Patent Publication Number: US-2023151740-A1

Title: Cmc component with integral cooling channels and method of manufacture

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. application Ser. No. 16/785,161, filed Feb. 7, 2020, for “CMC COMPONENT WITH INTEGRAL COOLING CHANNELS AND METHOD OF MANUFACTURE” by T. Clark, D. Whitney, K. Read, A. Lazur, and W. Barker, which claims the benefit of U.S. Provisional Application No. 62/803,327 filed Feb. 8, 2019, for “CMC BOAS WITH INTEGRAL COOLING CHANNELS AND METHOD OF MANUFACTURE” by T. Clark, D. Whitney, K. Read, A. Lazur, and W. Barker. 
    
    
     BACKGROUND 
     The present disclosure relates generally to the manufacture of components for a gas turbine engine and more particularly to the manufacture of ceramic matrix composites (CMC) with integral cooling channels. 
     Lightweight CMC is a highly desirable material for gas turbine engine applications. CMCs exhibit excellent physical, chemical, and mechanical properties at high temperatures, making CMCs particularly desirable for producing hot section components, including blade outer air seals (BOAS). Designing a CMC BOAS capable of meeting a sufficient balance of strength and thermal gradient targets has been challenging in regions where both the maximum CMC interface temperature and bulk proportional stress targets are violated. 
     A need exists to produce a CMC BOAS with a relatively low through-wall thermal gradient while providing large cross-sectional moments of inertia to react to high pressure loads. 
     SUMMARY 
     In one aspect, a fiber-reinforced component for use in a gas turbine engine includes a first braided fiber sleeve forming a cooling channel and a plurality of fiber plies enclosing the first braided fiber sleeve, with the plurality of fiber plies forming first and second walls separated by the first braided fiber sleeve. The fiber-reinforced component further includes a matrix material between fibers of the braided fiber sleeve and the plurality of fiber plies. 
     In another aspect, a method for manufacturing a fiber-reinforced component with integral fiber-formed cooling channels for use in a gas turbine engine includes forming a first braided fiber sleeve, consolidating the sleeve to form a cooling channel of a desired shape, enclosing the sleeve with a plurality of fiber plies to form a fiber preform of a component with internal cooling provided by the cooling channel, and densifying the fiber preform. 
     The present summary is provided only by way of example, and not limitation. Other aspects of the present disclosure will be appreciated in view of the entirety of the present disclosure, including the entire text, claims and accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a quarter-sectional view of a gas turbine engine. 
         FIG.  2    is a schematic view of a portion of the gas turbine engine with a blade outer air seal (BOAS). 
         FIG.  3    is a schematicized sectional view of a BOAS fiber preform with cooling channels. 
         FIG.  4    is a schematicized sectional view of an alternative BOAS fiber preform with cooling channels. 
         FIG.  5    is a schematicized sectional view of a cooling channel of  FIGS.  1  and  2    in different stages of the manufacturing process. 
         FIG.  6    is a flow chart of a method of manufacture of a BOAS using the BOAS fiber preforms of  FIGS.  3  and  4   . 
     
    
    
     While the above-identified figures set forth embodiments of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features, steps and/or components not specifically shown in the drawings. 
     DETAILED DESCRIPTION 
     The present disclosure provides a method of manufacturing a CMC component, and specifically a BOAS, with integral cooling channels constructed of CMC braided sleeves. The channels enable large film cooling access across the gas path face of the BOAS and reduce through-wall thermal gradients along the BOAS inner diameter wall. The use of CMC braided sleeves provides for seamless channel construction and can increase the specific stiffness of the BOAS, provide an efficient distribution of load, and provide resistance to crack propagation. Although the present disclosure is directed to cooling channels formed from braided fiber sleeves, woven and knit fiber tubes are also contemplated and it should be understood by one of ordinary skill in the art that woven and knit fiber tubes can replace the braided fiber sleeves in the disclosed embodiments. Although the present disclosure is directed to cooling channels formed in a BOAS, the disclosed method can be used to form other components including but not limited to components of a hot section of a gas turbine engine, such as turbine blades, vanes, and platforms; combustors; and exhaust nozzles or mixers. 
