Fixed blade and gas turbine provided with same

Abstract

The fixed blade has a blade body, a plurality of blade air passages, and a plurality of rear end air passages. The plurality of blade air passages are arranged from the leading edge side toward the trailing edge side of the blade body. The plurality of rear end air passages have a rear edge opening that extends from a rear blade air passage closest to the rear edge side among the plurality of blade air passages toward the rear edge and opens on the rear edge. In the trailing edge extending in the blade height direction, a region including an end portion of the blade height first side and not including an end portion of the blade height second side is defined as a first side region. A region separated from the first side region toward the blade height second side in the trailing edge and including an end portion of the blade height second side is defined as a second side region. And the first side region is higher than the second side region with respect to the opening ratio of the trailing edge openings in the plurality of rear end air passages, where the opening area per unit length of the trailing edge in the blade height direction of the trailing edge openings in the plurality of rear end air passages is defined as the opening ratio.

Description

Technical Field

[0001] The present invention relates to a stationary blade and a gas turbine including the stationary blade.

[0002] This application claims priority based on patent application No. 2022-105877 filed in Japan on June 30, 2022, and the contents are incorporated herein by reference. Background Art

[0003] The gas turbine comprises a compressor for compressing air to generate compressed air, a burner for burning fuel in the compressed air to generate combustion gas, and a turbine driven by the combustion gas. The turbine comprises a turbine rotor that rotates around an axis, a turbine casing that covers the rotor, and a plurality of fixed blade rows. The turbine rotor comprises a rotor shaft centered around the axis and a plurality of rotating blade rows mounted on the rotor shaft. The plurality of rotating blade rows are arranged in the axial direction in which the axis extends. Each rotating blade row has a plurality of rotating blades arranged in the circumferential direction relative to the axis. The plurality of fixed blade rows are arranged in the axial direction and are mounted on the inner circumference of the turbine casing. The plurality of fixed blade rows are respectively arranged on the axial upstream side of any one of the plurality of rotating blade rows. Each fixed blade row has a plurality of fixed blades arranged in the circumferential direction relative to the axis.

[0004] The fixed blade has: a blade body, which has a blade shape in a cross section perpendicular to the radial direction relative to the axis and extends in the radial direction; an inner shroud, which is arranged radially inside the blade body; and an outer shroud, which is arranged radially outside the blade body. The blade body of the fixed blade is arranged in a combustion gas flow path through which the combustion gas passes. The inner shroud defines the radial inner edge of the combustion gas flow path. The outer shroud defines the radial outer edge of the combustion gas flow path.

[0005] The stationary blades of the gas turbine are exposed to high-temperature combustion gas, and therefore, the stationary blades are generally cooled by air or the like.

[0006] For example, in the blade body of the fixed blade described in the following patent document 1, a plurality of blade air passages and a plurality of trailing edge air passages through which cooling air can flow are formed. The plurality of blade air passages all extend radially. The plurality of blade air passages are arranged from the leading edge side to the trailing edge side of the blade body. In the blade air passage closest to the leading edge among the plurality of blade air passages, i.e., the front blade air passage, the radially outer end of the front blade air passage constitutes an inlet opening. The radially inner portions of the blade air passages adjacent to the front blade air passage on the trailing edge side among the plurality of blade air passages, i.e., the rear cooling passages, are connected to the front blade air passage. The plurality of trailing edge air passages are arranged radially. The plurality of trailing edge air passages all extend from the rear blade air passage toward the trailing edge and open at the trailing edge.

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 8-319852 Summary of the invention

[0010] Technical issues to be solved by the invention

[0011] Regarding the stationary blades of the gas turbine, it is desired to cool the stationary blades to improve the durability of the stationary blades while suppressing the amount of air used for cooling the stationary blades.

[0012] Therefore, an object of the present invention is to provide a stationary blade capable of effectively cooling with cooling air to improve durability while suppressing the amount of cooling air used, and a gas turbine including the stationary blade.

[0013] Means for solving technical problems

[0014] In a fixed blade of one mode of the invention for achieving the above-mentioned purpose, it is a fixed blade provided for a gas turbine, and the fixed blade comprises: a blade body having a blade-shaped cross-sectional shape and extending in a blade height direction having a directional component perpendicular to the cross-section; an outer shroud arranged on the first blade height side of the blade body in the blade height direction and on the second blade height side, and configured to be mountable on a turbine casing; a plurality of blade air passages extending in the blade body in the blade height direction; and a plurality of rear end air passages arranged in the blade height direction.

[0015] The blade body has a leading edge and a trailing edge extending in the blade height direction. The plurality of blade air passages are arranged from the leading edge side toward the trailing edge side. The blade air passage closest to the leading edge among the plurality of blade air passages, i.e., the front blade air passage, has an inlet opening into which cooling air can flow at the end of the front blade air passage on the first side of the blade height. The blade air passages adjacent to each other among the plurality of blade air passages are connected to each other at one end of the end on the first side of the blade height and the end on the second side of the blade height, so that the plurality of blade air passages constitute a serpentine passage in which the passages are undulating in the blade height direction. The plurality of rear end air passages have a trailing edge opening, which extends from the blade air passage closest to the trailing edge among the plurality of blade air passages, i.e., the rear blade air passage, toward the trailing edge and opens at the trailing edge. A region including the end on the first side of the blade height and excluding the end on the second side of the blade height in the trailing edge extending in the blade height direction is set as a first side region. A region in the trailing edge separated from the first side region to the second side of the blade height and including the end on the second side of the blade height is set as a second side region. The opening area per unit length of the trailing edge of the plurality of rear air passages in the blade height direction is defined as an opening ratio. At this time, the first side region has a higher opening ratio of the trailing edge openings in the plurality of rear air passages than the second side region.

