Ceramic matrix composite component comprising cooling channels and method of production thereof

Abstract

A ceramic matrix composite (CMC) component and method of manufacture including one or more elongated functional features in the CMC component. The CMC component includes a plurality of longitudinally extending ceramic matrix composite layers in a stacked configuration. Each of the one or more elongated functional features includes an inlet in fluid communication with a source of a cooling fluid flow. The CMC component further includes one or more apertures that cut through the plurality of longitudinally extending ceramic matrix composite layers from at least one of the one or more elongated functional features to an outlet proximate an outer surface of the ceramic matrix composite to form a cooling channel. The component can optionally include one or more film cooling apertures that cut through the plurality of longitudinally extending ceramic matrix composite layers from an inner surface of the ceramic matrix composite component to an outlet proximate an outer surface of the ceramic matrix composite component.

Description

[0001] This application is a divisional application of the invention patent application filed on December 18, 2020, with application number 202011509001.0 and the invention title "Ceramic-based composite component including cooling channels and method of manufacturing thereof". Technical Field

[0002] The present invention generally relates to gas turbines for power generation, and more specifically to a method for forming ceramic-based composite components for hot gas path turbine components of gas turbines. Background Technology

[0003] Silicon carbide (SiC)-based ceramic matrix composite (CMC) materials have been proposed as materials for certain components of gas turbine engines, such as turbine blades, impellers, nozzles, shrouds, and buckets. Several methods are known for manufacturing SiC-based components, including Silicomp, melt infiltration (MI), chemical vapor infiltration (CVI), polymer expansion pyrolysis (PIP), and oxide / oxide methods. Although these manufacturing techniques differ significantly from one another, each involves the use of hand lay-up and machining tools or dies to produce near-net-shape parts by incorporating heat application at various process stages.

[0004] Similar to turbine blades and impellers formed from more conventional superalloy materials, CMC blades, impellers, and shrouds are primarily equipped with cavities and cooling gaps to reduce weight, decrease centrifugal load, and lower component operating temperatures. These features are typically formed in CMC components using a combination of removable and consumable tools, drilling, etc. Internal cooling channels facilitate the cooling of the metal and the CMC hot gas path hardware because they reduce cooling flow requirements and thermal gradient / stress.

[0005] In many cases, CMC gas turbine components are subjected to extreme conditions in the form of extreme thermal gradients and high temperatures. Even with cavities and cooling gaps in CMC components as previously mentioned, extreme conditions can drive crack formation, coating peeling, and degradation within the components. The reduced service life resulting from these problems prevents CMC components from realizing their full potential.

[0006] Therefore, there is a need for a ceramic matrix composite component and a method for producing such a component, which provides improved cooling for CMC gas turbine components when subjected to extreme conditions, such as extreme thermal gradients and high temperatures. Summary of the Invention

[0007] The aspects and advantages of this disclosure will be set forth in part in the description which follows, or may be apparent from the description, or may be learned by practice of this disclosure.

[0008] A ceramic matrix composite (CMC) component is generally provided, as well as a method of forming the CMC component. In one embodiment, the CMC component includes: a plurality of longitudinally extending CMC layers, the plurality of longitudinally extending CMC layers being stacked to form a dense body; one or more elongated functional features, the one or more elongated functional features being formed in the dense body and aligned with the plurality of longitudinally extending CMC layers; and one or more orifices, the one or more orifices cutting through the plurality of longitudinally extending CMC layers from at least one of the one or more elongated functional features to an outlet adjacent to an outer surface of the CMC component. Each of the one or more elongated functional features includes an inlet in fluid communication with a cooling fluid flow from a fluid source.

[0009] In another embodiment, a ceramic matrix composite component includes: a plurality of longitudinally extending ceramic matrix composite layers, the plurality of longitudinally extending ceramic matrix composite layers forming a dense body in a stacked structure; one or more elongated functional features, the one or more elongated functional features being formed in the dense body; and one or more orifices, the one or more orifices cutting through the plurality of longitudinally extending ceramic matrix composite layers from at least one of the one or more elongated functional features to an outlet adjacent to an outer surface of the ceramic matrix composite to form at least one cooling channel. Each of the one or more elongated functional features includes an inlet in fluid communication with a cooling fluid flow from a fluid source. At least one of the one or more elongated functional features is configured to retain the fluid flow from the fluid source within the elongated functional feature to form an isolation channel.

[0010] In yet another embodiment, a method of forming a ceramic matrix composite product includes: forming a CMC preform comprising a matrix precursor, a plurality of reinforcing fibers, and a plurality of sacrificial fibers; performing one of the following operations: removing the plurality of sacrificial fibers such that one or more elongated functional features in the CMC preform are formed in fluid communication with a source of cooling fluid flow; or applying a fluid penetrant to the CMC preform to densify the CMC preform; performing another of the following operations: removing the plurality of sacrificial fibers such that one or more elongated functional features in the CMC preform are formed in fluid communication with a source of cooling fluid flow; or applying a fluid penetrant to the CMC preform to densify the CMC preform; and forming one or more pores, the one or more pores cutting through at least one of the one or more elongated functional features through a plurality of longitudinally extending ceramic matrix composite layers to an outlet adjacent to an outer surface of the ceramic matrix composite component to provide fluid flow from a fluid source to the exterior of the ceramic matrix composite component and to form one or more cooling channels.

