JPH03182601A - Turbine rotor blade - Google Patents

Abstract

PURPOSE:To prevent a blade shaft from damage even under the environment of high temperature operating gas by forming a tip end flange for supporting jackets and a blade shaft core part integrally. CONSTITUTION:A turbine rotor blade 20 is provided with an embedded part 21a to be embedded in a turbine shaft 1 and a core part 21b to be protruded from the turbine shaft 1. The core part 21b is provided with a blade shaft 21 at which a bottom flange 22 and a tip end flange 23, respectively provided with jacket insertion grooves 24a, 24b on mutually opposed faces, are integrally formed at the bottom and tip end. The core part 21b is further provided with jackets 26a, 26b with both end faces thereof fitted into the jacket insertion grooves 24a, 24b of both flanges 22, 23 as well as jointed mutually in the airtight state. As the tip end flange 23 for supporting the jackets 26a, 26b and the core part 21b are thus formed integrally, both are prevented from being separated- damaged even if centrifugal force works at the time of operating a gas turbine.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a turbine rotor blade used in a gas turbine or the like, and in particular, the blade shaft that rotates at high speed can be used even in a high-temperature working gas environment. This invention relates to a turbine rotor blade that is not likely to be damaged.

(Prior Art) FIG. 6 is a cutaway sectional view of a gas turbine 1 used in a gas turbine power generation plant or the like.

A compressor 3 provided coaxially with the turbine shaft 2 takes in air, compresses it, and sends it to a fuel device 4 as compressed air. In the combustor 4, this compressed air and the fuel introduced into the combustor 4 are mixed to form an air-fuel mixture, and this air-fuel mixture is further ignited and combusted. The high-temperature, high-pressure combustion gas (indicated by the dashed arrow) generated by combustion is transferred to the transition piece 5.
, and is introduced into the turbine stator blades 6 and then the turbine rotor blades 7, and is then guided alternately to the turbine stator blades 6 and the turbine rotor blades 7. By rotating the turbine rotor blades 7, the turbine shaft 2 is rotationally driven.

Note that, in the turbine rotor blade 7, the side with which the combustion gas collides is the high-pressure side, and the opposite side is the low-pressure side. Furthermore, a vent pipe (not shown) is embedded within the turbine shaft 1 to allow compressed air obtained by the compressor 3 to pass therethrough as cooling air. Furthermore, in this type of gas turbine 1, it is known that increasing the turbine inlet temperature improves the thermal efficiency of the gas turbine 1.

FIG. 7 is a sectional view of the turbine rotor blade 7 shown in FIG.
The figure is a sectional view taken along the line ■--■ in FIG.

The blade shaft 8 has a plurality of cooling air passages 9 passing through it in the axial direction and communicating with the above-mentioned turbine shaft ventilation pipe, and has an implant part 8a implanted in the turbine shaft 1 and a core part 8b protruding from the turbine shaft. have A flange 10 is provided at the root of the wing shaft core portion 8b.
is formed. This flange 10 prevents high-temperature working gas from penetrating into the installation location of the blade shaft installation portion 8a on the turbine shaft 1 and causing thermal damage thereto. Note that the wing axis 8 is
It is manufactured from a heat-resistant superalloy such as a Ni-based alloy so that it can withstand high-temperature combustion gases.

The wing shaft 8 is inserted into the cylindrical outer sheath 11 with its end surface in contact with the flange 10, and the wing shaft core portion 8b
The top cover ↓2 is joined to the tip of the blade while being in contact with the outer cover 11 (the joint surface between the wing shaft core portion 8b and the top cover 12 is indicated by the symbol A).

A gap] 3 is maintained between the blade shaft core portion 8b and the outer cover 11. Note that the top cover 12 also has a cooling air flow path 14,
This cooling air passage 14 communicates with the cooling air passage 9 of the blade shaft 8 . Further, the top cover 12 is also made of a heat-resistant superalloy such as a Ni-based alloy, and is joined to the wing shaft core portion 8b by diffusion bonding or the like.

The outer sheath 11 is usually made of ceramic such as Si3N4 or SiC, which lacks toughness but has higher heat resistance than the heat-resistant superalloy that makes up the blade shaft 8, and the blade shaft core 8b, which has a large surface area, absorbs hot combustion gas. Prevent direct exposure to (working gas). The blade shaft 8 must be made of metal (heat-resistant superalloy) so that it can withstand tensile stress caused by centrifugal force during rotation. However, even heat-resistant superalloys have a
If it rotates at high speed while being directly blown by high-temperature combustion gas (working gas) that reaches temperatures as high as 0C, there is a risk of damage. Therefore, by surrounding it with the outer cover 11, the wing shaft core portion 8b is protected from damage caused by heat. Furthermore, the void ↑
3 prevents heat conduction between the outer sheath 11 and the wing shaft core portion 8b.

