JP2021071085A - Turbine blade and gas turbine equipped with the same - Google Patents

Abstract

To provide a turbine blade capable of efficiently cooling the turbine blade, and a gas turbine equipped with the turbine blade.SOLUTION: A turbine blade which is equipped with an airfoil portion including a pressure surface and a negative pressure surface extending between a front edge and a rear edge, and a rear edge portion including the rear edge and a rear edge passage opening to the rear edge. The rear edge portion includes a pressure surface side wall having an outer surface forming a rear edge area of the pressure surface, and a negative pressure surface side wall arranged so as to oppose the pressure surface side wall with the rear edge passage therebetween and having an outer surface forming a rear edge side area of the negative pressure surface. The rear edge portion has a wall thickness decreasing portion in which the thickness of a first wall that is one of the pressure surface side wall or the negative pressure surface side wall and the thickness of a second wall that is the other of the pressure surface side wall or the negative pressure side wall gradually decreases toward the rear edge. In the wall thickness decreasing portion, at an optional position in a coordinate axis along a camber line of the airfoil portion, the thickness of the first wall is smaller than that of the second wall.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to turbine blades and gas turbines equipped thereto.

It is known that in a turbine blade such as a gas turbine, the turbine blade exposed to a high temperature gas flow is cooled 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 of the turbine blade is provided with a trailing edge passage that is connected to the above-mentioned cavity and opens to the trailing edge, and the trailing edge of the turbine blade is cooled by a cooling fluid flowing through the trailing edge passage. It has become so.

Japanese Unexamined Patent Publication No. 9-144503

By the way, the turbine blade has an allowable metal temperature according to 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 so as to be equal to or lower than the allowable metal temperature.

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 (ventral side) and the negative pressure surface side (dorsal side) of the turbine blade. In this way, when the heating conditions of the blade wall differ between the pressure surface side and the negative pressure surface side of the turbine blade, the blade wall thickness on the pressure surface side and the blade wall thickness on the negative pressure surface side at the trailing edge are the same. The metal temperature on the blade surface (hereinafter, also referred to as the surface metal temperature) is higher on one of the pressure surface side and the negative pressure surface side, where the above-mentioned heating conditions are severe, as compared with the other.

On the other hand, in order to keep both the blade wall on the pressure surface side and the blade wall on the negative pressure surface side below the permissible temperature, it is necessary for the surface metal temperature of the blade wall having the higher surface metal temperature to be below the permissible metal temperature. It is necessary to supply a large amount of cooling fluid to the trailing edge passage 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, until it becomes lower than the allowable metal temperature). In this case, an excessive amount of cooling fluid is supplied to the blade wall having a 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 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.

The turbine blade according to at least one embodiment of the present invention is
A pressure surface and a negative pressure surface extending between the front edge and the trailing edge,
A trailing edge including the trailing edge and a trailing edge passage that opens into the trailing edge, and
A turbine blade with an airfoil that includes
The trailing edge
A pressure surface side wall having an outer surface forming a trailing edge side region of the pressure surface,
Includes a negative pressure surface side wall that is arranged to face the pressure surface side wall across the trailing edge passage and has an outer surface that forms a trailing edge side region of the negative pressure surface.
The trailing edge is the thickness of the first wall which is one of the pressure surface side wall or the negative pressure surface side wall, and the thickness of the second wall which is the other of the pressure surface side wall or the negative pressure surface side wall. It has a wall thickness reduction part that gradually decreases toward
In the wall thickness reducing 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 of the airfoil portion.

Further, the gas turbine according to at least one embodiment of the present invention is
With the turbine blades mentioned above,
A combustor for generating combustion gas flowing through a combustion gas flow path provided with the turbine blades, and a combustor.
To be equipped.

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

It is a schematic block diagram of the gas turbine to which the turbine blade which concerns on one Embodiment is applied. It is the schematic which looked at the turbine blade (moving blade) which concerns on one Embodiment in the direction from the pressure plane toward the negative pressure plane (the direction along the rotor circumferential direction). It is a schematic sectional view of the turbine blade which concerns on one Embodiment, and corresponds to the sectional view taken along the arrow AA of FIG. It is a schematic sectional view of the turbine blade which concerns on one Embodiment, and corresponds to the sectional view taken along the arrow AA of FIG. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the trailing edge of the turbine blade shown in FIG. It is a schematic sectional view of the turbine blade which concerns on one Embodiment, and is the enlarged sectional view which shows the vicinity of the trailing edge portion of the turbine blade. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the trailing edge of the turbine blade shown in FIG. It is a schematic diagram which superimposes the cross section of the trailing edge portion of the turbine blade installed in a gas turbine, and the temperature distribution in this cross section. It is the schematic which looked at the turbine blade (static blade) which concerns on one Embodiment in the direction from the pressure plane toward the negative pressure plane (the direction along the rotor circumferential direction).

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

(Composition of gas turbine)
First, a gas turbine to which the 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, the gas turbine 1 is rotationally driven by a compressor 2 for generating compressed air, a combustor 4 for generating combustion gas using compressed air and fuel, and a combustion gas. A turbine 6 configured as described above is provided. In the case of the gas turbine 1 for power generation, a generator (not shown) is connected to the turbine 6.

The compressor 2 includes a plurality of stationary blades 16 fixed to the compressor cabin 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. .. 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 to achieve high temperature and high pressure. It becomes compressed air.

