Patent Description:
The disclosure relates generally to turbine systems, and more particularly, to the delivery of cooling fluid to a component of a gas turbine system via an independent cooling circuit.

Gas turbine systems are one example of turbomachines widely utilized in fields such as power generation. A conventional gas turbine system generally includes a compressor section, a combustor section, and a turbine section. During operation of a gas turbine system, various components in the system, such as turbine blades, nozzle airfoils, and shroud segments are subjected to high temperature gas flows, which can cause the components to fail. Since higher temperature gas flows generally result in increased performance, efficiency, and power output of a gas turbine system, it is advantageous to cool the components that are subjected to high temperature gas flows to allow the gas turbine system to operate at increased temperatures and to extend the lifetime of the components of a gas turbine system.

Cooling (e.g., convection cooling, impingement cooling, etc.) is often provided by directing a flow of a cooling fluid through internal passages formed in the components of the gas turbine system. In many cases, the cooling fluid is provided by bleeding off a portion of the air discharged by the compressor section of the gas turbine system.

A thermal barrier coating (TBC) is often applied to the components of a gas turbine system to provide a protective heat shield, prevent damage due to high temperatures, and extend component life by reducing oxidation and thermal fatigue. Spallation of the TBC is a common issue in gas turbine systems. When the TBC spalls, portions of the TBC may crack and break off a component, exposing underlying surfaces to high temperatures and damage (e.g., a wall breach).

<CIT> describes a hot gas path (HGP) component of an industrial machine includes primary and secondary cooling pathways. A body includes an internal cooling circuit carrying a cooling medium. A primary cooling pathway is spaced internally in the body and carries a primary flow of a cooling medium from an internal cooling circuit. A secondary cooling pathway is in the body and in fluid communication with an internal cooling circuit. The secondary cooling pathway is fluidly incommunicative and spaced internally from the primary cooling pathway. In response to an overheating event occurring, the secondary cooling pathway opens to allow a secondary flow of cooling medium through to the outer surface of the body and/or the primary cooling pathway. The primary flow flows in the primary cooling pathway prior to the overheating event, and the secondary flow of cooling medium does not flow until after an opening of the secondary cooling pathway. <CIT> discloses an airfoil having a wall structure including a plurality of spaced walls for improved cooling and lifetime is disclosed. The airfoil and walls are made by additive manufacturing. The airfoil includes an exterior wall, an intermediate wall, and an interior wall each separated from adjacent walls by a plurality of standoff members; a plurality of outer cooling chambers defined between the exterior and intermediate walls, the chambers partitioned by an outer partition; a plurality of intermediate cooling chambers defined between the intermediate and interior walls, the chambers partitioned by an intermediate partition; a thermal barrier coating on each of the exterior wall and the intermediate wall; a first plurality of impingement openings through the intermediate wall; a second plurality of impingement openings through the interior wall; and a plurality of cooling passages through the exterior wall.

In light of the above, the problem of the present disclosure is to provide a component for a gas turbine system and a gas turbine system that has a less impaired baseline cooling effectiveness within the component in the event of surface damages occurring to the component.

This problem is solved with a component according to claim <NUM> and a gas turbine system according to claim <NUM>.

An aspect of the disclosure is in particular directed to a component of a gas turbine system, including: a plurality of independent circuits of cooling channels embedded within an exterior wall of the component, each independent circuit of cooling channels including a plurality of headers and a plurality of feed tubes fluidly coupling the plurality of headers to a supply of cooling fluid; and an impingement plate connected to the exterior wall of the component by the plurality of feed tubes of the independent circuits of cooling channels, wherein, in each of the plurality of independent circuits of cooling channels, the cooling fluid flows through the plurality of feed tubes and the plurality of headers into the circuit of cooling channels only in response to a formation of a breach in the exterior wall of the component that exposes at least one of the cooling channels of the circuit of cooling channels.

Another aspect of the disclosure is in particular directed to a gas turbine system, including: a component of a gas turbine system; and a cooling system for the component, the cooling system including: a plurality of independent circuits of cooling channels embedded within an exterior wall of the component, each independent circuit of cooling channels including a plurality of headers and a plurality of feed tubes fluidly coupling the plurality of headers to a supply of cooling fluid; and an impingement plate connected to the exterior wall of the component by the plurality of feed tubes of the plurality of independent circuits of cooling channels, wherein, in each of the plurality of independent circuits of cooling channels, the cooling fluid flows through the plurality of feed tubes and the plurality of headers into the circuit of cooling channels only in response to a formation of a breach in the exterior wall of the component that exposes at least one of the cooling channels of the circuit of cooling channels.

These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure.

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.