[0016] In recent years, in order to improve the performance of gas turbines, methods of increasing the blade height of the blade body (in other words, extending the radial length of the blade body) are being studied. If the radial length of the blade body is extended, the force on the blade body from the combustion gas increases, and the torque of the radial inner end of the blade body trying to rotate toward the downstream side of the axis with the radial outer end of the blade body as the center increases. In this way, if the torque increases, it is necessary to increase the strength of the radially outer part around the trailing edge of the blade body. On the other hand, even if the torque increases, since the radially inner part of the blade body is the free end side of the fixed blade, there is no need to increase the strength of this part.

[0017] Therefore, in this method, the opening ratio of the second side region is reduced to suppress the amount of cooling air used, and on the other hand, the opening ratio of the first side region is increased to improve the cooling performance of the first side region, thereby suppressing the reduction in strength around the first side region. Therefore, in this method, the amount of cooling air used can be suppressed while effectively cooling the stationary blade to improve the durability of the stationary blade.

[0018] In a gas turbine of one mode involved in the invention for achieving the above-mentioned purpose, it comprises: a turbine rotor capable of rotating around an axis; a turbine casing covering the outer peripheral side of the turbine rotor; and a plurality of fixed blade rows arranged in the axial direction extending from the axis and mounted on the inner peripheral side of the turbine casing.

[0019] The plurality of fixed blade rows each have a plurality of fixed blades arranged in a circumferential direction relative to the axis. The plurality of fixed blades of the fixed blade row closest to the downstream side of the axis in the upstream and downstream sides of the axis in the axial direction of the plurality of fixed blade rows, i.e., the final-stage fixed blade row, are respectively fixed blades in the first embodiment. The plurality of fixed blades of the final-stage fixed blade row are respectively mounted on the turbine casing in the following manner: the blade height direction becomes the radial direction relative to the axis, the first side of the blade height becomes the radially outer side of the radially inner side and the radially outer side in the radial direction, and the side where the trailing edge exists relative to the leading edge becomes the downstream side of the axis.

[0020] Effects of the Invention

[0021] According to one aspect of the present invention, the stationary blades can be efficiently cooled by cooling air to improve the durability of the stationary blades, while the usage amount of the cooling air can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic cross-sectional view of a gas turbine in one embodiment according to the present invention.

[0023] Figure 2 This is a cross-sectional view of a main part of a gas turbine in one embodiment according to the present invention.

[0024] Figure 3 It is a cross-sectional view of a stationary blade in one embodiment according to the present invention.

[0025] Figure 4 is along Figure 3 Cross-sectional view taken along line IV-IV. DETAILED DESCRIPTION

[0026] Hereinafter, various embodiments and modifications of the present invention will be described in detail with reference to the drawings.

[0027] "Gas Turbine Implementation Methods"

[0028] refer to Figure 1 and Figure 2 An embodiment of a gas turbine will be described.

[0029] like Figure 1As shown, the gas turbine 1 in this embodiment includes: a compressor 10 that compresses external air A to generate compressed air Acom; a combustor 20 that burns fuel F from a fuel supply source in the compressed air Acom to generate combustion gas G; and a turbine 30 that is driven by the combustion gas G.

[0030] The compressor 10 has a compressor rotor 11 that rotates around the axis Ar, a compressor housing 15 that covers the compressor rotor 11, and a plurality of fixed blade rows 18. The turbine 30 has a turbine rotor 31 that rotates around the axis Ar, a turbine housing 35 that covers the turbine rotor 31, and a plurality of fixed blade rows 38. In addition, hereinafter, the direction in which the axis Ar extends is referred to as the axial direction Da, the circumferential direction centered on the axis Ar is referred to as the circumferential direction Dc, and the direction perpendicular to the axis Ar is referred to as the radial direction Dr. Furthermore, one side in the axial direction Da is referred to as the axial upstream side Dau, and the side opposite thereto is referred to as the axial downstream side Dad. Furthermore, in the radial direction Dr, the side close to the axis Ar is referred to as the radial inner side Dri, and the side opposite thereto is referred to as the radial outer side Dro.

[0031] The compressor 10 is arranged on the axial upstream side Dau with respect to the turbine 30 .

[0032] The compressor rotor 11 and the turbine rotor 31 are located on the same axis line Ar and are connected to each other to form a gas turbine rotor 2. For example, a rotor of a generator GEN is connected to the gas turbine rotor 2. The gas turbine 1 further includes an intermediate casing 6.

[0033] The intermediate housing 6 is disposed between the compressor housing 15 and the turbine housing 35 in the axial direction Da. The compressor housing 15, the intermediate housing 6, and the turbine housing 35 are connected to each other to form the gas turbine housing 5.

