Tortuous cooling passageway for engine component

One exemplary embodiment of this disclosure relates to a gas turbine engine including a component having a body. The body includes a tortuous cooling passageway, which provides a flow path extending between an inlet in a first surface of the body and an exit in a second surface of the body.

BACKGROUND

Gas turbine engines include blades configured to rotate and extract energy from hot combustion gases that are communicated through the gas turbine engine. An outer casing of the gas turbine engine may support one or more blade outer air seals (BOAS) that provide an outer radial flow path boundary for the hot combustion gases. BOAS may include cooling passageways configured to route a flow of cooling fluid therein. One known BOAS includes parallel cooling passageways extending between circumferential edges thereof.

SUMMARY

One exemplary embodiment of this disclosure relates to a gas turbine engine including a component having a body. The body includes a tortuous cooling passageway, which provides a flow path extending between an inlet in a first surface of the body and an exit in a second surface of the body.

In a further embodiment of any of the above, the flow path includes at least one bend between the inlet and the exit.

In a further embodiment of any of the above, the inlet is provided about an inlet axis.

In a further embodiment of any of the above, the tortuous cooling passageway is a three-dimensional spiral passageway, and the flow path moves progressively further away from the inlet axis as the flow path extends from the inlet to the exit.

In a further embodiment of any of the above, the tortuous cooling passageway is a Z-shaped passageway.

In a further embodiment of any of the above, the Z-shaped passageway includes three sloped portions, and each of the three sloped portions is successively spaced radially further from the first surface.

In a further embodiment of any of the above, the cooling passageway is an M-shaped passageway.

In a further embodiment of any of the above, the M-shaped passageway includes a first inlet and a second inlet converging to a single exit.

In a further embodiment of any of the above, the component includes a plurality of tortuous cooling passageways, and wherein borders of adjacent cooling passageways are aligned relative to one another in at least one direction.

In a further embodiment of any of the above, axial borders and circumferential borders of adjacent cooling passageways are aligned.

In a further embodiment of any of the above, the component is a blade outer air seal (BOAS), and wherein the second surface is positioned adjacent a tip of a rotor blade.

Another exemplary embodiment of this disclosure relates to a blade outer air seal (BOAS). The BOAS includes a body including a tortuous cooling passageway, which provides a flow path extending in each of a radial, axial, and circumferential direction.

In a further embodiment of any of the above, the body includes a first surface and a second surface, the flow path provided between an inlet in the first surface and an exit in a second surface.

In a further embodiment of any of the above, the BOAS includes at least one of a three-dimensional spiral passageway, a Z-shaped passageway, and an M-shaped passageway.

In a further embodiment of any of the above, the BOAS includes a plurality of three-dimensional spiral passageways, a plurality of Z-shaped passageways, and a plurality of M-shaped passageways.

In a further embodiment of any of the above, the plurality of Z-shaped and M-shaped passageways are provided adjacent edges of the BOAS to provide a perimeter, and wherein the plurality of three-dimensional spiral passageways are provided within the perimeter.

In a further embodiment of any of the above, the tortuous cooling passageway includes at least one of trip strips and pedestals therein.

Another exemplary embodiment of this disclosure relates to a casting article. The article includes a first portion providing a negative of an inlet, and a second portion providing a negative of an outlet. The second portion is spaced from the first portion. Further, a third portion provides a negative of a tortuous cooling passageway, with the third portion extending between the first portion and the second portion.

In a further embodiment of any of the above, the third portion includes a plurality of sloped portions, with each of the plurality of sloped portions successively spaced further away from the first portion. The third portion further includes a plurality of legs extending between adjacent ones of the plurality of sloped portions. Each of the plurality of legs are successively spaced further away from the first portion.

In a further embodiment of any of the above, the tortuous cooling passageway is one of a three-dimensional spiral passageway, a Z-shaped passageway, and an M-shaped passageway.

DETAILED DESCRIPTION

A mid-turbine frame58of the engine static structure36is arranged generally between the high pressure turbine54and the low pressure turbine46. The mid-turbine frame58further supports bearing systems38in the turbine section28as well as setting airflow entering the low pressure turbine46.

