JP6745012B1 - Turbine blade and gas turbine equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine blade capable of efficiently cooling a turbine blade and a gas turbine provided with the turbine blade. A turbine blade includes a pressure surface and a suction surface extending between a leading edge and a trailing edge, and a trailing edge including a trailing edge passage opening to the trailing edge and the trailing edge. A turbine blade having a profile, wherein the trailing edge portion faces a pressure surface side wall having an outer surface forming a trailing edge side region of the pressure surface, and faces the pressure surface side wall with the trailing edge passage interposed therebetween. And a suction surface sidewall having an outer surface forming a trailing edge region of the suction surface, the trailing edge portion having a thickness of a first wall that is one of the pressure surface sidewall or the suction surface sidewall. And a second wall, which is the other of the pressure surface side wall and the suction side wall, has a wall thickness decreasing portion that gradually decreases toward a trailing edge, and in the wall thickness decreasing portion, the airfoil portion is formed. The thickness of the first wall is smaller than the thickness of the second wall at an arbitrary position on the coordinate axis along the camber line. [Selection diagram]

Description

The present disclosure relates to a turbine blade and a gas turbine including the turbine blade.

In a turbine blade such as a gas turbine, it is known to cool a turbine blade exposed to a high temperature gas flow by flowing a cooling fluid through a cooling passage formed inside the turbine blade.

For example, Patent Document 1 discloses a turbine blade provided with a plurality of cavities (cooling passages) extending along the blade height direction. The trailing edge portion of the turbine blade is provided with a trailing edge passage that is connected to the cavity and opens to the trailing edge. The trailing edge portion of the turbine blade is cooled by the cooling fluid flowing in the trailing edge passage. It has become so.

JP-A-9-144503

By the way, the turbine blade has an allowable metal temperature depending on the material of the turbine blade, and it is necessary to cool both the pressure surface side and the negative pressure surface side of the turbine blade to the allowable metal temperature or lower.

Here, the heating conditions of the blade wall, including the temperature and flow velocity of the high-temperature gas flowing near the blade surface, may differ between the pressure surface side (antinode side) and the negative pressure surface side (back side) of the turbine blade. In this way, when the heating conditions of the blade wall differ between the pressure surface side and the suction surface side of the turbine blade, the blade wall thickness on the pressure surface side and the blade surface thickness on the suction surface side at the trailing edge are the same. On one of the pressure surface side and the suction surface side, where the above heating condition is severe, the metal temperature on the blade surface (hereinafter, also referred to as the surface metal temperature) becomes higher than the other.

On the other hand, in order to keep both the pressure surface side blade wall and the suction surface side blade wall below the allowable temperature, it is necessary for the surface metal temperature of the blade surface with the higher surface metal temperature to fall below the allowable metal temperature. A significant amount of cooling fluid needs to be supplied to the trailing edge passages of the turbine blade. However, when such an amount of cooling fluid is supplied to the trailing edge passage, the blade wall having the lower surface metal temperature is cooled more than necessary (that is, lower than the allowable metal temperature). In this case, an excessive amount of cooling fluid is supplied to the blade wall having the lower surface metal temperature. Therefore, it is desired to cool the turbine blades more efficiently to improve the efficiency of the entire turbine system.

In view of the above-mentioned circumstances, at least one embodiment of the present invention aims to provide a turbine blade capable of efficiently cooling a turbine blade and a gas turbine including the turbine blade.

A turbine blade according to at least one embodiment of the present invention,
A pressure surface and a suction surface extending between the leading edge and the trailing edge,
A trailing edge portion including the trailing edge and a trailing edge passage opening to the trailing edge;
A turbine blade having an airfoil portion including:
The trailing edge is
A pressure face sidewall having an outer surface forming a trailing edge region of the pressure face;
A suction surface sidewall having an outer surface that is arranged so as to face the pressure surface sidewall with the trailing edge passage interposed therebetween and has an outer surface that forms a trailing edge side region of the suction surface,
The trailing edge portion has a thickness of a first wall which is one of the pressure surface side wall and the suction side wall, and a thickness of a second wall which is the other of the pressure surface side wall and the suction side wall. Has a wall thickness decreasing portion that gradually decreases toward
Wherein the wall thickness reduction portion, wherein at any position in the coordinate axis along the camber line of the airfoil, the thickness of the first wall rather smaller than the thickness of said second wall,
The trailing edge is
A connection region that extends in the trailing edge passage and has a plurality of connection portions that are connected to the pressure surface side wall at one end side and are respectively connected to the negative pressure surface side wall at the other end side,
A rear region behind the connection region,
The wall thickness reducing portion is at least partially within the connection region,
The thickness of the portion of the first wall located in the rear region is smaller than the thickness of the portion of the second wall located in the rear region .

Further, the gas turbine according to at least one embodiment of the present invention,
With the turbine blade described above,
A combustor for producing a combustion gas flowing through a combustion gas passage provided with the turbine blade;
Equipped with.

According to at least one embodiment of the present invention, a turbine blade capable of efficiently cooling a turbine blade and a gas turbine including the turbine blade are provided.

1 is a schematic configuration diagram of a gas turbine to which a turbine blade according to an embodiment is applied. FIG. 3 is a schematic view of turbine blades (moving blades) according to one embodiment as viewed in a direction from a pressure surface to a suction surface (direction along a rotor circumferential direction). It is a schematic sectional drawing of the turbine blade which concerns on one Embodiment, and is equivalent to the sectional view on the AA arrow of FIG. It is a schematic sectional drawing of the turbine blade which concerns on one Embodiment, and is equivalent to the sectional view on the AA arrow of FIG. FIG. 4 is an enlarged cross-sectional view showing the vicinity of the trailing edge portion of the turbine blade shown in FIG. 3. FIG. 3 is a schematic cross-sectional view of a turbine blade according to an embodiment, which is an enlarged cross-sectional view showing the vicinity of a trailing edge portion of a turbine blade. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the trailing edge portion of the turbine blade shown in FIG. 4. It is a schematic diagram which overlaps with the cross section of the trailing edge part of the turbine blade installed in the gas turbine, and the temperature distribution in this cross section. It is the schematic which looked at the turbine blade (stator vane) concerning one embodiment in the direction which goes from a pressure side to a suction side (direction along a rotor peripheral direction).

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Absent.

(Composition of gas turbine)
First, a gas turbine to which turbine blades according to some embodiments are applied will be described.
FIG. 1 is a schematic configuration diagram of a gas turbine to which a turbine blade according to an embodiment is applied. As shown in FIG. 1, a gas turbine 1 is driven to rotate by a compressor 2 for generating compressed air, a combustor 4 for generating combustion gas using compressed air and fuel, and a combustion gas. And a turbine 6 configured as described above. In the case of the gas turbine 1 for power generation, the turbine 6 is connected to a generator (not shown).

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 in the rotor 8 so as to be alternately arranged with respect to the stationary blades 16. .. The air taken in from the air intake 12 is sent to the compressor 2, and this air passes through the plurality of stationary blades 16 and the plurality of moving blades 18 and is compressed, so that the high temperature and high pressure are obtained. It becomes compressed air.

Fuel and compressed air generated by the compressor 2 are supplied to the combustor 4, and the fuel and compressed air are mixed and combusted in the combustor 4, and the working fluid of the turbine 6 is supplied. Combustion gas is generated. As shown in FIG. 1, a plurality of combustors 4 may be arranged in the casing 20 along the circumferential direction around the rotor.