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

In addition, several descriptive terms may be used regularly herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, "downstream" and "upstream" are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through the turbine engine or, for example, the flow of air through the combustor or coolant through one of the turbine's component systems. The term "downstream" corresponds to the direction of flow of the fluid, and the term "upstream" refers to the direction opposite to the flow. The terms "forward" and "aft," without any further specificity, refer to directions, with "forward" referring to the front or compressor end of the engine, and "aft" referring to the rearward or turbine end of the engine. Additionally, the terms "leading" and "trailing" may be used and/or understood as being similar in description as the terms "forward" and "aft," respectively. It is often required to describe parts that are at differing radial, axial and/or circumferential positions. The "A" axis represents an axial orientation. As used herein, the terms "axial" and/or "axially" refer to the relative position/direction of objects along axis A, which is substantially parallel with the axis of rotation of the gas turbine system (in particular, the rotor section). As further used herein, the terms "radial" and/or "radially" refer to the relative position/direction of objects along a direction "R" (see, <FIG>), which is substantially perpendicular with axis A and intersects axis A at only one location. Finally, the term "circumferential" refers to movement or position around axis A (e.g., direction "C").

In various embodiments, components described as being "fluidly coupled" to or "in fluid communication" with one another can be joined along one or more interfaces. In some embodiments, these interfaces can include junctions between distinct components, and in other cases, these interfaces can include a solidly and/or integrally formed interconnection. That is, in some cases, components that are "coupled" to one another can be simultaneously formed to define a single continuous member. However, in other embodiments, these coupled components can be formed as separate members and be subsequently joined through known processes (e.g., fastening, ultrasonic welding, bonding).

When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to", "directly connected to" or "directly coupled to" another element, there may be no intervening elements or layers present.

<FIG> depicts a schematic diagram of a gas turbine system <NUM> according to various embodiments. As shown, the gas turbine system <NUM> includes a compressor section <NUM> for compressing an incoming flow of air <NUM> and for delivering a flow of compressed air <NUM> to a combustor section <NUM>. The combustor section <NUM> mixes the flow of compressed air <NUM> with a pressurized supply of fuel <NUM> and ignites the mixture to create a flow of combustion gases <NUM>. Although only a single combustor section <NUM> is shown, the gas turbine system <NUM> may include any number of combustor sections <NUM>. The flow of combustion gases <NUM> is in turn delivered to a turbine section <NUM>. The flow of combustion gases <NUM> drives the turbine section <NUM> to produce mechanical work. The mechanical work produced in the turbine section <NUM> drives the compressor section <NUM> via a shaft <NUM> and may be used to drive an external load <NUM>, such as an electrical generator and/or the like.

<FIG> depicts a side view of a portion of a turbine section <NUM> of a gas turbine system, including at least one stage <NUM> of turbine blades <NUM> (one shown) and at least one stage <NUM> of nozzles <NUM> (one shown) positioned within a casing <NUM> of the turbine section <NUM>. Each stage <NUM> of turbine blades <NUM> includes a plurality of turbine blades <NUM> that are coupled to and positioned circumferentially about the rotor <NUM>, and which are driven by the combustion gases <NUM>. Each stage <NUM> of nozzles <NUM> includes a plurality of nozzles <NUM> that are coupled to and positioned circumferentially about the casing <NUM> of the turbine section <NUM>. In the embodiment shown in <FIG>, each nozzle <NUM> includes an airfoil <NUM> positioned between an outer platform <NUM> and an inner platform <NUM>.

Similar to the nozzles <NUM>, each turbine blade <NUM> of the turbine section <NUM> includes an airfoil <NUM> extending radially from the rotor <NUM>. Each airfoil <NUM> includes a tip portion <NUM> and a platform <NUM> positioned opposite the tip portion <NUM>.

The turbine blades <NUM> and the nozzles <NUM> may be positioned axially adjacent to one another within the casing <NUM>. In <FIG>, for example, the nozzles <NUM> are shown positioned axially adjacent and downstream of the turbine blades <NUM>. The turbine section <NUM> may include a plurality of stages <NUM> of turbine blades <NUM> and a plurality of stages <NUM> of nozzles <NUM>, positioned axially throughout the casing <NUM>.

The turbine section <NUM> of the gas turbine system <NUM> may include a plurality of stages <NUM> of shrouds <NUM> (one stage shown in <FIG>) positioned axially throughout the casing <NUM>. In <FIG>, for example, the stage <NUM> of shrouds <NUM> is shown positioned radially adjacent to and substantially surrounding or encircling the stage <NUM> of turbine blades <NUM>. The stage <NUM> of shrouds <NUM> may also be positioned axially adjacent and/or upstream of the stage <NUM> of nozzles <NUM>. Further, the stage <NUM> of shrouds <NUM> may be positioned between two adjacent stages <NUM> of nozzles <NUM> located on opposing sides of a stage <NUM> of turbine blades <NUM>. The stage <NUM> of shrouds <NUM> may be coupled about the casing <NUM> of the turbine section <NUM> using a set of extensions <NUM>, each including an opening <NUM> configured to receive a corresponding section of a shroud <NUM>.

Turning to <FIG>, a perspective view of a turbine blade <NUM> is shown. The turbine blade <NUM> includes a shank <NUM>, a platform <NUM> located radially above the platform <NUM>, and an airfoil <NUM> coupled to and extending radially outward from the platform <NUM>. The airfoil <NUM> includes a pressure side <NUM>, an opposed suction side <NUM>, and a tip portion <NUM>. The airfoil <NUM> further includes a leading edge <NUM> between the pressure side <NUM> and the suction side <NUM>, as well as a trailing edge <NUM> between the pressure side <NUM> and suction side <NUM> on a side opposing the leading edge <NUM>.

