Seal device and rotary machine

Abstract

This seal device comprises; a seal ring having a fin fixing surface; and a plurality of seal fins projecting from the fin fixing surface. The seal ring includes: a ring body to which the plurality of seal fins are fixed; a ring protruding wall that protrudes from an end of the ring body so as to approach the outer circumferential surface of the rotary shaft; and a ring through-hole that passes through the ring body in the radial direction. The ring protruding wall extends radially inward from the ring body past a position overlapping, in the radial direction, the position of a gap between the outer circumferential surface of the rotary shaft and the tips of the plurality of seal fins, so as to approach the outer circumferential surface of the rotary shaft.

Description

Seal device and rotating machine

[0001] This application claims priority to Japanese Patent Application No. 2024-071099, filed on April 25, 2024, the contents of which are incorporated herein by reference.

[0002] A seal device is disposed in rotary machines such as gas turbines and steam turbines to seal between a rotating shaft (rotor) and a stationary member (stator) that covers the rotating shaft. The seal device seals the space between the rotating shaft and the stationary member by dividing it into one side and the other side in the axial direction of the rotating shaft.

[0003] For example, in a two-shaft gas turbine described in Patent Document 1, a space between a rotating shaft and a stationary member is sealed by a seal having a plurality of fins.

[0004] Japanese Patent Application Laid-Open No. 2005-337082

[0005] In a sealing device having multiple fins, the gap between the tips of the fins and the outer circumferential surface of the rotating shaft is very narrow to ensure sealing performance. When a sealing device having such fins is placed in a high-pressure space, even a small amount of fluid leaks through the gap between the multiple fins and the outer circumferential surface of the rotating shaft and is ejected in the axial direction at high pressure. The jet stream ejected from the sealing device can become very hot depending on the temperature of the fluid. If other components are placed axially adjacent to the sealing device, they will be exposed to the high-temperature, high-pressure jet stream. As a result, the other components may experience large thermal stress and deformation. Therefore, it is desirable to reduce the pressure of the fluid ejected in the axial direction from the gap between the fins and the rotating shaft.

[0006] The present disclosure provides a seal device and a rotary machine that are capable of reducing the pressure of a fluid that is discharged axially from a gap between a fin and a rotary shaft.

[0007] A sealing device according to the present disclosure is a sealing device that seals between an outer peripheral surface of a rotating shaft and a stationary member arranged radially outward from the rotating shaft, and includes: a seal ring formed in an annular shape around a seal axis and having a fin fixing surface that faces the outer peripheral surface of the rotating shaft in the radial direction; and a plurality of seal fins formed in an annular shape around the seal axis and protruding from the fin fixing surface toward the outer peripheral surface of the rotating shaft, wherein the seal ring has a ring body to which the plurality of seal fins are fixed, a ring protruding wall that protrudes from an end of the ring body in the axial direction along which the seal axis extends so as to approach the outer peripheral surface of the rotating shaft, and a ring through hole that is formed in the axial direction at a position closer to the ring protruding wall than the seal fins and that penetrates the ring body in the radial direction, and the ring protruding wall extends radially inward from the ring body so as to approach the outer peripheral surface of the rotating shaft beyond a position that overlaps with the position of the gap between the outer peripheral surface of the rotating shaft and the tips of the plurality of seal fins.

[0008] In addition, the rotary machine according to the present disclosure comprises the sealing device, a rotating shaft whose outer peripheral surface is sealed by the sealing device, a stationary member to which the seal ring is fixed and which covers the rotating shaft, and a bearing device arranged alongside the sealing device in the axial direction and which rotatably supports the rotating shaft, and the ring protruding wall is arranged in a position close to the bearing device relative to the plurality of seal fins in the axial direction and in a position overlapping with the bearing device in the radial direction.

[0009] According to the seal device and rotary machine of the present disclosure, it is possible to reduce the pressure of the fluid that is discharged in the axial direction from the gap between the fin and the rotary shaft.

[0010] It is a schematic diagram showing a rotary machine according to the present embodiment. It is an enlarged view of a main part in which an area where a seal device and a bearing device are arranged in the rotary machine according to the present embodiment is enlarged. It is an enlarged view of a main part explaining the periphery of the seal device according to the present embodiment. It is a perspective view explaining a seal ring according to the present embodiment.

[0011] Hereinafter, an embodiment for carrying out the seal device 10 and the rotary machine according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to only this embodiment.

[0012] (Rotary Machine) The rotary machine in this embodiment is a two-shaft gas turbine 1. As shown in Figures 1 and 2, the two-shaft gas turbine 1 of this embodiment includes a compressor 2, a combustor 3, a high-pressure turbine 4, an intermediate shaft 6, a low-pressure turbine 5, a bearing device 7, an inner casing 8, an upstream seal unit 9, and a seal device 10.

[0013] The compressor 2 compresses air to generate compressed air. The compressor 2 has a compressor rotor 21 that rotates about a first axis O1 and a compressor casing 22 that covers the compressor rotor 21. The compressor 2 compresses air taken in from the outside by rotation of the compressor rotor 21 to generate compressed air and supplies the compressed air to the combustor 3. A compressor main flow path F1 is formed between the compressor rotor 21 and the compressor casing 22. Within the compressor main flow path F1, compressor stator vanes (not shown) fixed to the inner wall of the compressor casing 22 are arranged alternately with the compressor rotor blades 25 in the axial direction Da.

