Patent ID: 12196421

DETAILED DESCRIPTION

Turning now to the drawings in greater detail and initially toFIG.1, a combustor of a gas turbine engine according to aspects of the disclosure is designated generally by the numeral100. The combustor100generally includes a first, or radially outward, injector102, a second, or radially inward, injector104, a generally cylindrical flow sleeve106, and a generally cylindrical combustion liner108that is positioned radially inward from the flow sleeve106and generally defines a combustion zone110. The first injector102is generally annularly shaped and surrounds the combustion liner108and is positioned at a downstream end of the flow sleeve106. The second injector104is positioned radially inward of the combustion liner108at an inlet end of the combustion zone110.

As best understood with reference toFIG.2, during use of the combustor100compressed air is presented to both the first and second injectors102,104, where it mixes with a fuel source and then is ignited, supporting a flame within the combustion chamber110. Compressed air following a radially outer path112along a radially outer surface of the flow sleeve106passes through radially outward vanes and/or openings provided in the first injector102without being mixed with fuel therein, instead continuing downstream to a portion of the combustor100where the air turns and passes through the second injector104. Here, the compressed air mixes with a fuel source and is ignited to support a flame near a central axis of the combustor100. Compressed air following a radially inner path114between the flow sleeve106and the combustion liner108passes through different (i.e., radially inward) vanes and/or openings provided in the first injector102, where it is mixed with a fuel source. The fuel/air mixture then travels to a dome plate130or similar structure where it turns substantially 180 degrees, entering the combustion chamber110where it is ignited to support a flame radially outward of the flame supported by the second injector104. In some embodiments, the first injector102is referred to as the “main” injector, while the second injector104is referred to as the “pilot” injector.

FIGS.3A-3Bshow portions of one embodiment of the first, or main, injector102used to mix fuel and air passing through the radially inner path114. In this embodiment, the first injector102includes a plurality of radially outward first vanes116radially arrayed about a central axis of the combustor100, with neighboring ones of the plurality of first vanes116defining a plurality of first passages118therebetween. As seen inFIG.3A, the first vanes116and passages118do not include any fuel injection openings or similar structures therein, and thus the compressed air in the radially outer path112passes through the openings118without mixing with any fuel and continues downstream to the second injector104.

However, the first injector102also includes a plurality of second vanes120radially inward of the plurality of first vanes116and similarly radially arrayed about a central axis of the combustor100. Neighboring ones of the plurality of second vanes120define a plurality of second passages122therebetween, through which compressed air traveling along the radially inner path114passes. Each of the vanes120generally includes a planar leading edge (not shown) and a planar trailing edge128, with the planar leading edge and the planar trailing edge128extending substantially perpendicular, or cross-streamwise, to a direction of airflow within the injector102. Moreover, each of the vanes120includes a plurality of fuel injection holes126provided at the trailing edge128(in this instance, in the planar face located at the trailing edge128), which are in fluid communication with a plurality of fuel feed holes124. Fuel from a manifold or similar structure (not shown) is fed to the compressed air passing along the radially inner path114via the fuel feed holes124and the fuel injection holes126. More particularly, as the compressed air passes through the second passages122and over the vanes120, the air is mixed with fuel exiting the fuel injection holes126proximate the trailing edge128of each vane120. The fuel/air mixture thereafter continues along the radially inner path114to the dome plate130(FIG.2) or similar structure that is positioned at an inlet end of the combustion zone110. The dome plate130reverses the direction of flow of the fuel/air mixture and delivers it into an inlet end of the combustion zone100for ignition.

In this embodiment, the planar face of the trailing edge128of each vane120provides a surface on which a flame may anchor during operation of the combustor100. Flames anchored at this portion of the radially inner path114may be undesirable because the anchored flames may lead to premature ignition of the fuel/air mixture, damage to the first fuel injector102or other components, or other undesirable drawbacks. Thus, according to some embodiments of the technology described hereafter, the leading or trailing edge of the vanes of the first injector102include an irregular or non-planar profile reducing the surfaces which may lead to flame anchoring while improving mixture of the fuel and air along the radially outer and/or inner paths112,114, thereby resulting in a more efficient burning and reduced emissions, among other benefits.

