COMBUSTOR WITH ADDITIVELY MANUFACTURED COMBUSTOR BODY HAVING IMPINGEMENT COOLING OF COMBUSTION LINER NEAR AFT FRAME

[0001] This application is a continuation-in-part of prior U.S. Patent Application No. 19/020,211 filed on 14 January 2025.

[0002] The disclosure relates generally to turbomachine combustors and, more specifically, to an additively manufactured combustor body including impingement cooling of a combustion liner near an aft frame.

[0003] Gas turbine systems include a combustion section including a plurality of combustors in which fuel is combusted to create a flow of combustion gas that is converted to kinetic energy in a downstream turbine section (e.g., an expansion turbine). Current combustors include a large number of parts that need to be cooled in an efficient manner. For example, a combustor may include a generally cylindrical portion of a combustion liner concentrically located inside a flow sleeve. Cooling air from a compressor discharge plenum is directed into an annulus defined between a cylindrical portion of the combustion liner and the flow sleeve(s) to cool the cylindrical portion. A tapered transition portion of the combustion liner is coupled to an aft end of the generally cylindrical portion and transitions the hot gas path from the generally cylindrical portion’s circular cross-section to a more arcuate, polygonal cross-section of a turbine inlet. The aforementioned flow sleeve may also direct cooling air along, or impinging on part of, the tapered transition portion. Air from the compressor discharge plenum may pass through impingement openings into an annulus between the transition portion and the flow sleeve.

[0004] Alternatively, air may pass into the annulus via a gap between the downstream flow sleeve and an aft frame connected to the aft end of the transition portion. The aft frame couples the tapered transition portion to the turbine inlet. Current combustors direct cooling air at or into the aft frame where the cooling air is used for convective or impingement cooling of the aft frame. However, such arrangements are not always an effective way to cool the aft frame because of, for example, its relatively large volume and its position relative to a turbine inlet. In addition, such arrangements may impede further cooling of the transition portion of the combustion liner.

[0005] All aspects, examples and features mentioned below can be combined in any technically possible way.

[0006] An aspect of the disclosure includes an additively manufactured (AM) aft frame structure, the AM aft frame structure having a one-piece member including: a combustion liner portion having a transition portion with a forward end and an aft end; an aft frame at the aft end of the transition portion, the aft frame including an inner end integral with the combustion liner portion, and an outer end configured to couple to a turbine inlet casing; a first flow sleeve portion having a forward end and an aft end, wherein the first flow sleeve portion is radially spaced apart from the transition portion and circumferentially extends around the transition portion, and wherein the aft end of the first flow sleeve portion is axially spaced from the aft frame; a circumferentially extending passage defined between the combustion liner portion and the first flow sleeve portion; a circumferential inlet to the circumferentially extending passage defined between the aft end of the first flow sleeve portion and the inner end of the aft frame; an internal impingement cavity defined by and within material of the transition portion of the combustion liner portion radially inward of the circumferential inlet; and a plurality of impingement openings defined in the transition portion of the combustion liner portion that extend from the circumferentially extending passage to the internal impingement cavity, wherein the AM aft frame structure further includes a plurality of parallel, metallurgically bonded metal layers.

[0007] Another aspect of the disclosure includes any of the preceding aspects, and wherein the material of the transition portion defines an internal coolant passage that extends from an inlet in the internal impingement cavity to an outlet at an aft end of the transition portion.

[0008] Another aspect of the disclosure includes any of the preceding aspects, and wherein the aft end of the transition portion includes an impingement cooling structure in fluid communication with the internal impingement cavity.

[0009] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement cooling structure includes an aft rail extending radially outward from the transition portion and axially spaced from the aft end of the aft frame.

[0010] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 0.1% of fluid entering the circumferential inlet to the internal impingement cavity.

[0011] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 1% of fluid entering the circumferential inlet to the internal impingement cavity.

[0012] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 5% of fluid entering the circumferential inlet to the internal impingement cavity.

[0013] Another aspect of the disclosure includes any of the preceding aspects, and further comprising a plurality of circumferentially spaced ribs extending aft from the forward end of the transition portion toward the aft frame on an exterior surface of the combustion liner portion and through the circumferential inlet to the inner end of the aft frame, thereby defining a plurality of cooling passages in the circumferentially extending passage, and wherein a radially inner edge of each rib of the plurality of circumferentially spaced ribs is radially spaced from the exterior surface of the combustion liner portion.

[0014] Another aspect of the disclosure includes an additively manufactured (AM) combustor body having a one-piece member including: a combustion liner including a transition portion; an aft frame at an aft end of the transition portion, the aft frame including an inner end integral with the combustion liner and an outer end configured to couple to a turbine inlet casing; a plurality of circumferentially spaced ribs extending forward from the inner end of the aft frame on an exterior surface of the transition portion of the combustion liner; a flow sleeve integral with the plurality of circumferentially spaced ribs and defining a circumferentially extending passage with the combustion liner and the inner end of the aft frame, wherein the flow sleeve includes an aft end; a circumferential inlet to the circumferentially extending passage defined between the aft end of the flow sleeve and the inner end of the aft frame; an internal impingement cavity defined by and within material of the transition portion of the combustion liner radially inward of the circumferential inlet; and a plurality of impingement openings defined in the transition portion of the combustion liner that extend from the circumferentially extending passage to the internal impingement cavity, wherein the AM combustor body further includes a plurality of parallel, metallurgically bonded metal layers.

[0015] Another aspect of the disclosure includes any of the preceding aspects, and wherein the material of the transition portion defines an internal coolant passage that extends from an inlet in the internal impingement cavity to an outlet at an aft end of the transition portion.

[0016] Another aspect of the disclosure includes any of the preceding aspects, and wherein the aft end of the transition portion includes an impingement cooling structure in fluid communication with the internal impingement cavity.

[0017] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement cooling structure includes an aft rail extending radially outward from the transition portion and axially spaced from the aft end of the aft frame.

[0018] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 0.1% of fluid entering the circumferential inlet to the internal impingement cavity.

