Blade and gas turbine provided with same

Abstract

A cooling air passage of a rotor blade has: a main passage into which cooling air can flow; a plurality of front ejection holes capable of ejecting cooling air from the leading edge periphery in the blade surface; and a plurality of film holes that have blade surface discharge ports that open on the negative pressure surface of the blade main body, and that can discharge cooling air from the blade surface discharge ports along the blade surface. The main channel is provided with more than three odd number of blade inner channels extending in the blade body in the height direction of the blade. And the plurality of front ejection holes are communicated with the first blade inner channel which is closest to the front side in the odd number of blade inner channels. And the plurality of film holes are communicated with a second blade inner channel adjacent to the first blade inner channel in the odd number of blade inner channels. With the center position of the blade main body in the blade height direction as a reference, the aperture ratio, which is the area of the blade surface discharge ports per unit area on the hub side, is higher than the aperture ratio, which is the area of the blade surface discharge ports per unit area on the tip side.

Description

Technical Field

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

[0002] This application claims priority based on patent application No. 2022-096561 filed in Japan on June 15, 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 rotating about an axis, a turbine casing covering the rotor, and a plurality of rows of stationary blades. The turbine rotor comprises a rotor shaft centered about the axis and a plurality of rows of moving blades mounted on the rotor shaft. The plurality of rows of moving blades are arranged in the axial direction along which the axis extends. Each row of moving blades comprises a plurality of moving blades arranged in the circumferential direction relative to the axis. The plurality of rows of stationary blades are arranged in the axial direction and mounted on the inner circumference of the turbine casing. The plurality of rows of stationary blades are respectively arranged on the axial upstream side of any one of the plurality of rows of moving blades. Each row of stationary blades comprises a plurality of stationary blades arranged in the circumferential direction relative to the axis.

[0004] Generally, a moving blade has a blade body, a platform and a blade root. The blade body extends radially and has a blade shape in a cross section perpendicular to the radial direction relative to the axis. The platform is provided at one end radially inward of the blade body. The blade root is provided radially inward of the platform. The blade root is the part for mounting the moving blade on the rotor shaft.

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

[0006] For example, the moving blade described in the following patent document 1 has two cooling air channels through which cooling air can flow in the blade body of the stationary blade. Both cooling air channels have: a main channel having an inlet opening on the surface of the blade root and through which cooling air can flow; and a plurality of end holes capable of ejecting cooling air passing through the main channel from the end of the blade body to the outside. The main channel of each cooling air channel has: an inlet channel portion extending from the inlet of the blade root to the boundary between the platform and the blade body; and a blade body cooling channel portion having three blade inner channels extending radially in the blade body. The three blade inner channels are arranged along the arc of the blade body. The adjacent blade inner channels of the three blade inner channels are connected to each other at one end of one side of the radially inner end and the radially outer end, so that the blade body cooling channel portion constitutes a serpentine channel in which the channel undulates radially. The first cooling air channel of the two cooling air channels is arranged on the front side of the blade body, and the second cooling air channel is arranged on the rear side of the blade body. The frontmost blade passage among the three blade passages of the first cooling air passage is connected to a plurality of front ejection holes as the aforementioned plurality of end holes. The plurality of front ejection holes are opened in the blade surface at the leading edge surrounding portion including the leading edge. Furthermore, the rearmost blade passage among the three blade passages of the second cooling air passage is connected to a plurality of rear ejection holes as the aforementioned plurality of end holes. The plurality of rear ejection holes are opened at the trailing edge of the blade body.

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-001633 Summary of the invention

[0010] Technical issues to be solved by the invention

[0011] The rotor blades of a gas turbine that are exposed to high-temperature combustion gas are required to reduce the amount of cooling air used and to improve durability.

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

[0013] Means for solving technical problems

[0014] A rotor blade according to one aspect of the invention for achieving the above-mentioned object includes:

[0015] A blade body having a blade-shaped cross section and extending in a blade height direction including a directional component perpendicular to the cross section; a platform provided at one end of the blade body on the hub side of the blade tip side and the hub side in the blade height direction; a blade root provided on the hub side of the platform; and a cooling air passage formed throughout the blade root, the platform, and the blade body, through which cooling air can flow. The blade body has a blade surface facing a direction having a directional component perpendicular to the blade height direction and a blade tip surface facing the blade tip side in the blade height direction. The blade surface has a leading edge and a trailing edge extending in the blade height direction, and a positive pressure surface and a negative pressure surface extending from the leading edge to the trailing edge. The cooling air passage comprises: a main passage having an inlet opening on the surface of the blade root and through which cooling air can flow; a plurality of front ejection holes having a front ejection port opening in a portion of the blade surface including the leading edge and facing the leading edge relative to the trailing edge, i.e., the front side, and capable of ejecting cooling air passing through the main passage from the front ejection port; and a plurality of film holes having a blade surface ejection port opening on the blade surface of at least one of the positive pressure surface and the negative pressure surface, except for the leading edge side, and capable of ejecting cooling air passing through the main passage from the blade surface ejection port along the blade surface of at least one side. The main passage comprises an inlet passage portion and a blade body cooling passage portion, the inlet passage portion extending from the inlet to the boundary between the platform and the blade body, and the blade body cooling passage portion having three or more odd-numbered blade internal passages extending in the blade body along the blade height direction. The odd-numbered blade internal passages are arranged from the inlet passage portion to the front side along the arc of the blade body. The adjacent blade inner passages among the odd number of the blade inner passages are connected to each other at one end of one of the ends on the hub side and the ends on the blade tip side, so that the cooling passage portion of the blade body constitutes a serpentine passage in which the passage undulates along the blade height direction. The odd number of the blade inner passages among the multiple front ejection holes are connected to the first blade inner passage on the front side. The multiple membrane holes are connected to at least one of the first blade inner passage and the second blade inner passage adjacent to the first blade inner passage among the odd number of the blade inner passages. With the central position in the blade height direction in the blade body as a reference, the area of ​​the blade surface ejection outlet per unit area on the hub side, i.e., the opening ratio, is higher than the area of ​​the blade surface ejection outlet per unit area on the blade tip side, i.e., the opening ratio.

[0016] In this method, the cooling air flowing into the main channel from the inlet of the main channel in the cooling air channel flows into the blade body cooling channel portion of the main channel via the inlet channel portion of the main channel. While the cooling air flows in three or more odd-numbered blade internal channels in the blade body cooling channel portion, convection cooling is performed on the periphery of each blade internal channel. A portion of the cooling air flowing in three or more odd-numbered blade internal channels is ejected to the outside along the positive pressure surface or the negative pressure surface from a plurality of film holes. While the portion of the cooling air flows in the plurality of film holes, convection cooling is performed on the periphery of the film holes. Moreover, the cooling air ejected from the plurality of film holes performs film cooling on the positive pressure surface or the negative pressure surface. A portion of the cooling air flowing into the first blade internal channel which is the most forward side and located on the downstream side of the cooling air flow among the three or more odd-numbered blade internal channels is ejected to the outside from a plurality of front ejection holes. While the portion of the cooling air flows in the plurality of front ejection holes, convection cooling is performed on the periphery of the front ejection holes. Furthermore, the cooling air ejected from the plurality of front ejection holes suppresses the high-temperature combustion gas from directly colliding with the leading edge periphery, which is a part of the blade surface.

[0017] The interval between the positive pressure surface and the negative pressure surface, that is, the blade width, gradually increases from the tip side of the blade body toward the hub side. In addition, from the perspective of cooling the blade surface, the interval between the inner surface of the blade inner channel and the blade surface is an interval within a specified range. Under this relationship, the width of the multiple blade inner channels extending along the blade height direction also gradually increases from the tip side of the blade body toward the hub side. If the width of the blade inner channel gradually increases from the tip side of the blade body toward the hub side, the flow rate of the cooling air flowing in the blade inner channel is lower on the hub side than on the tip side. Therefore, the heat transfer rate between the cooling air flowing in the portion of the blade inner channel on the hub side and the blade body becomes lower than the heat transfer rate between the cooling air flowing in the portion of the blade inner channel on the tip side and the blade body. Therefore, the convection cooling effect generated by the cooling air flowing in the blade inner channel deteriorates on the hub side of the blade body.

[0018] Therefore, in this method, with the central position in the blade height direction in the blade body as a reference, the area of ​​the blade surface ejection outlet per unit area on the hub side, that is, the opening ratio, is made higher than the area of ​​the blade surface ejection outlet per unit area on the tip side, that is, the opening ratio, so as to improve the film cooling effect in the hub side portion, thereby improving the durability of the moving blade.