Further, the cooling air passes through the cooling air flow path 9 from the implanted portion 8a toward the core portion 8b, and passes through the cooling air flow path 1 of the top cover 12.
4 to the outside of the turbine rotor blade 7, but during this time the blade shaft 8
This cooling air also serves to protect the wing shaft core portion 8b and the top cover 12 from thermal damage.

(Problem to be solved by the invention) By the way, when the turbine rotor blade 7 is rotated, centrifugal force acts on the blade shaft 8, outer sheath 11, and top cover 12, and high tensile stress acts on the joint surface A. As a result, there is a possibility that insufficient bonding or defects may occur on the bonding surface, but since the bonding surface A is covered with the outer cover 11, these defects cannot be discovered from the outside. Therefore, the turbine rotor blade 7 may be damaged from this joint surface A.

In addition, the outer cover 11 presses the top cover 12 by centrifugal force, while creating a clearance δ in the axial direction between the outer cover 11 and the flange 10. Then, the high-temperature combustion gas surrounding the jacket 11 enters the gap 13 from this clearance δ,
The cooling effect of the cooling air on the blade shaft 8 and the top cover 12 is inhibited, and thermal stress is generated therein. Therefore, if insufficient bonding or defects occur on the bonding surface A, there is a risk that these defects will be further enlarged.

Furthermore, if the cooling effect of the cooling air is inhibited by the working gas that has entered the air gap 13, the blade shaft 8 and the top cover 12
expands thermally. Then, since the thermal expansion coefficient of the heat-resistant superalloy that is the material of the wing shaft 8 and the top cover 12 is about three times that of the ceramic that is the material of the outer cover, the contact between the outer cover 11 and the top cover 12 is A large frictional force is generated in the area. As a result, strong tensile stress or shear stress is generated at the contact portion of the outer sheath with the top cover 12, and the outer sheath 11 made of ceramic may be damaged.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a turbine rotor blade whose blade shaft, which rotates at high speed during operation of a gas turbine, is not likely to be damaged even in a high-temperature working gas environment.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention includes an implanted part implanted in the turbine shaft and a core part protruding from the turbine shaft, and this core part is provided at the root and tip. The wing shaft includes a wing shaft in which a root flange and a tip flange are integrally formed, each having a recessed portion on a surface facing each other, and a plurality of outer sheaths whose end surfaces are fitted into the recessed portions of the flanges and are airtightly joined to each other. Provides turbine rotor blades that

(Function) The turbine rotor blade of the present invention includes an implanted part implanted in the turbine shaft and a core part protruding from the turbine shaft, and this core part has a recessed part at the root and the tip, respectively, on opposing surfaces. The blade shaft has a root flange and a tip flange that are integrally formed, and a plurality of outer sheaths whose end surfaces are fitted into the recessed portions of the flanges and are hermetically joined to each other.

That is, in the turbine rotor blade of the present invention, since the tip flange supporting the outer sheath and the blade shaft core are integrally formed,
Even if centrifugal force is applied during operation of the gas turbine, the two will not separate or be damaged.

Furthermore, in the turbine rotor blade of the present invention, since the outer sheath is composed of a combination of a plurality of pieces, the individual outer sheaths can be attached from the outside of the blade shaft by fitting them into the recessed portions of the root flange and the tip flange. . As a result, the outer sheath is not simply abutted against the wing axis, so even when centrifugal action occurs, the outer sheath lifts off the root flange.
Working gas does not enter the inside of the jacket through the gap.

Therefore, excessive thermal stress or thermal expansion does not occur on the blade shaft, and the integrity of the turbine rotor blades is maintained.

(Example) The present invention will be described in detail below with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view of a turbine rotor blade 20 according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line nn in FIG. 1.

The blade shaft 21 consists of an implanted part 21a implanted in the turbine shaft 1 and a core part 21b protruding from the turbine shaft 1, a root flange 22 at the root of the core part 21b, and a tip flange 23 at the tip of the core part 21b. are integrally formed. The material of the wing shaft 21 and both flanges 22, 23 is a heat-resistant superalloy. Covering insertion grooves 24a and 24b are provided as recessed portions on the mutually opposing surfaces of the root flange 22 and the tip flange 23, that is, on the upper surface of the root flange 22 and the lower surface of the tip flange 23, respectively. In addition, a plurality of cooling air flow paths 25 pass through the blade shaft 21 from the implanted portion 21a, pass through the core portion 21b, and branch at the tip flange. Further, in this embodiment, a cooling air branch passage 26 is passed through from the cooling air flow passage 25 of the wing shaft implantation portion 21a toward the jacket insertion grooves 24a and 24b. The jacket insertion groove 24b is tapered so as to increase in depth from the outer circumferential side of the tip flange 23 toward the inner circumferential side.

