JP2004156623A - Elastic body sealing device, gas turbine using this, and operation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic body sealing device arranged at a passage in the horizontal direction within a cooling path to a moving blade of a turbine which is a high-temperature non-cooldown part with increased reliability, simplification of production control and increased work efficiency of assembly work, a gas turbine using the elastic body sealing device and an operation method of the gas turbine. <P>SOLUTION: An elastic body seal 31 is arranged at a position where a flow of cooling medium within the cooling path 18 for cooling the moving blade 21 of the gas turbine 1 is made in the horizontal direction. The elastic body seal 31 consists of a hollow supporting body 34 and a spherical shape elastic body 35. A circular projection 36 with a shorter diameter than a maximum diameter of the spherical shape elastic body 35 is arranged at the outer end of the hollow supporting body 34. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an elastic seal device used for a gas turbine that cools turbine cooling blades or the like using air, steam, or the like as a cooling medium, a gas turbine using the same, and an operation method of the gas turbine. TECHNICAL FIELD The present invention relates to an elastic seal device suitable for preventing performance degradation of a gas turbine intended to improve thermal efficiency, a gas turbine using the same, and an operation method of the gas turbine.

  In a gas turbine, the temperature of a working gas is increased in order to improve thermal efficiency, and a cooling medium is provided inside the blade so that turbine blades arranged in the working gas can withstand this high temperature. And cooling.

  2. Description of the Related Art Conventionally, this type of gas turbine generally used uses air extracted from a compressor as a cooling medium, and cools the cooling air by flowing through the inside of a turbine blade. And it is an open cooling system in which the cooling air after cooling the inside of the blade is discharged into the working gas for film cooling on the outer surface of the blade, from the trailing edge of the blade, etc., and as seal air for the wheel space. .

  In this open cooling method, since the cooling air is discharged into the working gas, the temperature of the working gas decreases due to dilution of the cooling air, which is relatively low, and the working gas when the cooling air is mixed into the working gas. Since the output of the turbine is reduced due to mixing loss or the like occurring between the temperatures, there is a tendency that the effect of increasing the temperature cannot be sufficiently exhibited.

  As a remedy, a cooling air recovery type gas turbine that recovers the cooling air after cooling the part to be cooled into the combustor without discharging it into the working gas, or a heat transfer coefficient to the cooling medium even with the same recovery type A gas turbine using steam having a large volume (contribution of work by reducing the amount of refrigerant consumed and collecting the steam into a steam system) has been proposed.

  In these refrigerant recovery type gas turbines, it is particularly important for the purpose of their development to prevent the occurrence of refrigerant leakage in the cooling path from the supply section of the refrigerant to the recovery section. Closing the system with a pipe is the most effective and simple method as this means. However, in the stationary system path, if piping is provided between the two, such as between the turbine vane and the casing, thermal stress is generated due to a difference in elongation between the two, causing damage to the piping. If this is a supply pipe, the wings will not be cooled sufficiently. For this reason, it is conceivable to wind the pipe in a coil shape to absorb the difference in thermal expansion, but this method is limited to the case where there is a large pipe space. In addition, piping is basically impossible in the rotating system path, and a large amount of leak is generated as a total amount at a point such as a mating surface between a wheel outer diameter end and a moving blade supply hole.

  As a sealing device in such a cooling path, a tube seal of EAGLE EG & G AERO-SPACE CO., LTD. Is well known, and includes a hollow cylindrical support and a spherical elastic body. Further, as related to this, for example, as described in JP-A-10-238301, an annular projection and a slit corresponding to a spherical elastic body are provided near the outer end of a thin hollow cylindrical body. It is known that both of them make use of the elasticity of the member to make an annular line contact with the seal hole to reduce the leak amount. They are mainly used in stationary fields and apply to radial flow in rotating fields.

JP-A-10-238301

  However, the use of such a conventional tube seal at a point in the rotating field that flows in the horizontal direction has the following problems. That is, due to the centrifugal force, the elastic seal device is pressed to the outside of the seal hole in the radial direction, and a part of the inside does not come into contact with the seal hole, and a leak occurs therefrom. Furthermore, the annular elastic body pressed outward causes fatigue failure due to the repeated action of the pressing force due to the vibration of the device. This not only causes a problem such as an increase in leakage, but also causes a part of the damaged elastic body sealing device to block the cooling passage of the moving blade, resulting in insufficient cooling of the moving blade which cannot secure an appropriate flow rate.

  In addition, these elastic seal devices are used in contact with the inner surface of the seal hole by utilizing elastic deformation, and the tolerance management of the devices becomes very complicated. That is, although the amount of leakage changes about twice in the order of several tens of μm, the manufacturing accuracy of the seal holes cannot correspond to this, and it is necessary to manufacture a seal device for each seal hole. If this management is not thoroughly carried out, problems such as an increase in the amount of leakage and an inability to assemble will occur due to the difference between the upper and lower limits in the respective manufacturing tolerances.

