JP3349056B2 - Refrigerant recovery type gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant recovery type gas turbine, and more particularly to a joint between a plurality of disks having blades implanted on the outer periphery thereof and a plurality of spacers interposed between the disks. Further, the present invention relates to a refrigerant recovery type gas turbine provided with a refrigerant flow passage for cooling a moving blade, that is, a so-called closed cooling type gas turbine.

[0002]

2. Description of the Related Art A moving blade of a gas turbine generally used in the related art is cooled by air supplied through a rotor. A part of the compressed air for combustion is used as an air source, and after cooling, it is discharged into a passage of a combustion gas (hereinafter, referred to as a gas path).

In order to improve turbine efficiency, it is necessary to increase the temperature of the combustion gas (turbine inlet temperature). However, increasing the temperature inevitably increases the consumption of cooling air, and this air is released into the gas path, which not only lowers the temperature of the combustion gas, but also disturbs the gas flow and causes In order to deteriorate the performance, there is a limit to the improvement of the turbine efficiency by increasing the temperature of the combustion gas.

In order to further improve the performance, it is necessary to recover the air used for cooling the blades in order to solve the above-mentioned problems. For this reason, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Unexamined Patent Publication No. 3809, a supply / recovery path for the refrigerant is formed by piping inside the rotor, and a supply of the refrigerant is provided by piercing the inside of the rotor component as disclosed in Japanese Patent Application Laid-Open No. 3-275946. A method for configuring a collection path has been proposed.

[0005]

However, since the rotor rotates at a high speed, it is better to simplify the structure as much as possible.
In order to avoid stress concentration, it is desirable to avoid the screw fastening structure and the like as much as possible. Further, in a gas turbine having a working gas temperature of 1500 ° C. or more, the temperature of the refrigerant is reduced by cooling the blades with air, although it varies depending on the type of the refrigerant.
It rises more than 50 degrees. For this reason, the recovery path is exposed to an environment at a temperature 250 degrees higher than the supply path, and depending on the arrangement of the flow path formed by perforating the rotor member, a great deal of thermal stress may be generated.

The present invention has been made in view of the foregoing, and an object of the present invention is to reduce heat transfer from a refrigerant to a member, that is, heat transfer to a disk and a spacer portion interposed between the disks. It is an object of the present invention to provide a refrigerant recovery type gas turbine of this type that generates little thermal stress on a disk and a spacer.

[0007]

That is, according to the present invention, a plurality of disks having rotor blades implanted on the outer periphery thereof and arranged in parallel in the axial direction, and a plurality of spacers interposed between the disks are provided. In a refrigerant recovery type gas turbine, which is formed so as to allow a refrigerant for cooling a rotor blade to flow through a joint between the spacer and the disk, an outer peripheral side wall surface is provided between the joint between the disk and the spacer. A heat shield duct extending in the radial direction is provided, and a coolant for cooling the moving blades is formed to flow through the heat shield duct to achieve an intended purpose. .

In this case, a cylindrical rib is provided at the end of the heat shield duct on the reaction blade side, and this rib is inserted into a hole formed in the disk so as to support the centrifugal load of the heat shield duct. It was done.

As a second means, one end is opened on the outer peripheral side from the joint portion between the disk and the spacer, and the other end is formed so as to communicate with the cooling passage of the moving blade, and an L-shaped supply hole and a recovery hole are formed. In a refrigerant recovery type gas turbine having a hole, a fin is provided on a side surface between a joint of a spacer adjacent to a disk and a seal land on an outer periphery, and the fin partitions a cavity between the disk and the spacer into two chambers.
Between the inside of the fin and the junction, while forming a cavity of a narrow space that opens the outlet of the above-mentioned collection hole,
A space is provided between a side end of the seal land and a side surface of the disk so that a space outside the fin communicates with a wheel space formed outside the seal land.

Further, as a third means, in a refrigerant recovery type gas turbine having a recovery flow path extending in the radial direction between the joining surfaces of the disk and the spacer, in the outer periphery of the disk,
A recovery hole is formed from the cooling flow path of the rotor blade to the side surface, and a fin is provided on the side surface between the joint of the spacer adjacent to the open surface and the seal land on the outer periphery to form two cavities between the disk and the spacer. The chamber inside the fin communicates with the collection flow path between the joining surfaces, and the collection hole and the chamber inside the fin are connected by a conduit.

In this case, a small-diameter hole may be formed for communicating the chamber outside the fin with the supply flow path provided on the opposite side of the disk.

By mounting the heat shield duct in the slit flow channel by the first means, a gap is formed between the wall surface of the slit and the heat shield duct, and this gap shields heat transfer from the refrigerant to the rotor constituent members. Therefore, the temperature gradient caused by the temperature difference between the supply and the recovered refrigerant is reduced, and the thermal stress is reduced.