[0034] like Figure 1 and Figure 2 As shown, the compressor rotor 11 has a rotor shaft 12 extending along the axial direction Da with the axis Ar as the center, and a plurality of rotating blade rows 13 mounted on the rotor shaft 12. The plurality of rotating blade rows 13 are arranged in the axial direction Da. Each rotating blade row 13 is composed of a plurality of rotating blades arranged in the circumferential direction Dc. Any one of the plurality of fixed blade rows 18 is arranged on the axial downstream side Dad of each of the plurality of rotating blade rows 13. Each fixed blade row 18 is provided on the inner side of the compressor housing 15. Each fixed blade row 18 is composed of a plurality of fixed blades arranged in the circumferential direction Dc.

[0035] The turbine rotor 31 has a rotor shaft 32 extending along the axial direction Da with the axis Ar as the center, and a plurality of rotating blade rows 33 mounted on the rotor shaft 32. The plurality of rotating blade rows 33 are arranged in the axial direction Da. Each rotating blade row 33 is composed of a plurality of rotating blades arranged in the circumferential direction Dc. Any one of the plurality of fixed blade rows 38 is arranged on the axial upstream side Dau of each of the plurality of rotating blade rows 33. Each fixed blade row 38 is provided on the inner side of the turbine housing 35. Each fixed blade row 38 is composed of a plurality of fixed blades arranged in the circumferential direction Dc.

[0036] An annular space between the outer circumference of the rotor shaft 32 and the inner circumference of the turbine housing 35 in which the rotating blade row 33 and the stationary blade row 38 are arranged in the axial direction Da constitutes a combustion gas flow path 39 through which the combustion gas G from the combustor 20 flows.

[0037] like Figure 2 As shown, the turbine housing 35 includes a turbine housing body 36 and a plurality of split rings 37. The split ring 37 is located on the radially outer side Dro of the rotating blade row 33 and is opposed to the rotating blade row 33 in the radial direction Dr. The split ring 37 defines the edge of the radially outer side Dro of the combustion gas flow path 39 at the position in the axial direction Da where the rotating blade row 33 exists. The turbine housing body 36 is cylindrical with the axis Ar as the center in a manner surrounding the outer periphery of the turbine rotor 31. A plurality of fixed blade rows 38 and a plurality of split rings 37 are installed on the inner peripheral side of the turbine housing body 36.

[0038] The combustor 20 is mounted on the center casing 6 . The combustor 20 includes a tail pipe (or combustion pipe) 22 in which the fuel F is burned, and a plurality of combustion furnaces 21 that inject the fuel into the tail pipe 22 .

[0039] like Figure 1 As shown, the compressor 10 compresses the external air A to generate compressed air Acom. The compressed air Acom flows into the combustor 20. Fuel F is supplied to the combustor 20. The combustion furnace 21 of the combustor 20 injects the compressed air Acom and the fuel F into the tail cylinder 22. In the tail cylinder 22, the fuel F burns in the compressed air Acom to generate high-temperature and high-pressure combustion gas G. The combustion gas G is transported from the tail cylinder 22 to the combustion gas flow path 39 in the turbine 30. The combustion gas G rotates the turbine rotor 31 while flowing toward the downstream side Dad of the axis in the combustion gas flow path 39. The rotation of the turbine rotor 31 rotates the rotor of the generator GEN connected to the gas turbine rotor 2. As a result, the generator GEN generates electricity.

[0040] Hereinafter, the stationary blades constituting the stationary blade row 38 located closest to the axial downstream side Dad among the plurality of stationary blade rows 38 will be described.

[0041] "Stationary blade implementation"

[0042] Below, reference Figure 3 and Figure 4 , an implementation method of the fixed blade is described.

[0043] like Figure 3 As shown, the fixed blade 40 of the present embodiment has a blade body 41, an outer shroud 45o, an inner shroud 45i and a sealing device 49. The blade body 41 has a blade-shaped cross-sectional shape and extends along a blade height direction Dh having a directional component perpendicular to the cross-section. The outer shroud 45o is provided at one side of the blade height direction Dh in the blade body 41, that is, at the end of the first blade height side Dh1. The inner shroud 45i is provided at the other side of the blade height direction Dh in the blade body 41, that is, at the end of the second blade height side Dh2. The blade body 41, the inner shroud 45i and the outer shroud 45o are formed as a whole by casting or the like. The sealing device 49 is provided at the second blade height side Dh2 of the inner shroud 45i.

[0044] The fixed blade 40 is mounted on the turbine housing 35 (refer to Figure 2 ), the blade height direction Dh becomes the radial direction Dr. Also, one side in the blade height direction Dh, i.e., the blade height first side Dh1, becomes the radial outer side Dro, and the other side in the blade height direction Dh, i.e., the blade height second side Dh2, becomes the radial inner side Dri. Therefore, the inner shroud 45i is provided at the radial inner side Dri of the blade body 41, and the outer shroud 45i is provided at the radial inner side Dri of the blade body 41. o It is provided at the radially outer side Dro of the blade body 41. Therefore, in this embodiment, the blade height direction Dh is sometimes referred to as the radial direction Dr, the blade height first side Dh1 is referred to as the radially outer side Dro, and the blade height second side Dh2 is referred to as the radially inner side Dri.

[0045] The sealing device 49 seals between the stationary blades 40 and the rotor shaft 32 in the radial direction Dr. The outer shroud 45 o Together with the split ring 37, the inner shroud 45i defines a portion of the edge of the radially outer side Dro of the annular combustion gas flow path 39. Furthermore, the inner shroud 45i defines a portion of the edge of the radially inner side Dri of the annular combustion gas flow path 39.