The turbine 6 has a combustion gas passage 28 formed in the turbine casing 22, and includes a plurality of stationary blades 24 and moving blades 26 provided in the combustion gas passage 28. The stationary blades 24 are fixed to the turbine casing 22 side, and the plurality of stationary blades 24 arranged along the circumferential direction of the rotor 8 form a stationary blade row. The moving blades 26 are implanted in the rotor 8, and the plurality of moving blades 26 arranged along the circumferential direction of the rotor 8 form a moving blade row. The stationary blade rows and the moving blade rows are arranged alternately in the axial direction of the rotor 8.

In the turbine 6, the combustion gas from the combustor 4 that has flowed into the combustion gas passage 28 passes through the plurality of stationary blades 24 and the plurality of moving blades 26, whereby the rotor 8 is rotationally driven, and as a result, the rotor 8 is connected. The generated generator is driven to generate electric power. The combustion gas after driving the turbine 6 is exhausted to the outside via the exhaust chamber 29.

In some embodiments, at least one of rotor blades 26 or vanes 24 of turbine 6 are turbine blades 30 described below.

(Composition of turbine blades)
Hereinafter, turbine blades 30 according to some embodiments will be described in more detail. 2 and 9 are schematic views of the turbine blade 30 according to the embodiment as seen in the direction from the pressure surface to the suction surface (direction along the rotor circumferential direction). Of these, FIG. 2 is a diagram showing a moving blade 26 as the turbine blade 30, and FIG. 9 is a diagram showing a stationary blade 24 as the turbine blade 30. 3 and 4 are schematic cross-sectional views orthogonal to the blade height direction of the turbine blade 30 according to the embodiment, and correspond to cross-sectional views taken along the line AA of FIG. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the trailing edge portion of the turbine blade 30 shown in FIG. FIG. 6 is a schematic cross-sectional view orthogonal to the blade height direction of the turbine blade 30 according to the embodiment, and is an enlarged cross-sectional view showing the vicinity of the trailing edge portion of the turbine blade. FIG. 7 is an enlarged cross-sectional view showing the vicinity of the trailing edge portion of the turbine blade 30 shown in FIG.

As shown in FIG. 2, the turbine blade 30 (moving blade 26) according to the embodiment includes a platform 32 and an airfoil portion 34 and a blade root portion 36 connected to the platform 32.

The airfoil portion 34 extends in the blade height direction (span direction), has a base end 38 and a tip 40 that are both ends in the blade height direction, and is connected to the platform 32 on the base end 38 side. ing. Further, the airfoil portion 34 has a leading edge 42 and a trailing edge 44 that extend along the blade height direction, and also has a pressure surface 46 and a suction surface 48 that extend between the leading edge 42 and the trailing edge 44. ..

The blade root portion 36 is located on the opposite side of the airfoil portion 34 with the platform 32 interposed therebetween in the blade height direction. The blade root portion 36 includes an engaging portion 37 having an uneven shape, and the engaging portion 37 is engaged with a blade groove provided in a rotor disk (not shown) that rotates together with the rotor 8 to thereby generate the turbine blade 30. Are attached to the rotor 8 of the turbine 6.

As shown in FIG. 9, a turbine blade 30 (stator vane 24) according to one embodiment includes an airfoil 34, an inner shroud 84 located radially inward of the airfoil 34, and an airfoil 34. And an outer shroud 86 located radially outward with respect to. The outer shroud 86 is supported by the turbine casing 22 (see FIG. 1 ), and the vanes 24 are supported by the turbine casing 22 via the outer shroud 86.

The airfoil portion 34 extends in the blade height direction (span direction), has an inner end 80 and an outer end 82 that are both ends in the blade height direction, and is connected to the inner shroud 84 on the inner end 80 side. And is connected to the outer shroud 86 at the outer end 82 side. Further, the airfoil portion 34 has a leading edge 42 and a trailing edge 44 that extend along the blade height direction, and also has a pressure surface 46 and a suction surface 48 that extend between the leading edge 42 and the trailing edge 44. ..

When the turbine blade 30 (the moving blade 26) is attached to the rotor 8 or the turbine blade 30 (the stationary blade 24) is supported by the turbine casing 22, the blade height direction is the same as that of the turbine 6. The direction is along the radial direction. That is, the blade height direction of the turbine blade 30 and the radial direction of the turbine 6 substantially match.

In the following, the turbine blade 30 will be described with reference to the drawing of the moving blade 26, but basically the same description can be applied to the stationary blade 24 as the turbine blade 30.

As shown in FIGS. 3 and 4, the turbine blade 30 includes a plurality of cavities 60 a, 60 b, 60 c (hereinafter collectively referred to as the cavity 60) that extend along the blade height direction at least inside the airfoil portion 34. I say.). In the exemplary embodiment shown in FIGS. 3 and 4, ribs 58 extending along the blade height direction and partitioning the internal space of the airfoil 34 are provided between the adjacent cavities 60. A plurality of cavities 60 are formed by the inner wall surface of the portion 34 and the ribs 58. The plurality of cavities 60 may communicate with each other to form a meandering flow path (serpentine flow path).
Note that in the exemplary embodiment shown in FIGS. 3 and 4, three cavities 60 are provided inside the airfoil 34, but the number of cavities provided in the airfoil 34 is not limited.

A cooling fluid (for example, air or steam) is supplied to the cavity 60, and the turbine blade 30 is cooled by the cooling fluid flowing through the cavity 60.

In some embodiments, the airfoil 34 is provided with film holes 62, 64 that connect to the cavity 60 and open to the pressure surface 46 or suction surface 48. A part of the cooling fluid flowing through the cavity 60 is guided to the outer wall surface (pressure surface 46 or suction surface 48) of the turbine blade 30 through the film holes 62 and 64, and forms a film boundary layer of the cooling fluid covering the wall surface. To do. As a result, the outer wall surface (pressure surface 46 or negative pressure surface 48) of the turbine blade 30 is cooled.

In the exemplary embodiment shown in FIG. 3, the airfoil 34 is provided with a film hole 62 that connects to the cavity 60 and opens to the suction surface 48. Also, in the exemplary embodiment shown in FIG. 4, the airfoil 34 is provided with a film hole 64 that connects to the cavity 60 and opens to the pressure surface 46.

The airfoil 34 has a trailing edge 50 that includes a trailing edge 44 and a trailing edge passage 52 that opens into the trailing edge 44. The trailing edge passage 52 is located on the leading edge side of the cavity 60 in the cord direction of the airfoil 34, and is connected to the cavity 60 (the cavity 60c in the illustrated example) inside the airfoil 34.

The trailing edge portion 50 has a pressure surface side wall 54 and a suction surface side wall 56. As shown in FIGS. 5-7, the pressure face sidewall 54 has an outer surface 54 b that forms a trailing edge region of the pressure face 46. Further, the suction surface side wall 56 has an outer surface 56 b forming a trailing edge side region of the suction surface 48. The pressure surface side wall 54 and the suction surface side wall 56 are provided so as to face each other with the trailing edge passage 52 in between. That is, the trailing edge passage 52 is at least partially formed by the inner surface 54 a of the pressure surface side wall 54 and the inner surface 56 a of the suction surface side wall 56.