[0014] Here, the axial direction Da is the direction in which the first axis O1 extends. One side in the axial direction Da is referred to as the first side D1. The first side D1 is the side in the axial direction Da where the compressor 2 is disposed relative to the high-pressure turbine 4, and is the upstream side in the flow direction of the compressed air and combustion gas. The other side in the axial direction Da is referred to as the second side D2. The second side D2 is the side in the axial direction Da where the low-pressure turbine 5 is disposed relative to the high-pressure turbine 4, and is the downstream side in the flow direction of the compressed air and combustion gas.

[0015] The direction perpendicular to the first axis O1 and centered on the first axis O1 is referred to as the radial direction Dr. The direction around the first axis O1 is referred to as the circumferential direction Dc. Furthermore, the side of the radial direction Dr that approaches the first axis O1 is referred to as the inner side Dri of the radial direction Dr, and the side of the radial direction Dr that moves away from the first axis O1 is referred to as the outer side Dro of the radial direction Dr.

[0016] The combustor 3 generates combustion gas from the air compressed by the compressor 2 and fuel. The combustion gas generated in the combustor 3 is supplied to the high-pressure turbine 4.

[0017] The high-pressure turbine rotor 41 is rotationally driven by the combustion gas generated in the combustor 3. The high-pressure turbine 4 has the high-pressure turbine rotor 41 rotating about a first axis O1, and a high-pressure turbine casing 42 that covers the high-pressure turbine rotor 41. The high-pressure turbine rotor 41 is rotated relative to the high-pressure turbine casing 42 by the combustion gas. A gas path F2, through which the combustion gas from the combustor 3 passes, is formed between the high-pressure turbine rotor 41 and the high-pressure turbine casing 42. Within this gas path F2, turbine stator vanes 44 fixed to the inner wall of the high-pressure turbine casing 42 are arranged alternately with turbine rotor blades 45 in the axial direction Da.

[0018] The high-pressure turbine rotor 41 is coupled to an intermediate shaft 6 (rotating shaft). The intermediate shaft 6 is disposed between the compressor rotor 21 and the high-pressure turbine rotor 41. The intermediate shaft 6 is disposed between the compressor 2 and the high-pressure turbine 4 in the axial direction Da. The intermediate shaft 6 is disposed at a position overlapping the combustor 3 in the axial direction Da. The high-pressure turbine rotor 41 is mechanically coupled to the compressor rotor 21 via the intermediate shaft 6. The compressor rotor 21, the intermediate shaft 6, and the high-pressure turbine rotor 41 all have a cylindrical shape centered on a first axis O1. The compressor rotor 21, the intermediate shaft 6, and the high-pressure turbine rotor 41 are coupled to one another to form a first rotor R1. In other words, the compressor rotor 21 and the high-pressure turbine rotor 41 are coaxially coupled by the intermediate shaft 6 and rotate integrally. Therefore, the first rotor R1 is a rotating shaft that includes the intermediate shaft 6.

[0019] The low-pressure turbine 5 is rotationally driven by the combustion gas that has passed through the high-pressure turbine 4. Therefore, the low-pressure turbine 5 is driven by the combustion gas, which is the exhaust gas from the high-pressure turbine 4. The low-pressure turbine 5 has a low-pressure turbine rotor 51 that rotates about a second axis O2, and a low-pressure turbine casing 52 that covers the low-pressure turbine rotor 51. The second axis O2 extends coaxially and parallel to the first axis O1. That is, when viewed from the axial direction Da, the second axis O2 extends in the axial direction Da at the same position as the first axis O1. Therefore, the low-pressure turbine rotor 51 substantially rotates about the first axis O1. The low-pressure turbine rotor 51 is rotated relative to the low-pressure turbine casing 52 by the combustion gas that has rotationally driven the high-pressure turbine rotor 41. The low-pressure turbine rotor 51 is disposed apart from the high-pressure turbine rotor 41 in the axial direction Da. The low-pressure turbine rotor 51 is not in contact with the high-pressure turbine rotor 41. The low-pressure turbine rotor 51 is rotatable independently (for example, at a different rotation speed) from the high-pressure turbine rotor 41. The low-pressure turbine 5 is mechanically coupled to the rotor of the generator G to form a second rotor R2.

[0020] The first rotor R1 and the second rotor R2 are not directly connected, which is a so-called two-shaft type. Therefore, the second rotor R2 can rotate independently of the rotation of the first rotor R1. With this structure, the two-shaft gas turbine 1 can operate by rotating the first rotor R1 under optimal conditions, while adjusting the rotation speed of the second rotor R2 according to the load. In other words, the first rotor R1 and the second rotor R2 can rotate at different rotation speeds.

