fuel into a third (e.g., recirculation) zone within the combustion chamber <NUM> for combustion. The third trajectory 106C, a spray pattern of the fuel out of each third outlet orifice 94C, a flowrate of the fuel through each third outlet orifice 94C as well as various other parameters of the third fuel circuit 90C may be tailored for operation of the gas turbine engine <NUM> at high power settings to control both emissions and combustor tones. The third fuel circuit 90C, for example, may be sized and shaped at each third outlet orifice 94C to facilitate relatively high fuel atomization at a relatively high fuel flow rate and/or with a relatively high airflow rate through the swirler <NUM>.

The fuel source <NUM> includes a fuel reservoir <NUM> and a fuel flow regulator <NUM>. The fuel reservoir <NUM> is configured to contain the fuel before, during and/or after operation of the gas turbine engine <NUM>. The fuel reservoir <NUM> may be configured as or otherwise include a tank, a bladder and/or a cylinder. The flow regulator <NUM> is configured to direct the fuel from the fuel reservoir <NUM> to the one or more fuel injector assemblies <NUM> and, more particularly, to the one or more fuel injectors <NUM>. The flow regulator <NUM> may include one or more fuel pumps, one or more valves and/or one or more other devices for facilitating metered flow of the fuel from the fuel reservoir <NUM> to the fuel injectors <NUM> and selectively to the fuel circuits 90A, 90B and 90C.

Referring to <FIG> and <FIG>, the fuel system <NUM> is configured to deliver the fuel from the fuel source <NUM> through the fuel injectors <NUM> to the combustor <NUM> for combustion within the combustion chamber <NUM>. At each (or at least one or some) of the fuel injectors <NUM>, the first fuel circuit 90A provides (e.g., flows, delivers, directs, etc.) a first percentage of the fuel from the respective fuel injector <NUM> to the combustor <NUM>. The second fuel circuit 90B provides a second percentage of the fuel from the respective fuel injector <NUM> to the combustor <NUM>. The third fuel circuit 90C provides a third percentage of the fuel from the respective fuel injector <NUM> to the combustor <NUM>. These first, second and third percentages may vary during operation of the gas turbine engine <NUM> in order to improve one or more select parameters (e.g., lean blow out, atomization, etc.) at low power while improving one or more select other parameters (e.g., reduction in NOx, reduction in nvPM (particulate matter standard), etc.) at high power. The fuel system <NUM> may thereby optimize combustion performance across various power settings by varying the percentages (relative proportions) of the fuel delivered by the fuel circuits <NUM>. In addition to varying the percentages (relative proportions) of the fuel delivered by the fuel circuits <NUM>, each of the fuel circuits <NUM> may be tailored for one or more select power settings; e.g., designed for increased fuel atomization, fuel placement, etc. For example, the first fuel circuit 90A may be tailored for low power settings. The second fuel circuit 90B may be tailored for intermediate power settings. The third fuel circuit 90C may be tailored for high power settings.

<FIG> graphically illustrates how the ratios between the first, the second and the thirds percentages may change at various engine power settings. For example, the first percentage and/or the second percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times) the third percentage at an engine idle setting; here, the third percentage may be close to or may be a zero percentage. The second percentage may also be greater than (e.g., <NUM> times, <NUM> times) the first percentage at the engine idle setting. The second percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times, <NUM> times) the first percentage and/or the second percentage at an engine approach setting. The first percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times) the third percentage at the engine approach setting; here, the third percentage may be close to or may be a zero percentage. The second percentage may be equal to, or within a percentage (e.g., +/-<NUM>%, <NUM>%, <NUM>%, <NUM>%) of the third percentage at an engine cruise setting. The second percentage and/or the third percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times) the first percentage at the engine cruise setting; here, the first percentage may be close to or may be a zero percentage. The third percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times, <NUM> times) the first percentage and/or the second percentage at an engine climb setting. The second percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times) the first percentage at the engine climb setting; here, the first percentage may be close to or may be a zero percentage. The third percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times, <NUM> times) the first percentage and/or the second percentage at an engine max power setting. The second percentage may be greater than (e.g., <NUM> times, <NUM> times, <NUM> times) the first percentage at the engine max power setting; here, the first percentage may be close to or may be a zero percentage. The present disclosure, however, is not limited to the foregoing exemplary relationships between the first, the second and the third percentages.

In some embodiments, referring to <FIG>, the injector nozzle <NUM> may be configured such that the second trajectory angle <NUM> associated with each (or at least one) second outlet orifice 94B is equal to the third trajectory angle <NUM> associated with each (or at least one) third outlet orifice 94C. In other embodiments, referring to <FIG>, the injector nozzle <NUM> may be configured such that the second trajectory angle <NUM> associated with each (or at least one) second outlet orifice 94B is different than the third trajectory angle <NUM> associated with each (or at least one) third outlet orifice 94C. The second trajectory angle <NUM> of <FIG>, for example, is less than the third trajectory angle <NUM> to promote, for example, additional downstream travel of the fuel directed out from the respective second outlet orifice 94B. The second trajectory angle <NUM> of <FIG>, on the other hand, is greater than the third trajectory angle <NUM> to promote, for example, additional interaction with air traveling along the injector nozzle <NUM> through the swirler <NUM> (see <FIG>).