[0046] The outer shroud 45o has an outer shroud body 46o and a hook 48o. The outer shroud body 46o is a plate-shaped member extending in a direction including a directional component in a direction perpendicular to the radial direction Dr, which is the blade height direction Dh. The outer shroud body 46o has an air path surface 47op and an anti-air path surface 47oo. op is a surface facing the radial inner side Dri as the second side Dh2 of the blade height, and the reverse air road surface 47oo is a surface facing the radial outer side Dro as the first side Dh1 of the blade height. The reverse air road surface 47oo and the air road surface 47op are in a back-to-back relationship. The hook portion 48o is provided on the reverse air road surface 47oo of the outer shroud body 46o. The hook portion 48o is configured to be mountable on the turbine housing body 36.

[0047] The inner shroud 45i has an inner shroud body 46i and a seal mounting portion 48i. The inner shroud body 46i is a plate-shaped member extending in a direction including a directional component in a direction perpendicular to the radial direction Dr which is the blade height direction Dh. The inner shroud body 46i has an air pavement surface 47ip and an anti-air pavement surface 47io. The air pavement surface 47ip is a surface facing the radial outer side Dro which is the first side Dh1 of the blade height and contacted by the combustion gas G. The anti-air pavement surface 47io is a surface facing the radial inner side Dri which is the second side Dh2 of the blade height. The anti-air pavement surface 47io and the air pavement surface 47ip are in a back-to-back relationship. The seal mounting portion 48i is provided on the anti-air pavement surface 47io of the inner shroud body 46i. The seal mounting portion 48i is configured to be able to hold the sealing device 49.

[0048] like Figure 4 As shown, the blade surface as the outer surface of the blade body 41 has a leading edge 42f, a trailing edge 42b, a negative pressure surface 43n as a convex surface, and a positive pressure surface 43p as a concave surface. The leading edge 42f and the trailing edge 42b exist at the connection portion between the negative pressure surface 43n and the positive pressure surface 43p. The leading edge 42f, the trailing edge 42b, the negative pressure surface 43n, and the positive pressure surface 43p all extend along the radial direction Dr as the blade height direction Dh. When the fixed blade 40 is mounted on the turbine housing 35, the leading edge 42f is located on the axial upstream side Dau relative to the trailing edge 42b.

[0049] The blade body 41 is disposed in the combustion gas flow path 39 through which the combustion gas G passes. The blade body 41 has a plurality of blade air passages 50 extending in the blade height direction Dh in the blade body 41 and a plurality of rear end air passages 55 arranged in the blade height direction Dh in the blade body 41.

[0050] The multiple blade air passages 50 formed in the blade body 41 are arranged along the arc line CL of the blade body 41. Here, the blade air passage 50 closest to the upstream side Dau of the axis among the multiple blade air passages 50 (in other words, the blade air passage 50 closest to the leading edge 42f side) is set as the front blade air passage 51, and the blade air passage 50 closest to the downstream side Dad of the axis is set as the rear blade air passage 52. The blade air passages 50 adjacent to each other in the multiple blade air passages 50 are connected to each other at one end portion on the first side Dh1 of the blade height and the second side Dh2 of the blade height, so that the multiple blade air passages 50 constitute a serpentine passage in which the passages undulate in the blade height direction Dh. The fixed blade 40 of the present embodiment has two blade air passages 50 as an even number. Therefore, in the present embodiment, the front blade air passage 51 and the rear blade air passage 52 are adjacent to each other.

[0051] The front blade air passage 51 has an inlet opening 51o that opens on the anti-air surface 47oo of the outer shroud 45o. The front blade air passage 51 extends from the inlet opening 51o toward the second side Dh2 of the blade height. A casing air passage 36p through which cooling air Acool can flow is formed on the turbine casing body 36. The cooling air Acool that flows out of the casing air passage 36p of the turbine casing body 36 flows into the front blade air passage 51 from the inlet opening 51o of the front blade air passage 51. In the process of flowing through the front blade air passage 51, the cooling air Acool performs convection cooling around the front blade air passage 51 in the blade body 41. The front blade air passage 51 and the rear blade air passage 52 are connected to each other at the ends of each other on the second side Dh2 of the blade height. Therefore, the cooling air Acool passing through the front blade air passage 51 flows into the rear blade air passage 52 from the end of the rear blade air passage 52 at the second blade height side Dh2, and flows toward the first blade height side Dh1 in the rear blade air passage 52. While flowing through the rear blade air passage 52, the cooling air Acool performs convection cooling around the rear blade air passage 52 in the blade body 41.

[0052] A plurality of rear end air passages 55 extend from the rear blade air passage 52 toward the rear edge 42b. The plurality of rear end air passages 55 have a rear edge opening 55o that opens on the rear edge 42b. The cooling air Acool flowing through the rear blade air passage 52 flows into the plurality of rear end air passages 55. While the cooling air Acool flows through the rear end air passage 55, convection cooling is performed around the rear end air passage 55 in the blade body 41. The cooling air Acool passing through the rear end air passage 55 is ejected from the rear edge opening 55o into the combustion gas flow path 39.