Many components of a gas turbine system (e.g., turbine blades, nozzles, shrouds, etc.) may be cooled during operation by directing a fixed supply of a cooling fluid through internal passages formed in the components. In many cases, the cooling fluid is provided by bleeding off a fixed supply of air discharged by the compressor section of the gas turbine system.

Many different internal cooling methodologies may be used to cool a component of a gas turbine system including, for example, convection cooling, film cooling, and impingement cooling. Convection cooling works by passing a flow of a cooling fluid through passages internal to the component. Heat is transferred by conduction through the component, and then to the cooling fluid flowing through the component. With film cooling, cooling fluid is discharged to an external surface of the component via small holes formed through an exterior wall of the component. The cooling fluid provides a thin, cool, insulating blanket along the external surface of the component. Impingement cooling, a variation of convection cooling, works by directing a higher velocity flow of a cooling fluid against an interior surface of the component. This allows more heat to be transferred by convection than regular convection cooling. Impingement cooling is often used in regions of the component exposed to high heat loads (e.g., the leading edge of a turbine blade).

If a breach forms (e.g., as a consequence of TBC spallation or other damage) in a portion of a component of a gas turbine system and exposes any internal cooling passages, some of the fixed supply of cooling fluid may flow from the exposed internal cooling passages and out of the component through the breach. This reduces the remaining amount of the fixed supply of cooling fluid available to the component, decreasing cooling effectiveness, and potentially resulting in component failure. An example of such a wall breach is depicted in <FIG>.

<FIG> depicts an example of impingement cooling in a component <NUM> of a gas turbine system (e.g., gas turbine system <NUM>, <FIG>). As shown, a supply of a cooling fluid <NUM> is directed against an inner surface <NUM> of an exterior wall <NUM> of the component <NUM> though a plurality of openings <NUM> formed in an impingement plate <NUM>. The outer surface <NUM> of the exterior wall <NUM> of the component <NUM> is exposed to a hot gas flow <NUM>. <FIG> depicts the component <NUM> with a breach <NUM> extending through the exterior wall <NUM>. As shown, a portion of the cooling fluid <NUM> escapes through the exterior wall <NUM> of the component <NUM> through the breach <NUM>, reducing available cooling to the component <NUM> causing damage to spread and potentially resulting in component failure.

According to embodiments, an independent cooling circuit is provided to deliver an additional, independent supply of cooling fluid to a component of a gas turbine system in response to a partial or full wall breach. The component may include, for example, a turbine blade, nozzle airfoil, shroud segment, combustion liner, or other component that may require cooling during operation of the gas turbine system. At least one interconnected circuit of cooling channels may be embedded within an exterior wall of the component. A plurality of coolant feed channels are provided within the component (e.g., within/on an impingement plate or insert, within/on an interior wall, and/or the like). A plurality of feed tubes fluidly couple the coolant feed channels and each interconnected circuit of cooling channels embedded within the exterior wall of the component. During normal operation (e.g., the absence of a partial or full breach in the exterior wall of the component), cooling fluid does not flow through the independent cooling circuit, since there is no outlet for the cooling fluid. However, when a partial or full wall breach occurs and exposes at least a portion of an interconnected circuit of cooling channels embedded within the exterior wall of the component, a flow path is created, which allows a supply of cooling fluid to flow toward the affected area through the independent cooling system. The cooling provided by this additional, independent flow of cooling fluid may extend the life of the component (e.g., reduce/prevent additional spallation in the area of the breach) after surface damage has occurred without affecting the baseline cooling effectiveness (e.g., impingement cooling) within the component.

A first embodiment of an independent cooling circuit <NUM> for a component <NUM> of a gas turbine system <NUM> (<FIG>) according to embodiments is illustrated in <FIG>. The component <NUM> may comprise any component of a gas turbine system <NUM> that may require cooling including, without limitation, a turbine blade, nozzle airfoil, shroud segment, combustion liner, etc. In this example, an impingement cooling arrangement <NUM> is used to cool an exterior wall <NUM> of the component <NUM>. For example, to provide impingement cooling, a supply of cooling fluid <NUM> may be directed into an internal cavity <NUM> of the component <NUM> during operation of the gas turbine system <NUM>. The supply of cooling fluid <NUM> may be provided, for example, by bleeding off a supply of air discharged by the compressor section <NUM> (<FIG>) of the gas turbine system <NUM>. The cooling fluid <NUM> flows from the internal cavity <NUM>, through a plurality of impingement holes <NUM> formed in an impingement plate <NUM>, into an impingement cavity <NUM>, and against an interior surface <NUM> of the exterior wall <NUM> of the component <NUM>. After impinging against the interior surface <NUM> of the exterior wall <NUM>, the cooling fluid <NUM> may be directed from the impingement cavity <NUM> to one or more interior/exterior areas of the component <NUM> (e.g., for film cooling). Although described in this and other embodiments in conjunction with impingement cooling, the independent cooling circuit <NUM> may be used together with other cooling arrangements (e.g., convection cooling, etc.).