Further, by providing a gap between the seal land on the outer periphery of the spacer and the side surface of the disk by the second means and communicating with the outer foil space, both sides of the outer peripheral portion of the disk can be set to a similar heat transfer environment. In particular, the thermal stress at the outer peripheral portion of the disk can be reduced.

Further, as a third means, since the high-temperature refrigerant is recovered from the outer periphery of the disk to the slit of the joint by a pipe without passing through the inside of the disk, one surface of the disk becomes substantially insulated. The temperature gradient between the disk side surfaces becomes gentler, and the thermal stress is further reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a cross-sectional structure of an upper half of a closed air-cooled gas turbine according to the present invention, in which a casing 1, a compressor 2, a combustor 3, and a stationary blade 4 of a turbine section are disposed. , A rotor blade 5 and a turbine rotor 6.

The turbine rotor 6 is composed of four disks 11, 12, 13, and 14 having blades implanted on the outer periphery, spacers 15, 16, and 17, and a stub shaft 18. It is fastened integrally with the rotor of the compressor 2 via the piece 19. One end is a bearing 20
Supported by In such a configuration, the high-temperature, high-pressure combustion gas generated in the combustor flows through the gas path 10 to rotate the rotor 6 supported by the bearing 20 to generate power.

The blades are exposed to hot combustion gases and the heat load depends on the gas temperature at the combustor outlet. For this reason, a cooling flow path is formed inside the moving blades of the first to third stages in accordance with the heat load based on the difference between the gas temperature and the heat-resistant temperature of the outer surface. It is designed to cool.

For this reason, in the rotor, as shown by an arrow 80, a supply passage for guiding cooling air from the supply port 21 at the shaft end to the first and second stages of moving blades is provided with a shaft inner hole and a stacking joint. Hole 22, slit 2 formed in the radial direction between joining surfaces
3, a cavity 26 formed by projecting the fins 24 or 25, and an L-shaped hole 27 formed in the first and second disc webs.

The air after cooling is, as indicated by arrow 81,
The holes 30 formed in the webs of the first-stage and second-stage disks from the root of the rotor blade 5, the fins 25 of the spacer 15 and the cavity 31 formed between the disks, and the slits 32 merge at the holes 33 at the joint A, and the outlet is formed. From 34, it is collected in the combustion chamber 35.

The radial positions of the fins 24 and 25 forming the cavities 26 and 31 are formed so as to be as narrow as possible and have the same radial position within a range that does not hinder the supply and recovery of the cooling air. . Further, a gap of a fixed width is provided between the labyrinth seal land and the disk, and a wheel space on the side of the diaphragm supporting the stationary blade extends to the fin side wall.

FIG. 2 is an enlarged view of a portion X in FIG. 1. The supply hole 22 and the recovery hole 33 at the stacking joint are shown in FIG.
Inside, a heat shield tube 40 supported on the inner wall of the hole via a rib 41 is mounted, and is heat shielded by forming a gap 42 between the outer wall of the tube other than the rib 41 and the inner wall of the hole. Also in the supply and recovery slits 23 and 32, a heat shield duct 50 for heat shield utilizing a gap is used.
Is installed.

FIG. 3 shows the appearance of the heat shield duct 50. A rib 53 for forming a gap is formed on a side surface of the duct 51, and a cylindrical rib 54 is provided at an end of the duct. The rib portion is inserted into the supply hole 22 or the recovery hole 33 to support a centrifugal load.

FIG. 4 is a view taken in the direction of arrows Y--Y in FIG. 1, and shows the arrangement of the supply and recovery passages as viewed from the side of the disk. As can be seen from FIG. Hole 23 has a stacking bolt hole 60.
Are alternately arranged at intermediate positions. Also, the recovery air merges with the recovery slit from a plurality of holes, and it is necessary to secure an area where the cooling air flows at a flow rate corresponding to the number of step blades / slit as the flow path cross-sectional area.

On the other hand, as shown by an arrow 82, air extracted from the compressor 2 is supplied to the three-stage rotor blade at the center of the rotor formed by the inner hole 61 of the distant piece 19, the disk center hole 62 and the like. It is supplied via a passage. Although the temperature of the bleed air varies depending on the position of the bleed air from the compressor, it is selected at a stage position that is at least equal to or higher than the average temperature of the cooling air supply temperature of the blades and the recovery temperature.

On the other hand, on the outer peripheral side of the rotor, the three-stage rotor blade also branches off from the supply hole 22 at the joint, and
Although the cooled air can be recovered in the combustion chamber 35 in the same manner as in the stage, the purpose of forming the independent supply passage passing through the center of the rotor is to increase the temperature rising speed of the center of the disk at the time of starting the turbine. This is to reduce the steady thermal stress.

