Reduced cross-flow connection cavity and casting method

Abstract

A cast component and casting method having a reduced cross-flow connection cavity may include a body. The body may define a plurality of internal flow channels. The plurality of internal flow channels may include a first internal flow channel and a second internal flow channel. The cast component may also include a plurality of connection cavities that hinder unintended fluid communication between the first internal flow channel and the second internal flow channel through the plurality of connection cavities.

Description

[0001] This application is a divisional application of the invention patent application with application number 201911066004.9 filed on November 4, 2019 and invention name “Reduced cross-flow connecting cavity and casting method”. Technical Field

[0002] The present subject matter relates generally to the production of components for gas turbine engines and, more particularly, to leachable casting cores and methods of manufacture. Background Art

[0003] A gas turbine engine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section in a series flow sequence. In operation, air enters the inlet of the compressor section, where one or more axial or centrifugal compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and combusted in the combustion section to provide combustion gases. The combustion gases are directed from the combustion section through a hot gas path defined in the turbine section and then discharged from the turbine section via the exhaust section.

[0004] In a particular configuration, the turbine section includes a high pressure (HP) turbine and a low pressure (LP) turbine in a series flow order. The HP turbine and the LP turbine each include various rotatable turbine components such as turbine rotor blades, rotor disks, and retainers, and various stationary turbine components such as stator vanes or nozzles, turbine shrouds, and engine frames. The rotatable turbine components and the stationary turbine components at least partially define a hot gas path through the turbine section. As the combustion gases flow through the hot gas path, heat energy is transferred from the combustion gases to the rotatable turbine components and the stationary turbine components.

[0005] Typical gas turbine engines include components with very fine cooling channels in the combustor and / or HP or LP turbine that allow higher gas temperatures. These cooling channels are generally formed during the casting process of the component. Casting is a common manufacturing technique for forming various components of gas turbine aircraft engines. Casting components involves a mold with a negative of the desired component shape. If a specific internal shape is desired, a core is placed in the mold. Once the mold is prepared and any cores are positioned, molten material is introduced into the mold. After the material cools, the mold is removed and the core can be leached from the cast component that reveals the internal shape.

[0006] In order to create cooling channels during casting, casting cores with multiple legs are produced. Without additional support, the legs are likely to deviate from their intended position during the casting process, which may cause the cooling channels to collapse into each other, resulting in "cross talk" or "kiss out". In order to improve producibility, a certain number of tie rods are required to fix the legs in the desired position. These tie rods are usually made of the same material as the core. With the tie rods fixing the legs, the core is fixed in the mold and the part is cast. Once casting is completed, the core is leached from the cast part, and the cast part reveals the desired cooling channels, but generally also reveals a plurality of connecting cavities formed by the multiple tie rods. These connecting cavities allow the cooling fluid to leave the designed cooling channels and are therefore undesirable.

[0007] Therefore, there is a need for an improved method for forming cooling passages in components. Summary of the invention

[0008] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0009] According to one embodiment of the present disclosure, an intermediate casting component includes a casting body, the casting body includes a first material; and a core, the core is in the casting body and includes a second material that is susceptible to leaching, the core further includes a plurality of legs, the plurality of legs are oriented to form a plurality of internal flow channels within the component; and a plurality of tie rods, the plurality of tie rods have a first tie rod end and a second tie rod end, the plurality of tie rods are connected to at least two of the plurality of legs, at least one of the plurality of tie rods is oriented to form a connecting cavity, the configuration of the connecting cavity is an obstacle to fluid communication between the plurality of internal flow channels, and wherein the connecting cavity serves as an obstacle to fluid communication through the connecting cavity, wherein at least one of the plurality of legs further includes at least two cavity obstacles, the at least two cavity obstacles have an upstream face and a downstream face opposite thereto, and wherein the first tie rod end faces the first downstream face, the second tie rod end faces the second downstream face or the second upstream face, at least one of the plurality of tie rods is formed as a coil, or the core includes a first core material that is susceptible to leaching treatment, wherein the core further includes a second core material that resists leaching treatment, and wherein at least one of the plurality of tie rods has a second core material portion.

[0010] According to another embodiment of the present disclosure, an intermediate casting component includes a casting body, the casting body includes a first material; and a core, the core is within the casting body and includes a second material that is easily leached, the core further including a plurality of legs, the plurality of legs are oriented to form a plurality of internal flow channels within the component; and a plurality of tie rods, the plurality of tie rods having a first tie rod end and a second tie rod end opposite thereto, the plurality of tie rods are connected to at least two of the plurality of legs, wherein at least one of the plurality of tie rods is oriented to form a connecting cavity between the plurality of internal flow channels within the casting component, and wherein the construction of the connecting cavity serves as an obstruction to fluid communication through the connecting cavity, wherein the connecting cavity has a first diameter and a second diameter, the first diameter is larger than the second diameter, and the second diameter establishes a restriction point within the connecting cavity, the restriction point is located along the connecting cavity at a point calculated to make the pressure at the first end of the connecting cavity equal to the pressure at the second end of the connecting cavity.

[0011] According to another embodiment of the present disclosure, an intermediate casting component includes a casting body, the casting body includes a first material; and a core, the core is in the casting body and includes a second material that is easily leached, the core further includes a plurality of legs, the plurality of legs are oriented to form a plurality of internal flow channels and a plurality of tie rods within the component, the plurality of tie rods have a first tie rod end and a second tie rod end opposite thereto, the plurality of tie rods are connected to at least two of the plurality of legs, wherein at least one of the plurality of tie rods is oriented to form a connecting cavity between the plurality of internal flow channels within the casting component, and wherein the construction of the connecting cavity serves as an obstacle to fluid communication through the connecting cavity, wherein at least one of the plurality of tie rods is connected to the first leg at an acute angle and to the second leg at an acute angle, and at least one tie rod includes a plurality of bends.