In addition, the trailing edge portion 50 has a wall thickness reducing portion 104 in which the thickness of the pressure surface side wall 54 and the suction surface side wall 56 gradually decreases toward the trailing edge in the cord direction. Here, in the present specification, the thickness of the blade wall such as the pressure surface side wall 54 and the suction surface side wall 56 is the thickness of the airfoil portion 34 in the direction orthogonal to the camber line Lc.

Then, in the wall thickness reducing portion 104, at any position on the coordinate axis along the camber line Lc of the airfoil portion 34, the thickness of the first wall 101, which is one of the pressure surface sidewall 54 or the suction surface sidewall 56, is It is smaller than the thickness of the second wall 102 which is the other of the surface side wall 54 and the suction side wall 56. That is, in the wall thickness reducing portion 104, the thickness t1 of the first wall 101 along the straight line L _P (see FIGS. 5 to 7) orthogonal to the camber line Lc at any position on the camber line Lc is the same. smaller than the thickness t2 of the second wall 102 along a straight line _{L P} also (see FIGS. 5 to 7).

For example, in the exemplary embodiments shown in FIGS. 3, 5 and 6, in the wall thickness reduced portion 104, the thickness t1 of the pressure surface side wall 54 as the first wall 101 is the suction surface as the second wall 102. It is smaller than the thickness t2 of the side wall 56. Further, in the exemplary embodiment shown in FIGS. 4 and 7, in the wall thickness reduced portion 104, the thickness t1 of the suction surface side wall 56 as the first wall 101 is smaller than that of the pressure surface side wall 54 as the second wall 102. It is smaller than the thickness t2.

Here, FIG. 8 is a schematic diagram showing the cross section of the trailing edge portion 50 of the turbine blade 30 installed in the gas turbine 1 (cross section orthogonal to the camber line Lc) and the temperature distribution in this cross section in an overlapping manner. .. As shown in FIG. 8, in the turbine blade 30 arranged in the combustion gas flow passage 28 in the gas turbine 1, the pressure surface 46 faces the pressure surface side region 28P of the combustion gas flow passage 28, and the negative pressure surface. 48 faces the negative pressure surface side region 28S of the combustion gas passage 28.
In FIG. 8, the outer surface of the suction surface side wall 56 is shown by a broken line and reference numeral 56b′ when it is assumed that the pressure surface side wall 54 and the suction surface side wall 56 have the same thickness. The temperature T _A shown by the chain line in the figure is the allowable metal temperature of the turbine blade 30.

In the following, referring to FIG. 8, the case where the blade wall heating conditions are more severe on the suction surface 48 side than on the pressure surface 46 side will be described. Even in the case where the heating condition is more severe, the same description can be made by appropriately replacing the pressure surface 46 and the negative pressure surface 48 in the following description.

The pressure surface 46 side and the negative pressure surface 48 side of the turbine blade 30 may have different blade wall heating conditions including the temperature and flow velocity of the hot gas flowing near the blade surface. In the example shown in FIG. 8, the gas temperature T _S in the negative pressure surface side region 28S of the combustion gas passage 28 facing the negative pressure surface 48 is the gas temperature T _S in the pressure surface side region 28P of the combustion gas passage 28 facing the pressure surface 46. The temperature is higher than the temperature T _P , that is, the heating condition of the turbine blade 30 is more severe on the negative pressure surface 48 side. It should be noted that the faster the flow velocity of the high temperature gas in the pressure surface side region 28P or the negative pressure surface side region 28S, the higher the heat transfer coefficient, so the heating condition becomes more severe.

Under the above conditions, if the pressure side wall 54 and the suction side wall 56 have the same thickness (in this case, the outer surface 56b' of the suction side wall 56), the metal temperature of the pressure side wall 54 is set to the allowable temperature. In order to reduce to TA (that is, to reduce the metal temperature of the outer surface 54b, which is the maximum metal temperature of the pressure side wall 54, to the allowable temperature TA), the cooling fluid of the temperature T _C that needs to be supplied to the trailing edge passage 52 Is assumed to be V ₀ .

At this time, the difference between the temperature (T _P or T _S ) of the high temperature gas, which is the fluid on the outer surface side of the blade walls (pressure side wall 54 and the suction side wall 56), and the temperature T _C of the cooling fluid, which is the inner surface side fluid ΔT is in pressure surface sidewall 54 is _(T P -T _C), since in the suction side sidewall 56 is _(T S -T _C), is larger in the negative pressure surface side wall 56. Therefore, the temperature gradient in the blade wall is larger in the suction side wall 56 than in the pressure side wall 54. Then, the metal temperature (surface metal temperature) of the outer surface 56b′, which is the maximum metal temperature of the suction surface side wall 56, becomes a temperature T _Q higher than the allowable temperature T _A.

Here, in order to make the surface metal temperature of the suction side wall 56 below the allowable temperature T _A by using the cooling fluid of the temperature Tc, the supply amount of the cooling fluid to the trailing edge passage 52 is increased from the above V _0. Need to let. However, when the supply amount of the cooling fluid is increased in this way, the pressure surface side wall 54 whose heating condition is relatively gentle is further cooled and the temperature is lowered, and the metal temperature (surface metal temperature) of the outer surface 54b becomes It becomes lower than the allowable temperature T _A. In this case, an excessive amount of cooling fluid is supplied to the pressure side wall 54.

In this respect, according to the above-described embodiment, in the wall thickness reduced portion 104 of the trailing edge portion 50, the first wall 101, which is one of the pressure surface side wall 54 and the suction side wall 56 (the suction side wall 56 in FIG. 8), Since the thickness t1 is made smaller than the thickness t2 of the second wall 102 which is the other of the pressure surface side wall 54 or the suction side wall 56 (the pressure surface side wall 54 in FIG. 8), in the thinner first wall 101, The blade cooling effect of the cooling fluid flowing through the edge passage 52 can be relatively enhanced. For example, as shown in FIG. 8, by appropriately adjusting the thickness t1 of the first wall 101 (suction side wall 56), the supply amount of the cooling fluid to the trailing edge passage 52 is kept at V ₀ described above. (That is, without increasing the supply amount of the cooling fluid), the metal temperature on the outer surface 56b (surface metal temperature) can be lowered to the allowable temperature T _A. Alternatively, the difference in surface metal temperature (maximum metal temperature) between the first wall 101 (negative pressure surface side wall 56) and the second wall 102 (pressure surface side wall 54) can be reduced.

As described above, even if there is a difference in the heating conditions of the blade wall between the pressure surface 46 side and the negative pressure surface 48 side (the temperature and the flow velocity of the high-temperature gas flowing near the blade surface), the above-mentioned heating conditions are strict. By making the thickness of one blade wall (first wall 101) smaller than the thickness of the other blade wall (second wall 102), the first wall 101 and the second wall 102 cooled by the cooling fluid. The difference in the surface metal temperature (that is, the maximum metal temperature) can be reduced. Therefore, the trailing edge portion 50 can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade 30. Therefore, the turbine blade 30 can be cooled efficiently.

In some embodiments, the trailing edge 50 has a suction side wall 56 as the first wall 101 and a pressure side wall 54 as the second wall 102, as shown in FIGS. 4 and 7, for example. ..