[0019] Furthermore, in the present embodiment, the cooling air flowing into the plurality of film holes is cooling air that flows from the rearmost blade inner passage among three or more odd blade inner passages to at least the downstream side portion of the second blade inner passage and has been heated to a certain degree. In addition, the downstream side here refers to the downstream side of the cooling air flow. Thus, in the present embodiment, the cooling air that is heated to a certain degree and has a poor convection cooling effect is used as film cooling air, so that the cold cooling air is not wasted, thereby effectively cooling the blade surface. Furthermore, in the present embodiment, the cooling air that flows into the plurality of front ejection holes is cooling air that flows from the rearmost blade inner passage among three or more odd blade inner passages to the first blade inner passage and has been heated to a considerable degree. In addition, the upstream side here refers to the upstream side of the cooling air flow. Thus, in the present embodiment, the cooling air that is heated to a considerable degree and has a poor convection cooling effect is used as cooling air for a portion of the blade surface, i.e., the front edge surrounding portion, so that the cold cooling air is not wasted, thereby effectively cooling the blade surface.

[0020] Therefore, in this aspect, the usage amount of cooling air can be suppressed and the durability of the moving blade can be improved.

[0021] In order to achieve the above-mentioned purpose, a gas turbine according to one embodiment of the invention comprises a plurality of moving blades according to the above-mentioned embodiment, and comprises: a rotor shaft which is rotatable about an axis and on which a plurality of the moving blades are arranged and installed in a circumferential direction relative to the axis; and a turbine casing which covers the plurality of moving blades and the outer peripheral side of the rotor shaft.

[0022] The moving blades are mounted on the rotor shaft in the following manner, that is, the blade height direction becomes the radial direction relative to the axis, the hub side becomes the radially outer side of the radially inner side and the radially outer side in the radial direction relative to the axis, and the front side becomes the upstream side of the axis in the axial direction in which the axis extends and the downstream side of the axis.

[0023] Effects of the Invention

[0024] According to one aspect of the present invention, it is possible to reduce the amount of cooling air used and improve the durability of the rotor blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic cross-sectional view of a gas turbine in one embodiment according to the present invention.

[0026] Figure 2 It is a perspective view of a moving blade in the first embodiment according to the present invention.

[0027] Figure 3It is a side view of the moving blade in the first embodiment according to the present invention (a side view of the moving blade as seen from the suction surface side).

[0028] Figure 4 It is a cross-sectional view of a moving blade in the first embodiment according to the present invention.

[0029] Figure 5 is along Figure 3 Sectional view taken along line VV in FIG.

[0030] Figure 6 is along Figure 3 Cross-sectional view taken along line VI-VI.

[0031] Figure 7 It is a side view of a moving blade in a second embodiment according to the present invention (a side view of the moving blade as viewed from the suction surface side).

[0032] Figure 8 is along Figure 7 Cross-sectional view taken along line VIII-VIII in FIG.

[0033] Fig. 9 It is a side view of a moving blade in a third embodiment according to the present invention (a side view of the moving blade as viewed from the positive pressure surface side).

[0034] Fig.10 is along Fig. 9 Sectional view taken along line XX. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of a moving blade and a gas turbine including the moving blade according to the present invention will be described in detail with reference to the drawings.

[0036] "Gas Turbine Implementation Methods"

[0037] refer to Figure 1 An embodiment of a gas turbine will be described.

[0038] like Figure 1 As shown, the gas turbine 10 of the present embodiment includes a compressor 20 for compressing air A, a combustor 30 for burning fuel F in the air A compressed by the compressor 20 to generate a combustion gas G, and a turbine 40 driven by the combustion gas G.

[0039] The compressor 20 has a compressor rotor 21 that rotates around the axis Ar, a compressor housing 25 that covers the compressor rotor 21, and a plurality of stationary blade rows 26. The turbine 40 has a turbine rotor 41 that rotates around the axis Ar, a turbine housing 45 that covers the turbine rotor 41, and a plurality of stationary blade rows 46. In addition, hereinafter, the direction in which the axis Ar extends is set as the axial direction Da, the circumferential direction centered on the axis Ar is simply set as the circumferential direction Dc, and the direction perpendicular to the axis Ar is set as the radial direction Dr. Furthermore, one side in the axial direction Da is set as the axial upstream side Dau, and the side opposite thereto is set as the axial downstream side Dad. Furthermore, in the radial direction Dr, the side close to the axis Ar is set as the radial inner side Dri, and the side opposite thereto is set as the radial outer side Dro.

[0040] The compressor 20 is arranged on the axial upstream side Dau with respect to the turbine 40 .

[0041] The compressor rotor 21 and the turbine rotor 41 are located on the same axis Ar and are connected to each other to form a gas turbine rotor 11. For example, a rotor of a generator GEN is connected to the gas turbine rotor 11. The gas turbine 10 further includes an intermediate casing 14. The intermediate casing 14 is arranged between the compressor casing 25 and the turbine casing 45 in the axial direction Da. The compressor casing 25, the intermediate casing 14, and the turbine casing 45 are connected to each other to form a gas turbine casing 15.

[0042] The compressor rotor 21 has a rotor shaft 22 extending along the axial direction Da with the axis Ar as the center, and a plurality of moving blade rows 23 mounted on the rotor shaft 22. The plurality of moving blade rows 23 are arranged along the axial direction Da. Each moving blade row 23 is composed of a plurality of moving blades arranged along the circumferential direction Dc. Any one of the plurality of stationary blade rows 26 is arranged on the axial downstream side Dad of each of the plurality of moving blade rows 23. Each stationary blade row 26 is provided on the inner side of the compressor housing 25. Each stationary blade row 26 is composed of a plurality of stationary blades arranged along the circumferential direction Dc.

[0043] The turbine rotor 41 has a rotor shaft 42 extending along the axial direction Da with the axis Ar as the center, and a plurality of moving blade rows 43 mounted on the rotor shaft 42. The plurality of moving blade rows 43 are arranged along the axial direction Da. Each moving blade row 43 is composed of a plurality of moving blades arranged along the circumferential direction Dc. Any one of the plurality of stationary blade rows 46 is arranged on the axial upstream side Dau of each of the plurality of moving blade rows 43. Each stationary blade row 46 is provided on the inner side of the turbine housing 45. Each stationary blade row 46 is composed of a plurality of stationary blades arranged along the circumferential direction Dc.

[0044] The combustor 30 is mounted on the center casing 14 .

[0045] The compressor 20 compresses air A to generate compressed air. The compressed air flows into the combustor 30. Fuel F is supplied to the combustor 30. In the combustor 30, the fuel F burns in the compressed air to generate high-temperature and high-pressure combustion gas G. The combustion gas G is delivered from the combustor 30 to the annular combustion gas flow path 49 in the turbine casing 45. The combustion gas G rotates the turbine rotor 41 while flowing toward the axial downstream side Dad in the combustion gas flow path 49. The rotation of the turbine rotor 41 rotates the rotor of the generator GEN connected to the gas turbine rotor 11. As a result, the generator GEN generates electricity.

[0046] Hereinafter, an embodiment and its modified examples related to the moving blades constituting the primary moving blade row 43 of the turbine 40 will be described.

[0047] "First embodiment of the moving blade"

[0048] refer to Figure 2 to Figure 6 , a first embodiment of the moving blade is described.

[0049] like Figure 2 and Figure 3 As shown, the rotor blade 50 in the present embodiment includes a blade body 51 , a platform 58 , a blade root 59 , a first cooling air passage 60 , and a second cooling air passage 80 .

[0050] The blade body 51 extends along the blade height direction Dh including a directional component perpendicular to the cross section, and the cross section is blade-shaped. The blade body 51 has a blade surface 52 facing a direction having a directional component perpendicular to the blade height direction Dh, and a blade tip surface 55 facing the blade tip side Dht on the blade height direction Dh and the blade tip side Dht on the hub side Dhh. The blade surface 52 has a leading edge 53f and a trailing edge 53b extending along the blade height direction Dh, and a positive pressure surface 54p and a negative pressure surface 54n extending from the leading edge 53f to the trailing edge 53b. The positive pressure surface 54p and the negative pressure surface 54n are in a back-to-back relationship with each other. The positive pressure surface 54p is a concave curved surface, and the negative pressure surface 54n is a convex curved surface.