[0012] These and other features, aspects and advantages of the present invention will become more readily understood by reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the description with reference to the accompanying drawings, a complete and enabling disclosure of the present invention including its best mode is set forth for those skilled in the art. Among them:

[0014] Figure 1 shows a schematic cross-sectional view of an embodiment of a gas turbine engine according to the present invention;

[0015] Figure 2 shows a perspective projection of one embodiment of a plurality of casting tools for casting a component having a plurality of internal flow passages according to aspects of the present subject matter;

[0016] FIG. 3 a shows a perspective projection of one embodiment of an intermediate cast component of a gas turbine aircraft engine according to aspects of the present subject matter;

[0017] FIG. 3 b illustrates a perspective projection of one embodiment of a cast component according to aspects of the present subject matter;

[0018] FIG. 4 a depicts a cross-section of a casting of a cast component and a core having a plurality of turbulators according to aspects of the present subject matter;

[0019] FIG. 4 b depicts a cross-section of an embodiment of a cast component having a plurality of turbulators according to aspects of the present subject matter;

[0020] 5a depicts a cross-section of another embodiment of a casting of a cast component and a core having a plurality of turbulators according to aspects of the present subject matter;

[0021] FIG5 b depicts a cross-section of another embodiment of a cast component having a plurality of turbulators according to aspects of the present subject matter;

[0022] 6a depicts a cross-section of an embodiment of a cast component and leachable core having tie bars with multiple bends according to aspects of the present subject matter;

[0023] 6b depicts a cross-section of an embodiment of a cast component having a connecting cavity with multiple bends according to aspects of the present subject matter;

[0024] 7a depicts a cross-section of an embodiment of a cast component and leachable casting core having tie rods formed as coils according to aspects of the present subject matter;

[0025] 7b depicts a cross-section of an embodiment of a cast component having a connecting cavity formed as a coil, according to aspects of the present subject matter;

[0026] 8a depicts a cross-section of an embodiment of a cast component and leachable core having a tie rod configured to form a venturi according to aspects of the present subject matter;

[0027] 8b depicts a cross-section of an embodiment of a cast component having a connecting cavity configured as a venturi, according to aspects of the present subject matter;

[0028] 9a depicts a cross-section of an embodiment of a cast component and a leachable casting core having a portion of a non-leachable tie rod according to aspects of the present subject matter;

[0029] 9b depicts a cross-section of an embodiment of a cast component in which a portion of a tie rod remains after leaching, according to aspects of the present subject matter;

[0030] Fig.10 An exemplary computing device for use in accordance with aspects of the present subject matter is depicted;

[0031] Fig.11 A flow chart for casting a component having a plurality of internal flow passages is provided;

[0032] Fig.12 A flow chart for making a leachable casting core having multiple legs and fluid-impeding ties is provided; and

[0033] Fig.13 A flow chart for designing a leachable casting core with multiple legs and in the presence of fluid-impeding ties is provided.

[0034] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. DETAILED DESCRIPTION

[0035] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each embodiment is provided to explain the present invention, rather than to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0036] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another, and are not intended to indicate the position or importance of a single component.

[0037] The terms "upstream" and "downstream" refer to relative directions with respect to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0038] In general, the present subject matter is directed to cast components for gas turbine engines, and more specifically, to reduced cross flow connection cavities, leachable casting cores, and methods of manufacture. In one embodiment, tie rods are generally presented that can impede fluid communication through a created connection cavity. These tie rods employ various aerodynamic and structural concepts to impede or block fluid flow in the created connection cavity; including shape, low pressure areas, pressure balance, counter-rotation, and physical obstruction.

[0039] Now referring to the accompanying drawings, Figure 1A cross-sectional view of one embodiment of a gas turbine engine 100 that can be used within an aircraft according to aspects of the present subject matter is shown, wherein the engine 100 is shown with a longitudinal or axial centerline axis 112 extending therethrough for reference purposes. Although shown as a turbofan engine, any suitable engine may be used with what is described herein. For example, suitable engines include, but are not limited to, high bypass turbofan engines, low bypass turbofan engines, turbojets, turboprop engines, turboshaft engines, propeller engines, etc. The engine 100 will be discussed in detail below.

[0040] Figure 2 A perspective projection of one embodiment of a plurality of casting tools 200 for casting a component having a plurality of internal flow channels according to aspects of the present subject matter is shown. As shown, in several embodiments, the plurality of casting tools 200 includes a mold 202, the mold 202 including a first mold half 204 and a second mold half 206. The first mold half 202 and the second mold half 206 are formed with a negative part shape 208. When molten material is introduced into the mold 202, the negative part shape 208 establishes a part shape (FIG. 3a, 326) of the cast part (FIG. 3a, 300). The mold can be formed of any suitable material, such as metal, ceramic, or sand, including silica, olivine, chromate, zircon, and sodium silicate. It should be understood that although Figure 2 The embodiments are depicted in FIG. 1 as having at least two halves, but other single molds, such as those used in investment casting, and molds having more than two parts are also consistent with aspects of the present subject matter.

[0041] Still reference Figure 2 In the case where a specific internal shape is desired, a leachable casting core (hereinafter referred to as a "core") 210 is fixed in the mold 202 before the molten material is introduced. The core 210 defines the internal shape of the component of the resulting cast component, and in some embodiments, the core 210 is leached from the cast component (FIG. 3b, 300) after casting. It should be understood that the core 210 can be produced by any recognized manufacturing method including additive manufacturing methods, such as described in more detail below.

[0042] Leaching of the core 210 can be achieved by any suitable leaching treatment. The treatment can be selected based on the composition of the core 210, the composition of the casting assembly, and the core geometry. For example, a chemical leaching mechanism can be used to remove the ceramic core. This exemplary leaching process can include placing the casting in an autoclave and immersing the casting in an alkaline solution (e.g., aqueous or alcoholic sodium hydroxide or potassium hydroxide). The solution exposure can be at an elevated pressure (e.g., from 1MPa to 5MPa) and a moderately elevated temperature (e.g., 150°C to 400°C). The pressure and / or temperature can be cycled, and the solution can be stirred to maintain the alkaline solution exposed to the ceramic core and evacuate the reaction products.

[0043] Still reference Figure 2 In the depicted embodiment, the core 210 is shown as having a plurality of legs 212. The plurality of legs 212 have a serpentine shape so that when leached, a plurality of internal flow channels 302, 304 having a serpentine shape are generated within the cast component 300. In the depicted embodiment, the plurality of internal flow channels 302, 304 form a serpentine flow channel in the cast component 300. The plurality of legs 212 are held in place during casting by a plurality of tie rods 214. The tie rods 214 have a first tie rod end 218 and a second tie rod end 220. Like the other components of the core, after casting, the tie rods 214 are generally leached from the cast component 300, exposing a plurality of connecting cavities (FIG. 3b, 306). The tie rods 214 are configured such that when leached, the generated connecting cavities intentionally reduce or increase the pressure differential over a conventional 90° straight tie rod, depending on design considerations. For example, the tie rods 214 may include obstructions or may utilize static, dynamic, and total pressure as a design lever. The flow change for certain embodiments, compared to unimpeded flow through a 90° straight tie rod, ranges from a flow reduction of 0% to 50% (eg, 10% to 30%) of flow through a 90° straight tie rod.

[0044] FIG3a shows a perspective projection of one embodiment of an intermediate cast component of a gas turbine aircraft engine according to aspects of the present subject matter. As shown, the cast component 300 has an outer shape 326 formed by casting the component in the mold 202, and the cast component 300 has been removed from the mold 202. The cast component 300 includes a core 210 within the cast component 300. The cast component 300 includes a first material, and the core 210 includes a second material that is susceptible to leaching. The core 210 includes a plurality of legs 212 fixed in place by a plurality of tie rods 214.

