Method and system for providing cooling for turbine components

A system for providing cooling for a turbine component that includes an outer surface exposed to combustion gases is provided. A component base includes at least one fluid supply passage coupleable to a source of cooling fluid. At least one feed passage communicates with the at least one fluid supply passage. At least one delivery channel communicates with the at least one feed passage. At least one cover layer covers the at least one feed passage and the at least one delivery channel, defining at least in part the component outer surface. At least one discharge passage extends to the outer surface. A diffuser section is defined in at least one of the at least one delivery channel and the at least one discharge passage, such that a fluid channeled through the system is diffused prior to discharge adjacent the outer surface.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to turbomachinery, and, more specifically, to methods and systems for providing a cooling system for component internal structures and component surfaces within gas turbines.

In at least some known gas turbines, in a component such as an airfoil or nozzle that is exposed to hot combustion gases, an internal structure within the component is cooled using cooling air or other fluid that is channeled through microchannels defined within the internal structure. Typically, the microchannels extend below and substantially parallel to at least a portion of an outer surface of the component. Cooling air is supplied to the microchannels from a cooling air supply passage that is also defined within the component and coupled to a source of cooling air. In at least some known gas turbines, the microchannels terminate in a trench that is oriented substantially perpendicularly to the microchannels. Typically, the trench defines an elongated opening in the component outer surface. After receiving heat from the internal structure of the component, the cooling air is exhausted from the microchannels and discharged into the trench and out through the elongated opening. The discharged cooling air defines a cooling air film adjacent to the outer surface that facilitates reduction of heat transfer from the hot combustion gases through the outer surface of the component into the internal structure.

It is desirable to improve an efficiency of the microchannels to facilitate more effective transfer of heat from the internal structure of the component into the cooling air, such that a lower cooling air flow rate is required, towards facilitating an improvement of an overall efficiency of the gas turbine.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method of providing a cooling system for a turbine component that includes an outer surface that is exposed to combustion gases during turbine operation is provided. The method includes defining a component base with at least one fluid supply passage coupleable to a source of cooling fluid. The method also includes defining at least one feed passage in the component base, the at least one feed passage coupled in flow communication with the at least one fluid supply passage. The method also includes defining at least one delivery channel in the component base, the at least one delivery channel coupled in flow communication with the at least one feed passage. The method also includes defining at least one cover layer on the base to cover the at least one feed passage and the at least one delivery channel, and to define at least a portion of the component outer surface. The method also includes defining at least one discharge passage through the at least one cover layer, the at least one discharge passage coupled in flow communication with the at least one delivery channel and extends to the defined portion of the outer surface. The method also includes defining a diffuser section in at least one of the at least one delivery channel and the at least one discharge passage, such that a fluid channeled through the at least one delivery channel and the at least one discharge passage is diffused prior to discharge adjacent the defined portion of the outer surface.

In another aspect, a system for providing cooling of a turbine component that includes an outer surface that is exposed to combustion gases during turbine operation is provided. The system includes a component base that includes at least one fluid supply passage coupleable to a source of cooling fluid. The system also includes at least one feed passage defined in the component base, the at least one feed passage coupled in flow communication with the at least one fluid supply passage. The system also includes at least one delivery channel defined in the component base, the at least one delivery channel coupled in flow communication with the at least one feed passage. The method also includes at least one cover layer defined on the base to cover the at least one feed passage and the at least one delivery channel, the at least one cover layer defining at least a portion of the component outer surface. The method also includes at least one discharge passage defined through the at least one cover layer, such that the at least one discharge passage is coupled in flow communication with the at least one delivery channel and extends to the defined portion of the outer surface. The method also includes a diffuser section defined in at least one of the at least one delivery channel and the at least one discharge passage, such that a fluid channeled through the at least one delivery channel and the at least one discharge passage is diffused prior to discharge adjacent the defined portion of the outer surface.