[0021] The bearing device 7 also rotatably supports the intermediate shaft 6. The bearing device 7 is arranged alongside the sealing device 10, which will be described later, in the axial direction Da. The bearing device 7 has a bearing body 71, a bearing housing 72, and a bearing seal 73. The bearing body 71 is a journal bearing. The bearing body 71 is arranged in the internal space of the bearing housing 72. A ventilation pipe 74 that communicates with the outside of the compressor casing 22 is connected to the bearing housing 72. The bearing seal 73 airtightly seals the gap between the bearing housing 72 and the intermediate shaft 6. The bearing seal 73 is, for example, a labyrinth seal having a plurality of fins.

[0022] An inner casing 8, which forms a flow path for compressed air from the compressor 2, is disposed between the compressor rotor 21 and the high-pressure turbine rotor 41. The inner casing 8 is disposed on the outer side Dro in the radial direction Dr with respect to the intermediate shaft 6. That is, the inner casing 8 is formed so as to cover the outer side Dro of the intermediate shaft 6 and the bearing device 7 in the radial direction Dr. The inner casing 8 is disposed on the inner side Dri in the radial direction Dr with respect to the combustor 3. The inner casing 8 is fixed to the compressor casing 22 via, for example, struts (not shown) or the like. That is, the inner casing 8, together with the compressor casing 22, constitutes a part of a stationary member. A cavity 81 in which the bearing device 7 is disposed is formed between the inner casing 8 and the intermediate shaft 6.

[0023] The cavity 81 communicates with the compressor main flow path F1 at a position downstream of the compressor rotor blade 25 located most downstream. That is, the cavity 81 is connected to the compressor main flow path F1 at a position where the highest-pressure compressed air flows in the compressor 2. The cavity 81 also communicates with the gas path flow path F2 between the turbine stator vane 44 and turbine rotor blade 45 located most upstream. That is, the cavity 81 is connected to the gas path flow path F2 at a position where the highest-pressure combustion gas flows in the high-pressure turbine 4.

[0024] The upstream seal portion 9 provides a seal between the outer peripheral surface of the intermediate shaft 6 and the inner casing 8. The upstream seal portion 9 prevents compressed air from flowing from the compressor main flow path F1 into a cavity 81 in which the bearing device 7 is disposed. The upstream seal portion 9 is fixed to the inner casing 8. The upstream seal portion 9 is, for example, a labyrinth seal having a plurality of fins.

[0025] The sealing device 10 seals between the outer peripheral surface of the intermediate shaft 6 and the inner casing 8. The sealing device 10 suppresses the inflow of combustion gas from the gas path flow path F2 into a cavity 81 in which the bearing device 7 is disposed. The sealing device 10 is fixed to the inner casing 8. The sealing devices 10 are arranged side by side at intervals in the axial direction Da so as to face the bearing device 7. As shown in FIG. 3 , the sealing device 10 of this embodiment includes a seal retaining ring 11, a seal ring 12, and a plurality of seal fins 13.

[0026] The seal retaining ring 11 is capable of retaining the seal ring 12 from the outside Dro in the radial direction Dr. The seal retaining ring 11 has a retaining groove 111 into which a portion of the seal ring 12 is inserted. The retaining groove 111 is formed so as to be recessed from the inner circumferential surface of the seal retaining ring 11 toward the inside Dri in the radial direction Dr. The seal retaining ring 11 is formed in an annular shape centered on the seal axis OS. The seal retaining ring 11 is fixed to the inner casing 8.

[0027] Here, the seal axis OS coincides with the axis of the rotating shaft when the sealing device 10 is disposed around the intermediate shaft 6. That is, in the present embodiment, the seal axis OS coincides with the first axis O1 (and the second axis O2) when the sealing device 10 is disposed around the intermediate shaft 6. That is, the seal axis OS extends coaxially and parallel to the first axis O1 (and the second axis O2). That is, the seal axis OS extends in the axial direction Da. Furthermore, the radial direction Dr with respect to the seal axis OS coincides with the radial direction Dr of the gas turbine 1, and the circumferential direction Dc with respect to the seal axis OS coincides with the circumferential direction Dc of the gas turbine 1.

[0028] The seal ring 12 is formed in an annular shape centered on the seal axis OS. The seal ring 12 has a fin fixing surface 121C that faces the outer circumferential surface of the intermediate shaft 6 in the radial direction Dr. The fin fixing surface 121C is an inner circumferential surface that faces the inner side Dri of the seal ring 12 in the radial direction Dr. The seal ring 12 is fixed to the seal retaining ring 11. The seal ring 12 of this embodiment also has a ring main body 121, a ring protruding wall 122, and a ring through hole 123.

[0029] A plurality of seal fins 13 are fixed to the ring body 121. The ring body 121 is fixed to the seal retaining ring 11. The ring body 121 is formed in an annular shape centered on the seal axis OS. The ring body 121 has a fin fixing portion 121A and a retained portion 121B.

[0030] The fin fixing portion 121A is formed in a cylindrical shape with the seal axis OS as its center. The inner peripheral surface of the fin fixing portion 121A serves as a fin fixing surface 121C to which the plurality of seal fins 13 are fixed.

[0031] The held portion 121B is inserted into the holding groove 111. When inserted into the holding groove 111, the held portion 121B is restricted from moving in the axial direction Da or inward Dri in the radial direction Dr. The held portion 121B protrudes from the outer circumferential surface of the fin fixing portion 121A toward the outer side Dro in the radial direction Dr. The held portion 121B protrudes from the middle of the fin fixing portion 121A in the axial direction Da.

