Gas turbine blades and gas turbine

Abstract

One embodiment of a gas turbine blade has a platform with a groove recessed from the trailing edge end face toward the leading edge. The bottom of the groove, viewed radially, overlaps at least with the blade-shaped portion. When the end of the platform on the ventral side facing the bottom is designated as a first point, a tangent extending from the first point along a radially intersecting surface in the bottom is designated as a first tangent. When the intersection of the line segment connecting the trailing edge end of the serpentine cooling flow path located inside the blade-shaped portion (viewed radially) and the trailing edge end of the blade-shaped portion with the bottom is designated as a second point, a tangent extending from the aforementioned surface in the bottom at the second point is designated as a second tangent. The intersection of the first and second tangents, viewed radially, is designated as a third point. Viewed radially, the third point exists on the opposite side of the trailing edge end of the blade-shaped portion, separated by the straight line connecting the first and second points. This invention effectively suppresses thermal stress generated in the gas turbine blade.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a gas turbine blade and a gas turbine. BACKGROUND

[0002] For a gas turbine blade, a temperature difference is likely to occur between a profile portion and a platform in a transition state such as at the start of operation of a gas turbine, at the stop of operation, and the like, and thermal stress is likely to occur. It is known that the thermal stress is particularly likely to become large in the vicinity of a trailing edge of the profile portion and a root of the platform. Therefore, a gas turbine blade is known that is configured to reduce the above-described thermal stress by forming a groove portion in the platform, the groove portion being formed so as to be recessed from an end portion on the trailing edge side of the platform toward the leading edge side and extending in the circumferential direction of the rotor (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 8-254103 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] For a turbine blade, a serpentine cooling flow path is formed in the inside of a profile portion for cooling of the profile portion. The serpentine cooling flow path extends over a range in the blade height direction including at least a portion of a platform. Therefore, the above-described groove portion formed in the platform needs to be formed at a position at which a wall thickness of the serpentine cooling flow path is secured. Therefore, the depth of the groove portion is limited.

[0008] In view of the above-described circumstances, an object of at least one embodiment of the present disclosure is to provide a gas turbine blade that can effectively suppress thermal stress generated in a gas turbine blade.

[0009] TECHNICAL SOLUTION

[0010] (1) A gas turbine blade according to at least one embodiment of the present disclosure includes:

[0011] a base end portion fixed to a rotor;

[0012] a blade-shaped portion extending in a radial direction of the rotor, having a blade surface of a pressure side and a suction side that form a blade shape between a leading edge and a trailing edge; and

[0013] a platform provided between the base end portion and the blade-shaped portion, the platform having a groove portion recessed from an end surface on the trailing edge side toward the leading edge side and extending in the circumferential direction of the rotor,

[0014] a bottom portion of the groove portion at least overlaps with the blade-shaped portion when viewed in the radial direction,

[0015] When the end of the ventral side of the platform in the bottom is designated as the first point, the tangent in the bottom extending from the first point along the surface intersecting the radial direction is designated as the first tangent.

[0016] When the intersection of the line segment connecting the end of the trailing edge side of the serpentine cooling flow path located inside the blade-shaped portion when viewed from the radial direction and the end of the trailing edge side of the blade-shaped portion with the bottom is designated as the second point, the tangent line extending along the surface of the bottom at the second point is designated as the second tangent line.

[0017] When the intersection of the first tangent and the second tangent when viewed radially is set as the third point,

[0018] When viewed from the radial direction, the third point exists on the opposite side of the trailing edge end of the blade-shaped portion, separated by the straight line connecting the first point and the second point.

[0019] (2) The gas turbine of at least one embodiment of the present disclosure comprises:

[0020] The rotor; and

[0021] The gas turbine blades of (1) described above are fixed to the rotor at the base end.

[0022] Beneficial effects

[0023] According to at least one embodiment of this disclosure, thermal stress generated in the moving blades of a gas turbine can be effectively suppressed. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a gas turbine with moving blades that employs some implementation methods.

[0025] Figure 2 This is a diagram showing the moving blades (gas turbine moving blades) of some embodiments viewed from the rear side.

[0026] Figure 3A It means Figure 2 A diagram of an example of an AA section.

[0027] Figure 3B It means Figure 2 A diagram of another example of an AA section.

[0028] Figure 3C It means Figure 2 A diagram of another example of the AA section.

[0029] Figure 3D It means Figure 2 A diagram of another example of the AA section.

[0030] Figure 4 is a diagram for describing the shape of the groove portion. DETAILED DESCRIPTION

[0031] Hereinafter, some embodiments of the present disclosure will be described with reference to the drawings. However, the size, material, shape, and relative arrangement of the constituent parts described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure to the embodiments, but are merely illustrative.

[0032] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" indicating relative or absolute arrangement not only strictly indicate such arrangement, but also indicate a state in which the relative displacement is performed with an angle or a distance having a tolerance or to the extent that the same function can be obtained.

[0033] For example, expressions such as "same", "equal", and "homogeneous" indicating that things are in an equal state not only strictly indicate an equal state, but also indicate a state in which there is a tolerance or a difference to the extent that the same function can be obtained.