[0051] If the moving blade 50 is mounted on the aforementioned rotor shaft 42, the blade height direction Dh becomes the radial direction Dr, the blade tip side Dht becomes the radial outer side Dro, and the hub side Dhh becomes the radial inner side Dri. Furthermore, the front side Df where the leading edge 53f exists relative to the trailing edge 53b becomes the axial upstream side Dau, and the rear side Db where the trailing edge 53b exists relative to the leading edge 53f becomes the axial downstream side Dad. Furthermore, the direction in which the positive pressure surface 54p and the negative pressure surface 54n are arranged becomes the circumferential direction Dc. Furthermore, if the moving blade 50 is mounted on the rotor shaft 42, the blade body 51 is located in the combustion gas flow path 49.

[0052] The platform 58 is provided on the hub side Dhh of the blade body 51. The platform 58 is a square plate-shaped member that expands in a direction including a directional component perpendicular to the blade height direction Dh, that is, the radial direction Dr.

[0053] The blade root 59 is provided on the hub side Dhh of the platform 58. The blade root 59 is a portion for attaching the moving blade 50 to the rotor shaft 42. The cross-sectional shape of the blade root 59 is a Christmas tree shape.

[0054] The first cooling air passage 60 and the second cooling air passage 80 are passages formed over the blade root 59, the platform 58, and the blade body 51 and through which the cooling air Ac can flow. The second cooling air passage 80 is arranged at a position further to the rear side Db than the first cooling air passage 60 in the rotor blade 50.

[0055] The first cooling air passage 60 has a main passage 61, a blade tip extraction hole 71, a plurality of front ejection holes 72, and a plurality of film holes 74. The main passage 61 opens on the bottom surface 59b of the blade root 59 and has an inlet 63 into which the cooling air Ac from the rotor shaft 42 can flow. In addition, the bottom surface 59b of the blade root 59 refers to a surface that is located closest to the hub side Dhh and faces the hub side Dhh among the surfaces of the blade root 59. The main passage 61 has an introduction passage portion 62 and a blade body cooling passage portion 65, the introduction passage portion 62 extending from the inlet 63 along the blade height direction Dh to the boundary between the platform 58 and the blade body 51, and the blade body cooling passage portion 65 having three blade in-passages 66 extending along the blade height direction Dh in the blade body 51.

[0056] The three blade inner passages 66 are arranged from the introduction passage portion 62 to the front side Df along the arc line CL of the blade body 51. Here, the blade inner passage 66 closest to the front side Df among the three blade inner passages 66 is set as the first blade inner passage 66a, the blade inner passage 66 adjacent to the first blade inner passage 66a is set as the second blade inner passage 66b, and the blade inner passage 66 closest to the rear side Db and adjacent to the second blade inner passage 66b is set as the third blade inner passage 66c. The third blade inner passage 66c extends from the introduction passage portion 62 along the blade height direction Dh.

[0057] The adjacent blade inner passages 66 among the three blade inner passages 66 are connected to each other at one end of one of the ends on the hub side Dhh and the ends on the blade tip side Dht, so that the blade body cooling passage portion 65 constitutes a serpentine passage in which the passage undulates along the blade height direction Dh. Specifically, one end on the blade tip side Dht of the third blade inner passage 66c is connected to one end on the blade tip side Dht of the second blade inner passage 66b, and one end on the hub side Dhh of the second blade inner passage 66b is connected to one end on the hub side Dhh of the first blade inner passage 66a.

[0058] The blade tip extraction hole 71 communicates with one end of the first blade intra-passage 66 a on the blade tip side Dht, and opens on the blade tip surface 55 .

[0059] The plurality of front ejection holes 72 each have a front ejection port 73 that opens in the portion of the blade surface 52 that includes the leading edge 53f and faces the front side Df, namely, the leading edge peripheral portion 56. The leading edge peripheral portion 56 is a portion of the blade surface 52 that combines the range from the leading edge 53f along the positive pressure surface 54p to the rear side Db to a predetermined distance and the range from the leading edge 53f along the negative pressure surface 54n to the rear side Db to a predetermined distance. Here, the predetermined distance refers to, for example, 1 / 20 of the distance from the leading edge 53f to the rear edge 53b along the positive pressure surface 54p (or the negative pressure surface 54n). The plurality of front ejection holes 72 are each connected to the first blade internal passage 66a, and extend from the first blade internal passage 66a in a predetermined direction and open in the leading edge peripheral portion 56 of the blade surface 52. Here, the predetermined direction refers to a direction in which the component in the direction parallel to the normal line of the blade surface 52 at the position of the front outlet 73 is larger than the component in the direction parallel to the tangent line of the blade surface 52 at the position of the front outlet 73 .

[0060] Each of the front ejection ports 73 of the plurality of front ejection holes 72 is formed from the hub side Dhh to the blade tip side Dht in the leading edge peripheral portion 56. However, with the central position in the blade height direction Dh in the leading edge peripheral portion 56 as a reference, the area of ​​the front ejection ports 73 per unit area in the portion on the blade tip side Dht, i.e., the opening ratio, is higher than the area of ​​the front ejection ports 73 per unit area in the portion on the hub side Dhh, i.e., the opening ratio. Specifically, in the present embodiment, with the central position in the blade height direction Dh in the leading edge peripheral portion 56 as a reference, the number of the front ejection ports 73 on the blade tip side Dht is greater than the number of the front ejection ports 73 on the hub side Dhh.

[0061] Each of the plurality of membrane holes 74 has a blade surface outlet 75 that opens on the blade surface 52 on at least one side of the positive pressure surface 54p and the negative pressure surface 54n, except for the leading edge surrounding portion 56. Each of the plurality of membrane holes 74 is connected to at least one of the three blade internal passages 66, and extends from the blade internal passage 66 in a predetermined direction and opens on the aforementioned at least one side of the blade surface 52. Here, the predetermined direction refers to a direction in which the component in the direction parallel to the tangent line of the blade surface 52 at the position of the blade surface outlet 75 is greater than the component in the direction parallel to the normal line of the blade surface 52 at the position of the blade surface outlet 75, and is directed toward the rear side Db. In addition, the plurality of membrane holes 74 in this embodiment are connected to the second blade internal passage 66b, and the blade surface outlet 75 thereof is opened only on the negative pressure surface 54n.

[0062] The area of ​​the blade surface outlets 75 per unit area, i.e., the opening ratio, in the portion on the hub side Dhh is higher than the area of ​​the blade surface outlets 75 per unit area, i.e., the opening ratio, in the portion on the tip side Dht, based on the central position in the blade height direction Dh on the blade surface 52 on at least one side described above. Specifically, in the present embodiment, the number of blade surface outlets 75 in the portion on the hub side Dhh is greater than the number of blade surface outlets 75 in the portion on the tip side Dht, based on the central position in the blade height direction Dh on the blade surface 52 on at least one side described above. More specifically, in the present embodiment, a plurality of blade surface outlets 75 are formed only in the portion on the hub side Dhh, and no blade surface outlets 75 are formed in the portion on the tip side Dht. In addition, as long as the number of blade surface outlets 75 is greater in the portion on the hub side Dhh than in the portion on the tip side Dht, based on the central position in the blade height direction Dh on the blade surface 52 on at least one side described above, the blade surface outlets 75 may be formed in the portion on the tip side Dht.

[0063] The second cooling air passage 80 has a main passage 81 and a plurality of rear ejection holes 88. The main passage 81 opens on the bottom surface 59b of the blade root 59 and has an inlet 83 into which the cooling air Ac from the rotor shaft 42 can flow. The inlet 83 of the main passage 81 in the second cooling air passage 80 is formed at a position further to the rear side Db than the inlet 63 of the main passage 61 in the first cooling air passage 60. The main passage 81 has an introduction passage portion 82 extending from the inlet 83 to the boundary between the platform 58 and the blade body 51 along the blade height direction Dh, and a blade body cooling passage portion 85 having three blade in-passages 86 extending along the blade height direction Dh in the blade body 51.

[0064] The three blade inner passages 86 are arranged from the introduction passage portion 82 to the rear side Db along the arc line CL of the blade body 51. Here, the blade inner passage 86 closest to the front side Df among the three blade inner passages 86 is set as the fourth blade inner passage 86a, the blade inner passage 86 adjacent to the fourth blade inner passage 86a is set as the fifth blade inner passage 86b, and the blade inner passage 86 closest to the rear side Db and adjacent to the fifth blade inner passage 86b is set as the sixth blade inner passage 86c. The fourth blade inner passage 86a extends from the introduction passage portion 82 along the blade height direction Dh.