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

The turbine 6 has a combustion gas flow path 28 formed in the turbine casing 22, and includes a plurality of stationary blades 24 and moving blades 26 provided in the combustion gas flow path 28. The stationary blades 24 are fixed to the turbine casing 22 side, and a plurality of stationary blades 24 arranged along the circumferential direction of the rotor 8 form a stationary blade row. Further, the moving blades 26 are planted in the rotor 8, and a 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 flow path 28 passes through the plurality of stationary blades 24 and the plurality of moving blades 26 to rotationally drive the rotor 8 and thereby connect to the rotor 8. The generated generator is driven to generate electric power. The combustion gas after driving the turbine 6 is discharged to the outside through the exhaust chamber 29.

In some embodiments, at least one of the rotor blades 26 or the stationary blades 24 of the turbine 6 is the turbine blades 30 described below.

(Construction of turbine blades)
Hereinafter, the turbine blades 30 according to some embodiments will be described in more detail. 2 and 9 are schematic views of the turbine blades 30 according to the embodiment as viewed in the direction from the pressure surface to the negative pressure surface (direction along the circumferential direction of the rotor), respectively. Of these, FIG. 2 is a diagram showing a moving blade 26 as a turbine blade 30, and FIG. 9 is a diagram showing a stationary blade 24 as a 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, respectively, and correspond to the cross-sectional view 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 base ends 38 and tips 40 which 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 front edge 42 and a trailing edge 44 extending along the blade height direction, and also has a pressure surface 46 and a negative pressure surface 48 extending between the front edge 42 and the trailing edge 44. ..

The blade root portion 36 is located on the side opposite to 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 a concave-convex 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, whereby the turbine blade 30 Is attached to the rotor 8 of the turbine 6.

As shown in FIG. 9, the turbine blade 30 (static blade 24) according to the embodiment has an airfoil portion 34, an inner shroud 84 located radially inside the airfoil portion 34, and an airfoil portion 34. It includes an outer shroud 86 located on the outer side in the radial direction with respect to the airfoil 86. The outer shroud 86 is supported by the turbine casing 22 (see FIG. 1), and the vane 24 is supported by the turbine carriage 22 via the outer shroud 86.

The airfoil portion 34 extends in the blade height direction (span direction), has inner ends 80 and outer ends 82 which are both ends in the blade height direction, and is connected to the inner shroud 84 on the inner end 80 side. At the same time, it is connected to the outer shroud 86 on the outer end 82 side. Further, the airfoil portion 34 has a front edge 42 and a trailing edge 44 extending along the blade height direction, and also has a pressure surface 46 and a negative pressure surface 48 extending between the front edge 42 and the trailing edge 44. ..

When the turbine blade 30 (moving blade 26) is attached to the rotor 8 or the turbine blade 30 (static blade 24) is supported by the turbine cabin 22, the blade height direction is 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 coincide with each other.

In the following, the turbine blade 30 will be described with reference to the diagram 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 has a plurality of cavities 60a, 60b, 60c (hereinafter collectively referred to as cavities 60) extending along the blade height direction at least inside the airfoil portion 34. It has.). In the exemplary embodiment shown in FIGS. 3 and 4, ribs 58 extending along the airfoil height direction to partition the internal space of the airfoil portion 34 are provided between adjacent cavities 60, and the airfoil 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).
In the exemplary embodiment shown in FIGS. 3 and 4, three cavities 60 are provided inside the airfoil portion 34, but the number of cavities provided in the airfoil portion 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 portion 34 is provided with film holes 62, 64 that are connected to the cavity 60 and open into the pressure surface 46 or the negative pressure surface 48. A part of the cooling fluid flowing through the cavity 60 is guided to the outer wall surface (pressure surface 46 or negative pressure surface 48) of the turbine blade 30 through the film holes 62 and 64 to form 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 portion 34 is provided with a film hole 62 that is connected to the cavity 60 and opens to the negative pressure surface 48. Further, in the exemplary embodiment shown in FIG. 4, the airfoil portion 34 is provided with a film hole 64 which is connected to the cavity 60 and opens in the pressure surface 46.

The airfoil portion 34 has a trailing edge portion 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 front edge side of the cavity 60 in the cord direction of the airfoil portion 34, and is connected to the cavity 60 (cavity 60c in the illustrated example) inside the airfoil portion 34.

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

Further, the trailing edge portion 50 has a wall thickness reducing portion 104 in which the thicknesses of the pressure surface side wall 54 and the negative pressure surface side wall 56 gradually decrease 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 negative pressure surface side wall 56 is the thickness in the direction orthogonal to the camber line Lc of the airfoil portion 34.

Then, in the wall thickness reducing portion 104, the thickness of the first wall 101, which is one of the pressure surface side wall 54 or the negative pressure surface side wall 56, is the pressure at an arbitrary position on the coordinate axis along the camber line Lc of the airfoil portion 34. It is smaller than the thickness of the second wall 102, which is the other side of the surface side wall 54 or the negative pressure surface side wall 56. That is, the wall thickness reduction unit 104, the thickness t1 of the first wall 101 along a straight line _{L P} (see FIGS. 5 to 7) perpendicular 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 embodiment shown in FIGS. 3, 5 and 6, in the wall thickness reducing portion 104, the thickness t1 of the pressure surface side wall 54 as the first wall 101 is the negative pressure 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 reducing portion 104, the thickness t1 of the negative pressure surface side wall 56 as the first wall 101 is the thickness t1 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 view 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, the turbine blades 30 arranged in the combustion gas flow path 28 in the gas turbine 1 have a pressure surface 46 facing the pressure surface side region 28P of the combustion gas flow path 28 and a negative pressure surface. 48 faces the negative pressure surface side region 28S of the combustion gas flow path 28.
In FIG. 8, the outer surface of the negative pressure surface side wall 56 when the thickness of the pressure surface side wall 54 and the negative pressure surface side wall 56 is assumed to be the same is shown by a broken line and reference numeral 56b'. The temperature T _A indicated by a chain line in the drawing, the allowable metal temperature of the turbine blade 30.