[0034] For example, expressions such as quadrangular shape, cylindrical shape, and the like indicating shape not only indicate shapes such as quadrangular shape, cylindrical shape, and the like in a strict geometrical sense, but also indicate shapes including concave-convex portions, chamfered portions, and the like within a range in which the same effect can be obtained.

[0035] On the other hand, expressions such as "provided with", "including", "having", "comprising", or "possessing" one constituent element are not exclusive expressions excluding the existence of other constituent elements.

[0036] (Gas turbine 1)

[0037] First, a gas turbine to which a gas turbine moving blade according to some embodiments is applied will be described.

[0038] Figure 1 is a schematic configuration diagram of a gas turbine to which a gas turbine moving blade according to some embodiments is applied. As shown in Figure 1 the gas turbine 1 is provided with a compressor 2 for generating compressed air, a combustor 4 for generating combustion gas using the compressed air and fuel, and a turbine 6 configured to be rotationally driven by the combustion gas. In the case of the gas turbine 1 for power generation, a generator not shown is linked to the turbine 6.

[0039] The compressor 2 includes a plurality of stationary blades 16 fixed to the compressor casing 10 side and a plurality of moving blades 18 planted to the rotor 8 in an alternating arrangement with the stationary blades 16.

[0040] The air introduced from the air introduction port 12 is sent to the compressor 2, and the air is compressed by the plurality of stator vanes 16 and the plurality of rotor vanes 18, thereby becoming compressed air of high temperature and high pressure.

[0041] The fuel and the compressed air generated by the compressor 2 are supplied to the combustor 4, in which the fuel is combusted, and combustion gas as a working fluid of the turbine 6 is generated. As shown in Figure 1 The combustor 4 can be disposed in plurality in the casing 20 in the circumferential direction around the rotor 8.

[0042] The turbine 6 has a combustion gas flow path 28 formed in a turbine chamber 22, and the turbine 6 includes a plurality of stator vanes 24 and rotor vanes 26 provided in the combustion gas flow path 28.

[0043] The stator vanes 24 are fixed to the turbine chamber 22 side, and a plurality of stator vanes 24 arranged in the circumferential direction of the rotor 8 constitute a stator vane row. Further, the rotor vanes 26 are planted to the rotor 8, and a plurality of rotor vanes 26 arranged in the circumferential direction of the rotor 8 constitute a rotor vane row. The stator vane row and the rotor vane row are alternately arranged in the axial direction of the rotor 8.

[0044] In the turbine 6, the combustion gas from the combustor 4 flowing into the combustion gas flow path 28 is passed through the plurality of stator vanes 24 and the plurality of rotor vanes 26, thereby rotationally driving the rotor 8, and thereby a generator coupled to the rotor 8 is driven to generate electric power. The combustion gas after driving the turbine 6 is discharged to the outside via an exhaust chamber 30.

[0045] In some embodiments, the rotor vane 26 of the turbine 6 can be a gas turbine vane 40 described below.

[0046] (Gas turbine vane 40)

[0047] Figure 2 is a view of the rotor vane 26 (gas turbine vane 40) of some embodiments viewed from the back side.

[0048] Figure 3A is a view of one example of an A-A cross section of Figure 2 .

[0049] Figure 3B is a view of another example of an A-A cross section of Figure 2 .

[0050] Figure 3C is a view of yet another example of an A-A cross section of Figure 2 .

[0051] Figure 3D is a view of still another example of an A-A cross section of Figure 2 .

[0052] Figure 4 is a view for explaining the shape of the groove portion 70, and Figure 3A The groove portion 70 shown in FIG. 8 is an example.

[0053] Note that, Figure 3A , Figure 3B , Figure 3C and Figure 3D The A-A cross section shown in FIG. 8 indicates the cross section of the blade portion 42 at the end portion on the radially outer side of the rotor 8 at the rounded portion 36 described later (hereinafter, also simply referred to as "radially outer side").

[0054] As shown in FIG. 8, the blade 26 of the gas turbine blade 40 according to some embodiments is provided with a blade portion (blade-shaped portion) 42, a platform 32, and a blade root portion (base end portion) 34. The blade root portion 34 is embedded in the rotor 8 (refer to FIG. 1), and the blade 26 rotates together with the rotor 8. The platform 32 is integrally formed with the blade root portion 34. Figure 2 , Figure 3A , Figure 3B , Figure 3C and Figure 3D The blade portion 42 is provided so as to extend in the radial direction (hereinafter, also simply referred to as "radial direction") of the rotor 8, and has a base end 50 fixed to the platform 32 and a tip end 48 located on the opposite side of the base end 50 in the blade height direction (radial direction of the rotor 8). Figure 1

[0055] Further, the blade portion 42 of the blade 26 has a leading edge 44 and a trailing edge 46 from the base end 50 to the tip end 48, and the blade surface of the blade portion 42 includes a pressure surface (abdominal surface) 56 and a negative pressure surface (back surface) 58 extending between the base end 50 and the tip end 48 in the blade height direction (radial direction).