       FIG.  1    is a quarter-sectional view of a gas turbine engine  20  that includes fan section  22 , compressor section  24 , combustor section  26  and turbine section  28 . Fan section  22  drives air along bypass flow path B while compressor section  24  draws air in along core flow path C where air is compressed and communicated to combustor section  26 . In combustor section  26 , air is mixed with fuel and ignited to generate a high pressure exhaust gas stream that expands through turbine section  28  where energy is extracted and utilized to drive fan section  22  and compressor section  24 . 
     Although the disclosed non-limiting embodiment depicts a turbofan gas turbine engine, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines; for example a low-bypass turbine engine, or a turbine engine including a three-spool architecture in which three spools concentrically rotate about a common axis and where a low spool enables a low pressure turbine to drive a fan via a gearbox, an intermediate spool that enables an intermediate pressure turbine to drive a first compressor of the compressor section, and a high spool that enables a high pressure turbine to drive a high pressure compressor of the compressor section. 
     The example engine  20  generally includes low speed spool  30  and high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided. 
     Low speed spool  30  generally includes inner shaft  40  that connects fan  42  and low pressure (or first) compressor section  44  to low pressure (or first) turbine section  46 . Inner shaft  40  drives fan  42  through a speed change device, such as geared architecture  48 , to drive fan  42  at a lower speed than low speed spool  30 . High-speed spool  32  includes outer shaft  50  that interconnects high pressure (or second) compressor section  52  and high pressure (or second) turbine section  54 . Inner shaft  40  and outer shaft  50  are concentric and rotate via bearing systems  38  about engine central longitudinal axis A. 
     Combustor  56  is arranged between high pressure compressor  52  and high pressure turbine  54 . In one example, high pressure turbine  54  includes at least two stages to provide a double stage high pressure turbine  54 . In another example, high pressure turbine  54  includes only a single stage. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine. 
     The example low pressure turbine  46  has a pressure ratio that is greater than about 5. The pressure ratio of the example low pressure turbine  46  is measured prior to an inlet of low pressure turbine  46  as related to the pressure measured at the outlet of low pressure turbine  46  prior to an exhaust nozzle. 
     Mid-turbine frame  58  of engine static structure  36  is arranged generally between high pressure turbine  54  and low pressure turbine  46 . Mid-turbine frame  58  further supports bearing systems  38  in turbine section  28  as well as setting airflow entering low pressure turbine  46 . 
     The core airflow C is compressed by low pressure compressor  44  then by high pressure compressor  52  mixed with fuel and ignited in combustor  56  to produce high speed exhaust gases that are then expanded through high pressure turbine  54  and low pressure turbine  46 . Mid-turbine frame  58  includes airfoils/vanes  60 , which are in the core airflow path and function as an inlet guide vane for low pressure turbine  46 . Utilizing vanes  60  of mid-turbine frame  58  as inlet guide vanes for low pressure turbine  46  decreases the length of low pressure turbine  46  without increasing the axial length of mid-turbine frame  58 . Reducing or eliminating the number of vanes in low pressure turbine  46  shortens the axial length of turbine section  28 . Thus, the compactness of gas turbine engine  20  is increased and a higher power density may be achieved. 
     Each of the compressor section  24  and the turbine section  28  can include alternating rows of rotor assemblies and vane assemblies (shown schematically) that carry airfoils that extend into the core flow path C. To improve efficiency, static outer shroud seals (not shown), such as a BOAS, can be located radially outward from rotor airfoils to reduce tip clearance and losses due to tip leakage. 
       FIG.  2    illustrates a portion of a gas turbine engine, such as, but not limited to, gas turbine engine  20  of  FIG.  1   , having BOAS  70 . The portion of the gas turbine engine illustrated in  FIG.  2    is intended to be non-limiting. The portion of the gas turbine engine illustrated in  FIG.  2    has stator assemblies  72  and  74 , and rotor  76 . Stator assemblies  72  and  74  can each have a plurality of airfoils  80  and  82 , respectively, to direct core airflow C. Rotor  76  can have a plurality of airfoils  84  to create or extract energy from core airflow. BOAS  70  can be configured to reduce core airflow leakage across rotor tip  86 . BOAS  70  can be located radially inward of an annular case (not shown) and radially outward of rotor tip  86 . Conventionally, a plurality of segmented BOAS  70  can be used, collectively forming a ring around rotor  76  to seal multiple airfoils  84 . BOAS  70  can be mounted to an annular ring or segmented seal carrier (not shown) or directly to the case as known in the art. 