[0019] Another aspect of the disclosure includes a gas turbine (GT) system, comprising: a compressor section; a combustion section operatively coupled to the compressor section; and a turbine section operatively coupled to the combustion section, wherein the combustion section includes at least one combustor including: an additively manufactured (AM) combustor body having a one-piece member including: a combustion liner including a transition portion; an aft frame at an aft end of the transition portion, the aft frame including an inner end integral with the combustion liner and an outer end configured to couple to a turbine inlet casing; a plurality of circumferentially spaced ribs extending forward from the inner end of the aft frame on an exterior surface of the transition portion of the combustion liner; a flow sleeve integral with the plurality of circumferentially spaced ribs and defining a circumferentially extending passage with the combustion liner and the inner end of the aft frame, wherein the flow sleeve includes an aft end; a circumferential inlet to the circumferentially extending passage defined between the aft end of the flow sleeve and the inner end of the aft frame; an internal impingement cavity defined by and within material of the transition portion of the combustion liner radially inward of the circumferential inlet; and a plurality of impingement openings defined in the transition portion of the combustion liner that extend from the circumferentially extending passage to the internal impingement cavity, wherein the AM combustor body further includes a plurality of parallel, metallurgically bonded metal layers.

[0020] Another aspect of the disclosure includes any of the preceding aspects, and wherein the material of the transition portion defines an internal coolant passage that extends from an inlet in the internal impingement cavity to an outlet at an aft end of the transition portion.

[0021] Another aspect of the disclosure includes any of the preceding aspects, and wherein the aft end of the transition portion includes an impingement cooling structure in fluid communication with the internal impingement cavity.

[0022] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement cooling structure includes an aft rail extending radially outward from the aft end of the transition portion and axially spaced from the aft end of the aft frame.

[0023] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 0.1% of fluid entering the circumferential inlet to the internal impingement cavity.

[0024] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 1% of fluid entering the circumferential inlet to the internal impingement cavity.

[0025] Another aspect of the disclosure includes any of the preceding aspects, and wherein the impingement openings are sized to divert at least 5% of fluid entering the circumferential inlet to the internal impingement cavity.

[0026] Two or more aspects described in this disclosure, including those described in this summary section, may be combined to form implementations not specifically described herein. That is, all embodiments described herein can be combined with each other.

[0027] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects and advantages will be apparent from the description and drawings, and from the claims.

[0038] As an initial matter, in order to clearly describe the subject matter of the current disclosure, it will become necessary to select certain terminology when referring to and describing relevant machine components within the illustrative application of a turbomachine. When doing this, if possible, common industry terminology will be used and employed in a manner consistent with its accepted meaning. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will appreciate that often a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part may include and be referenced in another context as consisting of multiple components. Alternatively, what may be described herein as including multiple components may be referred to elsewhere as a single part.

[0039] In addition, several descriptive terms may be used regularly herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, “downstream” and “upstream” are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through a combustor of the turbomachine or, for example, the flow of air through the combustor or coolant through one of the turbomachine's component systems. The term “downstream” corresponds to the direction of flow of the fluid, and the term “upstream” refers to the direction opposite to the flow. The terms “forward” and “aft,” without any further specificity, refer to directions, with “forward” referring to the front or compressor end of the turbomachine, and “aft” referring to the rearward or turbine end of the turbomachine.

[0040] The term “axial” refers to movement or position parallel to an axis, e.g., an axis of a combustor or turbomachine. The term “radial” refers to movement or position perpendicular to an axis, e.g., an axis of a combustor or a turbomachine. In cases such as this, if a first component resides closer to the axis than a second component, it will be stated herein that the first component is “radially inward” or “inboard” of the second component. If, on the other hand, the first component resides further from the axis than the second component, it may be stated herein that the first component is “radially outward” or “outboard” of the second component. Finally, the term “circumferential” refers to movement or position around an axis, e.g., a central axis of a combustion liner or a circumferential interior of casing extending about a combustor. As indicated above and depending on context, it will be appreciated that such terms may be applied in relation to the axis of the combustor or the axis of the turbomachine.

[0041] In addition, several descriptive terms may be used regularly herein, as described below. The terms “first,” “second,” and “third,” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. “Optional” or “optionally” means that the subsequently described event may or may not occur or that the subsequently described feature may or may not be present and that the description includes instances where the event occurs, or the feature is present and instances where the event does not occur, or the feature is not present.

[0043] Where an element or layer is referred to as being “on,” “engaged to,” “connected to,” “coupled to,” or “mounted to” another element or layer, it may be directly on, engaged, connected, coupled, or mounted to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The verb forms of “couple” and “mount” may be used interchangeably herein.

[0044] Embodiments of the disclosure provide a combustor for a gas turbine system, which combustor includes support, attachment, flow guiding, and cooling structures. More particularly, the combustor includes a combustor body with a combustion liner and one or more flow sleeves around the combustion liner. The combustion liner and flow sleeve(s) are supported at an aft end of the combustor by an aft frame configured to connect to an inner casing (e.g., a turbine inlet casing) of the gas turbine system. A circumferentially extending passage is defined between the flow sleeve(s) and the combustion liner, and cooling air can enter the passage near the aft frame portion and exit the passage at a forward end of the flow sleeve(s). The combustor includes additively manufactured (AM) components. For example, in embodiments, the one-piece member may include an AM aft frame structure that includes the aft frame with part or all of a transition portion of a combustion liner configured for connection to an upstream combustion liner portion of the combustor. Such an embodiment may be referred to herein as an “AM aft frame structure.” In other embodiments, the one-piece member includes larger sections of components of the combustor body, such as one or more complete portions of a combustion liner and one or more complete flow sleeves integrally formed with the aft frame and can include other parts as may be suitable and/or appropriate, such as fuel injectors and/or mounts therefor. Such an embodiment may be referred to herein as a “combustor body” and can be said to include an aft frame having similar configuration to the AM aft frame structure as in the first example above.

[0045] In both of the examples above, the combustion liner and/or the flow sleeve(s) are connected to or integrally formed with the aft frame with a plurality of ribs extending therebetween and in the circumferentially extending passage. That is, the ribs extend in a radial direction between an outer surface of the combustion liner portion and an inner surface of at least an aftmost flow sleeve, as well as axially to the aft frame. In addition to connecting the combustion liner portion, flow sleeve(s), and aft frame, the ribs define therewith cooling passages within the circumferentially extending passage and extending axially from the circumferential inlet toward the exit of the circumferentially extending passage.