In the following, a case where the heating conditions of the blade wall are stricter on the negative pressure surface 48 side than on the pressure surface 46 side will be described with reference to FIG. 8, but the pressure surface 46 side is described as compared with the negative pressure surface 48 side. The case where the heating conditions of the above are more severe can be similarly explained by appropriately replacing the pressure surface 46 and the negative pressure surface 48 in the following description.

The heating conditions of the blade wall including the temperature and flow velocity of the high-temperature gas flowing in the vicinity of the blade surface may differ between the pressure surface 46 side and the negative pressure surface 48 side of the turbine blade 30. In the example shown in FIG. 8, the gas temperature T _S at the suction side region 28S of the combustion gas flow passage 28 suction side 48 faces, the gas in the pressure surface side region 28P of the combustion gas flow passage 28 in which the pressure surface 46 facing higher than the temperature T _P, i.e., more severe heating conditions of the turbine blade 30 is at the negative pressure surface 48 side. 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 that the heating conditions become more severe.

Under the above conditions, if the thickness of the pressure surface side wall 54 and the negative pressure surface side wall 56 are the same (in this case, the outer surface 56b'of the negative pressure surface side wall 56), the metal temperature of the pressure surface side wall 54 is allowed to be the allowable temperature. to reduce to TA (i.e., to lower the metal temperature of the outer surface 54b which is the highest metal temperature of the pressure surface side wall 54 to an acceptable temperature TA), the cooling fluid temperature T _C which is necessary to supply the trailing edge passage 52 The supply amount of is V ₀ .

In this case, the difference between the temperature T _C of the blade wall (the pressure face side walls 54 and suction side sidewall 56) the temperature of the hot gas is a fluid of the outer surface (T _P or T _S) and a fluid on the inner surface side cooling 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 on the negative pressure surface side wall 56 than on the pressure surface side wall 54. Then, the metal temperature of the outer surface 56b 'which is the highest metal temperature of the suction side sidewall 56 (the surface metal temperature), it becomes high temperature T _Q than the allowable temperature T _A.

Increase In order to make the surface metal temperature of the suction side sidewall 56 below the allowable temperature T _A with the cooling fluid temperature Tc, the supply amount of the cooling fluid to the trailing edge passage 52 than V ₀ which above I need to let you. However, when the supply amount of the cooling fluid is increased in this way, the pressure surface side wall 54 whose heating conditions are relatively gentle is further cooled and the temperature is lowered, and the metal temperature (surface metal temperature) of the outer surface 54b is changed. lower than the allowable temperature _{T A.} In this case, an excessive amount of cooling fluid is supplied to the pressure surface side wall 54.

In this regard, according to the above-described embodiment, in the wall thickness reducing portion 104 of the trailing edge portion 50, the first wall 101 which is one of the pressure surface side wall 54 or the negative pressure surface side wall 56 (negative pressure surface side wall 56 in FIG. 8). Since the thickness t1 was made smaller than the thickness t2 of the second wall 102, which is the other side of the pressure surface side wall 54 or the negative pressure surface side wall 56 (pressure surface side wall 54 in FIG. 8), the thickness t1 was made smaller than the thickness t2 of the second wall 102. The effect of cooling the blade wall by 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 (negative pressure surface side wall 56), the supply amount of the cooling fluid to the trailing edge passage 52 remains _{V 0 as described above.} in (i.e., without increasing the supply amount of the cooling fluid), it is possible to lower the metal temperature (surface metal temperature) in the outer surface 56b to an acceptable 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 (temperature, flow velocity, etc. of the high temperature gas flowing near the blade surface) between the pressure surface 46 side and the negative pressure surface 48 side, the above heating conditions are severe. By making the thickness of one blade wall (first wall 101) thinner than the thickness of the other blade wall (second wall 102), the first wall 101 and the second wall 102 are cooled by the cooling fluid. The difference in 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 blades 30. Therefore, the turbine blade 30 can be cooled efficiently.

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

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 when the cooling of the outer surface of the turbine blade 30 (for example, film cooling by the cooling fluid from the film hole) is not taken into consideration. Tighter in. In this respect, according to the above-described embodiment, the negative pressure surface side wall 56 (first wall 101), which is the blade wall on the negative pressure surface 48 side where the heating conditions are stricter, 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 blades 30, and therefore, the turbine blades 30 can be efficiently cooled.

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

By installing a film hole that opens in the blade surface of the turbine blade 30, the temperature of the blade surface on the downstream side (that is, the trailing edge 44 side in the cord direction) of the film hole is lowered by the cooling fluid flowing out from the film hole. That is, by installing the film holes in front of the trailing edge portion 50, the heating conditions of the turbine blades 30 at the trailing edge portion 50 are relaxed.
In this respect, in the above-described embodiment, the film hole connected to the cavity 60 located in front of the trailing edge passage 52 and opened in the negative pressure surface 48 is not provided. Therefore, usually, on the negative pressure surface 48 side where the heating conditions of the turbine blades 30 are stricter, the effect of relaxing the heating conditions by installing such film holes cannot be obtained. Under such a situation, in the above-described embodiment, as described above, the negative pressure surface side wall 56 (first wall 101), which is the blade wall on the negative pressure surface 48 side, is replaced with 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 blades 30, and therefore the turbine blades 30 can be efficiently cooled.