       FIGS.  3  and  4    provide schematicized sectional views of alternative embodiments of a fiber preform  88  and  88 ′ used for the manufacture of BOAS  70 . Preforms  88  and  88 ′ are intended to provide non-limiting examples of a geometry of BOAS  70 . It will be understood by those of ordinary skill in the art that the geometry of BOAS  70 , including the number and orientation of cooling channels can be varied as needed to meet thermal and mechanical stress requirements. Some of the possible alternative configurations are described herein although not illustrated. In some embodiments, a thermal barrier coating, environmental barrier coating, and/or abradable coating can be provided on a surface of BOAS  70 . Thermal barrier coatings and environmental barrier coatings can protect the CMC component from degradation. Abradable coatings can be applied in a blade rub zone to maintain close clearances thereby improving turbine efficiency. 
       FIG.  3    illustrates fiber preform  88 , which includes cooling channels  90   a - 90   c  fed by a source of cooling fluid through inlet apertures  92   a - 92   c . As illustrated, cooling channels  90   a - 90   c  can extend in a circumferential direction relative to engine axis A. Preform  88  has three cooling channels  90   a ,  90   b ,  90   c  located adjacent one another and configured to cover an axial extent of BOAS  70 , extending from a leading edge LE to a trailing edge TE. While positioning cooling channels along a full axial extend of BOAS  70  can provide cooling fully along a radially inner wall positioned in the gas path, alternative configurations, which do not provide cooling along the full axial extent of BOAS  70 , are also contemplated. 
     As illustrated in  FIG.  3   , a cooling fluid flow C f  can be fed to leading edge cooling channel  90   a  through a pair of apertures  92   a . Cooling channel  90   a  can be substantially closed at an intersegment side  93  of BOAS  70  adjacent to apertures  92   a  to direct cooling fluid flow C f  through cooling channel  90   a  as indicated by the C f  arrow. In some embodiments, an adjacent BOAS  70  can be configured to allow flow exiting cooling channel  90   a  from an outlet at an opposite intersegment side  94  to enter a cooling fluid channel in the adjacent BOAS. In other embodiments, cooling channel  90   a  can be substantially closed at intersegment outlet  94  and cooling fluid flow C f  can be forced to exit through a plurality of intersegment gas path-facing film cooling apertures (not shown) as known in the art. Cooling fluid C f  can enter cooling channel  90   b  through a pair of apertures  92   b . Cooling channel  92   b  can be substantially closed (not shown) at intersegment side  94  to direct cooling fluid flow C f  in a circumferential direction as illustrated by the C f  arrow. In some embodiments, cooling channel  90   b  can be fluidly connected to cooling channel  90   c  to allow cooling fluid flow C f  exiting cooling channel  90   b  at intersegment side  93  to enter cooling channel  90   b  at intersegment side  93  and flow back toward intersegment side  94  as illustrated by the C f  arrow. Cooling channels  90   b  and  90   c  can be substantially closed (not shown) at intersegment side  93  to limit cooling fluid flow C f  exiting BOAS  70  at intersegment side  93 , while allowing cooling fluid C f  to pass from cooling channel  90   b  to cooling channel  90   c . In alternative embodiments, cooling channel  90   c  can be fluidly separated from cooling fluid channel  90   b  and cooling fluid can be fed to cooling channel  90   c  through optional apertures  92   c  (shown in phantom). Intersegment side or wall members (not shown) used to close or restrict cooling channels  90   a - 90   c  can be formed separately and joined to preform  88  following densification of fiber preform  88  via brazing or other suitable methods known in the art. Cooling fluid C f  can exit cooling fluid channels  90   b  and  90   c  through intersegment or gas path-facing film cooling apertures. In some embodiments, one or both cooling channels  90   b ,  90   c  can be open at intersegment sides  93  or  94  to allow cooling fluid C f  to enter cooling channels of adjacent BOAS as described with respect to cooling channel  90   a . The internal cooling channels can function to actively cool BOAS  70  during operation to reduce bulk temperature, or to passively cool BOAS  70  to reduce through wall thermal gradients. Internal cooling channels can enable intersegment cooling via cooling holes directed between adjacent BOAS segments, as well as film cooling along a radially inner face of BOAS  70  exposed to the hot gas path. Although  FIG.  3    illustrates three cooling channels  90   a - 90   c , it should be appreciated that the number of cooling channels and fluid interconnection of cooling channels can be varied based on cooling needs, and that any number of cooling channels can be contemplated. In the disclosed BOAS, cooling channels configured to extend circumferentially (as illustrated) can generally range in number from two to six. The number of cooling fluid feed apertures  92   a - 92   c  can vary accordingly. Additionally, the location and number of feed apertures for each cooling channel can be varied as needed to maintain pressure requirements. In alternative embodiments, a single serpentine cooling channel may be used or walls of a braided sleeve may be compressed together to form multiple cooling channels. In some embodiments, a component could have spiral cooling channels originating at one or more center points and exiting at a rear of the component. Braided fiber sleeves can have a constant or variable cross-section to form cooling channels that are tapered in thickness and/or width. By varying the cross-section of fiber bundles within the braid (and weave or knit), cooling channels can be created with internal roughness that enhances heat transfer, which can provide significant advantage. Additionally, in braided fiber sleeves, it is possible to also introduce fibers only in one rotating direction to create swirling of air. 