[0056] As shown in FIG. 8, a cooling flow path 60 extending in the blade height direction of the blade portion 42 is provided inside the blade portion 42. A cooling fluid (for example, air) for cooling the gas turbine blade 40 flows in the cooling flow path 60. The blade portion 42 provided in the combustion gas flow path 28 of the turbine 6 and exposed to the high-temperature combustion gas is cooled by supplying the cooling fluid to the cooling flow path 60.

[0057] Figure 3A , Figure 3B , Figure 3C and Figure 3D The cooling flow path 60 extends over the range of the blade height direction including at least a portion of the blade portion 42 and the platform 32 in some embodiments.

[0058]

[0059] ​​​Note that the gas turbine blade 40 can have a plurality of cooling flow paths 60. Further, the cooling flow paths 60 can extend throughout the blade root 34.

[0060] A fillet 36 is formed at a base end portion 51 of a portion on the base end 50 side of the blade portion 42. Also, the blade portion 42 is connected to the platform 32 via the fillet 36.

[0061] As shown in Figs. 1 and 2, the platform 32 of the blade 26 has a recessed portion 50 that is recessed toward the front edge 44 side from an end surface 32a of the platform 32 on the rear edge 46 side. Figure 2 、 Figure 3A 、 Figure 3B 、 Figure 3C and Figure 3D As shown in Figs. 1 and 2, the platform 32 of the blade 26 has a recessed portion 50 that is recessed toward the front edge 44 side from an end surface 32a of the platform 32 on the rear edge 46 side.

[0062] For the blade 26, a temperature difference is likely to occur between the blade portion 42 and the platform 32 in a transient state at the start of operation of the gas turbine 1, at the stop of operation, and the like, and a thermal stress is likely to occur. It is known that this thermal stress is particularly likely to become large in the vicinity of the root of the platform 32 and the rear edge 46 of the blade portion 42. Therefore, the above-described thermal stress is reduced by forming the slot portion 70 in the platform 32, which is formed so as to be recessed toward the front edge 44 side from the end surface 32a of the platform 32 on the rear edge 46 side and extend in the circumferential direction of the rotor 8.

[0063] The slot portion 70 will be described in detail later.

[0064] As shown in Figs. 1 and 2, the platform 32 of the blade 26 has a recessed portion 50 that is recessed toward the front edge 44 side from an end surface 32a of the platform 32 on the rear edge 46 side. Figure 2 、 Figure 3A 、 Figure 3B 、 Figure 3C and Figure 3D As shown in Figs. 1 and 2, the platform 32 of the blade 26 has a recessed portion 50 that is recessed toward the front edge 44 side from an end surface 32a of the platform 32 on the rear edge 46 side.

[0065] For the blade 26, the end surface 32c of the pressure surface 56 side (ventral side) of the platform 32 includes a flat surface 32p that can abut against an unillustrated seal pin arranged at a position opposite the end surface 32c.

[0066] (Regarding the slot portion 70)

[0067] As described above, the slot portion 70 is formed so as to be recessed toward the front edge 44 side from the end surface 32a of the platform 32 on the rear edge 46 side. Further, the rear edge 46 of the blade portion 42 is provided close to the end surface 32a of the platform 32 on the rear edge 46 side.

[0068] Therefore, the bottom 71 of the groove portion 70 is formed at a position closer to the leading edge 44 side than the end portion (the trailing edge end 46a) of the blade portion 42 on the trailing edge 46 side of the end surface 32a of the platform 32.

[0069] Note that, for the moving blade 26 of some embodiments, the bottom 71 of the groove portion 70 is located at a position closest to the leading edge 44 side on a cross section of the moving blade 26 when viewed in the circumferential direction, that is, an upstream side of the turbomachine 6 in the axial direction (hereinafter, also simply referred to as "axial direction") of the rotor 8.

[0070] In a transition state at the start of operation of the gas turbine 1, at the stop of operation, and the like, thermal stress acting on the blade portion 42 is particularly likely to become large in the vicinity of the trailing edge 46 of the blade portion 42 and the root of the platform 32.

[0071] As a result of diligent studies by the present inventors, it was ascertained that, in order to effectively suppress the thermal stress in the vicinity of the trailing edge 46 of the blade portion 42 and the root of the platform 32, which are particularly likely to become large thermal stress, it is good to suppress the strength of the region within the platform 32 that confines the root by forming the groove portion 70 in a manner such that the groove portion 70 is present directly below (radially inner side of) the trailing edge end 46a of the blade portion 42.

[0072] However, for the moving blade 26, a serpentine cooling flow path (cooling flow path 60) is formed in the interior of the blade portion 42 for cooling of the blade portion 42. As described above, the cooling flow path 60 extends over a range in the blade height direction including at least a portion of the platform 32. Therefore, the above-described groove portion 70 formed in the platform 32 needs to be formed at a position that ensures a wall thickness from the cooling flow path 60. Therefore, the depth of this groove portion 70 is limited.

