JP2002061518A - gas turbine - Google Patents

Abstract

(57) [Problem] To provide a gas turbine that prevents leakage of a cooling medium from a gap and does not cause a decrease in plant efficiency or a reduction in reliability of the gas turbine itself due to the leakage of the cooling medium. An annular seal groove (33) is formed on an outer peripheral contact surface between a rotor disk (2) and disks (3, 4). An annular metal wire 40 having a circular cross section is inserted into the annular seal groove 33. The annular wire 40 has an engaging portion in the circumferential direction, one end of the engaging portion has a half-moon cross section, and the other end of the engaging portion also has a half-moon cross section. The shape forming portion and the other half-moon-shaped forming portion overlap each other to form an annular shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine, and more particularly to a gas turbine suitable for application to a structure in which a cooling medium is supplied to and recovered from turbine blades through a flow passage in a rotor disk. .

[0002]

2. Description of the Related Art A gas turbine is configured so that fuel is added to a working fluid compressed by a compressor and burned to obtain a high-temperature and high-pressure working fluid to drive the turbine. The rotational energy of the turbine is converted to electrical energy by, for example, a generator coupled to the turbine.

In recent years, great expectations have been placed on improving the efficiency of a combined cycle in which a gas turbine and a steam turbine are combined. As one means for achieving this, a higher working fluid temperature and a higher pressure ratio have been achieved. Furthermore, in conjunction with the increase in temperature, the cooling medium in the gas turbine high-temperature section, which has been released into the mainstream gas, is recovered at the inlet of the combustor, for example, so that thermal energy is effectively used to further improve efficiency. The development of gas turbines that employ a closed cooling system is also underway.

In general, a cooling medium for the moving blade is supplied to the moving blade through a flow passage formed inside a rotor disk or a downstream disk integrally assembled by stacking bolts. In a gas turbine employing a closed cooling system, the cooling medium after blade cooling is supplied to the flow path inside the rotor disk at a higher pressure than a conventional open cooling system in which all the cooling medium is discharged into a mainstream gas. For this reason, a large pressure difference between the inside and the outside of the rotor disk causes a large amount of cooling medium to leak from a small gap such as a contact portion. Then, for example, Japanese Patent Application Laid-Open No. 10-3
As described in Japanese Patent Application Laid-Open No. 0405, there is known a structure in which a seal groove is provided at a contact portion between rotor disks that are in contact with each other, and a seal spring is inserted into the seal groove to prevent leakage of a cooling medium.

[0005]

However, in the operating state from the start of the gas turbine, the circumferential length of the seal groove greatly changes due to thermal expansion and centrifugal force, and the circumferential extension of the seal spring changes in the seal groove. Unless it follows the elongation in the circumferential direction, a bias occurs, and the seal spring is deformed or damaged, and there is a problem that a sufficient sealing effect cannot be obtained. In addition, in the operating state from the start of the gas turbine,
The gap between the contact portion of the rotor disk and the downstream disk changes greatly due to various effects such as thrust, thermal expansion, and centrifugal force. The variation of the gap reaches about +0.5 mm depending on the design conditions. In such a case, the diameter 6.
Even if these variations are absorbed by the elastic deformation of the 4-mm metal C seal, the range of the elastic deformation is 0.4 mm, and there is a problem that the variations cannot be sufficiently absorbed.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the leakage of the cooling medium from the gap even if the circumferential length of the seal groove and the gap between the rotor disk and the downstream disk contact portion facing each other greatly change during the operation from the start of the gas turbine. It is another object of the present invention to provide a gas turbine that does not cause a decrease in plant efficiency or a decrease in reliability of the gas turbine itself due to leakage of a cooling medium.

[0007]

(1) In order to achieve the above object, the present invention provides a rotor disk holding a moving blade having a cooling medium flow passage therein, and a rotor disk which contacts the rotor disk and which A disk having a flow passage communicating with the cooling medium flow passage.
An annular seal groove formed in at least one of the outer peripheral contact surface of the rotor disk and the disk, and an annular metal wire having a circular cross section inserted into the annular seal groove; The wire has an engaging portion in the circumferential direction, one end of the engaging portion has a half-moon shape in cross section, and the other end of the engaging portion has a half-moon shape in cross section. The shape forming part and the other half-moon-shaped forming part overlap each other to form an annular shape. With this configuration, during operation of the gas turbine, the annular wire receives a force in a radially outward direction due to the centrifugal force due to rotation and the pressure of the cooling medium inside the rotor disk being larger than the pressure of the external atmosphere, and furthermore, the engaging portion is Is not constrained in the circumferential direction, so that it closely adheres to the seal groove wall, closes the gap between the rotor disks, and prevents leakage of the cooling medium.