The independent cooling circuit <NUM> depicted in <FIG> (referred to concurrently) includes a plurality of coolant feed channels <NUM> (although not always required depending on application), a plurality of feed tubes <NUM> connecting the impingement plate <NUM> to the exterior wall <NUM>, and an interconnected circuit <NUM> (<FIG>) of cooling channels <NUM> embedded within the exterior wall <NUM> of the component <NUM>. The interconnected circuit <NUM> of cooling channels <NUM> is fully enclosed within the exterior wall <NUM> of the component <NUM>, such that none of the cooling channels <NUM> extends to or is exposed at the outer surface <NUM> (e.g., the hot gas surface) of the exterior wall <NUM>. The coolant feed channels <NUM> may be attached to the impingement plate <NUM>, formed as part of or within the impingement plate <NUM>, or provided in any other suitable manner. According to embodiments, the nominal location of the feed tubes <NUM> may be midway between the intersections <NUM> to ensure coolant feed at a breach which is most likely to occur at the intersections <NUM>. In other embodiments, the feed tubes <NUM> may be located at or near the intersections <NUM>.

Each of the coolant feed channels <NUM> is fluidly coupled, via a plurality of openings <NUM> in the impingement plate <NUM> and a plurality of the feed tubes <NUM>, to the interconnected circuit <NUM> of cooling channels <NUM>. The coolant feed channels <NUM> are each fluidly coupled to a pressurized supply of cooling fluid <NUM> that is independent of the supply of cooling fluid <NUM> provided to the impingement cooling arrangement <NUM>. The supply of cooling fluid <NUM> may be provided by bleeding off a supply of air discharged by the compressor section <NUM> of the gas turbine system <NUM>, or in any other suitable manner (e.g., a source of compressed air provided by a source other than the compressor section <NUM> of the gas turbine system <NUM>). The interconnected circuit <NUM> of cooling channels <NUM> does not include an outlet for the cooling fluid <NUM>. The coolant feed channels <NUM>, if required, may also include individual passages feeding each feed tube <NUM>. In other embodiments, the coolant feed channels <NUM> may be integral to the exterior wall <NUM>.

In the embodiment shown in <FIG>, the cooling channels <NUM> of the interconnected circuit <NUM> may be embedded within the exterior wall <NUM> of the component <NUM> at approximately the same distance from the outer surface <NUM> of the exterior wall <NUM> (e.g., in a planar configuration). Further, the feed tubes <NUM> may extend approximately the same distance into the exterior wall <NUM> to the cooling channels <NUM> of the interconnected circuit <NUM>. Multiple intersections <NUM> may be provided to fluidly interconnect all of the cooling channels <NUM> of the interconnected circuit <NUM>. The cooling channels <NUM> may be arranged in a grid-like pattern (e.g., a rectangular grid) within the exterior wall <NUM> and may extend linearly between the feed tubes <NUM> and/or between the intersections <NUM>.

In other embodiments, the cooling channels <NUM> (or portions thereof) of the interconnected circuit <NUM> may be embedded within the exterior wall <NUM> at different distances from the outer surface <NUM> of the exterior wall <NUM>. This may require the feed tubes <NUM> to extend different distances into the exterior wall <NUM> to the cooling channels <NUM> of the interconnected circuit <NUM>. In addition, in other embodiments, instead of using a single pressurized supply of cooling fluid and a single interconnected circuit of cooling channels, multiple independent circuits of cooling channels may be used. A single pressurized supply of cooling fluid may be fluidly coupled to all of the circuits of cooling channels, or multiple, separate pressurized supplies of cooling fluid may be used, each fluidly coupled to one or more of the circuits of cooling channels. In embodiments where cooling feed channels <NUM> are not used, the pre-impingement cooling fluid <NUM> may be fed through the plurality of feed tubes <NUM> into the interconnected circuit <NUM> of cooling channels <NUM>.

Referring again to <FIG>, during normal operation (e.g., the absence of a partial or full breach in the exterior wall <NUM> of the component <NUM>), there is no flow of the cooling fluid <NUM> through the independent cooling circuit <NUM>, since the interconnected circuit <NUM> of cooling channels <NUM> is embedded and fully enclosed within the exterior wall <NUM> and does not include an outlet for the cooling fluid <NUM>. However, as shown in <FIG>, in response to a formation of a partial or full wall breach <NUM> in the exterior wall <NUM> of the component <NUM>, at least a portion of the cooling channels <NUM> in the exterior wall <NUM> of the component <NUM> may become exposed, providing an outlet for the cooling fluid <NUM>. To this extent, the cooling fluid <NUM> can now flow through the cooling channels <NUM> exposed by the wall breach <NUM>. In particular, the cooling fluid <NUM> may flow through the coolant feed channels <NUM>, the plurality of feed tubes <NUM>, and the cooling channels <NUM> of the interconnected circuit <NUM> toward and out of the cooling channels <NUM> exposed by the wall breach <NUM>. The cooling fluid <NUM> ultimately flows out of the exposed cooling channels <NUM> in the breach <NUM> to an exterior of the component <NUM>. In general, the flow rate of the cooling fluid <NUM> increases in the channels closest to the breach <NUM>. The flow of cooling fluid <NUM> provides additional cooling to the component <NUM> in the area adjacent the wall breach <NUM>, independently of any cooling provided by the impingement cooling arrangement <NUM>. The additional cooling provided by the cooling fluid <NUM> may, for example, reduce additional spalling or prevent additional spalling from occurring in the area of the breach <NUM>. This may prevent the breach <NUM> from increasing in size and may extend the operational life of the component <NUM>.