In this embodiment, the leading edge outer sheath 26a and the trailing edge outer sheath 26a
b while maintaining the air gap 27 between them and the wing shaft 21,
The blade shaft 21 is airtightly joined along the axial direction of the wing shaft 21 to form a cylindrical outer sheath 26. The cylinder diameter of the outer sheath 26 is the same as that of the root flange 22.
is smaller than the width diameter of the tip flange 23, but in this embodiment, the front side outer cover 26a and the rear edge side outer cover 26a are attached at the front.
Since it is divided into two parts 6b, it is possible to mount it inside the width diameter of the root flange 22 and the tip flange 23.

The material of both the outer sheaths 26a and 26b is ceramic, which is more resistant to heat than the heat-resistant superalloy that is the material of the wing shaft 2. The high-pressure side and low-pressure side joint surfaces of the leading edge side outer cover 26a and the trailing edge side outer cover 26b are respectively denoted by reference numeral 28a.

28b. The two outer sheaths 26a and 26b are fitted into the outer sheath insertion grooves 25a and 25b through friction reducing pads 29a and 29b made of boron nitride or the like on the base flange 22 and tip flange 23 sides, respectively. The outer coverings 26a, 26b and the friction reducing pads 29a, 29b are joined. Note that the contact portions of the outer coverings 26 a, 26 b with the friction reducing pads 29 a, 29 b are tapered so that the wing shaft core portion 21 b side extends.
The contact surface on the side 9b is machined to match the inclination angle of the bottom of the jacket insertion groove 24b. Due to such taper processing, the outer sheaths 26a and 26b are inserted into the outer sheath m25a.

It becomes easier to fit into 25b.

In this embodiment, a through hole 30 is provided in the jacket insertion groove 22a in the axial direction of the blade shaft 21. A bushing pin 31 is inserted into the through hole 30, and pushes up the jacket pressing block 33, which is housed in the jacket insertion groove 25a while maintaining a gap 32 between it and the side wall. the result,
The outer cover pressing block 33 comes into contact with the friction reducing pad 29a, but if it is pushed up further, the friction reducing pad 29a will come into contact with it.
b comes into close contact with the bottom of the jacket insertion groove 25b. The bushing pin 31 is fixed to the through hole 30 at the time of this close contact.

Now, when the turbine rotor blade 20 of this embodiment is rotated by applying high-pressure combustion gas, centrifugal force acts on the blade shaft 21, the tip flange 23, and the outer cover 26. However, since the wing shaft core section 21 and the tip flange 23 are integrally formed, even if the outer jackets 26 a and 26 b press the tip flange 23 , the tip flange 23 will not be torn off from the wing shaft core section 21 . There's nothing to do.

On the other hand, even if the outer sheaths 26a and 26b are pressed in the direction of the tip flange 23 due to centrifugal action, the outer sheath holding block 33 fitted in the outer sheath insertion groove 24a will be lifted from the outer sheath insertion groove 24a. It never comes off. Also,
A joint surface 28a between the leading edge outer covering 26a and the trailing edge outer covering 26b,
28b is also kept airtight. Therefore, the outer coverings 26a, 2
The working gas surrounding 6 does not enter the gap 27. At this time, the cooling air passes through the cooling air flow path 25 to cool the core portion 21b and the tip flange 23, but the cooling air that enters the cooling air branch path 26 cools the root flange 22 and flows into the jacket insertion groove 24a. After exiting, it passes through the gap 32 and is discharged to the outside of the turbine rotor blade 20 . Therefore, the cooling air passing through the gap 32 also serves to prevent the working gas from entering the jacket insertion groove 24a and accidentally entering the gap 27.

Furthermore, since a friction reducing pad 29b is interposed between the tip flange 23 and the outer sheaths 26a and 26b, the tip flange 23
Even if 3 undergoes unavoidable thermal expansion, no large frictional resistance will occur between the outer sheaths 26a and 26b, which have smaller coefficients of thermal expansion. Therefore, no tensile stress or shear stress is generated in the outer sheaths 26a, 26b, and the outer sheaths 26a, 26b
There is no risk of damage.

FIG. 3 shows the pressure distribution from the leading edge to the trailing edge of the outer sheath 26 during operation of the turbine rotor blade 20 according to this embodiment.
It is shown divided into high pressure side and low pressure side. The curve C shows the pressure on the high pressure side, and the curve C shows the pressure on the low pressure side. Further, the distances from the leading edge to the joint surface 28a and the joint surface 28b are indicated by B and C, respectively. As can be seen from the figure, the pressure applied to both joint surfaces 28a and 28b is equal. therefore,
Both joint surfaces 28a and 28b separate from each other due to the pressure difference, and the working gas does not enter the gap 27 from this separated area.