[0011] These and other features, aspects, and advantages of this disclosure will be better understood by referring to the following description and the appended claims. Embodiments of this disclosure are illustrated in conjunction with the accompanying drawings, which are incorporated in and form part of this specification, and serve to explain the principles of this disclosure. Attached Figure Description

[0012] The specification provides a complete and feasible disclosure, including its best mode, for those skilled in the art, wherein reference is made to the accompanying drawings, wherein:

[0013] Figure 1 This is a perspective view of a ceramic-based component (CMC) according to one or more embodiments disclosed herein, and more specifically, a CMC nozzle;

[0014] Figure 2 It is based on one or more embodiments disclosed herein. Figure 1 Ceramic matrix composite (CMC) components along Figure 1 The cross-sectional view taken in direction 2-2;

[0015] Figure 3 This is a perspective view of a ceramic-based component (CMC) according to one or more embodiments disclosed herein, and more specifically, another embodiment of a CMC blade;

[0016] Figure 4 It is based on one or more embodiments disclosed herein. Figure 1 A portion of the ceramic matrix composite (CMC) component along Figure 1 A schematic cross-sectional view taken in direction 4-4;

[0017] Figure 5 It is based on one or more embodiments disclosed herein. Figure 1 A portion of the ceramic matrix composite (CMC) component along Figure 1 A schematic cross-sectional view taken in direction 5-5;

[0018] Figure 6 It is based on one or more embodiments disclosed herein. Figure 3 A schematic diagram of a portion of a ceramic matrix composite (CMC) component, with one or more functional features shown by hidden lines; and

[0019] Figure 7 A method for forming a CMC component according to one or more embodiments disclosed herein is illustrated schematically.

[0020] Wherever possible, the same reference numerals will be used to denote the same parts in all the accompanying drawings. Detailed Implementation

[0021] For example, embodiments of this disclosure enable the formation of one or more cooling channels in a CMC airfoil component, wherein the channels are configured to align with one or more CMC layers, compared to concepts that fail to include one or more features disclosed herein. The inclusion of cooling channels aligned with one or more CMC layers provides for the maintenance of component structural integrity. The CMC airfoil component also includes one or more isolation channels or one or more film cooling holes. The method according to this disclosure offers reduced complexity and low cost, and more efficient cooling with the ability to reduce the cooling requirements and flow rates of the parts.

[0022] When describing the elements of various embodiments of the invention, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be other elements besides those listed. Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of illustration and not limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from its scope or spirit. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the present disclosure is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0023] In this disclosure, when layers are described as being "on" or "above" another layer or substrate, it should be understood that these layers may be in direct contact with each other or have another layer or feature between them, unless explicitly stated otherwise. Therefore, these terms simply describe the relative positions of the layers to each other and do not necessarily mean "on top of," as the relative position of "above" or "below" depends on the orientation of the device relative to the viewer.

[0024] In this disclosure, chemical elements are discussed using their common chemical abbreviations, such as those found in the periodic table. For example, hydrogen will be represented by its common chemical abbreviation H; helium will be represented by its common chemical abbreviation He; and so on.

[0025] As used herein, “average particle size” or “average fiber diameter” refers to the diameter of a particle or fiber such that approximately 50% of the particles or fibers have a diameter greater than that diameter and approximately 50% of the particles or fibers have a diameter less than that diameter.

[0026] As used herein, “substantially” means at least about 90% or more of the group being described. For example, as used herein, “substantially all” means at least about 90% or more of the corresponding group has the applicable trait, and “substantially none” or “substantially absent” means at least about 90% or more of the corresponding group does not have the applicable trait. As used herein, “most” means at least about 50% or more of the group being described. For example, as used herein, “mostly” means at least about 50% or more of the corresponding group has the applicable trait.

[0027] This document generally provides ceramic matrix composite products (“CMC products”), particularly ceramic matrix composite products formed by melt infiltration, and methods for forming such products. CMC products consist of multiple layups, including one or more elongated functional features aligned with the multiple layups, and one or more isolation channels or one or more film cooling holes aligned with the multiple layups, which together enhance the functionality of the CMC component.

[0028] Systems used for power generation include, but are not limited to, gas turbines, steam turbines, and other turbine components for power generation, such as land-based aerospace derivatives. In some applications, power generation systems that include turbomachinery (e.g., turbines, compressors, and pumps) and other machinery may include components exposed to severe wear conditions. For example, certain power generation system components, such as blades, buckets, housings, rotors, shafts, shrouds, nozzles, etc., may operate in high-temperature and / or high-speed environments. These components are manufactured using ceramic matrix composites, and these components may also include cooling passages and isolation passages. This disclosure provides a CMC component including one or more cooling passages or channels, and a method for forming a ceramic matrix composite (CMC) component. Exemplary embodiments of this disclosure are provided in... Figure 1-6 The part shown is a turbine airfoil, and more specifically a nozzle or turbine blade, but this disclosure is not limited to the structure shown.

[0029] Now for reference Figure 1 and 2 , Figure 1 A perspective view of component 10 is shown, which includes, for example but not limited to, turbine nozzle section 12 including turbine airfoil 14. Figure 2 The middle shows along Figure 1 The side cross-sectional view of nozzle segment 12 taken from line 2-2. Although Figure 1 and Figure 2 Turbine nozzle section 12 is shown, but according to this disclosure, other suitable components include, but are not limited to, combustor liners, blades, nozzle endwalls / bands, blade platforms, shrouds, or other hot gas path components. Component 10 is preferably formed of a ceramic matrix composite (CMC) material.

[0030] As used herein, ceramic matrix composite or “CMC” refers to a composite comprising a ceramic matrix reinforced by ceramic fibers. Examples of CMCs that may be used herein include, but are not limited to, materials having a matrix and reinforcing fibers, the reinforcing fibers including oxides, carbides, nitrides, carbon oxides, oxynitrides, and mixtures thereof. Examples of non-oxide materials include, but are not limited to, CMCs having a silicon carbide matrix and silicon carbide fibers (which, when manufactured by silicon melt infiltration, would contain residual free silicon); silicon carbide / silicon matrix mixtures and silicon carbide fibers; silicon nitride matrix and silicon carbide fibers; and silicon carbide / silicon nitride matrix mixtures and silicon carbide fibers. Furthermore, CMCs may have a matrix and reinforcing fibers composed of oxide ceramics. Specifically, oxide-oxide CMCs may consist of a matrix and reinforcing fibers comprising oxide-based materials such as alumina (Al₂O₃), silicon dioxide (SiO₂), aluminosilicates, and mixtures thereof. Therefore, as used herein, the term "ceramic matrix composite" includes, but is not limited to, carbon fiber reinforced carbon (C / C), carbon fiber reinforced silicon carbide (C / SiC), and silicon carbide fiber reinforced silicon carbide (SiC / SiC). In one embodiment, ceramic matrix composite materials exhibit increased elongation, fracture toughness, thermal shock resistance, and anisotropy compared to (unreinforced) monolithic ceramic structures.