[0032] The ring protruding wall 122 protrudes from the end of the ring main body 121 in the axial direction Da so as to approach the outer circumferential surface of the intermediate shaft 6. The ring protruding wall 122 is formed in a position close to the bearing device 7 relative to the multiple seal fins 13 in the axial direction Da. The ring protruding wall 122 is arranged in a position overlapping with the bearing device 7 in the radial direction Dr. In this embodiment, the ring protruding wall 122 is formed at the end of the ring main body 121 facing the bearing device 7. The ring protruding wall 122 is formed at the end of the fin fixing portion 121A in the axial direction Da, and is arranged in a position facing the bearing seal 73 in the axial direction Da. In other words, the ring protruding wall 122 is arranged in a position close to the bearing seal 73 relative to the multiple seal fins 13 in the axial direction Da and in a position overlapping with the bearing seal 73 in the radial direction Dr.

[0033] The ring protruding wall 122 extends from the ring main body 121 inward in the radial direction Dr so as to approach the outer peripheral surface of the intermediate shaft 6 beyond a position overlapping with the position of the gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the multiple seal fins 13 in the radial direction Dr. The ring protruding wall 122 is formed to be longer than the multiple seal fins 13 in the radial direction Dr. Furthermore, the ring protruding wall 122 is formed to gradually taper toward its tip. The gap between the tip of the ring protruding wall 122 and the outer peripheral surface of the intermediate shaft 6 in the radial direction Dr is approximately the same size as the gap between the multiple seal fins 13 and the outer peripheral surface of the intermediate shaft 6 in the radial direction Dr.

[0034] Furthermore, the ring protruding wall 122 is formed of a material that has higher heat resistance than the material of a portion of the bearing device 7 that faces the ring protruding wall 122 in the axial direction Da. In this embodiment, for example, the bearing seal 73 is formed of aluminum. On the other hand, the ring main body 121 including the ring protruding wall 122 is formed of carbon steel. Furthermore, the ring protruding wall 122 in this embodiment has a shielding surface 122F.

[0035] The shielding surface 122F is a surface of the ring protruding wall 122 that faces the seal fin 13 in the axial direction Da. The shielding surface 122F is formed at a position that overlaps with a gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the multiple seal fins 13 in the radial direction Dr. The shielding surface 122F in this embodiment is formed as a plane that is perpendicular to the seal axis OS. In other words, the shielding surface 122F in this embodiment is a plane that extends in the radial direction Dr (vertical direction).

[0036] The ring through hole 123 penetrates the ring main body 121 in the radial direction Dr. In other words, the ring through hole 123 is a through hole formed in a direction perpendicular to the outer circumferential surface of the intermediate shaft 6 when the seal device 10 is disposed around the intermediate shaft 6. In this embodiment, the ring through hole 123 is formed as a rectangular through hole, but may be formed in any shape. The ring through hole 123 is formed at a position closer to the ring protruding wall 122 than the seal fin 13 in the axial direction Da. The ring through hole 123 is formed so as to be adjacent to the shielding surface 122F in the axial direction Da. The ring through hole 123 is formed with an opening area larger than the gap between the outer circumferential surface of the intermediate shaft 6 and the tip of the ring protruding wall 122 in the radial direction Dr. A plurality of ring through holes 123 are formed in the ring main body 121 at intervals in the circumferential direction Dc of the seal ring 12.

[0037] The multiple seal fins 13 protrude from the fin fixing surface 121C toward the outer peripheral surface of the intermediate shaft 6. The multiple seal fins 13 are arranged spaced apart from one another in the axial direction Da. The multiple seal fins 13 are formed in an annular shape centered on the seal axis OS. The tips of the multiple seal fins 13 face the outer peripheral surface of the intermediate shaft 6 with a small gap between them. The multiple seal fins 13 have different lengths in the radial direction Dr in accordance with the shape of the outer peripheral surface of the intermediate shaft 6 so that the gap between them and the outer peripheral surface of the intermediate shaft 6 is constant.

[0038] (Effects) In the seal device 10 of the present embodiment as described above, the ring protruding wall 122 protrudes from the end of the ring main body 121 to which the multiple seal fins 13 are fixed, so as to approach the outer peripheral surface of the intermediate shaft 6. Furthermore, the ring protruding wall 122 extends from the ring main body 121 toward the inner side Dri in the radial direction Dr so as to exceed the position of the gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the seal fins 13 in the radial direction Dr. Therefore, high-temperature, high-pressure combustion gas that flows in the axial direction Da, exceeds the multiple seal fins 13, and leaks so as to be ejected from the gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the seal fins 13 collides with the ring protruding wall 122. Therefore, the combustion gas leaking from the gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the seal fins 13 can be prevented from directly ejecting in the axial direction Da toward the outside of the seal ring 12. Furthermore, in the present embodiment, a ring through-hole 123 penetrating the ring main body 121 in the radial direction Dr is formed at a position closer to the ring protruding wall 122 than the seal fins 13. Therefore, the combustion gas that collides with the ring protruding wall 122 flows so as to be discharged from the ring through-hole 123 formed in a position close to the ring protruding wall 122 to the outside Dro of the seal ring 12. As a result, the combustion gas leaking from the ring through-hole 123 flows outside the seal ring 12 toward the outside Dro in the radial direction Dr without being ejected toward the bearing device 7. In addition, the flow rate of the combustion gas leaking from between the tip of the ring protruding wall 122 and the outer circumferential surface of the intermediate shaft 6 is reduced by the combustion gas flowing out from the ring through-hole 123. This makes it possible to reduce the pressure of the fluid that is discharged from the inside to the outside of the seal device 10, from the gap between the seal fin 13 and the intermediate shaft 6 in the axial direction Da.

