Seal structure

The present application claims priority based on Japanese Patent Application No. 2014-196771 filed on Sep. 26, 2014, the contents of which are incorporated herein by reference.

The present invention relates to a seal structure.

In a gas turbine, air pressurized in a compressor is mixed with fuel in a combustor to generate combustion gas that is a high-temperature fluid, and this combustion gas is introduced into a combustion gas flow passage of a turbine in which vanes and blades are alternately installed. The gas turbine rotates the blades and a rotor by the combustion gas flowing through the combustion gas flow passage. Thus, the gas turbine outputs the energy of the combustion gas as rotary energy, and imparts a rotary driving force to the compressor and a generator.

A clearance is provided between a transition piece of the combustor and a shroud of a first-stage vane of the turbine to prevent contact therebetween to thermal expansion. In this clearance, a seal member is provided to prevent casing air from leaking into the combustion gas flow passage (e.g., Japanese Patent Publication No. 2009-167905).

The surfaces of components of the gas turbine exposed to the combustion gas have a thermal barrier coating (TBC) applied thereto as a heat-resistant coating to enhance the heat resistance. This thermal barrier coating is applied to those regions that reach high temperatures by being exposed to the combustion gas. The thermal barrier coating is applied not only to a gas path surface facing the combustion gas flow passage, but also to a lateral wall surface intersecting with the gas path surface, on the side of the surface closer to the combustion gas flow passage.

Technical Problem

In such a gas turbine, the temperatures of members composing the gas turbine, such as the transition pieces, blades, vanes, and casings, are higher when the gas turbine is in a steady operation state than when the gas turbine is in a stopped state. In the course of the gas turbine temperature rising at startup, differences in temperature among the members composing the gas turbine result in differences in thermal elongation. Accordingly, clearances between the members vary with the operation state of the gas turbine, from the stopped state to the steady operation state of the gas turbine. Thus, if a clearance between adjacent members is reduced due to the difference in thermal elongation, the lateral wall surfaces facing each other may come in contact with each other, causing damage to the heat-resistant coating due to the occurrence of a phenomenon such as detachment of the thermal barrier coating.

The present invention provides a seal structure that can prevent damage to the heat-resistant coatings of adjacent members even if these members come in contact with each other.

Solution to Problem

A seal structure in a first aspect of the present invention includes: a first member disposed so as to face a combustion gas flow passage formed around a rotor axis; a second member disposed adjacent to the first member so as to face the combustion gas flow passage; a third member disposed on the outer side of the combustion gas flow passage between a first end face of the first member and a second end face of the second member facing the first end face, and engaging with the first member and the second member; a heat-resistant coating formed on at least one of the first end face and the second end face, on the side of the face closer to the combustion gas flow passage; and a contact part disposed in the first end face and the second end face, further on the outer side of the combustion gas flow passage than the heat-resistant coating, and, when the first member and the second member move relatively toward each other, restricting the relative movement by directly coming in contact with the first member and the second member, or indirectly coming in contact with the first member and the second member through the third member, in a state where a clearance is left between the heat-resistant coating and at least one of the first end face and the second end face facing the heat-resistant coating.

According to this configuration, before the first end face and the second end face come in contact with each other, the contact part comes in contact with the first end face and the second end face, or with at least one face, on which the heat-resistant coating is not formed, through the third member. It is therefore possible to restrict the relative movement of the first member and the second member so that the first end face and the second end face do not approach each other beyond a position at which the contact part directly comes in contact with the first end face and the second end face, or indirectly comes in contact with the first end face and the second end face through the third member. Thus, contact between the first end face of the first member on which the heat-resistant coating is formed and the second end face of the second member, adjacent to the first member, on which the heat-resistant coating is formed can be prevented.

A seal structure in a second aspect of the present invention is the seal structure according to the first aspect, wherein the first member may be a combustor; the second member may be a vane disposed on the downstream side in a rotor axis direction relative to the combustor; and the third member may be a seal member disposed on the outer side of the combustion gas flow passage.

According to this configuration, the first member is a combustor, the second member is a vane adjacent to the downstream side of the combustor in the rotor axis direction, and the third member is a seal member disposed between the combustor and the vane. Thus, the seal structure that can protect the heat-resistant coating in the vicinity of the outlet of the combustor can be easily employed.

A seal structure in a third aspect of the present invention is the seal structure according to the second aspect, wherein the seal member may include: cooling channels formed in a certain region extending in a circumferential direction based on the rotor axis, at positions including a position on the upstream side in the rotor axis direction relative to a leading edge of the vane facing the upstream side in the rotor axis direction; and a third end face having a plurality of openings which are provided in the circumferential direction and from which cooling air flowing through the cooling channels is discharged.

According to this configuration, it is possible to effectively cool the seal member in the vicinity of the leading edge that tends to reach a high temperature as the combustion gas flowing into the combustion gas flow passage impinges on the leading edge and is thereby entrapped. Specifically, as the combustion gas impinges on the leading edge, the part of the seal member on the upstream side of the leading edge in the rotor axis direction reaches a higher temperature than the other part in the circumferential direction. It is therefore possible to efficiently supply cooling air to that part that reaches a higher temperature and cool the seal member by providing the cooling channels having the openings in the seal member located on the upstream side of the leading edge in the rotor axis direction. As a result, the flow rate of cooling air passed through the cooling channels to cool the seal member can be reduced.

A seal structure in a fourth aspect of the present invention is the seal structure according to the third aspect, wherein the seal member may include a clearance forming portion that protrudes from the third end face toward the downstream side in the rotor axis direction and has a fourth end face facing the downstream side in the rotor axis direction.

According to this configuration, the clearance forming portion protrudes further toward the downstream side in the rotor axis direction than the third end face. Thus, the openings from which the cooling air is discharged are not blocked, so that the seal member is stably cooled.

A seal structure in a fifth aspect of the present invention is the seal structure according to the fourth aspect, wherein the fourth end face may be disposed so as to face the contact part of the second end face of the vane facing the upstream side in the rotor axis direction.

According to this configuration, even if the clearance between the third end face in which the openings are disposed and the lateral end face of the vane facing the third end face from the downstream side in the rotor axis direction is reduced, the contact part of the lateral end face comes in contact with the fourth end face before the openings are blocked. Thus, a space in front of the openings can be stably secured, so that the required cooling air can be continuously discharged from the openings even if the clearance between the end face and the lateral end face is reduced.

A seal structure in a sixth aspect of the present invention is the seal structure according to the first aspect, wherein the first member and the second member may be ring segments adjacent to each other in a circumferential direction based on the rotor axis, and the third member may be a seal plate disposed between the adjacent ring segments.

According to this configuration, the first member and the second member are ring segments adjacent to each other in the circumferential direction, and the third member is a seal plate disposed between the adjacent ring segments. Thus, the seal structure that can protect the heat-resistant coating can be easily employed between a pair of ring segments adjacent to each other in the circumferential direction.

Advantageous Effects of Invention

According to the seal structure of the present invention, it is possible to prevent contact between the surfaces of adjacent members facing each other at a contact part and thus prevent damage to the heat-resistant coatings.

FIG. 1 is a cutaway side view of main parts of a gas turbine in an embodiment of the present invention.

FIG. 2 is a sectional view of main parts of the gas turbine in the embodiment of the present invention.

FIG. 3 is an enlarged view of main parts illustrating a seal structure in a first embodiment of the present invention.

FIG. 4 is an enlarged view of main parts illustrating a seal member as seen from the downstream side in an axial direction in the first embodiment of the present invention.

FIG. 5 is a schematic view illustrating the positions of openings of the seal member in the first embodiment of the present invention.

FIG. 6 is a sectional view illustrating the section VI-VI in FIG. 4 .

FIG. 7 is an enlarged view of main parts illustrating a ring segment in a second embodiment of the present invention.

FIG. 8 is a sectional view of main parts illustrating a seal structure in the second embodiment of the present invention.

First Embodiment

A first embodiment according to the present invention will be described below with reference to FIG. 1 to FIG. 6 .

As shown in FIG. 1 and FIG. 2 , a gas turbine 1 includes a compressor 10 that generates compressed air A by compressing outside air, a plurality of combustors 20 that generate combustion gas G by mixing fuel to the compressed air A and combusting the mixture, and a turbine 30 driven by the combustion gas G.

The turbine 30 includes a casing 31 , and a turbine rotor 33 that rotates around a rotor axis Ar inside the casing 31 . For example, the turbine rotor 33 is connected to a generator (not shown) that generates electricity as the turbine rotor 33 rotates.

Relative to the turbine 30 , the compressor 10 is disposed on one side of the rotor axis Ar. The casing 31 of the turbine 30 has a cylindrical shape around the rotor axis Ar. Part of the compressed air A is supplied as cooling air from the compressor 10 to the turbine 30 and the combustors 20 .