[0065] The adjacent blade inner passages 86 among the three blade inner passages 86 are connected to each other at one end of one side of one end on the hub side Dhh and one end on the blade tip side Dht, so that the blade body cooling passage portion 85 forms a serpentine passage form in which the passage undulates along the blade height direction Dh. Specifically, one end on the blade tip side Dht of the fourth blade inner passage 86a is connected to one end on the blade tip side Dht of the fifth blade inner passage 86b, and one end on the hub side Dhh of the fifth blade inner passage 86b is connected to one end on the hub side Dhh of the sixth blade inner passage 86c.

[0066] The plurality of rear ejection holes 88 each have a rear ejection port 89 opened at the trailing edge 53b. The plurality of rear ejection holes 88 are arranged along the blade height direction Dh. The plurality of rear ejection holes 88 each communicate with the sixth blade inner passage 86c, in other words, the rearmost blade inner passage 86c, which is the rearmost blade inner passage 86c among the plurality of blade inner passages 86 in the second cooling air passage 80, and extend from the rearmost blade inner passage 86c to the trailing edge 53b.

[0067] In addition, the number of the blade intra-channels 86 in the second cooling air channel 80 of the present embodiment is three, but it may be two or more than four. Also, as in the present embodiment, when the number of the blade intra-channels 86 in the second cooling air channel 80 is an odd number, the second cooling air channel 80 may have a blade tip extraction hole that is connected to one end of the blade tip side Dht of the rearmost blade intra-channel 86c (the sixth blade intra-channel 86c) and opens on the blade tip surface 55. Furthermore, the second cooling air channel 80 may have a plurality of film holes that are connected to any one of the plurality of blade intra-channels 86 and open on the positive pressure surface 54p or the negative pressure surface 54n.

[0068] In the present embodiment, the cooling air Ac flowing into the main channel 61 from the inlet 63 of the main channel 61 in the first cooling air channel 60 flows into the blade body cooling channel portion 65 of the main channel 61 via the introduction channel portion 62 of the main channel 61. The cooling air Ac performs convection cooling on the periphery of each blade inner channel 66 while flowing in the three blade inner channels 66 in the blade body cooling channel portion 65. A portion of the cooling air Ac flowing in the three blade inner channels 66 is ejected to the outside along the positive pressure surface 54p or the negative pressure surface 54n from the plurality of film holes 74. A portion of the cooling air Ac performs convection cooling on the periphery of the film holes 74 while flowing in the plurality of film holes 74. Moreover, the cooling air Ac ejected from the plurality of film holes 74 performs film cooling on the positive pressure surface 54p or the negative pressure surface 54n. A portion of the cooling air Ac flowing into the first blade inner channel 66a located at the most front side Df of the three blade inner channels 66 and at the downstream side of the flow of the cooling air Ac is ejected to the outside from the plurality of front ejection holes 72. While a part of the cooling air Ac flows through the plurality of front ejection holes 72, it performs convection cooling on the periphery of the front ejection holes 72. Furthermore, the cooling air Ac ejected from the plurality of front ejection holes 72 suppresses the high-temperature combustion gas from directly colliding with the leading edge periphery 56, which is a part of the blade surface 52. Furthermore, the remaining part of the cooling air Ac that has flowed into the first blade internal passage 66a is ejected to the outside from the blade tip extraction hole 71.

[0069] In the present embodiment, the cooling air Ac flowing into the main passage 81 from the inlet 83 of the main passage 81 in the second cooling air passage 80 flows into the blade body cooling passage portion 85 of the main passage 81 via the introduction passage portion 82 of the main passage 81. The cooling air Ac performs convection cooling on the periphery of each blade body cooling passage 86 while flowing in the three blade inner passages 86 in the blade body cooling passage portion 85. A portion of the cooling air Ac flowing in the three blade inner passages 86 is ejected to the outside through the plurality of rear ejection holes 88 from the sixth blade inner passage (the rearmost blade inner passage) 86c located at the rearmost side Db of the three blade inner passages 86 and on the downstream side of the flow of the cooling air Ac. The cooling air Ac performs convection cooling on the periphery of the rear ejection holes 88 while flowing in the plurality of rear ejection holes 88. Moreover, the cooling air Ac ejected from the plurality of rear ejection holes 88 suppresses the generation of a wake of the combustion gas on the rear side Db of the trailing edge 53b.

[0070] The distance between the positive pressure surface 54p and the negative pressure surface 54n, that is, the blade width, gradually increases from the blade tip side Dht toward the hub side Dhh of the blade body 51. In addition, from the viewpoint of cooling the blade surface 52, the distance between the inner surface of the blade inner passage 66 and the blade surface 52 is within a predetermined range. Figure 5 and Figure 6As shown, the width of the plurality of blade inner passages 66 extending in the blade height direction Dh also gradually increases from the blade tip side Dht toward the hub side Dhh of the blade body 51. If the width of the blade inner passage 66 gradually increases from the blade tip side Dht toward the hub side Dhh of the blade body 51, the flow velocity of the cooling air Ac flowing in the blade inner passage 66 is lower on the hub side Dhh than on the blade tip side Dht. Therefore, the heat transfer rate between the cooling air Ac flowing in the portion of the blade inner passage 66 on the hub side Dhh and the blade body 51 becomes lower than the heat transfer rate between the cooling air Ac flowing in the portion of the blade inner passage 66 on the blade tip side Dht and the blade body 51. Therefore, the convection cooling effect generated by the cooling air Ac flowing in the blade inner passage 66 is deteriorated in the portion on the hub side Dhh of the blade body 51.

[0071] Therefore, in this embodiment, with the central position in the blade height direction Dh in the blade body 51 as a reference, the area of ​​the blade surface ejection outlet 75 per unit area on the hub side Dhh, that is, the opening ratio, is made higher than the area of ​​the blade surface ejection outlet 75 per unit area on the tip side Dht, that is, the opening ratio, so as to improve the film cooling effect in the part on the hub side Dhh, thereby improving the durability of the moving blade 50.

[0072] The blade body cooling passage portion 65 of the present embodiment has three blade inner passages 66, so the cooling air Ac flows from the hub side Dhh toward the blade tip side Dht in the first blade inner passage 66a at the most front side Df. Therefore, the cooling air Ac on the blade tip side Dht in the first blade inner passage 66a is heated more than the cooling air Ac on the hub side Dhh in the first blade inner passage 66a.

[0073] Therefore, in the present embodiment, the area of ​​the front ejection port 73 per unit area on the blade tip side Dht, i.e., the opening ratio, is made higher than the area of ​​the front ejection port 73 per unit area on the hub side Dhh, i.e., the opening ratio, based on the central position in the blade height direction Dh of the blade body 51. As a result, in the present embodiment, the flow rate of the cooling air Ac ejected from the front ejection port 73 on the blade tip side Dht becomes greater than the flow rate of the cooling air Ac ejected from the front ejection port 73 on the hub side Dhh, thereby improving the durability of the moving blade 50.

[0074] Furthermore, in the present embodiment, the cooling air Ac flowing into the plurality of film holes 74 is cooling air Ac flowing from the third blade inner passage 66c at the rearmost side Db of the three blade inner passages 66 to the downstream side portion of the second blade inner passage 66b and is already heated to a certain degree. In addition, the downstream side here refers to the downstream side of the flow of the cooling air Ac. In this way, in the present embodiment, the cooling air Ac that is heated to a certain degree and has a poor convection cooling effect is used as film cooling air, so that the cold cooling air Ac is not wasted, thereby effectively cooling the blade surface 52. Furthermore, in the present embodiment, the cooling air Ac flowing into the plurality of front ejection holes 72 is cooling air Ac flowing from the third blade inner passage 66c at the rearmost side Db of the three blade inner passages 66 to the first blade inner passage 66a and is already heated to a considerable degree. As described above, in the present embodiment, the cooling air Ac that has been heated to a considerable extent and has a poor convection cooling effect is used as cooling air for a portion of the blade surface 52 , namely, the leading edge peripheral portion 56 . Therefore, the cold cooling air Ac is not wasted, and the blade surface 52 can be effectively cooled.

[0075] The flow velocity of the combustion gas G flowing along the convex curved surface, that is, the negative pressure surface 54n, is higher than the flow velocity of the combustion gas G flowing along the concave curved surface, that is, the positive pressure surface 54p. Therefore, the heat transfer rate between the combustion gas G flowing along the negative pressure surface 54n and the negative pressure surface 54n is higher than the heat transfer rate between the combustion gas G flowing along the positive pressure surface 54p and the positive pressure surface 54p. That is, the negative pressure surface 54n is more easily heated by the combustion gas G than the positive pressure surface 54p.

