Gas engine component with cooling passages in wall

A ceramic structure may include a sacrificial ceramic core. The sacrificial ceramic core may include a ceramic body corresponding to a cooling cavity of a heat exchanger segment. The ceramic body may have an exterior surface that includes an outer surface and an inner surface interconnected to one another by at least a leading edge, a trailing edge, a tip facing edge and a base facing edge. The ceramic body may define a plurality of apertures extending between the outer surface and the inner surface. The ceramic body may include a trailing first pin and a leading first pin. The trailing first pin and the leading first pin may extend away from the inner surface. The leading first pin may be spaced away from the trailing first pin and in closer proximity to the leading edge than the trailing first pin.

TECHNICAL FIELD

This disclosure relates to components for gas turbine engines and methods of making the same, and in particular to casting gas turbine engine components.

BACKGROUND

Gas turbine engine components, such as turbine blades or vanes, experience high thermal loads due to being exposed to hot gases during engine operation. Overexposure to heat or higher temperatures can have significant impact to the lifecycle of the component. As a result, heat management strategies have been used to provide cooling to such components. One such strategy is to configure the component to allow for transpirational cooling which requires the addition of internal cooling channels and passages formed in the component. Investment casting is a well-known technique for the production of such components with cooling cores. Although investment casting techniques utilize individual ceramic cores for producing many types of cast gas turbine engine components, the need remains for an improved ceramic casting core and methods of use.

BRIEF SUMMARY

A method of manufacturing a gas turbine engine component is disclosed. One step includes providing a ceramic structure including a sacrificial ceramic core. The sacrificial ceramic core has a ceramic body corresponding to a cooling cavity of a heat exchanger segment that will be formed in the wall structure of the final cast component. The ceramic body has an exterior surface defined by an outer surface and an inner surface interconnected to one another by a leading edge, a trailing edge, a tip facing edge and a base facing edge. The ceramic body defines a plurality of apertures extending between the outer surface and the inner surface. The plurality of apertures corresponds to a plurality of pedestals within the cooling cavity of the heat exchanger segment. The ceramic body includes a trailing first pin and a leading first pin corresponding to a first inlet orifice and a second inlet orifice leading to the cooling cavity of the heat exchanger segment. The trailing first pin and the leading first pin are extended away from the inner surface. The leading first pin is spaced from the trailing first pin and in closer proximity to the leading edge than the trailing first pin. Another step includes inserting the ceramic structure into a casting mold. Another step includes introducing a component material into the casting mold. Another step includes removing the ceramic structure after the component material has solidified to define a casted component having the cooling cavity of the heat exchanger segment. A gas turbine engine component and a sacrificial ceramic core used to form a heat exchanger segment within a casted component are also disclosed.

DETAILED DESCRIPTION

Disclosed herein are examples of components for gas turbine engines and methods of manufacturing the same that may be used in any industry, such as, for example, to power aircraft, watercraft, power generators, and the like. The components have improved cooling configurations such that the components withstand high temperature environments that may exceed 2,500 degrees Fahrenheit. For example, the components include a wall structure having various configurations of cooling cavities of thin heat exchanger segments described herein to permit heat transfer coefficients to be manipulated across different regions of the component. The cavity configuration including the inflow and outflow orifices may be shaped, sized and include any number of pedestals, partitions, or diffusers to produce such varying heat transfer coefficient across the component's region. Such cavity configurations may be fabricated as three-dimensional ceramic cores, which are used in investment castings for producing the component into final form. However, such three-dimensional ceramic cores may be fragile and susceptible to cracking or breaking during the process of fabricating the cores, creating and curing the wax patterns or pouring the molten metal alloy into a casting mold. Spacing the arrangement of pins coupling between the ceramic core and the ceramic core mass may increase the stability of the core and reduce core deflection during the processing. As a result, along with other benefits, the quality of the wall and its thickness that surrounds the cooling cavity and the heat transfer capability of the thin heat exchanger from counterflow cooling within the cavity may be improved.

With reference toFIG. 1a gas turbine engine generally indicated at10includes, in axial flow series, an air intake12, a propulsive fan14, an intermediate pressure compressor16, a high pressure compressor18, combustion equipment20, turbine section21(a high pressure turbine22, an intermediate pressure turbine24, a low pressure turbine26, or a combination thereof) and an exhaust nozzle28disposed about a longitudinal axis (X-X) of the gas turbine engine10. The gas turbine engine10works in the conventional manner so that air entering the air intake12is accelerated by the propulsive fan14to produce two air flows, a first air flow into the intermediate pressure compressor16and a second airflow which provides propulsive thrust. The intermediate pressure compressor16compresses the air flow directed into it before delivering the air to the high pressure compressor18where further compression takes place.

The compressed air exhausted from the high pressure compressor18is directed into the combustion equipment20via a diffuser inlet where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through and thereby enter via a turbine nozzle of the turbine section21and drive the high, intermediate and low pressure turbines22,24and26before being exhausted through the exhaust nozzle28to provide additional propulsive thrust. The high, intermediate and low pressure turbines22,24and26respectively drive the high and intermediate pressure compressors16and18and the fan14by suitable interconnecting shafts.