[0046] In one embodiment, the one-piece member of an AM combustor body includes a combustion liner (or portion thereof) including a transition portion and an aft frame at an aft end of the transition portion. In one embodiment, the one-piece member includes a combustion liner including a transition portion and an aft frame at an aft end of the transition portion. The aft frame includes an inner end integral with the combustion liner and an outer end configured to couple to a turbine inlet casing. A flow sleeve portion has a forward end and an aft end and extends circumferentially around the transition portion. The flow sleeve portion is also radially spaced from the transition portion, and the aft end of the flow sleeve portion is axially spaced apart from the inner end of the aft frame. A circumferentially extending passage is defined between the combustion liner and the first flow sleeve portion, and a circumferential inlet to the circumferentially extending passage is defined between the aft end of the flow sleeve portion and the inner end of the aft frame.

[0047] The aft end of the transition portion includes an impingement cooling structure, such as an impingement cavity, impingement cooling holes, a coolant passage, and an aft rail. The material of the transition portion defines the internal impingement cavity and a plurality of impingement openings that extend from the circumferentially extending passage to the internal impingement cavity. The material of the transition portion also defines the coolant passage, which extends from an inlet in the internal impingement cavity to an outlet at an aft end of the transition portion. The outlet leads to an aft rail extending radially inward from the aft end of the transition structure and that is axially spaced from the aft end of the aft frame. The AM aft frame includes a plurality of parallel, metallurgically bonded, such as sintered, metal layers, as does the AM combustor body. The circumferentially extending passage, the circumferential inlet therefor, the flow sleeve portion, and the impingement cooling structure promote increased convection and conduction cooling to the aft frame without loss of structural strength.

[0048] FIG. 1 shows a functional block diagram of an illustrative gas turbine (GT) system 100 that may incorporate various embodiments of a combustor 130 of the present disclosure. As shown, GT system 100 generally includes an inlet section 112 that may include a series of filters, cooling coils, moisture separators, and/or other devices to purify and otherwise condition a working fluid 114 (e.g., air and/or recirculated exhaust gas) entering GT system 100. Working fluid 114 flows to a compressor 116 in a compressor section 118 that progressively imparts kinetic energy to working fluid 114 to produce a compressed working fluid 120 (alternatively “air 120” or “compressed air 120” hereafter for simplicity) at a highly energized state. Compressed air 120 is mixed with a fuel(s) 122 from one or more fuel source(s) 124 to form a combustible mixture within at least one combustor 130 in a combustion section 132 that is operatively coupled to compressor section 118. The combustible mixture is burned to produce combustion gases 134 having a high temperature and pressure.

[0049] Combustion gases 134 flow through a turbine 136 (e.g., an expansion turbine) of a turbine section 138 operatively coupled to combustion section 132 to produce work. For example, turbine 136 may be connected to a shaft 140 so that rotation of turbine 136 drives compressor 116 to produce compressed air 120. Alternatively, or in addition, shaft 140 may connect turbine 136 to a load such as a generator 142 for producing electricity. Exhaust gases 144 from turbine 136 flow through an exhaust section 146 that connects turbine 136 to an exhaust stack 148 downstream from turbine 136. Exhaust section 146 may include, for example, a filtering system for cleaning exhaust gases 144 and/or a heat recovery steam generator (not shown) for extracting additional heat from exhaust gases 144 before release to the environment. Where more than one combustor 130 is used, they may be circumferentially spaced around a turbine inlet casing 150 of turbine 136.

[0050] In one embodiment, GT system 100 may include an engine model from GE Vernova of Cambridge, MA. The present disclosure is not limited to any one particular GT system and may be implemented in connection with engines including, for example, any of the HA, F, B, LM, GT, TM and E-class engine models of GE Vernova, and engine models of other companies. Furthermore, the present disclosure is not limited to any particular turbomachine and may be applicable to, for example, steam turbines, jet engines, compressors, turbofans, etc.

[0051] FIG. 2 shows a cross-sectional side view of combustor 130 positioned within GT system 100 and including an additively manufactured (AM) combustor body 160 with an aft frame 190 according to embodiments of the disclosure; FIG. 3 shows a side perspective view of an additively manufactured (AM) combustor body 160 with an AM aft frame structure 158 according to embodiments; FIG. 4 shows an enlarged cross-sectional view of aft frame structure 158 of AM combustor body 160 (per dashed box in FIG. 3) with aft frame 190 thereof attached to the rest of AM combustor body 160; and FIG. 5 shows an enlarged perspective view of aft frame structure 158 of combustor body 160, according to embodiments of the disclosure.

[0052] As shown in FIG. 2, combustor 130 is at least partially surrounded by an outer casing 162 such as a compressor discharge casing and/or a turbine casing. An interior of outer casing 162 is in fluid communication with compressor section 118 (FIG. 1), e.g., compressor 116, and defines a plenum that provides a compressed air source 154 used for combustion and cooling. Combustor 130 for GT system 100 includes AM combustor body 160 including a one-piece member 164. One-piece member 164 includes a combustion liner 166 including a transition portion 170, which may be tapered from a forward end thereof to an aft end thereof. Combustion liner 166 may also include a generally cylindrical (e.g., possibly frustoconical), forward portion 168 with transition portion 170 at an aft end (right side as shown in FIGS. 2, 4) of forward portion 168. That is, transition portion 170 may be integral with an aft end of forward portion 168 of combustion liner 166 where forward portion 168 is provided as part of combustion liner 166. Transition portion 170 at an aft end of forward portion 168 transitions the hot gas path (HGP) from the generally circular cross-section of forward portion 168 to a more arcuate, polygonal cross-section for coupling to turbine inlet casing 150 of turbine 136 as illustrated in FIGS. 3 and 6.

[0053] Optionally, AM combustor body 160 may include at least one axial fuel stage (AFS) injector mount 172 directed into combustion liner 166, i.e., for mounting an AFS injector 186. As shown in FIG. 2, where two or more AFS injectors 186 are present, they are typically circumferentially spaced along at least one of forward portion 168 and/or transition portion 170, i.e., spaced around the outside of forward portion 168 and/or transition portion 170. The two or more AFS injectors 186 are typically evenly spaced apart circumferentially around combustion liner 166.