[0053] Here, the area within 25% of the length of the trailing edge 42b from the end of the first side Dh1 of the blade height of the trailing edge 42b to the second side Dh2 of the blade height in the blade height direction Dh of the trailing edge 42b is set as the first side area R1. The area within 25% of the length of the trailing edge 42b from the end of the second side Dh2 of the blade height of the trailing edge 42b to the first side Dh1 of the blade height in the blade height direction Dh of the trailing edge 42b is set as the second side area R2. Moreover, the area between the first side area R1 and the second side area R2 in the blade height direction Dh of the trailing edge 42b is set as the middle area RM. And, the opening area per unit length of the trailing edge opening 55o in the plurality of rear end air passages 55 in the blade height direction Dh of the trailing edge 42b is set as the opening ratio.

[0054] Regarding the opening ratio of the trailing edge opening 55o in the present embodiment, the first side region R1 is higher than the second side region R2. The opening areas of the trailing edge openings 55o of each of the plurality of rear end air passages 55 in the present embodiment are the same as each other. Therefore, in the present embodiment, regarding the number of trailing edge openings 55o, the first side region R1 is greater than the second side region R2. Specifically, the number of trailing edge openings 55o of the second side region R2 is 0, in other words, the opening ratio of the second side region R2 is 0. On the other hand, a plurality of trailing edge openings 55o are formed in the middle region RM and the first side region R1. The number of trailing edge openings 55o of the first side region R1 is more than three times the number of trailing edge openings 55o of the middle region RM, in other words, the opening ratio of the trailing edge openings 55o of the first side region R1 is more than three times the opening ratio of the trailing edge openings 55o of the middle region RM.

[0055] In recent years, in order to improve the performance of the gas turbine, a method of increasing the blade height of the blade body 41 (in other words, extending the length of the blade body 41 in the radial direction Dr) is being studied. If the length of the blade body 41 in the radial direction Dr is extended, the force received by the blade body 41 from the combustion gas G increases, and the torque of the end of the radial inner side Dri of the blade body 41 attempting to rotate toward the downstream side Dad of the axis with the end of the radial outer side Dro of the blade body 41 as the center increases. In this way, if the torque increases, it is necessary to increase the strength of the portion around the trailing edge 42b of the blade body 41 and on the radial outer side Dro. On the other hand, even if the torque increases, since the portion of the radial inner side Dri of the blade body 41 is the free end side of the fixed blade 40, there is no need to increase the strength of this portion.

[0056] Therefore, in the present embodiment, the opening ratio of the second side region R2 is reduced to suppress the use of the cooling air Acool, and on the other hand, the opening ratio of the first side region R1 is increased to improve the cooling performance of the first side region R1, thereby suppressing the reduction in strength around the first side region R1. Therefore, in the present embodiment, the use of the cooling air Acool can be suppressed while effectively cooling the fixed blade 40 to improve the durability of the fixed blade 40. In particular, in the present embodiment, the opening ratio of the second side region R2 is set to 0 to suppress the use of the cooling air Acool, and the opening ratio of the first side region R1 is set to more than three times the opening ratio of the middle region RM to improve the cooling performance of the first side region R1, so that the fixed blade 40 can be cooled extremely effectively.

[0057] Here, as a method of increasing the opening ratio, there are a method of increasing the opening area of ​​the trailing edge opening 55o and a method of increasing the number of the trailing edge openings 55o. As in the present embodiment, if the number of the plurality of trailing edge openings 55o in the first side region R1 is increased so that the pitch of the plurality of trailing edge openings 55o in the first side region R1 is narrowed, then the first side region R1 and the periphery can be cooled more uniformly than the method of increasing the opening area of ​​the trailing edge opening 55o.

[0058] As in the present embodiment, when the number of the plurality of blade air passages 50 is an even number, in the blade air passage 50 closest to the trailing edge 42b side, i.e., the rear blade air passage 52, the cooling air Acool flows toward the first side Dh1 of the blade height. Therefore, in the rear blade air passage 52, the temperature of the cooling air Acool flowing through the portion of the first side Dh1 of the blade height is higher than the temperature of the cooling air Acool flowing through the portion of the second side Dh2 of the blade height. When the first side region R1 is cooled with the high-temperature cooling air Acool, the opening ratio of the trailing edge opening 55o needs to be increased compared to the case where the first side region R1 is cooled with the low-temperature cooling air Acool. Therefore, from this point of view, when the plurality of blade air passages 50 is particularly an even number, the opening ratio of the trailing edge opening 55o in the plurality of rear end air passages 55 should be made higher in the first side region R1 than in the second side region R2.

[0059] "Modification of fixed blades"

[0060] The stationary blades 40 of the above embodiment are stationary blades 40 constituting the stationary blade row 38 closest to the axial downstream side Dad among the plurality of stationary blade rows 38. However, the stationary blades involved in the present invention may be stationary blades constituting stationary blade rows 38 other than the stationary blade row 38 closest to the axial downstream side Dad among the plurality of stationary blade rows 38. For example, the stationary blades involved in the present invention may be stationary blades constituting only one stationary blade row 38 closer to the axial upstream side Dad than the stationary blade row 38 closest to the axial downstream side Dad among the plurality of stationary blade rows 38.

[0061] The stationary blade 40 in the above embodiment has two blade air passages 50 which is an even number. However, the stationary blade according to the present invention may have three or more blade air passages 50. However, the number of blade air passages 50 is preferably an even number.

[0062] In the above embodiment, the aperture ratio of the second side region R2 is 0. However, if the aperture ratio of the first side region R1 is higher than that of the second side region R2, the aperture ratio of the second side region R2 may not be 0.