In still another aspect, a gas turbine system is provided. The gas turbine system includes a compressor section. The gas turbine system also includes a combustion system coupled in flow communication with the compressor section. The gas turbine system also includes a turbine section coupled in flow communication with the combustion system. The turbine section includes a component base that includes at least one fluid supply passage coupleable to a source of cooling fluid. The turbine section also includes at least one feed passage defined in the component base, wherein the at least one feed passage is coupled in flow communication with the at least one fluid supply passage. The turbine section also includes at least one delivery channel defined in the component base, wherein the at least one delivery channel is coupled in flow communication with the at least one feed passage. The turbine section also includes at least one cover layer defined on the base to cover the at least one feed passage and the at least one delivery channel, wherein the at least one cover layer defines at least in part the component outer surface. The turbine section also includes at least one discharge passage defined through the at least one cover layer, wherein the at least one discharge passage is coupled in flow communication with the at least one delivery channel and extends to the outer surface. The turbine section also includes a diffuser section defined in at least one of the at least one delivery channel and the at least one discharge passage, such that a fluid channeled through the at least one delivery channel and the at least one discharge passage is diffused prior to discharge adjacent the outer surface.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the terms “axial” and “axially” refer to directions and orientations extending substantially parallel to a longitudinal axis of a gas turbine engine. Moreover, the terms “radial” and “radially” refer to directions and orientations extending substantially perpendicularly to the longitudinal axis of the gas turbine engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations extending arcuately about the longitudinal axis of the gas turbine engine. It should also be appreciated that the term “fluid” as used herein includes any medium or material that flows, including, but not limited to, gas and air. As used herein, the term “turbine component” refers to any structure within a gas turbine that may be exposed to elevated temperatures and/or to combustion gases, including, but not limited to, rotor and stator blades and related components, combustor liners, transition pieces, and fuel nozzles.

FIG. 1is a schematic illustration of an exemplary gas turbine engine100. Engine100includes a compressor assembly102and a combustor assembly104. Engine100also includes a turbine108and a common compressor/turbine shaft110(also sometimes referred to as a rotor110).

In operation, air flows through compressor assembly102such that compressed air is supplied to combustor assembly104. Fuel is channeled to a combustion region and/or zone (not shown) that is defined within combustor assembly104wherein the fuel is mixed with the air and ignited. Resulting combustion gases are channeled to turbine108wherein gas stream thermal energy is converted to mechanical rotational energy. Turbine108is rotatably coupled to rotor110, for rotation about an axis of rotation106.

FIG. 2is an enlarged schematic illustration of a portion of gas turbine engine100that includes axially spaced apart rotor disks112and spacers114that are coupled to each other, for example, by a plurality of circumferentially-spaced, axially-extending bolts116. Although bolts116are shown inFIG. 2, for facilitating coupling of disks112to spacers114, any other suitable coupling structures may be used that enable gas turbine engine100to function as described herein. Gas turbine engine100includes, for example, a plurality of first-stage nozzles118and a plurality of second-stage nozzles120. Each plurality of nozzles118and120includes a plurality of circumferentially-spaced stator vanes, such as stator vanes122and124. A plurality of first-stage rotor blades126are coupled, for example, via disk112, to rotor110(shown inFIG. 1), for rotation between nozzles118and120. In the exemplary embodiment, each rotor blade126includes an airfoil130coupled to a shank132. Similarly, a plurality of second-stage rotor blades128likewise is coupled to rotor110, for rotation between second-stage nozzles120and a third stage of nozzles (not shown). Although two stages of rotor blades126and128, and two stages of nozzles118and120, are shown and described herein, at least some known gas turbine engines include different numbers of nozzle and rotor blade stages.