In some embodiments, referring to <FIG>, each (or at least one) second outlet orifice 94B may be circumferentially offset from (e.g., and circumferentially spaced from) each of the third outlet orifices 94C. Each second outlet orifice 94B of <FIG>, for example, is circumferentially centered between a respective circumferentially neighboring (e.g., adjacent) pair of the third outlet orifices 94C. Each (or at least one) second outlet orifice 94B, however, may alternatively be disposed circumferentially closer to one of the circumferentially neighboring pair of the third outlet orifices 94C than the other; e.g., asymmetrically aligned between the circumferentially neighboring pair of the third outlet orifices 94C. In other embodiments, referring to <FIG>, each (or at least one) second outlet orifice 94B may be circumferentially aligned with and/or circumferentially overlap a respective one of the third outlet orifices 94C.

In some embodiments, referring to <FIG>, the second outlet orifice array may be radially aligned with the third outlet orifice array. The radial distance <NUM> to each (or at least one) second outlet orifice 94B, for example, may be equal to the radial distance <NUM> to each (or at least one) third outlet orifice 94C. In other embodiments, referring to <FIG>, the third outlet orifice array may be radially offset from the second outlet orifice array. The radial distance <NUM> to each (or at least one) second outlet orifice 94B, for example, may be less than the radial distance <NUM> to each (or at least one) third outlet orifice 94C. With this arrangement of <FIG>, the third outlet orifice array is disposed radially outboard of the second outlet orifice array.

Referring to <FIG>, each fuel circuit <NUM> includes a fuel circuit passage <NUM> associated with each outlet orifice 94A, 94B, 94C (generally referred to as "<NUM>"). This fuel circuit passage <NUM> extends longitudinally along a longitudinal centerline <NUM> of that fuel circuit passage <NUM>, for example, from the downstream conduit 102A, 102B, 102C (generally referred to as "<NUM>") to the respective outlet orifice <NUM>. The outlet orifice <NUM> may thereby be formed at and/or by a downstream end of the respective fuel circuit passage <NUM>. At least a portion of the fuel circuit passage <NUM> / the passage centerline <NUM> at the passage downstream end may be straight. The fuel circuit passage <NUM> has a lateral size <NUM> (e.g., a diameter) measured across the fuel circuit passage <NUM> (e.g., perpendicular to the passage centerline <NUM>) between (e.g., diametrically) opposing sides of the fuel circuit passage <NUM>. In some embodiments, referring to <FIG>, the passage size <NUM> may be uniform (e.g., constant) as at least a portion or an entirety of the fuel circuit passage <NUM> extends longitudinally along the passage centerline <NUM> towards (e.g., to) the respective outlet orifice <NUM>. In other embodiments, referring to <FIG>, the passage size <NUM> may change (e.g., decrease, increase, vary down and up, etc.) as at least a portion or an entirety of the fuel circuit passage <NUM> extends longitudinally along the passage centerline <NUM> towards (e.g., to) the respective outlet orifice <NUM>.

Referring to <FIG>, the passage size <NUM> may decrease along an upstream portion <NUM> of the fuel circuit passage <NUM>, while the passage size <NUM> may remain uniform along a downstream portion <NUM> of the fuel circuit passage <NUM> which extends longitudinally between the upstream portion <NUM> and the respective outlet orifice <NUM>. The fuel circuit passage <NUM> may thereby be configured as a convergent passage. More particularly, the fuel circuit passage <NUM> of <FIG> converges inward towards the passage centerline <NUM> as that fuel circuit passage <NUM> extends longitudinally towards the respective outlet orifice <NUM>.

Referring to <FIG>, the fuel circuit passage <NUM> may include an upstream portion <NUM>, a downstream portion <NUM> and an intermediate portion <NUM> extending longitudinally from the upstream portion <NUM> to the downstream portion <NUM>, where the downstream portion <NUM> extends longitudinally towards (e.g., to) the respective outlet orifice <NUM>. The passage size <NUM> may decrease as the upstream portion <NUM> extends longitudinally towards (e.g., to) the intermediate portion <NUM>. The passage size <NUM> may remain uniform along the intermediate portion <NUM> between the upstream portion <NUM> and the downstream portion <NUM>. The passage size <NUM> may increase as the downstream portion <NUM> extends longitudinally from the intermediate portion <NUM> towards (e.g., to) the respective outlet orifice <NUM>. The fuel circuit passage <NUM> may thereby be configured as a convergent-divergent passage.