[0076] Therefore, in this embodiment, the blade surface ejection port 75 is formed only on the negative pressure surface 54n, and the negative pressure surface 54n is film cooled to improve the durability of the moving blade 50. On the other hand, the blade surface ejection port 75 is not formed on the positive pressure surface 54p which is less likely to be heated by the combustion gas G than the negative pressure surface 54n, thereby suppressing the use of cooling air Ac.

[0077] Therefore, in the present embodiment, the usage amount of the cooling air Ac can be suppressed and the durability of the moving blade 50 can be improved.

[0078] "Second embodiment of the moving blade"

[0079] refer to Figure 7 and Figure 8 , a second embodiment of the moving blade is described.

[0080] Similar to the moving blade 50 in the first embodiment, the moving blade 50a in the present embodiment includes a blade body 51, a platform 58, a first cooling air passage 60a, and a second cooling air passage 80. The structure of the moving blade 50a in the present embodiment other than the structure of the first cooling air passage 60a is the same as the structure of the moving blade 50 in the first embodiment other than the structure of the first cooling air passage 60.

[0081] Similar to the first cooling air passage 60 in the first embodiment, the first cooling air passage 60a in this embodiment also has a main passage 61, a blade tip extraction hole 71, a plurality of front ejection holes 72, and a plurality of film holes 74a. The main passage 61 opens on the bottom surface 59b of the blade root 59, and has an inlet 63 into which the cooling air Ac from the rotor shaft 42 can flow. Similar to the main passage 61 of the first cooling air passage 60 in the first embodiment, the main passage 61 has an introduction passage portion 62 extending from the inlet 63 along the blade height direction Dh to the boundary between the platform 58 and the blade body 51, and a blade body cooling passage portion 65 having three blade in-blade passages 66 extending along the blade height direction Dh in the blade body 51. Similar to the blade body cooling passage portion 65 of the first cooling air passage 60 in the first embodiment, the adjacent blade inner passages 66 of the three blade inner passages 66 are connected to each other at one end of one of the ends on the hub side Dhh and the tip side Dht, so that the blade body cooling passage portion 65 forms a serpentine passage in which the passage undulates along the blade height direction Dh. Similar to the blade tip extraction hole 71 of the first cooling air passage 60 in the first embodiment, the blade tip extraction hole 71 is connected to one end on the blade tip side Dht of the first blade inner passage 66a and opens on the blade tip surface 55. Similar to the plurality of front ejection holes 72 of the first cooling air passage 60 in the first embodiment, the plurality of front ejection holes 72 each have a front ejection port 73 opened in the leading edge surrounding portion 56, which is a portion including the leading edge 53f and facing the front side Df in the blade surface 52, and are connected to the first blade inner passage 66a.

[0082] Similar to the plurality of membrane holes 74 in the first embodiment, the plurality of membrane holes 74a in the present embodiment also have blade surface ejection ports 75 that are open on the negative pressure surface 54n other than the leading edge surrounding portion 56 in the blade surface 52. In the present embodiment, the area of ​​the blade surface ejection ports 75 per unit area in the portion on the hub side Dhh, i.e., the opening rate, is higher than the area of ​​the blade surface ejection ports 75 per unit area in the portion on the blade tip side Dht, i.e., the opening rate, based on the central position in the blade height direction Dh on the negative pressure surface 54n. However, the plurality of membrane holes 74a in the present embodiment communicate with the first blade internal passage 66a on the most front side Df among the three blade internal passages 66.

[0083] Therefore, the cooling air Ac flowing into the plurality of film holes 74a is the cooling air Ac that has been heated to a considerable degree, flowing from the third blade inner passage 66c at the rearmost side Db among the three blade inner passages 66 via the second blade inner passage 66b to the upstream side portion of the first blade inner passage 66a. In this way, in the present embodiment, the cooling air Ac that has been heated to a considerable degree and has a poor convection cooling effect is used as film cooling air, so that the cold cooling air Ac is not wasted, and the blade surface 52 can be cooled more effectively than in the first embodiment.

[0084] “Third embodiment of the moving blade”

[0085] refer to Fig. 9 and Fig.10 , a third embodiment of the moving blade is described. Figure 3 and Figure 7 Likewise, Fig. 9 It is a side view of the moving blade, but it is not a side view of the moving blade viewed from the negative pressure side, but a side view of the moving blade viewed from the positive pressure side.

[0086] Similar to the moving blade 50 in the first embodiment, the moving blade 50b in the present embodiment includes a blade body 51, a platform 58, a first cooling air passage 60b, and a second cooling air passage 80. The structure of the moving blade 50b in the present embodiment other than the structure of the first cooling air passage 60b is the same as the structure of the moving blade 50 in the first embodiment other than the structure of the first cooling air passage 60.

[0087] Similar to the first cooling air passage 60 in the first embodiment, the first cooling air passage 60b in this embodiment also has a main passage 61, a blade tip extraction hole 71, a plurality of front ejection holes 72, and a plurality of film holes 74b. The main passage 61 opens on the bottom surface 59b of the blade root 59, and has an inlet 63 into which the cooling air Ac from the rotor shaft 42 can flow. Similar to the main passage 61 of the first cooling air passage 60 in the first embodiment, the main passage 61 has an introduction passage portion 62 extending from the inlet 63 along the blade height direction Dh to the boundary between the platform 58 and the blade body 51, and a blade body cooling passage portion 65 having three blade in-blade passages 66 extending along the blade height direction Dh in the blade body 51. Similar to the blade body cooling passage portion 65 of the first cooling air passage 60 in the first embodiment, the adjacent blade inner passages 66 of the three blade inner passages 66 are connected to each other at one end of one of the ends on the hub side Dhh and the tip side Dht, so that the blade body cooling passage portion 65 forms a serpentine passage in which the passage undulates along the blade height direction Dh. Similar to the blade tip extraction hole 71 of the first cooling air passage 60 in the first embodiment, the blade tip extraction hole 71 is connected to one end on the blade tip side Dht of the first blade inner passage 66a and opens on the blade tip surface 55. Similar to the plurality of front ejection holes 72 of the first cooling air passage 60 in the first embodiment, the plurality of front ejection holes 72 each have a front ejection port 73 opened in the leading edge surrounding portion 56, which is a portion including the leading edge 53f and facing the front side Df in the blade surface 52, and are connected to the first blade inner passage 66a.

[0088] The plurality of membrane holes 74b in the present embodiment include a plurality of negative pressure side membrane holes 74bn and a plurality of positive pressure side membrane holes 74bp. The plurality of negative pressure side membrane holes 74bn include a negative pressure surface outlet 75n as a blade surface outlet opening on the negative pressure surface 54n other than the leading edge surrounding portion 56 in the blade surface 52. In addition, the plurality of positive pressure side membrane holes 74bp include a positive pressure surface outlet 75p as a blade surface outlet opening on the positive pressure surface 54p other than the leading edge surrounding portion 56 in the blade surface 52. Similar to the membrane holes 74 in the first embodiment, the negative pressure side membrane holes 74bn are connected to the second blade internal passage 66b. On the other hand, the positive pressure side membrane holes 74bp are connected to the first blade internal passage 66a.

[0089] In the present embodiment, the area of ​​the negative pressure surface outlet 75n per unit area in the portion on the hub side Dhh, i.e., the opening ratio, is higher than the area of ​​the negative pressure surface outlet 75n per unit area in the portion on the tip side Dht, i.e., the opening ratio, based on the central position on the blade height direction Dh on the negative pressure surface 54n. Furthermore, the area of ​​the positive pressure surface outlet 75p per unit area in the portion on the hub side Dhh, i.e., the opening ratio, is higher than the area of ​​the positive pressure surface outlet 75p per unit area in the portion on the tip side Dht, i.e., the opening ratio, based on the central position on the blade height direction Dh on the positive pressure surface 54p. However, the number of the plurality of positive pressure side membrane holes 74bp is less than the number of the plurality of negative pressure side membrane holes 74bn.

[0090] In the present embodiment, film cooling can be performed not only on the negative pressure surface 54n but also on the positive pressure surface 54p. Thus, in the present embodiment, in terms of film cooling being performed not only on the negative pressure surface 54n but also on the positive pressure surface 54p, the amount of cooling air Ac used is increased compared to the above embodiments. Therefore, in the present embodiment, the number of positive pressure side film holes 74bp used for film cooling the positive pressure surface 54p, which is less likely to be heated by the combustion gas G than the negative pressure surface 54n, is less than the number of negative pressure side film holes 74bn. Moreover, in the present embodiment, the positive pressure side film holes 74bp are connected to the first blade inner passage 66a without wasting cold cooling air Ac, thereby effectively performing film cooling on the positive pressure surface 54p.