FIG.4shows one embodiment of an improved first injector202according to aspects of the disclosure. In this embodiment, the first (or, alternatively, main) injector202is generally annularly shaped and includes a radial array of first vanes216radially outward of a radial array of second vanes220. Neighboring ones of the plurality of first vanes216define a plurality of first passages218, while neighboring ones of the plurality of second vanes220define a plurality of second passages222. Again, as discussed with the embodiment of the first injector102shown inFIGS.3A-3C, when installed and used in a combustor100, compressed air passing to the second injector104along the radially outer path112will pass through the plurality of first openings218and over the plurality of first vanes220without mixing with fuel and continue downstream to the second injector104, while compressed air passing along the radially inner path114will pass through the plurality of second passages222, through the second passages122and over the plurality of second vanes220, and mix with fuel. In that regard, the first injector202includes a plurality of fuel feed holes224, each in communication with a plurality of fuel injection holes226provided on a trailing edge228of each second vane220or nearer the trailing edge228than a leading edge230(FIG.5C).

As best seen inFIGS.5A-5C, which show close-up portions of the first injector202, the trailing edge228of each radially inner vane220includes a stepped profile. More particularly, the trailing edge228in this embodiment includes three distinct portions,228a,228b, and228c. The radially outer first portion228aand the radially inner third portion228cof the trailing edge228are circumferentially offset from the intermediately positioned second portion228b. In this embodiment, each vane220includes two fuel injection holes226, which are provided on the second portion228bof the trailing edge228. However, in other embodiments the vanes220may include more or less fuel injection holes226and/or one or more of the fuel injection holes226may be located elsewhere (i.e., on one of the first or third portions228a,228cof the trailing edge228) without departing from the scope of the disclosure. Moreover, in this embodiment the radially inner fuel injection hole226is bigger (i.e., has a larger diameter) than the radially outer fuel injection hole226. For example, in one non-limiting example the inner fuel injection hole226has a diameter of approximately 0.112 inches, while the outer fuel injection hole226has a diameter of approximately 0.059 inches. In other embodiments, the fuel injection holes226may be the same size, the radially outer fuel injection hole226may be bigger than the radially inner fuel injection hole226, and/or the fuel injection holes226may be differently shaped or configured without departing from the scope of the disclosure.

The profile of the vanes220shown inFIGS.4and5A-C may exhibit mixing and flame-holding mitigation benefits as compared to, e.g., the embodiment of the first injector102shown inFIGS.3A-3C. Namely, the leading edge230(FIG.5C) of each vane220is rounded similar to a leading edge of an airfoil, providing enhanced flow and aerodynamic benefits; i.e., the rounded leading edge230reduces pressure loss of the compressed air flowing around the vanes220. The stepped profile of the trailing edge228increases mixing at the trailing edge228of the vane220because the irregular profile introduces turbulence, causing the compressed air passing over the trailing edge228to swirl and mix with fuel leaving the fuel injection holes226. In this regard, the fuel injection holes226are located and configured such that the fuel exiting therefrom is injected into and entrapped by the swirling compressed air of the vortices created by the stepped profile of the trailing edge228, enhancing mixing of the fuel with the compressed air.

Moreover, because there is no planar face provided substantially perpendicular to the compressed airflow at the trailing edge228(in contrast to the planar face provided at the trailing edge128of the vane120), there is beneficially no surface for a flame to anchor. Put another way, there are no aft-facing base areas of the vanes220, thereby reducing or eliminating flame-holding at the first injector202. Thus, the stepped profile of the trailing edge228of the vanes220reduces unwanted flame anchoring upstream from the combustion zone110.

In the depicted embodiment shown inFIGS.5A-C, the second portion228bof the trailing edge228is longer, in the radial direction, than the third portion228c, and the second portion228band third portion228care both longer than the first portion228a. In other embodiments, the vane220may be otherwise configured, such as, e.g., having two or more of the stepped portions228a,228b,228chaving the same length in the radial direction, or having one or both of the stepped portions228a,228cbeing longer than the stepped portion228bwithout departing from the scope of the disclosure. Moreover, in some embodiments the vanes220may include more or less stepped portions at the trailing edge228than is depicted inFIGS.4and5A-C without departing from the scope of the disclosure, such as, e.g., two stepped portions or four or more stepped portions. In such embodiments, distal ends of neighboring ones of the stepped portions will be spaced apart and alternate in the circumferential direction, similar to the configuration of stepped portions228aand228binFIGS.4and5A-C.

The trailing edge228of the plurality of second vanes220may be alternatively configured while providing similar benefits without departing from the scope of the disclosure, as are shown in the embodiments depicted inFIGS.6A-8C. In the embodiments shown inFIGS.6A-8C, the depicted vanes320,420,520form part of a first, or main, injector302,402,502, respectively, similar to the first injector202shown inFIG.4. In this regard, although not shown, the injectors302,402,502will include a second radial array of vanes radially outward of the depicted vanes320,420,520, which would be similarly configured to the vanes216shown inFIG.4and thus are not discussed again for convenience.

