Turbine engine

BACKGROUND

0001This application relates generally to an arrangement of gas turbine engine components that facilitates sealing a turbine engine.

0002Gas turbine engines are known and typically include multiple sections, such as a fan section, a compression section, a combustor section, a turbine section, and an exhaust nozzle section. The compressor and turbine sections include blade arrays mounted for a rotation about an engine axis. The blade arrays include multiple individual blades that extend radially from a mounting platform to a blade tip.

0003Rotating the blade arrays compresses air in the compression section. The compressed air mixes with fuel and is combusted in the combustor section. The products of combustion expand to rotatably drive blade arrays in the turbine section. The tips of the individual blades within the rotating blade arrays each establish a seal with another portion of the engine, such as an engine control ring or a blade outer air seal, at a seal interface. The sealing relationship between the individual blade and the other portion of the engine facilitates compression of the air and expansion of the products of combustion. Maintaining the integrity of the components near the sealing interface helps maintain the sealing relationship.

0004As known, cooling air removes thermal byproducts from the engine, but many components are still exposed to extreme temperatures and temperature variations. Exposing a single monolithic component to varied temperatures can result in uneven expansion of that component, which can affect the integrity of that component by, for example, disrupting the mounting of the component or causing the component to fracture. Disadvantageously, components made of materials capable of withstanding extremely high temperatures often fail when exposed to varied temperatures, and components made of materials capable of withstanding varied temperatures often fail when exposed to extreme temperatures.

0005A gas turbine engine and method of sealing a portion of such, with features of the preamble of claims 1 and 13, is disclosed in <patcit id="pcit0001" dnum="US5474417A"><text>US 5,474,417</text></patcit>. Other gas turbine engines and methods are disclosed in <patcit id="pcit0002" dnum="EP1832755A"><text>EP1832755</text></patcit>, <patcit id="pcit0003" dnum="US3085398A"><text>US3085398</text></patcit>, <patcit id="pcit0004" dnum="EP0719908A"><text>EP0719 908</text></patcit> and <patcit id="pcit0005" dnum="EP1582700A"><text>EP1582700</text></patcit>.

SUMMARY

0006From one aspect, the present invention provides a gas turbine engine in accordance with claim 1.

0007From another aspect, the present invention provides a method of sealing a portion of a turbine engine in accordance with claim 13.

BRIEF DESCRIPTION OF THE DRAWINGS

0008<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> shows a schematic view of an example gas turbine engine.</li><li><figref idref="f0001">Figure 2</figref> shows a perspective view of a portion of a sealing arrangement from the <figref idref="f0001">Figure 1</figref> engine.</li><li><figref idref="f0002">Figure 3</figref> shows an exploded view of a cladding and a seal from the <figref idref="f0001">Figure 2</figref> sealing arrangement.</li><li><figref idref="f0002">Figure 4</figref> shows a section view through the sealing arrangement portion of the <figref idref="f0001">Figure 1</figref> engine.</li><li><figref idref="f0002">Figure 5</figref> shows a section view at line 5-5 of <figref idref="f0002">Figure 4</figref> having a cutaway portion.</li><li><figref idref="f0003">Figure 6A</figref> shows a section view at line 6-6 of <figref idref="f0002">Figure 4</figref> showing an example cladding arrangement.</li><li><figref idref="f0003">Figure 6B</figref> shows a section view at line 6-6 of <figref idref="f0002">Figure 4</figref> showing an alternative cladding arrangement.</li><li><figref idref="f0003">Figure 6C</figref> shows a section view at line 6-6 of <figref idref="f0002">Figure 4</figref> showing another alternative cladding arrangement.</li><li><figref idref="f0003">Figure 6D</figref> shows a section view at line 6-6 of <figref idref="f0002">Figure 4</figref> showing yet another alternative cladding arrangement.</li><li><figref idref="f0003">Figure 7</figref> shows a perspective view of an alternative sealing arrangement from the <figref idref="f0001">Figure 1</figref> engine.</li></ul>

DETAILED DESCRIPTION

0009<figref idref="f0001">Figure 1</figref> schematically illustrates an example gas turbine engine 10 including (in serial flow communication) a fan section 14, a low-pressure compressor 18, a high-pressure compressor 22, a combustor 26, a high-pressure turbine 30, and a low-pressure turbine 34. The gas turbine engine 10 is circumferentially disposed about an engine centerline X. During operation, air is pulled into the gas turbine engine 10 by the fan section 14, pressurized by the compressors 18 and 22, mixed with fuel, and burned in the combustor 26. The turbines 30 and 34 extract energy from the hot combustion gases flowing from the combustor 26.

0010In a two-spool design, the high-pressure turbine 30 utilizes the extracted energy from the hot combustion gases to power the high-pressure compressor 22 through a high speed shaft 38. The low-pressure turbine 34 utilizes the extracted energy from the hot combustion gases to power the low-pressure compressor 18 and the fan section 14 through a low speed shaft 42. The examples described in this disclosure are not limited to the two-spool engine architecture described and may be used in other architectures, such as a single-spool axial design, a three-spool axial design, and still other architectures. That is, there are various types of engines that could benefit from the examples disclosed herein, which are not limited to the design shown.

0011Referring now to <figref idref="f0001 f0002">Figures 2-4</figref> with continuing reference to <figref idref="f0001">Figure 1</figref>, an example sealing arrangement 48 within the engine 10 includes a blade 50 having a blade tip portion 54 that is configured to seal against a cladding 58 carried by a control ring 62. A sealing interface 66 is established between the blade tip 54 and the cladding 58 when the blade tip 54 seals against the cladding 58. The cladding 58 includes a first outer tile 70, an inner tile 74, and a second outer tile 78.