[0045] Figure 3b shows a perspective projection of the embodiment of Figure 3a after leaching of the core 210. As shown, the cast component 300 has an external shape 326 formed by casting the component in the mold 202. The cast component 300 includes a plurality of internal flow channels 302, 304 and connecting cavities 306 therebetween. The plurality of internal flow channels 302, 304 and the connecting cavities 306 are defined by the core 210. Leaching of the core 210 enables fluid to flow within the plurality of internal flow channels 302, 304 and the connecting cavities 306. It should be understood that the plurality of internal flow channels 302, 304 can be configured in any desired configuration, including as serpentine cooling channels. It should be understood that in some embodiments, the cast component 300 can be a component of a gas turbine aircraft engine having internal fluid cooling channels. For example, the cast component 300 can be such as Figure 1 The buckets, blades, shrouds, struts or blade platforms shown.

[0046] FIG4a depicts a cross-section of a cast component 300 around a portion of a core 210 retained in a second mold half 206 after casting but before leaching, according to aspects of the present subject matter. As shown in FIG4a, the plurality of legs 212 include a plurality of turbulator formers 216. The plurality of turbulator formers 216 have an upstream face 228 and a downstream face 230 opposite the upstream face 228. The first tie rod end 218 contacts a first flow channel downstream of the turbulator face 230, and the second tie rod end 220 contacts a second flow channel downstream of the turbulator face 230.

[0047] FIG. 4 b depicts a cross-section of the cast component 300 of FIG. 4 a after the core 210 has been leached and removed from the second half 206 of the mold, according to aspects of the present subject matter. As shown in FIG. 4 b , the plurality of turbulator forming members 216 of the core 210 (now leached) establish a plurality of turbulators 308 within the plurality of internal flow passages 302 and 304. The plurality of turbulators 308 have an upstream face 310 and a downstream face 312 opposite the upstream face 310. The downstream face 312 defines a leading edge of a low pressure region 314 as the fluid flow advances in the direction indicated by the arrow (A). The plurality of connecting cavities 306 exposed by the leaching of the plurality of tie rods 214 are established to be in fluid communication with the low pressure region 314. The fluid communication of the connecting cavities 306 with the low pressure region 314 is used to hinder fluid communication through the connecting cavities.

[0048] FIG5a depicts a cross-section of another exemplary cast component 300 of a casting around a portion of a core 210 held in the second mold half 206 after casting but before leaching according to aspects of the present subject matter. As shown in FIG5a, the plurality of legs 212 include a plurality of turbulator forming members 216. The plurality of turbulator forming members 216 have an upstream face 228 and a downstream face 230 opposite the upstream face 310. The first tie rod end 218 is coupled in contact with the downstream face 230 on the first leg 232, and the second tie rod end 220 is coupled to the upstream face 228 on the second leg 234.

[0049] FIG. 5 b depicts a cross-section of the cast component 300 of FIG. 5 a after the core 210 is leached and removed from the second half 206 of the mold according to aspects of the present subject matter. As shown in FIG. 5 b, the first flow channel 302 maintains a first fluid flow having a first flow pressure. The second flow channel 304 maintains a second fluid flow having a second flow pressure. When the first and second flow pressures are used, the first fluid flow pressure is greater than the second fluid flow pressure. During casting, a plurality of turbulator forming members 216 establish a plurality of turbulators 308 within the first flow channel 302 and the second flow channel 304. The plurality of turbulators 308 have an upstream face 310 and a downstream face 312 opposite to the upstream face 310. When the fluid flow advances in the direction indicated by the arrow (A), the downstream face 312 defines the leading edge of the low pressure region 314. The first end 316 of the connecting cavity exposed by the leaching of the plurality of tie rods 214 is established to be in fluid communication with the low pressure region 314 of the first fluid flow channel 302. The connecting cavity second end 318 is in fluid communication with the upstream turbulator face 310 of the second fluid flow channel 304. By configuring the connecting cavity second end 318 to be in fluid communication with the upstream turbulator face 310, a portion of the second fluid flow is directed into the connecting cavity 306. Since the second fluid flow pressure is less than the first fluid flow pressure, directing a portion of the second fluid flow into the connecting cavity 306 while the connecting cavity first end is in fluid communication with the low pressure region 314 of the first fluid flow channel 302 results in an equalization of the pressure differential between the first fluid flow channel 302 and the second fluid flow channel 304. As the pressure differential is reduced or eliminated, the connecting cavity 306 becomes an impediment to fluid communication between the first fluid flow channel 302 and the second fluid flow channel 304.

[0050] FIG. 6a depicts a cross-section of a casting of a cast component 300 around a portion of a core 210 held in a second mold half 206 after casting but before leaching, according to aspects of the present subject matter. As shown in FIG. 6a, in some embodiments, a first tie rod end 218 is coupled to a first leg 232 at an acute angle relative to the first leg 232, and a second tie rod end 220 is coupled to a second leg 234 at an acute angle relative to the second leg 234. It should be understood that the intersection angles need not be the same and may be any angle other than perpendicular, such as 10° to 80° (e.g., 15° to 45°). The tie rod 214 is formed with a bend 222. In FIG. 6a, the plurality of bends 222 position the tie rod 214 in a "W" configuration, but it should be understood that any configuration with a bend 222 and any number of bends 222 are acceptable. For example, the tie rod 214 may have a "U" shape or an "S" shape. In some additional embodiments, the bends 222 can be asymmetric in magnitude and distribution along the tie rods 214. In still further embodiments, the intersection angle can be perpendicular and the tie rods 214 can be formed with bends 222 in accordance with aspects of the present subject matter.

[0051] FIG6 b depicts a cross-section of the cast component 300 of FIG6 a after the core 210 is leached and removed from the second mold half 206 according to aspects of the present subject matter. As shown in FIG6 b , the first internal flow channel 302 has a first channel outer surface 320, and the second internal flow channel 304 has a second channel outer surface 322. The connecting cavity first end 316 intersects the first channel outer surface 320 at an acute angle relative to the first channel outer surface 320. The connecting cavity second end 318 intersects the second channel outer surface 322 at an acute angle relative to the second channel outer surface 322. It should be understood that the intersection angles need not be the same and can be any angle other than perpendicular, such as 10° to 80° (e.g., 15° to 45°). Since the form of the connecting cavity 306 is determined by the form of the tie rod 214, the leaching of the tie rod 214 having the bend 222 results in the connecting cavity 306 having the bend 324. In FIG. 6 b, a plurality of bends 324 position the connection cavity 306 into a "W" configuration with three bends, but it should be understood that any configuration with bends 324 is acceptable. For example, as with the tie rod 214, the connection cavity 306 may have a "U" shape formed with one or three bends 324, or an "S" shape formed with two bends 324. In some other embodiments, the plurality of bends 324 may be asymmetric in both amplitude and distribution along the connection cavity 306. The bends 324 determine the change in fluid direction, which increases the resistance to be overcome by the fluid. Thus, the bends 324 in the connection cavity 306 produce a configuration that hinders fluid communication through the connection cavity 306. It should be understood that certain bend arrangements may also be used to offset the Coriolis and centrifugal forces acting on the cooling fluid in certain casting components 300 of the gas turbine aircraft engine. It should also be understood that in still further embodiments according to aspects of the present subject matter, the intersection angle may be vertical, and the connection cavity 306 may be formed with a bend 324.