[0073] As shown in Figs. 1, 2, and 3, the moving blade 26 includes a blade portion 42 and a platform 32. The blade portion 42 is a portion that extends in the radial direction of the rotor 8 and is provided with a leading edge 44 and a trailing edge 46. The platform 32 is a portion that extends in the axial direction of the rotor 8 and is provided with a pressure surface 56 and a suction surface 58. The platform 32 is connected to the trailing edge 46 of the blade portion 42. Figure 3A , Figure 3B , Figure 3C and Figure 3D As shown in Figs. 1, 2, and 3, the moving blade 26 includes a blade portion 42 and a platform 32. The blade portion 42 is a portion that extends in the radial direction of the rotor 8 and is provided with a leading edge 44 and a trailing edge 46. The platform 32 is a portion that extends in the axial direction of the rotor 8 and is provided with a pressure surface 56 and a suction surface 58. The platform 32 is connected to the trailing edge 46 of the blade portion 42.

[0074] As shown in Figs. 1, 2, and 3, the moving blade 26 includes a blade portion 42 and a platform 32. The blade portion 42 is a portion that extends in the radial direction of the rotor 8 and is provided with a leading edge 44 and a trailing edge 46. The platform 32 is a portion that extends in the axial direction of the rotor 8 and is provided with a pressure surface 56 and a suction surface 58. The platform 32 is connected to the trailing edge 46 of the blade portion 42. Figure 3A , Figure 3B , Figure 3C and Figure 3D As shown in Figs. 1, 2, and 3, the moving blade 26 includes a blade portion 42 and a platform 32. The blade portion 42 is a portion that extends in the radial direction of the rotor 8 and is provided with a leading edge 44 and a trailing edge 46. The platform 32 is a portion that extends in the axial direction of the rotor 8 and is provided with a pressure surface 56 and a suction surface 58. The platform 32 is connected to the trailing edge 46 of the blade portion 42.

[0075] Therefore, for the blade 26 of some embodiments, the position of the trailing edge 46 of the blade portion 42 and the position of the cooling flow path 61 on the trailing edge 46 side are considered as shown in Figure 3A , Figure 3B , Figure 3C and Figure 3D The groove portion 70 is formed so as to be deeper in the vicinity of the trailing edge end 46a of the blade portion 42 and shallower at a position away from the trailing edge end 46a of the blade portion 42 in the circumferential direction, when viewed in the radial direction.

[0076] Specifically, the groove portion 70 includes a back side region 72 that is shallower at a position away from the trailing edge end 46a of the blade portion 42, a belly side region 73 that is deeper in the vicinity of the trailing edge end 46a of the blade portion 42, and an intermediate region 74 that connects the back side region 72 and the belly side region 73.

[0077] More specifically, as shown in Figure 4 The bottom portion 71 of the groove portion 70 overlaps with the blade portion 42 at least when viewed in the radial direction.

[0078] When the end 71a of the bottom portion 71 on the pressure surface 56 side of the platform 32 is set as a first point P1, a tangent line of the bottom portion 71 at the first point P1, that is, a tangent line extending along a plane PL (for example, a plane corresponding to the paper in Figure 4 , is set as a first tangent line Lt1.

[0079] When a line segment Ls connecting the trailing edge end 61a of the cooling flow path 61 on the trailing edge 46 side inside the blade portion 42 and the trailing edge end 46a of the blade portion 42 when viewed in the radial direction and the bottom portion 71 is set as a second point P2, a tangent line of the bottom portion 71 at the second point P2, that is, a tangent line extending along the above-mentioned plane PL is set as a second tangent line Lt2. An intersection point of the first tangent line Lt1 and the second tangent line Lt2 when viewed in the radial direction is set as a third point P3. The third point P3 is present on the opposite side of the trailing edge end 46a of the blade portion 42 across a straight line SL connecting the first point P1 and the second point P2 when viewed in the radial direction.

[0080] Note that, Figure 3A , Figure 3B , Figure 3C and Figure 3D Any of the groove portions 70 shown in

[0081] Note that the first point P1 is an intersection point of the bottom portion 71 and the end surface 32c of the pressure surface 56 side of the platform 32 when viewed in the radial direction, and therefore, the first tangent line Lt1 is not uniquely determined, strictly speaking. Therefore, the above-mentioned first point P1 refers to a position extremely close to the intersection point, that is, a position away from the position having no influence of chamfering or light chamfering in the circumferential direction from the portion where chamfering or light chamfering is performed at the intersection point.

[0082] By configuring the groove portion 70 as described above, the bottom portion 71 is formed at a position closer to the inner side toward the trailing edge 44 side of the end surface 32a of the trailing edge end 46a of the blade portion 42 from the trailing edge 46 side of the platform 32. Therefore, the groove portion 70 exists at a position overlapping the trailing edge end 46a of the blade portion 42 when viewed in the radial direction, and thus the strength of the platform 32 directly below (radially inner side of) the trailing edge end 46a of the blade portion 42 can be suppressed, and thermal stress generated in the vicinity of the trailing edge end 46a of the blade portion 42 in the transient state of the gas turbine 1 can be effectively reduced.