FIG. 4 is a sectional view of a turbine rotor blade 40 according to a second embodiment of the present invention, and FIG. 5 is a sectional view taken along the line V-V in FIG. 4. The basic configuration of the turbine rotor blade 40 according to this embodiment is not substantially different from that shown in FIGS. 1 and 2, so corresponding parts are given the same reference numerals and explanations will be omitted. .

In this embodiment, the jacket presser block 33 fitted into the jacket insertion groove 24a is pressed from below by a spring 34 installed at the bottom of the jacket insertion groove 24a, so that the high-pressure side jacket 35a and the low-pressure The side outer cover 35b is suppressed and supported. Note that the spring 34 presses the outer covers 35a, 35b and the outer cover pressing block 33 from below, and
Any other elastic member may be used as long as it can bring the member 35b into airtight contact with the jacket insertion groove 24b.

In addition, in this embodiment, a plurality of (two) outer sheaths are provided,
That is, the high-pressure side jacket 35a and the low-pressure side jacket 35b are arranged on the high-pressure side and the low-pressure side, respectively, and are hermetically joined at the front edge and the rear edge (the joint surfaces are denoted by 36a and 36, respectively).
b). In this way, there are no particular restrictions on the locations where the plurality of jackets are arranged and where they are joined.

In this embodiment, the air gap 2 is provided in the blade shaft core portion 21b.
A rib 38 is protrudingly provided on the 7 side to abut on the outer sheaths 35a, 35b via a heat insulating pad 37, thereby reinforcing the outer sheaths 35a, 35b from the inside, which are pressed by combustion gas from the outside, to prevent damage.

Further, a sealing material 39 attached to the wing shaft core portion 21b is brought into close contact with the air gap 27 side of the joint surfaces 36a and 36b via a heat insulating pad 40. As a result, the airtightness of the joint surfaces 36a and 36b can be maintained perfectly.

In addition, the above-mentioned heat insulation pads 37 and 40 have an outer cover 35a,
This prevents the heat of the working gas from being transmitted from the blade shaft core portion 21b to the blade shaft core portion 21b.

〔Effect of the invention〕

As described above, the turbine rotor blade of the present invention includes an implanted part implanted in the turbine shaft and a core part protruding from the turbine shaft, and the core part has surfaces facing each other at the root and tip. The blade shaft includes a wing shaft having a root flange and a tip flange integrally formed with a recessed portion, and a plurality of outer sheaths whose end surfaces are fitted into the recessed portions of the flanges and are hermetically joined to each other.

That is, in the turbine rotor blade of the present invention, since the tip flange supporting the outer sheath and the blade shaft core are integrally formed,
Even if centrifugal force is applied during operation of the gas turbine, the two will not separate or be damaged.

Furthermore, in the turbine rotor blade of the present invention, since the outer sheath is composed of a combination of a plurality of pieces, the individual outer sheaths can be attached from the outside of the blade shaft by fitting them into the recessed portions of the root flange and the tip flange. . As a result, the outer sheath is not simply abutted against the wing axis, so even when centrifugal action occurs, the outer sheath lifts off the root flange.
Working gas does not enter the inside of the jacket through the gap.

Therefore, excessive thermal stress or thermal expansion does not occur on the blade shaft, and the integrity of the turbine rotor blades is maintained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a turbine rotor blade according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line nn in FIG. 1, and FIG. A diagram showing the pressure distribution toward the trailing edge, FIG. 4 is a sectional view of a turbine rotor blade according to a second embodiment of the present invention, FIG. 5 is a sectional view taken along the line V-■ in FIG. 4, and FIG. FIG. 7 is a cutaway sectional view of a gas turbine, FIG. 7 is a sectional view of a conventional turbine rotor blade, and FIG. 8 is a sectional view taken along the line ■--■ in FIG. 7. 21a... wing shaft implantation part, 2.1b... wing shaft core part, 2
2... Root flange, 23... Tip flange, 24
a, 24b...Outer cover insertion groove, 26a, 26b outer cover.

Claims (1)

[Claims] It comprises an implanted part implanted in the turbine shaft and a core part protruding from the turbine shaft, and this core part is integrally formed with a root flange and a tip flange, each having a recessed part at the root and the tip, respectively, on opposing surfaces. A turbine rotor blade comprising a blade shaft and a plurality of outer sheaths whose end surfaces are fitted into the recessed portions of the flanges and are hermetically joined to each other.