The independent cooling system <NUM> includes a single pressurized supply of cooling fluid <NUM>, a plurality of coolant feed channels <NUM>, a plurality of intersections <NUM> connecting the interconnected circuit <NUM> of cooling channels <NUM>, and a plurality of feed tubes <NUM>. Another embodiment of an independent cooling circuit <NUM> is depicted in <FIG>, referred to concurrently. The independent cooling circuit <NUM> includes a plurality (e.g., two in this example), of independent, unidirectionally interwoven circuits <NUM>, <NUM>.

The circuit <NUM> includes a plurality of headers <NUM>, a plurality of feed tubes <NUM> fluidly coupled to each header <NUM> and connecting the impingement plate <NUM> to the exterior wall <NUM>, and a plurality of cooling channels <NUM> extending between and fluidly coupled to the headers <NUM>. Similarly, the circuit <NUM> includes a plurality of headers <NUM>, a plurality of feed tubes <NUM> fluidly coupled to each header <NUM> and connecting the impingement plate <NUM> to the exterior wall <NUM>, and a plurality of cooling channels <NUM> extending between and fluidly coupled to the headers <NUM>.

The cooling channels <NUM>, <NUM> and their headers <NUM>, <NUM> are embedded within the exterior wall <NUM> of a component <NUM> of a gas turbine system <NUM> (<FIG>), and extend within the external wall <NUM> in the same direction as indicated by arrow A (<FIG>). Each of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> is fully enclosed within the exterior wall <NUM> of the component <NUM>, such that none of the cooling channels <NUM>, <NUM> extends to or is exposed at the outer surface <NUM> of the exterior wall <NUM> of the component <NUM>.

Unlike the cooling channels <NUM> of the interconnected circuit <NUM> described above with regard to <FIG>, which extend linearly between the feed tubes <NUM> and/or between the intersections <NUM>, the cooling channels <NUM>, <NUM> in the circuits <NUM>, <NUM> of the independent cooling circuit <NUM> may have a non-linear configuration (e.g., a zig-zag configuration as shown, a sinusoidal configuration, etc.). As depicted in <FIG>, for example, the cooling channels <NUM> in the circuit <NUM> may extend and weave in a zig-zag manner between the headers <NUM> within the external wall <NUM>, while passing around the headers <NUM> of the circuit <NUM>. Similarly, the cooling channels <NUM> in the circuit <NUM> may extend and weave in a zig-zag manner (in parallel to the cooling channels <NUM>) between the headers <NUM> within the external wall <NUM>, while passing around the headers <NUM> of the circuit <NUM>. To this extent, as shown most clearly in <FIG>, the cooling channels <NUM> of the circuit <NUM> and the cooling channels <NUM> of the circuit <NUM> form a fabric <NUM> of cooling channels <NUM>, <NUM> within the external wall <NUM> of the component <NUM>. Further, as shown most clearly in <FIG>, the distance between the cooling channels <NUM>, <NUM> and the outer surface <NUM> of the exterior wall <NUM> varies within and along the external wall <NUM>.

According to embodiments, a supply of cooling fluid <NUM>, <NUM> may be provided to the circuits <NUM>, <NUM>, respectively, of the independent cooling circuit <NUM> via the feed tubes <NUM>, <NUM>. The supplies of cooling fluid <NUM>, <NUM> may be independent of one another and may be provided by one or more different sources of cooling fluid (e.g., by bleeding off different portions of the of air discharged by the compressor section <NUM> of the gas turbine system <NUM>, by reusing the cooling fluid <NUM>, etc.). The cooling fluid <NUM>, <NUM> may be provided directly to the feed tubes <NUM>, <NUM> (e.g., from an internal cavity <NUM> of the component <NUM> (<FIG>), or may be provided via respective sets of coolant feed channels <NUM>, <NUM> (only one of each is shown in phantom in <FIG>). The coolant feed channels <NUM>, <NUM> (if used) may be attached to an impingement plate <NUM> in the component <NUM>, formed as part of or within the impingement plate <NUM>, or provided in any other suitable manner. Neither of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> includes an outlet for the supplies of cooling fluid <NUM>, <NUM>.