  SUMMARY OF THE INVENTION An object of the present invention is to improve the reliability of an elastic seal device installed in a horizontal flow path in a cooling path to a turbine rotor blade, which is a high-temperature cooled portion, while simplifying production management and assembling work. It is an object of the present invention to provide an elastic seal device having improved workability, a gas turbine using the same, and a method for operating the gas turbine.

(1) In order to achieve the above object, the present invention relates to an elastic seal device used for a cooling passage of a gas turbine, comprising: a support; elastic bodies provided at both ends of the support; And an annular projection provided at an outer end portion of the outer ring.
With this configuration, it is possible to improve the reliability, simplify the production management, and improve the workability of the assembling work.

(2) In order to achieve the above object, the present invention relates to an elastic seal device used for a cooling passage of a gas turbine, comprising: a support; elastic bodies provided at both ends of the support; And an annular projection provided at an outer end of the elastic body, wherein the annular projection has a diameter smaller than a maximum diameter of the elastic body.
With this configuration, it is possible to improve the reliability, simplify the production management, and improve the workability of the assembling work.

(3) In order to achieve the above object, the present invention relates to an elastic seal device used for a cooling passage of a gas turbine, comprising: a hollow support; and spherical elastic bodies installed at both ends of the hollow support. And an annular projection provided at the outer end of the hollow support.
With this configuration, it is possible to improve the reliability, simplify the production management, and improve the workability of the assembling work.

  (4) In order to achieve the above object, the present invention provides an elastic body having a support, an elastic body provided at both ends of the support, and an annular projection provided at an outer end of the support. The sealing device is provided in a cooling passage of a gas turbine.

  (5) In order to achieve the above object, the present invention provides a method for operating a gas turbine, comprising: a hollow support; an elastic body provided at both ends of the hollow support; and an outer end of the hollow support. An elastic seal device having an annular projection provided is provided in a cooling passage of the gas turbine so as to reduce a leak amount.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the reliability of an elastic body sealing apparatus, simplification of production management is achieved and workability | operativity of an assembling operation improves.

  Hereinafter, a configuration of a gas turbine according to an embodiment of the present invention will be described with reference to FIGS.

First, the overall configuration of the refrigerant recovery type gas turbine plant using the gas turbine according to the present embodiment, particularly the overall configuration from the flow of the working gas and the cooling air, will be described with reference to FIG.
FIG. 1 is a system configuration diagram showing an overall configuration of a refrigerant recovery type gas turbine plant using a gas turbine according to an embodiment of the present invention.

  The gas turbine 1 mainly includes a turbine 4, a compressor 2 connected to the turbine 4 to obtain compressed air for combustion, a combustor 3 for converting the compressed air into a high-temperature and high-pressure gas, and a generator 5. I have. The cooling air extracted from the compressor 2 passes through a precooler 6, a filter 7, and a boost compressor 8, and is branched from a cooling air supply path 10 into a stationary blade cooling air path 11a and a moving blade cooling air path 11b. It is supplied to the cooling unit. The air that has cooled the blades of the turbine 4 is recovered by the combustor 3 via the cooling air recovery path 12.

Next, a configuration of a main part of the gas turbine according to the present embodiment will be described with reference to FIG.
FIG. 2 is a sectional view of a main part of an upstream two-stage portion of the gas turbine according to one embodiment of the present invention.

  First, the cooling system of the first stage bucket 21a will be described.

  The cooling air supplied to the shaft end (not shown) of the turbine 4 is guided to the first stage supply chamber 15a via the center hole 24, and then supplied to the first stage blade supply passage 17a. The first-stage moving blade supply passage 17a communicates with a cooling path provided in the first-stage moving blade 21a (not shown), and further communicates with the first-stage moving blade collection passage 18a to form a first-stage wheel collection passage. It reaches the first-stage recovery chamber 16a via 19a. Thereafter, the cooling air is recovered to the combustor 3 through the cooling air recovery path 12 penetrating the first-stage wheel 22a and the second-stage wheel 22b.

  The contact surfaces of the first-stage supply chamber 15a and the first-stage bucket supply passage 17a and the contact surfaces of the first-stage bucket collection passage 18a and the first-stage wheel collection passage 19a respectively have first-stage supply elasticity. A body seal 30a and a first stage recovery elastic seal 31a are provided. The first-stage supply elastic seal 30a is installed for the flow in the radial direction, but the first-stage recovery elastic seal 31a is provided in a horizontal flow field. Reference numeral 20a is a first stage stationary blade.