When the cooling of the outer surface of the turbine blade 30 (for example, film cooling by a cooling fluid from a film hole) is not considered, the heating condition of the turbine blade 30 by the high temperature gas is usually on the negative pressure surface 48 side rather than the pressure surface 46 side. Tougher in. In this respect, according to the above-described embodiment, the suction surface side wall 56 (first wall 101), which is the blade wall on the suction surface 48 side under more severe heating conditions, is thinner than the pressure surface side wall 54 (second wall 102). Therefore, the difference in surface metal temperature between the negative pressure surface side wall 56 (first wall 101) and the pressure surface side wall 54 (second wall 102) cooled by the cooling fluid can be reduced. Therefore, the trailing edge portion 50 can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade 30, and thus the turbine blade 30 can be efficiently cooled.

In the exemplary embodiment shown in FIGS. 4 and 7, airfoil 34 is not provided with a film hole that is connected to cavity 60 (cavities 60 a, 60 b, 60 c) and opens to suction surface 48.

By providing the film hole that opens on the blade surface of the turbine blade 30, the temperature of the blade surface downstream of the film hole (that is, the trailing edge 44 side in the cord direction) is lowered by the cooling fluid flowing out from the film hole. That is, by setting the film hole in front of the trailing edge portion 50, the heating condition of the turbine blade 30 at the trailing edge portion 50 is relaxed.
In this regard, in the above-described embodiment, the film hole that is connected to the cavity 60 located in front of the trailing edge passage 52 and that is open to the suction surface 48 is not provided. For this reason, normally, on the negative pressure surface 48 side where the heating condition of the turbine blade 30 is more severe, the effect of relaxing the heating condition by the installation of such a film hole cannot be obtained. Under such circumstances, in the above-described embodiment, as described above, the suction surface side wall 56 (first wall 101), which is the blade wall on the suction surface 48 side, is replaced with the pressure surface side wall 54 (second wall 102). Since it is thinner than the above, it is possible to reduce the difference in surface metal temperature between the negative pressure surface side wall 56 (first wall 101) and the pressure surface side wall 54 (second wall 102) cooled by the cooling fluid. Therefore, the trailing edge portion 50 can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade 30, and thus the turbine blade 30 can be efficiently cooled.

In the present specification, the front is a direction from the trailing edge 44 to the leading edge 42 in the cord direction of the airfoil portion 34, and the rear is the direction from the leading edge 42 to the trailing edge in the cord direction of the airfoil portion 34. It is a direction toward 44.

In the exemplary embodiment shown in FIGS. 4 and 7, the airfoil 34 is provided with a film hole 64 that is connected to the cavity 60 (cavities 60b and 60c in the illustrated example) and opens to the pressure surface 46. There is.

In the above-described embodiment, the film hole 64 that is connected to the cavity 60 located in front of the trailing edge passage 52 and that opens to the pressure surface 46 is provided. Therefore, normally, on the pressure surface 46 side where the heating conditions of the turbine blade 30 are more gradual, the heating conditions are relaxed by the installation of the film holes 64, so that the heating conditions on the negative pressure surface 48 side become relatively more severe.
In this respect, in the above-described embodiment, as described above, the suction surface side wall 56 (first wall 101), which is the blade wall on the suction surface 48 side, is made thinner than the pressure surface side wall 54 (second wall 102). Therefore, the difference in surface metal temperature between the negative pressure surface side wall 56 (first wall 101) and the pressure surface side wall 54 (second wall 102) cooled by the cooling fluid can be reduced. Therefore, the trailing edge portion 50 can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade 30, and thus the turbine blade 30 can be efficiently cooled.

In some embodiments, the trailing edge 50 has a pressure side wall 54 as the first wall 101 and a suction side wall as the second wall 102, as shown, for example, in FIGS. 3, 5 and 6. 56.

In the exemplary embodiment shown in FIGS. 3 and 5, the airfoil 34 is provided with a film hole 62 that connects to the cavity 60 (cavity 60b in the illustrated example) and opens to the suction surface 48.

In the above-described embodiment, the film hole 62 that is connected to the cavity 60 located in front of the trailing edge passage 52 and that opens to the suction surface 48 is provided. Therefore, normally, on the negative pressure surface 48 side where the heating condition of the turbine blade 30 is more severe, the heating condition is relaxed by the installation of the film hole 62, but therefore, on the pressure surface 46 side, the heating condition is relatively more severe. Become.
In this regard, in the above-described embodiment, the pressure surface side wall 54 (first wall 101), which is the blade wall on the pressure surface 46 side, is made thinner than the negative pressure surface side wall 56 (second wall 102), and therefore is cooled by the cooling fluid. The difference in surface metal temperature between the pressure surface side wall 54 (first wall 101) and the negative pressure surface side wall 56 (second wall 102) can be reduced. Therefore, the trailing edge portion 50 can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade 30, and thus the turbine blade 30 can be efficiently cooled.

In the exemplary embodiment shown in FIGS. 3 and 5, the airfoil 34 is not provided with a film hole that connects to the cavity 60 (cavities 60a, 60b, 60c) and opens to the pressure surface 46.

In the above-described embodiment, the film hole that is connected to the cavity 60 located in front of the trailing edge passage 52 and that is open to the pressure surface 46 is not provided. Therefore, on the pressure surface 46 side, the effect of relaxing the heating condition by the installation of the film hole cannot be obtained.
Under such circumstances, in the above-described embodiment, the pressure surface side wall 54 (first wall 101), which is the blade wall on the pressure surface 46 side, is made thinner than the suction side wall 56 (second wall 102). For example, when the heating condition on the negative pressure surface 48 side in the trailing edge portion 50 is relatively gentle due to the film hole being provided on the negative pressure surface 48 side, the pressure surface cooled by the cooling fluid. The difference in surface metal temperature between the side wall 54 (first wall 101) and the suction side wall 56 (second wall 102) can be reduced. Therefore, the trailing edge portion 50 can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade 30, and thus the turbine blade 30 can be efficiently cooled.

In some embodiments, trailing edge 50 includes a connecting region 70 in which a plurality of connecting portions 72 are provided, as shown, for example, in FIGS. Each of the plurality of connecting portions 72 extends to the trailing edge passage 52, is connected to the pressure surface side wall 54 at one end side, and is connected to the suction surface side wall 56 at the other end side. Then, the wall thickness reduced portion 104 exists at least partially in the connection region 70.
5 to 7, the connection area 70 is the straight line L1 indicating the position of the connection portion 72 located closest to the front edge 42 among the plurality of connection portions 72 in the direction along the camber line Lc, and It extends between a straight line L2 indicating the position of the connecting portion 72 located on the trailing edge 44 side.

According to the above-described embodiment, since the wall thickness reducing portion 104 having the relatively small wall thickness and the relatively low strength is provided at least partially in the connection region 70, the wall surface reduced portion 104 is connected to the pressure surface side wall 54 and the suction surface side wall 56. The connecting portion 72 provided can supplement the strength of the turbine blade 30 in the wall thickness reduced portion 104. Therefore, the turbine blade 30 can be efficiently cooled while ensuring the strength of the turbine blade 30.

In some embodiments, for example, as shown in FIG. 6, the connecting portion 72 includes a middle state portion 73 provided between the pressure side wall 54 and the suction side wall 56 inside the trailing edge passage 52. It may be connected to the pressure side wall 54 and the suction side wall 56. The connecting portion 72 is connected to the pressure surface side wall 54 on one end side and the pressure surface side portion 72a connected to the central state portion 73 on the other end side, and is connected to the suction side wall 56 on one end side. It may also include a suction surface side portion 72b connected to the central state portion 73 at the other end side.