FIGS.6A-6Cshow vanes320of the first injector302that include a waved trailing edge328profile of the vanes320. The waved trailing edge328profile may generally follow the contour of a sinusoidal or similar wave, with one or more fuel injection holes326(in the depicted embodiment, two) provided along the wave.

The injector402shown inFIGS.7A-7Cincludes a trailing edge428profile of the vanes420that includes both a stepped portion and a wave-like portion radially inward of the stepped portion, although in other embodiments the trailing edge profile428could include a wave-like portion radially outward of the stepped portion instead of or in addition to the radially inward stepped portion. Moreover, in this embodiment the stepped portion includes three fuel injection holes426. The holes426may be of equal size or varying size. In the depicted embodiment, the two radially inward holes have an approximately equal cross-sectional area, while the radially outward fuel injection hole426is smaller. However, in other embodiments the holes426may be otherwise sized and configured without departing from the scope of the disclosure such as, e.g., a configuration in which the largest fuel injection hole426is provided at least at a radially outermost location.

FIGS.8A-8Cshow a trailing edge528profile of the vanes520in the first injector502that is wavy, but irregular. That is, the profile does not generally follow a sinusoidal or similar wave, but otherwise includes smooth arcs oscillating in the circumferential direction, with a pair of fuel injection holes526provided on the ridge of the wave. In some embodiments, the trailing edge528profile of this embodiment may be described as an angled sinusoidal wave, an irregular sinusoidal wave, a skewed sinusoidal wave, or similar. Again, more or less fuel injection holes526, and fuel injection holes526of varying diameters, can be implemented without departing from the scope of the disclosure.FIGS.8A-8Cdemonstrate that aspects of the disclosure include a wide array of trailing edge geometries, even irregular waves and similar, that provide the benefits of enhanced mixing at the trailing edge and mitigated flame anchoring, among others.

FIGS.9A-9Bshow another embodiment of a first injector602according to aspects of the disclosure. In this embodiment, the plurality of first vanes616are substantially elliptical in cross-section; that is, both the leading edges and trailing edges of the vanes616are rounded thereby providing a more streamlined flow and thus enhanced airflow properties such as reduced pressure drop, allowing the compressed air to freely flow along the radially outer flow path112to the second injector as best illustrated inFIG.10. The plurality of second vanes620in this embodiment are similar in configuration to the second vanes220shown inFIGS.4and5A-C, and thus will not be discussed again in detail. However, in this embodiment the circumferentially stepped portions of the trailing edge628include rounded or filleted transition edges632separating the stepped portions. These rounded or filleted transition edges632reduce thermal and other stresses at the transition between the circumferentially stepped portions, thereby improving the life of the injector602and the plurality of second vanes620thereof. Moreover, the rounded or filleted transition edges632improve aerodynamic mixing of the compressed air and fuel provided by the fuel injection holes, providing a more homogenous mixture to the combustion zone.

Again,FIG.10shows a partial cross-sectional view of a combustor100employing the first injector602, which demonstrates how the compressed air flows along the radially outer and inner flow paths112,114. Moreover, as seen inFIG.10, the improved mixing and similar benefits of the injectors described herein may permit inclusion of the injectors in a combustor100without the need for tear strips, seal lands, knurling, finger seals, or similar features on the outer surface of the combustion liner108. That is, as shown inFIG.10, the radially outer surface of the combustion liner108downstream of the first injector602is bare, unlike known combustors in which tear strips, seal lands, knurling, finger seals or similar features are employed. This in turn reduces the use of surfaces upstream of the combustion zone110that could otherwise lead to flame holding or flame anchoring.

FIGS.11A-11Bshow yet another example embodiment of a first injector702. In this embodiment, the plurality of first vanes716are similar in construction to the flat-surfaced embodiment shown inFIG.4and others, but in other embodiments the plurality of first vanes716could include an elliptical or similar cross-section such as the plurality of first vanes616shown inFIGS.9A-10. In this embodiment, however, the transition areas between the circumferentially stepped portions of the trailing edge728of the plurality of second vanes720include a relief cut732, as best seen inFIG.11B. Similar to the filleted or rounded transition zones632shown inFIGS.9A-10, the relief cuts732of this embodiment reduce thermal and other stresses on the plurality of second vanes720while providing enhanced mixing of compressed air and fuel at the trailing edge728of the vanes720.

In some embodiments, additive manufacturing may be employed to achieve the complex and irregular geometries of the trailing edges of the second vanes, which may otherwise be difficult to manufacture using traditional manufacturing techniques such as casting and the like. This may be more readily understood with reference toFIG.12, which is a partial cross-sectional view of the plurality of second vanes220in the first injector202discussed above in connection withFIGS.4-5C. The manufacturing techniques discussed herein would apply equally well to each of the embodiments discussed and contemplated by this disclosure.