In the present specification, the front is the direction from the trailing edge 44 to the front edge 42 in the chord direction of the airfoil portion 34, and the rear is the direction from the front edge 42 to the trailing edge in the chord direction of the airfoil portion 34. The direction is toward 44.

In the exemplary embodiment shown in FIGS. 4 and 7, the airfoil portion 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 into the pressure surface 46. There is.

In the above-described embodiment, a film hole 64 is provided which is connected to the cavity 60 located in front of the trailing edge passage 52 and opens in the pressure surface 46. Therefore, usually, on the pressure surface 46 side where the heating conditions of the turbine blades 30 are more lenient, the heating conditions are relaxed by installing the film holes 64, so that the heating conditions are relatively stricter on the negative pressure surface 48 side.
In this respect, in the above-described embodiment, as described above, the negative pressure surface side wall 56 (first wall 101), which is the blade wall on the negative pressure 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 blades 30, and therefore the turbine blades 30 can be efficiently cooled.

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

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

In the above-described embodiment, a film hole 62 is provided which is connected to the cavity 60 located in front of the trailing edge passage 52 and opens in the negative pressure surface 48. Therefore, normally, the heating condition is relaxed by installing the film hole 62 on the negative pressure surface 48 side where the heating condition of the turbine blade 30 is stricter, but for this reason, the heating condition is relatively stricter on the pressure surface 46 side. Become.
In this respect, 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), so that it 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 blades 30, and therefore the turbine blades 30 can be efficiently cooled.

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

In the above-described embodiment, the film hole connected to the cavity 60 located in front of the trailing edge passage 52 and opened in the pressure surface 46 is not provided. Therefore, on the pressure surface 46 side, the effect of relaxing the heating conditions by installing the film holes 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 negative pressure surface side wall 56 (second wall 102). For example, when the heating conditions on the negative pressure surface 48 side of the trailing edge 50 are relatively gentle due to the provision of film holes 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 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 blades 30, and therefore the turbine blades 30 can be efficiently cooled.

In some embodiments, for example, as shown in FIGS. 3-7, the trailing edge 50 includes a connection area 70 in which a plurality of connections 72 are provided. Each of the plurality of connecting portions 72 extends to the trailing edge passage 52, is connected to the pressure surface side wall 54 on one end side, and is connected to the negative pressure surface side wall 56 on the other end side. The wall thickness reduction portion 104 is at least partially present in the connection region 70.
In FIGS. 5 to 7, the connection region 70 is the straight line L1 indicating the position of the connection portion 72 located on the front edge 42 side of the plurality of connection portions 72 in the direction along the camber line Lc. It extends between the 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 a relatively thin wall thickness and a relatively low strength is provided at least partially in the connection region 70, it is connected to the pressure surface side wall 54 and the negative pressure surface side wall 56. The connecting portion 72 formed can supplement the strength of the turbine blade 30 in the wall thickness reducing 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 is provided inside the trailing edge passage 52 via a sandbar 73 provided between the pressure surface side wall 54 and the negative pressure surface side wall 56. It may be connected to the pressure surface side wall 54 and the negative pressure surface side wall 56. The connection portion 72 is connected to the pressure surface side wall 54 on one end side and to the pressure surface side portion 72a connected to the Nakasu portion 73 on the other end side, and to the negative pressure surface side wall 56 on one end side. At the other end, the negative pressure surface side portion 72b connected to the sandbar portion 73 may be included.

In some embodiments, the connection 72 may be a pin fin extending 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 (ie, the entire region between straight lines L1 and L2 in the camber line Lc direction in FIGS. 5-7) is included in the wall thickness reduction portion 104. May be good.

In some embodiments, the trailing edge 50 includes a posterior region 78 posterior to the contiguous zone 70. In FIGS. 5 to 7, the rear region 78 is a region 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 not only in the wall thickness reducing portion 104 existing in the connection region 70 but also in the rear region 78 located behind the connection region 70. It is smaller than the thickness t2 of the two walls 102. Therefore, even in the rear region 78, 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 can be obtained. Therefore, the trailing edge portion 50 can be cooled more effectively while suppressing the supply amount of the cooling fluid to the turbine blades 30, and the turbine blades 30 can be cooled more efficiently.

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

According to the above-described embodiment, in the wall thickness reducing 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 a shaped shape, the flow velocity of the cooling fluid in the trailing edge passage 52 can be effectively increased. As a result, 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 reducing portion 104, the ratio t1 / t2 of the thickness t1 of the first wall 101 to 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 to the thickness t2 of the second wall 102 is 0.5 or more, the thickness of the blade wall is relatively thin. At the edge 50, the thinner first wall 101 is not excessively thinned, and the strength of the turbine blade 30 can be ensured. Further, since the above-mentioned ratio t1 / t2 is set to less than 1, the thickness of the first wall 101 can be made sufficiently thinner than the thickness of the second wall 102, whereby the cooling fluid cools the first wall 101. The difference in surface metal temperature between the first wall 101 and the second wall 102 can be reduced. Therefore, the turbine blades can be efficiently cooled while ensuring the appropriate strength of the turbine blades 30.