Each rotor blade126is coupled to rotor disk112using any suitable coupling method that enables gas turbine engine100to function as described herein. Specifically, in the exemplary embodiment, each rotor blade126includes a dovetail134coupled to shank132. Dovetail134is insertably received axially (i.e., in a direction substantially parallel to axis of rotation106illustrated inFIG. 1) within a suitably-shaped slot136defined in rotor disk112. In an example gas turbine engine100, a flow125of hot combustion gases is channeled through rotor/stator cavity127, exposing outer surfaces129,131, and133, of stator vane122, airfoil130, stator vane124, or a shroud123, respectively, to high temperatures and potential corresponding thermal stresses and/or thermal degradation. To at least partially address such exposure, one or more of stator vane122, airfoil130, stator vane124and/or shroud123and/or any other hot component in the turbine are provided with a cooling system137that includes a cooling air supply channel coupled to subsurface microchannels (not shown), as previously described, that terminate, for example, in a discharge passage in the form of a trench139opening onto surface129of stator vane122. Although air is specifically described, in alternative embodiments a fluid other than air is used to cool components exposed to combustion gases. It should also be appreciated that the term “fluid” as used herein includes any medium or material that flows, including, but not limited to, gas, steam, and air.

FIG. 3is a top perspective view of an exemplary microchannel system200that can be used in cooling system137.FIG. 4is a side perspective view of microchannel system200. As previously described, microchannel system200is used to supply cooling air through any structure within engine100(shown inFIGS. 1 and 2) for which both internal cooling and surface film cooling are desired. Microchannel system200includes a transversely-extending distribution passage202into which cooling air is channeled from a cooling air supply channel201. Cooling air supply channel201has any suitable configuration sufficient to enable system200to function as described. In the exemplary embodiment, distribution passage202is positioned a distance C below a component surface204(shown inFIG. 4) of a component body205. Distribution passage202is coupled in flow communication to a plurality of feed passages206. In the exemplary embodiment, feed passages have a width or diameter of about 5 mils to about 120 mils, though in other embodiments, different values may be used. Each feed passage206is coupled in flow communication with a corresponding delivery channel208. In each delivery channel208, an air flow209proceeds in a direction indicated by the arrows. In the exemplary embodiment, each delivery channel208includes a section210that is configured with a substantially constant cross-sectional area along a length A, wherein the cross-sectional area is measured in a plane P extending perpendicularly to air flow209.

Section210includes a side wall213and an opposite side wall215. Each section210terminates in a diffuser section212that is configured with diverging side walls214and216(shown inFIG. 4), and substantially parallel top wall218and bottom wall220. Accordingly, diffuser section212includes an increasing cross-sectional area along a length B, wherein the cross-sectional area is measured in a plane Q extending perpendicularly to the direction of air flow209. In the exemplary embodiment, length B is equal to about 3 to about 5 times a width W of channel section210, wherein width W is from about 5 mils to about 120 mils. In other embodiments, length B is any value that enables system200to function as described.

In the exemplary embodiment, wall214diverges from side wall213and/or wall216diverges from side wall215by an angle α, wherein α ranges from about 5° to about 15°. In alternative embodiments, other angle values are used that are sufficient to enable system200to function as described. Moreover, angle α does not have to be constant along the length of walls213and/or216, but can vary. That is, one or both of walls213and/or216has one or more bends therein, or is curved. Each diffuser section212is coupled in flow communication with a discharge passage in the form of a transversely-extending trench222. Trench222includes a narrow elongated opening224in surface204.

In the exemplary embodiment, distribution passage202and feed passages206have any cross-sectional configuration, including but not limited to circular, oval, square, rectangular, or polygonal, that enables system200to function as described herein. In the embodiment ofFIGS. 3 and 4, delivery channels208(including sections210and diffuser sections212) have rectangular cross-sectional configurations. In alternative embodiments, delivery channels208have any other cross-sectional configuration that enables system200to function as described herein.