[0039] Furthermore, the ring protruding wall 122 has a shielding surface 122F that is perpendicular to the seal axis OS and that overlaps with the gap between the outer peripheral surface of the intermediate shaft 6 and the tip of the seal fin 13 in the radial direction Dr. Therefore, the combustion gas that leaks, as if ejected from the gap between the outer peripheral surface of the intermediate shaft 6 and the tip of the seal fin 13, collides with the shielding surface 122F within the ring protruding wall 122. By colliding with the shielding surface 122F, the combustion gas is guided in the radial direction Dr, such as vertically upward. Therefore, the combustion gas that leaks from the gap between the outer peripheral surface of the intermediate shaft 6 and the tip of the seal fin 13 can be efficiently guided toward the ring through hole 123.

[0040] Furthermore, in this embodiment, the tip of the ring protruding wall 122 approaches the outer peripheral surface of the intermediate shaft 6 to a position approximately equal to the gap in the radial direction Dr between the multiple seal fins 13 and the outer peripheral surface of the intermediate shaft 6. Therefore, there is a possibility that the tip of the ring protruding wall 122 may come into contact with the outer peripheral surface of the intermediate shaft 6. However, the ring protruding wall 122 is formed so as to gradually become thinner toward the tip. Therefore, even if the tip of the ring protruding wall 122 comes into contact with the outer peripheral surface of the intermediate shaft 6, the contact area between the tip of the ring protruding wall 122 and the outer peripheral surface of the intermediate shaft 6 can be reduced. This makes it possible to reduce the impact and damage that the tip of the ring protruding wall 122 may cause to the outer peripheral surface of the intermediate shaft 6.

[0041] Furthermore, the ring through hole 123 is formed with an opening area larger than the gap in the radial direction Dr between the outer peripheral surface of the intermediate shaft 6 and the tip of the ring protruding wall 122. Therefore, more of the combustion gas that collides with the shielding surface 122F flows toward the ring through hole 123 than into the gap between the tip of the ring protruding wall 122 and the outer peripheral surface of the intermediate shaft 6. This allows the combustion gas that collides with the shielding surface 122F to be efficiently guided toward the ring through hole 123.

[0042] Furthermore, a plurality of ring through holes 123 are formed in the ring body 121, spaced apart in the circumferential direction Dc of the seal ring 12. Therefore, the combustion gas that collides with the shielding surface 122F flows over a wide range in the circumferential direction Dc from the ring through holes 123 so as to be discharged to the outside Dro of the seal ring 12. As a result, a large amount of combustion gas flows out from the ring through holes 123, and the flow rate of combustion gas leaking from between the tip of the ring protruding wall 122 and the outer circumferential surface of the intermediate shaft 6 is further reduced. This makes it possible to reduce the pressure of the fluid discharged from the inside of the seal device 10 to the outside in the axial direction Da over a wide range in the circumferential direction Dc.

[0043] Furthermore, the ring protruding wall 122 is disposed in a position closer to the bearing seal 73 than the multiple seal fins 13 in the axial direction Da, and in a position overlapping with the bearing seal 73 in the radial direction Dr. However, most of the combustion gas leaking from the seal device 10 flows out through the ring through hole 123. Therefore, almost no combustion gas leaks in the axial direction Da toward the bearing seal 73 from the gap between the outer peripheral surface of the intermediate shaft 6 and the tip of the seal fin 13. Therefore, it is possible to prevent the combustion gas leaking from the seal device 10 from spraying toward the bearing seal 73. This makes it possible to prevent the leaked combustion gas from affecting the bearing device 7, including the bearing seal 73.

[0044] Furthermore, the ring protruding wall 122 is formed of a material that is more heat resistant than the material of the bearing seal 73. In this way, even if the bearing device 7, which has a bearing seal 73 that is less heat resistant than the ring protruding wall 122, is disposed close to the ring protruding wall 122 in the axial direction Da, the influence of combustion gas on the bearing device 7, including the bearing seal 73, can be suppressed.

[0045] Furthermore, such a sealing device 10 is disposed on the intermediate shaft 6 of the first rotor R1. Therefore, even if the bearing device 7 and the sealing device 10 are disposed side by side in a position inside the inner casing 8 that is difficult to check, as in a two-shaft gas turbine 1, the influence of leaked combustion gas on the bearing device 7 can be suppressed.

[0046] (Other Embodiments) Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope that does not deviate from the gist of the present disclosure are also included.