The plurality of combustors 20 are mounted on the casing 31 at intervals in a circumferential direction Dc relative to the rotor axis Ar.

Here, the direction in which the rotor axis Ar extends will be referred to as a rotor axis direction Da. In the rotor axis direction Da, the side on which the turbine 30 is disposed relative to the combustors 20 will be referred to as the downstream side, and the opposite side will be referred to as the upstream side.

A circumferential direction Dc based on the rotor axis Ar will be referred to simply as the circumferential direction Dc, and a radial direction Dr based on the rotor axis Ar will be referred to simply as the radial direction Dr.

In the radial direction Dr, the side away from an axis line Ac will be referred to as the outer side in the radial direction Dr, and the opposite side will be referred to as the inner side in the radial direction Dr.

As shown in FIG. 2 , the turbine rotor 33 has a rotor main body 34 extending in the rotor axis direction Da around the rotor axis Ar, and a plurality of blade rows 35 arrayed in the rotor axis direction Da and mounted on the rotor main body 34 . The blade rows 35 each have a plurality of blades 36 that are arrayed in the circumferential direction Dc relative to the rotor axis Ar and mounted around the rotor axis Ar. The blade 36 has a blade main body 37 extending in the radial direction Dr, a platform 38 provided on the inner side of the blade main body 37 in the radial direction Dr, and a blade root 39 provided on the inner side of the platform 38 in the radial direction Dr. The blade 36 is fixed to the rotor main body 34 as the blade root 39 is embedded into the rotor main body 34 .

Vane rows 40 are disposed respectively on the upstream side of the plurality of blade rows 35 . The vane rows 40 are each composed of a plurality of vanes 41 arrayed in the circumferential direction Dc. Each vane 41 has a vane main body 42 extending toward the outer side in the radial direction Dr, an outer shroud 43 provided on the outer side of the vane main body 42 in the radial direction Dr, and an inner shroud 45 provided on the inner side of the vane main body 42 in the radial direction Dr.

A blade ring 50 having a cylindrical shape around the rotor axis Ar is disposed on the outer side of the blade row 35 and the vane row 40 in the radial direction Dr, on the inner side of the casing 31 in the radial direction Dr. The blade ring 50 is fixed to the casing 31 . The outer shroud 43 of the vane 41 and the blade ring 50 are coupled together by a heat shield ring 52 .

A plurality of ring segments 60 arrayed in the circumferential direction Dc around the rotor axis Ar are disposed between the outer shrouds 43 of the vane rows 40 adjacent to each other in the rotor axis direction Da. The plurality of ring segments 60 arrayed in the circumferential direction Dc form an annular shape. The blade row 35 is disposed on the inner side of the ring segments 60 in the radial direction Dr. All the plurality of ring segments 60 arrayed in the circumferential direction Dc are coupled to the blade ring 50 by the heat shield ring 52 .

A combustion gas flow passage Pg through which the combustion gas G flows is formed inside a transition piece 21 of the combustor 20 , to be described later, and inside the casing 31 of the turbine 30 . The combustion gas flow passage Pg inside the casing 31 of the turbine 30 is defined annularly around the rotor main body 34 by the inner shrouds 45 and the outer shrouds 43 of the plurality of vanes 41 composing the vane row 40 , the platforms 38 of the plurality of blades 36 composing the blade row 35 on the downstream side of the vane row 40 , and the ring segments 60 facing the platforms 38 .

The combustor 20 includes the transition piece 21 that sends the high-temperature high-pressure combustion gas G to the turbine 30 , and a fuel supply unit 22 that supplies the fuel and the compressed air A into the transition piece 21 .

A flame is formed inside the fuel supply unit 22 . The fuel supply unit 22 has a combustor basket 22 a having a tubular shape around the axis line Ac.

The transition piece 21 is connected to the combustor basket 22 a . The transition piece 21 supplies the high-temperature high-pressure combustion gas G generated in the combustor basket 22 a to the turbine 30 . The transition piece 21 has a tubular shape. Specifically, an outlet opening of the transition piece 21 located on the downstream side in the rotor axis direction Da has a roughly quadrangular shape. Accordingly, the combustion gas flow passage Pg inside the transition piece 21 is defined by an inner circumferential surface 21 a of the tubular transition piece 21 . The transition piece 21 of this embodiment is a first member in a seal structure 100 of the first embodiment. The transition piece 21 of this embodiment has an outlet flange 210 ( FIG. 3 ) that is located on the downstream side in the rotor axis direction Da and protrudes in the radial direction Dr from an outer circumferential surface of the transition piece 21 .

The seal structure 100 prevents the compressed air A inside the casing 31 from leaking toward the combustion gas flow passage Pg while preventing contact between the surfaces of adjacent members facing each other. The seal structure 100 of the first embodiment is disposed between the combustor 20 and the vane row 40 of the turbine 30 adjacent to the downstream side of the combustor 20 in the rotor axis direction Da. Specifically, the seal structure 100 of the first embodiment seals the clearance between the transition piece 21 and a first vane row 40 a that are adjacent to each other in the rotor axis direction Da, without allowing contact between heat-resistant coatings 130 formed on the transition piece 21 and the first vane row 40 a.

The seal structure 100 shown in FIG. 3 that is located on the inner side in the radial direction Dr relative to the combustion gas flow passage Pg is a structure including the transition piece 21 , the inner shrouds 45 of the first vane row 40 a , and a seal member 7 (inner seal member 7 a ). The transition piece 21 is disposed on the upstream side in the rotor axis direction Da. The inner shrouds 45 are disposed on the downstream side in the rotor axis direction Da. The seal member 7 (inner seal member 7 a ) is disposed on the inner side in the radial direction Dr relative to the combustion gas flow passage Pg, between the transition piece 21 and the inner shrouds 45 . On the other hand, the seal structure 100 located on the outer side in the radial direction Dr relative to the combustion gas flow passage Pg is a structure including the transition piece 21 , the outer shrouds 43 of the first vane row 40 a , and the seal member 7 (outer seal member 7 b ). The outer shrouds 43 are disposed on the downstream side in the rotor axis direction Da. The seal member 7 (outer seal member 7 b ) is disposed on the outer side in the radial direction Dr relative to the combustion gas flow passage Pg, between the transition piece 21 and the outer shrouds 43 . Both structures are symmetrical with respect to the axis line Ac of the combustor. Both structures are combined and integrated to form the seal structure. The components of the seal structure 100 include the heat-resistant coating 130 and a contact part 140 . The heat-resistant coating 130 is formed on the surfaces of the transition piece 21 and the first vane row 40 a that are exposed to the combustion gas G. The contact part 140 restricts the relative movement of the transition piece 21 and the first vane row 40 a toward each other.

The outlet flange 210 has a substantially quadrangular annular shape so as to cover the periphery of the outlet opening of the transition piece 21 . The outlet flange 210 protrudes from the outer circumferential surface of the transition piece 21 toward the outer side of the combustion gas flow passage Pg. Specifically, the outlet flange 210 has a pair of circumferential flange portions 210 a and a pair of radial flange portions (not shown).

The pair of circumferential flange portions 210 a each protrude from a part of the outer circumferential surface of the transition piece 21 that extends in the circumferential direction Dc. The pair of circumferential flange portions 210 a are disposed so as to face each other in the radial direction Dr across the outlet opening.

As shown in FIG. 3 , a rear end 211 of the transition piece 21 located on the downstream side in the rotor axis direction Da extends further toward the downstream side in the rotor axis direction Da than the outlet flange 210 .

Here, the surface of the transition piece 21 of the first embodiment facing the downstream side in the rotor axis direction Da will be referred to as a first end face 101 . Specifically, the first end face 101 of the first embodiment is formed by a main body first end face 111 that is the face of the rear end 211 facing the downstream side in the rotor axis direction Da, and a flange first end face 121 that is the face of the outlet flange 210 facing the downstream side in the rotor axis direction Da.

Of the vane rows 40 , the first vane row 40 a is disposed on the most upstream side in the rotor axis direction Da. The first vane row 40 a is composed of a plurality of first vanes 41 a adjacent to one another in the circumferential direction Dc. The first vane row 40 a is supported by the blade ring 50 . The gap between the first vane row 40 a and the transition piece 21 of the combustor 20 is sealed by the seal member 7 . The first vane 41 a of this embodiment is a second member in the seal structure 100 of the first embodiment. The first vane 41 a is adjacent to the downstream side in the rotor axis direction Da of the transition piece 21 that is the first member.

As shown in FIG. 3 , a shroud main body 44 having a gas path surface 441 facing the combustion gas flow passage Pg and a lateral wall 46 intersecting with the gas path surface 441 are formed in the inner shroud 45 and the outer shroud 43 of the first vane 41 a . The lateral wall 46 has a lateral end face 461 facing the upstream side in the rotor axis direction Da. The lateral end face 461 is disposed so as to face the main body first end face 111 of the rear end 211 of the transition piece 21 and the flange first end face 121 of the outlet flange 210 , with a clearance left in the rotor axis direction Da between the lateral end face 461 and the end faces. A projection 424 extending from the lateral end face 461 toward the upstream side in the rotor axis direction Da is formed on the lateral wall 46 .