In the exemplary embodiment, microchannel system200is defined by first casting a component body205(shown inFIG. 4). Moreover, in the exemplary embodiment, air supply channel201(shown inFIG. 3) and/or distribution passage202are created during casting of component body205. During and/or casting component body205, feed passages206, and delivery channels208are defined using any suitable passage-defining method, including but not limited to cutting tool-based machining and/or milling, EDM (electrical discharge machining), water machining, laser machining, and/or any other passage-defining (for example, by material removal) method that enables microchannel system200to function as described herein. In alternative embodiments, one or more of structures206,208,212and/or222is cast-in. If one or more of structures206,208,212, and/or222is cast-in, then a region225between surface204and one or more of structures206,208, and/or212defines in part a cover layer223. In the exemplary embodiment, one or more of structures202,206,208and/or212is not cast-in, but is open at surface204. In that embodiment, after feed passages206and delivery channels208are defined in a surface204of body205, a layer217of pre-sintered preform (“PSP”) braze material is coupled to body205to cover feed passages206and delivery channels208. Thereafter, a bond coat219is coupled to PSP layer217, and a DVC (“dense vertically cracked”) coat221is coupled to bond coat219, to further cover feed passages206and delivery channels208, in addition to PSP layer217. In one alternative embodiment, a metal alloy is welded over one or more of structures206,208, and/or212, after which coats219and/or221are applied. In another alternative embodiment, coats219and/or221are directly applied over one or more of structures206,208, and/or212, using bridging techniques so that coats219and/or221do not fill structures206,208, and/or212. Although three cover layers are described herein, in alternative embodiments, any number of cover layers is used that enables system200to function as described herein. After placement of layers217,219, and221, trench222is defined using one of the passage-defining techniques previously described. In alternative embodiments, any suitable formation method for defining feed passages206, delivery channels208, and/or trench222is used that enables system200to function as described. In the exemplary embodiment, air supply channel201, distribution passage202, feed passages206, delivery channels208, and/or trench222have any suitable dimensions that enable microchannel system200to function as described herein.

In operation, as illustrated inFIG. 3, cooling air flow207is channeled from air supply channel201into distribution passage202, where flow207is divided into a plurality of flows209that are channeled through feed passages306and into delivery channels208. As flows209are discharged from sections210and enter diffuser sections212, flows209are facilitated to spread or expand as they are channeled into trench222. In trench222, flows209merge, and are discharged from trench222as a film211.

FIG. 5is a top perspective view of an alternative exemplary microchannel system300that can be used in cooling system137. Microchannel system300is used to supply cooling air through any structure within engine100(shown inFIGS. 1 and 2) for which both internal cooling and surface film cooling are desired. Microchannel system300includes a transversely-extending distribution passage302into which cooling air is channeled from a cooling air supply channel301, which has any suitable configuration sufficient to enable system300to function as described. In the exemplary embodiment, distribution passage302is positioned a distance F below a component surface304of a component305. Distribution passage302is coupled in flow communication to a plurality of feed passages306. Each feed passage306is coupled in flow communication with a corresponding delivery channel308. Air flows309are channeled in a direction indicated by the arrows. In the exemplary embodiment, each delivery channel308includes a section310that is configured with a substantially constant cross-sectional area along a length D, wherein the cross-sectional area is measured in a plane R extending perpendicularly to the direction of flow. In the exemplary embodiment, feed passages306and sections310are provided with dimensions similar to those of feed passages206and sections210illustrated inFIGS. 3 and 4.

Section310includes a side wall313and an opposite side wall315. Each section310terminates in a diffuser section312that is configured with diverging side walls314and316, and substantially parallel top wall318and bottom wall320, resulting in an increasing cross-sectional area along a length E, wherein the cross-sectional area is measured in a plane S extending perpendicularly to the direction of flow209. In the exemplary embodiment, length E is equal to about 3 to about 5 times a width X of channel section310. In other embodiments, length E is any length that enables system300to function as described. In the exemplary embodiment, one or both of walls314and316diverge from respective side walls313and315, in a manner similar that described with respect to walls214and216, illustrated inFIG. 3. Each diffuser section312is coupled in flow communication with discharge passage in the form of a transversely-extending trough322.