In some embodiments, the connection 72 may be a pin fin that extends inside the trailing edge passage 52. By providing the pin fins in the trailing edge passage 52, the heat transfer coefficient in the trailing edge passage 52 can be improved, whereby the trailing edge portion 50 can be cooled more effectively.

In some embodiments, the entire connection region 70 (that is, the entire region between the straight line L1 and the straight line L2 in the camber line Lc direction in FIGS. 5 to 7) is included in the wall thickness reduced portion 104. Good.

In some embodiments, the trailing edge 50 includes a posterior region 78 posterior to the connecting region 70. 5 to 7, the rear area 78 is an area on the trailing edge side of the straight line L2 in the direction along the camber line Lc. The thickness t _1B of the portion of the first wall 101 located in the rear region 78 is smaller than the thickness t _{2B of the} portion of the second wall 102 located in the rear region 78 (FIG. 5). (See FIG. 7).

According to the above-described embodiment, the thickness t1 of the first wall 101 is equal to or less than the thickness t1 of the first wall 101 not only in the wall thickness reduced portion 104 existing in the connection region 70 but also in the rear region 78 located rearward of the connection region 70. It is smaller than the thickness t2 of the two walls 102. Therefore, also in the rear region 78, it is possible to obtain the effect of reducing the difference in surface metal temperature between the first wall 101 and the second wall 102 cooled by the cooling fluid. Therefore, the trailing edge portion 50 can be cooled more effectively while suppressing the supply amount of the cooling fluid to the turbine blade 30, and the turbine blade 30 can be cooled more efficiently.

In some embodiments, in the wall thickness reduced portion 104, the trailing edge passage 52 has a width w in the orthogonal direction of the camber line Lc that gradually decreases toward the trailing edge 44 and is within a cross section orthogonal to the blade height direction. And has a curved shape.

According to the above-described embodiment, in the wall thickness reduced portion 104, the width w of the trailing edge passage 52 gradually decreases toward the trailing edge 44, and the trailing edge passage 52 is curved in a cross section orthogonal to the blade height direction. Since it has such a shape, the flow velocity of the cooling fluid in the trailing edge passage 52 can be effectively increased. Thereby, the heat transfer coefficient in the trailing edge passage 52 can be increased, and the trailing edge portion of the turbine blade can be cooled more effectively.

In some embodiments, in the wall thickness reduced portion 104, the ratio t1/t2 between the thickness t1 of the first wall 101 and the thickness t2 of the second wall 102 is 0.5 or more and less than 1.

According to the above-described embodiment, since the ratio t1/t2 of the thickness t1 of the first wall 101 and the thickness t2 of the second wall 102 is set to 0.5 or more, after the blade wall is relatively thin, At the edge portion 50, the thinner first wall 101 is not excessively thin, and the strength of the turbine blade 30 can be secured. Further, since the above-mentioned ratio t1/t2 is set to be less than 1, the thickness of the first wall 101 can be made sufficiently smaller than the thickness of the second wall 102, whereby it is cooled by the cooling fluid. The difference in surface metal temperature between the first wall 101 and the second wall 102 can be reduced. Therefore, it is possible to efficiently cool the turbine blade 30 while securing the strength of the turbine blade 30 appropriately.

In some embodiments, the wall thickness reduction rate in the wall thickness reduction section 104 with respect to the position change of the second wall 102 along the camber line Lc is greater than the wall thickness reduction rate of the first wall 101.

According to the above-described embodiment, the wall thickness reduction rate with respect to the position change of the relatively thick second wall 102 along the camber line Lc is set to be larger than the wall thickness reduction rate of the relatively thin first wall 101. Therefore, in the wall thickness reduced portion 104, it is easy to properly secure a relatively thin thickness of the first wall 101. Therefore, it is possible to efficiently cool the turbine blade 30 while appropriately securing the strength of the turbine blade 30.

The turbine blade 30 shown in FIGS. 3 and 4 includes a pressure surface side cavity wall 74 connected to the pressure surface side wall 54 and a suction surface side cavity wall 76 connected to the suction surface side wall 56. The pressure surface side cavity wall 74 connected to the pressure surface side wall 54 has an outer surface 74b forming the pressure surface 46 and an inner surface 74a forming a cavity 60c connected to the trailing edge passage 52. The suction side cavity wall 76 connected to the suction side wall 56 has an outer surface 76b forming the suction surface 48 and an inner surface 76a forming a cavity 60c connected to the trailing edge passage 52.

In some embodiments, one of the pressure side cavity wall 74 and the suction side cavity wall 76 that is connected to the first wall 101 has a thickness equal to that of the pressure side cavity wall 74 and the suction side cavity wall 76. The thickness is smaller than the thickness of the one connected to the second wall 102.
For example, in the exemplary embodiment shown in FIG. 3, the thickness t _1A of the pressure side cavity wall 74 connected to the pressure side sidewall 54, which is the first wall 101, is equal to the suction side wall 56, which is the second wall 102. Is smaller than the thickness t _{2A of the} suction-side cavity wall 76 connected to (see FIG. 5 and FIG. 6).

In the cavity portion in front of the trailing edge portion 50, one of the pressure surface side cavity wall 74 and the suction pressure surface side cavity wall 76 may be formed thick in order to improve the strength. In the exemplary embodiment shown in FIG. 3, the suction side cavity wall 76 is formed relatively thick. In this regard, according to the above-described embodiment, one of the pressure surface side cavity wall 74 and the suction surface side cavity wall 76 that is relatively thin (the pressure surface side cavity wall 74 in the example of FIG. 3) is the trailing edge portion 50. It is connected to the relatively thin first wall 101, and one of the relatively thick ones (in the example of FIG. 3, the suction side cavity wall 76) is connected to the relatively thick second wall 102 of the trailing edge portion 50. In this way, since the size relationship of the thickness of the blade wall between the pressure surface 46 side and the suction surface 48 side is the same in the cavity portion and the wall thickness reduced portion 104 of the trailing edge portion 50, the manufacture of the turbine blade 30 is performed. Is relatively easy.

In some embodiments, one of the pressure side cavity wall 74 and the suction side cavity wall 76 that is connected to the first wall 101 has a thickness equal to that of the pressure side cavity wall 74 and the suction side cavity wall 76. The thickness is larger than the thickness of the one connected to the second wall 102.
For example, in the exemplary embodiment shown in FIG. 4, the thickness t _1A of the suction side cavity wall 76 connected to the suction side wall 56 that is the first wall 101 is equal to the thickness t _1A of the second wall 102. _Is larger than the thickness t _{2A of the} pressure surface side cavity wall 74 connected to (see FIG. 7).