[0031] Several methods exist for manufacturing SiC-SiC CMCs. In one method, the matrix is ​​partially formed or densified by infiltrating (MI) silicon or alloyed silicon into the CMC preform. In another method, the matrix is ​​at least partially formed by chemical vapor infiltration (CVI) of silicon carbide into the CMC preform. In a third method, the matrix is ​​at least partially formed by pyrolyzing a pre-ceramic polymer produced from silicon carbide. This method is commonly referred to as polymer infiltration and pyrolysis (PIP). Combinations of these three techniques can also be used.

[0032] In one example of the MI CMC process, a boron nitride-based coating system is deposited on SiC fibers. The coated fibers are then impregnated with a matrix precursor material to form a prepreg tape. One method of manufacturing the tape is filament winding. The fibers are pulled through a bath of matrix precursor slurry and the impregnated fibers are wound onto a drum. The matrix precursor may contain silicon carbide and / or carbon particles as well as organic materials. The impregnated fibers are then cut along the axis of the drum and removed from the drum to produce a flat prepreg tape in which the fibers are nominally extended in the same direction. The resulting material is a unidirectional prepreg tape. The prepreg tape can also be manufactured using a continuous prepreg machine or by other means. The tape can then be cut into shapes, laid out, and laminated to form a preform. The preform is pyrolyzed or burned off to char any organic materials in the matrix precursor and create pores. Molten silicon then permeates into the porous preform, where it can react with carbon to form silicon carbide. Ideally, excess free silicon fills any remaining pores and yields a dense composite. Matrix produced in this way typically contains residual free silicon.

[0033] The prepreg MI process produces a material with a two-dimensional fiber architecture by stacking multiple one-dimensional prepreg layers together, where the fiber orientation varies between layers. Layers are typically identified based on the orientation of continuous fibers. A zero-degree orientation is established, and other layers are designed according to the angle of their fibers relative to the zero-degree direction. Layers where fibers extend perpendicular to the zero-degree direction are called 90-degree layers, cross layers, or transverse layers.

[0034] The MI method can also be used with two-dimensional or three-dimensional braided structures. An example of this method is a slurry casting process, where fibers are first woven into a three-dimensional preform or a two-dimensional fabric. If it is fabric, layers of fabric are cut into shapes and stacked to form the preform. Chemical vapor infiltration (CVI) technology is used to deposit an interfacial coating (typically boron nitride-based or carbon-based) onto the fibers. CVI can also be used to deposit a silicon carbide matrix layer. The remainder of the matrix is ​​formed by casting a matrix precursor slurry into the preform and then immersing it in molten silicon.

[0035] An alternative to the MI method is to use CVI technology to densify the silicon carbide matrix in a one-dimensional, two-dimensional, or three-dimensional architecture. Similarly, PIP can be used to densify the matrix of the composite. Matrix generated by both CVI and PIP can be produced without excessive free silicon. Combinations of MI, CVI, and PIP can also be used to densify the matrix.

[0036] Component 10, particularly nozzle segment 12, comprises a plurality of circumferentially spaced airfoil-shaped hollow blades, of which only one is shown and referred to herein as airfoil 14. The plurality of circumferentially spaced airfoil-shaped hollow blades are supported on an arc-shaped, segmented outer band 22 and inner band 23 (only one of each is shown) 22, which are also referred to herein as endwalls. Airfoil 14, outer band 22, and inner band 23 are arranged as a plurality of circumferentially adjacent nozzle segments 12, which together form a complete 360° assembly.

[0037] It should be noted that the construction of nozzle section 12 is for illustrative purposes only, and the principles of the invention can be applied to any turbine airfoil. As shown in the figure, Figure 1 A single nozzle segment 12 is shown, comprising a single airfoil 14 against which the flow of hot exhaust gas 16 is guided. The airfoil 14 includes a width-spaced-ahead pressure side 18 and a suction side 20 extending outward in the height or span direction between opposing nozzle endwalls or bands 22 and 23. The exemplary airfoil pressure side 18 and suction side 20 shown herein can be concave and convex, respectively. The airfoil 14 includes a leading edge 24 and a trailing edge 26 spaced-ahead in the length or chord direction at or near the leading and trailing edges 28, 30 of the airfoil 14. A chord C (not shown) is defined between the leading edge 24 and the trailing edge 26 in the cross-section of the airfoil.

[0038] Figure 2 It is along Figure 1 A cross-sectional view of component 10 taken in direction 2-2 shows one or more functional features 40 as described herein, and more specifically, one or more cooling channels 42 formed in component 10. Multiple ceramic matrix composite (CMC) layers 44 are shown (only a few are shown for clarity). The multiple functional features 40 extend in alignment with the ceramic matrix composite layers 44 (as described herein). Each functional feature 40 is in fluid communication with a cooling fluid source (as described herein) via an inlet (as described herein) and via an outlet 46 (…). Figure 1 It is in fluid communication with the outside of component 10. In an alternative embodiment, at least one of the plurality of functional features 40 may be in fluid communication with the air chamber 32 defined within the airfoil 14.

[0039] Now for reference Figure 3 Alternative embodiments of the CMC components described herein are shown. Again, note that the same reference numerals will be used to denote the same parts throughout all the figures. Figure 3 In some embodiments, component 50 is shown, such as, but not limited to, a turbine rotor section 52 including airfoil 14. Although Figure 3Turbine rotor section 52 is shown. As previously described, other suitable components according to this disclosure include, but are not limited to, combustor liners, blades, nozzle endwalls / bands, blade platforms, shrouds, or other hot gas path components. Similar to Figure 1 and 2 Component 10 and component 50 are preferably formed of ceramic matrix composite (CMC) material.

