Effusion Cooled Fuel Nozzle Tip

The present disclosure relates to combustion systems, and more particularly, to features for cooling fuel injectors of combustion systems.

Fuel injectors deliver fuel and oxidant flows into a combustion chamber for combustion. Portions of fuel injectors exposed to high temperatures from combustion experience high heat flux, increased thermal stress, and increased coking risk to internal fuel passages. Heat shields are used to thermally protect fuel injectors, which are considered satisfactory for their intended purpose. However, portions of the fuel injector nozzle remain unprotected. Additional features for protecting fuel injectors from high-temperature exposure are needed.

A fuel injector according to an example of this disclosure includes a nozzle and a cap configured to deliver an oxidant-fuel mixture along a nozzle axis. The nozzle includes a fuel passage and a swirler. The fuel passage extends along the nozzle axis. The swirler circumscribes the fuel passage and includes multiple oxidant passages that converge towards the nozzle axis. The cap surrounds at least a portion of the nozzle and includes a peripheral body, an end body, and an effusion passage. The peripheral body circumscribes the swirler. The end body joins with the peripheral body and extends radially towards the nozzle axis. The effusion passage extends through the cap to intersect at least one of the peripheral body and the end body from an inlet to an outlet. The outlet is radially outward from the oxidant passages relative to the nozzle axis.

is a cross-sectional view of injectorthat can include one or more effusion passages for cooling exterior surfaces of injectordirectly exposed to high-temperature combustion. Effusion passages divert oxidant flow across exposed surfaces of injectorand thereby provide thermal protection. For example, effusion passages can direct oxidant flow across the end face of injector.

While a particular injectoris depicted by, it shall be understood that effusion passages, as described below, can be incorporated into other examples of injector, or other components exposed to high temperature gas or fluid. Injectorcan include a single fuel path and/or a single air path in some examples. Other examples of injectorcan include multiple fuel paths connected to a single fuel source, or multiple fuel passages connected to multiple fuel sources. Fuel sources can include carbon-based fuel, other liquid or gaseous fuel, and/or multi-phase fuel (e.g., fuel with liquid and gaseous phases). In some examples, injectorcan receive a carbon-based liquid fuel and a multi-phase fuel (e.g., liquid hydrogen). Injectorcan include additional air paths directed towards and/or between two or more fuel paths.

Injectoris a fuel delivery device installed within a combustor of a gas turbine engine. In operation, injectordelivers fuel and oxidant (e.g., air) at specified mass flow rates to provide an oxidant-fuel mixture within the combustor combustion chamber. As depicted, injectorincludes heat shield, mount, stem, nozzle, and manifold. Heat shield, mount, stem, nozzle, and manifoldcan be an assembly of components joined at respective interfaces to form injector. In some examples, components of injectorare joined using a brazing process and/or a welding process. In other examples, heat shield, mount, stem, nozzle, and manifolddescribe regions of a monolithic body formed by, for example, an additive manufacturing process. Further, certain features of injectorcan be formed by a machining process or other subtractive manufacturing.

Mountsupports injectorfrom stationary structureof the gas turbine engine. One or more flanges, lips, and/or pilot diameters allow mountto interface with stationary structure. Mountfurther includes one or more fasteners, keys, and/or pins for affixing injectorrelative to stationary structureand the combustor of gas turbine engine. As depicted, mountis a flange that abuts stationary structure, which can be a casing of gas turbine engine that surrounds the combustor. Mountfurther includes a pilot diameter received within an opening of stationary structureand may include fasteners (not shown) for affixing mountto stationary structure.

Manifoldis outboard of mountand includes supply lines fluidly communicating with a fuel source and/or one or more other adjacent injectors. Manifold can include one or more pipes, conduits, hoses, and/or internal passages to define supply lines, which communicate with one or more fuel passages of stem.

Stemextends longitudinally from mountthrough stationary structureinto combustion chamber of the combustor. Stemincludes one or more fuel passages in fluid communication with one or more supply passages of manifold. Stemcan extend linearly from mountsuch that stemis devoid of bends or elbows. In other examples, stemcan include one or more linear sections connected by respective bends such that a longitudinal axis of stemrepresented by dashed line L changes at each bend relative to an adjacent linear section of stem. As depicted, stemextends radially inward from mountrelative to an axis of gas turbine engine. Stemincludes a bend spaced apart from mount and extends at an angle relative to the radial section of stemto nozzle.

Nozzleis disposed at a distal end of stemwithin the combustion chamber and extends along nozzle axis A parallel to a distal portion of stem. Nozzleincludes a center body and one or more annular bodies concentrically disposed with respect to the center body to form one or more discharge fuel passages configured to direct fuel along nozzle axis A. Each of the one or more discharge fuel passages fluidly connects to at least one of the fuel passages of the stemto define respective fuel paths between manifoldand nozzle. Further, the annular bodies of nozzleform at least one gaseous passage for directing oxidant through nozzleto mix with fuel discharged through fuel paths of injector.