In the cavity portion in front of the trailing edge portion 50, one of the pressure surface side cavity wall 74 and the suction pressure surface side cavity wall 76 may be formed thick in order to improve the strength. In the exemplary embodiment shown in FIG. 4, the suction side cavity wall 76 is formed relatively thick. In this regard, according to the above-described embodiment, one of the pressure surface side cavity wall 74 and the suction surface side cavity wall 76 that is relatively thin (the pressure surface side cavity wall 74 in the example of FIG. 4) is the trailing edge portion 50. It is connected to the relatively thick first wall 101, and one of the relatively thick ones (in the example of FIG. 4, the suction side cavity wall 76) is connected to the relatively thin second wall 102 of the trailing edge portion 50. As described above, even when the relationship between the thickness of the blade walls on the pressure surface 46 side and the suction surface 48 side is reversed between the cavity portion and the wall thickness reduced portion 104 of the trailing edge portion 50, the above-mentioned wall By providing the thickness reducing portion 104, it is possible to reduce the difference in surface metal temperature between the first wall 101 and the second wall 102 cooled by the cooling fluid. Therefore, the trailing edge portion 50 can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade 30. Therefore, the turbine blade 30 can be cooled efficiently.

The contents described in each of the above embodiments are understood as follows, for example.

(1) A turbine blade (30) according to at least one embodiment of the present invention,
A pressure surface (46) and a suction surface (48) extending between the leading edge (42) and the trailing edge (44);
A trailing edge portion (50) including the trailing edge and a trailing edge passageway (52) opening into the trailing edge;
A turbine blade having an airfoil (34) including:
The trailing edge is
A pressure face sidewall (54) having an outer surface (54b) forming a trailing edge region of said pressure face;
A suction surface side wall (56) having an outer surface (56b) arranged to face the pressure surface side wall with the trailing edge passage interposed therebetween and forming a trailing edge side region of the suction surface.
The trailing edge portion has a thickness (t1) of a first wall (101) that is one of the pressure surface sidewall or the suction surface sidewall, and a second wall that is the other of the pressure surface sidewall or the suction surface sidewall. The thickness (t2) of (102) has a wall thickness decreasing portion (104) that gradually decreases toward the trailing edge,
In the wall thickness reduced portion, the thickness of the first wall is smaller than the thickness of the second wall at an arbitrary position on the coordinate axis along the camber line (Lc) of the airfoil portion.

According to the above configuration (1), the thickness of the first wall, which is one of the pressure surface side wall and the suction side wall, is the other of the pressure surface side wall and the suction side wall, in the wall thickness reduced portion of the trailing edge. Since the thickness of the second wall is smaller than that of the second wall, the blade wall cooling effect of the cooling fluid flowing through the trailing edge passage can be relatively increased in the thinner first wall. Therefore, even if there is a difference in the heating conditions of the blade wall between the pressure surface side and the suction surface side (such as the temperature and flow velocity of the high-temperature gas flowing near the blade surface), the above-mentioned one of the heating conditions is severe. By making the thickness of the (first wall) smaller than the thickness of the other blade wall (second wall), the difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be reduced. can do. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade. Therefore, the turbine blade can be cooled efficiently.

(2) In some embodiments, in the configuration of (1) above,
The first wall is the suction side wall.

The conditions for heating the turbine blade with the hot gas are usually more severe on the suction side than on the pressure side. In this regard, according to the configuration of (2) above, the suction surface side wall (first wall), which is the blade surface on the suction surface side under more severe heating conditions, is made thinner than the pressure surface side wall (second wall). The difference in surface metal temperature between the negative pressure side wall (first wall) and the pressure side wall (second wall) cooled by the cooling fluid can be reduced. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade, and thus the turbine blade can be efficiently cooled.

(3) In some embodiments, in the configuration of (2) above,
Inside the airfoil portion, a cavity (60a, 60b, 60c) extending along the blade height direction in front of the trailing edge passage is provided,
The airfoil portion is not provided with a film hole that is connected to the cavity and opens to the suction surface.

By providing the film hole that opens on the blade surface of the turbine blade, the temperature of the blade surface on the downstream side (that is, the trailing edge side) of the film hole decreases due to the cooling fluid flowing out from the film hole. That is, by setting the film hole in front of the trailing edge portion, the heating condition of the turbine blade at the trailing edge portion is relaxed.
In this regard, in the above configuration (3), the film hole that is connected to the cavity located in front of the trailing edge passage and that is open to the suction surface is not provided. For this reason, normally, on the negative pressure surface side where the heating conditions of the turbine blade are more severe, the effect of relaxing the heating conditions cannot be obtained by installing such film holes. Under such circumstances, in the configuration of (3), as described in (2) above, the suction surface side wall (first wall), which is the blade wall on the suction surface side, is replaced by the pressure surface side wall (second wall). Since the thickness is smaller than that of (1), the difference in surface metal temperature between the negative pressure side wall (first wall) and the pressure side wall (second wall) cooled by the cooling fluid can be reduced. Therefore, the trailing edge can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade, and thus the turbine blade can be efficiently cooled.

(4) In some embodiments, in the configuration of (2) or (3) above,
Inside the airfoil portion, a cavity (60a, 60b, 60c) extending along the blade height direction in front of the trailing edge passage is provided,
The airfoil is provided with a film hole (64) connected to the cavity and opening to the pressure surface.

In the configuration of (4) above, a film hole is provided which is connected to the cavity located in front of the trailing edge passage and opens on the pressure surface. Therefore, generally, on the pressure surface side where the heating condition of the turbine blade is more gradual, the heating condition is relaxed by the installation of the film hole, so that on the negative pressure surface side, the heating condition becomes relatively more severe.
In this regard, in the configuration of the above (4), as described in the above (2), the suction surface side wall (first wall) which is the blade wall on the suction surface side is thinner than the pressure surface side wall (second wall). Therefore, the difference in surface metal temperature between the negative pressure surface side wall (first wall) and the pressure surface side wall (second wall) cooled by the cooling fluid can be reduced. Therefore, the trailing edge can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade, and thus the turbine blade can be efficiently cooled.

(5) In some embodiments, in the configuration of (1) above,
The first wall is the pressure side wall,
Inside the airfoil portion, a cavity (60a, 60b, 60c) extending along the blade height direction in front of the trailing edge passage is provided,
The airfoil is provided with a film hole (62) connected to the cavity and opening to the suction surface.

In the above configuration (5), the film hole is provided which is connected to the cavity located in front of the trailing edge passage and opens on the negative pressure surface. Therefore, usually, on the negative pressure surface side where the heating conditions of the turbine blade are more severe, the heating conditions are relaxed by the installation of the film holes, but for this reason, on the pressure surface side, the heating conditions become relatively more severe.
In this regard, in the configuration of (5) above, the pressure surface side wall (first wall), which is the blade on the pressure surface side, is made thinner than the negative pressure surface side wall (second wall), so the pressure cooled by the cooling fluid is reduced. The difference in surface metal temperature between the surface side wall (first wall) and the suction side wall (second wall) can be reduced. Therefore, the trailing edge can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade, and thus the turbine blade can be efficiently cooled.

(6) In some embodiments, in the configuration of (1) or (5) above,
The first wall is the pressure side wall,
Inside the airfoil portion, a cavity (60a, 60b, 60c) extending along the blade height direction in front of the trailing edge passage is provided,
The airfoil is not provided with a film hole connected to the cavity and open to the pressure surface.

In the above configuration (6), the film hole that is connected to the cavity located in front of the trailing edge passage and that is open to the pressure surface is not provided. Therefore, on the pressure surface side, the effect of relaxing the heating condition by the installation of the film hole cannot be obtained.
Under such circumstances, in the configuration of (6) above, the pressure surface side wall (first wall), which is the blade on the pressure surface side, is made thinner than the suction side wall (second wall). Side wall (first wall) that is cooled by the cooling fluid when the heating condition on the negative pressure surface side at the trailing edge is relatively mild due to the fact that a film hole is provided on the side It is possible to reduce the difference in the surface metal temperature between the negative pressure surface side wall (second wall). Therefore, the trailing edge can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blade, and thus the turbine blade can be efficiently cooled.