Fuel is directed into the combustor30through a number of fuel injectors (not shown) located at the upstream end of the combustor30. The fuel injectors are circumferentially spaced around the engine10and serve to provide fuel into air derived from the high pressure compressor18. The resultant fuel and air mixture is then combusted within the combustor30.

Referring now toFIG. 2, a component110adapted for use in the gas turbine engine10, such as, but not limited to, any of the turbines of the turbine section21illustratively is shown as a turbine blade including an airfoil112. The airfoil112is generally elongated structure extending upwardly away from an airfoil base113coupled to a platform115of the component110along a blade axis118to an airfoil tip116. Although only one component110of a blade (and one airfoil112) is shown inFIG. 2, the airfoil112is one of a plurality of airfoils112included in the turbine section21. The plurality of airfoils112are supported by and circumferentially spaced about a disk that is rotatable about the longitudinal axis (X-X) of the gas turbine engine10. Fluid is directed toward the airfoils112from a plurality of static or stationary vanes (not shown) included in the turbine section21. Fluid flows from a leading edge122of the airfoil112to a trailing edge124of the airfoil112, thereby causing the plurality of turbine blades of the turbine section21to rotate to drive other rotating components of the gas turbine engine10.

Although the component110is shown as a turbine blade, the component110may include other hot gas path engine components, such as, for example, end walls, shrouds, or static turbine vanes (not shown) adapted for use in the gas turbine engine and including a wall structure similar to the wall structure140of the airfoil112. For example, when the component110is a turbine vane, the vane airfoil or more than one vane airfoil may be extended between a pair of outer and inner platforms, rather than one, which may be extended circumferentially about the longitudinal axis (X-X) of the gas turbine engine to form a ring. A plurality of vane airfoils may be circumferentially spaced about the longitudinal axis (X-X) such that the vane airfoils and the platforms cooperate to direct fluid flowing through the turbine section toward the airfoils112of the turbine blade and other downstream sections of the gas turbine engine.

Referring toFIG. 3, a cross-sectional view of the airfoil112taken along a line3-3inFIG. 2is shown. The airfoil112includes an outer shell126of a metal alloy, disposed along the blade axis118to define an internal core130extending along the blade axis118. The outer shell126extends along the blade axis118and fully wraps around the blade axis118. The outer shell126may be shaped to have a convex portion131forming a suction side132of the airfoil112and a concave portion133forming a pressure side134of the airfoil112opposite the suction side132. The core130is surrounded by the outer shell126and is substantially hollow in the illustrative embodiment to allow for the flow of cooling air from, for example, at least one of the compressors, through the core130of the airfoil112. The core130being substantially hollow means the core130may be entirely hollow or may be at least partially filled with an open-cell foam or other porous material and/or internal support ribs that still permit cooling air flow with the core130. The outer shell126may be an integrally formed unit or may be made of pieces that are joined or otherwise attached together.

As will be described, the airfoil112is adapted for a cooling system to help the component110withstand hot gas temperatures and potentially prolong the service life of the component110. The outer shell126is defined by a wall structure140configured as one or more heat exchanger segments or units127integrated within the wall structure140along any portion of the suction side132, the pressure side134, or both of the outer shell. The heat exchanger segment127formed in the wall structure140may include an internally formed cooling cavity, generally shown as142, surrounded by two or more walls, such as, for example, an outer wall160and an inner wall162. The wall structure140includes an exterior surface148and an interior surface150, opposite the exterior surface148. The exterior surface148and the interior surface150are separated from one another to define a wall structure thickness, as shown inFIG. 2. The exterior surface148is positioned radially outwardly of the core130relative to the interior surface150such that the exterior surface148faces away from the core130and the interior surface150faces toward the core130. Further, the inner wall162defines a plurality of inlet orifices154that is in fluid communication with the core130and the cavity142for passing cooling air from the core130to the cavity142. The outer wall160defines a plurality of outlet orifices156that is in fluid communication with the cavity142and exterior to the component110for passing cooling air from the cavity142to exit out of the airfoil112where the cooling air traverses along the exterior surface148of the airfoil112. To this end, the core130may be arranged in various configurations for receiving and passing cooling air. In an example, the core130may form a cooling chamber that extends through the base113and the airfoil112that is coupled to a cooling air source, as known in the art.

The outer wall160and the inner wall162may be generally follow the same contour of the respective exterior and interior surfaces148,150, and together define the cavity142. The outer wall160is defined by the exterior surface148of the wall structure140and a cavity facing surface164, opposite the exterior surface148. The inner wall162is defined by the interior surface150of the wall structure140and a cavity facing surface166, opposite the interior surface150. As illustrated inFIG. 3, the cavity142may be generally defined by the cavity facing surfaces164,166and further internal surfaces. For example, the cavity142may be further defined by a tip internal surface170, a base internal surface (not shown), a leading internal surface174and a trailing internal surface176. The tip internal surface170is oriented opposite the base internal surface and in closer proximity to the tip116than the base113of the airfoil112. The trailing internal surface176is oriented opposite to the leading internal surface174and in closer proximity to the trailing edge124than the leading edge122of the airfoil112.