As in the embodiment illustrated in <FIG>, an impingement cooling system <NUM> may be provided to cool the exterior wall <NUM> of the component <NUM>. To provide impingement cooling, a supply of cooling fluid <NUM> is directed into an internal cavity <NUM> (see, e.g., <FIG>) of the component <NUM> during operation of the gas turbine system <NUM>. The cooling fluid <NUM> flows from the internal cavity <NUM>, through a plurality of impingement holes <NUM> (e.g., formed in the impingement plate <NUM>), into an impingement cavity <NUM>, and against an interior surface <NUM> of the exterior wall <NUM> of the component <NUM>.

During normal operation (e.g., the absence of a partial or full breach in the exterior wall <NUM> of the component <NUM>), there is no flow of cooling fluid <NUM>, <NUM> through either of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> of the independent cooling circuit <NUM>, since the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> are embedded and fully enclosed within the exterior wall <NUM> and do not include outlets for the cooling fluid <NUM>, <NUM>.

When a partial or full wall breach <NUM> (see, e.g., <FIG>) occurs in the exterior wall <NUM>, at least a portion of one or more of the cooling channels <NUM>, <NUM> in the exterior wall <NUM> of the component <NUM> may become exposed. Exposure of one or more of the cooling channels <NUM> in the circuit <NUM> creates an outlet for the cooling fluid <NUM>. As a result, the cooling fluid <NUM> can now flow through the feed tubes <NUM> and headers <NUM> into the cooling channels <NUM> toward (and out of) the cooling channel(s) <NUM> exposed by the wall breach <NUM>. Similarly, exposure of one or more of the cooling channels <NUM> in the circuit <NUM> creates an outlet for the cooling fluid <NUM>. The cooling fluid <NUM> can now flow through the feed tubes <NUM> and headers <NUM> into the cooling channels <NUM> toward (and out of) the cooling channel(s) <NUM> exposed by the wall breach <NUM>. The cooling fluid <NUM> will flow through the circuit <NUM> of cooling channels <NUM> only in response to an exposure of one or more of the cooling channels <NUM>. Likewise, the cooling fluid <NUM> will flow through the circuit <NUM> of cooling channels <NUM> only in response to an exposure of one or more of the cooling channels <NUM>. To this extent, one or both of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> may be activated depending on which cooling channel(s) <NUM>, <NUM> have been exposed by the wall breach <NUM>.

The flow of cooling fluid <NUM> and/or <NUM> via the independent cooling circuit <NUM> provides additional cooling to the component <NUM> in the area adjacent the wall breach <NUM>, independently of any cooling provided by the impingement cooling arrangement <NUM>. The additional cooling provided by the cooling fluid <NUM> and/or <NUM> may, for example, reduce additional spalling or prevent additional spalling from occurring in the area of the breach <NUM>. This may prevent the breach <NUM> from increasing in size and may extend the operational life of the component <NUM>.

The use of a plurality of independent circuits <NUM>, <NUM> and the non-linear configuration of the cooling channels <NUM>, <NUM> provides a longer flow path within the exterior wall <NUM> of the component <NUM>, which may enhance the heat transfer to the cooling fluid <NUM>, <NUM> and enhance the cooling effectiveness of the independent cooling circuit <NUM>. In addition, portions of the cooling channels <NUM>, <NUM> located closer to the outer surface <NUM> of the external wall <NUM> of the component <NUM> may become exposed in response to the formation of a shallower/smaller breach <NUM>. As a result, the independent cooling circuit <NUM> may activate sooner in response to a spallation event than the independent cooling circuit <NUM>, which has a planar configuration.

Comparing <FIG>, it can be seen that the independent cooling circuit <NUM> may provide a higher density of cooling channels <NUM>, <NUM> in the exterior wall <NUM> of the component <NUM> than the independent cooling circuits <NUM> (e.g., due to the woven configuration of the circuits <NUM>, <NUM>). The higher density may enhance the cooling effectiveness of the independent cooling circuit <NUM>.

In the independent cooling circuits <NUM>, <NUM>, the supplies of cooling fluid may be provided independently of the main supply of cooling fluid (e.g., the supply of cooling fluid <NUM> used for impingement cooling) to limit any reduction in back flow margin (BFM) if a large area of cooling channel(s) becomes exposed due to a spallation event. BFM is defined as the difference between the pressure of the cooling fluid inside a component <NUM> of the gas turbine system <NUM> and the local pressure of the combustion gases <NUM> (<FIG>) outside the component <NUM>. In the independent cooling circuit <NUM>, however, which includes multiple, independent circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM>, a combination of sources of cooling fluid may be used depending on the application. For example, one of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> may be fed by bleeding off compressed air from the compressor section <NUM>, while the other of the circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> may reuse cooling fluid from a main cooling circuit in the component <NUM> (e.g., cooling fluid <NUM> used for impingement cooling in the impingement cooling arrangement <NUM>), or some combination of such sources. In such a case, a spallation event may allow for extra cooling in the main cooling circuit while limiting reductions in the BFM.