(2) In the above (1), preferably,
The annular wire is installed such that a surface that overlaps the half-moon forming portion at one end of the engaging portion and the half-moon forming portion at the other end is perpendicular to the rotor disk contact surface. . With this configuration, the leakage area in the engagement portion can be minimized, and the amount of leakage from this region can be reduced.

(3) In the above (1), preferably,
The seal groove is formed so as to have a constant depth portion and become shallower as the groove depth goes from the inner periphery to the outer periphery. With this configuration, when the annular wire moves to the outer peripheral side during operation, the seal groove wall serves as a guide,
A structure that can more easily close the gap between the rotor disks can be obtained.

(4) In the above (1), preferably,
The seal groove is formed so that the groove depth becomes gradually shallower from the inner circumference to the outer circumference. With this configuration, when the annular wire moves to the outer peripheral side during operation, the seal groove wall serves as a guide, and a structure that can more easily close the gap between the rotor disks can be obtained.

(5) In the above (1), preferably,
The annular wire includes a concave rail groove provided in a half-moon forming portion at one end of the engagement portion, and a convex rail provided in a half-moon forming portion at the other end, and the rail groove has the rail. Are formed so as to be inserted. With such a configuration, it is possible to prevent the center axes of the wires from being shifted from each other in the engagement portion, and it is possible to more reliably prevent leakage.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a gas turbine according to a first embodiment of the present invention will be described below with reference to FIGS. First, the structure around the rotor blades and the rotor disk of the gas turbine according to the present embodiment will be described with reference to FIG. FIG. 1 is a sectional view showing a structure around a rotor blade and a rotor disk of a gas turbine according to a first embodiment of the present invention.

The moving blade 1 is held on a rotor disk 2. The upstream disk 3, the rotor disk 2 and the downstream disk 4 are integrated by a stacking bolt 5 to form a rotating body. A cavity 10 for supplying a cooling medium to the moving blade 1 is formed between the upstream disk 3 and the rotor disk 2. On the other hand, a cavity 11 is formed between the rotor disk 2 and the downstream disk 4 for collecting a cooling medium that has cooled the rotor blades 1.

In the structure thus formed, the cooling medium 12 is supplied to the cavity 10 through the flow path 6 provided in the rotor disk. Further, the cooling medium 12
The cooling medium supply passage 2 provided in the rotor disk 2
0, the cooling medium is supplied to the cooling medium supply port 22 provided in the dovetail 8 of the bucket 1. On the other hand, the cooling medium 12 which has finished cooling the moving blade 1 is collected in the cavity 11 through a cooling medium collecting passage 23 of the rotor disk 2 from a cooling medium collecting port 23 provided in the dovetail 8 of the moving blade 1. further,
It is collected by the flow path 7 and finally collected at the upstream combustor inlet.

In a system employing the closed cooling system for recovering the cooling medium as described above, an external boost compressor or the like is provided so that the blade cooling medium can be finally recovered to the combustor inlet having the highest pressure. Since the pressure is increased and supplied, there is a large pressure difference between the cooling medium pressure inside the rotor disk and the atmospheric pressure outside the rotor disk. Due to this pressure difference, the cooling medium leaks from the gap, and the leakage of the cooling medium causes a reduction in plant efficiency and a reduction in the reliability of the gas turbine itself.

Therefore, in the present embodiment, a solid metal annular wire 40 having a circular cross section is inserted into the gap between the contact surfaces of the rotor disk 2 and the upstream disk 3.
Similarly, a solid metal annular wire 40 having a circular cross section is inserted in the contact surface gap between the rotor disk 2 and the downstream disk 4. Details of the insertion structure of the annular wire 40 will be described later with reference to FIGS.