A plurality of pedestals180may extend between the outer wall160and the inner wall162to support and maintain the relative positions of the walls. The pedestals180may also function as a thermal conductor for removing heat from the outer wall160for cooling within the cavity142or even transferring heat to the inner wall162for additional cooling from the core130. The pedestals180may have an elongated body formed with a variety of cross-sectional shapes, such as, but not limited to, circular, rectangular, triangular, elliptical, oval, star-shape or other shapes. In an example, the pedestals180may include the same shape having an equal cross-sectional area. In other example, the pedestals180may have different shapes and/or vary cross-sectional areas. The arrangement and number of the pedestals180may define intricacies of the shape of cavity142to allow sufficient cooling air flow through the cavity142to cool the outer wall160and the inner wall162. For example, the pedestals180may be distributed along different rows in a staggered, alternating pattern such that the cooling air may be diffused through the cavity142to remove heat.

As will be described, the airfoil112and the wall structure140may be formed using ceramic core investment casting techniques. Particularly, the cavity142defined in the wall structure140may be formed from the fabrication of a sacrificial ceramic core200appropriate for casting intricate structures within the wall structure140formed of a metal alloy described herein.

FIG. 4depicts a plan view of an example of the sacrificial ceramic core200that may be used to define the heat exchanger segment127and the cavity142of the airfoil112.FIG. 5depicts an end view of the sacrificial ceramic core200looking in the tip direction prior to adding the molten metal alloy. The sacrificial ceramic core200is spaced above a ceramic mass201that is in the shape of the internal core130of the final form of the airfoil112. This spacing would be sized for the desired thickness of the inner wall162. As will be described later, a plurality of first pins230may be coupled between the sacrificial ceramic core200and the ceramic mass201, and a plurality of second pins235are shown extending from the sacrificial ceramic core200in a direction away from the ceramic mass201. The approximate location of the mold cavity (shown generally by dashed lines208inFIG. 5) relative to the sacrificial ceramic core200and the ceramic mass201illustrates the formation of the outer shell126of the airfoil112.

In one example, a body210of the sacrificial ceramic core200includes an exterior surface211being defined by an outer surface212and an inner surface214(shown inFIG. 5) interconnected to one another by a leading edge216, a trailing edge218, a tip facing edge220and a base facing edge222. The body210as shown may be formed to have a curvature to match the contour of the respective exterior and interior surfaces148,150of the airfoil112. The outer surface212may correspond to the cavity facing surface164of the outer wall160, and the inner surface214may correspond to the cavity facing surface166of the inner wall162. The leading edge216may correspond to the leading internal surface174, the trailing edge218may correspond to the trailing internal surface176, the tip facing edge220may correspond to the tip internal surface170, and the base facing edge222may correspond to the base internal surface of the cavity142. In other words, the exterior surface211of the sacrificial ceramic core200corresponds to the general boundary of the cavity142. For example, wherever there is ceramic material forming the sacrificial ceramic core200, the ceramic material will eventually be removed, thereby defining an aspect of the configuration and spatial shape of the cavity142. The boundary of the cavity142, the shape, size and number of pedestals, partitions, and/or diffuser elements may be selected to produce the desired heat transfer coefficient across a region of the component110. The outer wall160and the inner wall162of the wall structure140follow the contour of the convex portion131(or concave portion133) of the outer shell126.

A plurality of apertures225may be formed in the sacrificial ceramic core200and extend through the outer surface212and the inner surface214. The apertures225may correspond to the pedestals180, by permitting the molten metal alloy to flow through the apertures225during the casting process and eventually solidify to form the pedestals180. To this end, the shape, size and number of apertures225correspond to the shape, size and number of the pedestals180. In one example, the apertures225may be arranged in a series of linear rows disposed adjacent to one another. In another example, the apertures225in a first linear row may be offset or staggered with the apertures225in an adjacent, second row. The size of the apertures may such that an aperture225in a first linear row may encroach or overlap the aperture225in an adjacent, second linear row.

As will be described, pins may be used to define the inlet orifices154and the outlet orifices156. The pins may be the same material as the sacrificial ceramic core200. Alternatively or in addition, one or more of the pins may comprise a material different than the sacrificial ceramic core200. In one example, the pins have an elongated body formed with a variety of cross-sectional shapes, such as, but not limited to, circular, rectangular, triangular, elliptical, oval, star-shape or other shapes. Pins may be shaped the same having an equal cross-sectional area. Alternatively, one or more pins may have different shapes than other pins and/or having differing cross-sectional areas. For example, inFIG. 5, the inlet orifices154of the airfoil112may be formed by any number of first pins230extending away from the inner surface214of the sacrificial ceramic core200by a length corresponding to the thickness of the inner wall162. The inlet orifices154may be disposed normal or obliquely angled about a first inlet axis232relative to the cavity facing surface166and the interior surface150. When compared to an inlet orifice disposed normal to such surface, inlet orifices154being obliquely angled may further reduce flow resistance as the cooling air moves from the internal core130of the airfoil112.