[0054] Combustion liner 166, also known as a hot gas path (HGP) duct or unibody liner, extends downstream from a separate head end fuel nozzle assembly 174 (hereafter “head end assembly 174”) and a cap assembly 176 coupled to a forward end 169 of AM combustor body 160. That is, combustor 130 may also include a separate head end assembly 174 coupled to forward end 169 of AM combustor body 160. Head end assembly 174 generally includes at least one axially extending fuel nozzle 180 that extends downstream from an end cover 182 and cap assembly 176 that extends radially and axially within outer casing 162 downstream from end cover 182. Cap assembly 176 defines the upstream boundary of the combustion chamber. Head end assembly 174 may include any now known or later developed axially extending fuel nozzles 180 for delivering fuel(s) 122 to a primary combustion zone 184. In certain embodiments, axially extending fuel nozzle(s) 180 of head end assembly 174 extend at least partially through cap assembly 176 to provide a combustible mixture of fuel(s) and compressed air 120 to primary combustion zone 184. Where provided, AFS injectors 186 may extend radially through combustion liner 166 downstream from axially extending fuel nozzle(s) 180, i.e., at AFS injector mount(s) 172. Compressed air 120 may be routed to AFS injector(s) 186 to combine with fuel(s) 122 for combustion in a secondary combustion zone 188 that is downstream from primary combustion zone 184 from a fuel source 124.

[0055] Combustor 130, i.e., AM combustor body 160, also includes an aft frame 190 at an aft end (right side in FIGS. 2 and 3) of transition portion 170. As shown in FIGS. 2 and 6, aft frame 190 includes arcuate radially inner and outer sides 70, 74 (extending in a circumferential direction) opposite circumferential sides 71, 73 (extending in a radial or generally radial direction). Aft frame 190 also includes a mounting structure 72. As seen in FIGS. 3-5, aft frame 190 includes a (radially) inner end 192 integral with combustion liner 166, a (radially) outer end 194 configured to couple to turbine inlet casing 150 (FIG. 2), i.e., using mounting structure 72. For reference purposes, aft frame 190 also includes an intermediate portion 196 between inner end 192 and outer end 194 thereof. As shown in FIG. 3, inner end 192, outer end 194 and intermediate portion 196 are defined relative to a radial direction R from a center axis A of AM combustor body 160 at AM aft frame structure 158. Hence, inner end 192 is radially inward of outer end 194 about AM combustor body 160. Inner end 192 also is integral with an aft end 202 of transition portion 170 of combustion liner 166. That is, inner end 192 is generally where aft frame 190 integrates with combustion liner 166. As shown schematically in FIGS. 3 and 4, outer end 194 can have any now known or later developed connector 72 to connect aft frame 190 to turbine inlet casing 150 so, as shown in FIG. 2, combustion gases 134 are directed into a first stage 210 of stationary nozzles 212 of turbine 136. For illustration purposes, connector 72 is shown as a cube or block, but it can have a variety of alternative shapes, sizes, configurations, etc.

[0056] Referring to FIG. 4, aft frame 190 may be part of AM aft frame structure 158, which includes a first flow sleeve portion 230. As shown in FIG. 4, transition portion 170 is integral with aft frame 190 and is configured for attachment to combustion liner 166. Likewise, first flow sleeve portion 230 is integral with aft frame 190 and can be configured for attachment to combustor body 160, such as to a second flow sleeve portion 250 of combustor body 160. First flow sleeve portion 230 extends circumferentially around transition portion 170 at a location forward of aft frame 190. First flow sleeve portion 230 is radially spaced apart from transition portion 170 (e.g., by a “sleeve gap”), includes a forward end 246, and has an aft end 232 axially spaced apart from aft frame 190. A circumferentially extending passage 200 (also referred to as “circumferential passage 200” and/or “passage 200” herein) is defined between transition portion 170 and first flow sleeve portion 230. A circumferential inlet 233 to circumferential passage 200 is defined between aft end 232 of first flow sleeve portion 230 and inner end 192 of aft frame 190.

[0057] It should be understood that, in the unitary embodiment shown in FIG. 5, AM aft frame structure 158 is integral with combustor body 160. First flow sleeve portion 230 is therefore integral with transition portion 170 and aft frame 190. For conciseness, the description may refer to “first flow sleeve portion 230” and “transition portion 170” even when describing embodiments like that shown in FIG. 5, but it should be understood that such references to “first flow sleeve portion 230” and “transition portion 170” may refer to portions of a larger, integral whole (e.g., including some or all of combustion liner 166 and/or some or all of second flow sleeve portion 250).

[0058] As shown in FIGS. 4 and 5, a plurality of circumferentially spaced ribs 220 extend in embodiments from a forward end 178 of transition portion 170 toward aft frame 190 on exterior surface 222 of combustion liner portion 166. As noted above, depending on the order of formation, circumferentially spaced ribs 220 can also be said to extend forward from aft frame 190 in certain embodiments. As additionally seen in FIG. 5, a plurality of cooling passages 240 are defined in circumferentially extending passage 200 by and between exterior surface 222 of transition portion 170 of combustion liner 166 and plurality of circumferentially spaced ribs 220. Each cooling passage 240 extends from circumferential inlet 233 to forward end 246 of first flow sleeve 230.

[0059] In embodiments, plurality of circumferentially spaced ribs 220 extend through circumferential inlet 233 to inner end 192 of aft frame 190. A radially inner edge 224 of each rib 220 of plurality of circumferentially spaced ribs 220 is radially spaced from exterior surface 222 of transition portion 170 of combustion liner portion 166 in embodiments, defining a circumferential channel 206 that allows fluid communication between cooling passages 240, such as, as particularly seen in FIGS. 4 and 5, under circumferential inlet 233. In addition, an outer edge 226 of each rib 220 can join aft end 232 of first flow sleeve 230 at any suitable point. Outer edge 226 can extend in a linear fashion for a portion of its axial length and can smoothly curve toward and join outer end 194 of aft frame 190.

[0060] As also shown in the examples shown in FIGS. 4 and 5, a plurality of circumferentially spaced openings 234 are defined circumferentially between spaced ribs 220 aft of aft end 232 of first flow sleeve portion 230 and defined axially between aft end 232 of first flow sleeve portion 230 and intermediate portion 196 of aft frame 190. Plurality of circumferentially spaced openings 234 (also referred to hereafter as “spaced openings 234”) are in and/or inward of circumferential inlet 233 and are in fluid communication with circumferentially extending passage 200 defined partially within inner end 192 of aft frame 190. In embodiments, particularly where spaced openings 234 are in circumferential inlet 233, each spaced opening 234 can be regarded as a respective cooling passage inlet. Compressed air 120 can flow from compressed air source 154 into circumferential inlet 233, into spaced openings 234 to cool aft frame 190, and then into cooling passages 240 thereafter. Such compressed air 120 can continue through cooling passages 240 toward forward end 246 of first flow sleeve portion 230.