Swirleris an annular body surrounding nozzleand circumscribing the one or more fuel passages extending through nozzle. Swirlerincludes one or more oxidant passages that directs an oxidant flow towards fuel discharged from nozzleand thereby produces a target oxidant-fuel mixture. In some examples, oxidant passages can converge towards nozzle axis A to encourage oxidant-fuel mixing.

Capsurrounds at least a portion of nozzleand swirler, extending from the discharge end of nozzletowards heat shieldand stem. The radially interior periphery of capdefines a bore communicating with discharge ends of nozzleand swirler. Capincludes one or more effusion passages that direct oxidant flow from one or more oxidant passages across an exterior end face of cap.

In operation, fuel injectordelivers fuel and oxidant within predetermined oxidant-fuel ratio range associated with one or more operating conditions of a gas turbine engine. Ignition of the oxidant-fuel mixture within combustion chamber produces high temperatures over 1,600 degrees Celsius. The high-temperature and pressure environment within combustion chamber exposes portions of nozzle, swirler, and capto high thermal stress and increasing coking potential of fuel within fuel discharge passages within nozzle, particularly portions of fuel discharge passages adjacent to exposed surfaces of injector.

is an end view of captaken along line B-B in.is a simplified cross-sectional view along line D-D in.anddepict a schematic representation of effusion passagesA-M along with oxidant passagesA-N. Portions of nozzleand swirlerare shown along with cap. Swirlerandare discussed together.

Swirlerincludes a circumferential array of guides, vanes, and/or internal passages that define oxidant passagesA-N, which are formed by circumferentially adjacent guides, vanes, and/or internal passages. Swirlerincludes at least one oxidant passageA and up to oxidant passageN in which “N” denotes an arbitrary number of oxidant passagesA-N. Oxidant passagesA-N extend from oxidant plenumto an outlet end of nozzle. A radially outer exterior of oxidant passagesA-N can be open to capin some examples. Oxidant passagesA-N have a radially converging orientation such that each oxidant passagesA-N direct oxidant flows towards nozzle axis A to mix with and/or atomize fuel discharged via nozzle. That is, oxidant passagesA-N permit oxidant to flow towards outlet end of nozzlein operation. Oxidant passagesA-N may additionally include a circumferential orientation such that oxidant flows exit swirler with a circumferential velocity component about nozzle axis A (i.e., swirl).

Capincludes peripheral body, end body, and at least one effusion passageA and up to effusion passageM, in which “M” denotes a maximum number of effusion passagesA-M. Peripheral bodyis an annular section of capthat circumscribes an outer periphery of swirler. Outer peripheral surfaceA delimits a radial outer surface of peripheral bodyand inner peripheral surfaceB delimits a radial inner surface of peripheral body. Inner peripheral surfaceB can form a radially outer boundary of oxidant passagesA-N in some examples. End bodyincludes and is delimited by exterior end surfaceA and interior end surfaceB. End bodyis joined with peripheral bodyand extends radially inward toward nozzle axis A.

Peripheral bodyand/or end bodyof capcan be spaced from swirler, or a portion thereof, to define oxidant plenum. Oxidant plenumcan be one or more cavities (e.g., an annular cavity) communicating with a suitable source of oxidant. In some examples, oxidant can be fed through oxidant passages (not shown) within stemto one or more oxidant passagesA-N. In other examples, oxidant is supplied from combustor (e.g., a region between outer combustor wall and outer heat shield).

Exterior end surfaceA borders a combustion chamber and is exposed directly to the high-temperature combustion gas during operation of the combustor chamber. Interior end surfaceB faces inward towards nozzleand swirler. Interior end surfaceB may contact mating surfaces of nozzleand/or swirler. In some examples such as the exampled depicted by, interior end surfaceB borders oxidant passagesA-N. Exterior end surfaceA is depicted as a planar surface normal to nozzle axis A in. However, other surface profiles are contemplated herein for exterior end surfaceA. For instance, exterior end surfaceA can form a conical surface, a concave surface, and/or convex surface, or any combination thereof in some examples.