0012In this example, the axial length of the sealing interface 66 generally corresponds to the axial length of the blade tip 54. The sealing interface 66 also axially extends from the first outer tile 70, across the inner tile 74, to the second outer tile 78. That is, the blade tip 54 is configured to establish the sealing interface 66 with cladding 58 having multiple individual tiles, rather than a single tile.

0013The example cladding 58 is ceramic. In another example, one or more of the first outer tile 70, the inner tile 74, or the second outer tile 78 have another composition, such as a ceramic matrix composite.

0014To hold the position of the cladding 58, the example cladding 58 slidingly engages the control ring 62. More specifically, in this example, the cladding 58 establishes a groove 82 that is operative to receive a corresponding extension 86 of the control ring 62. The first outer tile 70 and the second outer tile 78 further include a flange 90 directed radially outward that act as stops to limit axial movements of the cladding 58 relative to the control ring 62.

0015In this example, securing the cladding 58 relative to the control ring 62 involves first sliding the inner tile 74 axially such that the extension 86 of the control ring 62 is received within the groove 82 of the inner tile 74. Next, the control ring 62 is received within the groove 82 of the inner tile 74. Next, the first outer tile 70 and the second outer tile 78 are slid over corresponding portions of the extension 86.

0016As can be appreciated from the figures, the example extension 86 and the example groove 82 have a tongue and groove type relationship that limits relative radial movement between the cladding 58 and the control ring 62 when the extension 86 is received within the groove 82. In another example, the control ring 62 establishes a groove operative to receive an extension of the cladding.

0017Other portions of the engine 10, such as a vane section 94 upstream from the control ring 62 limit axial movement of the cladding 58 away from the control ring 62. In one example, a portion 98 of the engine 10 is spring loaded such that the portion 98 biases the cladding 58 in an upstream direction toward the vane section 94.

0018The example inner tile 74 and outer tiles 70 and 78 each include a surface 99 facing the blade tip 54 that is about 2-3 centimeters by 2-3 centimeters. The minimum depth of the inner tile 74 and outer tiles 70 and 78 is about 1 centimeter, for example.

0019In this example, a plurality of hangers 102 extend from an outer casing 106 of the engine 10 to hold the control ring 62 within the engine 10. The hangers 102 are circumferentially disposed about the control ring 62. In one example, the control ring 62 is made of a ceramic material. In another example, the control ring 62 comprises a ceramic metal composite. Cooling airflow moves between the outer casing 106 and the control ring 62 as is known.

0020Portions of the cladding 58 are radially spaced from the control ring 62 when the extension 86 is received within the groove 82 to provide a cleared area 100 between the control ring 62 and the cladding 58. In some examples, no cooling airflow near the sealing interface 66 is required, which forces the cladding 58 to operate in a higher temperature environment. The cladding 58 is still able to seal with the blade 50 in such an environment at least because the cladding 58 withstands the higher temperatures more effectively than a monolithic structure. In one example, cooling airflow moves to the cleared area 100 to cool the sealing interface 66, especially the cladding 58.

0021A seal plate 108 provides a seal near the cleared area 100 that blocks flow of air between the cleared area 100 and another portion of the engine 10. Compression forces within the engine 10 force the seal plate 108 radially inward against the control ring 62 and the cladding, which enhances the effectiveness of the associated seal. In one example, the seal is a cobalt alloy seal. Other examples may include a ceramic matrix composite seal.

0022In this example, the cladding 58 is arranged in axially extending rows 114 on the control ring 62. The example seal 108 extends axially to contact each of the first outer tile 70, the inner tile 74, and the second outer tile 78 of the cladding 58. The example rows 114 are circumferentially distributed around the control ring 62.

0023In the <figref idref="f0003">Figure 6A</figref> example, the inner tile 74 meets the first outer tile 70 and the second outer tile 78 at tile interfaces 126, which are aligned with the tile interfaces 126 of adjacent rows 114. In the <figref idref="f0003">Figure 6B</figref> example, some of the rows 114 include two inner tiles 74, and the tile interfaces 126 of adjacent rows 114 are staggered. In both the <figref idref="f0003">Figure 6A and 6B</figref> examples, the rows are generally aligned with the engine centerline X.

0024In the <figref idref="f0003">Figure 6C</figref> example, the rows 114 extend in an arc relative to the engine centerline X. In the <figref idref="f0003">Figure 6D</figref> example, the rows 114 are disposed at an angle θ relative to the engine centerline X. Other examples include other arrangements of the cladding 58.

0025As shown in <figref idref="f0003">Figure 7</figref>, in some examples, a plurality of clips 130 are secured to the control ring 136 and the cladding 58 is slidingly received over the clips 130, rather than the extension 86 (<figref idref="f0001">Figure 2</figref>) to hold the cladding 58 relative to the control ring 136.

0026Features of the disclosed examples include using cladding consisting of multiple tiles, to provide a sealing interface with a blade rather than a cladding consisting of a single monolithic structure that can crack in response to temperature variations. Another feature of the disclosed example is simplified method of securing the cladding relative to other portions of an engine. Yet another feature is to size the tiles such that internal flaws created during manufacturing are minimized, and process yields are increased.

0027Although an exemplary embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the appended claims.