In some embodiments, in the wall thickness reduction portion 104, the wall thickness reduction rate with respect to the position change of the second wall 102 along the camber line Lc is larger 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 along the camber line Lc of the relatively thick second wall 102 is made larger than the wall thickness reduction rate of the relatively thin first wall 101. Therefore, it is easy to appropriately secure the thickness of the relatively thin first wall 101 in the wall thickness reducing portion 104. Therefore, the turbine blades 30 can be efficiently cooled while ensuring the appropriate strength of the turbine blades 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 negative pressure surface side cavity wall 76 connected to the negative pressure 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 the cavity 60c connected to the trailing edge passage 52. The negative pressure surface side cavity wall 76 connected to the negative pressure surface side wall 56 has an outer surface 76b forming the negative pressure surface 48 and an inner surface 76a forming the cavity 60c connected to the trailing edge passage 52.

In some embodiments, the thickness of one of the pressure surface side cavity wall 74 and the negative pressure surface side cavity wall 76 connected to the first wall 101 is the pressure surface side cavity wall 74 and the negative pressure surface side cavity wall 76. It is smaller than the thickness of one connected to the second wall 102.
_{For example, in the exemplary embodiment shown in FIG. 3, the thickness t 1A} of the pressure surface side cavity wall 74 connected to the pressure surface side wall 54 which is the first wall 101 is the negative pressure surface side wall 56 which is the second wall 102. _{It is smaller than the thickness t 2A of the} negative pressure surface side cavity wall 76 connected to (see FIGS. 5 and 6).

In the cavity portion in front of the trailing edge portion 50, one of the pressure surface side cavity wall 74 and the negative pressure surface side cavity wall 76 may be formed thick from the viewpoint of improving the strength. In the exemplary embodiment shown in FIG. 3, the negative pressure surface side cavity wall 76 is formed to be relatively thick. In this regard, according to the above-described embodiment, of the pressure surface side cavity wall 74 or the negative pressure surface side cavity wall 76, one of the relatively thin ones (the pressure surface side cavity wall 74 in the example of FIG. 3) is the trailing edge portion 50. It is connected to a relatively thin first wall 101, and one relatively thick (negative pressure surface side cavity wall 76 in the example of FIG. 3) is connected to a relatively thick second wall 102 of the trailing edge portion 50. In this way, the magnitude relationship between the thickness of the blade wall between the pressure surface 46 side and the negative pressure surface 48 side is the same for the cavity portion and the wall thickness reduction portion 104 of the trailing edge portion 50, so that the turbine blade 30 is manufactured. Is relatively easy.

In some embodiments, the thickness of one of the pressure surface side cavity wall 74 and the negative pressure surface side cavity wall 76 connected to the first wall 101 is the pressure surface side cavity wall 74 and the negative pressure surface side cavity wall 76. It is larger than the thickness of one connected to the second wall 102.
_{For example, in the exemplary embodiment shown in FIG. 4, the thickness t 1A} of the negative pressure surface side cavity wall 76 connected to the negative pressure surface side wall 56 which is the first wall 101 is the pressure surface side wall 54 which is the second wall 102. _{It 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 negative pressure surface side cavity wall 76 may be formed thick from the viewpoint of improving the strength. In the exemplary embodiment shown in FIG. 4, the negative pressure surface side cavity wall 76 is formed to be relatively thick. In this regard, according to the above-described embodiment, of the pressure surface side cavity wall 74 or the negative pressure surface side cavity wall 76, one of the relatively thin ones (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 (negative pressure surface side cavity wall 76 in the example of FIG. 4) is connected to the relatively thin second wall 102 of the trailing edge portion 50. In this way, even when the magnitude relationship between the thickness of the blade wall between the pressure surface 46 side and the negative pressure surface 48 side is reversed between the cavity portion and the wall thickness reduction portion 104 of the trailing edge portion 50, the above-mentioned wall By providing the thickness reducing portion 104, the difference in surface metal temperature between the first wall 101 and the 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 blades 30. Therefore, the turbine blade 30 can be cooled efficiently.

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

(1) The turbine blade (30) according to at least one embodiment of the present invention is
A pressure surface (46) and a negative pressure surface (48) extending between the front edge (42) and the trailing edge (44),
A trailing edge portion (50) including the trailing edge and a trailing edge passage (52) that opens into the trailing edge.
A turbine blade having an airfoil portion (34) including.
The trailing edge
A pressure surface side wall (54) having an outer surface (54b) forming a trailing edge side region of the pressure surface,
A negative pressure surface side wall (56), which is arranged so as to face the pressure surface side wall across the trailing edge passage and has an outer surface (56b) forming a trailing edge side region of the negative pressure surface, is included.
The trailing edge portion has a thickness (t1) of a first wall (101) which is one of the pressure surface side wall or the negative pressure surface side wall, and a second wall which is the other of the pressure surface side wall or the negative pressure surface side wall. It has a wall thickness reduction portion (104) in which the thickness (t2) of (102) gradually decreases toward the trailing edge.
In the wall thickness reducing 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 configuration of (1) above, in the wall thickness reduction portion of the trailing edge portion, the thickness of the first wall which is one of the pressure surface side wall or the negative pressure surface side wall is set to the other of the pressure surface side wall or the negative pressure surface side wall. Since it is made smaller than the thickness of the second wall, the wing wall cooling effect by the cooling fluid flowing through the trailing edge passage can be relatively enhanced in the thinner first wall. Therefore, even if there is a difference in the heating conditions of the blade wall (temperature, flow velocity, etc. of the high-temperature gas flowing near the blade surface) between the pressure surface side and the negative pressure surface side, one of the blade walls where the above heating conditions are severe is severe. By making the thickness of (first wall) thinner 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 is reduced. can do. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blades. Therefore, the turbine blades can be cooled efficiently.