     BOAS fiber preform  88  is formed from a plurality of braided fiber sleeves  96  (i.e., tubular braid with seamless fiber continuity from end to end), which are enclosed or wrapped in one or more layered woven or braided fiber plies  98 . Suitable materials used to make braided fiber sleeves  96  and fiber plies  98  can include, but are not limited to carbon, silicon carbide (SiC), alloyed and/or zirconium carbide, hafnium carbide, aluminum silicate, alumina, and other materials known in the art for use in various environmental conditions, including varying operational temperatures. Fibers can be impregnated with a SiC matrix and various binders. Interface coatings, such as boron nitride, can be applied to the fibers before or after a layup process to protect fibers from oxidation during operation. 
     Cooling channels  90   a - 90   c  of fiber preform  88  are formed from braided fiber sleeves  96 . Braided fiber sleeves offer multiple advantages over woven or unidirectional fiber plies. Braided fiber sleeves  96  have continuous fibers that are mechanically interlocked with one another providing for an efficient distribution of load and resistance to impact and crack propagation. Interlaminar shear properties are improved when braided fiber sleeves are nested together, which can further limit crack propagation. Braided fiber sleeves can expand to accommodate irregular cross-sections and can form irregular shapes. Because fibers are braided on the bias, there is a reduced tendency for fiber breakage when forced to accommodate a small radius. Braided fiber sleeves  96  can be formed from a biaxial braid or a triaxial braid, which provides reinforcement in the axial direction. The angles of the fibers of the braid can be tailored to balance the stresses better than is possible with a 0/90 woven fabric, which makes the braid structurally more efficient than a woven fabric for cooling channels that are required to hold cooling fluid at a higher pressure than the working fluid in the engine core gas path. 
     Each of cooling channels  90   a - 90   c  is defined by a braided fiber sleeve comprising nested fiber braids aligned concurrently to form inner wall  100  and outer wall  102 . As illustrated in  FIG.  3   , braided fiber sleeves  96  can be consolidated to form an oblong shape with radiused ends  104  separated by elongated sides  105 . A length of elongated sides  105  can vary depending on the number cooling channels present. In the embodiment disclosed in  FIG.  3   , a cross-section of cooling channels  90   a - 90   c  has an aspect ratio of approximately 8:1. In alternative embodiments, cooling channels  90   a - 90   c  can be substantially cylindrical, having a circular cross-section. Bending constraints of braided fiber sleeves  96  generally limit radiused ends to a minimum radius around 0.25 millimeters, providing a cooling channel height h of 0.5 millimeters. In the embodiment disclosed in  FIG.  3   , cooling channels  90   a - 90   c  can have a channel height ranging from 0.5 to 2 millimeters, and radii of radiused ends  104  ranging from 0.25 to 1 millimeters. 
     Fiber plies  98  can encase cooling channels  90   a - 90   c  thereby forming inner radial wall  106  facing the engine gas path and outer radial wall  108 . Plies can generally have a thickness ranging from 0.005″ to 0.015″. It should be appreciated that the number of plies or layers forming each of walls  106  and  108  can vary depending on ply thickness and structural requirements. Fiber plies  98  can be formed from separate fiber sheets, which can be a woven or braided fabric. Fiber plies  98  can be wrapped to extend from attachment mechanisms  110  and  112  underneath cooling channels  90   a - 90   c  to provide additional support. It should be appreciated that alternative fiber ply layup configurations are contemplated and that the design can be modified accordingly to accommodate varying structural requirements. Gaps between plies or locations where plies are absent can be filled with small braids or chopped fibers. 