Effusion passagesA-M extend from inletsA-M to respective outletsA-M. OutletsA-M of effusion passagesA-M can intersect capradially outward from oxidant passages of swirlerand the fuel passage of nozzle. Effusion passagesA-M are sized to produce oxidant flow across an exterior surface of cap. In some examples, the length of each effusion passage, or a metering portion thereof, can be at least four times the hydraulic diameter. Effusion passagesA-M can include a circular, rectangular, elliptical, ovular, or oblong cross-sectional shape. For example, effusion passagesA-M can have a constant, circular cross-section with a diameter greater than or equal to 0.254 millimeters (i.e., 0.010 inches) and less than or equal to 0.762 millimeters (i.e., 0.030 inches). In other examples, effusion passagesA-M can include complex cross-sections formed by one or cross-sectional shapes. Effusion passagesA-M with complex cross-sections can include a metering section and/or a diffusion section. The metering section can include a constant cross-section with any of the foregoing cross-sectional shapes whereas the diffusion section can include one or more lobes, and/or walls that diverge towards respective outletsA-M.

Effusion passagesA-M divert a portion of oxidant flow across an exposed surface of cap. The percentage of oxidant flow diverted by effusion passagesA-M can be greater than or equal to one percent of all oxidant flow and less than or equal to ten percent of oxidant flow in some examples. In other examples, the percentage of oxidant flow diverted by effusion passagesA-M can be greater than or equal to one percent of all oxidant flow and less than or equal to five percent of oxidant flow.

Centerlines connecting geometric centers of inletsA-M to respective outletsA-M describe orientations of effusion passagesA-M. Effusion passagesA-M can radially diverge from nozzle axis A in a direction along centerlines from inletsA-M to respective outletsA-M. In this way, cooling provided by oxidant flows through effusion passagesA-M do not significantly impede or disrupt mixing and/or atomization of fuel discharged by nozzle. In other examples, some or all of effusion passagesA-M have a circumferential orientation in a direction along centerlines from inletsA-M to respective outletsA-M. The circumferential orientation of effusion passagesA-M can define a clockwise orientation, or a counterclockwise orientation as viewed in, which can be the same or counter to a circumferential orientation of oxidant passagesA-N. Examples of effusion passagesA-M with the same circumferential orientation as swirlerbenefit from reduced shear between oxidant flow exiting effusion passagesA-M and oxidant flow exiting swirler.

The circumferential orientation and/or planar orientation of effusion passagesA-M can be described circumferential angles and planar angles. The circumferential angle of each effusion passage can be described by the angle between the effusion passage centerline and a radial line extending from nozzle axis A to intersect the centerline at the effusion passage outlet. The circumferential angles of respective effusion passagesA-M can be less than or equal to eighty degrees and greater than or equal to sixty degrees, in some examples. The planar angle of respective effusion passagesA-M can be described by the angle between the effusion passage centerline and exterior end surfaceA of cap. Planar angles can be greater than zero degrees and less than or equal to thirty degrees, for example.

While capcan include a single effusion passageA, examples of capwith multiple effusion passagesA-M include up to a maximum number “M” of effusion passagesA-M based on a number “N” of oxidant passagesA-N. In some examples, the maximum number “M” of effusion passagesA-M can be equal to two times a number “N” of oxidant passagesA-N. Further, each of oxidant passagesA-N can fluidly communicates with no more than two effusion passages in certain examples. In other examples, at least some oxidant passagesA-N fluidly communicate with less than two effusion passages, or do not fluidly communicate with any effusion passagesA-M. Distributing outletsA-M among oxidant passagesA-N in this manner limits or avoids substantial disruptions to oxidant-fuel mixing of injector.

OutletsA-M of effusion passagesA-M can be distributed equally about nozzle axis A. In other examples, outletsA-M can have unequal circumferential spacing about nozzle axis A. Exterior end surfaceA of capcan be partitioned into two or more equal sectors. In some examples, circumferential spacing of effusion passage outletsA-M is less within a target sector relative to circumferential spacing of effusion passage outletsA-M, if any, in one or more other sectors. In each sector, the number of effusion passage outlets within each sector does not exceed a total number “M” of effusion passage outlets divided by the number of sectors. In this way, a density of effusion cooling flow can be localized within the target sector in order to counteract local heat flux maximums imposed on end bodyof capwithout significantly disrupting oxidant flow discharged through swirler.

Additionally, outletsA-M of effusion passagesA-M can be arranged along a common radius, or at multiple radii relative to nozzle axis A. In each instance, outletsA-M are radially outward from an outlet of swirler. Effusion passagesA-M with outletsA-M arranged at multiple radii can include, for example, a radially staggered arrangement in which a first subset of outletsA-M are radially outward from a second subset of outletsA-M. In a further example, each outlet of the first subset can be circumferentially interposed between two adjacent outlets of the second subset to create staggered sets of effusion outlets.