(7) In some embodiments, in any of the configurations of (1) to (6) above,
The trailing edge portion is provided with a plurality of connecting portions (72) each extending into the trailing edge passage and connected to the pressure surface side wall on one end side and connected to the suction side wall on the other end side. Including a connection area (70) that is
The reduced wall thickness is at least partially within the connection region.

According to the above configuration (7), since the wall thickness reduced portion having the relatively small wall thickness and the relatively low strength is provided at least partially in the connection region, the wall is connected to the pressure surface sidewall and the suction surface sidewall. The connection portion can supplement the strength of the turbine blade in the reduced wall thickness portion. Therefore, the turbine blade can be efficiently cooled while ensuring the strength of the turbine blade.

(8) In some embodiments, in the configuration of (7) above,
The trailing edge includes a posterior region (78) posterior to the connecting region,
The thickness (t _1B ) of the portion of the first wall located in the rear region is smaller than the thickness (t _2B ) of the portion of the second wall located in the rear region.

According to the configuration of (8) above, not only in the wall thickness reduced portion existing at least partially in the connection region, but also in the rear region located behind the connection region, the thickness of the first wall is Less than 2 wall thickness. Therefore, also in the rear region, the effect of reducing the difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be obtained. Therefore, the trailing edge portion can be cooled more effectively while suppressing the supply amount of the cooling fluid to the turbine blade, and the turbine blade can be cooled more efficiently.

(9) In some embodiments, in any of the configurations of (1) to (8) above,
In the wall thickness reduced portion, the trailing edge passage has a shape in which a width in the direction orthogonal to the camber line gradually decreases toward the trailing edge and is curved in a cross section orthogonal to the blade height direction.

According to the configuration of (9) above, in the wall thickness reduced portion, the width of the trailing edge passage gradually decreases toward the trailing edge, and the trailing edge passage has a curved shape in a cross section orthogonal to the blade height direction. Since it has, the flow velocity of the cooling fluid in the trailing edge passage can be effectively increased. As a result, the heat transfer coefficient in the trailing edge passage can be increased, and the trailing edge portion of the turbine blade can be cooled more effectively.

(10) In some embodiments, in any of the configurations of (1) to (9) above,
In the wall thickness reduced portion, the ratio t1/t2 between the thickness t1 of the first wall and the thickness t2 of the second wall is 0.5 or more and less than 1.

According to the above configuration (10), the ratio t1/t2 between the thickness t1 of the first wall and the thickness t2 of the second wall is set to 0.5 or more, so that the thickness of the blade wall is relatively thin. At the trailing edge, the thinner first wall does not become excessively thin, and the strength of the turbine blade can be secured. Further, since the above-mentioned ratio t1/t2 is less than 1, the thickness of the first wall can be made sufficiently smaller than the thickness of the second wall, and as described in (1) above. The difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be reduced. Therefore, it is possible to efficiently cool the turbine blade while appropriately securing the strength of the turbine blade.

(11) In some embodiments, in any of the configurations of (1) to (10) above,
In the wall thickness reduction portion, the wall thickness reduction rate with respect to the position change of the second wall along the camber line is greater than the wall thickness reduction rate of the first wall.

According to the above configuration (11), the wall thickness reduction rate with respect to the position change of the relatively thick second wall along the camber line is set to be larger than the wall thickness reduction rate of the relatively thin first wall. Therefore, it is easy to properly secure a relatively thin thickness of the first wall in the wall thickness reduced portion. Therefore, it is possible to efficiently cool the turbine blade while appropriately securing the strength of the turbine blade.

(12) In some embodiments, in any of the configurations of (1) to (11) above,
A cavity (60c) that extends inside the airfoil along the blade height direction on the leading edge side with respect to the trailing edge passage in the cord direction of the airfoil portion and is connected to the trailing edge passage. )When,
A pressure surface side cavity wall (74) connected to the pressure surface side wall and having an outer surface (74b) forming the pressure surface and an inner surface (74a) forming the cavity;
A suction surface side cavity wall (76) connected to the suction surface sidewall and having an outer surface (76b) forming the suction surface and an inner surface (76a) forming the cavity;
The thickness (t _1A ) of one of the pressure surface side cavity wall and the suction surface side cavity wall that is connected to the first wall is equal to the thickness of the pressure surface side cavity wall and the suction surface side cavity wall. It is smaller than one thickness (t _2A ) connected to the second wall.

From the viewpoint of improving strength, one of the pressure surface side cavity wall and the suction surface side cavity wall may be formed thicker in the cavity portion in front of the trailing edge portion. According to the configuration of (12), one of the pressure surface side cavity wall and the suction surface side cavity wall, which is relatively thin, is connected to the relatively thin first wall of the trailing edge portion, and one of which is relatively thick is the trailing edge. Connected to the relatively thick second wall of the section. In this way, since the magnitude relationship of the thickness of the blade wall on the pressure surface side and the suction surface side is made the same in the cavity portion and the wall thickness reduced portion of the trailing edge portion, it is relatively easy to manufacture the turbine blade. is there.

(13) In some embodiments, in any one of the configurations (1) to (11) above,
A cavity (60c) that extends inside the airfoil along the blade height direction on the leading edge side with respect to the trailing edge passage in the cord direction of the airfoil portion and is connected to the trailing edge passage. )When,
A pressure surface side cavity wall (74) connected to the pressure surface side wall and having an outer surface (74b) forming the pressure surface and an inner surface (74a) forming the cavity;
A suction surface side cavity wall (76) connected to the suction surface sidewall and having an outer surface (76b) forming the suction surface and an inner surface (76a) forming the cavity;
The thickness (t _1A ) of one of the pressure surface side cavity wall and the suction surface side cavity wall that is connected to the first wall is equal to the thickness of the pressure surface side cavity wall and the suction surface side cavity wall. Greater than one thickness (t _2A ) connected to the second wall.

From the viewpoint of improving strength, one of the pressure surface side cavity wall and the suction surface side cavity wall may be formed thicker in the cavity portion in front of the trailing edge portion. According to the configuration of (13), one of the pressure surface side cavity wall and the suction surface side cavity wall, which is relatively thin, is connected to the relatively thick first wall of the trailing edge portion, and one of the relatively thick one is trailing edge. Connected to a relatively thin second wall of the section. As described above, even when the dimensional relationship of the thickness of the blade wall between the pressure surface side and the suction surface side is reversed between the cavity portion and the wall thickness reduced portion of the trailing edge portion, it is described in (1) above. Thus, the difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be reduced. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade. Therefore, the turbine blade can be cooled efficiently.

(14) A gas turbine (1) according to at least one embodiment of the present invention,
The turbine blade (30) according to any one of (1) to (13) above,
A combustor (4) for producing combustion gas flowing through a combustion gas passage (28) provided with the turbine blade;
Equipped with.