[0052] FIG7a depicts a cross-section of a casting of a cast component 300 around a portion of a core 210 held in the second mold half 206 after casting but before leaching according to aspects of the present subject matter. As shown in FIG7a, in some embodiments, the tie rods 214 are coils. It should be appreciated that additive manufacturing processes are particularly well suited for producing the core 210, particularly when the plurality of legs 212 and the plurality of tie rods 214 are made of the same material, and when at least one of the plurality of tie rods 214 is configured as a coil.

[0053] FIG. 7 b depicts a cross-section of the cast component 300 of FIG. 7 a after the core 210 is leached and removed from the second half 206 of the mold, according to aspects of the present subject matter. FIG. 7 b shows an exemplary embodiment in which the generated connecting cavity 306 is a hollow coil. With the coil construction, the connecting cavity 306 has a surface area greater than the surface area presented in a straight tie rod spanning the linear distance between the two legs 212. This increase in resistance hinders fluid communication through the connecting cavity 306. In addition, the coil construction can be oriented to counteract the Coriolis and centrifugal forces acting on the cooling fluid in certain cast components 300 of gas turbine aircraft engines.

[0054] FIG8a depicts a cross-section of a casting of a cast component 300 around a portion of a core 210 retained in the second half 206 of the mold after casting but before leaching, according to aspects of the present subject matter. As shown in FIG8a, in an alternative embodiment, the tie rod 214 can be configured to establish a venturi (i.e., a convergent-divergent tube section). When configured to establish a venturi, the tie rod 214 has a first diameter D1 and a second diameter D2. The first diameter D1 is positioned to contact the first tie rod end, and the second diameter D2 is located between the first diameter D1 and the second tie rod end 318. The first diameter D1 is greater than the second diameter D2. The second diameter D2 forms a restriction section or "choke" within the generated connecting cavity 306. The second diameter D2 is established at a position calculated to establish a restriction required to hinder fluid communication through the generated connecting cavity 306.

[0055] FIG8b depicts a cross section of the cast component 300 of FIG8a after the core 210 is leached and removed from the second half 206 of the mold according to aspects of the present subject matter. As shown in FIG8b, in an alternative embodiment, the connecting cavity 306 can be configured as a venturi tube. When configured as a venturi tube, the connecting cavity has a first diameter D1 and a second diameter D2. The first diameter D1 is greater than the second diameter D2. The second diameter D2 creates a restriction section or "choke" in the connecting cavity 306. When the fluid flows from the first diameter D1 to the second diameter D2, the velocity of the fluid increases, while its static pressure decreases. In this way, the second diameter D2 can be positioned at a position along the connecting cavity 306, at which the pressure in the connecting cavity first end 316 is equal to the pressure in the connecting cavity second end 318. It should be understood that there is no pressure difference between the connecting cavity ends 316, 318 that hinders the fluid communication through the connecting cavity.

[0056] FIG. 9a depicts a cross-section of a cast component 300 around a portion of a core 210 retained in a second mold half 206 after casting but before leaching, according to aspects of the present subject matter. As shown in FIG. 9a, in an alternative embodiment, the leachable casting core 210 includes a first material 226 that is susceptible to leaching, and the tie rods 214 include a second core material portion 224. The second core material portion 224 resists the leaching process used to remove the first leachable core material 226 from the cast component 300. For example, in certain embodiments, the core 210 can be additively manufactured such that the first core material 226 is a ceramic and the second core material portion 224 is a metal. Alternatively, the first core material 226 can be a metal and the second core material portion 224 is a ceramic. In some embodiments, the second non-leachable core material portion 224 can be a portion of the same material that comprises the cast component 300. Because the second non-leachable core material portion 224 is not removed from the cast component 300 by leaching, the second non-leachable core material portion 224 is an impediment to fluid communication through the generated connecting cavity 306.

[0057] FIG9b depicts a cross-section of the cast component 300 of FIG9a after the core 210 has been leached and removed from the mold second half 206, according to aspects of the present subject matter. As shown in FIG9b, a portion of the tie rod 214 remains secured within the connecting cavity 306 after the leaching process used to remove the first leachable core material 226 from the cast component 300. Because the second non-leachable core material portion 224 is not removed from the cast component 300 by leaching, the second non-leachable core material portion 224 is an impediment to fluid communication through the resulting connecting cavity 306.

[0058] In general, the exemplary embodiments of the leachable core 210 described herein may be manufactured or formed using any suitable process. However, according to several aspects of the present subject matter, the leachable core 210 may be formed using an additive manufacturing process, such as a 3D printing process. Using such a process may allow the leachable core 210 to be integrally formed as a single, unitary component or any suitable number of subcomponents. In particular, the manufacturing process may allow the leachable core 210 to be integrally formed and include various features that are not possible using existing manufacturing methods. For example, the additive manufacturing methods described herein enable the manufacture of cores having unique features, configurations, thicknesses, materials, and orientations that are not possible using existing manufacturing methods. Some of these novel features are described herein.

[0059] As used herein, the terms "additive manufacturing" or "additive manufacturing techniques or processes" generally refer to a manufacturing process in which successive layers of material are placed upon one another to "build up" a three-dimensional component layer by layer. Successive layers are typically fused together to form an integral component, which may have various integral subcomponents. Although the additive manufacturing techniques described herein are used to manufacture complex objects by typically building the object point-to-point, layer by layer in a vertical direction, other manufacturing methods are possible and within the scope of the present subject matter. For example, although the discussion herein relates to adding material to form successive layers, those skilled in the art will appreciate that the methods and structures disclosed herein may be implemented with any additive manufacturing technique or manufacturing technology. For example, embodiments of the present invention may use an additive layer process, a subtractive layer process, or a hybrid process.

[0060] Suitable additive manufacturing techniques according to the present disclosure include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing such as by inkjet, laser jetting and binder jetting, stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net shaping (LENS), laser net shape manufacturing (LNSM), direct metal deposition (DMD), digital light processing (DLP), direct selective laser melting (DSLM), selective laser melting (SLM), direct metal laser melting (DMLM) and other known processes.