[0047] In the above embodiments, an example has been described in which the gas turbine 1 is used as the rotary machine. However, the rotary machine may include at least the sealing device 10, a rotating shaft, a stationary member, and a bearing device 7. For example, the rotary machine may be another rotary machine such as an aircraft jet engine, an industrial gas turbine, a steam turbine, a compressor 2, or a motor. Regardless of the target, the same effects as those described above can be obtained.

[0048] Furthermore, the gas turbine 1, which is a rotary machine, is not limited to a multi-shaft type (two-shaft type in this embodiment) as in this embodiment. The gas turbine 1 equipped with the sealing device 10 may be a single-shaft gas turbine 1 or a gas turbine 1 with three or more shafts.

[0049] Furthermore, in this embodiment, the sealing device 10 is disposed relative to the intermediate shaft 6, but the present invention is not limited to such a structure. The sealing device 10 can be disposed relative to a rotating shaft. Therefore, for example, even when the sealing device 10 is disposed in the gas turbine 1 of this embodiment, the sealing device 10 may be disposed at another location on the first rotor R1 or on the second rotor R2. In other words, the sealing device 10 may seal between the compressor rotor 21, which is a rotating shaft, and the compressor casing 22, which is a stationary member. Furthermore, the sealing device 10 may seal between the high-pressure turbine rotor 41, which is a rotating shaft, and the high-pressure turbine casing 42, which is a stationary member.

[0050] Furthermore, as in this embodiment, the bearing device 7 arranged alongside the sealing device 10 in the axial direction Da is not limited to a structure supporting the intermediate shaft 6. For example, when the sealing device 10 is arranged at another location on the first rotor R1 or relative to the second rotor R2, the bearing device 7 may be structured to support another location on the first rotor R1 or the second rotor R2 at a position arranged relative to the sealing device 10 in the axial direction Da.

[0051] Furthermore, the seal device 10 is not limited to the structure of this embodiment. The seal device 10 may include a seal ring 12 and a plurality of seal fins 13. Therefore, the seal device 10 may not include a seal retaining ring 11, and may have a structure in which the seal ring 12 is directly fixed to a stationary member. Furthermore, the seal device 10 may further include a brush seal between the plurality of seal fins 13 in the axial direction Da.

[0052] <Additional Notes> The sealing device 10 and the rotary machine described in each embodiment can be understood, for example, as follows.

[0053] (1) A seal device 10 according to a first aspect is a seal device 10 that seals between an outer peripheral surface of a rotating shaft and a stationary member arranged on the outer side Dro of the rotating shaft in a radial direction Dr, and includes a seal ring 12 that is formed in an annular shape around a seal axis OS and has a fin fixing surface 121C that faces the outer peripheral surface of the rotating shaft in the radial direction Dr, and a plurality of seal fins 13 that are formed in an annular shape around the seal axis OS and protrude from the fin fixing surface 121C toward the outer peripheral surface of the rotating shaft, and the seal ring 12 includes a ring body 121 to which the plurality of seal fins 13 are fixed, and a seal ring 12 that is formed in an annular shape around the seal axis OS and protrudes from the fin fixing surface 121C toward the outer peripheral surface of the rotating shaft. The ring body 121 has a ring protruding wall 122 that protrudes from an end of the ring body 121 in the axial direction Da in which the rotor axis OS extends, so as to approach the outer peripheral surface of the rotating shaft, and a ring through hole 123 that is formed in the axial direction Da at a position closer to the ring protruding wall 122 than the seal fins 13 and penetrates the ring body 121 in the radial direction Dr, and the ring protruding wall 122 extends from the ring body 121 to the inner side Dri in the radial direction Dr so as to approach the outer peripheral surface of the rotating shaft beyond a position that overlaps with the position of the gap between the outer peripheral surface of the rotating shaft and the tips of the plurality of seal fins 13 in the radial direction Dr.

[0054] According to this configuration, the ring protruding wall 122 protrudes from the end of the ring main body 121 to which the multiple seal fins 13 are fixed, so as to approach the outer peripheral surface of the rotating shaft. Furthermore, the ring protruding wall 122 extends from the ring main body 121 toward the inner side Dri in the radial direction Dr so as to exceed the position of the gap between the outer peripheral surface of the rotating shaft and the tips of the seal fins 13 in the radial direction Dr. Therefore, fluid that flows in the axial direction Da, exceeds the multiple seal fins 13, and leaks out of the gap between the outer peripheral surface of the intermediate shaft 6 and the tips of the seal fins 13 collides with the ring protruding wall 122. This prevents fluid leaking out of the gap between the outer peripheral surface of the rotating shaft and the tips of the seal fins 13 from directly spraying out of the seal ring 12 in the axial direction Da. Furthermore, a ring through-hole 123 is formed in a position closer to the ring protruding wall 122 than the seal fins 13, penetrating the ring main body 121 in the radial direction Dr. Therefore, the fluid that collides with the ring protruding wall 122 flows to be discharged to the outside Dro of the seal ring 12 through the ring through-hole 123 formed in a position close to the ring protruding wall 122. In addition, the flow rate of the fluid leaking from between the tip of the ring protruding wall 122 and the outer circumferential surface of the rotating shaft is reduced by the fluid flowing out from the ring through-hole 123. This makes it possible to reduce the pressure of the fluid discharged in the axial direction Da from the gap between the seal fin 13 and the rotating shaft.