In some embodiments, each of the fuel circuits <NUM> may be provided with common fuel circuit passage configurations; e.g., the configuration of <FIG>. In other embodiments, any two of the fuel circuits <NUM> may be provided with common fuel circuit passage configurations while the other fuel circuit <NUM> is provided with another fuel circuit configuration. In still other embodiments, each fuel circuit <NUM> may be provided with a discrete fuel circuit passage configuration.

In some embodiments, referring to <FIG>, each (or at least one) outlet orifice <NUM> of any one, some or all of the fuel circuits <NUM> may have a circular cross-sectional geometry. In other embodiments, referring to <FIG>, each (or at least one) outlet orifice <NUM> of any one, some or all of the fuel circuits <NUM> may have a (e.g., radially, lengthwise) elongated cross-sectional geometry. The outlet orifice <NUM> of <FIG>, for example, has an oval cross-sectional geometry where, for example, the respective fuel circuit passage <NUM> of <FIG> has a circular cross-sectional geometry and that fuel circuit passage <NUM> extends to a surface (e.g., <NUM>, <NUM>) of the injector nozzle <NUM> at an angle; e.g., an acute angle. In still other embodiments, referring to <FIG>, each (or at least one) outlet orifice <NUM> of any one, some or all of the fuel circuits <NUM> may have a (e.g., tangentially, widthwise) elongated cross-sectional geometry. The respective fuel circuit passage <NUM> of <FIG>, for example, is configured to provide a flat fan nozzle outlet; e.g., flat fan tip, a cat's eye tip, etc..

In some embodiments, each of the fuel circuits <NUM> may be provided with common outlet orifice configurations; e.g., the configuration of <FIG> or <FIG>. In other embodiments, any two of the fuel circuits <NUM> may be provided with common outlet orifice configurations while the other fuel circuit is provided with another outlet orifice configuration. In still other embodiments, each fuel circuit <NUM> may be provided with a discrete outlet orifice configuration.

In some embodiment, referring to <FIG>, each (or at least one) fuel circuit trajectory 106A, 106B, 106C may lay in a reference plane (e.g., <NUM>) that includes the nozzle axis <NUM>. In other embodiments, referring to <FIG>, each (or at least one) fuel circuit trajectory <NUM> (e.g., 106B, 106C) may be skewed (e.g., angularly offset) from and/or laterally offset from the reference plane <NUM> that includes the nozzle axis <NUM>. With such an arrangement, the fuel circuit <NUM> may facilitate fuel swirl out of the injector nozzle <NUM>.

In some embodiments, each of the fuel circuits <NUM> may be configured for common trajectory orientations; e.g., the orientation of <FIG>. In other embodiments, the fuel circuits <NUM> (e.g., 90B and 90C) may be configured for discrete trajectory orientations. For example, the second fuel circuit 90B may be configured for the trajectory orientation of <FIG> and the third fuel circuit 90C may be configured for the trajectory orientation of <FIG>. In another example, both the second fuel circuit 90B and the third fuel circuit 90C may be configured for the trajectory orientations of <FIG>; however, a degree of trajectory skew from the reference plane may be different and/or in an opposing direction.

The fuel system <NUM> and its fuel injector(s) <NUM> may be included in various gas turbine engines other than the one described above. The fuel system <NUM> and its fuel injector(s) <NUM>, for example, may be included in a geared gas turbine engine where a geartrain connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the fuel system <NUM> and its fuel injector(s) <NUM> may be included in a gas turbine engine configured without a geartrain; e.g., a direct drive gas turbine engine. The fuel system <NUM> and its fuel injector(s) <NUM> may be included in a geared or non-geared gas turbine engine configured with a single spool, with two spools (e.g., see <FIG>), or with more than two spools. The gas turbine engine may be configured as a turbofan engine, a turbojet engine, a turboprop engine, a turboshaft engine, a propfan engine, a pusher fan engine or any other type of gas turbine engine for an aircraft propulsion system. The gas turbine engine may alternatively be configured as an auxiliary power unit (APU) or an industrial gas turbine engine. The present disclosure therefore is not limited to any particular types or configurations of gas turbine engines.

Claim 1:
An assembly (<NUM>) for a gas turbine engine (<NUM>), comprising:
a fuel injector (<NUM>) including a nozzle (<NUM>);
the nozzle (<NUM>) extending axially along an axis (<NUM>) to a nozzle tip (<NUM>);
wherein
the fuel injector (<NUM>) includes a plurality of discrete fuel circuits (<NUM>) including a first fuel circuit (90A), a second fuel circuit (90B) and a third fuel circuit (90C);
the first fuel circuit (90A) comprising a first fuel outlet (94A) disposed at the nozzle tip (<NUM>);
characterized in that
the second fuel circuit (90B) comprising a plurality of second fuel outlets (94B) arranged circumferentially about the axis (<NUM>) at the nozzle tip (<NUM>) in a second fuel outlet array; and
the third fuel circuit (90C) comprising a plurality of third fuel outlets (94C) arranged circumferentially about the axis (<NUM>) at the nozzle tip (<NUM>) in a third fuel outlet array.