[0061] The additive manufacturing processes described herein can be used to form parts using any suitable material. For example, the material can be plastic, metal, concrete, ceramic, polymer, epoxy resin, photopolymer resin, wax, or any other suitable material. These materials are examples of materials suitable for the additive manufacturing processes described herein and can generally be referred to as "additive materials."

[0062] In addition, those skilled in the art will appreciate that various materials and methods for combining these materials may be used and are contemplated to be within the scope of the present disclosure. As used herein, reference to "fusion" may refer to any suitable process for creating a bonded layer of any of the above-described materials. For example, if the object is made of a polymer, fusion may refer to creating a thermosetting bond between the polymer materials. If the object is an epoxy resin, the bond may be formed by a cross-linking process. If the material is a ceramic, the bond may be formed by a sintering process. If the material is a powdered metal, the bond may be formed by a melting or sintering process. Those skilled in the art will appreciate that other methods of fusing materials to make parts by additive manufacturing are possible, and those methods may be used to practice the subject matter currently disclosed.

[0063] In addition, the additive manufacturing processes disclosed herein allow a single component to be formed from a variety of materials. Thus, the components described herein can be formed from any suitable mixture of the above materials. For example, a component may include multiple layers, segments, or parts formed using different materials, processes, and / or on different additive manufacturing machines. In this way, components with different materials and material properties can be constructed to meet the needs of any application. In addition, although the components described herein are constructed entirely by additive manufacturing processes, it should be understood that in alternative embodiments, all or a portion of these components can be formed via casting, machining, and / or any other suitable manufacturing process. In fact, any suitable combination of materials and manufacturing methods can be used to form these components.

[0064] An exemplary additive manufacturing process will now be described. The additive manufacturing process uses three-dimensional (3D) information of a component, such as a three-dimensional computer model, to manufacture the component. Thus, a three-dimensional design model of the component can be defined prior to manufacturing. In this regard, a model or prototype of the component can be scanned to determine the three-dimensional information of the component. As another example, a model of the component can be constructed using a suitable computer-aided design (CAD) program to define, for example, Fig.13 3D design model of the component shown.

[0065] The design model can include 3D digital coordinates of the entire configuration of the component, including both the exterior and interior surfaces of the component. For example, the design model can define the body, surfaces and / or internal passages, such as openings, support structures, etc. In an exemplary embodiment, the three-dimensional design model is converted into multiple slices or segments, such as along the central (e.g., vertical) axis of the component or any other suitable axis. Each slice can define a thin cross-section of the component for a slice of a predetermined height. Multiple consecutive cross-sectional slices together form a 3D component. The component is then "stacked" piece by piece or layer by layer until it is completed.

[0066] In this manner, additive processes may be used to manufacture the components described herein, or more specifically, to successively form each layer, such as by fusing or polymerizing plastics using laser energy or heat, or by sintering or melting metal powders. For example, a particular type of additive manufacturing process may use an energy beam, such as an electron beam or electromagnetic radiation such as a laser beam, to sinter or melt powdered materials. Any suitable laser and laser parameters may be used, including considerations regarding power, laser beam spot size, and scan speed. The build material may be formed of any suitable powder or material selected for enhanced strength, durability, and service life, particularly at high temperatures.

[0067] Although the thickness can be selected based on any number of parameters, and can be any suitable dimension according to alternative embodiments, each successive layer can be, for example, between about 10 μm and 200 μm. Thus, using the above-described additive forming methods, the parts described herein can have a cross-section as thin as one thickness (e.g., 10 μm) of the associated powder layer used during the additive forming process.

[0068] In addition, using additive processing, the surface finish and characteristics of the component can be varied as desired depending on the application. For example, the surface finish can be adjusted (e.g., made smoother or rougher) by selecting appropriate laser scanning parameters (e.g., laser power, scanning speed, laser focal spot size, etc.) during the additive process, especially in the periphery of the cross-sectional layer corresponding to the surface of the part. For example, a rougher finish can be obtained by increasing the laser scanning speed or reducing the size of the formed molten pool, and a smoother finish can be achieved by reducing the laser scanning speed or increasing the size of the formed molten pool. The scanning pattern and / or laser power can also be changed to change the surface finish in the selected area.

[0069] It is noteworthy that in exemplary embodiments, several features of the components described herein were not previously possible due to manufacturing limitations. However, the inventors of the present invention have advantageously utilized recent advances in additive manufacturing technology to develop exemplary embodiments of such components generally in accordance with the present disclosure. Although the present disclosure is generally not limited to the use of additive manufacturing to form these components, additive manufacturing does provide various manufacturing advantages, including ease of manufacturing, reduced costs, greater accuracy, etc.

[0070] In this regard, even multi-part components can be formed as a single piece of continuous metal using additive manufacturing methods, and thus can include fewer sub-components and / or joints than existing designs. The integrated formation of these multi-part components through additive manufacturing can advantageously improve the overall assembly process. For example, the integrated formation reduces the number of separate parts that must be assembled, thereby reducing the associated time and overall assembly cost. In addition, existing issues such as leakage, joint quality between separate parts, and overall performance can be advantageously reduced.

[0071] Additionally, the additive manufacturing methods described above enable more complex and intricate shapes and contours of the components described herein. Furthermore, the additive manufacturing process enables the manufacture of a single component with different materials, such that different portions of the component can exhibit different performance characteristics. The continuous additive nature of the manufacturing process enables the construction of these novel features. As a result, the components described herein can achieve more intricate internal cast component shapes.

[0072] Reference now Fig.11, presents a flow chart of a method (500) for casting a component having multiple internal flow channels. The exemplary method (500) includes, at 502, positioning a core within a mold. For example, the mold may define an external component shape, wherein the core defines an internal component shape. The core may include a plurality of legs and at least one tie rod, the tie rod coupling at least two of the plurality of legs together. The exemplary method (500) includes, at 504, casting the component using the core and the mold. At 506, the exemplary method (500) includes removing the component from the mold. Additionally, the exemplary method (500) includes, at 508, leaching the core from the internal component shape. For example, leaching the plurality of legs may form at least a first internal flow channel and a second internal flow channel within the component. Leaching at least one tie rod may also form a plurality of connecting cavities, at least one of the plurality of connecting cavities having a connecting cavity first end and a connecting cavity second end. The plurality of connecting cavities may obstruct fluid communication through the plurality of connecting cavities.

[0073] Reference now Fig.12 , presents a flow chart of a method (600) for making a leachable casting core having a plurality of legs and fluid-impeding tie rods. The exemplary method (600) includes, at 602, depositing a layer of additive material on a bed of an additive manufacturing machine, and, at 604, selectively directing energy from an energy source onto the layer of additive material to fuse a portion of the additive material and form a leachable casting core. The leachable casting core of 604 includes a plurality of legs and a plurality of tie rods, the plurality of legs having an external shape that is a negative of at least a first flow channel and a second flow channel of a casting component, and the plurality of tie rods having a first tie rod end and a second tie rod end. The plurality of tie rods may be coupled to at least two of the plurality of legs, and the plurality of tie rods may have a negative shape of an impediment to fluid communication within the casting component.