The projection 424 is formed at a position away from the gas path surface 441 of the lateral end face 461 , on the inner side in the radial direction Dr or the outer side in the radial direction Dr of the gas path surface 441 . The projection 424 has an annular shape around the rotor axis Ar. A projection second end face 112 of the projection 424 that faces the upstream side in the rotor axis direction Da is disposed so as to face the flange first end face 121 of the outlet flange 210 , with a clearance left therebetween in the rotor axis direction Da.

Here, the face of the first vane 41 a of the first embodiment that faces the upstream side in the rotor axis direction Da will be referred to as a second end face 102 . Specifically, the second end face 102 of the first embodiment is formed by the lateral end face 461 and the projection second end face 112 of the inner shroud 45 and the outer shroud 43 .

The seal member 7 is a transition piece seal that is disposed between the combustor 20 and the first vane row 40 a that is disposed on the downstream side of the combustor 20 in the rotor axis direction Da and faces the combustion gas flow passage Pg. The seal member 7 seals the gap between the outlet flange 210 of the transition piece 21 of the combustor 20 and the inner shrouds 45 and the outer shrouds 43 of the first vanes 41 a of the first vane row 40 a . The seal member 7 of this embodiment is a third member in the seal structure 100 of the first embodiment.

The seal member 7 engages with the transition piece 21 and the inner shrouds 45 or the outer shrouds 43 of the first vanes 41 a between the main body first end face 111 and the flange first end face 121 constituting the first end face 101 and the lateral end face 461 and the projection second end face 112 constituting the second end face 102 .

The seal member 7 of this embodiment is disposed along the circumferential flange portion 210 a of the substantially quadrangular annular outlet flange 210 . The seal member 7 (inner seal member 7 a ) engages with the circumferential flange portion 210 a on the inner side in the radial direction Dr and with the inner shrouds 45 of the first vanes 41 a . The seal member 7 (outer seal member 7 b ) engages with the circumferential flange portion 210 a on the outer side in the radial direction Dr and with the outer shrouds 43 of the first vanes 41 a.

The shapes of the seal member 7 on the inner side in the radial direction Dr (inner seal member 7 a ) and the seal member 7 on the outer side in the radial direction Dr (outer seal member 7 b ) are roughly symmetrical with respect to the axis line Ac of the transition piece 21 . In the following description, therefore, the seal structure 100 including the inner seal member 7 a engaging with the inner shroud 45 on the inner side in the radial direction Dr will be mainly described as a typical example, but the same description is applicable to the outer seal member 7 b as well. In the following description, “seal member 7 ” will be used as the name and the reference sign of the inner seal member 7 a.

The seal member 7 is disposed on the outer side of the combustion gas flow passage Pg through which the combustion gas G flows (on the inner side in the radial direction Dr). As shown in FIG. 3 , the seal member 7 is disposed in a cavity C that is formed in the clearance between the transition piece 21 and the inner shroud 45 of the first vane 41 a . Here, the cavity C in this embodiment is the space formed between the transition piece 21 and the first vane 41 a and facing the combustion gas flow passage Pg. Relative to the combustion gas flow passage Pg, the cavity C is formed further on the inner side in the radial direction Dr than the inner circumferential surface 21 a of the transition piece 21 and the gas path surface 441 of the first vane 41 a . The cavity C is the space located further on the inner side in the radial direction Dr than the rear end 211 of the transition piece 21 and defined between the outlet flange 210 and the lateral end face 461 in the rotor axis direction Da.

The seal member 7 is a member that is formed annularly in the circumferential direction Dc, with a constant shape in cross-section including the axis line Ac and spreading in the radial direction Dr. The seal member 7 of this embodiment has a main body part 70 , a first protrusion 71 , a second protrusion 72 , a third protrusion 73 , and a fourth protrusion 74 . In the cross-section including the axis line Ac and spreading in the radial direction Dr, the main body part 70 extends in the radial direction Dr. In the cross-section including the axis Ac and spreading in the radial direction Dr, the first protrusion 71 protrudes from an end of the main body part 70 toward the downstream side in the rotor axis direction Da. In the cross-section including the axis line Ac and spreading in the radial direction Dr, the second protrusion 72 is located further on the inner side in the radial direction Dr than the first protrusion 71 and extends from the main body part 70 toward the downstream side in the rotor axis direction Da. In the cross-section including the axis line Ac and spreading in the radial direction Dr, the third protrusion 73 protrudes from the end of the main body part 70 located on the inner side in the radial direction Dr toward the upstream side in the rotor axis direction Da. In the cross-section including the axis line Ac and spreading in the radial direction Dr, the fourth protrusion 74 protrudes from the end of the third protrusion 73 located on the upstream side in the rotor axis direction Da toward the outer side in the radial direction Dr. The seal member 7 of this embodiment has cooling channels 80 through which cooling air is discharged from openings 80 a.

The main body part 70 of this embodiment has a substantially rectangular shape of which the cross-section including the axis line Ac and spreading in the radial direction Dr is long in the radial direction Dr.

The first protrusion 71 protrudes from the end of the main body part 70 toward the lateral end face 461 . The first protrusion 71 of this embodiment has a substantially rectangular parallelepiped shape of which the cross-section including the axis line Ac and spreading in the radial direction Dr is long in the rotor axis direction Da. The first protrusion 71 has an annular shape around the rotor axis Ar. The first protrusion 71 is formed in the space defined in the rotor axis direction Da between the first end face 101 of the rear end 211 of the transition piece 21 and the projection 424 . The first protrusion 71 has an end face 71 a that is a third end face facing the lateral end face 461 and facing the downstream side in the rotor axis direction Da. In the first protrusion 71 , the cooling channels 80 are formed in the rotor axis direction Da. The ends of the cooling channels 80 on the downstream side are connected to the openings 80 a having circular shapes in the end face 71 a.

The end face 71 a of this embodiment is the face at the end of the first protrusion 71 that is the end located on the downstream side in the rotor axis direction Da opposite to the main body part 70 . The end face 71 a of this embodiment is formed so as to face the lateral end face 461 , with a clearance left on the upstream side of the lateral end face 461 in the rotor axis direction Da.

As shown in FIG. 4 , the plurality of openings 80 a of this embodiment are formed at intervals in the circumferential direction Dc over a predetermined region of the end face 71 a . Specifically, as shown in FIG. 5 , relative to a leading edge 421 that is a region of the vane main body 42 facing the upstream side in the rotor axis direction Da, the openings 80 a of this embodiment are formed in a certain region of the end face 71 a extending in the circumferential direction Dc, at positions including a position on the upstream side of the leading edge 421 in the rotor axis direction Da. That is, the openings 80 a of this embodiment are formed in a certain area extending in the circumferential direction Dc, at positions including the position that is located on the upstream side of the leading edge 421 in the rotor axis direction Da and corresponds to the leading edge 421 , so that the position of the opening 80 a in the circumferential direction Dc corresponds to the position at which the leading edge 421 of the vane main body 42 is formed.

As shown in FIG. 5 , the first protrusion 71 has a clearance forming portion 75 that protrudes from the end face 71 a , where the openings 80 a are formed, toward the downstream side in the rotor axis direction Da. The end face of the clearance forming portion 75 facing the downstream side in the rotor axis direction Da faces the lateral end face 461 in the rotor axis direction Da. When seen from the downstream side in the rotor axis direction Da, the clearance forming portion 75 is adjacent to the end face 71 a in the circumferential direction Dc. The clearance forming portion 75 has no openings 80 a that communicate with the cooling channels 80 , and is formed intermittently in the circumferential direction, alternately with the end face 71 a , where the openings 80 a are formed, in the circumferential direction. Accordingly, if the end face of the clearance forming portion 75 facing the downstream side in the rotor axis direction Da and the lateral end face 461 come in contact with each other due to the differences in thermal elongation among the transition piece 21 , the inner shroud 45 , and the seal member 7 , a third seal surface 75 a that is a fourth end face is formed in the end face of the clearance forming portion 75 facing the downstream side in the rotor axis direction Da. However, even if the end face 71 a and the lateral end face 461 approach each other and the third seal surface 75 a and the lateral end face 461 come in contact with each other, the end face 71 a and the lateral end face 461 do not come in contact with each other, but a clearance is reliably left on the downstream side of the end face 71 a in the rotor axis direction Da.