[0091] In addition, the present embodiment is a modified example of the first embodiment. However, in the second embodiment, similarly to the present embodiment, in addition to the plurality of negative-pressure-side membrane holes, a plurality of positive-pressure-side membrane holes may be provided.

[0092] "Other modification examples of moving blades"

[0093] In the above embodiments and modifications, the number of the jet ports in the hub side Dhh portion is made different from the number of the jet ports in the tip side Dht portion in order to make the opening ratio of the jet ports in the hub side Dhh portion different from the opening ratio of the jet ports in the tip side Dht portion. However, the opening ratio of the jet ports in the hub side Dhh portion may be made different from the opening ratio of the jet ports in the tip side Dht portion by making the opening area of ​​each jet port in the hub side Dhh portion different from the opening area of ​​each jet port in the tip side Dht portion.

[0094] Furthermore, each of the above embodiments targets the primary stage moving blades. However, the present invention may target moving blades other than the primary stage, for example, the second stage moving blades.

[0095] The present invention is not limited to the above-described embodiments and modifications, and various additions, changes, substitutions, and partial deletions may be made without departing from the conceptual idea and spirit of the present invention derived from the contents defined in the claims and their equivalents.

[0096] "P.S."

[0097] The moving blades in the above-mentioned embodiment and modified examples can be understood, for example, as follows.

[0098] (1) The moving blade in the first aspect includes:

[0099] The blade body 51 has a blade-shaped cross section and extends along a blade height direction Dh including a directional component perpendicular to the cross section; a platform 58 is provided at one end of the blade body 51 on the hub side Dhh of the blade tip side Dht and the hub side Dhh in the blade height direction Dh; a blade root 59 is provided on the hub side Dhh of the platform 58; and cooling air passages 60, 60a, 60b are formed over the blade root 59, the platform 58, and the blade body 51, and cooling air Ac can flow. The blade body 51 has a blade surface 52 facing a direction having a directional component perpendicular to the blade height direction Dh and a blade tip surface 55 facing the blade tip side Dht in the blade height direction Dh. The blade surface 52 has a leading edge 53f and a trailing edge 53b extending in the blade height direction Dh, and a positive pressure surface 54p and a negative pressure surface 54n extending from the leading edge 53f to the trailing edge 53b. The cooling air passage 60, 60a, 60b comprises: a main passage 61 having an inlet 63 opened on the surface of the blade root 59 and through which cooling air Ac can flow; a plurality of front ejection holes 72 having a front ejection port 73 opened in a portion of the blade surface 52 including the leading edge 53f and facing the leading edge 53f relative to the trailing edge 53b, namely, a front edge peripheral portion 56, and capable of ejecting cooling air Ac passing through the main passage 61 from the front ejection port 73; and a plurality of film holes 74, 74a, 74b having blade surface ejection ports 75, 75n, 75p opened on the blade surface 52 on at least one side of the positive pressure surface 54p and the negative pressure surface 54n except for the leading edge peripheral portion 56, and capable of ejecting cooling air Ac passing through the main passage 61 from the blade surface ejection ports 75, 75n, 75p along the blade surface 52 on at least one side. The main passage 61 includes an introduction passage portion 62 and a blade body cooling passage portion 65. The introduction passage portion 62 extends from the inlet 63 to the boundary between the platform 58 and the blade body 51. The blade body cooling passage portion 65 includes three or more odd-numbered blade inner passages 66 extending in the blade body 51 along the blade height direction Dh. The odd-numbered blade inner passages 66 are arranged along the arc line CL of the blade body 51 from the introduction passage portion 62 toward the front side Df. The blade inner passages 66 adjacent to each other among the odd-numbered blade inner passages 66 are connected to each other at one end of one end of the hub side Dhh and one end of the blade tip side Dht, so that the blade body cooling passage portion 65 forms a serpentine passage in which the passage undulates along the blade height direction Dh. The plurality of front ejection holes 72 are connected to the first blade inner passage 66a closest to the front side Df among the odd-numbered blade inner passages 66.The plurality of film holes 74, 74a, 74b are connected to at least one of the first blade inner passage 66a and the second blade inner passage 66b adjacent to the first blade inner passage 66a among the odd number of the blade inner passages 66. With the central position in the blade height direction Dh of the blade body 51 as a reference, the area of ​​the blade surface ejection outlet 75, 75n, 75p per unit area on the hub side Dhh, i.e., the opening ratio, is higher than the area of ​​the blade surface ejection outlet 75, 75n, 75p per unit area on the blade tip side Dht.

[0100] In this embodiment, the cooling air Ac flowing into the main channel 61 from the inlet 63 of the main channel 61 in the cooling air channel 60, 60a, 60b flows into the blade body cooling channel portion 65 of the main channel 61 via the introduction channel portion 62 of the main channel 61. The cooling air Ac performs convection cooling on the periphery of each blade inner channel 66 while flowing in three or more odd-numbered inner blade channels 66 in the blade body cooling channel portion 65.

[0101] A portion of the cooling air Ac flowing in more than three odd-numbered blade internal passages 66 is ejected to the outside from a plurality of film holes 74, 74a, 74b along the positive pressure surface 54p or the negative pressure surface 54n. While a portion of the cooling air Ac flows in the plurality of film holes 74, 74a, 74b, convection cooling is performed on the periphery of the film holes 74, 74a, 74b. Moreover, the cooling air Ac ejected from the plurality of film holes 74, 74a, 74b performs film cooling on the positive pressure surface 54p or the negative pressure surface 54n. A portion of the cooling air Ac flowing into the first blade internal passage 66a, which is located at the most front side Df among the more than three odd-numbered blade internal passages 66 and is located at the downstream side of the flow of the cooling air Ac, is ejected to the outside from a plurality of front ejection holes 72. While a portion of the cooling air Ac flows in the plurality of front ejection holes 72, convection cooling is performed on the periphery of the front ejection holes 72. Furthermore, the cooling air Ac ejected from the plurality of front ejection holes 72 suppresses the high-temperature combustion gas G from directly colliding with the leading edge surrounding portion 56 which is a part of the blade surface 52 .

[0102] The interval between the positive pressure surface 54p and the negative pressure surface 54n, that is, the blade width, gradually increases from the tip side Dht of the blade body 51 toward the hub side Dhh. In addition, from the perspective of cooling the blade surface 52, the interval between the inner surface of the blade inner channel 66 and the blade surface 52 is an interval within a predetermined range. Under this relationship, the width of the multiple blade inner channels 66 extending along the blade height direction Dh also gradually increases from the tip side Dht of the blade body 51 toward the hub side Dhh. If the width of the blade inner channel 66 gradually increases from the tip side Dht of the blade body 51 toward the hub side Dhh, the flow rate of the cooling air Ac flowing in the blade inner channel 66 is lower on the hub side Dhh than on the tip side Dht. Therefore, the heat transfer rate between the cooling air Ac flowing in the portion on the hub side Dhh of the inner blade passage 66 and the blade body 51 becomes lower than the heat transfer rate between the cooling air Ac flowing in the portion on the tip side Dht of the inner blade passage 66 and the blade body 51. Therefore, the convection cooling effect generated by the cooling air Ac flowing in the inner blade passage 66 is deteriorated in the portion on the hub side Dhh of the blade body 51.

[0103] Therefore, in this method, with the central position in the blade height direction Dh in the blade body 51 as a reference, the area of ​​the blade surface ejection outlets 75, 75n, 75p per unit area on the hub side Dhh, that is, the opening ratio, is made higher than the area of ​​the blade surface ejection outlets 75, 75n, 75p per unit area on the tip side Dht, that is, the opening ratio, so as to improve the film cooling effect in the portion on the hub side Dhh, thereby improving the durability of the moving blade 50.

[0104] Furthermore, in the present embodiment, the cooling air Ac flowing into the plurality of film holes 74, 74a, 74b is cooling air Ac flowing from the inner blade passage 66 at the rearmost side Db among the three or more odd-numbered inner blade passages 66 to at least the downstream side of the second inner blade passage 66b and is heated to a certain degree. In addition, the downstream side here refers to the downstream side of the flow of the cooling air Ac. In this way, in the present embodiment, the cooling air Ac that is heated to a certain degree and has a poor convection cooling effect is used as film cooling air, so that the cold cooling air Ac is not wasted, thereby effectively cooling the blade surface 52. Furthermore, in the present embodiment, the cooling air Ac flowing into the plurality of front ejection holes 72 is cooling air Ac flowing from the inner blade passage 66 at the rearmost side Db among the three or more odd-numbered inner blade passages 66 to the first inner blade passage 66a and is heated to a considerable degree. In addition, the upstream side here refers to the upstream side of the flow of the cooling air Ac. Thus, in this embodiment, the cooling air Ac that has been heated to a considerable degree and has a poor convection cooling effect is used as cooling air for a portion of the blade surface 52, namely, the leading edge peripheral portion 56. Therefore, the cold cooling air Ac is not wasted, and the blade surface 52 can be effectively cooled.