[0083] Further, by configuring the groove portion 70 as described above, the bottom portion 71 is formed toward the end surface 32a of the trailing edge 46 side of the platform 32, that is, toward the axially downstream side of the rotor 8, from the second point P2 toward the negative pressure surface 58. Therefore, the bottom portion 71 suppresses the approach of the cooling flow path 61 from the second point P2 toward the negative pressure surface 58, and thus the wall thickness between the groove portion 70 and the cooling flow path 61 can be easily ensured.

[0084] Therefore, according to the blade 26 of some embodiments, the wall thickness between the groove portion 70 and the cooling flow path 61 can be ensured, and the thermal stress generated in the vicinity of the trailing edge end 46a of the blade portion 42 in the transient state of the gas turbine 1 can be effectively reduced.

[0085] Further, in the gas turbine 1 provided with the blade 26 having the groove portion 70 configured as described above, the wall thickness between the groove portion 70 and the cooling flow path 61 can be ensured, and the thermal stress generated in the vicinity of the trailing edge end 46a of the blade portion 42 in the transient state of the gas turbine 1 can be effectively reduced, and thus the durability of the gas turbine 1 can be improved.

[0086] In the blade 26 of some embodiments, the bottom portion 71 intersects the negative pressure surface 58 and the pressure surface 56 at a position radially outward of the first imaginary circle Cv1 centered on the trailing edge end 46a of the blade portion 42 and passing through the line segment Ls as described above. Note that, Figure 3A 、 Figure 3B 、 Figure 3C and Figure 3D any one of the groove portions 70 illustrated in FIGS. 12 to 15 satisfies this condition.

[0087] The radius of the first imaginary circle Cv1 can be set to a size that can effectively reduce the thermal stress generated in the vicinity of the trailing edge end 46a of the blade portion 42 in the transient state of the gas turbine 1, for example, by stress analysis or the like.

[0088] Thus, the strength of the platform 32 directly below (radially inner side of) the trailing edge end 46a of the blade portion 42 can be efficiently suppressed.

[0089] In the blade 26 of some embodiments, it is preferable that the bottom 71 intersect the low-pressure surface 58 at a position outward of a second imaginary circle Cv2centered on the trailing edge end 61a of the cooling flow path 61 and passing through the line segment Ls, when viewed in the radial direction. Note that Figure 3A , Figure 3B , Figure 3C and Figure 3D any of the groove portions 70 shown in FIGS. 25, 26, 27, and 28 satisfies this condition.

[0090] The radius of the second imaginary circle Cv2is, for example, preferably a thickness required as a wall thickness between the groove portion 70 and the cooling flow path 61.

[0091] Thus, a wall thickness between the groove portion 70 and the cooling flow path 61 of at least the extent of the radius of the second imaginary circle Cv2is ensured.

[0092] In the blade 26 of some embodiments, it is preferable that the depth dp of the end surface of the groove portion 70 (i.e., the end surface 32a of the platform 32 on the trailing edge 46 side) that is recessed toward the leading edge 44 side be deeper on the pressure surface 56 side than on the low-pressure surface 58 side. Specifically, it is preferable that the depth dp of the ventral region 73 be deeper than the depth dp of the dorsal region 72. Note that Figure 3A , Figure 3B , Figure 3C and Figure 3D any of the groove portions 70 shown in FIGS. 25, 26, 27, and 28 satisfies this condition.

[0093] Thus, the depth dp of the groove portion 70 (i.e., the dorsal region 72) of which the contribution to suppressing the strength of the platform 32 directly below (radially inward of) the trailing edge end 46a of the blade portion 42 is low is shallower than the position of the groove portion 70 (i.e., the ventral region 73) of which the trailing edge end 46a is farther away from the low-pressure surface 58 side in the circumferential direction. The groove portion 70 is generally formed by electrical discharge machining, and thus a shallower depth of the groove portion 70 can suppress machining costs.

[0094] Thus, according to the blade 26 of some embodiments, it is possible to provide a groove portion 70 that can effectively suppress the strength of the platform 32 directly below (radially inward of) the trailing edge end 46a of the blade portion 42, and that can suppress machining costs.

[0095] Further, the depth dp of the dorsal region 72 is shallower, and thus the groove portion 70 is less likely to interfere with the seal pin groove 81, and thus it is easy to form the seal pin groove 81 at the end surface 32b of the platform 32 on the low-pressure surface 58 side. Thus, it is also possible to not provide the seal pin groove 81 at the end surface 32c of the platform 32 on the pressure surface 56 side, and thus it is easy to deepen the depth dp of the ventral region 73.

[0096] In the blade 26 of some embodiments, the depth dp of the groove portion 70 can be constant at a position farther from the trailing edge end 46a of the blade portion 42 than the intersection position P4 of the bottom 71 and the low-pressure surface 58 when viewed in the radial direction. Specifically, the depth dp of the groove portion 70 can be constant in at least a portion of the region of the backside region 72. Note that Figure 3A and Figure 3B the groove portion 70 shown in FIG. 27 satisfies this condition.

[0097] Thus, the shape of the groove portion 70 can be simplified, and the processing cost of the groove portion 70 can be suppressed.