Specifically, if the third seal surface 75 a that is the end face of the clearance forming portion 75 facing the downstream side in the rotor axis direction Da comes in contact with the lateral end face 461 in the rotor axis direction Da, a second contact part 142 that is a contact part in the first vane 41 a being the second member is formed in the lateral end face 461 facing the third seal surface 75 a . In FIG. 5 , one example of the second contact part 142 formed in the lateral end face 461 is indicated by the thick lines. The second contact part 142 is formed in the outer surface of the lateral end face 461 that comes in contact with the third seal surface 75 a in the rotor axis direction Da. However, the second contact part 142 does not have to come in contact with the entire third seal surface 75 a , and may come in contact with only a part of the third seal surface 75 a.

The second protrusion 72 is located at a position away from the first protrusion 71 , on the inner side of the first protrusion 71 in the radial direction Dr, and protrudes from the main body part 70 toward the downstream side in the rotor axis direction Da. The second protrusion 72 has a substantially rectangular parallelepiped shape of which the cross-section including the axis line Ac and spreading in the radial direction Dr is long in the rotor axis direction Da. The second protrusion 72 has an annular shape around the rotor axis Ar. The second protrusion 72 is formed at such a distance from the first protrusion 71 that the projection 424 can be inserted between the second protrusion 72 and the first protrusion 71 . A contact seal member 721 is fixed to the second protrusion 72 of this embodiment.

The contact seal member 721 is a metal sheet. The contact seal member 721 is fixed to the surface of the second protrusion 72 facing the first protrusion 71 . The contact seal member 721 has a first seal surface 721 a that is formed annularly between the contact seal member 721 and the projection 424 .

The first seal surface 721 a comes in contact with the surface of the projection 424 facing the inner side in the radial direction Dr. The first seal surface 721 a of this embodiment is the surface of the contact seal member 721 facing the first protrusion 71 located on the outer side of the contact seal member 721 in the radial direction Dr.

The third protrusion 73 protrudes from the end of the main body part 70 located on the inner side in the radial direction Dr toward the side opposite to the first protrusion 71 . The third protrusion 73 of this embodiment has a substantially rectangular parallelepiped shape of which the cross-section including the axis line Ac and spreading in the radial direction Dr is long in the rotor axis direction Da. The third protrusion 73 is formed at a position further on the inner side in the radial direction Dr than the circumferential flange portion 210 a.

The fourth protrusion 74 protrudes from the end of the third protrusion 73 located on the upstream side in the rotor axis direction Da toward the outer circumferential surface of the transition piece 21 . The fourth protrusion 74 has a substantially rectangular parallelepiped shape of which the cross-section including the axis line Ac and spreading in the radial direction Dr is long in the radial direction Dr. The fourth protrusion 74 is located at a position further on the upstream side in the rotor axis direction Da than the circumferential flange portion 210 a , and protrudes from the third protrusion 73 .

The compressed air A from inside the casing 31 of the turbine 30 is taken into the cooling channels 80 as cooling air, passed through the cooling channels 80 , and jetted out from the openings 80 a toward the lateral end face 461 . The cooling channel 80 of this embodiment has a circular cross-sectional shape. The plurality of cooling channels 80 are formed so as to penetrate the inside of the main body part 70 and the first protrusion 71 . Specifically, as shown in FIG. 6 , the cooling channel 80 of this embodiment includes an axial channel 801 and a radial channel 802 . The axial channel 801 is formed from the opening 80 a toward the upstream side in the rotor axis direction Da. The radial channel 802 communicates with the axial channel 801 on the upstream side in the rotor axis direction Da and extends toward the inner side in the radial direction Dr. Part of the combustion gas G impinging on the leading edge 421 of the vane main body 42 is entrapped into the cavity C through the clearance between the rear end 211 of the transition piece 21 and the inner shroud 45 . Accordingly, the region including the end face 71 a of the first protrusion 71 , including the position corresponding to the upstream side in the rotor axis direction Da of the leading edge 421 of the vane main body 42 , is exposed to the combustion gas G. In this region, the plurality of cooling channels 80 are disposed in the circumferential direction Dc. The cooling channels 80 are connected to the openings 80 a at the ends on the downstream side in the rotor axis direction Da. Thus, it is not necessary to dispose the cooling channels 80 over the entire region of the first protrusion 71 in the circumferential direction Dc. The cooling channels 80 should be disposed at least in some regions extending in the circumferential direction including the end face 71 a.

The axial channel 801 extends inside the first protrusion 71 , from the opening 80 a formed in the end face 71 a toward the upstream side in the rotor axis direction Da.

The radial channel 802 extends from an inflow port 80 b , formed in the surface of the main body part 70 facing the inner side in the radial direction Dr, toward the outer side in the radial direction Dr. The radial channel 802 communicates with the axial channel 801 .

The seal member 7 of this embodiment includes a first engaging part 81 connected to the transition piece 21 of the combustor 20 on the upstream side in the rotor axis direction Da, and a second engaging part 82 connected to the inner shroud 45 of the first vane 41 a on the downstream side in the rotor axis direction Da.

The first engaging part 81 seals so that the compressed air A inside the casing 31 does not leak toward the combustion gas flow passage Pg through the gap between the contact surfaces of the outlet flange 210 and the seal member 7 . The first engaging part 81 of this embodiment is composed of the main body part 70 , the third protrusion 73 , and the fourth protrusion 74 . The first engaging part 81 of this embodiment is a groove formed by the surface of the main body part 70 facing the upstream side in the rotor axis direction Da, the surface of the third protrusion 73 facing the outer side in the radial direction Dr, and the surface of the fourth protrusion 74 facing the downstream side in the rotor axis direction Da. In this embodiment, the first engaging part 81 is engaged with the outlet flange 210 of the transition piece 21 as the circumferential flange portion 210 a is fitted into the groove that is the first engaging part 81 .

A second seal surface 70 a that comes in contact with the surface of the outlet flange 210 facing the downstream side in the rotor axis direction Da is formed in the surface of the main body part 70 facing the upstream side in the rotor axis direction Da. Specifically, a differential pressure between the pressure of the compressed air A inside the casing 31 and the pressure on the side of the combustion gas flow passage Pg acts on the surface of the outlet flange 210 , facing the downstream side in the rotor axis direction Da, toward the downstream side in the rotor axis direction Da. As a result, the surface of the outlet flange 210 facing the downstream side in the rotor axis direction Da is pressed against the surface facing the upstream side in the rotor axis direction Da of the main body part 70 that is located on the downstream side of the outlet flange 210 in the rotor axis direction Da. Accordingly, during normal operation of the gas turbine, the surface of the main body part 70 facing the upstream side in the rotor axis direction Da is sealed by coming in contact with the surface of the outlet flange 210 facing the downstream side in the rotor axis direction Da. Thus, the second seal surface 70 a is formed in the surface of the main body part 70 facing the upstream side in the rotor axis direction Da. A first contact part 141 that is a contact part of the transition piece 21 being the first member is formed in the surface of the outlet flange 210 that faces the downstream side in the rotor axis direction Da and comes in contact with the second seal surface 70 a.

The second engaging part 82 seals so that the compressed air A inside the casing 31 does not leak from the gap between the projection 424 and the seal member 7 toward the combustion gas flow passage Pg. The second engaging part 82 of this embodiment is composed of the main body part 70 , the first protrusion 71 , and the second protrusion 72 . Specifically, the second engaging part 82 of this embodiment is a groove formed by the surface of the main body part 70 facing the downstream side in the rotor axis direction Da, the surface of the first protrusion 71 facing the inner side in the radial direction Dr, and the first seal surface 721 a of the second protrusion 72 . The second engaging part 82 opens toward the downstream side in the rotor axis direction Da. In this embodiment, the first seal surface 721 a comes in contact with the surface of the projection 424 facing the inner side in the radial direction Dr as the projection 424 is fitted into the groove that is the second engaging part 82 . Thus, the second engaging part 82 is engaged with the projection 424 of the inner shroud 45 .

The heat-resistant coating 130 is a coating applied to the surfaces of members exposed to the combustion gas G to enhance the heat resistance of these members. Also called a thermal barrier coating (TBC), the heat-resistant coating 130 of this embodiment functions as a protective film that suppresses thermal damage to the surfaces of the members caused by the combustion gas G. The heat-resistant coating 130 of this embodiment is formed on the transition piece 21 and the first vane 41 a.

The heat-resistant coating 130 applied to the transition piece 21 is formed to a predetermined film thickness on the inner peripheral surface 21 a of the transition piece 21 facing the combustion gas flow passage Pg, and on the first end face 101 facing the downstream side in the rotor axis direction Da, on the side of the face closer to the combustion gas flow passage Pg. The heat-resistant coating 130 formed on the first end face 101 is formed so as to extend to the inner peripheral surface 21 a from a position that is a part of the outer side of the main body first end face 111 in the radial direction Dr and close to the combustion gas flow passage Pg.