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

The heating conditions of the turbine blades by the high temperature gas are usually stricter on the negative pressure surface side than on the pressure surface side. In this respect, according to the configuration of (2) above, the negative pressure surface side wall (first wall), which is the blade wall on the negative pressure surface side where the heating conditions are stricter, is made thinner than the pressure surface side wall (second wall). 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 portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blades, and therefore the turbine blades can be efficiently cooled.

(3) In some embodiments, in the configuration of (2) above,
Inside the airfoil, 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 negative pressure surface.

By installing a film hole that opens in 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 is lowered by the cooling fluid flowing out from the film hole. That is, by installing the film holes in front of the trailing edge portion, the heating conditions of the turbine blades at the trailing edge portion are relaxed.
In this respect, in the configuration of (3) above, the film hole connected to the cavity located in front of the trailing edge passage and opened in the negative pressure surface is not provided. Therefore, usually, on the negative pressure surface side where the heating conditions of the turbine blades are stricter, the effect of relaxing the heating conditions by installing such film holes cannot be obtained. Under such circumstances, in the configuration of (3) above, as described in (2) above, the negative pressure surface side wall (first wall), which is the blade wall on the negative pressure surface side, is replaced with the pressure surface side wall (second wall). ), 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 portion can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blades, and therefore the turbine blades can be efficiently cooled.

(4) In some embodiments, in the configuration of (2) or (3) above,
Inside the airfoil, a cavity (60a, 60b, 60c) extending along the blade height direction in front of the trailing edge passage is provided.
The airfoil portion is provided with a film hole (64) connected to the cavity and opened 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 in the pressure surface. Therefore, usually, on the pressure surface side where the heating conditions of the turbine blades are more lenient, the heating conditions are relaxed by installing the film holes, so that the heating conditions are relatively stricter on the negative pressure surface side.
In this regard, in the configuration of (4) above, as described in (2) above, the negative pressure surface side wall (first wall), which is the blade wall on the negative pressure 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 portion can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blades, and therefore the turbine blades can be efficiently cooled.

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

In the configuration of (5) above, a 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, the heating condition is relaxed by installing the film holes on the negative pressure surface side where the heating condition of the turbine blade is stricter, but for this reason, the heating condition becomes relatively stricter on the pressure surface side.
In this regard, in the configuration of (5) above, the pressure surface side wall (first wall), which is the blade wall on the pressure surface side, is made thinner than the negative pressure surface side wall (second wall), so that the pressure cooled by the cooling fluid is obtained. The difference in surface metal temperature between the surface side wall (first wall) and the negative pressure surface side wall (second wall) can be reduced. Therefore, the trailing edge portion can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blades, and therefore the turbine blades can be efficiently cooled.

(6) In some embodiments, in the configuration of (1) or (5) above,
The first wall is the side wall of the pressure surface and
Inside the airfoil, 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 pressure surface.

In the configuration of (6) above, the film hole connected to the cavity located in front of the trailing edge passage and opened in the pressure surface is not provided. Therefore, on the pressure surface side, the effect of relaxing the heating conditions by installing the film holes cannot be obtained.
Under such a situation, in the configuration (6) above, the pressure surface side wall (first wall), which is the blade wall on the pressure surface side, is made thinner than the negative pressure surface side wall (second wall). Pressure surface side wall (first wall) cooled by the cooling fluid when the heating conditions on the negative pressure surface side at the trailing edge are relatively gentle due to the provision of film holes on the side, etc. The difference between the surface metal temperature of the negative pressure surface side wall (second wall) and the surface metal temperature of the negative pressure surface side wall (second wall) can be reduced. Therefore, the trailing edge portion can be appropriately cooled while effectively suppressing the supply amount of the cooling fluid to the turbine blades, and therefore the turbine blades can be efficiently cooled.

(7) In some embodiments, in any of the configurations (1) to (6) above,
The trailing edge portion extends into the trailing edge passage, and is provided with a plurality of connecting portions (72) connected to the pressure surface side wall on one end side and connected to the negative pressure surface side wall on the other end side. Containing the connection area (70) to be
The wall thickness reduction portion is at least partially present in the continental zone.

According to the configuration of (7) above, since the wall thickness reducing portion having a relatively thin wall thickness and a relatively low strength is provided at least partially in the connection region, it is connected to the pressure surface side wall and the negative pressure surface side wall. The connection can supplement the strength of the turbine blades at the wall thickness reduction. Therefore, the turbine blades can be efficiently cooled while ensuring the strength of the turbine blades.

(8) In some embodiments, in the configuration of (7) above,
The trailing edge includes a posterior region (78) posterior to the contiguous zone.
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, the thickness of the first wall is the first not only in the wall thickness reducing portion existing in the connection region at least partially, but also in the rear region located behind the connection region. 2 Less than the wall thickness. Therefore, even 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 blades, and the turbine blades can be cooled more efficiently.

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

According to the configuration of (9) above, in the wall thickness reduction portion, the width of the trailing edge passage gradually decreases toward the trailing edge, and the trailing edge passage is curved in a cross section orthogonal to the blade height direction. Therefore, 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 (1) to (9) above,
In the wall thickness reducing portion, the ratio t1 / t2 of 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 configuration of (10) above, the ratio t1 / t2 of the thickness t1 of the first wall to 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 is not excessively thinned, and the strength of the turbine blade can be ensured. Further, since the above-mentioned ratio t1 / t2 is set to less than 1, the thickness of the first wall can be made sufficiently thinner than the thickness of the second wall, and as described in the above (1), The difference in surface metal temperature between the first wall and the second wall cooled by the cooling fluid can be reduced. Therefore, the turbine blades can be efficiently cooled while ensuring the appropriate strength of the turbine blades.