Next, a detailed structure around the rotor blades and the rotor disk of the gas turbine according to the present embodiment will be described with reference to FIG. FIG. 2 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of the gas turbine according to the first embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

In the gap 30 between the contact surface between the rotor disk 2 and the upstream disk 3, a seal groove 33 is provided on the upstream disk 3 side.
Is provided. A wall 36 is formed in the seal groove 33 so as to be tapered in a radially outward direction. A solid metal annular wire 40 having a circular cross section is inserted into the seal groove 33.

Here, the configuration of the metal annular wire 40 used in the gas turbine according to the present embodiment will be described with reference to FIGS. FIG. 3 is a perspective view showing the configuration of the metal annular wire 40 used for the gas turbine according to the first embodiment of the present invention, and FIG.
FIG. 5 is a sectional view taken along line A of FIG. 3, and FIG. 5 is a sectional view taken along line BB of FIG.
Note that the same reference numerals as those in FIG. 2 indicate the same parts.

As shown in FIG. 3, the annular wire 40 is provided with a dividing portion 70. One end 71 of the divided portion 70 has a half-moon cross section in the drawing,
The upper half is cut into a shape. The other end 72 of the divided portion 70 is formed in a shape in which a lower half is cut so that a cross section becomes a half-moon shape. The annular wire 40 is configured such that the flat portion 73 of the wire end 71 and the flat portion 74 of the wire end 72 overlap in the split portion 70. That is, the wire end 71 and the wire end 72 are formed so that the overlapping surface 75 can move freely in the circumferential direction 93 and the wire circumference can be changed within a design range. The overlapping surface 75 is formed so as to be perpendicular to the rotor disk end surface 32.

As shown in FIG. 2, during operation of the gas turbine, centrifugal forces 60 and 61 due to rotation act on both the rotor disk 2 and the upstream disk 3 and simultaneously thermal expansion occurs. The contact surface 30 with the upstream disk 3 moves radially outward. Also, at this time, the centrifugal force 60 acting on the rotor disk 2 holding the rotor blade 1 and the centrifugal force 61 acting on the upstream disk 3 have different magnitudes. Slide radially. At this time, the seal groove 33 moves outward in the radial direction due to the thermal expansion of the upstream disk 3, and its division length becomes longer. Also,
Since the contact surface gap 31 is set in consideration of the amount of thermal elongation in a high temperature state during operation, the clearance is designed to be large to some extent at the time of startup in order to release the thermal elongation in the rotation axis direction.

In such a case, in the gas turbine adopting the closed cooling system, the pressure of the cooling medium 12 is much higher than the atmospheric pressure outside the rotor disk.
It is necessary to prevent a large amount of the cooling medium 12 from leaking from the gap 31. Because the cooling medium 12 is a medium whose pressure has been increased by the boost compressor, if a leak occurs, the power of the boost compressor is lost, resulting in a significant reduction in the efficiency of the entire plant. If sufficient cooling medium 12 cannot be supplied to bucket 1 due to leakage,
The rotor blade 1 may be damaged due to insufficient cooling.

Therefore, in the present embodiment, the leakage of the cooling medium is prevented by using the annular wire 40 as shown in FIGS. That is, in the present embodiment, even if the circumferential length of the seal groove changes due to the centrifugal force acting on the upstream-side disk 3 and thermal deformation, the annular wire 40 in the seal groove 33 causes the centrifugal force and the pressure difference to move outward in the radius of rotation. , And can be freely extended in the circumferential direction within the design range due to the presence of the divided portion 70. Further, within the fluctuation of the contact surface gap 31 during operation, the annular wire 40 is connected to the gradient wall 36 of the seal groove 33 and the rotor disk 2.
And has an action of closing the gap 31.

Also, as shown in FIG. 3, since the overlapping surface 75 of the dividing portion 70 is perpendicular to the rotor disk end surface, the leakage from the regions 76 and 77 where the wire ends 71 and 72 do not overlap is considered. In the region 76, as shown in FIG. 4, since the edge 78 of the semicircular wire contacts the rotor disk end surface 32, the leakage area is only the region 90 between the seal groove 33 and the wire end 71,
Leakage 91 can be suppressed to a very small amount. Further, area 7
In FIG. 7, as shown in FIG. 5, the edge 79 of the semicircular wire comes into contact with the rotor disk end face 32, and the arc portion 80 comes into contact with the sloped wall 36, so that leakage can be prevented. Can be minimized.