[0074] Reference now Fig.13, presents a flow chart of a method (700) for designing a leachable casting core having a plurality of legs and fluid-impeding tie rods. The exemplary method (700) includes, at 702, obtaining, by a computing system including one or more computing devices, data indicating a first three-dimensional model of a leachable casting core. The casting core includes a plurality of legs, the plurality of legs being oriented to form at least a first internal flow channel and a second internal flow channel within the casting component. At 704, obtaining, by the computing system, data indicating a number and connection position information of a plurality of tie rods to fix an orientation of the plurality of legs. The plurality of tie rods include a first tie rod end, a second tie rod end, and a negative shape of an impediment to fluid communication within the casting component. Once the number and position of the legs and tie rods have been determined, the exemplary method (700) includes, at 706, generating, by the computing system, a second three-dimensional model based at least in part on the first three-dimensional model of the casting core and the number and connection position information of the plurality of tie rods. The second three-dimensional model represents a leachable casting core including a plurality of tie rods. The plurality of tie rods fix an orientation of the plurality of legs. At 708, the exemplary method (700) includes determining, by the computing system, a plurality of slices based at least in part on the second three-dimensional model. Each slice of the plurality of slices defines a respective cross-sectional layer of the leachable casting core. The exemplary method (700) includes, at 710, outputting, by the computing system, data indicating the plurality of slices to a memory.

[0075] Reference again Figure 1 In general, the engine 100 may include a core gas turbine engine (generally represented by reference character 114) and a fan section 116 located upstream thereof. The core engine 114 may generally include a substantially tubular casing 118 that defines an annular inlet 120. In addition, the casing 118 may further surround and support a booster compressor 122 for increasing the pressure of air entering the core engine 114 to a first pressure level. The high-pressure multi-stage axial compressor 124 may then receive the pressurized air from the booster compressor 122 and further increase the pressure of such air. The pressurized air leaving the high-pressure compressor 124 may then flow to a combustor 126, within which fuel is injected into the pressurized air flow by a fuel system 162, wherein the resulting mixture is combusted within the combustor 126. The high energy combustion products are directed from the combustor 126 along the hot gas path of the engine 100 to a first (high pressure HP) turbine 128 for driving the high pressure compressor 124 via a first (high pressure HP) drive shaft 130, and then to a second (low pressure LP) turbine 132 for driving the boost compressor 122 and the fan section 116 via a second (low pressure LP) drive shaft 134, which is generally coaxial with the first drive shaft 130. After driving each turbine 128 and 132, the combustion products may be exhausted from the core engine 114 via an exhaust nozzle 136 to provide propulsive jet thrust.

[0076] It should be understood that each turbine 128, 130 may generally include one or more turbine stages, wherein each stage includes a turbine nozzle and a downstream turbine rotor. As described below, the turbine nozzle may include a plurality of vanes disposed in an annular array about the centerline axis 112 of the engine 100 for rotating or otherwise directing the flow of combustion products through the turbine stages toward a corresponding annular array of rotor blades forming a portion of the turbine rotor. As generally understood, the rotor blades may be coupled to a rotor disk of the turbine rotor, which in turn is rotationally coupled to a drive shaft of the turbine (e.g., drive shaft 130 or 134).

[0077] In addition, if Figure 1 As shown, the fan section 116 of the engine 100 can generally include a rotatable axial flow fan rotor 138, which is configured to be surrounded by an annular fan housing 140. In a particular embodiment, the (LP) drive shaft 134 can be directly connected to the fan rotor 138, for example in a direct drive configuration. In an alternative configuration, the (LP) drive shaft 134 can be connected to the fan rotor 138 via a reduction gear 137, such as a reduction gearbox of an indirect drive or gear transmission configuration. Such a reduction gear can be included between any suitable shafts / spools within the engine 100 as desired or required.

[0078] Those skilled in the art will appreciate that the fan case 140 may be configured to be supported relative to the core engine 114 via a plurality of substantially radially extending circumferentially spaced outlet guide vanes 142. As such, the fan case 140 may surround the fan rotor 138 and its corresponding fan rotor blades 144. Additionally, a downstream section 146 of the fan case 140 may extend over an outer portion of the core engine 114 to define a secondary or bypass airflow duct 148 that provides additional propulsive jet thrust.

[0079] During operation of the engine 100, it should be appreciated that an initial airflow (indicated by arrow 150) may enter the engine 100 through an associated inlet 152 of the fan case 140. The airflow 150 then passes through the fan blades 144 and is split into a first compressed airflow (indicated by arrow 154) and a second compressed airflow (indicated by arrow 156), the first compressed airflow moving through the duct 148 and the second compressed airflow entering the boost compressor 122. The pressure of the second compressed airflow 156 is then increased and enters the high pressure compressor 124 (as indicated by arrow 158). After mixing with the fuel and combusting within the combustor 126, the combustion products 160 exit the combustor 126 and flow through the first turbine 128. Thereafter, the combustion products 160 flow through the second turbine 132 and exit the exhaust nozzle 136, thereby providing thrust to the engine 100.

[0080] Fig.10 A block diagram of an example computing system 400 is provided, which represents an embodiment that can be used to implement the methods and systems described in this article according to the exemplary embodiments of the present disclosure. As shown, the computing system 400 may include one or more computing devices 402. The one or more computing devices 402 may include one or more processors 404 and one or more memory devices 406. The one or more processors 404 may include any suitable processing device, such as a microprocessor, a microcontroller, an integrated circuit, a logic device, or other suitable processing device. The one or more memory devices 406 may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, hard disk drives, flash drives, or other memory devices.

[0081] The one or more memory devices 406 may store information accessible by the one or more processors 404, including computer readable instructions 408 that may be executed by the one or more processors 404. The instructions 408 may be any set of instructions that, when executed by the one or more processors 404, cause the one or more processors 404 to perform operations. The instructions 408 may be software written in any suitable programming language, or may be implemented in hardware. In some embodiments, the instructions 408 may be executed by the one or more processors 404 to cause the one or more processors 404 to perform a process for designing a leachable casting core, Fig.13 or a process for implementing any other process described herein.

[0082] The memory device 404 may further store data 410 that may be accessed by the processor 404. For example, the data 410 may include data indicating a leachable core material, a number of legs, an orientation of legs, a number of tie rods, tie rod connection points, or a configuration of tie rods as described herein. According to example embodiments of the present disclosure, the data 410 may include one or more tables, functions, algorithms, models, equations, and the like.