[0061] As noted above, AM aft frame structure 158 is a separate component attached to a remainder of combustor body 160. As also noted above, an example of such an embodiment is shown in FIG. 4. In the example of FIG. 4, first flow sleeve portion 230 of AM aft frame structure 158 can be attached or connected to respective parts of the rest of combustor body 160, such as a second flow sleeve portion 250. In embodiments, second flow portion 250 forms a single flow sleeve with first flow sleeve portion 230. As also illustrated in FIG. 4, transition portion 170 of AM aft frame structure 158 can be attached/connected to the rest of combustion liner 166 of combustor body 160, such as via second transition portion 170A.

[0062] As additionally noted above, and as illustrated in FIG. 5, in other embodiments combustor 130 can include AM combustor body 160 having a one-piece member 164 that integrally includes AM aft frame 190 including identical structure to AM aft frame structure 158. That is, the parts of AM aft frame structure 158 as seen in FIG. 4 are integrated into one-piece member 164 in the example shown in FIG. 5. In such embodiments, as seen in FIG. 5, transition portion 170 is integrally formed with and is part of combustion liner 166 and AM aft frame 190. Similarly, first flow sleeve portion 230 is simply flow sleeve 230 of one-piece member 164. Thus, while FIG. 5 includes indications for AM aft frame structure 158 for association with the illustrations of FIGS. 3 and 4, it can be said that one-piece member 164 in the example of FIG. 5 includes combustion liner 166 with transition portion 170, includes flow sleeve 230, and includes aft frame 190, all as a single, unitary part.

[0063] As in earlier embodiments, flow sleeve 230 is spaced from exterior surface 222 of transition portion 170 by a sleeve gap to define at least one cooling passage 240 in circumferentially extending passage 200. The sleeve gap results from plurality of circumferentially spaced ribs 220 integrally formed with flow sleeve 230 and transition portion 170 of combustion liner 166. Thus, flow sleeve 230, spaced ribs 220, and transition portion 170 collectively define a plurality of cooling passages 240. More particularly, flow sleeve 230, spaced ribs 220, and exterior surface 222 of combustion liner 166 at transition portion 170 define plurality of cooling passages 240 therebetween within circumferentially extending passage 200. Spaced ribs 220 extend forward from inner end 192 of aft frame 190 to forward end 246 of flow sleeve 230. That is, spaced ribs 220 extend along an entirety of the axial length of flow sleeve 230, resulting in cooling passages 240 that extend in a generally axial direction.

[0064] A circumferential inlet 233 to circumferentially extending passage 200 is defined between an aft end 232 of flow sleeve 230 and inner end 192 of aft frame 190. Across this axial span, inner edges 224 of ribs 220 are spaced apart from exterior surface 222 of transition portion 170, such that a circumferential channel 206 is defined within the circumferentially extending passage 200 beneath inner edges 224 of ribs 220, which allows communication between cooling passages 240 in circumferential inlet 233. With this configuration, as noted, compressed air 120 from compressed air source 154 may enter circumferential inlet 233 and pass through spaced openings 234 to enter circumferential passage 200 in aft frame 190. In embodiments, air in circumferential passage 200 and/or circumferential channel 206 can circulate circumferentially (or partially circumferentially at numerous locations) to cool aft frame 190. In addition, compressed air 120 from compressed air source 154 may pass forward through cooling passages 240 between spaced ribs 220, exterior surface 222 of combustion liner 166 (i.e., transition portion 170 thereof) and flow sleeve 230. Compressed air 120 passing forward through cooling passages 240 serves to at least cool exterior surface 222 of combustion liner 166 (i.e., transition portion 170 thereof).

[0065] Circumferentially extending passage 200 is defined relative to center axis A of AM combustor body 160 at AM aft frame structure 158 (FIGS. 3, 6). Passage 200 is described as “partially within” inner end 192 because it is open in the forward direction, i.e., toward head end assembly 174. Hence, as shown in FIG. 4, inner end 192 may have a smaller axial thickness T near combustion liner 166 compared to outer end 194 and/or intermediate portion 196 of aft frame 190. In FIG. 4, circumferentially extending passage 200 (hereafter “passage 200”) extends into the page.

[0066] FIG. 6 shows a cross-sectional view of aft frame 190 along view line 6-6 in FIG. 4. As shown in FIG. 6, passage 200 may follow whatever shape aft frame 190 has at AM aft frame structure 158, around aft end of combustion liner 166. For example, it will be recognized that aft frame 190 may have a partially arcuate, rounded rectangular, cross-sectional shape at AM aft frame structure 158 such that passage 200 has that shape. In other examples, passage 200 may not exactly follow the cross-section of aft frame 190. Referring to FIGS. 4-6, as noted above, AM combustor body 160 includes plurality of circumferentially spaced ribs 220 (hereafter “spaced ribs 220” for brevity), which extend from forward end 178 of transition portion 170 of combustion liner 166 toward inner end 192 of aft frame 190. At least part of each rib 220 extends along on an exterior surface 222 of transition portion 170 of combustion liner 166. Spaced ribs 220 can also be said to extend forward from inner end 192 of aft frame 190 toward head end assembly 174 (FIG. 2). Spaced ribs 220 are integral with first flow sleeve portion 230/flow sleeve 230 in embodiments. That is, through the additive manufacture, first flow sleeve portion 230/flow sleeve 230 shares metal layers with spaced ribs 220, and both are part of one-piece member 164 (FIG. 2) of AM combustor body 160. Spaced ribs 220 also extend radially outward relative to center axis A of AM combustor body 160 at AM aft frame structure 158 from exterior surface 222 of at least a portion of transition portion 170 of combustion liner 166.

[0067] In some embodiments, the radially inner edges 224 (FIGS. 4 and 5) of spaced ribs 220 in the vicinity of circumferential inlet 233 may be provided with one or more features, which can include arches or other arcuate portions, to space radially inner edges 224 from exterior surface 222 to define a circumferential channel 206 with inner end 192. Spaced ribs 220 do not disrupt or block circumferential channel 206, which is continuous about transition portion 170 between radially inner edges 224 and exterior surface 222 in the vicinity of circumferential inlet 233. In similar fashion, outer edges 226 of spaced ribs 220 can also include features, such as arcuate or other profiles, to enhance flow through circumferential inlet 233. In any event, spaced ribs 220 provide sufficient structural support to aft frame 190 such that the presence of circumferential channel 206, partially defined by and in inner end 192 of aft frame 190, does not create any structural weakness compared to conventional aft frames that do not include passage 200.