A modification of the independent cooling circuit <NUM> depicted in <FIG> that utilizes a combination of sources of cooling fluid is illustrated in <FIG>. The independent cooling circuit <NUM> in <FIG> operates similarly to the previously described independent cooling circuit <NUM>. In particular, the circuit <NUM> of cooling channels <NUM> is fluidly coupled to the supply of cooling fluid <NUM> via feed tubes <NUM> and operates as described above. However, unlike in the independent cooling circuit <NUM>, the circuit <NUM> of cooling channels <NUM> in the independent cooling circuit <NUM> is fluidly coupled to the impingement cavity <NUM> (and thus the supply of cooling fluid <NUM>) via a plurality of openings <NUM> formed in the exterior wall <NUM> of the component <NUM>. When a wall breach <NUM> in the exterior wall <NUM> exposes at least a portion of one or more of the cooling channels <NUM>, the cooling fluid <NUM> can now flow from the impingement cavity <NUM> through the openings <NUM> into the circuit <NUM> of cooling channels <NUM> toward (and out of) the cooling channel(s) <NUM> exposed by the wall breach <NUM>. In this way, the cooling fluid <NUM> used for impingement cooling is reused by the independent cooling circuit <NUM>.

Various components and features of the independent cooling circuits <NUM>, <NUM>, <NUM> of the present disclosure may be formed using an additive manufacturing process. Advantageously, additive manufacturing enables the design and production of more customizable and intricate features.

As used herein, additive manufacturing may include any process of producing an object through the successive layering of material rather than the removal of material, which is the case with conventional processes. Additive manufacturing can create complex geometries without the use of any sort of tools, molds or fixtures, and with little or no waste material. Instead of machining components from solid billets of plastic or metal, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the part. Additive manufacturing processes may include but are not limited to: 3D printing, rapid prototyping (RP), direct digital manufacturing (DDM), binder jetting, selective laser melting (SLM) and direct metal laser melting (DMLM). In the current setting, DMLM or SLM have been found advantageous.

To illustrate an example of an additive manufacturing process, <FIG> shows a schematic/block view of an illustrative computerized additive manufacturing system <NUM> for generating an object <NUM>. In this example, the system <NUM> is arranged for DMLM, although it should be understood that the general teachings of the disclosure are equally applicable to other forms of additive manufacturing. The AM system <NUM> generally includes a computerized additive manufacturing (AM) control system <NUM> and an AM printer <NUM>. The AM system <NUM> executes code <NUM> that includes a set of computer-executable instructions defining the object <NUM> to physically generate the object <NUM> using the AM printer <NUM>. Each AM process may use different raw materials in the form of, for example, fine-grain powder, liquid (e.g., polymers), sheet, etc., a stock of which may be held in a chamber <NUM> of the AM printer <NUM>. According to embodiments, the object <NUM> may be made of a metal or metal compound capable of withstanding the environment of a gas turbine system <NUM> (<FIG>). As illustrated, an applicator <NUM> may create a thin layer of raw material <NUM> spread out as the blank canvas on a build plate <NUM> of AM printer <NUM> from which each successive slice of the final object will be created. In other cases, the applicator <NUM> may directly apply or print the next layer onto a previous layer as defined by code <NUM>. In the example shown, a laser or electron beam fuses particles for each slice, as defined by code <NUM>. Various parts of the AM printer <NUM> may move to accommodate the addition of each new layer, e.g., a build platform <NUM> may lower and/or chamber <NUM> and/or applicator <NUM> may rise after each layer.

The AM control system <NUM> is shown implemented on a computer <NUM> as computer program code. To this extent, the computer <NUM> is shown including a memory <NUM>, a processor <NUM>, an input/output (I/O) interface <NUM>, and a bus <NUM>. Further, the computer <NUM> is shown in communication with an external I/O device/resource <NUM> and a storage system <NUM>. In general, the processor <NUM> executes computer program code, such as the AM control system <NUM>, that is stored in memory <NUM> and/or storage system <NUM> under instructions from code <NUM> representative of the object <NUM>.

Additive manufacturing processes begin with a non-transitory computer readable storage medium (e.g., memory <NUM>, storage system <NUM>, etc.) storing code <NUM> representative of the object <NUM>. For example, the code <NUM> may include a precisely defined 3D model of the object <NUM> and can be generated from any of a large variety of well-known computer aided design (CAD) software systems. The AM control system <NUM> executes the code <NUM>, dividing the object <NUM> into a series of thin slices that it assembles using the AM printer <NUM> in successive layers of liquid, powder, sheet or other material.

Various components of a gas turbine system <NUM> (<FIG>), or portions of such components, may be produced using an additive manufacturing (AM) process (e.g., using AM system <NUM>, <FIG>). For example, at least a portion of an exterior wall of a component including an interconnected circuit of cooling channels may be produced via an AM process.

In <FIG>, for example, a wall coupon <NUM> for the component <NUM> depicted in <FIG> has been produced (e.g., printed) via an AM process. The wall coupon <NUM> includes a section <NUM> of the exterior wall <NUM> of the component <NUM>. At least a portion of the interconnected circuit <NUM> of cooling channels <NUM> is embedded within the wall section <NUM>. The wall coupon <NUM> further includes a plurality of feed tubes <NUM> fluidly coupled to the cooling channels <NUM>. To this extent, the wall coupon <NUM> forms a portion of the independent cooling circuit <NUM>, described above. According to other embodiments, the wall coupon <NUM> may be formed with at least a portion of the interconnected circuits <NUM>, <NUM> of cooling channels <NUM>, <NUM> embedded therein.