The heat-resistant coating 130 applied to the first vane 41 a is formed to a predetermined film thickness on the outer surface of the vane main body 42 , the gas path surface 441 of the inner shroud 45 , and the side of the second end face 102 closer to the combustion gas flow passage Pg. The heat-resistant coating 130 formed on the second end face 102 is formed so as to extend to the gas path surface 441 from a position that is a part of the outer side of the lateral end face 461 in the radial direction Dr and close to the combustion gas flow passage Pg.

As shown in FIG. 3 , in this embodiment, even if a difference in thermal elongation in the rotor axis direction Da occurs between the first end face 101 and the second end face 102 having the heat-resistant coatings 130 due to temperature changes of the combustion gas G flowing through the combustion gas flow passage Pg, a predetermined clearance is always secured in the rotor axis direction Da, so that these surfaces do not come in contact with each other. Specifically, as will be described later, in the case of this embodiment, even if the transition piece 21 and the first vane 41 a approach each other, the first end face 101 and the seal member 7 come in contact with each other, while the second end face 102 and the seal member 7 come in contact with each other. Thus, the transition piece 21 and the first vane 41 a indirectly come in contact with each other through the seal member 7 , but do not directly come in contact with each other. As a result, a predetermined clearance in the rotor axis direction Da is always left between the transition piece 21 and the first vane 41 a.

Specifically, the contact part 140 in the seal structure of this embodiment includes the first contact part 141 and the second contact part 142 . The first contact part 141 is formed in the surface of the outlet flange 210 (flange first end face 121 ) that forms a part of the first end face 101 and faces the downstream side in the rotor axis direction Da. The second contact part 142 is formed in the surface of the lateral end face 461 that forms a part of the second end face 102 and faces the upstream side in the rotor axis direction Da.

When the transition piece 21 and the first vane 41 a move relatively toward each other, the first end face 101 of the first contact part 141 comes in contact with the second seal surface 70 a , formed in the seal member 7 , at the first contact part 141 . When the transition piece 21 and the first vane 41 a move relatively toward each other, the second end face 102 of the second contact part 142 comes in contact with the third seal surface 75 a , formed in the seal member 7 , at the second contact part 142 . Meanwhile, a clearance is left between the first end face 101 and the second end face 102 . Thus, the first contact part 141 and the second contact part 142 restrict the relative movement of the first end face 101 and the second end face 102 in the rotor axis direction Da through the seal member 7 .

Specifically, when the transition piece 21 and the first vane 41 a move relatively in the rotor axis direction Da so as to come closest to each other, the first contact part 141 is in contact with the second seal surface 70 a of the seal member 7 . In this state, the second contact part 142 is at the same time in contact with the third seal surface 75 a of the seal member 7 . However, even in this case, a certain clearance is always left between the first end face 101 and the second end face 102 . In other words, if the transition piece 21 being the first member and the first vane 41 a being the second member move relatively toward each other, a clearance is left between the first end face 101 and the second end face 102 that have the heat-resistant coatings 130 . In this state, the transition piece 21 being the first member and the first vane 41 a being the second member are in contact with each other through the seal member 7 being the third member, further on the outer side of the combustion gas flow passage Pg (the inner side or the outer side in the radial direction Dr) than the heat-resistant coatings 130 . Thus, in this embodiment, the transition piece 21 and the first vane 41 a are indirectly in contact with each other through the contact part 140 composed of the first contact part 141 and the second contact part 142 .

Thus, if the transition piece 21 and the first vane 41 a move relatively in the rotor axis direction Da so as to approach each other, the contact part 140 (the first contact part 141 , the second contact part 142 ) of the first embodiment leaves a clearance between the first end face 101 ( 111 ) and the lateral end face 461 . In this state, the contact part 140 restricts the relative movement of the transition piece 21 and the first vane 41 a in the rotor axis direction Da.

Next, the workings of the gas turbine 1 having the above configuration will be described.

According to the gas turbine 1 of this embodiment, the compressed air A from the compressor 10 enters inside the casing 31 of the turbine 30 and flows into the combustor 20 . In the combustor 20 , fuel supplied from the outside is combusted along with the compressed air A inside the combustor basket 22 a to generate the combustion gas G. The combustion gas G flows through the transition piece 21 into the combustion gas flow passage Pg of the turbine 30 . While passing through the combustion gas flow passage Pg, the combustion gas G comes in contact with the blade main bodies 37 and rotates the turbine rotor 33 around the rotor axis Ar.

When flowing from the transition piece 21 into the combustion gas flow passage Pg, the combustion gas G impinges on the leading edge 421 of the vane main body 42 . Thus, part of the combustion gas is entrapped and flows into the cavity C through the clearance formed between the rear end 211 of the transition piece 21 and the inner shroud 45 . As a result, the surfaces of the main body part 70 and the first protrusion 71 of the seal member 7 facing the combustion gas flow passage Pg are exposed to the high-temperature combustion gas G.

During operation of the gas turbine 1 , the pressure inside the casing 31 is higher than the pressure inside the cavity C communicating with the combustion gas flow passage Pg. Accordingly, the surface of the main body part 70 of the seal member 7 facing the upstream side in the rotor axis direction Da and the surface of the outlet flange 210 facing the downstream side in the rotor axis direction Da come in contact with each other at the first contact part 141 and the second seal surface 70 a . Moreover, the first seal surface 721 a of the contact seal member 721 fixed to the second protrusion 72 and the surface of the projection 424 located on the inner side in the radial direction Dr come in contact with each other. Thus, the space inside the casing 31 and the cavity C are sealed off from each other.

Specifically, the first seal surface 721 a of the contact seal member 721 provided in the second protrusion 72 is pressed against the surface of the projection 424 facing the inner side in the radial direction Dr. The second seal surface 70 a is pressed against the surface of the circumferential flange portion 210 a facing the downstream side in the rotor axis direction Da. Thus, the gap between the first seal surface 721 a and the surface of the projection 424 facing the inner side in the radial direction Dr is sealed. Moreover, the gap between the second seal surface 70 a and the surface of the circumferential flange portion 210 a facing the downstream side in the rotor axis direction Da are sealed.

In this state, part of the compressed air A supplied from the compressor 10 into the casing 31 flows into the cooling channels 80 of the seal member 7 and thereby cools the seal member 7 itself. Specifically, the compressed air A inside the casing 31 flows from the inflow port 80 b into the radial channel 802 , flows through the axial channel 801 , and jets out of the opening 80 a into the cavity C. As a result, the main body part 70 and the first protrusion 71 exposed to the combustion gas G are cooled.

According to the seal structure 100 as has been described above, the contact part 140 (the first contact part 141 and the second contact part 142 ) restricts the relative movement of the transition piece 21 and the first vane 41 a in the rotor axis direction Da toward each other by coming in contact with the lateral end face 461 in a state where a clearance is left between the main body first end face 111 (first end face 101 ) and the lateral end face 461 . As a result, it is possible to prevent contact between the heat-resistant coating 130 formed on the main body first end face 111 and the heat-resistant coating 130 formed on the lateral end face 461

Specifically, during startup or shutdown of operation of the gas turbine, the main body first end face 111 and the lateral end face 461 come in contact with each other due to the difference in thermal elongation between the transition piece 21 and the inner shroud 45 . This may result in damage to the heat-resistant coatings 130 .

In the first embodiment, however, before the main body first end face 111 and the lateral end face 461 directly come in contact with each other, the contact part 140 (the first contact part 141 and the second contact part 142 ) comes in contact with the region of the lateral end face 461 on the outer side in the radial direction Dr where the heat-resistant coating 130 is not formed. Thus, the relative movement of the transition piece 21 and the first vane 41 a in the rotor axis direction Da can be restricted by the seal member 7 so that the main body first end face 111 and the lateral end face 461 do not approach each other in the rotor axis direction Da. It is therefore possible to prevent direct contact between the main body first end face 111 of the transition piece 21 on which the heat-resistant coating 130 is formed and the lateral end face 461 of the adjacent first vane 41 a on which the heat-resistant coating 130 is formed. Accordingly, damage to the heat-resistant coatings 130 can be prevented.

The first member in the seal structure 100 is the transition piece 21 of the combustor 20 . The second member is the first vane 41 a adjacent to the downstream side of the transition piece 21 in the rotor axis direction Da. The third member is the seal member 7 disposed between the transition piece 21 and the first vane 41 a . Thus, the seal structure 100 that can protect the heat-resistant coating 130 in the vicinity of the outlet opening of the transition piece 21 can be easily employed.

The clearance forming portion 75 protruding from the end face 71 a of the seal member 7 toward the downstream side in the rotor axis direction Da is provided. Thus, even if the end face 71 a and the lateral end face 461 of the inner shroud 45 approach each other, the openings 80 a can be prevented from being blocked.