[0105] Therefore, in this embodiment, the usage amount of the cooling air Ac can be suppressed and the durability of the moving blade can be improved.

[0106] (2) Moving Blades in Second Embodiment In the moving blades in the first embodiment, with the center position of the blade body 51 in the blade height direction Dh as a reference, the number of the blade surface ejection ports 75, 75n, 75p is greater on the hub side Dhh than on the tip side Dht.

[0107] (3) The moving blade in the third embodiment In the moving blade in the first embodiment, the blade surface ejection ports 75, 75n, 75p exist only on the hub side Dhh and do not exist on the blade tip side Dht, based on the central position of the blade body 51 in the blade height direction Dh.

[0108] (4) Moving Blade in Fourth Mode In the moving blade in any one of the first to third modes, the plurality of film holes 74 a communicate with only the first intra-blade passages 66 a among an odd number of the intra-blade passages 66 .

[0109] In this embodiment, the cooling air Ac flowing into the plurality of film holes 74a is the cooling air Ac that has been heated to a considerable degree from the blade inner passage 66 at the rearmost side Db among the three or more odd-numbered blade inner passages 66 through the second blade inner passage 66b to the upstream side of the first blade inner passage 66a. In this way, in this embodiment, the cooling air Ac that has been heated to a considerable degree and has a poor convection cooling effect is used as film cooling air, so that the cold cooling air Ac is not wasted, and the blade surface 52 can be effectively cooled.

[0110] (5) Moving Blade in Fifth Aspect In the moving blade in any one of the first to fourth aspects, the blade surface discharge port 75 is formed only in the suction surface 54n.

[0111] The flow velocity of the combustion gas G flowing along the convex curved surface, that is, the negative pressure surface 54n, is higher than the flow velocity of the combustion gas G flowing along the concave curved surface, that is, the positive pressure surface 54p. Therefore, the heat transfer rate between the combustion gas G flowing along the negative pressure surface 54n and the negative pressure surface 54n is higher than the heat transfer rate between the combustion gas G flowing along the positive pressure surface 54p and the positive pressure surface 54p. That is, the negative pressure surface 54n is more easily heated by the combustion gas G than the positive pressure surface 54p.

[0112] Therefore, in the present method, the blade surface ejection port 75 is formed only on the negative pressure surface 54n, and the negative pressure surface 54n is subjected to film cooling to improve the durability of the moving blade 50. On the other hand, the blade surface ejection port is not formed on the positive pressure surface 54p which is less likely to be heated by the combustion gas G than the negative pressure surface 54n, thereby suppressing the use of cooling air Ac.

[0113] (6) In the movable blade in the sixth embodiment, in the movable blade in any one of the first embodiment to the fifth embodiment, with the central position in the blade height direction Dh in the blade body 51 as a reference, the area of ​​the front ejection outlet 73 per unit area on the tip side Dht, that is, the opening ratio, is higher than the area of ​​the front ejection outlet 73 per unit area on the hub side Dhh.

[0114] The blade body cooling passage portion 65 of this embodiment has an odd number of blade inner passages 66 of more than three, so the cooling air Ac flows from the hub side Dhh toward the blade tip side Dht in the first blade inner passage 66a on the most front side Df. Therefore, the cooling air Ac on the blade tip side Dht in the first blade inner passage 66a is heated more than the cooling air Ac on the hub side Dhh in the first blade inner passage 66a.

[0115] Therefore, in this embodiment, the area of ​​the front outlet 73 per unit area on the blade tip side Dht, i.e., the opening ratio, is made higher than the area of ​​the front outlet 73 per unit area on the hub side Dhh, i.e., the opening ratio, based on the central position in the blade height direction Dh of the blade body 51. As a result, in this embodiment, the flow rate of the cooling air Ac ejected from the front outlet 73 on the blade tip side Dht becomes larger than the flow rate of the cooling air Ac ejected from the front outlet 73 on the hub side Dhh, thereby improving the durability of the moving blade 50.

[0116] (7) In the moving blade in any one of the first to sixth modes, the cooling air passage 60, 60a, 60b has a tip extraction hole 71 which is connected to one end of the tip side Dht of the first blade inner passage 66a and can eject the cooling air Ac passing through the first blade inner passage 66a from the tip surface 55.

[0117] The blade body cooling channel portion 65 of this embodiment has an odd number of blade inner channels 66 of more than three, so the cooling air Ac flows from the hub side Dhh toward the blade tip side Dht in the first blade inner channel 66a on the front side Df. If there is no blade tip extraction hole 71, the flow of cooling air Ac is blocked in the portion on the blade tip side Dht in the first blade inner channel 66a, and the convection cooling effect in the portion on the blade tip side Dht is reduced. Therefore, in this embodiment, by providing the blade tip extraction hole 71, the flow of cooling air Ac in the portion on the blade tip side Dht in the first blade inner channel 66a is ensured, and the reduction of the convection cooling effect in the portion on the blade tip side Dht is suppressed.

[0118] (8) The moving blade in the eighth embodiment is a moving blade in any one of the first to seventh embodiments, and in addition to the cooling air passages 60, 60a, 60b, i.e., the first cooling air passages 60, 60a, 60b, further comprises a second cooling air passage 80 formed throughout the blade root 59, the platform 58 and the blade body 51 and through which the cooling air Ac can flow.

[0119] The second cooling air passage 80 includes: a main passage 81, which is arranged on the side of the trailing edge 53b relative to the leading edge 53f with reference to the first cooling air passage 60, 60a, 60b, and has an inlet 83 opened on the surface of the blade root 59 and through which cooling air Ac can flow; and a plurality of rear ejection holes 88, which have rear ejection outlets 89 capable of ejecting the cooling air Ac passing through the main passage 81 from the trailing edge 53b to the outside. The main passage 81 in the second cooling air passage 80 includes an introduction passage portion 82 extending from the inlet 83 in the second cooling air passage 80 to the boundary between the platform 58 and the blade body 51, and a blade body cooling passage portion 85 including a plurality of blade in-passages 86 extending in the blade body 51 along the blade height direction Dh. The plurality of blade in-channels 86 in the second cooling air channel 80 are arranged along the arc line CL of the blade body 51 from the inlet channel portion 82 in the second cooling air channel 80 toward the rear side Db. Adjacent blade in-channels 86 in the plurality of blade in-channels 86 in the second cooling air channel 80 are connected to each other at one end of one end on the hub side Dhh and one end on the blade tip side Dht, so that the blade body cooling channel portion 85 in the second cooling air channel 80 forms a serpentine channel in which the channel undulates along the blade height direction Dh. The plurality of rear ejection holes 88 are connected to the rearmost blade in-channel 86c in the plurality of blade in-channels 86 in the second cooling air channel 80, which is closest to the rear side Db.

[0120] In this embodiment, the cooling air Ac is convectively cooled around each blade inner passage 86 while flowing through the plurality of blade inner passages 86 of the second cooling air passage 80. A portion of the cooling air Ac flowing through the rearmost blade inner passage 86c at the rearmost side Db among the plurality of blade inner passages 86 is ejected to the outside from the plurality of rear ejection holes 88. A portion of the cooling air Ac is convectively cooled around the rear ejection holes 88 while flowing through the plurality of rear ejection holes 88. Furthermore, the cooling air Ac ejected from the plurality of rear ejection holes 88 suppresses the generation of a wake of the combustion gas G at the rear side Db of the trailing edge 53b.

[0121] The gas turbine in the above-mentioned embodiment and modified examples can be understood, for example, as follows.

[0122] (9) The gas turbine in the ninth aspect comprises a plurality of moving blades according to any one of the first to eighth aspects, and comprises: a rotor shaft 42 which is rotatable about an axis Ar and on which the plurality of moving blades are arranged and mounted along a circumferential direction Dc relative to the axis Ar; and a turbine casing 45 which covers the plurality of moving blades and the outer peripheral side of the rotor shaft 42.

[0123] The moving blades are mounted on the rotor shaft 42 in the following manner, that is, the blade height direction Dh becomes the radial direction Dr relative to the axis Ar, the hub side Dhh becomes the radial inner side Dri and the radial outer side Dro on the radial direction Dr relative to the axis Ar, and the front side Df becomes the axial upstream side Dau and the axial downstream side Dad in the axial direction Da in which the axis Ar extends.