[0040] exist Figure 3 In one embodiment, the CMC component 50 includes an airfoil 14, through which the flow of hot exhaust gas 16 is guided. The airfoil 14 extends from a tip 53 to a dovetail 54. The component 50 is mounted to a turbine disk (not shown) via the dovetail 54, which extends downward from the airfoil 14 and engages a slot on the turbine disk. A platform 56 extends laterally outward from the area where the airfoil 14 engages with the dovetail 54. The component 50 includes at least one air chamber 32 extending along the interior of the airfoil 14. During operation of the power generation system, a cooling airflow (not shown) is guided through the air chamber 32 to reduce the temperature of the airfoil 14.

[0041] Component 10, more specifically airfoil 14, includes airfoil pressure side 18 and suction side 20 spaced apart along the width direction, extending outward from airfoil platform 56 along airfoil span 58 in the height or wingspan direction and towards airfoil tip 53. Similar to... Figure 1 and Figure 2 The airfoil 14, as shown in this particular embodiment, has a pressure side 18 and a suction side 20 that can be concave and convex, respectively. The airfoil 14 includes a leading edge 24 and a trailing edge 26 spaced apart along its length or chord direction at or near its front end 28 and rear end 30. It should be noted that the first edge of the airfoil 14 that contacts the incoming gas 16 is referred to herein as the leading edge 24, and the second edge that contacts the hot exhaust gas 16 as it flows through the airfoil 14 is referred to as the trailing edge 26. A chord C (not shown) is defined as the line between the leading edge 24 and the trailing edge 26 of the cross-section of the airfoil 14.

[0042] Similar to previous embodiments, component 50 includes one or more functional features (not shown), and more specifically, one or more cooling channels formed within component 50. Component 50 includes a plurality of ceramic matrix composite (CMC) layers 44, wherein a plurality of functional features 40 extend in alignment with the ceramic matrix composite layers 44. Each functional feature is in fluid communication (currently described) with an air chamber 32 defined within airfoil 14 via an inlet (currently described), and in fluid communication with the exterior of component 50 via an outlet 46. In an alternative embodiment, at least one of the plurality of functional features 40 may be in fluid communication with an alternative cooling fluid source.

[0043] Now for reference Figure 4 This shows the way through Figure 1 A schematic cross-sectional view of a portion of component 10, taken by line 4-4, shows multiple CMC layers 44. In this disclosed embodiment, one or more of the multiple CMC layers 44 have one or more functional features 40 formed therein (in... Figure 4 (Only one is shown in the figure). In an embodiment, functional feature 40 is an elongated channel that serves as a cooling manifold 60 through which a cooling fluid flow 62 (also referred to herein as fluid flow 62) passes.

[0044] During the laying of multiple CMC layers 44 and the fabrication of functional features 40 (currently described), an inlet 48 is formed for each functional feature 40. Each of the multiple functional features 40 extends through and is aligned with the CMC layer 44 from its respective inlet 48. The inlet 48 provides an input of cooling fluid flow 62.

[0045] After laying multiple CMC layers 44 and fabricating functional features 40, holes 47 are drilled, for example, through the multiple CMC layers 44 in a basic cut-layer configuration, to cut through the multiple CMC layers 44 and fluidly connect the functional features 40 to the exterior of the ceramic matrix composite component 10, thereby forming an outlet 46 for each functional feature 40 near the outer surface 11 of the ceramic matrix composite component 10. Inlets 48, functional features 40, holes 47, and outlets 46 define a cooling channel 42 through the CMC layers 44, which is sufficient to allow a cooling fluid flow 62 to pass through it.

[0046] Additionally, and optionally, one or more membrane cooling vias 70 (only one shown) may be formed, for example, by drilling through multiple CMC layers 44 to cut through the layers 44 and provide additional cooling to the component surface. Each of the one or more membrane cooling vias 70 extends from an inlet 72 flush with the inner surface 13 of the ceramic matrix composite component 10 to an outlet 74 flush with the outer surface 11 of the ceramic matrix composite component 10. A portion of pressurized air from the compressor is directed through the one or more membrane cooling vias 70 as an additional cooling fluid flow 64 entering through the inlet 72 and exiting at the outlet 74. Each of the multiple membrane cooling vias 70 forms an opening through multiple CMC layers 44, the size of which is sufficient to allow the additional cooling fluid flow 64 to flow through. In an embodiment, the multiple membrane cooling vias 70 may be staggered with functional features 40, which form cooling channels 42 with warmer air to mitigate cold spots caused by the membrane cooling vias 70. Additionally, the functional features 40 forming the cooling channels 42 may be sized sufficient to supply multiple outlets 46 (currently described). By carefully arranging the positions of the cooling channel outlet 46 and the multiple film cooling through-holes 70, the surface film temperature can be made more uniform. More specifically, the cooler film cooling supplied by the multiple film cooling through-holes 70 (shorter path) can be constructed downstream of the hotter film cooling supplied by the multiple cooling channels 42, thereby producing a more uniform overall film temperature.

[0047] In the illustrated embodiment, each of the functional features 40 and the plurality of membrane cooling vias 70 is open to and in fluid communication with the cooling fluid flow source, and extends to the exterior of the component 10. Contrary to known prior art, by forming the plurality of functional features 40 between the plurality of CMC layers 44, and more specifically, the plurality of cooling channels 42, the overall strength of the CMC layers 44 and the resulting component 10 is not diminished, and better control of local cooling rates is allowed compared to conventional cooling features. Additionally, the relatively small cooling channels (e.g., cooling channels 42) with flow paths longer than conventional membrane cooling holes (e.g., the plurality of membrane cooling vias 70) utilize more of the available heat capacity in the cooling fluid flow 62, thereby reducing flow. The placement of the plurality of functional features 40 disclosed herein, allowing the cooling fluid flow 62 to experience the region of greatest thermal gradient induced stress from the cooling source through the airfoil 14, helps to balance surface temperatures and provide a novel method of gradient / pressure relief.