[0083] The computing device(s) 402 may also include a communication interface 412 for communicating with other components of the system, for example. The communication interface 412 may include any suitable components for interfacing with one or more networks, including, for example, a transmitter, receiver, port, controller, antenna, or other suitable components.

[0084] The techniques discussed herein refer to computer-based systems, as well as actions taken by computer-based systems and information sent to and from computer-based systems. It will be appreciated by those of ordinary skill in the art that the inherent flexibility of computer-based systems allows for various possible configurations, combinations, and divisions of tasks and functions between and within components. For example, the processing discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memories, instructions, and applications can be implemented on a single system or distributed on multiple systems. Distributed components can operate sequentially or in parallel.

[0085] This written description uses exemplary embodiments to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system, and performing any combined method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims, these other examples are intended to be within the scope of the claims.

[0086] Further aspects of the invention are provided by the subject matter of the following clauses:

[0087] 1. A casting component of a gas turbine aircraft engine, comprising: a body, the body defining: a plurality of internal flow passages, the plurality of internal flow passages further comprising a first internal flow passage and a second internal flow passage, and a plurality of connecting cavities, the plurality of connecting cavities having a connecting cavity first end connected to the fluid of the first internal flow passage and a connecting cavity second end opposite to the connecting cavity first end connected to the fluid of the second internal flow passage, the plurality of connecting cavities being configured to hinder fluid communication between the first internal flow passage and the second internal flow passage through the plurality of connecting cavities.

[0088] 2. A cast component according to any of the preceding clauses, further comprising: a portion of the first internal flow channel including a first turbulator, the first turbulator having an upstream first turbulator face and a downstream first turbulator face opposite to the upstream first turbulator face, the downstream first turbulator face defining a leading edge of a first low-pressure region within the first internal flow channel; a portion of the second internal flow channel including a second turbulator, the second turbulator having an upstream second turbulator face and a downstream second turbulator face opposite to the upstream second turbulator face, the downstream second turbulator face defining a leading edge of a second low-pressure region within the second internal flow channel; and wherein the first end of the connecting cavity is fluidically connected to the first low-pressure region, and the second end of the connecting cavity is fluidically connected to the second low-pressure region.

[0089] 3. A cast component according to any of the preceding clauses, wherein the first fluid flow channel restricts a first fluid flow and the second fluid flow channel restricts a second fluid flow, the first fluid flow has a pressure greater than a pressure of the second fluid flow, the component further comprising: a portion of the first internal flow channel including a first turbulator, the first turbulator having an upstream first turbulator face and a downstream first turbulator face opposite to the upstream first turbulator face, the downstream first turbulator face defining a leading edge of a first low-pressure region within the first internal flow channel; a portion of the second internal flow channel including a second turbulator, the second turbulator having an upstream second turbulator face and a downstream second turbulator face opposite to the upstream second turbulator face; and wherein the first end of the connecting cavity is fluidly connected to the first low-pressure region, and the second end of the connecting cavity is fluidly connected to the upstream second turbulator face.

[0090] 4. A cast component according to any of the preceding clauses, wherein the first end of the connecting cavity is connected to the first internal flow channel at an acute angle, and the second end of the connecting cavity is connected to the second internal flow channel at an acute angle, and at least one connecting cavity of the plurality of connecting cavities further includes a bend.

[0091] 5. A cast component according to any preceding clause, wherein at least one connecting cavity of said plurality of connecting cavities comprises a coil.

[0092] 6. A cast component according to any preceding clause, wherein a portion of at least one connecting cavity of said plurality of connecting cavities is obstructed by a non-leachable plug.

[0093] 7. A cast component according to any preceding clause, wherein the obstruction to fluid communication is a bend, a low pressure area, a pressure balance, reverse rotation or a physical obstruction.

[0094] 8. A method for casting a component having a plurality of internal flow passages, the method comprising: positioning a core within a cavity of a mold, wherein the cavity of the mold defines an external component shape, the core comprising a plurality of legs and at least one tie rod, the at least one tie rod coupling at least two of the plurality of legs together; casting the component within the cavity of the mold with the core positioned therein; removing the component from the mold with the core positioned internally within the component; and leaching the core from the component such that each of the plurality of legs forms a corresponding internal flow passage within the component, and wherein leaching the at least one tie rod forms a corresponding connecting cavity having a first end and a second end, and wherein each connecting cavity obstructs fluid communication through the connecting cavity.

[0095] 9. A method according to any of the preceding clauses, wherein each of the plurality of legs has a plurality of turbulator forming members, wherein the turbulator forming members have an upstream turbulator surface and a downstream turbulator surface opposite to the upstream turbulator surface, the downstream turbulator surface defining a leading edge of a low-pressure region within a corresponding flow channel, and wherein the at least one connecting cavity is fluidically connected to the low-pressure region.

[0096] 10. A method according to any of the preceding clauses, wherein: a first fluid flow channel restricts a first fluid flow, and a second fluid flow channel restricts a second fluid flow, the second fluid flow having a pressure less than a pressure of the first fluid flow; each of the plurality of legs has a plurality of turbulator forming members, wherein the turbulator forming members have an upstream turbulator surface and a downstream turbulator surface opposite to the upstream turbulator surface, the downstream turbulator surface defining a leading edge of a low-pressure region within a corresponding flow channel; and the first end is fluidically connected to the low-pressure region of the first fluid flow path, and the second end is fluidically connected to the upstream turbulator surface of the second fluid flow channel.

[0097] 11. A method according to any of the preceding items, wherein: the first internal flow channel has a first channel outer surface, and the second internal flow channel has a second channel outer surface; the first end of the connecting cavity intersects with the first internal flow channel outer surface at an acute angle; the second end of the connecting cavity intersects with the second internal flow channel outer surface at an acute angle; and the connecting cavity has a curved portion.

[0098] 12. The method according to any preceding clause, wherein at least one tie rod of the plurality of tie rods is formed as a coil.

[0099] 13. According to any method of the preceding clause, the connecting cavity has a first diameter and a second diameter, the first diameter is larger than the second diameter, and the second diameter establishes a limiting point in the connecting cavity, and the limiting point is located at a point along the connecting cavity calculated to make the pressure at the first end of the connecting cavity equal to the pressure at the second end of the connecting cavity.

[0100] 14. A method according to any of the preceding clauses, wherein the core further comprises a first core material susceptible to leaching treatment, the method further comprising inserting a second core material resistant to the leaching treatment into a portion of at least one of the plurality of tie rods, the second core material remaining in the component after the leaching treatment.

[0101] 15. A method according to any preceding clause, wherein the core is produced by additive manufacturing.

[0102] 16. The method according to any preceding clause, wherein the cast component is a component of a gas turbine aircraft engine.