Specifically, in this embodiment, the clearance forming portion 75 protrudes further toward the downstream side in the rotor axis direction Da than the end face 71 a where the openings 80 a are formed. Thus, even if the clearance between the end face 71 a of the first protrusion 71 and the lateral end face 461 of the inner shroud 45 is reduced, before the openings 80 a are blocked, the third seal surface 75 a formed in the end face of the clearance forming portion 75 located on the downstream side in the rotor axis direction Da comes in contact with the second contact part 142 formed in the lateral end face 461 . Thus, a space can be stably secured on the downstream side of the openings 80 a in the rotor axis direction Da. It is therefore possible to stably and continuously discharge the required cooling air from the openings 80 a , even if the clearance between the end face 71 a and the lateral end face 461 is reduced.

Accordingly, the openings 80 a can be prevented from being blocked. Thus, the compressed air A as cooling air can be stably passed through the axial channel 801 and the radial channel 802 . As a result, the seal member 7 can be stably cooled.

The openings 80 a provided in the end face 71 a are formed in a certain region extending in the circumferential direction Dc, at positions including the position that is, relative to the position in the circumferential direction Dc at which the leading edge 421 of the vane main body 42 is formed, located on the upstream side in the rotor axis direction Da and corresponds to that position. Thus, it is possible to partially and effectively cool the vicinity of the leading edge 421 that tends to reach a high temperature as the combustion gas G flowing from the transition piece 21 into the combustion gas flow passage Pg impinges on the leading edge 421 .

Specifically, the combustion gas G impinges on the leading edge 421 . As a result, part of the combustion gas G is more likely to flow into the cavity C through the clearance between the rear end 211 of the transition piece 21 and the end face 71 a of the inner shroud 45 , in the part located on the upstream side of the leading edge 421 in the rotor axis direction Da than in the other part in the circumferential direction Dc. Thus, in the part located on the upstream side of the leading edge 421 in the rotor axis direction Da, the main body part 70 and the first protrusion 71 reach higher temperatures due to the entrapped combustion gas G.

For this reason, the plurality of cooling channels 80 are disposed in the circumferential direction Dc in the first protrusion 71 that is a certain region in the circumferential direction Dc, at positions including the position corresponding to the upstream side of the leading edge 421 in the rotor axis direction Da, and the openings 80 a are provided at the ends of the cooling channels 80 on the downstream side in the axial direction. This makes it possible to efficiently supply cooling air to the part of the main body part 70 and the first protrusion 71 that reaches a higher temperature, and to thereby cool the seal member 7 in the circumferential direction Dc. As a result, the flow rate of cooling air passed through the cooling channels 80 to cool the main body part 70 and the first protrusion 71 of the seal member 7 can be reduced. Accordingly, the flow rate of the compressed air A used as cooling air can be reduced, so that performance degradation of the gas turbine 1 can be suppressed.

Second Embodiment

Next, a seal structure 200 of a second embodiment will be described with reference to FIG. 7 and FIG. 8 .

In the second embodiment, the same components as in the first embodiment will be given the same reference signs and a detailed description thereof will be omitted. The seal structure 200 of the second embodiment is different from the seal structure of the first embodiment in that the former is formed in the ring segments 60 adjacent to each other in the circumferential direction Dc.

The seal structure 200 according to the second embodiment of the present invention will be described below. FIG. 7 shows the structure of the ring segment 60 in cross-section as seen from the circumferential direction Dc. FIG. 8 shows the structure of the ring segments 60 in cross-section as seen from the rotor axis direction Da.

The seal structure 200 of the second embodiment is used for the ring segments 60 adjacent to each other in the circumferential direction Dc. The seal structure 200 of the second embodiment relates to a structure for sealing the gap between a pair of ring segments 60 adjacent to each other in the circumferential direction Dc, without causing damage to thermal barrier coatings formed on the pair of ring segments 60 .

As shown in FIG. 7 , the ring segment 60 has a ring segment main body 61 , an upstream-side hook 62 , and a downstream-side hook 63 . The ring segment main body 61 spreads in the circumferential direction Dc. The upstream-side hook 62 extends from the upstream side of the ring segment main body 61 in the rotor axis direction Da toward the outer side in the radial direction Dr. The downstream-side hook 63 extends from the downstream side of the ring segment main body 61 in the rotor axis direction Da toward the outer side in the radial direction Dr.

The ring segment main body 61 is mounted on the heat shield ring 52 through the upstream-side hook 62 and the downstream-side hook 63 and supported on the blade ring 50 . The ring segment main body 61 has a ring segment gas path surface 610 facing the combustion gas flow passage Pg and lateral surfaces intersecting with the ring segment gas path surface 610 . The ring segment main body 61 has an upstream-side end face 611 facing the upstream side in the rotor axis direction Da and a downstream-side end face 612 facing the downstream side in the rotor axis direction Da.

Cooling channels extending in the rotor axis direction Da are formed in the ring segment main body 61 . Specifically, as the cooling channels, an upstream-side channel 611 b and a downstream-side channel 612 b are formed inside the ring segment main body 61 . The upstream-side channel 611 b extends in the rotor axis direction Da, from the surface that is located on the side opposite to the ring segment gas path surface 610 and faces the outer side in the radial direction Dr toward an upstream-side opening 611 a . The downstream-side channel 612 b extends in the rotor axis direction Da, from the surface that is located on the side opposite to the ring segment gas path surface 610 and faces the outer side in the radial direction Dr toward a downstream-side opening 612 a . These cooling channels are merely an example, and the cooling channels are not limited to this example.

Here, the front side in the rotation direction of the blades 36 rotating around the rotor axis Ar will be referred to as the front side in the circumferential direction Dc (the left side in the sheet of FIG. 8 ), and the rear side in the rotation direction will be referred to as the rear side in the circumferential direction Dc (the right side in the sheet of FIG. 8 ).

The ring segment 60 has a front engaging part 65 provided on the front side in the circumferential direction Dc of the adjacent ring segment main body 61 , and the rear engaging part 64 provided on the rear side in the circumferential direction Dc of the adjacent ring segment main body 61 . In this embodiment, as shown in FIG. 8 , the pair of ring segments 60 adjacent to each other in the circumferential direction Dc will be taken as an example to describe the front engaging part 65 and the rear engaging part 64 .

The rear engaging part 64 has a rear end face 641 that intersects with the ring segment gas path surface 610 and faces the front side in the circumferential direction Dc. The rear engaging part 64 has a protrusion 642 that protrudes in the circumferential direction Dc from the rear end face 641 , and a rear groove 643 that is recessed from the rear end face 641 in the circumferential direction Dc and extends in the rotor axis direction Da.

The protrusion 642 protrudes from the rear end face 641 toward the front side in the circumferential direction Dc so as to face the combustion gas flow passage Pg. In the protrusion 642 , the surface on the side closer to the combustion gas flow passage Pg is formed as a member that extends the ring segment gas path surface 610 toward the front side in the circumferential direction Dc. In the protrusion 642 , a protrusion end face 642 a facing the front side in the circumferential direction Dc is formed on the leading end side in the protrusion direction. On the side of the protrusion end face 642 a closer to the combustion gas flow passage Pg, a main body lateral outer surface 61 a recessed from the protrusion end face 642 a toward the rear side in the circumferential direction Dc is formed. The main body lateral outer surface 61 a forms a part of the protrusion end face 642 a . The main body lateral outer surface 61 a is connected through a smooth surface to a main body outer surface 61 b that spreads along the ring segment gas path surface 610 of the ring segment main body 61 . The surfaces of the main body lateral outer surface 61 a and the main body outer surface 61 b are covered with a ring segment heat-resistant coating 230 to be described later.

The rear groove 643 is formed on the outer side of the combustion gas flow passage Pg. Specifically, the rear groove 643 is formed further on the outer side in the radial direction Dr than the protrusion 642 . The rear groove 643 is an angular groove depressed from the rear end face 641 toward the rear side in the circumferential direction Dc.

The front engaging part 65 has a front end face 651 that intersects with the ring segment gas path surface 610 and faces the rear side in the circumferential direction Dc. The front end face 651 faces the rear end face 641 of the adjacent ring segment 60 across a distance. The front engaging part 65 has a recess 652 that is recessed from the front end face 651 toward the front side in the circumferential direction Dc, and a front groove 653 that is recessed from the front end face 651 toward the front side in the circumferential direction Dc and extends in the rotor axis direction Da.

In a cross-section seen from the rotor axis direction Da, the recess 652 has a shape recessed at a corner so that the protrusion 642 can be fitted from the circumferential direction Dc. The recess 652 is formed at the corner where the ring segment gas path surface 610 and the front end face 651 intersect with each other. The recess 652 has a recess end face 652 a that is located further on the front side in the circumferential direction Dc than the front end face 651 and faces the rear side in the circumferential direction Dc. As in the protrusion 642 , a main body lateral outer surface 61 a recessed from the recess end face 652 a toward the front side in the circumferential direction Dc is formed in the recess end face 652 a , on the side of the face closer to the combustion gas flow passage Pg. The main body lateral outer surface 61 a forms a part of the recess end face 652 a . The main body lateral outer surface 61 a is connected through a smooth surface to the main body outer surface 61 b that spreads along the ring segment gas path surface 610 of the ring segment main body 61 . The surfaces of the main body lateral outer surface 61 a and the main body outer surface 61 b are covered with the ring segment heat-resistant coating 230 to be described later.