[0048] exist Figure 4 In the embodiments described, the arrangement of the ceramic matrix composite layer 44, functional feature 40, cooling channel 32, inlet 48, outlet 46, and film cooling via 70 is schematic and enlarged for illustrative purposes. The size and geometry of the CMC layer and voids are not limited to... Figure 4 Those shown.

[0049] Now for reference Figure 5 It shows along Figure 1 A schematic cross-sectional view of another portion of component 10, taken by line 5-5, shows multiple CMC layers 44. In this disclosed embodiment, one or more of the multiple CMC layers 44 have one or more functional features 40 formed therein (in... Figure 5 (Two are shown in the figure). In an embodiment, one or more functional features 40 are configured as elongated channels. More specifically, in the illustrated embodiment, one or more functional features 40 include a cooling channel 42 and an isolation channel 80, the cooling channel 42 serving as a cooling manifold 60 through which cooling fluid flow 62 passes, and the isolation channel 80 not in fluid communication with the hot gas path 16.

[0050] Similar to Figure 4 In this embodiment, during the laying of multiple CMC layers 44 and the fabrication of functional features 40 (currently described), an inlet 48 is formed for each functional feature 44. Each of the multiple functional features 40 extends through and is aligned with the corresponding inlet 48 from the CMC layer 44. The inlet 48 provides an input of cooling fluid flow 62.

[0051] After laying multiple CMC layers 44 and fabricating functional features 40, for example, holes 47 are drilled through the multiple CMC layers 44 in a basic cut-layer configuration to cut through the multiple CMC layers 44, thereby forming an outlet 46 for each functional feature 40 as a cooling channel 42, and the functional feature 40 is fluidly connected to the exterior of the ceramic matrix composite component 10 via the outlet 46. Similar to... Figure 4 In this embodiment, inlet 48, functional feature 40, orifice 47, and outlet 46 define a cooling channel 42 through the CMC layer 44, which is sufficient to allow cooling fluid flow 62 to flow through it. Functional feature 40, which serves as an isolation channel 80, does not include an outlet and therefore does not provide a pathway for cooling fluid 62 to pass through it to the outside of component 10.

[0052] In this embodiment, the isolation channels 80 may be formed in different layers 44, thereby providing management of heat absorption of the cooling fluid flow 62 in the cooling channels 42. The isolation channels 80, also referred to herein as “dead” channels, may also mitigate EBC spalling / damage. More specifically, constructing the isolation channels 80 very close to the hot gas path 16 will rapidly expose them in the event of spalling. New paths will then be available for the cooling fluid flow 62, thereby reducing the temperature and extending the life of the damaged airfoil 14 until it can be replaced.

[0053] In this embodiment, one or more of the plurality of functional features 40 extend from a cooling fluid source through and align with the CMC layer 44, reaching an outlet 46 and forming a cooling channel 42 through the CMC layer 44, the cooling channel 42 being sufficient to allow a cooling fluid flow 62 to flow through it. Additionally, one or more of the plurality of functional features 40 extend from a cooling fluid source through and align with the CMC layer 44, without forming an outlet, and forming an isolation channel 80. Similar to the previous embodiment, alternatively, one or more film cooling vias 70 (only one shown) may be optionally formed, for example, by drilling through the plurality of CMC layers 44 to cut through the layers 44 and provide sufficient cooling to the airfoil surface. Each of the one or more film cooling vias 70 extends from an inlet 72 flush with the inner surface 13 of the ceramic matrix composite component 10 to an outlet 74 flush with the outer surface 11 of the ceramic matrix composite component 10. A portion of the pressurized air from the compressor is directed through one or more membrane cooling through-holes 70 as an additional cooling fluid flow 64, entering through inlet 72 and exiting at outlet 74. Each of the plurality of membrane cooling through-holes 70 forms an opening through a plurality of CMC layers 44, the opening being large enough to allow the additional cooling fluid flow 64 to flow through it. In an embodiment, the plurality of membrane cooling through-holes 70 may be staggered with functional features 40 forming cooling channels 42 and isolation channels 80 with warmer air to mitigate cold spots caused by the membrane cooling through-holes 70. As in the previous embodiments, the functional features 40 forming cooling channels 42 may be large enough to supply a plurality of outlets 46 when needed.

[0054] exist Figure 5 In the embodiments, the ceramic matrix composite layer 44, functional feature 40, cooling channel 42, outlet 46, inlet 48, isolation channel 80, membrane cooling through-hole 70, and corresponding inlet 72 and outlet 74 are schematic and have been enlarged for illustrative purposes. The size and geometry of the CMC layer and voids are not limited to... Figure 5 Those shown.

[0055] Now for reference Figure 6 , showed Figure 3 A portion of the airfoil 14 illustrates an alternative layout of one or more functional features 40, and more specifically, a cooling channel 42 is shown. As shown, functional feature 40 can be configured to have a connection to platform 56 ( Figure 3 One or more turns or bands, such as the outer band 22 of nozzle segment 12. Figure 1 ) and / or inner band 23 ( Figure 1Functional features 40 can be formed by placing curved or angled slots in layer 44, forming functional features in the multilayer, or drilling openings to intersect with pre-formed channels. Forming functional features 40 in the multilayer provides cooling channels 42 to cover more of the heat entering from the limited surfaces in platforms 56 and / or bands 22, 23. The fabrication of functional features in multilayers is discussed in Attorney General's Patent Application No. 328243-1, entitled "Ceramic Matrix Composite Component Including Cooling Channels in Multilayers and Method of Fabrication Thereof," filed concurrently by T. Dyson et al., and is incorporated herein in its entirety.

[0056] In addition, such as Figure 6 As shown, the functional feature 40 forming the cooling passage 42 is sized sufficiently to supply multiple outlets 46, thereby acting as a cooling manifold 60. More specifically, each cooling passage 42 having a single inlet 48 can be fluidly connected to multiple outlets 46.