Locations of inletsA-M and outletsA-M are selected to prevent reverse flow through effusion passagesA-M. Reverse flow occurs when flow occurs in a reverse direction from outletsA-M to inletsA-M of effusion passagesA-M. InletsA-M of effusion passagesA-M can be located where static pressures local to each of inletsA-M exceeds static pressures local to respective outletsA-M through the entire operational range of injectorby a margin sufficient to achieve a target oxidant flow in a forward direction from inletsA-M to outletsA-M. Ensuring forward flow through effusion passagesA-M prevents ingestion of high temperature fluids and thereby increasing the temperature of injector, and more particularly increasing the temperature of cap.

As depicted inand, inletsA-M are disposed along interior end surfaceB in fluid communication with one of oxidant passagesA-N, and outletsA-M are disposed along exterior end surfaceA of cap. InletsA-M of the depicted effusion passagesA-M fluidly communicate with one of oxidant passagesA-N, and direct a portion of oxidant flow within oxidant passagesA-N across exterior end surfaceA of cap.

is an end view of captaken along line B-B indepicting an alternative arrangement of effusion passagesA-M.is a simplified cross-sectional view along line E-E in.anddepict another schematic representation of effusion passagesA-M along with oxidant passagesA-N. Effusion passagesA-M can have a circumferential orientation and planar orientation characterized by radial angles and planar angles, respectively, as described above. As depicted in, and, however, inletsA-M of effusion passagesA-M are disposed along outer peripheral surfaceA of capin lieu of interior end surfaceB. Accordingly, effusion passagesA-M, as depicted inand, fluidly communicate with oxidant plenum, or a region exterior to injector.

Fuel Injector with Effusion Passages

The following are non-exclusive descriptions of possible embodiments of the present invention.

A fuel injector configured to deliver an oxidant-fuel mixture along a nozzle axis includes, among other possible things, a nozzle and a cap. The nozzle includes a fuel passage and a swirler. The fuel passage extends along the nozzle axis. The swirler circumscribes the fuel passage and includes a plurality of oxidant passages that converge towards the nozzle axis. The cap includes a peripheral body, an end body, and an effusion passage. The peripheral body circumscribes the swirler. The end body joins to the peripheral body and extends radially towards the nozzle axis. The effusion passage extends through the cap to intersect at least one of the peripheral body and the end body from an inlet to an outlet. The outlet is radially outward from the plurality of oxidant passages relative to the nozzle axis.

The fuel injector of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components.

A further embodiment of the foregoing fuel injector, wherein the effusion passage can extend along a passage centerline from the inlet to the outlet that diverges radially from the axis.

A further embodiment of any of the foregoing fuel injectors, wherein the inlet of the effusion passage can fluidly communicate with a first oxidant passage of the plurality of oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein the plurality of oxidant passages can fluidly communicate with a region exterior to the nozzle.

A further embodiment of any of the foregoing fuel injectors, wherein the inlet of the effusion passage can intersect the peripheral body and can fluidly communicate with the region.

A further embodiment of any of the foregoing fuel injectors, wherein the effusion passage can form a circumferential angle with respect to a radial line extending from the axis.

A further embodiment of any of the foregoing fuel injectors, wherein the effusion passage can form a planar angle with respect to the end body.

A further embodiment of any of the foregoing fuel injectors, wherein the circumferential angle can be greater than or equal to sixty degrees and less than or equal to eighty degrees.

A further embodiment of any of the foregoing fuel injectors, wherein the planar angle can be greater than zero degrees and less than or equal to thirty degrees.

A further embodiment of any of the foregoing fuel injectors, wherein circumferential orientations of the plurality of effusion passages and the swirler can be the same.

A further embodiment of any of the foregoing fuel injectors, wherein circumferential orientations of the plurality of effusion passages and the swirler can be different.

A further embodiment of any of the foregoing fuel injectors, wherein respective outlets of the plurality of effusion passages can be equally spaced about the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein respective outlets of the plurality of effusion passages can be asymmetrically spaced about the nozzle axis.

A further embodiment of any of the foregoing fuel injectors, wherein the cap includes a plurality of effusion passages.

A further embodiment of any of the foregoing fuel injectors, wherein a maximum number of effusion passages is equal to or less than two times a number of oxidant passages.

A further embodiment of any of the foregoing fuel injectors, wherein the exterior peripheral surface of the cap can be divided into a discrete number of sectors.

A further embodiment of any of the foregoing fuel injectors, wherein a number of effusion passages within a sector does not exceed an equal portion of the maximum number of effusion passages per sector.

A further embodiment of any of the foregoing fuel injectors, wherein less than or equal to twenty five percent of respective outlets can be disposed within each of four equal sectors of the end face.

A further embodiment of any of the foregoing fuel injectors, wherein respective inlets of the plurality of effusion passages can fluidly communicate with one of the oxidant passages.