To this end, at least one of the first pins230may be oriented to define the eventual desired orientation of the inlet orifice154about the first inlet axis232. For example, at least one of the first pins (shown inFIG. 4as the first pins230A,230C) is shown extending at an oblique angle relative (that is, not normal to) to the inner surface214to place the core end231of the first pins230A,230C closer to the trailing edge218than the cavity end233of the first pins230A,230C. The core end231and the cavity end233of the first pins may be beveled. At least one of the first pins (shown inFIG. 4as the first pins230B,230D) corresponding to inlet orifices is shown extending at an oblique angle about a second inlet axis232′ relative (that is, not normal to) to the inner surface214to place the core end231of the first pins230B,230D closer to the leading edge218than the cavity end233of the first pins230B,230D. The first pins230being obliquely angled may form a wider base for the sacrificial ceramic core200to improve the stability of the sacrificial ceramic core200during the manufacturing and handling processes. The inlet orifices154may be disposed obliquely angled about the second inlet axis232′ relative to the cavity facing surface166and the interior surface150. Alternatively, one or more of inlet orifices formed by the first pins may be obliquely angled in the opposite direction than what is shown. Alternatively, the first pins230may be extended obliquely at a compound angle. That is, for example, the core end231of the first pin230A is closer to the trailing edge218and to the base edge222than the cavity end233of the first pin230A, and so forth for the other first pins and their respective edges.

The outlet orifice156of the airfoil112may be formed by any number of second pin235extending away from the outer surface212of the sacrificial ceramic core200by a length corresponding the thickness of the outer wall160.

The outlet orifices156may be disposed normal or obliquely angled about an outlet axis238relative to the cavity facing surface164and the exterior surface148. When compared to the outlet orifice disposed normal to such surfaces, the outlet orifices156that are obliquely angled may further reduce flow resistance as the cooling air moves out from the cavity142to the exterior of the airfoil112. To this end, at least one of the second pins235may be oriented to define the eventual desired orientation of the outlet orifice156about the outlet axis238. For example, at least one of the second pins (shown inFIG. 4as the second pins235A,235B,235D) is shown extending at an oblique angle relative (that is, not normal to) to the outer surface212to place the cavity end239of the second pins closer to the leading edge216than the exterior end240of the second pins. Alternatively, at least one of the second pins may extend at an oblique angle relative to the outer surface212to place the cavity end239of the second pins closer to the trailing edge218than the exterior end240of the second pins.

Alternatively, the outlet orifice156of the airfoil112may be formed after the casting process of the airfoil112by machining or drilling to form the orifice. Like the second pin orientation, the outlet axis238of the outlet orifice156when machined may extend perpendicular or obliquely to the outer surface212.FIG. 6shows an example of the sacrificial ceramic core200without the second pins235so that the outlet orifices156may be eventually machined after the casting process. Machining of the outlet orifices156may allow for better control of the angle of the outlet axis238and may allow for tighter control of the variation of hole diameter when compared to cast holes using the second pins235. When the sacrificial ceramic core200is secured to the ceramic mass201with any one of the first pin arrangements of the first pins230described herein, deflection of the sacrificial ceramic core during the casting processes may be further inhibited with omission of the second pins235, that is, by machining the outlet orifices156. In some examples, the interaction between the second pins235and the ceramic pattern shell that may be created as part of the investment casting process may create additional loads into the sacrificial ceramic core200during the processing.

The placement of the inlet orifices154relative to the outlet orifices156, and particularly the arrangement of the first pins230, may help improve the structural quality and heat transfer of the component110. Particularly, a first pin arrangement may include the placement of the first pin230A corresponding to a first inlet orifice spaced from another first pin (referred to now as230B) corresponding to a second inlet orifice by a lateral distance D1such that the first pin230B is closer to the leading edge122of the airfoil112than the first pin230A. The lateral distance D1is measured in a lateral direction between the leading edge122and the trailing edge124, perpendicular to the blade axis118, and may be suitable to inhibit a deflection and improve the stability of the sacrificial ceramic core200during the manufacture and handling processes. The placement of another first pin230D corresponding to a third inlet orifice may be spaced from the first pin230A corresponding to the first inlet orifice by a lateral distance, which is shown inFIG. 4as the same as the lateral distance D1, although the lateral distance may be less than or greater than the lateral distance D1.

In another first pin arrangement, at least another first pin230C and/or230D may be spaced by an axial distance from the respective first pin230A and/or230B, in addition to the lateral spacing of the first pins230A,230B, to further inhibit such deflection. For example, the placement of the first pin230D corresponding to the third inlet orifice may be spaced by an axial distance D2from the first pin230B corresponding to the second inlet orifice. The placement of the first pin230C corresponding to the fourth inlet orifice may be spaced from the first pin230A by an axial distance D3. The axial distance D3may be the same as the axial distance D2. In the example shown inFIG. 4, the axial distance D3is greater than the axial distance D2. The axial distances are measured along an axial direction of the blade axis118.