       FIG.  4    is a schematicized sectional view of an alternative fiber preform  88 ′ for the manufacture of BOAS  70 . Preform  88 ′ is similar to preform  88  but includes a braided fiber overwrap  114 . Braided fiber overwrap  114  can replace a portion or all of fiber plies  98  and can be formed from one or more braided fibers sleeves. Braided fiber overwrap  114  can fully wrap around braided fiber sleeves  96  to form BOAS walls  106  and  108 . Braided fiber overwrap  114  can be shaped to provide attachment mechanisms  110 ′ and  112 ′. The use of braided fiber overwrap  114  provides a seamless fiber preform structure, providing added strength and resistance to crack formation. 
       FIG.  5    is a schematicized sectional view of cooling channel  90   a  at different stages in the manufacturing process. Cooling channel  90   a  (as well as all other cooling channels disclosed) can be formed by braiding fiber sleeve  96  on a mandrel to produce a cylindrical tube as illustrated by step  1  in the process. In step  2 , braided fiber sleeve  96  can be consolidated to a desired aspect ratio or to provide a desired cooling channel height. In alternative embodiments, cooling channel  90   a  can be formed by braided fiber sleeve  96  on a mandrel more closely matched to the desired shape of cooling channel  90   a , such that limited or no compression of braided sleeve  96  is necessary. This can limit an amount of buckling of inner wall  100  that can occur during shaping. 
     Plies  98  or braided sleeves  114  can be laid up around multiple consolidated braided fiber sleeves  96  to form preform  88  or  88 ′ with cooling channels  90   a - 90   c . In some embodiments, braided fiber sleeves  96  can be placed on mandrels capable of maintaining cooling channels  90   a - 90   c  during CVI or other densification process and capable of being extracted in post processing. In alternative embodiments, braided fiber sleeves  96  can be separately densified—partially or fully—before layup with fiber plies  98  or braided fiber sleeves  114 . As such, use of additional tooling to maintain cooling channels  90   a - 90   c  can be avoided during densification of fiber preform  88  or  88 ′. This may allow for the addition of intersegment walls or other structures that could have limited extraction of tooling post densification. Hoop oriented fibers (low braid angle or woven 0/90 tubes) can provide reasonable resistance to compression and, therefore, support for subsequent processing without internal tooling. This results in significant additional design space for optimization of cooling channels without the constraint of mandrel removal. 
       FIG.  6    is a flow chart of method  120  of manufacture of BOAS  70  using preforms  88  and  88 ′ of  FIGS.  3  and  4   . A plurality of braided fiber sleeves  96  can be formed on a graphite mandrel or other removable tooling (e.g., dissolvable or removed via vaporization/sublimation) in step  122  and consolidated in step  124  to provide a desired shape of cooling channels  90   a - 90   c . Alternatively, cooling channels  90   a - 90   c  can be tapered slightly from intersegment ends  93  to  94  to allow for mechanical extraction of a graphite mandrel following densification. In some embodiments, braided fiber sleeves  96  can be densified via CVI or other process in step  126  to produce rigid structures that can be maintained during densification of preform  88  or  88 ′ without the need for a temporary mandrel. In step  128 , the plurality of braided fiber sleeves  96  can be enclosed in a plurality of fiber plies  98  or braided fiber sleeves  114  to produce preform  88  or  88 ′, respectively. Fiber preform  88  or  88 ′ can be densified with a ceramic matrix in step  130  using CVI, precursor infiltration and pyrolysis, slurry infiltration, melt infiltration, and combinations thereof as known in the art. Any tooling used to maintain cooling channels  90   a - 90   c  during densification can be removed in step  140 . Additional processing or finishing procedures as known in the art can be performed, including deposition of a thermal barrier or environmental barrier coating. Apertures  92   a  and  92   b  can be ultrasonically machined through wall  108  of BOAS  70  to provide a conduit for cooling fluid C f  into cooling channels  90   a - 90   c.    