As an example, when the gas temperature at the combustor outlet is 15
Assuming that the temperature is 00 ° C., the first stage blade is exposed to gas at approximately 1300 ° C., the second stage blade is exposed to gas at 1050 ° C., and the third stage blade is exposed to gas at 900 ° C ..
Rises 50 degrees. Since the allowable temperature of the rotor is limited to 500 ° C. even for a material having high heat resistance, the supply temperature of the cooling air needs to be 250 ° C. or less.

Since the supply holes 22 and the recovery holes 33 are alternately arranged in the circumferential direction at the stacking joint of the first-stage and second-stage disks, the temperature of this portion is set to a substantially intermediate temperature between the supply air and the recovery air. Supply temperature is 2
When the temperature is set to 50 ° C., the temperature of the junction becomes about 375 ° C. Therefore, air with the same temperature or higher is extracted from the compressor and
By supplying to the step rotor, the temperature at the center of the disk becomes higher than the temperature of the joint during normal operation.

Since the centrifugal stress acting on the central portion of the disk is higher than that on the outer peripheral side due to the difference in thermal expansion, the cooling system for extracting air for cooling the three-stage moving blades from the compressor. Is effective in reducing the stress during steady operation.

At the joint from the first stage disk to the second stage disk, supply holes 22 and recovery holes 33 arranged in the circumferential direction are provided.
Are alternately flowed at 250 ° C. and 500 ° C., and slits 23 and 32 formed on both sides of the
Although the air having a temperature difference of a certain degree flows, the heat shield pipe 40 and the heat shield duct 5 are provided in the supply, recovery holes and slits as described above.
0, and these heat shields have a heat transfer amount of 10 in comparison with the case where they are not installed even if heat conduction from the ribs is considered.
It is estimated that the temperature gradient is greatly smoothed because the effect is reduced to one-half.

A heat source from the recovered air is not loaded from the spacer 16 at the intermediate stage to the joint of the stub shaft 18, and the heat is generated during startup and steady operation because the heat shield tube 40 is installed in the supply hole 22. Thermal stress is small.

On the other hand, focusing on the outer peripheral portion of the disk, especially in the webs of the first stage and the second stage, the temperature difference is formed in supply and recovery holes 27 and 30 formed in an L-shape at a relatively short distance. Although the air at 250 degrees turns and flows, the outer wall surface, except for the narrow area of the cavities 26 and 31, extends the foil space on the side of the diaphragm to the fin position, so that both sides are in a thermally conductive environment. Has become. Further, since the operation can be performed from the stationary side, it is possible to adjust the environmental temperature as needed. Therefore, considering that the centrifugal stress acting on the outer peripheral side of the disk is less than half that of the central side, the heat transfer environment on the side surface is optimized to generate between the internal supply and recovery holes. Thermal stress can be reduced and kept within the allowable stress.

FIG. 5 shows another embodiment of the supply and recovery structure of the disk web. In this embodiment, instead of the L-shaped supply / recovery holes formed inside the above-mentioned first and second stage disks, a recovery path is constituted by a conduit 70 outside the disk. That is, while the inclined recovery hole 71 is formed in the outer peripheral portion of the disk, the two cavities 74 and 75 partitioned by the fin 73 are formed in the outer peripheral side of the spacer 72.
To form The inner cavity 75 communicates with the cooling air recovery slit 32, and connects the cavity 75 and the recovery hole 71 with a pipe 70 to recover cooling air from the rotor blades.

The inlet end of the conduit 70 is pressed against the outer peripheral seal land 76 of the spacer 72 and the side surface of the disk outer periphery, and the other end is inserted and supported in a hole formed in a fin 73 formed on the side surface. . At the time of assembling, it is mounted on the spacer side and fixed when joining to the disk.

On the other hand, on the supply side, a fin 77 formed in a distant piece was extended to the outer peripheral side to form a cavity 78 having a wide space.

By arranging the cooling path as described above, the disk web portion is cooled on one side by the supply air at 250 ° C., while most of the opposite wall surface slightly leaks from the pipe connection. It is heated by the recovered air and is almost insulated. For this reason, the temperature gradient between both side surfaces is small, and the generation of heat forward stress is small.

A small diameter hole 79 is formed in the outer peripheral portion of the disk from the cavity 78 to the cavity 74 to supply air to the cavity 74 to a degree that does not affect the efficiency of the gas turbine. Since the environment is close to the supply temperature, the effect of reducing the thermal stress is more remarkably exhibited. By setting the cavity 74 in a low-temperature environment, the temperature of the outer peripheral portion of the spacer is reduced, which is also effective in reducing the stress of the spacer.

As described above, in the refrigerant recovery type gas turbine formed as described above, the temperature gradient formed inside the rotor due to the recovery of the refrigerant is alleviated, thereby generating the rotor constituent members. Thermal stress is reduced,
By putting a closed cooling type gas turbine into practical use, an efficient gas turbine can be obtained.