FIG. 4shows an example of a first pin arrangement with four first pins230A,230B,230C,230D. First pins230A,230C are shown disposed along the trailing edge218and the first pins230B,230D are shown disposed along the leading edge216. Particularly, the first pin230A may be disposed along the trailing edge218spaced from the base facing edge222by a distance X. The first pin230C may be disposed along the trailing edge218spaced from the tip facing edge220by a distance that may be equal to the distance X. The first pin230B may be disposed along the leading edge216spaced from the base facing edge222by a distance Y. In one example, the distance Y is greater than the distance X. The first pin230D may be disposed along the leading edge216spaced from the tip facing edge220by a distance that may be equal to the distance Y. The distance Y of the offset of both first pins230B,230D may locate the corresponding inlet orifices toward the center of the leading edge216. When the first pins230A,230B are placed at different locations and separated by the lateral distance D1, cooling air enters the cavity142through the inlet orifices located along both sides of the heat exchanger segment127such that cooling air streams A, B (shown superimposed on the sacrificial ceramic core200) are in a counterflow configuration and impinge against each other within the cavity142and may improve the performance of the heat exchanger segment127. Other arrangements of the first pins230may be possible, including any number of the first pins230at one end of the heat exchanger segment127and any number of the first pins230at the opposite end of the heat exchanger segment127. Furthermore, the first pins230may be distributed anywhere on the ceramic body exterior surface211—the tip facing edge220, base facing edge222, leading edge216, trailing edge218, and anywhere along the intermediate of the body210between the edges216,218,220,222. The size of the inlet orifices may also vary, which may depend on the cross-sectional area of the first pins230that vary along different locations of the ceramic body.

FIG. 4shows an example of a second pin arrangement, corresponding the outlet orifice arrangement, with four second pins235A,235B,235C,235D disposed along the leading edge216. Particularly, the second pin235A corresponding to a first outlet orifice may be disposed along the leading edge216proximate the base facing edge222. The second pin235D corresponding to a fourth outlet orifice may be disposed along the leading edge216proximate the tip facing edge220. Second pins235B,235C corresponding to second and third outlet orifices may be located in between the second pins235A,235D. In one example, the second pin235A corresponding to the first outlet orifice may be disposed closer to the base facing edge222than the second pin235A corresponding to the second outlet orifice and the first pins230B,230D corresponding to the second and third inlet orifices, respectively. Also, the first pin230D corresponding to the third inlet orifice may be disposed closer to the tip facing edge220than the second pins235A,235B corresponding to the first and second outlet orifices and the first pin230B.

In one example, the first pin230B corresponding to the second inlet orifice may be shown disposed between the second pins235A,235B corresponding to the first and second outlet orifices, and the first pin230D corresponding to the third inlet orifice may be shown disposed between the second pins235C,235D corresponding to the third and fourth outlet orifices. In one example, the second pins235B,235C corresponding to the second and third outlet orifices are shown disposed between the first pins230B,230D corresponding to the second and third inlet orifices.

In one example, the second pin235D corresponding to the fourth outlet orifice may be disposed closer to the tip facing edge220than the second pins235A,235B,235C corresponding to the first, third and second outlet orifices and the first pins230B,230D corresponding to the second and third inlet orifices. The second pin235B corresponding to the second outlet orifice may be disposed closer to the base facing edge222than the second pins235C,235D corresponding to the third and fourth outlet orifices and the first pin230D corresponding to the third inlet orifice, and the second pin235C corresponding to third outlet orifice may be disposed closer to the tip facing edge220than the second pins235A,235B corresponding to the first and second outlet orifices and the first pin230B corresponding to the second inlet orifice.

The heat exchanger segment127, that is, the sacrificial ceramic core200, may include other features to improve the performance of the heat exchanger segment. For example, as shown inFIG. 7, the heat exchanger segment127further includes a series of partitions that are defined by a series of channels300defined in the sacrificial ceramic core200. The channels300correspond to the partitions by permitting the molten metal alloy to flow through the sacrificial ceramic core200and eventually solidify to form the partitions within the heat exchanger segment127. The channels300are spaced from one another to define passageways between the partitions to facilitate direction of airstream flow such that the cooling air coming from the inlet orifices154does not immediately exit out of the outlet orifices156, thus short circuiting the heat exchanger segment. Adjacent channels are shown extending parallel to one another to define a flow passageway having a constant cross-sectional area. Alternatively, the adjacent channels may converge in a manner to define a flow passageway having a variable cross-sectional area to improve cooling air flow travel within the cavity. The channels300may be extended between the outer wall160and the inner wall162and extend in the lateral direction between the leading edge216and the trailing edge218. In one example, the channels300includes a first end302at the leading edge216and a second end304disposed at a location (for example, between about 50% and 80% of the lateral length) between the leading edge216and the trailing edge218. The channels300may be linear or wavy. The arrangement and number of the channels300may define intricacies of the shape of cavity142to allow sufficient cooling air flow through the cavity142to cool the outer wall160and the inner wall162.

Any number of channels may be included. In one example, the channel300A may be disposed between the second pin235A corresponding to the first outlet orifice and the first pin230B corresponding to the second inlet orifice. The channel300B may be disposed between the first pin230B corresponding to the second inlet orifice and the second pin235B corresponding to the second outlet orifice. The channel300C may be disposed between the second pin235C corresponding to the third outlet orifice and the first pin230D corresponding to the second inlet orifice. The channel300D may be disposed between the first pin230D corresponding to the second inlet orifice and the second pin235D corresponding to the fourth outlet orifice. In one example, the second pins235B,235C corresponding to the second and third orifices may not have the channel disposed between them allowing either orifices to receive the cooling air flow.