Trough322includes a first inlet end328, a bottom wall330, an inclined outlet end wall332that intersects surface304, an inclined first inlet end wall334, a more steeply inclined second inlet end wall336, a first side wall338, and a second side wall340opposite first side wall338. An edge342of second inlet end wall336, an edge344of first side wall338, an edge346of outlet end wall332, and an edge348of second side wall340define an opening350of trough322. In the exemplary embodiment, outlet end wall332and edge344or edge348(both of which are located at surface304) define between them an angle β, wherein β is between about 20° and about 90°. In other embodiments, any other value for β is used that enables system300to function as described herein. Moreover, one or both of walls334and336defines a similar angle (not shown) with respect to edges344and/or348(and correspondingly to surface304). As described with respect to system200, angle β does not have to be constant along the length of walls334and/or336. In the exemplary embodiment, distribution passage302and feed passages306have any cross-sectional configuration, including but not limited to circular, oval, square, rectangular, or polygonal, that enables system300to function as described herein. In the embodiment ofFIG. 5, delivery channels308(including sections310and diffuser sections312) have rectangular cross-sectional configurations. In alternative embodiments, delivery channels308have any other cross-sectional configuration that enables system300to function as described herein. In an alternative embodiment (not shown), trough322may be extended in the direction of channel sections310, to accommodate a pin-bank (not shown) that includes a plurality of spaced-apart pins that extend between bottom wall330and end wall334.

In the exemplary embodiment, air supply channel301, distribution passage302, feed passages306, delivery channels308, and/or trough322are defined using any suitable passage-defining method, such as that described above with respect to system200. After air supply channel301, distribution passage302, feed passages306, and delivery channels308are defined, using any of the methods described herein, one or more cover layers (not shown), as described with respect to system200ofFIGS. 3 and 4, are coupled to component305to form at least part of outer surface304. After coupling of the one or more cover layers, trough322is defined, using any method as described herein. In an alternative embodiment, one or more of structures306,308, and/or322is cast-in, as described herein.

In operation, as illustrated inFIG. 5, cooling air flow307is channeled from air supply channel301into distribution passage302, where flow307is divided into a plurality of flows309that are channeled through feed passages306and into delivery channels308. As flows309are discharged from sections310and enter diffuser sections312, flows309are facilitated to expand (“diffuse”) as they are channeled into trough322. In trough322, flows309merge, and are discharged from trough322as a film311. As outlet end wall332diverges from first inlet end wall334, and particularly also from second inlet end wall336, cooling air within trough322is further diffused prior to discharge from trough322as film311.

FIG. 6is a top perspective view of another alternative exemplary microchannel system400that can be used in cooling system137.FIG. 7is a side perspective view of microchannel system400. Microchannel system400is used to supply cooling air through any structure within engine100(shown inFIGS. 1 and 2) for which both internal cooling and surface film cooling are desired. Microchannel system400includes a transversely-extending distribution passage402into which a cooling air flow407is channeled from a cooling air supply channel401, which has any suitable configuration sufficient to enable system400to function as described. In the exemplary embodiment, distribution passage402is positioned a distance I below a component surface404(shown inFIG. 7) of a component405. Distribution passage402is coupled in flow communication to a plurality of feed passages406. Each feed passage406is coupled in flow communication with a corresponding delivery channel408. Air flows409are channeled in a direction indicated by the arrows.

In the exemplary embodiment, each delivery channel408includes a section410that is configured with a substantially constant cross-sectional area along a length G, wherein the cross-sectional area is measured in a plane T extending perpendicularly to the direction of flow. In the exemplary embodiment, feed passages406and sections410are provided with dimensions similar to those of feed passages206and sections210illustrated inFIGS. 3 and 4. Each section410includes a side wall413and an opposite side wall415. Each section410terminates in a diffuser section412that is configured with diverging side walls414and416(shown inFIG. 7), and substantially parallel top wall418and bottom wall420. In the exemplary embodiment, wall314diverges from side wall413and/or wall416diverges from side wall415, in a manner similar that described with respect to walls214and216, illustrated inFIG. 3. Section412includes an increasing cross-sectional area along a length H (illustrated inFIG. 7), wherein the cross-sectional area is measured in a plane U extending perpendicularly to the direction of flow409. In the exemplary embodiment, diffuser section412has a length that is equal to about 3 to about 5 times a width Y of channel section410. In other embodiments, diffuser section412has any length that enables system400to function as described. Each diffuser section412is coupled in flow communication with a discharge passage in the form of an inclined nozzle422.