[0063] In the above embodiment, the number of the trailing edge openings 55o is increased to improve the opening ratio. However, in order to improve the opening ratio, the opening area of ​​the trailing edge openings 55o may be increased. However, when the opening ratio is increased, it is preferable to increase the number of the trailing edge openings 55o from the viewpoint of uniform cooling as described above.

[0064] In the above embodiment, the area within 25% of the length of the trailing edge 42b from the end of the first side Dh1 of the blade height of the trailing edge 42b to the second side Dh2 of the blade height in the blade height direction Dh of the trailing edge 42b is set as the first side area R1. In addition, in the above embodiment, the area within 25% of the length of the trailing edge 42b from the end of the second side Dh2 of the blade height of the trailing edge 42b to the first side Dh1 of the blade height in the blade height direction Dh of the trailing edge 42b is set as the second side area R2. However, the value of 25% can be appropriately changed within the range of 15% to 40% according to the temperature of the combustion gas G around the stationary blade 40 or the temperature of the cooling air Acool flowing into the stationary blade 40, and further according to the number of blade air passages 50 provided in the stationary blade 40 or the position of the stationary blade row 38 formed by the stationary blade 40. For example, an area within 30% of the length of the trailing edge 42b from the end of the first side Dh1 of the blade height of the trailing edge 42b to the second side Dh2 of the blade height in the blade height direction Dh of the trailing edge 42b may be set as the first side area R1, and an area within 20% of the length of the trailing edge 42b from the end of the second side Dh2 of the blade height of the trailing edge 42b to the first side Dh1 of the blade height in the blade height direction Dh of the trailing edge 42b may be set as the second side area R2.

[0065] The present invention is not limited to the above-described embodiments, and various additions, changes, substitutions, partial deletions, etc. may be made without departing from the conceptual idea and spirit of the present invention derived from the contents specified in the claims and their equivalents.

[0066] "P.S."

[0067] The stationary blades in the above-mentioned embodiment and modified examples can be understood, for example, as follows.

[0068] (1) The fixed blade in the first embodiment is a fixed blade 40 provided in a gas turbine, wherein the fixed blade 40 comprises: a blade body 41 having a blade-shaped cross-section and extending in a blade height direction Dh having a directional component perpendicular to the cross-section; an outer shroud 45o provided on the blade height first side Dh1 of the blade height first side Dh1 and the blade height second side Dh2 of the blade body 41 in the blade height direction Dh, and configured to be mountable on the turbine casing 35; a plurality of blade air passages 50 extending in the blade height direction Dh in the blade body 41; and a plurality of rear end air passages 55 arranged in the blade height direction Dh.

[0069] The blade body 41 has a leading edge 42f and a trailing edge 42b extending in the blade height direction Dh. The multiple blade air passages 50 are arranged from the leading edge 42f side toward the trailing edge 42b side. The blade air passage 50 closest to the leading edge 42f side among the multiple blade air passages 50, i.e., the front blade air passage 51, has an inlet opening 51o through which cooling air Acool can flow in at the end of the front blade air passage 51 on the first side Dh1 of the blade height. The blade air passages 50 adjacent to each other among the multiple blade air passages 50 are connected to each other at one of the ends on the first side Dh1 of the blade height and the ends on the second side Dh2 of the blade height, so that the multiple blade air passages 50 constitute a serpentine passage with undulating passages in the blade height direction Dh. The plurality of rear air passages 55 have a rear edge opening 55o, and the rear edge opening 55o extends from the blade air passage 50 closest to the rear edge 42b among the plurality of blade air passages 50, that is, the rear blade air passage 52, toward the rear edge 42b and opens on the rear edge 42b. A region including the end of the first blade height side Dh1 and excluding the end of the second blade height side Dh2 in the rear edge 42b extending in the blade height direction Dh is defined as a first side region R1. A region separating from the first side region R1 toward the second blade height side Dh2 in the rear edge 42b and including the end of the second blade height side Dh2 is defined as a second side region R2. The opening area per unit length of the rear edge opening 55o in the plurality of rear air passages 55 in the blade height direction Dh is defined as an opening ratio. At this time, regarding the opening ratio of the rear edge opening 55o in the plurality of rear air passages 55, the first side region R1 is higher than the second side region R2.

[0070] In recent years, in order to improve the performance of the gas turbine, a method of increasing the blade height of the blade body 41 (in other words, extending the length of the blade body 41 in the radial direction Dr) is being studied. If the length of the blade body 41 in the radial direction Dr is extended, the force received by the blade body 41 from the combustion gas G increases, and the torque of the end of the radial inner side Dri of the blade body 41 attempting to rotate toward the downstream side Dad of the axis with the end of the radial outer side Dro of the blade body 41 as the center increases. In this way, if the torque increases, it is necessary to increase the strength of the portion around the trailing edge 42b of the blade body 41 and on the radial outer side Dro. On the other hand, even if the torque increases, since the portion of the radial inner side Dri of the blade body 41 is the free end side of the fixed blade 40, there is no need to increase the strength of this portion.

[0071] Therefore, in this embodiment, the opening ratio of the second side region R2 is reduced to suppress the amount of cooling air Acool used, and on the other hand, the opening ratio of the first side region R1 is increased to improve the cooling performance of the first side region R1, thereby suppressing the reduction in strength around the first side region R1. Therefore, in this embodiment, the amount of cooling air Acool used can be suppressed while effectively cooling the stationary blade 40 to improve the durability of the stationary blade 40.