In one disclosed embodiment, the gas turbine engine20includes a bypass ratio greater than about ten (10:1) and the fan diameter is significantly larger than an outer diameter of the low pressure compressor44. It should be understood, however, that the above parameters are only exemplary of one embodiment of a gas turbine engine including a geared architecture and that the present disclosure is applicable to other gas turbine engines.

FIG. 2illustrates a portion62of a gas turbine engine, such as the gas turbine engine20ofFIG. 1. In this exemplary embodiment, the portion62represents the high pressure turbine54. However, it should be understood that other portions of the gas turbine engine20could benefit from the teachings of this disclosure, including but not limited to, the fan section22, the compressor section24and the low pressure turbine46.

In this exemplary embodiment, a rotor disk66(only one shown, although multiple disks could be axially disposed within the portion62) is mounted for rotation about the engine central longitudinal axis A. The portion62includes alternating rows of rotating blades68(mounted to the rotor disk66) and static vane assemblies70. The vane assemblies70each includes a plurality of vanes70A,70B that are supported within an outer casing69of the engine static structure36(FIG. 1).

Each blade68of the rotor disk66includes a blade tip68T at a radially outermost portion of the blade68. The rotor disk66is arranged such that the blade tips68T are located adjacent a blade outer air seal (BOAS) assembly72. The BOAS assembly72may find beneficial use in many industries including aerospace, industrial, electricity generation, naval propulsion, pumps for gas and oil transmission, aircraft propulsion, vehicle engines and stationary power plants.

The BOAS assembly72is disposed in an annulus radially between the outer casing69and the blade tip68T. The BOAS assembly72generally includes a support structure74and a multitude of BOAS segments76(only one shown inFIG. 2). For ease of reference, the individual BOAS segments76are each individually referred to as a “BOAS segment” or simply a “BOAS.”

The BOAS segments76may be arranged to form a full ring hoop assembly that circumferentially surrounds the associated blades68. The support structure74is mounted radially inward from the outer casing69, and includes forward and aft flanges78A,78B that receive forward and aft attachment hooks76A,76B of the BOAS segments76. The forward and aft flanges78A,78B may be manufactured of a material such as a steel or nickel-based alloy, and may be circumferentially segmented for the receipt of the BOAS segments76.

A secondary cooling airflow S may be communicated to the BOAS segments76. The secondary cooling airflow S can be sourced from the high pressure compressor52or any other portion of the gas turbine engine20. In addition to providing a source of cooling air to the BOAS segment76, the secondary cooling airflow S provides a biasing force that biases the BOAS segment76radially inward toward the engine central longitudinal axis A. In one example, the forward and aft flanges78A,78B are portions of the support structure74that limit radially inward movement of the BOAS segment76and that maintain the BOAS segment76in position.

FIG. 3illustrates a perspective view of an example BOAS segment80according to this disclosure. While BOAS segments are discussed herein, it should be understood that this disclosure extends to other engine components, such as blades and vanes, as examples.

The BOAS segment80includes a fore edge82, an aft edge84, and a main body portion86extending axially (e.g., relative to the engine central longitudinal axis A, or the “axial direction A”) therebetween. The main body portion86includes a plurality of cooling passageways receiving a portion of the secondary cooling airflow S, as will be discussed in detail below. In this example, the BOAS segment80includes attachment hooks88,90,92,94,96,98,100, which extend upwardly from the main body portion86adjacent the aft edge84. The attachment hooks88,90,92,94,96,98,100are shown for illustrative purposes only and are not intended to limit this disclosure. The BOAS segment80further includes a first circumferential edge102, and a second circumferential edge104.

As illustrated inFIGS. 4A-4B, the main body portion86includes a radially outer surface106, and a radially inner surface108. The radially outer and inner surfaces106,108are spaced-apart from one another in the radial direction Z, which is normal to the engine central longitudinal axis A.

The main body portion86further includes a plurality of tortuous cooling passageways configured to communicate the secondary cooling air flow S between the radially outer and radially inner surfaces106,108. As used herein, the term “tortuous” refers to a cooling passageway that provides a flow path having at least one bend or turn between an inlet and an exit thereof. Several example tortuous cooling passageways are discussed herein.