Each nozzle422includes a first inlet end428, an inclined outlet end wall430that intersects component surface404, an inclined inlet end wall432, a first side wall434, and a second side wall436opposite first side wall434. An edge438of inlet end wall432, an edge440of first side wall434, an edge442of outlet end wall430, and an edge444of second side wall436define an opening446of each nozzle422. In the exemplary embodiment, walls430and432diverge, while walls434and436are substantially parallel. In the exemplary embodiment, outlet end wall430and edge440or edge444, both of which are located at surface404(shown inFIG. 7) define between them an angle γ, wherein γ is between about 20° and about 90°. In other embodiments, any other value for γ is used that enables system300to function as described herein. Moreover, wall432defines an angle δ with respect to edge440and/or444, wherein δ is between about 20° and about 90°. In an alternative embodiment, walls430and432are substantially parallel, while walls434and436diverge, in a manner similar to walls214and216(shown inFIG. 3). In another alternative embodiment, all of walls430,432,434, and436diverge.

In the exemplary embodiment, distribution passage402and feed passages406have any cross-sectional configuration, including but not limited to circular, oval, square, rectangular, or polygonal, that enables system400to function as described herein. In the embodiment ofFIGS. 6 and 7, delivery channels408(including sections410and diffuser sections412) have rectangular cross-sectional configurations. In alternative embodiments, delivery channels408have any other cross-sectional configuration that enables system400to function as described herein.

FIG. 6also illustrates an alternative nozzle450that can be used in microchannel system400. Alternative nozzle450(shown in broken lines), includes an inlet end452, an inclined bottom wall454that intersects surface404, an inclined top wall456, a first side wall458, and a second side wall460opposite first side wall458. An edge462of top wall456, an edge464of first side wall458, an edge466of bottom wall454, and an edge468of second side wall460define an opening470of alternative nozzle450.

In the exemplary embodiment, air supply channel401, distribution passage402, feed passages406, delivery channels408, and/or nozzles422and/or alternative nozzles450are defined using any suitable passage-defining method, such as that described above with respect to system200. Moreover, in the exemplary embodiment, air supply channel401, distribution passage402, feed passages406, delivery channels408, and/or nozzles422and/or alternative nozzles450have any suitable dimensions that enable microchannel system400to function as described herein. After air supply channel401, distribution passage402, feed passages406, and delivery channels408have been defined using any of the methods described herein, one or more cover layers (not shown), as described with respect to system200ofFIGS. 3 and 4, are coupled to component405to form at least part of component surface404. After coupling of the one or more cover layers, nozzles422are defined, using any method as described herein. In an alternative embodiment, one or more of structures406,408, and/or422is cast-in, as described herein.

In operation, as illustrated inFIG. 7, cooling air flow407is channeled from air supply channel401into distribution passage402, where flow407is divided into a plurality of flows409that are channeled through feed passages406and into delivery channels408. As flows409are discharged from sections410and enter diffuser sections412, flows409are facilitated to expand (“diffuse”) as they are channeled into nozzles422. Flows409and are discharged from nozzles422at surface404, and merge as a film411. As outlet end walls430diverge from inlet ends428, cooling air within nozzles422is further diffused prior to discharge from nozzles422.