[0057] exist Figure 6 In the embodiments described, the arrangement of functional feature 40, cooling channel 42, outlet 46, inlet 48, and membrane cooling through-hole 70 is schematic and has been enlarged for illustrative purposes. The size and geometry of the CMC layer and voids are not limited to... Figure 6 Those shown.

[0058] Figure 7 A method 100 for forming CMC components 10, 50 according to this disclosure is schematically illustrated. The CMC components 10, 50 have one or more elongated functional features 40 defined therein, and more specifically, one or more cooling channels 42 formed in layers of the CMC components. Components 10, 50 are formed using a layup technique. Method 100 includes initially forming a CMC preform comprising a matrix precursor, a plurality of ceramic reinforcing fibers, and a plurality of sacrificial fibers in step 102. Forming the CMC preform includes initially providing a plurality of ceramic matrix composite layers 44, for example, a series of layers 44 formed as a stack. Examples of materials for layers 44 include, but are not limited to, prepreg composite layers, including, for example, woven carbon fibers, adhesive materials, and coated SiC fibers, as previously described.

[0059] As previously described, the method of forming a CMC preform, more specifically step 102, includes means for defining one or more elongated functional features within layer 44, for example, by using a plurality of sacrificial fibers. The sacrificial fibers enable the formation of one or more elongated functional features 40 for enhancing the functionality of the CMC, such as one or more cooling channels 42 and / or a plurality of isolation channels 80 in the CMC preform. The use of sacrificial fibers to fabricate elongated functional features is discussed in U.S. Patent No. 10,384,981, co-assigned by D. Hall et al., entitled “Method and Related Products for Forming Ceramic Matrix Composites Using Sacrificial Fibers” (in its entirety incorporated herein by reference), and in U.S. Patent Application Attorney General No. 328251-1, filed concurrently by D. Dunn et al., entitled “Method for Forming Ceramic Matrix Composites Using Sacrificial Fibers and Non-Wetting Coatings” (in its entirety incorporated herein by reference). The geometry of the one or more elongated functional features 40 defined in the CMC preform includes any suitable geometry, including circular, arcuate, elliptical, straight, or other suitable geometries.

[0060] An additional layer 44 is configured to surround the sacrificial fibers. The preform component is placed in an autoclave and cycled to form a CMC preform comprising a matrix precursor, multiple ceramic reinforcing fibers, and multiple sacrificial fibers. The preform component is subjected to typical autoclave pressure and temperature cycles used industrially for ceramic composite materials. Autoclaving removes any residual volatiles from the layers, and the autoclaving conditions may vary depending on the layer material. After autoclaving, burn-off is performed to remove any residual material or other binders from the preform component. Burn-off is typically carried out at temperatures of approximately 426–648 °C (approximately 800–1200 °F).

[0061] After burn-out, in step 104, the preform component is placed in a vacuum furnace for densification. Densification is performed using any known densification technique, including but not limited to Silicomp, melt infiltration (MI), chemical vapor infiltration (CVI), polymer expansion pyrolysis (PIP), and oxide / oxide methods. Densification can be carried out in a vacuum furnace with a stable atmosphere at a temperature above 1200°C to allow the melt of silicon or other infiltrating materials to penetrate into the preform component. A suitable densification method is melt infiltration, in which molten matrix material is drawn into layer 44 and solidified. After densification, as shown in step 104, the densified preform component or densified body includes a plurality of sacrificial fibers disposed therein and forms at least a portion of components 10, 50.

[0062] Following densification, in step 106, one or more elongated functional features 40 are further formed by removing sacrificial fibers to leave one or more elongated channels. The removal of sacrificial fibers to form elongated channels is discussed in the commonly assigned U.S. Patent No. 10,384,981 and U.S. Patent Attorney General's File No. 328251-1 cited above.

[0063] In an alternative embodiment, as described in step 104, one or more elongated functional features 40 are further formed by removing multiple sacrificial fibers prior to densification.

[0064] In an embodiment, the internal hollow portion of each of one or more elongated functional features 40 is large enough to be open within components 10, 50, allowing coolant or other fluids to be guided through to provide cooling, and optionally isolating them from components 10, 50. In an embodiment, during the layup of the sacrificial fibers, one or more fibers are laid in such a manner as to form an inlet 48 for the input of cooling fluid. A densified matrix material formed on the ceramic matrix composite layer 44 forms a blockage opposite to the inlet, which substantially prevents the flow of coolant or other fluids, and more specifically, one or more elongated functional features 40 are formed as a closed structure at the ends opposite the inlets 48 inside components 10, 15. In an embodiment, in step 108, an opening is machined or otherwise formed in components 10, 50 to provide an outlet 46 to one or more elongated functional features 40 to allow flow through and form a cooling channel 42. In an embodiment, in step 112, the blockage is held in place to form one or more isolation channels 80. In optional step 110, one or more film cooling through-holes 70 are formed in the CMC components 10, 50 to provide additional flow of cooling fluid to the surface of the airfoil and to provide additional cooling.

[0065] Therefore, a CMC component comprising a CMC preform in which one or more functional features are formed is disclosed. By forming one or more functional features as described herein, a network of cooling channels or cooling loops is formed in the CMC layers, while limiting the strength reduction of any given layer and allowing the cooling channels to change orientation without cutting the CMC fibers. Additionally, by forming one or more functional features as described herein, a network of isolating channels can be formed in the CMC layers. As previously mentioned, the design of the cooling loops provides greater durability against decay and reduces thermal stress by distributing cooling channels throughout the CMC preform. Furthermore, the combination of cooling channels provides a more uniform temperature distribution. Additional membrane cooling vias may be required to adequately cool the surface. One or more functional features are formed in the CMC component during layup and aligned with the CMC fibers in the corresponding layers. In the simplest embodiment, one or more functional features are aligned with fibers in corresponding layers of multiple layers, with the fibers arranged in alternating orientations. In more complex arrangements, one or more functional features can form a complex network, whereby the functional features are configured to have one or more turns to connect to corresponding platforms or belts, and / or are configured to provide a single functional feature fluidly connected to multiple outlets.