     The integral cooling channels constructed of CMC braided sleeves enable large film cooling access across the gas path face of the BOAS and reduce through-wall thermal gradients along the BOAS inner diameter wall. The use of CMC braided sleeves provides for seamless channel construction and can increase the specific stiffness of the BOAS, provide an efficient distribution of load, and provide resistance to crack propagation. 
     Summation 
     Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, transient alignment or shape variations induced by thermal, rotational or vibrational operational conditions, and the like. Moreover, any relative terms or terms of degree used herein should be interpreted to encompass a range that expressly includes the designated quality, characteristic, parameter or value, without variation, as if no qualifying relative term or term of degree were utilized in the given disclosure or recitation. 
     Discussion of Possible Embodiments 
     The following are non-exclusive descriptions of possible embodiments of the present invention. 
     A fiber-reinforced component for use in a gas turbine engine according to an exemplary embodiment includes, among other possible things, a first braided fiber sleeve forming a cooling channel and a plurality of fiber plies enclosing the first braided fiber sleeve, with the plurality of fiber plies forming first and second walls separated by the first braided fiber sleeve. The fiber-reinforced component further includes a matrix material between fibers of the braided fiber sleeve and the plurality of fiber plies. 
     The fiber-reinforced component of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
     The fiber-reinforced component of the preceding paragraph can further include an aperture extending through the first wall into the cooling channel to provide cooling fluid to the cooling channel. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein at least one of the plurality of fiber plies can be formed from a second braided fiber sleeve. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the second braided fiber sleeve can form an outermost fiber layer of the component. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the component can include a plurality of cooling channels formed from a plurality of braided fiber sleeves including the first braided fiber sleeve, wherein the plurality of braided fiber sleeves is enclosed by the plurality of fiber plies. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the plurality of braided fiber sleeves can have a compressed shape with radiused sides separated by elongated sides forming a cooling channel with a height ranging from 0.5 to 2 millimeters (20 to 80 thousandths of an inch). 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the plurality of braided fiber sleeves can have a compressed shape with radiused sides having a radius ranging from 0.25 millimeters to 1 millimeter. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the component can be a blade outer air seal (BOAS) and wherein the plurality of cooling channels can extend in a circumferential direction relative to an engine axis. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the plurality of braided fiber sleeves and the plurality of fiber plies can comprise materials selected from the group consisting of: carbon fibers and ceramic fibers. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the plurality of braided fiber sleeves can comprise a triaxial braid. 
     The fiber-reinforced component of any of the preceding paragraphs, wherein each of the plurality of braided fiber sleeves forming the plurality of cooling channels can be formed from nested braided fiber sleeves, which form an outer diameter wall and an inner diameter wall, 
     The fiber-reinforced component of any of the preceding paragraphs, wherein the matrix material can comprise a ceramic. 
     A method for manufacturing a fiber-reinforced component with integral fiber-formed cooling channels for use in a gas turbine engine according to an exemplary embodiment includes, among other possible things, forming a first braided fiber sleeve, consolidating the sleeve to form a cooling channel of a desired shape, enclosing the sleeve with a plurality of fiber plies to form a fiber preform of a component with internal cooling provided by the cooling channel, and densifying the fiber preform. 
     The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, additional components, and/or steps: 
     The method of the preceding paragraphs can further include densifying the first braided fiber sleeve prior to enclosing the first braided fiber sleeve with a plurality of fiber plies. 
     The method of any of the preceding paragraphs can further include forming the cooling channel by placing the first braided fiber sleeve on tooling and removing the tooling during or subsequent to densifying the fiber preform. 
     The method of any of the preceding paragraphs can further include forming a second braided fiber sleeve, consolidating the second braided fiber sleeve to form a second cooling channel of a desired shape, positioning the second braided fiber sleeve adjacent to the first braided fiber sleeve, and enclosing the second braided fiber sleeve with the plurality of fiber plies. 
     The method of any of the preceding paragraphs, wherein the plurality of fiber plies comprises a third braided fiber sleeve. 
     The method of any of the preceding paragraphs can further include positioning the third braided fiber sleeve around the first and second braided fiber sleeves and positioning the third braided fiber sleeve to form an outermost fiber layer of the fiber preform. 
     The method of any of the preceding paragraphs, wherein the first and second fiber sleeves can be formed from nested braided fiber sleeves, which form an inner diameter wall and an outer diameter wall. 
     The method of any of the preceding paragraphs, wherein the first and second braided fiber sleeves can comprise a triaxial braid. 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.