  Similarly, in the cooling system of the second stage rotor blade 21b, the cooling air supplied to the shaft end (not shown) of the turbine 4 is guided to the second stage supply chamber 15b through the center hole 24, It is supplied to the step rotor blade supply passage 17b. The second-stage moving blade supply passage 17b communicates with a cooling path provided in the second-stage moving blade 21b (not shown), and further communicates with the second-stage moving blade recovery passage 18b to form a second-stage wheel recovery passage. It reaches the second-stage recovery chamber 16b via 19b. Then, the second-stage wheel 22b and the cooling air recovery path 12 penetrating the second-stage wheel 22b are directed to the combustor 3.

  The contact surfaces of the second-stage supply chamber 15b and the second-stage blade supply passage 17b and the contact surfaces of the second-stage blade recovery passage 18b and the second-stage wheel collection passage 19b are provided with second-stage supply elasticity, respectively. A body seal 30b and a second stage recovery elastic seal 31b are provided. The second-stage supply elastic seal 30b is provided for radial flow, but the second-stage recovery elastic seal 31b is provided in a horizontal flow field. Reference numeral 20b is a second stage stationary blade.

Next, the configuration and the assembled state of the spherical elastic seal used in the gas turbine according to the present embodiment will be described with reference to FIG.
FIG. 3 is a cross-sectional view showing a configuration of a recovery elastic seal used in the gas turbine according to the embodiment of the present invention and a state at the time of installation.

The first-stage recovery elastic seal 31a includes a hollow support 34 and spherical elastic bodies 35 at both ends. The diameter of the annular projection 36 provided at the outer end of the hollow support 34 is D2, the maximum diameter of the spherical elastic body 35 when opened is D1, and the blade-side seal hole 38 provided in the first stage blade 21a is When the hole diameter is Dh, the relationship is D1>Dh> D2. Further, three slits 37 extending from the outer end of the spherical elastic body 35 to the inside from the position P of the maximum diameter D1 are formed. The spherical elastic body 35 incorporated in the rotor blade side seal hole 38 changes its maximum diameter to Dh due to its rigidity, and comes into contact with the rotor blade side seal hole 38 surface. At this time, there is a gap of (Dh-D2) / 2 in the circumferential direction between the blade-side seal hole 38 and the annular projection 36, but (D1-Dh) / 2> (Dh-D2) / There are two relationships.
The above description is about the cooling system of the first stage rotor blade, but the same applies to the second stage supply elastic seal 30b and the second stage recovery elastic seal 31b of the two stage rotor cooling system. is there. The difference between the supply elastic seal and the recovery elastic seal is that the flow of the cooling air is in the radius and the horizontal direction, and the shapes are the same.

  With the above-described configuration, first, when the elastic body sealing devices 31a and 31b are attached to the moving blade side seal holes 38 of the first stage moving blade recovery passage 18a, the spring constant (spring constant ( = Pressing force / deformation amount of the spherical elastic body) is reduced to 1/10 or less, and mounting in the seal hole is possible with a relatively small pressing force.

  The high-temperature and high-pressure working gas generated in the compressor 2 and the combustor 3 during the operation of the gas turbine 1 has a pressure of about 20 ata and a temperature of about 1400 ° C., and the first stage stationary blades 20 a and the first stage blades 21 a inside the turbine. First, the pressure and temperature are reduced while performing turbine work in each stage, and the final stage blade is discharged at about 600 ° C. At this time, the generator 5 directly connected to the gas turbine 1 rotates to obtain electric power.

  Since the turbine blades are exposed to high-temperature gas, a part of the high-pressure air obtained by the compressor 2 is extracted and used as cooling air. However, the temperature of the extracted air in the compressor 2 is as high as about 500 ° C. Therefore, it is led to the pre-cooler 6 to reduce the temperature to about 150 ° C. Further, the supply pressure for returning the extracted air as cooling air to the combustor 2 needs to be set so that the recovery pressure is larger than 20 ata in consideration of the pressure loss in the piping and the portion to be cooled. It is. For this reason, the bleed air whose temperature has been reduced by the precooler 6 is guided to the boost compressor 8, and the pressure is increased to about 35 ata. The cooling air is branched into a stationary blade side and a moving blade side, and one of the cooling air is used as a moving blade cooling air path 11b to exchange heat inside the blades of the moving blades 21a and 21b, thereby lowering the metal temperature below the allowable temperature of the blade material. I do. Thereafter, the gas is recovered to the combustor 3 along the cooling air recovery path 12 to increase the turbine output.

Next, the operation of the spherical elastic seal used in the gas turbine according to the present embodiment in the operating state will be described with reference to FIG.
FIG. 4 is a cross-sectional view showing an operating state of the recovery elastic seal used in the gas turbine according to the embodiment of the present invention.