A first example cooling passageway is illustrated at110. In the example, the cooling passageway110provides a three-dimensional spiral flow path112between the inlet114and the exit116in the radially inner surface108. In particular, the cooling passageway110is arranged such that the flow path112moves progressively farther away from an inlet axis118as the flow path112moves from the inlet114to the exit116.

As illustrated, the cooling passageway110is in fluid communication with the inlet114. The inlet114is provided about the inlet axis118, which in this example is arranged parallel to the radial direction Z. Moving radially inward from the inlet114, the cooling passageway110includes a first sloped portion120turning the flow path112from a generally radial direction Z to a generally axial direction A, and configured to direct a secondary cooling flow S toward a first leg122of the flow path112.

The first leg122extends in a circumferential direction Y, which is substantially normal to the axial direction A. The first leg122is in communication with a second sloped portion124, which runs substantially parallel to the first sloped portion120. The second sloped portion124leads to a second leg126, which extends in the circumferential direction Y and, in turn, leads to a third sloped portion128. Finally, the third sloped portion128extends in the axial direction A toward a third leg130, which extends circumferentially to a fourth sloped portion132. The fourth sloped portion132is in fluid communication with the exit116.

Each sloped portion120,124,128,132is inclined (or, angled) to extend non-parallel to the radially outer surface106to direct the secondary cooling flow S radially toward the exit116. That is, in the example ofFIGS. 4A-4B, as the secondary cooling flow S travels along each sloped portion120,124,128,132, the secondary cooling flow S travels both axially along the length of the particular sloped portion and radially toward the exit116. Accordingly, each successive sloped portion120,124,128,132is radially spaced (e.g., in the direction Z) further from the radially outer surface106than the prior sloped portion.

Further, in this example, each successive leg122,126,130is radially spaced further from the radially outer surface106than the prior leg. It should be understood that the legs122,126,130may also be sloped (e.g., inclined to extend non-parallel to the radially outer surface106) alternatively, or in addition to, the sloping of the sloped portions120,124,128,132.

It should further be understood that while four sloped portions120,124,128,132and three legs122,126,130are illustrated, the cooling passageway110could include any number of sloped portions and legs.

During operation, a portion of a secondary cooling flow S is routed into the cooling passageway110, and flows along the flow path112to cool the BOAS segment80. The secondary cooling flow S exits the cooling passageway110out the exit116, and generates a film providing additional sealing between the BOAS segment80the adjacent blade tips68T. The exit116may be shaped to provide a desired film.

FIG. 5schematically represents the cooling passageway110viewed from a location radially outboard of the radially outer surface106. As illustrated betweenFIGS. 4 and 5, the flow path112directs the secondary cooling flow S in three directions, radially (in direction Z) between the outer surface106, and the inner surface108, axially, via the sloped portions120,124,128,132, and circumferentially, by way of the legs122,126,130. This provides a relatively large effective cooling area in a relatively small three-dimensional space.

The main body portion86of the BOAS may include a plurality of the cooling passageways110positioned adjacent one another. For instance, as illustrated inFIG. 6, circumferential borders of adjacent passageways may be circumferentially aligned. That is, with reference toFIG. 6, the circumferential border of the fourth sloped portion132of the cooling passageway110A is spaced a circumferential distance D1from a circumferential border of the third sloped portion128of the adjacent cooling passageway110B. In one example, the distance D1is zero, in which case the circumferential borders of the cooling passageways110A,110B are circumferentially aligned. This relatively close packing between adjacent cooling passageways110A,110B is possible due to the third sloped portion132being radially spaced from the second sloped portion128, as described above.

Likewise, axial borders of adjacent cooling passageways may be axially aligned. For instance, the axial border of the second leg126of the cooling passageway110A is spaced a circumferential distance D2from an axial border of the third leg130of an adjacent cooling passageway110C. The distance D2is zero in one example, in which case the axial borders of the cooling passageways110A,110C are axially aligned. Again, this close packing is possible because the legs126and130are radially spaced apart from one another.

While a three-dimensional spiral passageway is illustrated inFIGS. 5-6, this disclosure extends to other types of cooling passageways. For instance,FIG. 7illustrates Z-shaped passageways134. The Z-shaped cooling passageways134include an inlet136and a plurality of sloped portions138,140, and142. The sloped portions, like the above-discussed sloped portions, are inclined to extend non-parallel to the radially outer surface106. The sloped portions138,140,142direct a secondary cooling airflow S in both an axial direction A and a radial direction A toward an exit137.