[0055] (2) The sealing device 10 according to the second aspect is the sealing device 10 of (1), wherein the ring protruding wall 122 is formed at a position that overlaps with the gap between the outer peripheral surface of the rotating shaft and the tips of the plurality of sealing fins 13 in the radial direction Dr, and has a shielding surface 122F that is perpendicular to the seal axis OS.

[0056] With this configuration, the fluid leaking from the gap between the outer circumferential surface of the rotating shaft and the tip of the seal fin 13 collides with the shielding surface 122F within the ring protruding wall 122. By colliding with the shielding surface 122F, the fluid is guided in the radial direction Dr. Therefore, the combustion fluid leaking from the gap between the outer circumferential surface of the rotating shaft and the tip of the seal fin 13 can be efficiently guided toward the ring through hole 123.

[0057] (3) The seal device 10 according to a third aspect is the seal device 10 of (1) or (2), in which the ring protruding wall 122 is formed so as to gradually taper toward the tip.

[0058] With this configuration, even if the tip of the ring protruding wall 122 comes into contact with the outer circumferential surface of the rotating shaft, the contact area between the tip of the ring protruding wall 122 and the outer circumferential surface of the rotating shaft can be reduced, thereby reducing the impact and damage that the tip of the ring protruding wall 122 may cause to the outer circumferential surface of the rotating shaft.

[0059] (4) The sealing device 10 according to the fourth aspect is any one of the sealing devices 10 of (1) to (3), in which the ring through hole 123 is formed with an opening area larger than the gap between the outer peripheral surface of the rotating shaft in the radial direction Dr and the tip of the ring protruding wall 122.

[0060] With this configuration, the fluid that collides with the ring protruding wall 122 flows more toward the ring through hole 123 than into the gap between the tip of the ring protruding wall 122 and the outer circumferential surface of the rotating shaft. This allows the fluid that collides with the ring protruding wall 122 to be efficiently guided toward the ring through hole 123.

[0061] (5) The sealing device 10 according to the fifth aspect is any one of the sealing devices 10 of (1) to (4), and the ring through holes 123 are formed in the ring body 121 at intervals in the circumferential direction Dc of the sealing ring 12.

[0062] With this configuration, the fluid that collides with the ring protruding wall 122 flows over a wide range in the circumferential direction Dc so as to be discharged from the ring through hole 123 to the outside Dro of the seal ring 12. As a result, a large amount of fluid flows out from the ring through hole 123, and the flow rate of the fluid leaking out from between the tip of the ring protruding wall 122 and the outer circumferential surface of the rotating shaft is further reduced. This makes it possible to reduce the pressure of the fluid that is discharged from the inside to the outside of the seal device 10 in the axial direction Da over a wide range in the circumferential direction Dc.

[0063] (6) A rotary machine according to a sixth aspect includes a sealing device 10 of any one of (1) to (5), a rotating shaft whose outer peripheral surface is sealed by the sealing device 10, a stationary member to which the seal ring 12 is fixed and which covers the rotating shaft, and a bearing device 7 arranged alongside the sealing device 10 in the axial direction Da and which rotatably supports the rotating shaft, wherein the ring protruding wall 122 is positioned close to the bearing device 7 relative to the plurality of sealing fins 13 in the axial direction Da and is positioned so as to overlap with the bearing device 7 in the radial direction Dr.

[0064] With this configuration, most of the fluid leaking from the seal device 10 flows out through the ring through-hole 123. Therefore, almost no fluid leaks in the axial direction Da from the gap between the outer circumferential surface of the rotating shaft and the tip of the seal fin 13 toward the bearing device 7. Therefore, it is possible to prevent the fluid leaking from the seal device 10 from spraying toward the bearing seal 73. This makes it possible to prevent the leaked fluid from affecting the bearing device 7.

[0065] (7) The rotating machine according to the seventh aspect is the rotating machine of (6), in which the ring protruding wall 122 is formed of a material that is more heat resistant than the material of the position opposite the ring protruding wall 122 in the axial direction Da in the bearing device 7.

[0066] With this configuration, even if the bearing device 7, which has lower heat resistance than the ring protruding wall 122, is positioned close to the ring protruding wall 122 in the axial direction Da, the influence of the fluid on the bearing device 7 can be suppressed.

[0067] (8) A rotary machine according to an eighth aspect is the rotary machine of (6) or (7), and includes: a compressor 2 that compresses air and discharges the compressed air; a turbine having a high-pressure turbine 4 and a low-pressure turbine 5 that are coaxially connected to the compressor 2 and that can rotate independently of the high-pressure turbine 4; and a combustor 3 that generates combustion gas using the compressed air generated by the compressor 2 and fuel and supplies the combustion gas to the high-pressure turbine 4, wherein the compressor 2 has a compressor rotor 21 that rotates about a first axis O1, and the high-pressure turbine The bin 4 has a high-pressure turbine rotor 41 that rotates about the first axis O1, the low-pressure turbine 5 has a low-pressure turbine rotor 51 that rotates about the first axis O1, the compressor rotor 21 and the high-pressure turbine rotor 41 form a first rotor R1 that is the rotating shaft, and the low-pressure turbine rotor 51 forms a second rotor R2 that is arranged away from the first rotor R1 in the axial direction Da and can rotate independently of the first rotor R1, thereby forming a two-shaft gas turbine 1.