FIG. 8depicts another example of the sacrificial ceramic core200used to form the heat exchanger segment127including a diffuser element that may be formed by a curved or C-shaped opening400defined by the sacrificial ceramic core200and located at the end of the first pin230B that corresponds to the inlet orifice154. The C-shaped opening400permits the molten metal alloy to flow through the sacrificial ceramic core200and eventually solidify to form the curved wall of the diffuser element within the heat exchanger segment127to provide further support to the sacrificial ceramic core200. The C-shaped opening400may extend between the outer wall160and the inner wall162. The interior402defined by C-shaped opening400corresponds to a lumen of the diffuser element that is in fluid communication with the inlet orifice. The bridge404separating the C-shaped opening400from complete closure corresponds to a window of the diffuser element. The window may be located to face toward the trailing edge218. In its final form, cooling air enters into the lumen of the diffuser element and exits the lumen via the window. The bridge404corresponding to the window may be sized to allow the cooling air to travel farther away from the leading edge216than would be possible without the diffuser element. Each inlet orifice154may have a different configuration of the diffuser element. Depending on the cooling strategy, the C-shaped opening400may be fully enclosed to define a ring-shaped opening to eliminate cooling air flow from passing through the respective inlet orifice. The size and shape of the bridge404may vary among the associated inlet orifices to provide inlet orifices with different cooling characteristics.

FIG. 9depicts another example of an outlet orifice arrangement that may comprise of the second pins or machined orifices as described herein. For example, the outlet orifices may be disposed in an intermediate zone between the inlet orifices. Here, four second pins235A,235B,235C,235D or machined orifices may be disposed in an intermediate zone430disposed between the leading edge216and the trailing edge218. In one example, the four second pins235A,235B,235C,235D may be disposed at the center between the first pins230A,230C and the first pins230B,230D. For more even distribution of airflow, the second pins may be staggered. For example, the second pin235A may be disposed closer to the first pin230A than the first pin230B, the second pin235B may be disposed closer to the first pin230B than the first pin230A, the second pin235C may be disposed closer to the first pin230D than the first pin230C, and the second pin235D may be disposed closer to the first pin230C than the first pin230D.

FIG. 10depicts a perspective cutaway view of the airfoil112after the casting process. The wall structure140of the outer shell126includes the heat exchanger segment127(shown partially in dashed lines). The cooling cavity142is shown disposed between the outer wall160and the inner wall162. Inlet orifices154are in fluid communication between the cooling cavity142and the core130of the airfoil112. Outlet orifices156, shown in the outlet orifice arrangement shown inFIG. 9, are in fluid communication between the cooling cavity142and the exterior side148of the airfoil112.

FIG. 11depicts an example of the component110in the form of the airfoil112having a plurality of cooling regions500segmented along the airfoil112. Each cooling region500includes the heat exchanger segment527(shown in dashed lines) described herein. The cooling regions500may have the same or different heat transfer coefficients depending on the configuration of the heat exchanger segment127integrated into the wall structure140and cooling scheme strategy. The cooling regions500may be separated by a barrier502on one or more sides of the cooling region500formed, for example, by the material of the molten metal alloy. The cooling region500may be formed by the casting processes described herein, using the sacrificial ceramic cores200spaced from one another about the ceramic mass201by a gap that corresponds to the barrier502. The sacrificial ceramic cores200may have the same configuration or different configurations depending on the desired heat transfer coefficient for the cooling regions. As shown, the outlet orifices556are shown along different portions of the cooling regions.

FIG. 12depicts a flow diagram for a method600of manufacturing the component110, including one or more of the following steps or any combination thereof. The method600described herein using the sacrificial ceramic cores200have shown an improvement in the investment casting process.

At step602, a ceramic structure having one or more sacrificial ceramic cores200having any of the features described herein is provided. For example, the sacrificial ceramic core200may have a ceramic body corresponding to the cavity142of the heat exchanger segment127. The ceramic body has an exterior surface being defined by an outer surface and an inner surface interconnected to one another by a leading edge, a trailing edge, a tip facing edge and a base facing edge. The ceramic body defines a plurality of apertures extending between the outer surface and the inner surface. The plurality of apertures correspond to a plurality of pedestals within the cavity of the heat exchanger segment. A trailing first pin and a leading first pin correspond to a first inlet orifice and a second inlet orifice, respectively, leading to the cavity of the heat exchanger segment. The trailing first pin and the leading first pin extend from the inner surface. The leading first pin may be spaced from the trailing first pin and in closer proximity to the leading edge than the trailing first pin.

In one example, additive manufacturing may be used to fabricate each sacrificial ceramic core200. For example, successive sheet layers of mold material are built and stacked to create a three dimensional mold for the sacrificial ceramic core200. Each single sheet layer of mold material may be fabricated to define areas of material and voids where appropriate. When single sheet layers of mold material are stacked successively and joined or attached together, for example, by an adhesive or cured, the three dimensional mold may be created having the desired three dimensional passageway from the adjoining areas of voids. The three dimensional mold may be appropriately sealed to form a core die capable of receiving and retaining ceramic slurry. Ceramic material may be introduced to three dimensional passageway and cured in order to define the desired shape of the sacrificial ceramic core200. For example, the three dimensional mold with the mold material may then be surrounded by a ceramic shell such as by using a dipping process. After ceramic cures, the mold material may be then removed to reveal the sacrificial ceramic core200. Mold material may function as a mold for casting a three dimensional ceramic structure, and which the mold material may then be removed from the sacrificial ceramic core200with a mold material removal process, such as, but not limited to, by dissolving, melting and/or vaporization without harming the sacrificial ceramic core200. Mold materials may be selected to achieve desired properties, such as thermal expansion (relative to the ceramic material) and/or its mode of being removed from sacrificial ceramic core200. Other processes may be included to build the three dimensional mold, such as the sheet layers themselves being casted in a respective mold (not shown) or being cut from an integrated sheet layers of mold material such as by laser cutting or water cutting.