[0103] 17. The method of any preceding clause, wherein said component is a turbine blade and said plurality of internal flow passages are a plurality of serpentine cooling passages.

[0104] 18. An intermediate cast component of a gas turbine aircraft engine, comprising: a casting body, the casting body comprising a first material; and a core, the core being within the casting body and comprising a second material that is susceptible to leaching, the core further comprising: a plurality of legs, the plurality of legs being oriented to form at least a first internal flow channel and a second internal flow channel within the component, and a plurality of tie rods, the plurality of tie rods being connected to at least two of the plurality of legs, at least one of the plurality of tie rods being oriented to form a connecting cavity, the configuration of the connecting cavity being an obstruction to fluid communication between the first internal flow channel and the second internal flow channel.

[0105] 19. An intermediate cast component according to any of the preceding clauses, wherein the plurality of legs further include a plurality of turbulator forming members, the turbulator forming members having an upstream turbulator surface and a downstream turbulator surface opposite to the upstream turbulator surface, the downstream turbulator surface defining a leading edge of a low pressure region within the plurality of internal flow channels, and wherein the plurality of connecting cavities are fluidly connected to the low pressure region.

[0106] 20. An intermediate cast component according to any of the preceding clauses, wherein the plurality of legs further include a plurality of turbulator forming members, the turbulator forming members having an upstream turbulator surface and a downstream turbulator surface opposite to the upstream turbulator surface, the downstream turbulator surface defining a leading edge of a low pressure region within the plurality of internal flow channels, and wherein the plurality of connecting cavities are fluidly connected to the low pressure region of the first internal flow channel and the upstream turbulator surface of the second internal flow channel.

Claims

1. An intermediate casting component, characterized in that: include: a casting body comprising a first material; and a core within the casting body and comprising a first core material susceptible to leaching treatment, the core further comprising: a plurality of legs oriented to form a plurality of internal flow passages within the cast component, and a plurality of tie rods having a first tie rod end and a second tie rod end, the plurality of tie rods being coupled to at least two of the plurality of legs, at least one tie rod of the plurality of tie rods being oriented to form a connecting cavity, the connecting cavity being configured to be an impediment to fluid communication between the plurality of internal flow passages, and wherein the connecting cavity serves as an impediment to fluid communication through the connecting cavity, wherein at least one of: The plurality of legs further include at least two cavity obstructions having an upstream face and a downstream face opposite the upstream face, and wherein the first tie rod end faces the first downstream face and the second tie rod end faces the second downstream face or the second upstream face; At least one of the plurality of tie rods is formed as a coil; or The core further comprises a second core material that is resistant to the leaching process, and wherein at least a portion of the at least one tie rod of the plurality of tie rods comprises the second core material.

2. The intermediate casting component according to claim 1, characterized in that The core is produced by additive manufacturing.

3. The intermediate casting component according to claim 1, characterized in that The cast component is a component of a gas turbine aircraft engine.

4. The intermediate casting component according to claim 3, characterized in that Wherein the component is a turbine blade and the plurality of internal flow passages are a plurality of serpentine cooling passages.

5. The intermediate casting component according to claim 1, characterized in that Wherein the core is ceramic.

6. The intermediate cast component according to claim 1, characterized in that Wherein the at least one tie rod comprises a plurality of bends that position the at least one tie rod of the plurality of tie rods in a "W", "U" or "S" configuration.

7. The intermediate casting component according to claim 1, characterized in that The at least one tie rod comprises a plurality of bends that are asymmetric in both magnitude and distribution along the at least one tie rod among the plurality of tie rods.

8. An intermediate casting component, characterized in that: include: a casting body comprising a first material; and a core within the casting body and comprising a first core material susceptible to leaching treatment, the core further comprising: a plurality of legs oriented to form a plurality of internal flow passages within the cast component, and a plurality of tie rods having a first tie rod end and a second tie rod end opposite the first tie rod end, the plurality of tie rods being coupled to at least two of the plurality of legs, wherein at least one of the plurality of tie rods is oriented to form a connecting cavity within the cast component between the plurality of internal flow passages, and wherein the configuration of the connecting cavity serves as an impediment to fluid communication through the connecting cavity, wherein the connecting cavity has a first diameter and a second diameter, the first diameter being greater than the second diameter, the second diameter establishing a restriction point within the connecting cavity, the restriction point being located at a point along the connecting cavity calculated to equalize a pressure at the first end of the connecting cavity with a pressure at the second end of the connecting cavity.

9. The intermediate cast component according to claim 8, characterized in that The core is produced by additive manufacturing.

10. The intermediate cast component according to claim 8, characterized in that The cast component is a component of a gas turbine aircraft engine.

11. The intermediate cast component according to claim 10, characterized in that Wherein the component is a turbine blade and the plurality of internal flow passages are a plurality of serpentine cooling passages.

12. The intermediate cast component according to claim 8, characterized in that Wherein the core is ceramic.

13. The intermediate cast component according to claim 8, characterized in that Wherein at least one of the plurality of tie rods comprises a plurality of bends that position the at least one tie rod in a "W", "U" or "S" configuration.

14. The intermediate cast component according to claim 8, characterized in that At least one of the plurality of tie rods comprises a plurality of bends, wherein the plurality of bends are asymmetric in both amplitude and distribution along the at least one tie rod.

15. An intermediate casting component, characterized in that: include: Casting body; and A core, the core being within the casting body, the core comprising: a plurality of legs oriented to form a plurality of internal flow passages within the cast component, and A plurality of tie rods having a first tie rod end and a second tie rod end opposite the first tie rod end, the plurality of tie rods being coupled to at least two of the plurality of legs, wherein at least one of the plurality of tie rods is oriented to form a connecting cavity between the plurality of internal flow passages within the casting, and wherein the configuration of the connecting cavity serves as an impediment to fluid communication through the connecting cavity, wherein at least one of the plurality of tie rods is coupled to the first leg at an acute angle and to the second leg at an acute angle, the at least one tie rod comprising a plurality of bends comprising two or more convolutes formed within the connecting cavity.

16. The intermediate cast component according to claim 15, characterized in that The core is produced by additive manufacturing.

17. The intermediate cast component according to claim 15, characterized in that Wherein the cast component is a component of a gas turbine aircraft engine, and wherein the component is a turbine blade and the plurality of internal flow passages are a plurality of serpentine cooling passages.

18. The intermediate cast component according to claim 15, characterized in that Wherein the core is ceramic.

19. The intermediate cast component according to claim 15, characterized in that Wherein the plurality of bends positions the at least one tie bar among the plurality of tie bars into a "W" or "S" configuration.

20. The intermediate cast component according to claim 15, characterized in that The plurality of bends are asymmetric in both magnitude and distribution along the at least one tie bar among the plurality of tie bars.

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