[0098] In the blade 26 of some embodiments, the depth dp of the groove portion 70 can be constant in a region including the first point PI and at least a portion between the first point PI and the intersection position P5 of the bottom 71 and the pressure surface 56 when viewed in the radial direction. Specifically, the depth dp of the groove portion 70 can be constant in at least a portion of the region of the abdominal region 73. Note that Figure 3A , Figure 3C and Figure 3D the groove portion 70 shown in FIG. 28 satisfies this condition.

[0099] Thus, the depth of the groove portion 70 on the abdominal side (pressure surface 56 side) can be easily ensured, and interference of a not-shown seal pin for sealing a gap between the platform 32 and an adjacent other blade 26 in the circumferential direction and the groove portion 70 can be avoided.

[0100] Note that the groove portion 70 shown in Figure 3A , Figure 3B , Figure 3C and Figure 3D may extend linearly, but can also extend curvilinearly when viewed in the radial direction.

[0101] In the blade 26 of some embodiments, as described above, the seal pin groove 81 is formed in the end face 32b of the platform 32 on the low-pressure surface 58 side. The end face 32c of the platform 32 on the pressure surface 56 side preferably includes a flat surface 32p that can abut against a not-shown seal pin disposed at a position opposite the end face 32c.

[0102] Thus, the region (flat surface 32p) in which the end face 32c of the platform 32 on the pressure surface 56 side is flat can be easily ensured. Therefore, the groove portion 70 can be easily deepened in the vicinity of the end face 32c of the platform 32 on the pressure surface 56 side. Thus, the strength of the platform 32 directly below (radially inner side of) the trailing edge end 46a of the blade portion 42 can be easily suppressed.

[0103] The present application is not limited to the above-described embodiments, and includes modes in which the above-described embodiments are modified and modes in which these modes are appropriately combined.

[0104] For example, the blade 26 having the groove portion 70 in which the back side region 72, the belly side region 73, and the intermediate region 74 shown in FIGS. 27 to 29 are appropriately combined also functions as described above. Figure 3A , Figure 3B , Figure 3C and Figure 3D The blade 26 having the groove portion 70 in which the back side region 72, the belly side region 73, and the intermediate region 74 shown in FIGS. 27 to 29 are appropriately combined also functions as described above.

[0105] The content described in each of the above-described embodiments is grasped, for example, as described below.

[0106] (1) The gas turbine blade 40 (blade 26) of at least one embodiment of the present disclosure includes a base end portion (blade root portion 34) fixed to the rotor 8, a blade-shaped portion (blade portion 42) extending in the radial direction of the rotor 8 and having a blade surface forming a belly side and a back side between a leading edge 44 and a trailing edge 46, and a platform 32 provided between the base end portion (blade root portion 34) and the blade-shaped portion (blade portion 42). The platform 32 has a groove portion 70 recessed from an end surface 32a on the trailing edge 46 side toward the leading edge 44 side and extending in the circumferential direction of the rotor 8. A bottom portion 71 of the groove portion 70 overlaps at least the blade-shaped portion (blade portion 42) when viewed in the radial direction. When an end portion 71a of the belly side (pressure surface 56 side) of the platform 32 with respect to the bottom portion 71 is set as a first point P1, a tangent line of the bottom portion 71 at the first point P1, that is, a tangent line extending along a plane PL intersecting the radial direction is set as a first tangent line Lt1. When a line segment Ls connecting an end portion (trailing edge end 61a) of the serpentine cooling flow path (cooling flow path 61) provided inside the blade-shaped portion (blade portion 42) when viewed in the radial direction on the trailing edge 46 side and an end portion (trailing edge end 46a) of the blade portion 42 on the trailing edge 46 side intersects the bottom portion 71, a point of intersection is set as a second point P2. When a tangent line of the bottom portion 71 at the second point P2, that is, a tangent line extending along the above-mentioned plane PL is set as a second tangent line Lt2. When a point of intersection of the first tangent line Lt1 and the second tangent line Lt2 when viewed in the radial direction is set as a third point P3. The third point P3 is present on the opposite side of the end portion (trailing edge end 46a) of the blade portion 42 on the trailing edge 46 side across a straight line SL connecting the first point P1 and the second point P2 when viewed in the radial direction.

[0107] According to the above-described (1), the bottom portion 71 is formed at a position closer to the leading edge 44 side from the end surface 32a of the platform 32 on the trailing edge 46 side than the end portion (trailing edge end 46a) of the blade-shaped portion (blade portion 42) on the trailing edge 46 side. Therefore, the groove portion 70 is present at a position overlapping the end portion (trailing edge end 46a) of the blade-shaped portion (blade portion 42) on the trailing edge 46 side when viewed in the blade height direction (radial direction), and thus it is possible to suppress the strength of the platform 32 directly below (radial inner side) of the end portion (trailing edge end 46a) of the blade-shaped portion (blade portion 42) on the trailing edge 46 side, and effectively reduce thermal stress generated in the vicinity of the end portion (trailing edge end 46a) of the blade-shaped portion (blade portion 42) on the trailing edge 46 side in the transient state of the gas turbine 1.