[0072] (2) Stationary blade in the second embodiment In the stationary blade 40 in the first embodiment,

[0073] Regarding the number of the plurality of trailing edge openings 55 o , the first side region R1 is greater than the second side region R2 .

[0074] As a method of increasing the opening ratio, there are a method of increasing the opening area of ​​the trailing edge opening 55o and a method of increasing the number of the trailing edge openings 55o. As in this embodiment, if the number of the plurality of trailing edge openings 55o in the first side region R1 is increased so that the pitch of the plurality of trailing edge openings 55o in the first side region R1 is narrowed, then the first side region R1 and the surrounding area can be cooled more uniformly than the method of increasing the opening area of ​​the trailing edge opening 55o.

[0075] (3) The stationary blade in the third embodiment In the stationary blade 40 in the first embodiment or the second embodiment,

[0076] In the trailing edge 42 b , the opening ratio of the middle region RM between the first side region R1 and the second side region R2 in the blade height direction Dh is higher than the opening ratio of the second side region R2 and lower than the opening ratio of the first side region R1 .

[0077] (4) A stationary blade in a fourth embodiment In the stationary blade 40 in the third embodiment,

[0078] The aperture ratio of the first side region R1 is three times or more higher than the aperture ratio of the middle region RM.

[0079] In this embodiment, the cooling performance around the first side region R1 in the blade body 41 can be improved.

[0080] (5) A stationary blade in a fifth aspect In the stationary blade 40 in any one of the first to fourth aspects,

[0081] The aperture ratio of the second side region R2 is 0.

[0082] In this aspect, the usage amount of the cooling air Acool can be suppressed.

[0083] (6) A stationary blade in a sixth aspect In the stationary blade 40 in any one of the first to fifth aspects,

[0084] The first side region R1 is a region within 25% of the length of the trailing edge 42b from the end of the first blade height side Dh1 of the trailing edge 42b to the second blade height side Dh2 in the blade height direction Dh of the trailing edge 42b. The second side region R2 is a region within 25% of the length of the trailing edge 42b from the end of the second blade height side Dh2 of the trailing edge 42b to the first blade height side Dh1 in the blade height direction Dh of the trailing edge 42b.

[0085] (7) A stationary blade in a seventh aspect In the stationary blade 40 in any one of the first to sixth aspects,

[0086] The number of the plurality of blade air passages 50 is an even number.

[0087] The cooling air Acool flowing into the front blade air passage 51 from the inlet opening 51o of the front blade air passage 51, which is the blade air passage 50 closest to the front edge 42f among the plurality of blade air passages 50, flows toward the second blade height side Dh2 in the front blade air passage 51. When the number of the plurality of blade air passages 50 is an even number, the cooling air Acool flows toward the first blade height side Dh1 in the blade air passage 50 closest to the rear edge 42b, which is the rear blade air passage 52. Therefore, in the rear blade air passage 52, the temperature of the cooling air Acool flowing through the first blade height side Dh1 is higher than the temperature of the cooling air Acool flowing through the second blade height side Dh2. When the first side region R1 is cooled by the high-temperature cooling air Acool, the opening ratio of the rear edge opening 55o needs to be increased compared to the case where the first side region R1 is cooled by the low-temperature cooling air Acool. Therefore, from this point of view, when the number of blade air passages 50 is particularly even, the opening ratio of the trailing edge openings 55 o in the rear end air passages 55 should be higher in the first side region R1 than in the second side region R2 .

[0088] (8) A stationary blade in an eighth aspect In the stationary blade 40 in any one of the first to sixth aspects,

[0089] The number of the plurality of blade air passages 50 is two.

[0090] The gas turbine in the above embodiment can be understood, for example, as follows.

[0091] (9) A gas turbine according to a ninth aspect comprises:

[0092] The turbine rotor 31 is rotatable about the axis Ar; the turbine housing 35 covers the outer circumference of the turbine rotor 31; and a plurality of fixed blade rows 38 are arranged in the axial direction Da extending from the axis Ar and mounted on the inner circumference of the turbine housing 35.

[0093] Each of the plurality of stationary blade rows 38 has a plurality of stationary blades 40 arranged in the circumferential direction Dc relative to the axis Ar. The plurality of stationary blade rows 38, that is, the stationary blade row 38 closest to the downstream side Dad in the axial direction Da in the axial upstream side Dau and the downstream side Dad in the axial direction Da, are the stationary blades 40 in any one of the first to eighth modes. The plurality of stationary blades 40 in the final stage stationary blade row 38 are respectively mounted on the turbine housing 35 in the following manner: the blade height direction Dh becomes the radial direction Dr relative to the axis Ar, the blade height first side Dh1 becomes the radial outer side Dro of the radial inner side Dri and the radial outer side Dro in the radial direction Dr, and the side where the trailing edge 42b exists relative to the leading edge 42f becomes the downstream side Dad in the axial direction.

[0094] Industrial Applicability

[0095] According to one aspect of the present invention, the stationary blades can be efficiently cooled by cooling air to improve the durability of the stationary blades, while the usage amount of the cooling air can be suppressed.