  During gas turbine operation, the first-stage recovery elastic seal 31a is in a strong centrifugal field and receives a centrifugal force radially outward. However, with the increase in the rotation speed, the annular projection 36 hits the outer inner surfaces of the rotor blade side seal hole 38 and the spacer side seal hole 39, so that it does not receive all the centrifugal force. In addition, since the spherical elastic body 35 is not pressed below Dh with respect to the center line of the hollow support 34 of the seal hole, the bending stress applied to the weld between the hollow support 34 and the spherical elastic body 35 is reduced. Is also smaller. Of course, in this vicinity, point P is in line contact with the seal hole. On the other hand, the inner side in the radial direction is apparently lifted, but from the relationship of (D1−Dh) / 2> (Dh−D2) / 2, the spherical elastic body 35 separates from the seal hole surface. Is not. That is, line contact at P continues over the entire circumference, and leakage from the first-stage bucket recovery passage 18 and the first-stage wheel collection passage 19a to the wheel space 25 and the second-stage collection chamber 16b is prevented. it can.

As described above, in the elastic body sealing device having the annular protrusion according to the present embodiment, the provision of the annular protrusion at the outer end of the support body not only reduces the amount of leakage but also reduces the centrifugal force acting on the spherical elastic body. By reducing the stress level and reducing the stress level, a highly reliable refrigerant recovery type gas turbine that prevents damage and destruction can be provided, and its effect can be sufficiently exerted.
In addition, by providing a slit in the spherical elastic body, the rigidity can be reduced, so that it is possible to respond to the production of the elastic seal device with one manufacturing tolerance, eliminating the complexity of production management and comparing Since the target can be mounted with a small force, workability can be improved. This slit length affects the rigidity of the spherical elastic body. Since the spring constant changes with a square of the slit length, the effect is hardly expected if it is short. It is natural that it is meaningless to make the outer end longer than the point P. In order to weaken the rigidity of the spherical elastic body, it is necessary to provide a slit from the point P to the inside.
Here, it is conceivable that the reduction in rigidity due to the provision of the slit may cause a leak as well as the area of the slit itself. However, this embodiment aims at securing the minimum rigidity, and has an advantage in that the adverse effects due to the extra rigidity can be eliminated. Incidentally, it has been experimentally confirmed that the leak is close to zero if the squeezing is about 40 μm in the three 70 μm slits made of stainless steel as the spherical elastic body.

In the above description, the first-stage moving blade has been described. However, if the present invention is applied not only to the cooling passage of the rear-stage moving blade but also to a sealing device at a position where the flow in the rotating field is horizontal, a greater effect can be obtained. Can be expected.
Further, the present invention can be applied to a gas turbine of a conventional open cooling system or a gas turbine of a different type of refrigerant.

FIG. 1 is a system configuration diagram illustrating an overall configuration of a refrigerant recovery type gas turbine plant using a gas turbine according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a main part of an upstream two-stage portion of the gas turbine according to the embodiment of the present invention. FIG. 1 is a cross-sectional view showing a configuration of a recovery elastic seal used in a gas turbine according to an embodiment of the present invention and a state at the time of installation. FIG. 2 is a cross-sectional view illustrating a state in which the recovery elastic seal used in the gas turbine according to the embodiment of the present invention is in an operating state.

Explanation of reference numerals

1. Gas turbine
2. Compressor 3. Combustor
4 Turbine 5 Generator
6 Pre-cooler 7 Filter
8 ... Boost compressor
11b: Blade cooling air path
12: Cooling air recovery path
15a: First-stage supply chamber
16a: First-stage recovery chamber
17a: 1st stage rotor blade supply passage
18a: First-stage bucket recovery passage 19a: First-stage wheel collection passage 30a: First-stage supply elastic seal
31a: first-stage recovery elastic seal 34: hollow support
35 spherical elastic body 36 annular projection
37 ... slit 38 ... rotor blade side seal hole
39: Spacer side seal hole

Claims (5)

An elastic seal device used for a cooling passage of a gas turbine,
A support,
Elastic bodies installed at both ends of the support,
An elastic body sealing device comprising: an annular projection provided at an outer end of the support. An elastic seal device used for a cooling passage of a gas turbine,
A support,
Elastic bodies installed at both ends of the support,
An annular projection provided at an outer end of the support,
An elastic body sealing device, wherein the annular projection has a diameter smaller than a maximum diameter of the elastic body. An elastic seal device used for a cooling passage of a gas turbine,
A hollow support,
A spherical elastic body installed at both ends of the hollow support,
An elastic projection provided at an outer end of the hollow support.   A gas turbine in which an elastic seal device having a support, an elastic body provided at both ends of the support, and an annular projection provided at an outer end of the support is provided in a cooling passage. In the method of operating a gas turbine,
A hollow body, an elastic body provided at both ends of the hollow support, and an elastic body sealing device having an annular projection provided at an outer end of the hollow support are provided in a cooling passage of the gas turbine. A method of operating a gas turbine that reduces the amount of leakage by installing it.

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