[0108] Furthermore, according to the configuration described in (1) above, the bottom 71 is formed as an end face 32a that extends from the second point P2 toward the trailing edge 46 side of the platform 32 along the blade surface (negative pressure surface 58) toward the back side, i.e., toward the axial downstream side of the rotor 8. Therefore, the bottom 71 prevents the blade surface (negative pressure surface 58) from the second point P2 from approaching the serpentine cooling flow path (cooling flow path 61), thus easily ensuring the wall thickness between the groove 70 and the serpentine cooling flow path (cooling flow path 61).

[0109] Therefore, according to the above (1) configuration, the wall thickness between the groove 70 and the serpentine cooling flow path (cooling flow path 61) can be ensured, and the thermal stress generated near the end (tail edge end 46a) of the blade-shaped part (blade part 42) on the trailing edge 46 side can be effectively reduced in the transition state of the gas turbine 1.

[0110] (2) In some embodiments, in the configuration described in (1) above, when viewed from the radial direction, the bottom 71 is preferably located at a point on the outer side of the first imaginary circle Cv1 on the line segment Ls, centered on the end (tail edge end 46a) on the side of the trailing edge 46 of the blade-shaped portion (blade portion 42), and intersecting the blade surface (negative pressure surface 58) on the back side and the blade surface (pressure surface 56) on the front side.

[0111] Based on the above (2) configuration, the intensity of the platform 32 directly below (radially inward) the end (tail edge end 46a) of the trailing edge 46 side of the blade-shaped part (blade part 42) can be effectively suppressed.

[0112] (3) In some embodiments, in the configuration of (1) or (2) above, when viewed from the radial direction, the bottom 71 is preferably located at a point on the outer side of the blade surface (negative pressure surface 58) that is centered on the end (tail edge end 61a) on the side of the trailing edge 46 of the serpentine cooling flow path (cooling flow path 61) and passes through the second imaginary circle Cv2 on the line segment Ls.

[0113] Based on the above (3) configuration, at least the wall thickness between the groove 70 and the serpentine cooling flow path (cooling flow path 61) can be ensured to be at least the same as the radius of the second imaginary circle Cv2.

[0114] (4) In some embodiments, in any of the configurations described in (1) to (3) above, the depth dp of the groove 70 recessed from the end face on the rear edge 46 side (i.e., the end face 32a on the rear edge 46 side of the platform 32) toward the front edge 44 side is preferably deeper on the ventral side (pressure surface 56 side) than on the dorsal side (negative pressure surface 58 side).

[0115] According to the configuration described above (4), the groove 70 located at a position circumferentially further away from the back side (negative pressure surface 58 side) of the end (tail edge end 46a) on the side of the blade-shaped portion (blade portion 42) has a shallower depth dp than the groove 70 located on the back side (negative pressure surface 58 side) of the end (tail edge end 46a) that contributes less to the strength of the plateau 32. The groove 70 is generally formed by electrical discharge machining, so a shallow depth of the groove 70 can reduce machining costs.

[0116] According to the above (4) configuration, the groove 70 can provide strength of the platform 32 directly below (radially inner side) of the end (tail edge end 46a) on the trailing edge 46 side of the blade-shaped part (blade part 42) and suppress processing costs.

[0117] (5) In some embodiments, in any of the configurations described in (1) to (4) above, the depth dp of the groove 70 recessed from the end face on the trailing edge 46 side (i.e., the end face 32a on the trailing edge 46 side of the platform 32) toward the leading edge 44 side may be fixed at a position (trailing edge end 46a) away from the end of the blade-shaped portion (blade portion 42) on the trailing edge 46 side than the intersection position P4 of the bottom 71 and the blade surface (negative pressure surface 58) when viewed from the radial side.

[0118] Based on the above (5) configuration, the shape of the groove 70 can be simplified and the processing cost of the groove 70 can be reduced.

[0119] (6) In some embodiments, in any of the configurations described in (1) to (5) above, the depth dp of the groove 70 recessed from the end face on the trailing edge 46 side (i.e., the end face 32a on the trailing edge 46 side of the platform 32) toward the leading edge 44 side may be fixed in at least a portion of the region including the first point P1 and the intersection P5 between the first point P1 and the bottom 71 and the ventral blade surface (pressure surface 56) when viewed radially.

[0120] According to the above (6) configuration, it is easy to ensure the depth dp of the groove 70 on the ventral side (pressure surface 56) and avoid interference between the sealing pin used to seal the gap between the platform 32 and the other gas turbine moving blades 40 (moving blades 26) adjacent in the circumferential direction and the groove 70.

[0121] (7) In some embodiments, in any of the configurations described in (1) to (6) above, the platform 32 preferably has a sealing pin groove 81 for accommodating a sealing pin used to seal the gap between the platform 32 and the platform 32 of other gas turbine moving blades 40 (moving blades 26) adjacent in the circumferential direction. The sealing pin groove 81 is preferably formed on the end face 32b of the back side (negative pressure surface 58 side) of the platform 32. The end face 32c of the front side (pressure surface 56) of the platform 32 preferably includes a plane 32p that can abut against a sealing pin disposed opposite to the end face 32c.