[0066] Although the invention has been described with reference to one or more embodiments, those skilled in the art will understand that various changes can be made and elements can be substituted with equivalents without departing from the scope of the invention. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of the invention without departing from the essential scope of the invention. Therefore, it is intended that the invention be limited to the specific embodiments disclosed as the best mode contemplated for carrying out the invention, but that the invention encompass all embodiments falling within the scope of the appended claims.

[0067] Further aspects of the invention are provided by way of the subject matter of the following clauses:

[0068] 1. A ceramic matrix composite component comprising: a plurality of longitudinally extending ceramic matrix composite layers, the plurality of longitudinally extending ceramic matrix composite layers forming a dense body in a stacked structure; one or more elongated functional features formed in the dense body and aligned with the plurality of longitudinally extending ceramic matrix composite layers, wherein each of the one or more elongated functional features includes an inlet in fluid communication with a cooling fluid flow from a fluid source; and one or more orifices, the one or more orifices extending from at least one of the one or more elongated functional features through the plurality of longitudinally extending ceramic matrix composite layers to an outlet adjacent to an outer surface of the ceramic matrix composite component.

[0069] 2. According to any of the ceramic matrix composite components in the preceding paragraph, it further includes one or more film cooling through-holes that cut through the plurality of longitudinally extending ceramic matrix composite layers from the inner surface of the ceramic matrix composite component to an outlet adjacent to the outer surface of the ceramic matrix composite component.

[0070] 3. According to any ceramic-based composite component in the preceding paragraph, wherein at least one of the one or more elongated functional features is configured to retain a flow of cooling fluid from a fluid source within the elongated functional feature to form an isolation channel.

[0071] 4. According to any ceramic matrix composite component in the preceding paragraph, wherein the one or more elongated functional features are constructed in multiple layers of the plurality of longitudinally extending ceramic matrix composite layers.

[0072] 5. According to any ceramic matrix composite component in the preceding paragraph, wherein the one or more holes are formed by one or more of laser drilling, electrical discharge machining, cutting or machining of the ceramic matrix composite material.

[0073] 6. According to any ceramic matrix composite component in the preceding paragraph, wherein the one or more film cooling vias are formed by one or more of laser drilling, electrical discharge machining, cutting or machining of the ceramic matrix composite material.

[0074] 7. According to any of the ceramic matrix composite components in the preceding paragraph, wherein the one or more elongated functional features are formed during the laying of the plurality of longitudinally extending ceramic matrix composite layers.

[0075] 8. According to any of the ceramic-based composite components in the preceding paragraph, wherein the ceramic-based composite component is a hot gas path turbine component.

[0076] 9. According to any ceramic-based composite component in the preceding paragraph, wherein the hot gas path turbine component is selected from the group consisting of burner liner, blades, shroud, nozzle, nozzle endwall and blade platform.

[0077] 10. A ceramic matrix composite component comprising: a plurality of longitudinally extending ceramic matrix composite layers, the plurality of longitudinally extending ceramic matrix composite layers forming a dense body in a stacked structure; one or more elongated functional features formed in the dense body, wherein each of the one or more elongated functional features includes an inlet in fluid communication with a cooling fluid flow from a fluid source; and one or more orifices, the one or more orifices cutting through the plurality of longitudinally extending ceramic matrix composite layers from at least one of the one or more elongated functional features to an outlet adjacent to an outer surface of the ceramic matrix composite to form at least one cooling channel, wherein at least one of the one or more elongated functional features is configured to retain a fluid flow from the fluid source within the elongated functional feature to form an isolation channel.

[0078] 11. According to any ceramic matrix composite component in the preceding paragraph, it further includes one or more film cooling through-holes that cut through the plurality of longitudinally extending ceramic matrix composite layers from the inner surface of the ceramic matrix composite component to an outlet adjacent to the outer surface of the ceramic matrix composite component.

[0079] 12. According to any ceramic matrix composite component in the preceding paragraph, wherein the one or more holes are formed by one or more of laser drilling, electrical discharge machining, cutting or machining of the ceramic matrix composite material.

[0080] 13. According to any ceramic matrix composite component in the preceding paragraph, wherein the one or more functional features are formed during the laying of the plurality of longitudinally extending ceramic matrix composite layers.

[0081] 14. According to any of the ceramic-based composite components in the preceding paragraph, wherein the ceramic-based composite component is a hot gas path turbine component.

[0082] 15. According to any ceramic-based composite component in the preceding paragraph, wherein the hot gas path turbine component is selected from the group consisting of combustion chamber lining, blades, shrouds, nozzles, nozzle endwalls, and blade platforms.

[0083] 16. A method of forming a ceramic matrix composite (CMC) product, comprising: forming a CMC preform, the CMC preform including a matrix precursor, a plurality of reinforcing fibers and a plurality of sacrificial fibers; performing one of the following operations: removing the plurality of sacrificial fibers such that one or more elongated functional features in the CMC preform are formed in communication with a source fluid flow of a cooling fluid; or applying a fluid penetrant to the CMC preform to densify the CMC preform and define a plurality of longitudinally extending ceramic matrix composite layers; and performing another of the following operations: removing the plurality of sacrificial fibers such that one or more elongated functional features are formed in the CMC preform in communication with a source fluid flow of a cooling fluid; or applying a fluid penetrant to the CMC preform to densify the CMC preform and define a plurality of longitudinally extending ceramic matrix composite layers. One or more elongated functional features are formed in the CMC preform to communicate with a source fluid flow of cooling fluid; or a fluid penetrant is applied to the CMC preform to densify the CMC preform and define a plurality of longitudinally extending ceramic matrix composite layers, and one or more holes are formed, the one or more holes cutting through the plurality of longitudinally extending ceramic matrix composite layers from at least one of the one or more elongated functional features to an outlet adjacent to the outer surface of the ceramic matrix composite component to provide fluid flow from the fluid source to the exterior of the ceramic matrix composite component and to form one or more cooling channels.