[0068] As shown in FIGS. 2 and 4, AM combustor body 160 may also optionally include a second flow sleeve portion 250 extending in a spaced manner around combustion liner 166 and coupled to forward end 246 of first flow sleeve portion 230. Spaced ribs 220 allow for a sliding interface (see FIG. 4) between first and second flow sleeve portions 230, 250 and eliminate the need for stiffeners that are conventionally required to structurally support one or more flow sleeves about a combustion liner 166. First and second flow sleeve portions 230, 250 may be more permanently coupled using any known solution, e.g., welds or fasteners. Spaced ribs 220 in embodiments stop at forward end 246 of first flow sleeve portion 230 such that second flow sleeve portion 250 defines an annular cooling passage 252 in fluid communication with plurality of cooling passages 240. Hence, compressed air 120 flowing in cooling passages 240 passes through annular cooling passage 252.

[0069] Second flow sleeve portion 250 may include a sleeve that is solid or that includes impingement openings (not shown). Second flow sleeve portion 250 is shown in FIG. 4 as separate from AM aft frame structure 158 and may be made of, for example, a sheet metal, but second flow sleeve portion 250 can instead be part of one-piece member 164 of AM combustor body 160 if desired and/or appropriate. Compressed air 120 passing through cooling passages 240 enters annular cooling passage 252 within second flow sleeve 250, and compressed air 120 may be used to feed combustion in, for example, AFS injectors 186 (FIG. 2) or head end assembly 174 (FIG. 2). Second flow sleeve 250 may extend forwardly any desired extent to, for example, fluidly connect to AFS injector(s) 186 and/or head end assembly 174. As shown, for example, in FIGS. 3 and 5, where second flow sleeve 250 is not provided, compressed air 120 may exit cooling passages 240 to compressed air source 154 for re-use.

[0070] As shown in FIGS. 4 and 5, in some embodiments, first flow sleeve 230 may diverge from exterior surface 222 of transition portion 170 from aft end 232 thereof to a forward end 246 thereof. More particularly, a distance D1 between aft end 232 of first flow sleeve 230 and exterior surface 222 of transition portion 170 at aft end 232 thereof is smaller than a distance D2 between first flow sleeve 230 and exterior surface 222 of transition portion 170 at forward end 246 thereof. In other embodiments, although not shown, first flow sleeve 230 may be parallel to exterior surface 222 of transition portion 170 from aft end 232 thereof to forward end 246 thereof.

[0071] As shown in FIG. 5, AM combustor body 160 may optionally include a plurality of cooling enhancement structures 244 on exterior surface 222 of transition portion 170. Cooling enhancement structures 244 may include any form of protrusions configured to create non-laminar flow such as but not limited to ribs, bumps, chevrons and/or posts. Alternatively, or additionally, cooling enhancement structures 244 may include any form of recess configured to create non-laminar flow such as but not limited to trenches and recessed openings (divots). The spacing and location of cooling enhancement structures 244 can take any form to provide the desired cooling, e.g., between spaced ribs 220, within passages 240. Although not shown, cooling enhancement structures 244 may also be located within passage 200, on spaced ribs 220 and/or within or extending from a radially inward facing surface 248 of first flow sleeve/portion 230.

[0072] With continuing reference to FIG. 5, in other embodiments, aft frame structure 158 includes a cooling feature 251, such as an impingement cooling feature. In the example shown, cooling feature 251 includes a plurality of (impingement) openings 254 in transition portion 170 leading from circumferential channel 206 in passage 200 and/or circumferential inlet 233 to an internal impingement cavity 256. The material of transition portion 170 defines internal impingement cavity 256 radially inward of circumferential inlet 233. Impingement openings 254 are defined in transition portion 170 and extend from circumferentially extending passage 200 to internal impingement cavity 256. Impingement openings 254 are thus in fluid communication with compressed air source 154 via circumferential inlet 233 and circumferentially extending passage 200.

[0073] As seen in the example illustrated in FIG. 5, the material of transition portion 170 in embodiments defines a coolant passage 260 with an inlet 262 in internal impingement cavity 256 and an outlet 264 at aft end 202 of transition portion 170. Outlet 264 is located in proximity to an aft rail 266 extending radially from aft end 202 of transition portion 170 and axially spaced from aft frame 190. Any number of impingement openings 254, internal impingement cavities 256, and/or coolant passages 260 can be used. Likewise, for a given coolant passage 260, any number of inlets 262 and/or outlets 264 can be used. In addition, any number of cooling features 251 can be employed.

[0074] In the configuration shown in FIG. 5, compressed air 120 from compressed air source 154 may: enter circumferential inlet 233 and/or spaced openings 234 and pass or remain aft to enter circumferential channel 206 and circulate circumferentially (or partially circumferentially at numerous locations) to cool aft frame 190 and transition portion 170; enter spaced openings 234 and pass forward to enter cooling passages 240 between spaced ribs 220, exterior surface 222 of combustion liner 166 (i.e., transition portion 170 thereof) and first flow sleeve/portion 230; and/or pass through openings 254 in transition portion 170 to enter internal impingement cavity 256 to provide impingement cooling to interior surface 167 of combustion liner 166 (i.e., transition portion 170 thereof) via radially inner surface 258 of internal impingement cavity 256. Compressed air 120 passing through impingement openings 254 enters internal impingement cavity 256 and strikes or impinges on a radially inner surface 258 of internal impingement cavity 256. After passing through openings 254 and impinging on radially inner surface 258, the post-impingement air (not separately labeled) may then pass aftward to coolant passage 260 via inlet 262 and exit via outlet 264 to cool aft rail 266 of combustion liner 166 (i.e., transition portion 170 thereof).

[0075] In one or more embodiments, the impingement openings 254 are sized to divert at least 0.1% of fluid entering the circumferential inlet 233 to the internal impingement cavity 256. In one or more embodiments, the impingement openings 254 are sized to divert at least 1% of fluid entering the circumferential inlet 233 to the internal impingement cavity 256. In one or more embodiments, the impingement openings 254 are sized to divert at least 5% of fluid entering the circumferential inlet 233 to the internal impingement cavity 256. Such levels of fluid diversion are sufficient for cooling aft end 202 of transition portion 170 and/or aft frame 190.