The front groove 653 is formed on the outer side of the combustion gas flow passage Pg. Specifically, the front groove 653 is formed further on the outer side in the radial direction Dr than the recess 652 . The front groove 653 is formed at the same position in the radial direction Dr as the rear groove 643 . The front groove 653 is an angular groove depressed toward the front side in the circumferential direction Dc.

An impingement plate 9 supported by the heat shield ring 52 is provided between the outer side of the ring segment 60 in the radial direction Dr and the casing 31 . The impingement plate 9 has a sheet-like shape, and has a plurality of air holes 9 a penetrating the impingement plate 9 in the radial direction Dr toward the ring segment 60 .

The seal structure 200 of the second embodiment includes the front engaging part 65 of one ring segment 60 a , the rear engaging part 64 of the other ring segment 60 b , a seal plate 250 , the ring segment heat-resistant coating 230 , and a ring segment contact part 240 . The front engaging part 65 is disposed on the front side in the circumferential direction Dc in the pair of adjacent ring segments 60 . The rear engaging part 64 is disposed on the rear side in the circumferential direction Dc. The seal plate 250 is disposed between the front engaging part 65 and the rear engaging part 64 . The ring segment heat-resistant coating 230 is formed on the surfaces of the ring segments 60 exposed to the combustion gas G. The ring segment contact part 240 restricts the relative movement of the pair of adjacent ring segments 60 toward each other.

In the seal structure 200 of the second embodiment, the rear engaging part 64 of the one ring segment 60 b of the pair of ring segments 60 adjacent to each other in the circumferential direction corresponds to a first member. In the seal structure 200 , the front engaging part 65 of the other ring segment 60 a adjacent to the rear side of the ring segment 60 a in the circumferential direction Dc corresponds to a second member.

Accordingly, the face of the rear engaging part 64 facing the front side in the circumferential direction Dc is a first end face 201 in the second embodiment. The face of the front engaging part 65 facing the rear side in the circumferential direction Dc is a second end face 202 in the second embodiment. The first end face 201 of the second embodiment is the rear end face 641 and the protrusion end face 642 a . The second end face 202 of the second embodiment is the front end face 651 and the recess end face 652 a.

The seal plate 250 is disposed between the front end face 651 and the rear end face 641 . The seal plate 250 is a seal member that seals the gap between the front end face 651 and the rear end face 641 through the front groove 653 and the rear groove 643 . The seal plate 250 is a third member in the seal structure 200 of the second embodiment. The seal plate 250 engages with the adjacent ring segments 60 between the rear end face 641 that is the first end face 201 and the front end face 651 that is the second end face 202 .

The seal plate 250 of this embodiment is disposed on the outer side of the combustion gas flow passage Pg through which the combustion gas G flows. As shown in FIG. 8 , the seal plate 250 is inserted into the rear groove 643 of the rear end face 641 and the front groove 653 of the front end face 651 . The seal plate 250 has a rectangular shape in a longitudinal section orthogonal to the rotor axis Ar. The seal plate 250 extends in the rotor axis direction Da.

The ring segment heat-resistant coating 230 is a TBC film applied to the surfaces of the ring segments 60 to enhance the heat resistance of members exposed to the combustion gas G. The ring segment heat-resistant coating 230 of this embodiment is formed to a predetermined film thickness as with the heat-resistant coating 130 of the first embodiment.

As described above, the ring segment heat-resistant coating 230 is formed on the main body lateral outer surface 61 a of the ring segment main body 61 . Specifically, the ring segment heat-resistant coating 230 is formed on the main body lateral outer surface 61 a , on the side of the protrusion end face 642 a closer to the combustion gas flow passage Pg that is the side closer to the ring segment gas path surface 610 , with the position recessed from the protrusion end face 642 a toward the rear side in the circumferential direction Dc serving as a border. Similarly, in the recess end face 652 a facing the protrusion end face 642 a in the circumferential direction Dc, the ring segment heat-resistant coating 230 is formed on the main body lateral outer surface 61 a , on the side of the recess end face 652 a closer to the combustion gas flow passage Pg that is the side closer to the ring segment gas path surface 610 , with the position recessed from the recess end face 652 a toward the front side in the circumferential direction Dc serving as a border. At the border in each of the protrusion end face 642 a and the recess end face 652 a , the heat-resistant coating 230 has such a film thickness that the coating does not protrude toward the front side or the rear side in the circumferential direction Dc from the protrusion end face 642 a or the recess end face 652 a extending in the circumferential direction Dc. Thus, even if the protrusion end face 642 a and the recess end face 652 a come in contact with each other in the circumferential direction Dc, the adjacent heat-resistant coatings 230 do not come in contact with each other in the circumferential direction Dc. As a result, a slight clearance is always left in the circumferential direction Dc.

The ring segment contact part 240 is disposed on the outer side of the ring segment heat-resistant coatings 230 relative to the combustion gas flow passage Pg. The ring segment contact part 240 of the second embodiment is disposed at a position farther away from the combustion gas flow passage Pg than the position at which the ring segment heat-resistant coatings 230 of the protrusion end face 642 a and the recess end face 652 a are formed. When the pair of adjacent ring segments 60 move toward each other in the circumferential direction Dc, the ring segment contact part 240 leaves a clearance between the ring segment heat-resistant coatings 230 adjacent to each other in the circumferential direction Dc. In this state, the protrusion end face 642 a and the recess end face 652 a disposed on the outer side of the combustion gas flow passage Pg come in contact with each other in the circumferential direction Dc. As a result, the ring segment contact part 240 restricts the relative movement of the pair of ring segments 60 in the circumferential direction Dc.

The ring segment contact part 240 of the second embodiment includes a first contact part 241 formed in the recess end face 652 a and a second contact part 242 formed in the protrusion end face 642 a.

In the region of the protrusion end face 642 a where the ring segment heat-resistant coating 230 is formed, a plurality of cooling channels (front-side channels 642 c ) are formed at intervals in the rotor axis direction Da. The cooling channel (front-side channel 642 c ) has one end communicating with a ring segment cavity and the other end connecting to a rear-side opening 642 b having a circular shape. In the region of the recess end face 652 a where the ring segment heat-resistant coating 230 is formed, a plurality of cooling channels (rear-side channels 652 c ) are formed at intervals in the rotor axis direction Da. The cooling channel (rear-side channel 652 c ) has one end communicating with the ring segment cavity and the other end connecting to a front-side opening 652 b having a circular shape.

Next, the workings of the gas turbine 1 having the above configuration will be described.

According to the gas turbine 1 of this embodiment, part of the compressed air A from the compressor 10 , or the compressed air A extracted from the compressor 10 , is also supplied as cooling air to the regions on the outer side of the outer shroud 43 in the radial direction Dr and the inner side of the inner shroud 45 in the radial direction Dr to cool the outer shroud 43 and the inner shroud 45 of the vane 41 . That part of the compressed air A, or that compressed air A extracted from the compressor 10 , flowing from the compressor 10 into the casing 31 is also supplied to the regions on the inner side of the casing 31 in the radial direction Dr that is the outer side of the blade ring 50 in the radial direction Dr. To cool the ring segments 60 , the compressed air A flows through the blade ring 50 toward the outer side in the radial direction Dr of the ring segments 60 that are disposed on the inner side of the blade ring 50 in the radial direction Dr.

The compressed air A supplied to the outer side of the ring segment 60 in the radial direction Dr blows out through the plurality of air holes 9 a in the impingement plate 9 toward the inner side in the radial direction Dr, and thereby performs impingement cooling on the surface of the ring segment main body 61 on the outer side in the radial direction Dr. After performing impingement cooling, the compressed air A flows into the upstream-side channel 611 b and the downstream-side channel 612 b of the ring segment main body 61 . Thereafter, the compressed air A flows toward the upstream side and the downstream side in the rotor axis direction Da, and thereby perform convection cooling on the upstream-side end face 611 and the downstream-side end face 612 .

After performing impingement cooling, the compressed air A flows into the front-side channels 642 c and the rear-side channels 652 c and flows toward the front side and the rear side in the circumferential direction Dc, thereby performing convection cooling on the protrusion end face 642 and the recess end face 652 a.