In the above description, the rotor disk 2
The method for preventing leakage of the cooling medium 12 from the cooling medium supply cavity 10 formed by the upstream disk 3 and the cooling medium recovery cavity 11 formed by the rotor disk 2 and the downstream disk 4 has been described. It is possible to prevent leakage of the medium in the same manner.

As described above, according to the present embodiment, the cooling medium in the rotor disk flows to the mainstream gas side in all operating states from the start of the gas turbine to the load operation state and further to the stop. Leakage can be prevented, and the reliability of the gas turbine can be prevented and the reliability can be improved.

Next, the structure of a gas turbine according to a second embodiment of the present invention will be described with reference to FIG. The structure around the rotor blades and the rotor disk of the gas turbine according to the present embodiment is the same as that shown in FIGS. The present embodiment is particularly characterized by the configuration of the annular wire. Hereinafter, the configuration of the annular wire according to the present embodiment will be described with reference to FIG. FIG.
FIG. 6 is a perspective view showing a configuration of a metal annular wire 40b used in a gas turbine according to a second embodiment of the present invention. The same reference numerals as those in FIGS. 1 to 5 indicate the same parts.

Wire end 71b of annular wire 40b
A rail groove 81 is provided in the flat portion 73b. Further, a rail 82 is provided on the plane portion 74b of the other wire end 72b. And the annular wire 40b
Is formed so that the rail 82 slides in the rail groove 81.

By providing the structure according to the present embodiment, it is possible to prevent the respective central axes of the wire end 71b and the wire end 72b from shifting. Therefore, it is possible to prevent the wire end 71b from fluctuating and the edge 78b from separating from the rotor disk end face 32, and it is possible to more reliably prevent leakage.

As described above, according to this embodiment, it is possible to more reliably prevent the cooling medium in the rotor disk from leaking to the mainstream gas side, thereby preventing the performance of the gas turbine from deteriorating and improving the reliability. Can be achieved.

Next, the structure of a gas turbine according to a third embodiment of the present invention will be described with reference to FIG. The structure around the rotor blades and the rotor disk of the gas turbine according to the present embodiment is the same as that shown in FIG.
The present embodiment is particularly characterized by the seal portion structure. Hereinafter, the seal portion structure according to the present embodiment will be described with reference to FIG. FIG. 7 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of a gas turbine according to a third embodiment of the present invention. In addition,
1 to 5 indicate the same parts.

In the contact gap 31 between the rotor disk 2 and the upstream disk 3, seal grooves 33b and 32 are provided on both sides.
b is provided. The seal groove walls 36b and 35b on the outer peripheral side of the seal grooves 33b and 32b are provided with a gradient to form a C-shape.

Even in such a structure, the annular wires 40, 4 having the structure shown in FIGS.
By using Ob, even if the seal grooves 33b and 32b have a step in the radial direction during operation of the gas turbine, the annular wires 40 and 40b are lifted to the outer peripheral side by the force 62 due to the centrifugal force and the pressure difference, and the seal groove wall 36b And 35b
To close the gap 31 at the contact portion, thereby preventing the cooling medium from leaking to the outside.

As described above, according to the present embodiment, it is possible to prevent the cooling medium in the rotor disk from leaking to the mainstream gas side, thereby preventing the performance of the gas turbine from deteriorating and improving the reliability. Can be.

Next, the structure of a gas turbine according to a fourth embodiment of the present invention will be described with reference to FIG. The structure around the rotor blades and the rotor disk of the gas turbine according to the present embodiment is the same as that shown in FIG.
In the present embodiment, the seal structure is particularly characterized. The seal structure according to the present embodiment will be described below with reference to FIG. FIG. 8 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of a gas turbine according to a fourth embodiment of the present invention. In addition,
1 to 5 indicate the same parts.

In the contact gap 31 between the rotor disk 2 and the upstream disk 3, seal grooves 33c and 32 are provided on both sides.
c is provided. The seal groove walls 36c and 35c on the outer peripheral side of the seal grooves 33c and 32c are provided with a gradient to form a smooth C-shape.