The ceramic mass201and the first and/or second pins230,235may be formed integral with the sacrificial ceramic cores200, using the mold material to define the relative aspects of these features. Alternatively, the ceramic mass201and the first and/or second pins230,235may be formed separately from the sacrificial ceramic cores200using additive manufacturing or injection molding processes, which are then later attached or fixed in a secure manner to the one or more sacrificial ceramic cores200. Regardless, the sacrificial ceramic cores200, the ceramic mass201, the first and/or second pins230,235may form the ceramic structure that may withstand the temperature requirements necessary to survive the casting of the molten metal alloy.

At step604, the ceramic structure having the one or more sacrificial ceramic cores is inserted into a casting mold. Particularly, the ceramic structure defined at least in part by the one or more sacrificial ceramic core may be positioned within two joined halves of a metal casting mold. The casting mold defines an injection volume that corresponds to the desired shape of the airfoil112of the component110. Melted wax may be vacuum injected into a wax mold around the ceramic structure. After the wax hardens, the wax mold halves are separated and removed to reveal the ceramic structure encased inside a wax pattern that corresponds to the shape of the airfoil112. The wax pattern's outer surface may be then coated with a ceramic material, such as, for example, by a dipping process, to form the ceramic shell around the ceramic structure and wax pattern unit.

At step606, a component material in the form of a molten metal alloy is introduced into the casting mold. Particularly, upon curing of the ceramic shell and removal of the wax, a completed ceramic casting mold is available to receive molten alloy in the investment casting process. Molten metal alloy material is then cast into the ceramic casing mold.

At step608, the ceramic structure including the one or more sacrificial ceramic cores200is removed after the component material has solidified. Particularly, after the molten metal alloy has solidified, the ceramic structure, including the sacrificial ceramic cores200, the ceramic mass201, the first and/or second pins230,235, is removed by mechanical and/or chemical means to reveal the component110as a final cast alloy having the integrated heat exchanger segment127as shown inFIGS. 3 and 10. As described above, the outlet orifices may be formed leading from the cavity to the exterior of the component. In an example, one or more outlet orifices may be machined, with for example, by drilling or laser cutting, in the final cast alloy component such that the machined orifices are in fluid communication with the cooling cavity. In another example, one or more second pins may positioned to extend away from the outer surface of the ceramic body and form part of the ceramic structure prior to step604.

The subject-matter of the disclosure relates, among others, to the following aspects:

1. A method of manufacturing a gas turbine engine component, comprising:

providing a ceramic structure including a sacrificial ceramic core, the sacrificial ceramic core having a ceramic body corresponding to a cooling cavity of a heat exchanger segment, the ceramic body having an exterior surface comprising an outer surface and an inner surface interconnected to one another by a leading edge, a trailing edge, a tip facing edge and a base facing edge, the ceramic body defining a plurality of apertures extending between the outer surface and the inner surface, the plurality of apertures corresponding to a plurality of pedestals within the cooling cavity of the heat exchanger segment, the ceramic body including a trailing first pin and a leading first pin corresponding to a first inlet orifice and a second inlet orifice leading to the cooling cavity of the heat exchanger segment, the trailing first pin and the leading first pin extending away from the inner surface, the leading first pin spaced from the trailing first pin and in closer proximity to the leading edge than the trailing first pin;

inserting the ceramic structure into a casting mold;

introducing a component material into the casting mold; and

removing the ceramic structure after the component material has solidified to a casted component, the cast component including the heat exchanger element having the cooling cavity where the sacrificial ceramic core was disposed.

2. The method of aspect 1, wherein at least one of the trailing first pin and the leading first pin of the sacrificial ceramic core is obliquely angled relative to the inner surface.

3. The method of aspect 2, wherein the trailing first pin is obliquely angled relative to the inner surface, wherein a core end of the trailing first pin is closer to the trailing edge than a cavity end of the trailing first pin, wherein the cavity end of the trailing first pin is closer proximity to the inner surface than the core end of the trailing first pin.

4. The method of aspect 3, wherein the leading first pin is obliquely angled relative to the inner surface, wherein a core end of the leading first pin is closer to the leading edge than a cavity end of the leading first pin, wherein the cavity end of the leading first pin is closer proximity to the inner surface than the core end of the leading first pin.

5. The method as in any of aspects 2-4, wherein the leading first pin is obliquely angled relative to the inner surface, wherein a core end of the leading first pin is closer to the leading edge than a cavity end of the leading first pin, wherein the cavity end of the leading first pin is closer proximity to the inner surface than the core end of the leading first pin.

6. The method as in any of aspects 1-5, further comprising forming an outlet orifice in the casted component that is in fluid communication with the cooling cavity.

7. The method of aspect 6, wherein the forming an outlet orifice step comprises providing a second pin extending away from the outer surface of the ceramic body.

8. The method of aspect 6, wherein the forming an outlet orifice step comprises machining the outlet orifice into the casted component after the removing step.