[0084] 17. According to any method in the preceding paragraph, wherein at least one of the one or more elongated functional features is configured to retain the fluid flow from the fluid source within the elongated functional feature to form an isolation channel.

[0085] 18. The method according to any of the preceding paragraph further includes forming one or more film cooling through-holes, the one or more film cooling through-holes cutting through the plurality of longitudinally extending ceramic matrix composite layers from an inlet near the inner surface of the ceramic matrix composite component to an outlet near the outer surface of the ceramic matrix composite component.

[0086] 19. According to any of the methods in the preceding paragraph, wherein the ceramic-based composite component is a hot gas path turbine component.

[0087] 20. According to any method in the preceding paragraph, wherein the hot gas path turbine components are selected from the group consisting of liner, blades, shroud, nozzle, burner, nozzle endwall and blade platform.

Claims

1. A ceramic matrix composite part (10, 50) characterized by, comprising: a plurality of longitudinally extending ceramic matrix composite layers (44) formed in a stack to form a dense body; one or more elongated functional features (40) formed in the dense body and aligned with the plurality of longitudinally extending ceramic matrix composite layers (44), wherein each of the one or more elongated functional features (40) includes an inlet (48) in fluid communication with a cooling fluid flow (62) from a fluid source; one or more holes (47) through the plurality of longitudinally extending ceramic matrix composite layers (44) from at least one of the one or more elongated functional features (40) to an outlet (46) adjacent an outer surface (11) of the ceramic matrix composite component (10, 50); and one or more film cooling vias (70) through the plurality of longitudinally extending ceramic matrix composite layers (44) from an inner surface of the ceramic matrix composite component (10, 50) to the outlet (46) adjacent the outer surface (11) of the ceramic matrix composite component (10, 50), wherein the one or more film cooling vias (70) are interleaved with the one or more elongated functional features (40) to mitigate cold spots caused by the one or more film cooling vias (70), wherein at least one of the one or more elongated functional features (40) is configured to retain the cooling fluid flow (62) from the fluid source in the elongated functional feature (40) to form at least one isolated channel (80).

2. The ceramic matrix composite part (10, 50) of claim 1, characterized in that wherein, the at least one isolated channel (80) does not include an outlet (46) adjacent the outer surface (11) of the ceramic matrix composite component (10, 50).

3. The ceramic matrix composite part (10, 50) of claim 1, wherein, wherein, each of the one or more elongated functional features (40) extends in a lengthwise direction defined by the ceramic matrix composite component (10, 50).

4. The ceramic matrix composite part (10, 50) of claim 1, wherein, wherein, the one or more elongated functional features (40) are configured in a plurality of the plurality of longitudinally extending ceramic matrix composite layers (44).

5. The ceramic matrix composite part (10, 50) of claim 1, wherein, wherein, the one or more elongated functional features (40) are formed during layup of the plurality of longitudinally extending ceramic matrix composite layers (44).

6. The ceramic matrix composite part (10, 50) of claim 1, wherein, wherein, the ceramic matrix composite component (10, 50) is a hot gas path turbine component for a gas turbine engine defining a hot gas path flow (16), wherein the isolated channel (80) is not in fluid communication with the hot gas path flow (16).

7. A method (100) of forming a ceramic matrix composite (CMC) component (10, 50), characterized by, comprising: (102) forming a CMC preform including a matrix precursor, a plurality of reinforcing fibers, and a plurality of sacrificial fibers; performing one of: (106) removing the plurality of sacrificial fibers such that one or more elongated functional features (40) in fluid communication with a source of a cooling fluid flow are formed in the CMC preform; or (108) removing the plurality of sacrificial fibers such that one or more elongated functional features (40) in fluid communication with a source of a cooling fluid flow are formed in the CMC preform. (104) applying a fluid infiltrant to the CMC preform, thereby densifying the CMC preform and defining a plurality of longitudinally extending ceramic matrix composite layers, performing another of the following: (106) removing the plurality of sacrificial fibers, such that one or more elongated functional features in fluid communication with a source of a cooling fluid flow are formed in the CMC preform; or (104) applying a fluid infiltrant to the CMC preform, thereby densifying the CMC preform and defining a plurality of longitudinally extending ceramic matrix composite layers, and (108) forming one or more holes (47) through the plurality of longitudinally extending ceramic matrix composite layers (44) from at least one of the one or more elongated functional features (40) to an exit (46) proximate an outer surface (11) of the ceramic matrix composite component (10, 50) to provide fluid flow (62) from the source of the cooling fluid flow to an exterior of the ceramic matrix composite component (10, 50) and form one or more cooling channels (42), forming one or more film cooling vias (70) through the plurality of longitudinally extending ceramic matrix composite layers (44) from an entrance proximate an inner surface of the ceramic matrix composite component (10, 50) to the exit (46) proximate the outer surface (11) of the ceramic matrix composite component (10, 50), wherein the one or more film cooling vias (70) are interleaved with the one or more elongated functional features (40) to mitigate cold spots caused by the one or more film cooling vias (70), wherein at least one of the one or more elongated functional features (40) is configured to retain the fluid flow (62) from the source of the cooling fluid flow in the elongated functional feature (40) to form at least one isolated channel (80).

8. The method (100) according to claim 7, characterized by wherein, the at least one isolated channel (80) does not include an exit (46) proximate the outer surface (11) of the ceramic matrix composite component (10, 50).

9. The method (100) according to claim 7, characterized by wherein, each of the one or more elongated functional features (40) extends in a lengthwise direction defined by the ceramic matrix composite component (10, 50).

10. The method (100) according to claim 7, characterized in that wherein, the ceramic matrix composite component (10, 50) is a hot gas path turbine component for a gas turbine engine defining a hot gas path flow (16), wherein the isolated channel (80) is not in fluid communication with the hot gas path flow (16).

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