The Z-shaped passageways further include a first leg144extending circumferentially between the first and second sloped portions138,140, and a second leg146extending circumferentially between the second sloped portion140and the third sloped portion142. As mentioned above relative to the embodiment ofFIGS. 4-5, the first and second legs144,146may also be sloped.

FIG. 8illustrates another cooling passageway148. In this example, the cooling passageway148is an M-shaped cooling passageway. The cooling passageway148includes a first inlet150, a second inlet152, and a common exit154. As a flow of fluid enters the first inlet150, it is directed along a first sloped portion156, turned circumferentially at a first leg158, and directed along a second sloped portion160. Another, separate flow similarly travels from the first inlet152, where it converges with flow from the first inlet150at a third, common sloped portion162, which finally directs the converging flows from the first and second inlets150,152to a common exit154in the radially inner surface108.

It should be understood that the main body portion86may include one or more different cooling passageways. For instance, one example layout is illustrated inFIG. 9. In this example, the main body portion86includes a plurality of Z-shaped passageways134along both the fore and aft edges82,84thereof. The circumferential edges102,104in this example include M-shaped cooling passageways148. The Z-shaped and M-shaped passageways134,148define a perimeter adjacent the outer edges of the main body portion86.

A plurality of three-dimensional spiral passageways110are provided within the perimeter of Z-shaped and M-shaped passageways134,148. The illustrated arrangement is particularly beneficial because it provides the inlets to each of the passageways110,134,148at a point that is spaced inward from one of the edges82,84,102,104. This inward spacing of the inlets allows for a clearance between the inlets and the adjacent engine and BOAS structures (e.g., such as the attachment hooks88,90,92,94,96,98,100inFIG. 3) which may interfere with the secondary cooling flow S.

Additional tortuous cooling passageways are contemplated within the scope of this disclosure.FIG. 10Aillustrates a divergent cooling passageway164which has an inlet166and a divider wall168downstream therefrom which separates a flow of fluid into two parallel flows moving along parallel sloped passageways170,172. The passageways170,172then merge and exit out the exit174.

FIG. 10Billustrates a U-shaped cooling passageway176. The cooling passageway176includes an inlet178, a first sloped portion180, a first leg182and a second sloped portion184which leads to an exit186.

Still another example is illustrated inFIG. 10C, which shows an angled cooling passageway181. The cooling passageway181includes an inlet183, a sloped portion185, and an angled portion187leading to an exit189. The angled portion187extends in a direction inclined relative to the radially outer surface106, and relative to the direction the sloped portion185extends. Again, while several example cooling passageways are illustrated, it should be understood that additional passageways come within the scope of this disclosure.

Further, it should be understood that features for enhanced cooling, such as trip strips188(FIG. 11A) or pedestals190(FIG. 11B) can be included in the cooling passageways for increased cooling, depending on a heat load, for example.

The cooling passageways described herein can be formed using any known technique. One known technique includes additive manufacturing. Another known technique includes investment casting. In the example where the passageways are formed using investment casting, a wax pattern of the BOAS segment80is formed. In the example, a casting article (e.g., a core insert) is provided into a die, and a wax pattern of the BOAS segment80is formed.

An example casting article192is illustrated inFIG. 12. The casting article192is a dimensional negative of the cooling passageway110.FIG. 12is labeled with numbers corresponding to the respective portions of the cooling passageway110, appended with a “C.” For the sake of brevity, the portions of the cooling passageway110described above will not be repeated herein relative to the casting article192.

The casting article192in this example is a refractory metal core (RMC) insert. In one example, the RMC core may be additively manufactured. In other examples, the article may be a ceramic insert. In either case, the casting article is provided in the wax pattern and remains part of the wax pattern until the component is cast. As is known in the art, the casting is completed, and the main body portion86is provided with the intended passageway.

While the terms “axial,” “circumferential,” “radial,” etc., are used throughout this disclosure to describe the arrangement of the various cooling passageways, it should be understood that these terms are used only for purposes of illustration, and should not otherwise be considered limiting.