[0038]

As described above, according to the present invention, the heat transfer from the refrigerant to the member, that is, the heat transfer to the disc and the spacer portion interposed between the discs is reduced, whereby the disc and the spacer portion are reduced. This type of refrigerant recovery type gas turbine with less thermal stress can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a refrigerant recovery type gas turbine of the present invention.

FIG. 2 is an enlarged view of a part X in FIG. 1;

FIG. 3 is an external view of a heat shield duct used in the refrigerant recovery type gas turbine of the present invention.

FIG. 4 is a view of the refrigerant recovery type gas turbine of the present invention as viewed from a disk side surface.

FIG. 5 is a longitudinal sectional side view showing another embodiment of the refrigerant recovery type gas turbine of the present invention.

[Explanation of symbols]

5: rotor blade, 6: turbine rotor, 11, 12: disk, 15, 16: spacer, 23, 32: slit, 2
4, 25 fins, 26, 31, 74, 75 cavities, 27 L-shaped holes, 33 recovery holes, 40 heat shield tubes, 4
Reference numerals 1, 53: ribs, 50: heat shield duct, 54: cylindrical ribs, 56: labyrinth seal land, 57: wheel space, 70: pipeline, 71: collection hole, 79: hole.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Higuchi 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Power & Electricity Development Division, Hitachi, Ltd. (72) Inventor Takashi Ikeguchi Omikamachi, Hitachi City, Ibaraki Prefecture No.2-1, Hitachi, Ltd. Power and Electricity Development Division (72) Inventor Kazuhiko Kawaike 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Power and Electricity Development Division (56) References Special JP-A-7-189739 (JP, A) JP-A-9-13902 (JP, A) JP-A-7-26903 (JP, A) JP-A 8-277725 (JP, A) JP-A-54-13809 JP, A) JP-A-3-275946 (JP, A) JP-A-10-205302 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02C 7/16 F01D 5/08

Claims (5)

(57) [Claims] A plurality of disks having rotor blades implanted on an outer peripheral portion thereof and arranged in parallel in an axial direction; and a plurality of spacers interposed between the disks. In a refrigerant recovery type gas turbine formed so as to allow a refrigerant for cooling a rotor blade to flow through a joint, a rib is provided on an outer peripheral side wall between joints between the disk and the spacer, and a radial direction is provided. A refrigerant recovery type gas turbine, characterized in that a heat shield duct extending to the heat shield duct is provided and a coolant for cooling the moving blades is circulated in the heat shield duct. 2. The heat shield duct is provided with a cylindrical rib at an end thereof on a reaction blade side, and the rib is inserted into a hole formed in the disk to support a centrifugal load of the heat shield duct. Item 2. A refrigerant recovery type gas turbine according to Item 1. 3. A cooling system for supplying and recovering a blade cooling medium into a turbine rotor including a plurality of disks having blades implanted on an outer periphery thereof and a plurality of spacers interposed between the disks, As a part of the flow path constituting this cooling system, one end is opened at a position close to the joining part on the outer peripheral side from the joining part of the disk and the spacer, and the other end is connected to the cooling passage of the moving blade. In a refrigerant recovery type gas turbine having substantially the same number of L-shaped supply holes and recovery holes as the number of blades formed in the above, a fin is provided on a side surface between a joint portion of a spacer adjacent to the disk and a seal land on an outer periphery. The cavity between the disk and the spacer is divided into two chambers by the above method, and a cavity having a narrow space for opening the outlet of the recovery hole is formed between the inside of the fin and the joint portion. Said a side edge provided with a gap between the side surface of the disc, the refrigerant recovery type gas turbine, characterized in that said outside the fin space is allowed to communicate with the wheel space formed outside the seal land. 4. A cooling system for supplying and recovering a blade cooling medium into a turbine rotor comprising a plurality of disks having blades implanted on an outer periphery thereof and a plurality of spacers interposed between the disks, In a refrigerant recovery type gas turbine having a recovery flow path formed in a radial direction between a joining surface of the disk and the spacer as a part of a flow path constituting the cooling system, the rotor blade is provided on an outer peripheral portion of the disk. A recovery hole communicating with the side surface from the cooling flow path is formed, and fins are provided on the side surface between the joint portion of the spacer adjacent to the open surface and the seal land on the outer periphery to partition the cavity between the disk and the spacer into two chambers, The refrigerant recovery type gas is characterized in that the chamber inside the fin communicates with the recovery flow path between the joining surfaces, and the recovery hole and the chamber inside the fin are connected by a conduit. Turbine. 5. The refrigerant recovery type gas turbine according to claim 4, wherein a chamber outside the fins and a supply passage formed on the opposite side of the disk are formed to communicate with each other through a small-diameter hole.