[0076] Returning to FIG. 2, combustor 130 generally terminates at a point that is adjacent to first stage 210 of stationary nozzles 212 of turbine 136. Combustion liner 166 at least partially defines a hot gas path (HGP) for routing combustion gases 134 from primary combustion zone 184 and secondary combustion zone 188 to turbine inlet casing 150 of turbine 136 during operation of GT system 100. In operation, compressed air 120 flows from compressor 116 and is routed through various fluid flow passage(s). A portion of compressed air 120 is routed to head end assembly 174 of combustor 130 through second flow sleeve 250 or other flow passage(s) where it reverses direction and is directed through axially extending fuel nozzle(s) 180. Compressed air 120 is mixed with fuel(s) 122 to form a first combustible mixture that is injected into primary combustion zone 184. The fuel may be the same fuel(s) 122 supplied from fuel source(s) 124 to AFS injectors 186, or it may be a different fuel or a different fuel source. The first combustible mixture is burned to produce combustion gases 134. A second portion of compressed air 120 may be routed through the radially extending AFS injector(s) 186 where it is mixed with fuel(s) 122 from fuel passages (e.g., conduits from fuel source(s) 124 provided as external tubes (shown) or in second flow sleeve(s) 250) to form a second combustible mixture. The second combustible mixture is injected through combustion liner 166 and into the hot gas path (HGP). The second combustible mixture at least partially mixes with combustion gases 134 and is burned in secondary combustion zone 188. Combustion liner 166 at least partially defines hot gas path (HGP) for routing combustion gases 134 from primary combustion zone 184 and secondary combustion zone 188 to turbine inlet casing 150 of turbine 136 during operation of GT system 100.

[0077] As GT system 100 operates, compressed air 120 also enters spaced openings 234 in AM aft frame structure 158 to cool aft frame 190 through passage 200 (and perhaps cooling feature(s) 251), and cool transition portion 170 of combustion liner 166 of AM combustor body 160. Some of compressed air 120 forward of aft frame 190 may enter cooling passages 240 between first flow sleeve 230, exterior surface 222 of transition portion 170 and spaced ribs 220 and may be directed forwardly. Where a second flow sleeve 250 is provided, compressed air 120 in cooling passages 240 may be directed to AFS injector(s) 186 (FIG. 2) or head end assembly 174 (FIG. 2) where it is used for combustion with fuel(s) 122.

[0078] Embodiments of the disclosure may also include, as shown in FIGS. 1-2, GT system 100 including compressor section 118, combustion section 132 operatively coupled to compressor section 118, and turbine section 138 operatively coupled to combustion section 132. Combustion section 132 includes at least one combustor 130 including AM combustor body 160 including one-piece member 164, as described herein.

[0079] As noted, AM combustor body 160 and/or AM aft frame structure 158 may be additively manufactured using any now known or later developed technique capable of forming the large, integral body. As a result of the additive manufacturing, there are no mechanical connections between the various parts in AM combustor body 160 (i.e., it is all one-piece). FIG. 8 shows a cross-sectional view of any portion of additively manufactured combustor body 160. As shown in FIG. 8, AM combustor body 160 and/or AM aft frame structure 158 includes a plurality of parallel, metallurgically bonded metal layers 280, i.e., from the additive manufacturing thereof. In embodiments, metal layers 280 are metallurgically bonded by sintering, though other forms of metallurgical bonding can be used instead of and/or in addition to sintering if desired and/or appropriate.

[0080] FIG. 7 shows a schematic/block view of an illustrative computerized metal powder additive manufacturing system 310 (hereinafter “AM system 310”) for generating AM combustor body 160, of which only a single layer is shown. The teachings of the disclosures will be described relative to building AM combustor body 160 using multiple melting beam sources 312, 314, 316, 318, but it is emphasized and will be readily recognized that the teachings of the disclosure are equally applicable to build AM combustor body 160 using any number of melting beam sources. In this example, AM system 310 is arranged for direct metal laser melting (DMLM). It is understood that the general teachings of the disclosure are equally applicable to other forms of metal powder additive manufacturing such as but not limited to selective laser melting (SLM), and perhaps other forms of additive manufacturing (i.e., other than metal powder applications). The layer of AM combustor body 160 in build platform 320 is illustrated as a circular element in FIG. 7; however, it is understood that the additive manufacturing process can be readily adapted to manufacture any shape on build platform 320.

[0081] AM system 310 generally includes an additive manufacturing control system 330 (“control system”) and an AM printer 332. As will be described, control system 330 executes set of computer-executable instructions or code 334 to generate AM combustor body 160 using multiple melting beam sources 312, 314, 316, 318. In the example shown, four melting beam sources may include four lasers. However, the teachings of the disclosures are applicable to any melting beam source, e.g., an electron beam, laser, etc. Control system 330 is shown implemented on computer 336 as computer program code. To this extent, computer 336 is shown including a memory 338 and/or storage system 340, a processor unit (PU) 344, an input/output (I/O) interface 346, and a bus 348. Further, computer 336 is shown in communication with an external I/O device/resource 350. In general, processor unit (PU) 344 executes computer program code 334 that is stored in memory 338 and/or storage system 340. While executing computer program code 334, processor unit (PU) 344 can read and/or write data to/from memory 338, storage system 340, I/O device 350 and/or AM printer 332. Bus 348 provides a communication link between each of the components in computer 336, and I/O device 350 can comprise any device that enables a user to interact with computer 336 (e.g., keyboard, pointing device, display, etc.).

[0082] Computer 336 is only representative of various possible combinations of hardware and software. For example, processor unit (PU) 344 may comprise a single processing unit or be distributed across one or more processing units in one or more locations, e.g., on a client and server. Similarly, memory 338 and/or storage system 340 may reside at one or more physical locations. Memory 338 and/or storage system 340 can comprise any combination of various types of non-transitory computer readable storage medium including magnetic media, optical media, random access memory (RAM), read only memory (ROM), etc. Computer 336 can comprise any type of computing device such as an industrial controller, a network server, a desktop computer, a laptop, a handheld device, etc.