According to the seal structure 200 as has been described above, the first contact part 241 formed in the recess end face 652 a and the second contact part 242 formed in the protrusion end face 642 a come in contact with each other in the state where a clearance is left between the ring segment heat-resistant coatings 230 of the ring segments 60 adjacent to each other in the circumferential direction Dc. Thus, the relative movement of the adjacent ring segments 60 a , 60 b in the circumferential direction Dc toward each other is restricted. As a result, it is possible to prevent contact between the ring segment heat-resistant coating 230 formed on the recess end face 652 a and the ring segment heat-resistant coating 230 formed on the protrusion end face 642 a.

Specifically, in the second embodiment, the ring segment heat-resistant coatings 230 are formed further on the side closer to the combustion gas flow passage Pg than the first contact part 241 and the second contact part 242 , with the first contact part 241 and the second contact part 242 serving as the borders. The ring segment heat-resistant coatings 230 are formed to such a film thickness that the coatings do not protrude in the circumferential direction Dc beyond the first contact part 241 and the second contact part 242 . Thus, even if the first contact part 241 formed in the recess end face 652 a and the second contact part 242 formed in the protrusion end face 642 a come in contact with each other, the first contact part 241 and the second contact part 242 do not come in contact with the ring segment heat-resistant coatings 230 , but a slight clearance is left therebetween, so that no damage is caused to the ring segment heat-resistant coatings 230 . That is, even if the ring segments 60 a , 60 b adjacent to each other in the circumferential direction Dc move toward each other in the circumferential direction Dc and the recess end face 652 a and the protrusion end face 642 a are about to come in contact with each other, the first contact part 241 and the second contact part 242 first come in contact with each other. As a result, a situation is avoided where the recess end face 652 a and the protrusion end face 642 a further approach each other and directly come in contact with the ring segment heat-resistant coatings 230 .

The high-temperature combustion gas G entrapped by the rotation of the blades 36 is retained in the clearance located further on the inner side in the radial direction Dr than the seal plate 250 , between the recess end face 652 a and the protrusion end face 642 a of the adjacent ring segments 60 a , 60 b . Accordingly, the outer surface temperatures of the ring segments 60 a , 60 b rise, and oxidation thinning is likely to progress at the corners of the ring segments 60 a , 60 b . In this embodiment, however, the rear-side channels 652 c and the front-side channels 642 c are formed respectively in the recess end face 652 a and the protrusion end face 642 a of the ring segments 60 a , 60 b adjacent to each other in the circumferential direction Dc. Thus, the compressed air A is jetted out of the rear-side openings 642 b and the front-side openings 652 b so as to hit and cool the opposite recess end face 652 a and protrusion end face 642 a . It is therefore possible to promote the cooling of the corners of the ring segments 60 a , 60 b between the recess end face 652 a and the protrusion end face 642 a where the high-temperature combustion gas G is intensively entrapped and retained.

The first member in the seal structure 200 is the rear engaging part 64 of the one ring segment 60 b disposed on the front side in the circumferential direction Dc. The second member is the front engaging part 65 of the other ring segment 60 a disposed on the rear side in the circumferential direction Dc. The third member is the seal plate 250 . Thus, the seal structure 200 that can protect the ring segment heat-resistant coatings 230 can be easily employed between the pair of ring segments 60 a , 60 b adjacent to each other in the circumferential direction.

While the embodiments of the present invention have been described above in detail with reference to the drawings, the components, the combinations thereof, etc. in each embodiment are merely examples, and addition, omission, substitution, and other changes can be made to these components within the scope of the gist of the present invention.

The contact part 140 of the first embodiment is not limited to the form in which the contact part 140 is disposed adjacent to the openings 80 a in the circumferential direction Dc as in the embodiment. The contact part 140 of the first embodiment should at least be able to leave a space between the end face 71 a where the openings 80 a are provided and the lateral end face 461 of the inner shroud 45 so as not to block the openings 80 a . For example, the contact part 140 of the first embodiment may be formed adjacent to the openings 80 a in the radial direction Dr, or may be formed in the second protrusion 72 or the main body part 70 .

The openings 80 a provided in the seal member 7 of the first embodiment are not limited to the form in which the openings 80 a are formed on the upstream side in the rotor axis direction Da of the leading edge 421 of the vane main body 42 as in the embodiment. The openings 80 a should be formed at least in array in the circumferential direction Dc. For example, the openings 80 a may be formed at equal intervals in the circumferential direction Dc, or may be formed in areas other than the upstream side of the leading edge 421 in the rotor axis direction Da.

In the first embodiment, the openings 80 a formed in array in the circumferential direction Dc have the same shape, but the openings 80 a are not limited to this example. The openings 80 a may have an arbitrary shape according to the position in the circumferential direction Dc. For example, the openings 80 a that are formed on the upstream side of the leading edge 421 in the rotor axis direction Da may be of a larger size, while the openings 80 a that are formed at positions other than the upstream side of the leading edge 421 in the rotor axis direction Da may be of a smaller size.

In the first embodiment, the cooling channels 80 may be formed in the transition piece 21 or the first vane 41 a . For example, the cooling channels 80 having the openings 80 a in the main body first end face 111 that is the first end face 101 of the first embodiment, or the cooling channels 80 having the openings 80 a in the lateral end face 461 that is the second end face 102 may be formed.

The contact part 140 is not limited to the form of the contact part in the first embodiment or the second embodiment. The contact part 140 should at least be able to restrict the relative movement of the first member and the second member toward each other by coming in contact with one of the first end face 101 and the second end face 102 on the outer side of the heat-resistant coatings 130 .

For example, as in the ring segment 60 b that is the second member in the second embodiment, the contact part 140 may also be provided in the first vane 41 a in addition to the contact part 140 provided in the seal member 7 that is the third member in the first embodiment.

Instead of the pair of adjacent ring segments 60 a , 60 b being provided respectively with the first contact part 241 and the second contact part 242 as in the second embodiment, only one of the first contact part 241 and the second contact part 242 may be provided. The first contact part 241 and the second contact part 242 may be provided in the front end face 651 or the rear end face 641 instead of in the recess end face 652 a and the protrusion end face 642 a.

According to the seal structure 100 described above, before the first end face 101 and the second end face 102 come in contact with each other, the contact part 140 comes in contact with the region of the first end face 101 where the heat-resistant coating 130 is not formed. Thus, it is possible to prevent contact between the first end face 101 of the first member on which the heat-resistant coating 130 is formed and the second end face 102 of the second member, adjacent to the first member, on which the heat-resistant coating 130 is formed.

1 Gas turbine

A Compressed air

10 Compressor

20 Combustor

Ac Axis line

21 Transition piece (first member)

21 a Inner circumferential surface

210 Outlet flange

210 a Circumferential flange portion

211 Rear end

22 Fuel supply unit

22 a Combustor basket

30 Turbine

Da Rotor axis direction

Dc Circumferential direction

Dr Radial direction

31 Casing

Ar Rotor axis

33 Turbine rotor

34 Rotor main body

35 Blade row

36 Blade

37 Blade main body

38 Platform

39 Blade root

40 Vane row

41 Vane

42 Vane main body

43 Outer shroud

45 Inner shroud

40 a First vane row

41 a First vane (second member)

421 Leading edge

44 Shroud main body

441 Gas path surface

46 Lateral wall

461 Lateral end face

424 Projection

50 Blade ring

52 Heat shield ring

60 Ring segment (first member, second member)

G Combustion gas

Pg Combustion gas flow passage

100 , 200 Seal structure

101 , 201 First end face

111 Main body first end face

121 Flange first end face

102 , 202 Second end face

112 Projection second end face

7 Seal member (third member)

C Cavity

70 Main body part

70 a Second seal surface

71 First protrusion

71 a End face (third end face)

72 Second protrusion

721 Contact seal member

721 a First seal surface

73 Third protrusion

74 Fourth protrusion

75 Clearance forming portion

75 a Third seal surface (fourth end face)

80 Cooling channel

801 Axial channel

802 Radial channel

80 a Opening

80 b Inflow port

81 First engaging part

82 Second engaging part

130 Heat-resistant coating

140 Contact part

141 First contact part

142 Second contact part

9 Impingement plate

9 a Air hole

61 Ring segment main body

61 a Main body lateral outer surface

61 b Main body outer surface

610 Ring segment gas path surface

611 Upstream-side end face

611 a Upstream-side opening

611 b Upstream-side channel

612 Downstream-side end face

612 a Downstream-side opening

612 b Downstream-side channel

62 Upstream-side hook

63 Downstream-side hook

64 Rear engaging part

641 Rear end face

642 Protrusion

642 a Protrusion end face

642 b Rear-side opening

642 c Front-side channel

643 Rear groove

65 Front engaging part

651 Front end face

652 Recess

652 a Recess end face

652 b Front-side opening

652 c Rear-side channel

653 Front groove

230 Ring segment heat-resistant coating

240 Ring segment contact part

241 First contact part

242 Second contact part

250 Seal plate (third member)