[0096] Explanation of symbols

[0097] 1-gas turbine, 2-gas turbine rotor, 5-gas turbine casing, 6-intermediate casing, 10-compressor, 11-compressor rotor, 12-rotor shaft, 13-rotating blade row, 15-compressor casing, 18-fixed blade row, 20-combustor, 21-combustion furnace, 22-tail tube (or combustion tube), 30-turbine, 31-turbine rotor, 32-rotor shaft, 33-rotating blade row, 35-turbine casing, 36-turbine casing body, 36p-casing air passage, 37-dividing ring, 38-fixed blade row, 39-combustion gas flow path, 40-fixed blade, 41-blade body, 42f-leading edge, 42b-trailing edge, 43n-negative pressure surface, 43p-positive pressure surface, 45o-outer shroud, 46o-outer shroud body, 47op-gas road surface, 47oo-reverse gas road surface, 48o-hook, 45 i-inner shroud, 46i-inner shroud body, 47ip-air pavement, 47io-anti-air pavement 48i-seal mounting portion, 49-sealing device, 50-blade air passage, 51-front blade air passage, 51o-inlet opening, 52-rear blade air passage, 55-rear end air passage, 55o-trailing edge opening, A-external air, Acom-compressed air, Acool-cooling air, G-combustion gas, F-fuel, CL-arc, Ar-axis, Da-axis direction, Dau-upstream side of the axis, Dad-downstream side of the axis, Dc-circumferential, Dr-radial, Dri-radial inside, Dro-radial outside, Dh-blade height direction, Dh1-first side of blade height, Dh2-second side of blade height, R1-first side area, R2-second side area, RM-middle area.

Claims

1. A stationary blade, which is a stationary blade provided in a gas turbine, the stationary blade comprising: A blade body having a blade-shaped cross section and extending in a blade height direction having a directional component perpendicular to the cross section; an outer shroud provided on the first side of the blade height of the blade body in the blade height direction and on the second side of the blade height, and configured to be mountable on the turbine housing; A plurality of blade air passages extending in the blade body along the height direction of the blade; and A plurality of rear air passages are arranged in the height direction of the blade, The blade body has a leading edge and a trailing edge extending in the blade height direction. The plurality of blade air passages are arranged from the leading edge side toward the trailing edge side, The front blade air passage, which is the blade air passage closest to the leading edge of the plurality of blade air passages, has an inlet opening through which cooling air can flow in at an end portion of the front blade air passage on the first side of the blade height. The blade air passages adjacent to each other in the plurality of blade air passages are connected to each other at one end at the end on the first side of the blade height and the end on the second side of the blade height, so that the plurality of blade air passages constitute a serpentine passage that undulates in the blade height direction. The plurality of rear end air passages have a trailing edge opening, the trailing edge opening extending from a blade air passage closest to the trailing edge among the plurality of blade air passages, i.e., a rear blade air passage, toward the trailing edge and opening at the trailing edge. In the case where a region including an end portion on a first side of the blade height and excluding an end portion on a second side of the blade height in the trailing edge extending in the blade height direction is set as a first side region, a region in the trailing edge separated from the first side region toward a second side of the blade height and including an end portion on the second side of the blade height is set as a second side region, and an opening area per unit length of the trailing edge opening in the plurality of rear end air passages in the blade height direction is set as an opening ratio, The opening ratio of the trailing edge openings in the plurality of rear end air passages is higher in the first side region than in the second side region.

2. The fixed blade according to claim 1, wherein: Regarding the number of the plurality of trailing edge openings, the first side area is greater than the second side area.

3. The fixed blade according to claim 1, wherein: In the trailing edge, the opening ratio of an intermediate region between the first side region and the second side region in the blade height direction is higher than the opening ratio of the second side region and lower than the opening ratio of the first side region.

4. The fixed blade according to claim 3, wherein: The opening ratio of the first side region is more than three times higher than the opening ratio of the middle region.

5. The stationary blade according to any one of claims 1 to 4, wherein: The opening ratio of the second side region is 0.

6. The stationary blade according to any one of claims 1 to 4, wherein: The first side region is a region within 25% of the length of the trailing edge in the blade height direction from the end of the trailing edge on the first side of the blade height to the second side of the blade height, The second side region is a region within 25% of a length of the trailing edge in the blade height direction from an end of the trailing edge on the blade height second side to the blade height first side.

7. The stationary blade according to any one of claims 1 to 4, wherein: The number of the plurality of blade air passages is an even number.

8. The stationary blade according to any one of claims 1 to 4, wherein: The number of the plurality of blade air passages is two.

9. A gas turbine comprising: The turbine rotor is capable of rotating about an axis; a turbine housing covering the outer circumference of the turbine rotor; and A plurality of fixed blade rows are arranged in the axial direction in which the axis extends and are mounted on the inner peripheral side of the turbine housing. Each of the plurality of stationary blade rows includes a plurality of stationary blades arranged in a circumferential direction relative to the axis. The plurality of fixed blades in the fixed blade row closest to the downstream side of the axis in the axial direction, i.e., the final fixed blade row, are the fixed blades according to any one of claims 1 to 4. The multiple fixed blades of the final stage fixed blade row are respectively installed on the turbine casing in the following manner: the blade height direction becomes the radial direction relative to the axis, the first side of the blade height becomes the radial outer side of the radial inner side and the radial outer side in the radial direction, and the side where the trailing edge exists relative to the leading edge becomes the downstream side of the axis.

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