According to the configuration of (14) above, in the wall thickness reduced portion of the trailing edge portion, the thickness of the first wall, which is one of the pressure surface side wall and the suction side wall, is the other of the pressure surface side wall and the suction side wall. Since the thickness of the second wall is smaller than that of the second wall, the blade wall cooling effect of the cooling fluid flowing through the trailing edge passage can be relatively increased in the thinner first wall. Therefore, even if there is a difference in the heating conditions of the blade wall between the pressure surface side and the suction surface side (such as the temperature and flow velocity of the high-temperature gas flowing near the blade surface), the above-mentioned one of the heating conditions is severe. By making the thickness of the (first wall) smaller than the thickness of the other blade wall (second wall), the difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be reduced. can do. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blade. Therefore, the turbine blade can be cooled efficiently.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a suitable combination of these forms.

In the present specification, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial". Not only represents such an arrangement strictly, but also represents a state of relative displacement or a relative displacement with an angle or a distance at which the same function can be obtained.
For example, expressions such as “identical”, “equal”, and “homogeneous” that indicate that they are in the same state are not limited to the strict equality, but also include a tolerance or a difference that provides the same function. It also indicates the existing state.
In addition, in the present specification, expressions that represent shapes such as a quadrangle and a cylinder do not only represent shapes such as a quadrangle and a cylinder in a geometrically strict sense, but also within a range in which the same effect can be obtained. A shape including an uneven portion, a chamfered portion, etc. is also shown.
Further, in this specification, the expressions “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

1 Gas Turbine 2 Compressor 4 Combustor 6 Turbine 8 Rotor 10 Compressor Cabin 12 Air Intake 16 Stator Blade 18 Blade 20 Casing 22 Turbine Cabin 24 Stator Blade 26 Blade 28 Combustion Gas Channel 28P Pressure Surface Side Area 28S Negative pressure surface side region 29 Exhaust chamber 30 Turbine blade 32 Platform 34 Airfoil portion 36 Blade root portion 37 Engagement portion 38 Base end 40 Tip end 42 Leading edge 44 Trailing edge 46 Pressure surface 48 Suction surface 50 Trailing edge portion 52 Trailing edge passage 54 Pressure Surface side wall 54a Inner surface 54b Outer surface 56 Negative pressure side wall 56a Inner surface 56b, 56b' Outer surface 58 Ribs 60, 60a to 60c Cavity 62 Film hole 64 Film hole 70 Connection region 72 Connection portion 72a Pressure surface side portion 72b Negative pressure surface side Part 73 Middle state part 74 Pressure side cavity wall 74a Inner surface 74b Outer surface 76 Negative pressure side cavity wall 76a Inner surface 76b Outer surface 78 Rear area 80 Inner end 82 Outer end 84 Inner shroud 86 Outer shroud 101 First wall 102 Second Wall 104 Wall thickness reduction area Lc Camber line

Claims (12)

A pressure surface and a suction surface extending between the leading edge and the trailing edge,
A trailing edge portion including the trailing edge and a trailing edge passage opening to the trailing edge;
A turbine blade having an airfoil portion including:
The trailing edge is
A pressure face sidewall having an outer surface forming a trailing edge region of the pressure face;
A suction surface sidewall having an outer surface that is arranged so as to face the pressure surface sidewall with the trailing edge passage interposed therebetween and has an outer surface that forms a trailing edge side region of the suction surface,
The trailing edge portion has a thickness of a first wall which is one of the pressure surface side wall and the suction side wall, and a thickness of a second wall which is the other of the pressure surface side wall and the suction side wall. Has a wall thickness decreasing portion that gradually decreases toward
Wherein the wall thickness reduction portion, wherein at any position in the coordinate axis along the camber line of the airfoil, the thickness of the first wall rather smaller than the thickness of said second wall,
The trailing edge is
A connection region that extends in the trailing edge passage and has a plurality of connection portions that are connected to the pressure surface side wall at one end side and are respectively connected to the negative pressure surface side wall at the other end side,
A rear region behind the connection region,
The wall thickness reducing portion is at least partially within the connection region,
A thickness of a portion of the first wall located in the rear region is smaller than a thickness of a portion of the second wall located in the rear region . The turbine blade according to claim 1, wherein the first wall is the suction side wall. Inside the airfoil portion, a cavity extending along the blade height direction in front of the trailing edge passage,
The turbine blade according to claim 2, wherein the airfoil portion is not provided with a film hole that is connected to the cavity and is open to the suction surface. Inside the airfoil portion, a cavity extending along the blade height direction in front of the trailing edge passage,
The turbine blade according to claim 2 or 3, wherein the airfoil portion is provided with a film hole that is connected to the cavity and opens to the pressure surface. The first wall is the pressure side wall,
Inside the airfoil portion, a cavity extending along the blade height direction in front of the trailing edge passage,
The turbine blade according to claim 1, wherein the airfoil portion is provided with a film hole that is connected to the cavity and opens to the suction surface. The first wall is the pressure side wall,
Inside the airfoil portion, a cavity extending along the blade height direction in front of the trailing edge passage,
The turbine blade according to claim 1 or 5, wherein the airfoil portion is not provided with a film hole that is connected to the cavity and is open to the pressure surface. In the wall thickness reduced portion, the trailing edge passage has a shape in which a width in a direction orthogonal to a camber line is gradually reduced toward the trailing edge and is curved in a cross section orthogonal to a blade height direction. The turbine blade according to any one of 6 above. In the wall thickness reduction portion, the ratio t1 / t2 of the thickness t2 of the first wall thickness t1 and the second wall, any one of claims 1 to 7 which is 1 less than 0.5 or more Turbine blade described in. In the wall thickness reduction portion, the wall thickness reduction rate with respect to the position variation along the camber line of the second wall, to any one of the first wall of the wall thickness reduction rate claims 1 to 8 also greater than The described turbine blade. Inside the airfoil, extending along the blade height direction on the leading edge side with respect to the trailing edge passage in the code direction of the airfoil, and a cavity connected to the trailing edge passage,
A pressure surface side cavity wall connected to the pressure surface side wall and having an outer surface forming the pressure surface and an inner surface forming the cavity;
A suction surface side cavity wall having an outer surface that is connected to the suction surface sidewall and that forms the suction surface, and a suction surface side cavity wall that has an inner surface that forms the cavity;
One of the pressure surface side cavity wall and the negative pressure surface side cavity wall, which is connected to the first wall, has a thickness that is equal to the second wall of the pressure surface side cavity wall and the negative pressure surface side cavity wall. The turbine blade according to any one of claims 1 to 9 , which is smaller than the thickness of one of the connected blades. Inside the airfoil, extending along the blade height direction on the leading edge side with respect to the trailing edge passage in the code direction of the airfoil, and a cavity connected to the trailing edge passage,
A pressure surface side cavity wall connected to the pressure surface side wall and having an outer surface forming the pressure surface and an inner surface forming the cavity;
A suction surface side cavity wall having an outer surface connected to the suction surface sidewall and forming the suction surface; and a suction surface side cavity wall having an inner surface forming the cavity,
One of the pressure surface side cavity wall and the negative pressure surface side cavity wall, which is connected to the first wall, has a thickness that is equal to the second wall of the pressure surface side cavity wall and the negative pressure surface side cavity wall. The turbine blade according to any one of claims 1 to 9 , which is thicker than the thickness of one of the connected blades. A turbine blade according to any one of claims 1 to 11 ,
A combustor for producing a combustion gas flowing through a combustion gas passage provided with the turbine blade;
Gas turbine equipped with.

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