[0124] Industrial Applicability

[0125] According to one aspect of the present invention, it is possible to reduce the amount of cooling air used and improve the durability of the rotor blade.

[0126] Explanation of symbols

[0127] 10-gas turbine, 11-gas turbine rotor, 14-intermediate casing, 15-gas turbine casing, 20-compressor, 21-compressor rotor, 22-rotor shaft, 23-moving blade row, 25-compressor casing, 26-stationary blade row, 30-combustor, 40-turbine, 41-turbine rotor, 42-rotor shaft, 43-moving blade row, 45-turbine casing, 49-combustion gas flow path, 50, 50a, 50b-moving blade, 51-blade body, 52-blade surface, 53f-leading edge, 54-blade body, 55-blade surface, 56-blade surface, 57-blade surface, 58-blade surface, 59-blade surface, 60-blade surface, 61-blade surface, 62-blade surface, 63-blade surface, 64-blade surface, 65-blade surface, 66-blade surface, 67-blade surface, 68-blade surface, 69-blade surface, 70-blade surface, 71-blade surface, 72-blade surface, 73-blade surface, 74-blade surface, 75-blade surface, 76-blade surface, 77-blade surface, 78-blade surface, 79-blade surface, 80-blade surface, 81-blade surface, 82-blade surface, 83-blade surface, 84-blade surface, 85-blade surface, 86-blade surface, 87-blade surface, 88-blade surface, 89-blade surface, 90-blade surface, 91-blade surface, 92-blade surface, 93-blade surface, 9 3b-trailing edge, 54n-negative pressure surface, 54p-positive pressure surface, 55-blade tip surface, 56-leading edge peripheral portion, 58-platform, 59-blade root, 59b-bottom surface, 60, 60a, 60b-first cooling air channel (or simply referred to as cooling air channel), 61-main channel, 62-introduction channel portion, 63-inlet, 65-blade main body cooling channel portion, 66-blade inner channel, 66a-first blade inner channel, 66b-second blade inner channel, 66c-third blade inner channel, 71-blade tip extraction outlet hole, 72-front outlet hole, 73-front outlet, 74, 74a, 74b-membrane hole, 74bn-negative pressure side membrane hole, 74bp-positive pressure side membrane hole, 75-blade surface outlet, 75n-negative pressure surface outlet (blade surface outlet), 75p-positive pressure surface outlet (blade surface outlet), 80-second cooling air channel, 81-main channel, 82-introduction channel part, 83-inlet, 85-blade body cooling channel part, 86-blade inner channel, 86a-fourth blade inner channel, 86b-fifth blade Intra-blade channel, 86c-the sixth blade intra-channel (the last blade intra-channel), 88-rear ejection hole, 89-rear ejection port, A-air, Ac-cooling air, F-fuel, G-combustion gas, Ar-axis, CL-arc line, Da-axis direction, Dau-upstream side of the axis, Dad-downstream side of the axis, Dc-circumferential direction, Dr-radial direction, Dri-radial inner side, Dro-radial outer side, Dh-blade height direction, Dhh-hub side, Dht-tip side, Df-front side, Db-rear side.

Claims

1. A moving blade, comprising: A blade body having a blade-shaped cross section and extending in a blade height direction including a directional component perpendicular to the cross section; A platform is provided at one end of the blade body on the hub side of the blade tip side and the hub side in the height direction of the blade; a blade root, disposed on the hub side of the platform; and A cooling air passage is formed throughout the blade root, the platform and the blade body, and cooling air can flow through it. The blade body has a blade surface facing a direction having a directional component perpendicular to the blade height direction and a blade tip surface facing the blade tip side in the blade height direction. The blade surface has a leading edge and a trailing edge extending in the height direction of the blade, and a positive pressure surface and a negative pressure surface extending from the leading edge to the trailing edge. The cooling air passage has: a main passage having an inlet opening on the surface of the blade root and into which cooling air can flow; a plurality of front ejection holes, including a front ejection port opening in a portion of the blade surface that includes the leading edge and faces the leading edge relative to the trailing edge, i.e., a front side, i.e., a leading edge peripheral portion, and capable of ejecting cooling air passing through the main passage from the front ejection port; and A plurality of film holes have blade surface ejection ports opening on the blade surface except for the leading edge surrounding portion and on at least one of the positive pressure surface and the negative pressure surface, and are capable of ejecting cooling air passing through the main channel from the blade surface ejection ports along at least one of the blade surfaces to the outside, The main channel comprises an inlet channel portion and a blade body cooling channel portion, wherein the inlet channel portion extends from the inlet to a boundary between the platform and the blade body, and the blade body cooling channel portion comprises three or more odd-numbered in-blade channels extending in the blade body along the blade height direction. An odd number of the blade inner passages are arranged along the arc line of the blade body from the introduction passage portion toward the front side, The adjacent blade inner passages among the odd number of the blade inner passages are connected to each other at one end of one end on the hub side and one end on the blade tip side, so that the blade body cooling passage portion forms a serpentine passage with undulating passages along the blade height direction. The plurality of front ejection holes are connected to the first blade inner passage closest to the front side among the odd number of blade inner passages. The plurality of membrane holes are in communication with the first blade inner channel among the odd number of blade inner channels and at least one blade inner channel among the second blade inner channels adjacent to the first blade inner channel. With the center position of the blade body in the blade height direction as a reference, the area of ​​the blade surface outlet per unit area, i.e., the opening ratio, is higher on the hub side than on the tip side.

2. The moving blade according to claim 1, wherein: With the center position of the blade body in the blade height direction as a reference, the number of the blade surface ejection ports is greater on the hub side than on the blade tip side.

3. The moving blade according to claim 1, wherein: The blade surface outlet is present only on the hub side and not on the blade tip side, with the center position of the blade body in the blade height direction as a reference.

4. The moving blade according to any one of claims 1 to 3, wherein: The plurality of membrane holes are communicated with only the first intra-blade passage among the odd number of intra-blade passages.

5. The moving blade according to any one of claims 1 to 3, wherein: The blade surface spray outlet is formed only on the negative pressure surface.

6. The moving blade according to any one of claims 1 to 3, wherein: With the center position of the blade body in the blade height direction as a reference, the area of ​​the front ejection port per unit area on the blade tip side, i.e., the opening ratio, is higher than that on the hub side.

7. The moving blade according to any one of claims 1 to 3, wherein: The cooling air passage has a blade tip extraction hole that is communicated with one end of the first blade inner passage on the blade tip side and can eject cooling air that has passed through the first blade inner passage from the blade tip surface.

8. The moving blade according to any one of claims 1 to 3, further comprising, in addition to the first cooling air passage, a second cooling air passage formed over the blade root, the platform and the blade body and through which cooling air can flow, The second cooling air passage has: a main passage, which is arranged on one side of the trailing edge relative to the leading edge, i.e., on the rear side, with respect to the first cooling air passage, and has an inlet opening on the surface of the blade root and into which cooling air can flow; and A plurality of rear ejection holes having rear ejection ports capable of ejecting cooling air passing through the main passage from the rear edge to the outside, The main channel in the second cooling air channel has an inlet channel portion and a blade body cooling channel portion, the inlet channel portion extending from the inlet in the second cooling air channel to the boundary between the platform and the blade body, and the blade body cooling channel portion having a plurality of in-blade channels extending in the blade body along the blade height direction, The plurality of blade intra-channels in the second cooling air channel are arranged along the arc line of the blade body from the introduction channel portion in the second cooling air channel toward the rear side, The adjacent inner blade passages among the plurality of inner blade passages in the second cooling air passage are connected to each other at one end of one of the end on the hub side and the end on the blade tip side, so that the blade body cooling passage portion in the second cooling air passage constitutes a serpentine passage in which the passage undulates along the blade height direction. The plurality of rear ejection holes communicate with a rearmost blade inner passage located closest to the rear side among the plurality of blade inner passages in the second cooling air passage.

9. A gas turbine comprising a plurality of the moving blades according to any one of claims 1 to 3, and comprising: a rotor shaft capable of rotating about an axis line and having a plurality of the moving blades arranged and mounted in a circumferential direction relative to the axis line; and a turbine housing covering the plurality of moving blades and the outer circumference of the rotor shaft, The moving blades are mounted on the rotor shaft in the following manner, that is, the blade height direction becomes the radial direction relative to the axis, the hub side becomes the radially outer side of the radially inner side and the radially outer side in the radial direction relative to the axis, and the front side becomes the upstream side of the axis in the axial direction in which the axis extends and the downstream side of the axis.

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