In such a structure, the annular wires 40, 4 having the structure shown in FIG. 3 to FIG. 5 or FIG.
By using Ob, even if radial gaps occur in the seal grooves 33c and 32c during operation of the gas turbine, the annular wires 40 and 40b are lifted to the outer peripheral side by the force 62 due to the centrifugal force and the pressure difference, and the outer peripheral side seal is sealed. Since the gaps 31 at the contact portions are closed and stably adhered to the groove walls 35b and 36b, the reliability of the sealing effect is improved.

As described above, according to the present embodiment, it is possible to prevent the cooling medium in the rotor disk from leaking to the mainstream gas side, thereby preventing the performance of the gas turbine from deteriorating and improving the reliability. Can be.

In the above embodiments, the case where steam is used as the cooling medium has been described.
It can be applied to various cooling media such as air, water, nitrogen, and helium. In any case, a highly reliable cooling medium recovery type gas turbine can be obtained.

[0040]

According to the present invention, even if the circumferential length of the seal groove and the gap between the rotor disk and the downstream disk contact portion facing each other greatly change during the operation from the start of the gas turbine, the leakage of the cooling medium from the gap. Can be prevented, the plant efficiency can be improved, and the reliability of the gas turbine can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure around a rotor blade and a rotor disk of a gas turbine according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of the gas turbine according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration of a metal annular wire 40 used for the gas turbine according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a perspective view showing a configuration of a metal annular wire 40b used in a gas turbine according to a second embodiment of the present invention.

FIG. 7 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of a gas turbine according to a third embodiment of the present invention.

FIG. 8 is an enlarged sectional view of a main part showing a detailed structure around a rotor blade and a rotor disk of a gas turbine according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Moving blade 2 ... Rotor disk 3 ... Upstream disk 4 ... Downstream disk 5 ... Stacking bolt 6 ... Cooling medium flow path 7 ... Cooling medium flow path 8 ... Moving blade dovetail 10 ... Cooling medium supply cavity 11 ... Cooling medium recovery Cavity 12 ... Cooling medium 20 ... Cooling medium supply flow path 21 ... Cooling medium recovery flow path 22 ... Cooling medium supply port 23 ... Cooling medium recovery port 30 ... Rotator disk contact surface 31 ... Rotator disk contact surface gap 32,32b, 33b, 33c: seal groove 35, 35b, 36b: outer peripheral side seal groove wall 36: seal groove gradient wall 40, 40b: wire 70: wire division 71, 71b, 72, 72b: wire end 73, 73b, 74, 74b Wire end flat portion 75: Wire end overlapping surface 76, 77 ... Wire end non-overlapping surface 78, 78b, 79 ... Ear end edge 80 ... wire arc portion 81 ... rail groove 82 ... rail

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor: Manabu Matsumoto 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in the Electric Power and Electric Development Laboratory, Hitachi, Ltd. 3G002 AA02 AA06 BA02 FA00 HA01

Claims (5)

[Claims] 1. A gas turbine comprising: a rotor disk holding a rotor blade having a cooling medium flow passage therein; and a disk contacting the rotor disk and having a flow passage communicating with the cooling medium flow passage. An annular seal groove formed on at least one of the rotor disk and the outer peripheral contact surface of the disk; and an annular metal wire inserted into the annular seal groove and having a circular cross section. The wire has an engaging portion in the circumferential direction, one end of the engaging portion has a half-moon shape in cross section, and the other end of the engaging portion has a half-moon shape in cross section. A gas turbine characterized in that an annular shape is formed by overlapping a shape forming portion and a half-moon shape forming portion at the other end with each other. 2. The gas turbine according to claim 1, wherein the annular wire has a surface that overlaps a half-moon forming portion at one end of the engaging portion and a half-moon forming portion at the other end of the engaging portion. A gas turbine characterized by being installed perpendicular to a plane. 3. The gas turbine according to claim 1, wherein the seal groove is formed so as to have a constant depth portion and then become shallower as the groove depth goes from the inner circumference to the outer circumference. Characterized gas turbine. 4. The gas turbine according to claim 1, wherein the seal groove is formed so that the groove depth becomes gradually shallower from the inner periphery toward the outer periphery. 5. The gas turbine according to claim 1, wherein the annular wire is provided in a concave rail groove provided in a semilunar forming portion at one end of the engaging portion and in a semilunar forming portion at the other end. A gas turbine, comprising: a convex rail; and a rail inserted into the rail groove.