[0083] As noted, AM system 310, and in particular, control system 330, executes code 334 to generate AM combustor body 160. Code 334 can include, among other things, a set of computer-executable instructions 334S (herein also referred to as ‘code 334S’) for operating a system (i.e., AM printer 332) and a set of computer-executable instructions 334O (herein also referred to as ‘code 334O’) for defining an object (i.e., AM combustor body 160) to be physically generated by AM printer 332. As described herein, additive manufacturing processes begin with a non-transitory computer readable storage medium (e.g., memory 338, storage system 340, etc.) storing code 334. Set of computer-executable instructions 334S for operating AM printer 332 may include any now known or later developed software code capable of operating AM printer 332.

[0084] The set of computer-executable instructions 334O defining AM combustor body 160 may include a precisely defined 3D model of AM combustor body 160 and can be generated from any of a large variety of well-known computer aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc. In this regard, code 334O can include any now known or later developed file format. Furthermore, code 334O representative of the part to be built, e.g., AM combustor body 160, may be translated between different formats. For example, code 334O may include Standard Tessellation Language (STL) files which was created for stereolithography CAD programs of 3D Systems, or an additive manufacturing file (AMF), which is an American Society of Mechanical Engineers (ASME) standard that is an extensible markup-language (XML) based format designed to allow any CAD software to describe the shape and composition of any three-dimensional object to be fabricated on any AM printer. Code 334O representative of AM combustor body 160 may also be converted into a set of data signals and transmitted, received as a set of data signals and converted to code, stored, etc., as necessary. Code 334O may be configured according to embodiments of the disclosure to allow for formation of border and internal sections in overlapping field regions, as will be described. In any event, code 334O may be an input to AM system 310 and may come from a part designer, an intellectual property (IP) provider, a design company, the operator or owner of AM system 310, or from other sources. In any event, control system 330 executes code 334S and 334O, dividing AM combustor body 160 into a series of thin slices that assembles using AM printer 332 in successive layers of material.

[0085] AM printer 332 may include a processing chamber 360 that is sealed to provide a controlled atmosphere for AM combustor body 160 printing. A build platform 320, upon which AM combustor body 160 is/are built, is positioned within processing chamber 360. A number of melting beam sources 312, 314, 316, 318 are configured to melt layers of metal powder on build platform 320 to generate AM combustor body 160. While four melting beam sources 312, 314, 316, 318 are illustrated, it is emphasized that the teachings of the disclosure are applicable to a system employing any number of sources, e.g., 1, 2, 3, or 5 or more. As understood in the field, each melting beam source 312, 314, 316, 318 may have a field including a non-overlapping field region, respectively, in which it can exclusively melt metal powder, and may include at least one overlapping field region in which two or more sources can melt metal powder. In this regard, each melting beam source 312, 314, 316, 318 may generate a melting beam, respectively, that fuses particles for each slice, as defined by code 334O. For example, in FIG. 7, melting beam source 312 is shown creating a layer of AM combustor body 160 using melting beam 362 in one region, while melting beam source 314 is shown creating a layer of AM combustor body 160 using melting beam 362’ in another region. Each melting beam source 312, 314, 316, 318 is calibrated in any now known or later developed manner. That is, each melting beam source 312, 314, 316, 318 has had its laser or electron beam’s anticipated position relative to build platform 320 correlated with its actual position in order to provide an individual position correction (not shown) to ensure its individual accuracy. In one embodiment, each of plurality of melting beam sources 312, 314, 316, 318 may create melting beams, e.g., 362, 362’, having the same cross-sectional dimensions (e.g., shape and size in operation), power and scan speed.

[0086] Continuing with FIG. 7, an applicator (or re-coater blade) 370 may create a thin layer of raw material 372 spread out as the blank canvas from which each successive slice of the final AM combustor body 160 will be created. Various parts of AM printer 332 may move to accommodate the addition of each new layer, e.g., a build platform 320 may lower and/or chamber 360 and/or applicator 370 may rise after each layer. The process may use different raw materials in the form of fine-grain metal powder, a stock of which may be held in a chamber 368 accessible by applicator 370.

[0087] Processing chamber 360 is filled with an inert gas such as argon or nitrogen and controlled to reduce or eliminate oxygen. Control system 330 is configured to control a flow of a gas mixture 374 within processing chamber 360 from a source of inert gas 376. In this case, control system 330 may control a pump 380, and/or a flow valve system 382 for inert gas to control the content of gas mixture 374. Flow valve system 382 may include one or more computer controllable valves, flow sensors, temperature sensors, pressure sensors, etc., capable of precisely controlling flow of the particular gas. Pump 380 may be provided with or without valve system 382. Where pump 380 is omitted, inert gas may simply enter a conduit or manifold prior to introduction to processing chamber 360. Source of inert gas 376 may take the form of any conventional source for the material contained therein, e.g., a tank, reservoir or other source. Any sensors (not shown) required to measure gas mixture 374 may be provided. Gas mixture 374 may be filtered using a filter 386 in a conventional manner.

[0088] In operation, build platform 320 with metal powder thereon is provided within processing chamber 360, and control system 330 controls flow of gas mixture 374 within processing chamber 360 from source of inert gas 376. Control system 330 also controls AM printer 332, and in particular, applicator 370 and melting beam sources 312, 314, 316, 318 to sequentially melt layers of metal powder on build platform 320 to generate the desired part according to embodiments of the disclosure. While a particular AM system 310 has been described herein, it is emphasized that the teachings of the disclosure are not limited to any particular additive manufacturing system or method.

[0089] The disclosure provides various technical and commercial advantages, examples of which are discussed herein. The AM combustor body and/or AM aft frame structure having the circumferentially extending passage partially in the inner end of the aft frame, the spaced ribs, the first flow sleeve portion, and the impingement cooling structure promotes increased convection and conduction cooling to the aft frame and the transition portion of the combustion liner without loss of structural strength. The spaced ribs also allow a sliding interface with a second flow or impingement sleeve without the need for stiffeners for that second flow sleeve or impingement sleeve. In one or more embodiments, cooling passages defined by the ribs, the first flow sleeve, and the transition portion of the combustion liner can enhance the cooling of the transition portion. In one or more embodiments, cooling channels and/or impingement cooling structure may also be included in the aft frame to promote cooling thereof.

[0090] Approximating language, as used herein throughout the specification and claims, 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,” “generally” 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. Here and throughout the specification and claims, 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. “Approximately” or “about,” as applied to a particular value of a range, applies to both end values and, unless otherwise dependent on the precision of the instrument measuring the value, may indicate +/- 10% of the stated value(s).

[0091] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.