As should be appreciated, additive manufacturing involves the building up of an article layer by layer, generally following a plurality of essentially 2D “slices” of a 3D model of the article. In this embodiment, the first injector202and/or the vanes220thereof are built up from the leading edge230to the trailing edge228, as generally indicated by the build direction arrow134shown inFIG.12. This allows for the inclusion of the complex and irregular trailing edge geometries discussed herein without the need for expensive and tedious molds and the like and while reducing or eliminating post-manufacturing machining or similar processes.

As the injector202and/or vanes220are additively manufactured, the internal passageways forming cooling channels or fuel channels (such as the fuel feed holes224and fuel injection holes226) will be integrally formed within the injector202. In some embodiments, these passageways may include a non-circular cross-section in order to aid in the additive manufacturing process. For example, as shown inFIG.12, the fuel feed hole224includes a substantially tear-drop shaped cross-sectional profile. This profile aids in the additive manufacturing process by reducing the amount of material that extends over the void of material left during the formation of a previous 2D slice of the 3D model. Put another way, the additive manufacturing process may not be able to readily accommodate overhangs of more than 45 degrees or similar without the manufactured part collapsing on itself. In this embodiment, the fuel feed holes224(and, in some embodiments, other internal passageways) include the tear-drop shaped cross-section to reduce the amount of overhang at the top half of the cross-sectional profile, thereby managing the printed ceiling of the fuel feed holes224in the printed directed and thus increasing the manufacturability of the first injector202and/or the plurality of second vanes220.

The injectors discussed herein may be additively manufactured (or otherwise manufactured such as by machining, casting, forging, etc.) from any desired material. For example, in some embodiments the injectors are manufactured from a superalloy, such as, e.g., Inconel 718 (i.e., an alloy made chiefly of nickel and chromium, with the balance formed from numerous other metals) or a similar material providing high strength and corrosion resistance. Any desired and suitable material may be employed without departing from the scope of the disclosure.

In sum, the designs and embodiments discussed herein provide increased mixing of fuel and air while providing improved flame holding or anchoring mitigation. For example, the stepped, sinusoidal, or other irregular profile of the trailing edge of the injector vanes may create one or more streamwise vortices at the trailing edge providing mixing enhancement without the inclusion of a cross-stream, planar surface that may otherwise provide a surface for flame anchoring. By increasing the mixing of the fuel and air at the injector, embodiments of the injector discussed herein lead to improved emissions by the combustor all while being streamlined and configured for flame holding resistance, leading to improved life of the injector and reduced risk of injector and/or combustor failure.

From the foregoing, it will be seen that this disclosure is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations.

ADDITIONAL CONSIDERATIONS

In this description, references to “one embodiment,” “an embodiment,” or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment,” “an embodiment,” or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments but is not necessarily included. Thus, the current technology can include a variety of combinations and/or integrations of the embodiments described herein.

In the specification and claims, reference will be made to several terms, which shall be defined to have the following meanings. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and the claim, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

As used herein, the terms “axial” and “axially” refer to directions and orientations extending substantially parallel to a center longitudinal axis of the combustor. The terms “radial” and “radially” refer to directions and orientations extending substantially perpendicular to the central axis. Moreover, directional references, such as, “top,” “bottom,” “front,” “back,” “side,” and similar terms are used herein solely for convenience and should be understood only in relation to each other. For example, a component might in practice be oriented such that faces referred to herein as “top” and “bottom” are in practice sideways, angled, inverted, etc. relative to the chosen frame of reference.

The terms “coupled,” “fixed,” “attached to,” and the like refer to both direct coupling, fixing, or attaching, as well as indirect coupling, fixing, or attaching through one or more intermediate components or features, unless otherwise specified herein.

Although the present application sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims and equivalent language. The detailed description is to be construed as exemplary only and does not describe every possible embodiment because describing every possible embodiment would be impractical. Numerous alternative embodiments may be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.

Throughout this specification, plural instances may implement components, operations, or structures described as a single instance. Although individual operations of one or more methods are illustrated and described as separate operations, one or more of the individual operations may be performed concurrently, and nothing requires that the operations be performed in the order recited or illustrated. Structures and functionality presented as separate components in example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein. The foregoing statements in this paragraph shall apply unless so stated in the description and/or except as will be readily apparent to those skilled in the art from the description.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although the disclosure has been described with reference to the embodiments illustrated in the attached figures, it is noted that equivalents may be employed, and substitutions made herein, without departing from the scope of the disclosure as recited in the claims.