According to embodiments, the wall coupon <NUM> may be produced to any size via an AM process, and may be attached to another section <NUM> of the component <NUM> to form at least a portion of the independent cooling circuit <NUM> (see, e.g., <FIG>). The section <NUM> of the component <NUM> may be formed in a conventional manner (e.g., machined, cast, etc.) or may be formed using an AM process. It should be noted that the wall coupon <NUM> may configured for use in any of the independent cooling circuits <NUM>, <NUM>, <NUM> described herein. Attachment may be accomplished, for example, using brazing, welding, or other suitable metal-joining process. <FIG> depicts the wall coupon <NUM> attached (e.g., via brazing/welding) to an impingement plate <NUM> of the component <NUM> to form at least a portion of the independent cooling circuit <NUM>. In other embodiments, the entire cooling structure depicted in <FIG> may be formed using an AM process, and may be attached to a portion of a component <NUM> of a gas turbine system <NUM>.

An independent cooling circuit <NUM> formed using an AM printed wall coupon <NUM> may be strategically provided in those areas of a component <NUM> of a gas turbine system <NUM> that may be subject to spallation. This may be done, for example, without having to produce the entire component <NUM> using an AM process. Further, an independent cooling circuit <NUM> formed using an AM printed wall coupon <NUM> may be retrofittable into an existing component <NUM> of a gas turbine system <NUM> to repair areas previously damaged by spallation and/or to selectively provide enhanced cooling to areas of the component <NUM> subject to spallation as described above.

When producing the independent cooling circuits <NUM>, <NUM>, <NUM> (or portions thereof) using an AM process, excess powder removal may become a concern. Since the independent cooling circuits <NUM>, <NUM>, <NUM> do not have an outlet for the cooling fluid <NUM> (e.g., the circuits are purposefully dead ended), there is no easy way to used forced air to try to remove the excess powder.

According to embodiments, as depicted in <FIG> and described with reference to the wall coupon <NUM> produced using an AM process (<FIG>), a plurality of small openings <NUM> for powder removal may be provided (e.g., formed during the AM process) in the exterior wall section <NUM> of the wall coupon <NUM>. In <FIG>, for example, the openings <NUM> are shown extending from the interconnected circuit <NUM> of cooling channels <NUM> of the independent cooling circuit <NUM> through the exterior wall section <NUM> to the outer surface <NUM> of the wall coupon <NUM>.

The openings <NUM> provide an exit that can be used for the removal of excess powder. Powder may be removed, for example, using vibration or by forcing air into the interconnected circuit <NUM> of cooling channels <NUM> and out through the openings <NUM>. After powder removal, the openings <NUM> may be filled/sealed in any suitable manner (e.g., filled with metal, sealant, etc.) to close the independent cooling circuit <NUM>. The openings <NUM> may be filled/sealed prior to the subsequent application of a TBC coating on the outer surface <NUM> of the wall coupon <NUM>, or simply sealed by the TBC coating itself. In some cases, a spall event may unblock some of the sealed openings <NUM> before any of the interconnected circuit <NUM> of cooling channels <NUM> are exposed due to the formation of a breach. Cooling fluid <NUM> may then flow toward and out of the unblocked openings <NUM> via the independent cooling circuit <NUM>, providing an immediate cooling benefit.

Claim 1:
A component (<NUM>) of a gas turbine system (<NUM>) having a coolant delivery system for selectively delivering cooling fluid to the component (<NUM>), wherein the coolant delivery system comprises:
a plurality of independent circuits (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>) embedded within an exterior wall (<NUM>) of the component (<NUM>), each independent circuit (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>) including a plurality of headers (<NUM>, <NUM>) and a plurality of feed tubes (<NUM>, <NUM>) fluidly coupling the plurality of headers (<NUM>, <NUM>) to a supply of cooling fluid (<NUM>);
characterized by
an impingement plate (<NUM>) connected to the exterior wall (<NUM>) of the component (<NUM>) by the plurality of feed tubes (<NUM>, <NUM>) of the plurality of independent circuits (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>), and
an impingement cavity (<NUM>) separating the exterior wall (<NUM>) of the component (<NUM>) from the impingement plate (<NUM>), the plurality of feed tubes (<NUM>, <NUM>) of each independent circuit (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>) extending through the impingement cavity (<NUM>);
wherein, in each of the plurality of independent circuits (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>), the cooling fluid flows through the plurality of feed tubes (<NUM>, <NUM>) and the plurality of headers (<NUM>, <NUM>) into the circuit of cooling channels (<NUM>, <NUM>) only in response to a formation of a breach (<NUM>) in the exterior wall (<NUM>) of the component (<NUM>) that exposes at least one of the cooling channels (<NUM>, <NUM>) of the circuit (<NUM>, <NUM>) of cooling channels (<NUM>, <NUM>).