[0122] Based on the configuration described in (7) above, it is easy to ensure that the end face 32c on the ventral side (pressure surface 56) of the platform 32 is a planar region (planar surface 32p). Therefore, it is easy to deepen the groove 70 near the end face 32c on the ventral side (pressure surface 56) of the platform 32. As a result, it is easy to suppress the strength of the platform 32 directly below (radially inward) the end (tail edge end 46a) on the trailing edge 46 side of the blade-shaped portion (blade portion 42).

[0123] (8) The gas turbine 1 of at least one embodiment of the present disclosure includes: a rotor 8; and a gas turbine moving blade 40 (moving blade 26) configured in any of (1) to (7) above, which is fixed to the rotor 8 at the base end (blade root 34).

[0124] According to the above configuration (8), the wall thickness between the groove 70 and the serpentine cooling flow path (cooling flow path 61) can be ensured, and the thermal stress generated near the end (tail edge end 46a) of the blade-shaped part (blade part 42) on the trailing edge 46 side during the transition state of the gas turbine 1 can be effectively reduced, thereby improving the durability of the gas turbine 1.

[0125] Explanation of reference numerals in the attached figures

[0126] 1: Gas turbine;

[0127] 8: Rotor;

[0128] 26: Moving leaves;

[0129] 32: Platform;

[0130] 32a, 32b, 32c: End faces;

[0131] 32p: Plane;

[0132] 34: Leaf root (base end);

[0133] 40: Gas turbine motor blades;

[0134] 42: Blade section (blade-shaped section);

[0135] 44: Forefront;

[0136] 46: Trailing edge;

[0137] 46a: Trailing edge;

[0138] 56: Pressure surface (ventral side);

[0139] 58: Negative pressure side (back side);

[0140] 60, 61: Cooling flow path (serpentine cooling flow path);

[0141] 61a: Trailing edge;

[0142] 70: Groove section;

[0143] 71: Bottom;

[0144] 81: Sealing pin groove.

Claims

1. A gas turbine blade comprising: a root portion fixed to a rotor; a blade portion extending in a radial direction of the rotor, having a blade surface of a pressure side and a suction side forming a blade shape between a leading edge and a trailing edge; and a platform provided between the root portion and the blade portion, the platform having a groove portion recessed from an end surface of the trailing edge side toward the leading edge side and extending in a circumferential direction of the rotor, a bottom portion of the groove portion at least overlapping the blade portion when viewed in the radial direction, a first tangent line being a tangent line of the bottom portion at a first point being an end portion of the pressure side of the platform in the bottom portion, the first tangent line extending in a plane intersecting the radial direction, a second tangent line being a tangent line of the bottom portion at a second point being an intersection of the bottom portion and a line segment connecting an end portion of the trailing edge side of a serpentine cooling flow path provided inside the blade portion when viewed in the radial direction and an end portion of the trailing edge side of the blade portion, the second tangent line extending in the plane, a third point being an intersection of the first tangent line and the second tangent line when viewed in the radial direction, the third point being present on an opposite side of the end portion of the trailing edge side of the blade portion from a straight line connecting the first point and the second point when viewed in the radial direction.

2. The gas turbine blade according to claim 1, wherein the bottom portion intersects the blade surface of the suction side and the blade surface of the pressure side at a position farther outside than a first imaginary circle centered on the end portion of the trailing edge side of the blade portion and passing through the line segment when viewed in the radial direction.

3. The gas turbine blade according to claim 1 or 2, wherein the bottom portion intersects the blade surface of the suction side at a position farther outside than a second imaginary circle centered on the end portion of the trailing edge side of the serpentine cooling flow path and passing through the line segment when viewed in the radial direction.

4. The gas turbine blade according to claim 1, wherein a depth of the recess in the groove portion from the end surface of the trailing edge side toward the leading edge side is deeper on the pressure side than on the suction side.

5. The gas turbine blade according to claim 1, wherein the depth of the recess in the groove portion from the end surface of the trailing edge side toward the leading edge side is constant at a position farther from the end portion of the trailing edge side of the blade portion than a position of an intersection of the bottom portion and the blade surface of the suction side when viewed in the radial direction.

6. The gas turbine blade according to claim 1, wherein the depth of the recess in the groove portion from the end surface of the trailing edge side toward the leading edge side is constant in at least a region including the first point and a position of an intersection of the bottom portion and the blade surface of the pressure side when viewed in the radial direction.

7. The gas turbine blade according to claim 1, wherein the platform has a seal pin groove configured for a seal pin for sealing a gap between the platform and a platform of another gas turbine blade adjacent in the circumferential direction, the seal pin groove being formed in an end surface of a suction side of the platform. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The end surface of the platform on the side of the abdomen includes a flat surface that can be in abutment with a sealing pin arranged in a position opposite to the end surface.

8. A gas turbine comprising: the rotor; and The gas turbine blade of claim 1 is fixed to the rotor at the base end portion.

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