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

According to the configuration of (11) above, the wall thickness reduction rate with respect to the position change along the camber line of the relatively thick second wall is made larger than the wall thickness reduction rate of the relatively thin first wall. Therefore, it is easy to appropriately secure a relatively thin thickness of the first wall in the wall thickness reducing portion. Therefore, the turbine blades can be efficiently cooled while ensuring the appropriate strength of the turbine blades.

(12) In some embodiments, in any of the configurations (1) to (11) above,
Inside the airfoil portion, a cavity (60c) extending along the blade height direction on the front edge side of the trailing edge passage in the cord direction of the airfoil portion and 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 negative pressure surface side cavity wall (76) connected to the negative pressure surface side wall and having an outer surface (76b) forming the negative pressure surface and an inner surface (76a) forming the cavity is provided.
_{The thickness (t 1A} ) of one of the pressure surface side cavity wall and the negative pressure surface side cavity wall connected to the first wall is the thickness (t 1A) of the pressure surface side cavity wall and the negative pressure surface side cavity wall. It is smaller than _{the thickness (t 2A} ) of one connected to the second wall.

In the cavity portion in front of the trailing edge portion, one of the pressure surface side cavity wall and the negative pressure surface side cavity wall may be formed thick from the viewpoint of improving the strength. According to the configuration of (12) above, of the pressure surface side cavity wall or the negative pressure surface side cavity wall, one relatively thin is connected to the relatively thin first wall at the trailing edge, and the relatively thick one is connected to the trailing edge. It is connected to the relatively thick second wall of the part. In this way, the magnitude relationship between the thickness of the blade wall on the pressure surface side and the negative pressure surface side is the same for the cavity portion and the wall thickness reduction portion at the trailing edge, so it is relatively easy to manufacture turbine blades. is there.

(13) In some embodiments, in any of the configurations (1) to (11) above,
Inside the airfoil portion, a cavity (60c) extending along the blade height direction on the front edge side of the trailing edge passage in the cord direction of the airfoil portion and 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 negative pressure surface side cavity wall (76) connected to the negative pressure surface side wall and having an outer surface (76b) forming the negative pressure surface and an inner surface (76a) forming the cavity is provided.
_{The thickness (t 1A} ) of one of the pressure surface side cavity wall and the negative pressure surface side cavity wall connected to the first wall is the thickness (t 1A) of the pressure surface side cavity wall and the negative pressure surface side cavity wall. It is larger than _{the thickness (t 2A} ) of one connected to the second wall.

In the cavity portion in front of the trailing edge portion, one of the pressure surface side cavity wall and the negative pressure surface side cavity wall may be formed thick from the viewpoint of improving the strength. According to the configuration of (13) above, one of the relatively thin cavity wall on the pressure surface side or the cavity wall on the negative pressure surface side is connected to the relatively thick first wall at the trailing edge, and the relatively thick one is connected to the trailing edge. It is connected to the relatively thin second wall of the part. As described above, even when the magnitude relationship of the thickness of the blade wall between the pressure surface side and the negative pressure surface side is reversed between the cavity portion and the wall thickness reduction portion of the trailing edge portion, it is described in (1) above. As described above, 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 blades. Therefore, the turbine blades can be cooled efficiently.

(14) The gas turbine (1) according to at least one embodiment of the present invention is
The turbine blade (30) according to any one of (1) to (13) above, and
A combustor (4) for generating combustion gas flowing through a combustion gas flow path (28) provided with the turbine blades, and a combustor (4).
To be equipped.

According to the configuration of (14) above, in the wall thickness reduction portion of the trailing edge portion, the thickness of the first wall, which is one of the pressure surface side wall or the negative pressure surface side wall, is set to the other of the pressure surface side wall or the negative pressure surface side wall. Since it is made smaller than the thickness of the second wall, the wing wall cooling effect by the cooling fluid flowing through the trailing edge passage can be relatively enhanced in the thinner first wall. Therefore, even if there is a difference in the heating conditions of the blade wall (temperature, flow velocity, etc. of the high-temperature gas flowing near the blade surface) between the pressure surface side and the negative pressure surface side, one of the blade walls where the above heating conditions are severe is severe. By making the thickness of (first wall) thinner 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 is reduced. can do. Therefore, the trailing edge portion can be appropriately cooled while suppressing the supply amount of the cooling fluid to the turbine blades. Therefore, the turbine blades can be cooled efficiently.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes a modified form of the above-described embodiments and a combination of these embodiments as appropriate.

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". Strictly represents not only such an arrangement, but also a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
Further, in the present specification, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also within a range in which the same effect can be obtained. , The shape including the uneven portion, the chamfered portion, etc. shall also be represented.
Further, in the present specification, the expression "comprising", "including", or "having" one component is not an exclusive expression excluding the existence of another component.