[0068] With this configuration, even if the bearing device 7 and the sealing device 10 are arranged side by side in a location that is difficult to check, such as in a two-shaft gas turbine 1, it is possible to prevent leaked combustion gas from affecting the bearing device 7.

[0069] According to the seal device and rotary machine of the present disclosure, it is possible to reduce the pressure of the fluid that is discharged in the axial direction from the gap between the fin and the rotary shaft.

[0070] REFERENCE SIGNS LIST 1 Gas turbine 2 Compressor 21 Compressor rotor 22 Compressor casing O1 First axis 25 Compressor rotor blade F1 Compressor main flow path 3 Combustor 4 High-pressure turbine 41 High-pressure turbine rotor 42 High-pressure turbine casing 44 Turbine stator vane 45 Turbine rotor blade F2 Gas path flow path 6 Intermediate shaft R1 First rotor 5 Low-pressure turbine O2 Second axis 51 Low-pressure turbine rotor 52 Low-pressure turbine casing R2 Second rotor 7 Bearing device 71 Bearing body 72 Bearing box 73 Bearing seal 74 Ventilation pipe 8 Inner casing 81 Cavity 9 Upstream seal portion 10 Seal device OS Seal axis 11 Seal retaining ring 111 Retaining groove 12 Seal ring 121 Ring body 121A Fin fixing portion 121B Retained part 121C Fin fixing surface 122 Ring protruding wall 122F Shielding surface 123 Ring through hole 13 Seal fin Da Axial direction D1 First side D2 Second side Dr Radial direction Dri Inside Dro Outside Dc Circumferential direction

Claims

1. A seal device that seals between an outer peripheral surface of a rotating shaft and a stationary member arranged radially outward from the rotating shaft, comprising: a seal ring formed in an annular shape centered on a seal axis and having a fin fixing surface that faces the outer peripheral surface of the rotating shaft in the radial direction; and a plurality of seal fins formed in an annular shape centered on the seal axis and protruding from the fin fixing surface toward the outer peripheral surface of the rotating shaft, wherein the seal ring has: a ring body to which the plurality of seal fins are fixed; a ring protruding wall that protrudes from an end of the ring body in the axial direction along which the seal axis extends so as to approach the outer peripheral surface of the rotating shaft; and a ring through hole that is formed in the axial direction at a position closer to the ring protruding wall than the seal fins and that passes radially through the ring body, wherein the ring protruding wall extends radially inward from the ring body so as to approach the outer peripheral surface of the rotating shaft beyond a position that overlaps with the position of the gap between the outer peripheral surface of the rotating shaft and the tips of the plurality of seal fins.

2. A seal device as described in claim 1, wherein the ring protruding wall is formed at a position that overlaps with the gap between the outer peripheral surface of the rotating shaft and the tips of the plurality of seal fins in the radial direction, and has a shielding surface that is perpendicular to the seal axis.

3. A seal device according to claim 1 or 2, wherein the ring protruding wall is formed so as to gradually taper towards its tip.

4. A sealing device according to claim 1 or 2, wherein the ring through-hole is formed with an opening area larger than the gap between the outer peripheral surface of the rotary shaft and the tip of the ring protruding wall in the radial direction.

5. A seal device according to claim 1 or 2, wherein a plurality of the ring through holes are formed in the ring body at intervals in the circumferential direction of the seal ring.

6. A rotary machine comprising: a sealing device as defined in claim 1 or 2; a rotating shaft whose outer peripheral surface is sealed by the sealing device; a stationary member to which the seal ring is fixed and which covers the rotating shaft; and a bearing device which is arranged alongside the sealing device in the axial direction and rotatably supports the rotating shaft, wherein the ring protruding wall is positioned in a position close to the bearing device relative to the plurality of seal fins in the axial direction and overlaps with the bearing device in the radial direction.

7. A rotary machine according to claim 6, wherein the ring protruding wall is formed of a material having a higher heat resistance than a material of a portion of the bearing device that faces the ring protruding wall in the axial direction.

8. The rotary machine according to claim 7, which is a two-shaft gas turbine comprising: a compressor that compresses air and discharges the compressed air; a turbine having a high-pressure turbine connected coaxially to the compressor and a low-pressure turbine that can rotate independently of the high-pressure turbine; and a combustor that generates combustion gas from the compressed air generated by the compressor and fuel and supplies the combustion gas to the high-pressure turbine, wherein the compressor has a compressor rotor that rotates about a first axis, the high-pressure turbine has a high-pressure turbine rotor that rotates about the first axis, and the low-pressure turbine has a low-pressure turbine rotor that rotates about the first axis, the compressor rotor and the high-pressure turbine rotor constitute a first rotor that is the rotating shaft, and the low-pressure turbine rotor is arranged axially spaced apart from the first rotor and constitutes a second rotor that can rotate independently of the first rotor.

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