9. The method as in any of aspects 6-8, wherein the outlet orifice is obliquely angled.

10. The method as in any of aspects 6-9, wherein the outlet orifice is disposed in an intermediate zone between the leading edge and the trailing edge.

11. The method as in any of aspects 6-10, wherein the ceramic body further defines a channel corresponding to a partition disposed within the cooling cavity of the heat exchanger segment, the channel extending between the outer surface and the inner surface and disposed between the formed outlet orifice and the leading first pin.

12. The method as in any of aspects 6-11, wherein the ceramic body further defines a C-shaped opening extending between the outer surface and the inner surface and disposed proximate the leading first pin, the C-shaped opening corresponding to a diffuser element within the cooling cavity of the heat exchanger segment.

13. The method as in any of aspects 1-12, wherein the ceramic body includes a second leading first pin corresponding to a third inlet orifice and a second trailing first pin corresponding to a fourth inlet orifice, the third inlet orifice and the fourth inlet orifice leading to the cooling cavity of the heat exchanger segment, and extending away from the inner surface, wherein the second leading first pin is spaced from the trailing first pin and in closer proximity to the leading edge than the trailing first pin, wherein a distance between the leading first pin and the second leading first pin is less than a distance between the trailing first pin and the second trailing first pin.

14. The method as in any of aspects 1-13, wherein the ceramic structure includes a ceramic mass, and the leading first pin and the trailing first pin coupled between the ceramic mass and the sacrificial ceramic core.

15. The method of aspect 14, wherein the ceramic structure includes another sacrificial ceramic core disposed about the ceramic mass.

16. A gas turbine engine component, comprising:

a wall structure defining a core, the wall structure having an exterior surface and an interior surface opposite the exterior surface, the interior surface facing the core; and

a heat exchanger segment integrated into a region of the wall structure, the heat exchanger segment comprising a single contiguous piece including a cooling cavity defined by at least an outer wall corresponding to the exterior surface, an inner wall corresponding to the interior surface, a leading internal surface, and a trailing internal surface opposite the leading internal surface, the leading internal surface and the trailing internal surface extending between the outer wall and the inner wall,

wherein the wall structure includes a plurality of pedestals disposed within the cooling cavity, interconnecting the outer wall to the inner wall,

wherein the inner wall of the heat exchanger segment defines a first inlet orifice and a second inlet orifice, the first inlet orifice and the second inlet orifice extending between the cooling cavity and the core, the second inlet orifice spaced from the first inlet orifice and in closer proximity to the leading internal surface than the first inlet orifice, wherein the outer wall of the heat exchanger segment defines an outlet orifice extending between the cooling cavity and the exterior surface.

17. The gas turbine engine component of aspect 16, wherein the inner wall of the heat exchanger segment defines a third inlet orifice extending between the cooling cavity and the core, the third inlet orifice spaced from the first inlet orifice and in closer proximity to the leading internal surface than the first inlet orifice, and wherein the inner wall of the heat exchanger segment defines a fourth inlet orifice extending between the cooling cavity and the core, the second and third inlet orifices spaced from the fourth inlet orifice and in closer proximity to the leading internal surface than the fourth inlet orifice, the first inlet orifice and the fourth inlet orifice disposed along the trailing internal surface, and the second inlet orifice and the third inlet orifice disposed along the leading internal surface.

18. The gas turbine engine component of aspect 17, wherein the outlet orifice is a first outlet orifice, the outer wall of the heat exchanger segment defining a second outlet orifice extending between the cooling cavity and the exterior surface, wherein the first outlet orifice and the second outlet orifice are disposed along the leading internal surface.

19. The gas turbine engine component of aspect 17, wherein the outlet orifice is a first outlet orifice, the outer wall of the heat exchanger segment defining a second outlet orifice extending between the cooling cavity and the exterior surface, wherein the first outlet orifice and the second outlet orifice are in an intermediate zone that is disposed between the leading internal surface and the trailing internal surface.

20. A sacrificial ceramic core used to form a heat exchanger segment within a casted component, comprising: a ceramic body including an exterior surface comprising an outer surface and an inner surface interconnected to one another by a leading edge, a trailing edge, a tip facing edge and a base facing edge, the ceramic body defining a plurality of apertures extending between the outer surface and the inner surface, and including a trailing first pin and a leading first pin each formed of a ceramic, the trailing first pin and the leading first pin extending away from the inner surface, the leading first pin spaced from the trailing first pin and in closer proximity to the leading edge than the trailing first pin,

wherein the trailing first pin is obliquely angled relative to the inner surface, wherein a core end of the trailing first pin is closer to the trailing edge than a cavity end of the trailing first pin, wherein the cavity end of the trailing first pin is closer proximity to the inner surface than the core end of the trailing first pin, and wherein the leading first pin is obliquely angled relative to the inner surface, wherein a core end of the leading first pin is closer to the leading edge than a cavity end of the leading first pin, wherein the cavity end of the leading first pin is closer proximity to the inner surface than the core end of the leading first pin.

While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible. Accordingly, the embodiments described herein are examples, not the only possible embodiments and implementations. Furthermore, the advantages described above are not necessarily the only advantages, and it is not necessarily expected that all of the described advantages will be achieved with every embodiment.