FIG. 8is a top perspective view of an exemplary microchannel system500that can be used in cooling system137.FIG. 9is a side perspective view of microchannel system500. Microchannel system500is used to supply cooling air through any structure within engine100(shown inFIGS. 1 and 2) for which both internal cooling and surface film cooling are desired. Microchannel system500includes a transversely-extending distribution passage502into which cooling air is channeled from a cooling air supply channel501, which has any suitable configuration sufficient to enable system500to function as described. In the exemplary embodiment, distribution passage502is positioned a distance K below a component surface504(shown inFIG. 9) of a component505.

Distribution passage502is coupled in flow communication to a plurality of feed passages506. Each feed passage506is coupled in flow communication with a corresponding delivery channel508. In each delivery channel508, an air flow509proceeds in a direction indicated by the arrows. In the exemplary embodiment, each delivery channel508is configured with a substantially constant cross-sectional area along a length J, wherein the cross-sectional area is measured in a plane V extending perpendicularly to the direction of flow. Each delivery channel508is coupled in flow communication with a transversely-extending enclosed trench510. In the exemplary embodiment, feed passages506and delivery channels508are provided with dimensions similar to those of feed passages206and sections210illustrated inFIGS. 3 and 4.

Trench510is, in turn, coupled to a plurality of discharge passages in the form of inclined nozzles512. Each nozzle512includes an inlet end514, an inclined outlet end wall516that intersects surface504(shown inFIG. 9), an inclined inlet end wall518, a first side wall520, and a second side wall522opposite first side wall520. An edge524of inlet end wall518, an edge526of first side wall520, an edge528of outlet end wall516, and an edge530of second side wall522define an opening532of each nozzle512. In the exemplary embodiment, each of walls516,518,520, and522diverge from one another in the direction of flow509, as described with respect to walls214and216illustrated inFIG. 3and/or as described with respect to walls430and432illustrated inFIG. 7. In an alternative embodiment, side walls520and522are substantially parallel, while walls516and518diverge. In another alternative embodiment, walls518and516are substantially parallel, while walls520and522diverge.

In the exemplary embodiment, air supply channel501, distribution passage502, feed passages506, delivery channels508, trench510and/or nozzles512are defined using any suitable passage-defining method, such as that described above with respect to system200. Moreover, in the exemplary embodiment, air supply channel501, distribution passage502, feed passages506, delivery channels508, trench510and/or nozzles512have any suitable dimensions that enable microchannel system500to function as described herein. After air supply channel501, distribution passage502, feed passages506, delivery channels508, and trench510have been defined using any of the methods described herein, one or more cover layers (not shown), as described with respect to system200ofFIGS. 3 and 4, are coupled to component505to form at least part of component surface504. After coupling of the one or more cover layers, nozzles512are defined, using any method as described herein. In an alternative embodiment, one or more of structures506,508,510, and/or512is cast-in, as described herein.

In operation, as illustrated inFIG. 9, cooling air flow507is channeled from air supply channel501into distribution passage502, where flow507is divided into a plurality of flows509that are channeled through feed passages506and into delivery channels508. As flows509are discharged from delivery channels508and enter enclosed trench510, flows509merge and mix. Thereafter, the mixed flows are channeled into nozzles512and discharged at surface504as separate flows that merge again to define film511.

The invention described herein provides several advantages over known systems and methods of cooling turbine structures using microchannels. Specifically, the microchannel systems described herein include diffuser sections, trenches, troughs, and/or discharge passages that provide the spreading and or diffusion of separate flows of cooling air, prior to discharge at a surface of a component that is cooled. In so doing, a higher film effectiveness is achieved for the exhausted coolant as it continues downstream. This reduces the temperature the downstream metal is exposed to thus enabling a greater amount of cooling to be achieved for a predefined cooling air flow rate. Exemplary embodiments of a method and a system for cooling turbine components are described above in detail. The method and system are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the systems and methods described herein are not limited to practice only with gas turbine rotor and stator blades, but also may be used in combination with other turbine components, including but not limited to combustor liners, transition pieces, and fuel nozzles. Moreover, the exemplary embodiment can be implemented and utilized in connection with many other rotary machine applications, other than gas turbines.