1 Gas turbine 2 Compressor 4 Combustor 6 Turbine 8 Rotor 10 Compressor cabin 12 Air intake 16 Static blade 18 Moving blade 20 Casing 22 Turbine cabin 24 Static blade 26 Moving blade 28 Combustion gas flow path 28P Pressure surface side region 28S Negative pressure surface side area 29 Exhaust chamber 30 Turbine blade 32 Platform 34 Blade shape 36 Blade root 37 Engagement 38 Base end 40 Tip 42 Front edge 44 Trailing edge 46 Pressure surface 48 Negative pressure surface 50 Trailing edge 52 Trailing edge passage 54 Pressure Surface side wall 54a Inner surface 54b Outer surface 56 Negative pressure surface side wall 56a Inner surface 56b, 56b'Outer surface 58 Ribs 60, 60a to 60c Cavity 62 Film hole 64 Film hole 70 Connection area 72 Connection part 72a Pressure surface side portion 72b Negative pressure surface side Part 73 Chushu 74 Pressure surface side cavity wall 74a Inner surface 74b Outer surface 76 Negative pressure surface 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 part Lc camber line

The turbine blade according to at least one embodiment of the present invention is
A pressure surface and a negative pressure surface extending between the front edge and the trailing edge,
A trailing edge including the trailing edge and a trailing edge passage that opens into the trailing edge, and
A turbine blade with an airfoil that includes
The trailing edge
A pressure surface side wall having an outer surface forming a trailing edge side region of the pressure surface,
Includes a negative pressure surface side wall that is arranged to face the pressure surface side wall across the trailing edge passage and has an outer surface that forms a trailing edge side region of the negative pressure surface.
The trailing edge is the thickness of the first wall which is one of the pressure surface side wall or the negative pressure surface side wall, and the thickness of the second wall which is the other of the pressure surface side wall or the negative pressure surface side wall. It has a wall thickness reduction part 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
A connection region that extends into the trailing edge passage and is provided with a plurality of connecting portions that are connected to the pressure surface side wall on one end side and connected to the negative pressure surface side wall on the other end side.
Includes a rear area behind the connection area
The wall thickness reduction portion is at least partially present in the continental zone.
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 .

Claims (14)

A pressure surface and a negative pressure surface extending between the front edge and the trailing edge,
A trailing edge including the trailing edge and a trailing edge passage that opens into the trailing edge, and
A turbine blade with an airfoil that includes
The trailing edge
A pressure surface side wall having an outer surface forming a trailing edge side region of the pressure surface,
Includes a negative pressure surface side wall that is arranged to face the pressure surface side wall across the trailing edge passage and has an outer surface that forms a trailing edge side region of the negative pressure surface.
The trailing edge is the thickness of the first wall which is one of the pressure surface side wall or the negative pressure surface side wall, and the thickness of the second wall which is the other of the pressure surface side wall or the negative pressure surface side wall. It has a wall thickness reduction part that gradually decreases toward
In the wall thickness reducing portion, a turbine blade in which 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 of the airfoil portion. The turbine blade according to claim 1, wherein the first wall is a side wall of a negative pressure surface. Inside the airfoil, a cavity extending along the blade height direction in front of the trailing edge passage is provided.
The turbine blade according to claim 2, wherein the airfoil portion is not provided with a film hole connected to the cavity and opened in the negative pressure surface. Inside the airfoil, a cavity extending along the blade height direction in front of the trailing edge passage is provided.
The turbine blade according to claim 2 or 3, wherein the airfoil portion is provided with a film hole connected to the cavity and opened in the pressure surface. The first wall is the side wall of the pressure surface and
Inside the airfoil, a cavity extending along the blade height direction in front of the trailing edge passage is provided.
The turbine blade according to claim 1, wherein the airfoil portion is provided with a film hole connected to the cavity and opened in the negative pressure surface. The first wall is the side wall of the pressure surface and
Inside the airfoil, a cavity extending along the blade height direction in front of the trailing edge passage is provided.
The turbine blade according to claim 1 or 5, wherein the airfoil portion is not provided with a film hole connected to the cavity and opened in the pressure surface. The trailing edge portion extends into the trailing edge passage, and is provided with a plurality of connecting portions connected to the pressure surface side wall on one end side and connected to the negative pressure surface side wall on the other end side. Including
The turbine blade according to any one of claims 1 to 6, wherein the wall thickness reducing portion is present at least partially in the connection region. The trailing edge includes a posterior region posterior to the connection region.
The turbine blade according to claim 7, wherein 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. In the wall thickness reducing portion, the trailing edge passage has a shape that is curved in a cross section orthogonal to the blade height direction while the width in the direction orthogonal to the camber line gradually decreases toward the trailing edge. 8. The turbine blade according to any one of 8. Any one of claims 1 to 9 in which the ratio t1 / t2 of the thickness t1 of the first wall to the thickness t2 of the second wall is 0.5 or more and less than 1 in the wall thickness reducing portion. Turbine blades described in. In any one of claims 1 to 10, the wall thickness reduction rate with respect to the position change along the camber line of the second wall in the wall thickness reduction portion is larger than the wall thickness reduction rate of the first wall. Described turbine blades. Inside the airfoil portion, a cavity extending along the blade height direction on the front edge side of the trailing edge passage in the cord direction of the airfoil portion and 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 negative pressure surface side cavity wall connected to the negative pressure surface side wall and having an outer surface forming the negative pressure surface and an inner surface forming the cavity is provided.
The thickness of one of the pressure surface side cavity wall and the negative pressure surface side cavity wall connected to the first wall is the thickness of 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 11, which is smaller than the thickness of one of the connected blades. Inside the airfoil portion, a cavity extending along the blade height direction on the front edge side of the trailing edge passage in the cord direction of the airfoil portion and 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 negative pressure surface side cavity wall connected to the negative pressure surface side wall and having an outer surface forming the negative pressure surface and an inner surface forming the cavity is provided.
The thickness of one of the pressure surface side cavity wall and the negative pressure surface side cavity wall connected to the first wall is the thickness of 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 11, which is larger than the thickness of one of the connected blades. The turbine blade according to any one of claims 1 to 13.
A combustor for generating combustion gas flowing through a combustion gas flow path provided with the turbine blades, and a combustor.
A gas turbine equipped with.

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