JP2011137390A - Gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas turbine performing turndown operation with low emission by a simple system while ensuring reliability of the gas turbine. <P>SOLUTION: This gas turbine 1 includes: a compressor 2 compressing air used for combustion; a combustion section 3 injecting fuel to the compressed air in order to perform combustion and generating high-temperature combustion gas; a turbine section 4 rotatively driven by the combustion gas; and a moving blade cooling system 6 bleeding a part of the compressed air as cooling air and introducing the cooling air to the insides of moving blades belonging to a plurality of stages composing the turbine section 4. The moving blade cooling system 6 is provided with an adjustment section 63 adjusting the flow rate of the cooling air flowing in the inside. The flow rate of the cooling air flowing in the moving blade cooling system 6 during operation at a load lower than the full load is higher than the flow rate of the cooling air during operation at the full load. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas turbine, and more particularly to a gas turbine capable of turndown operation (partial load operation or low load operation).

  In general, in an internal combustion engine such as a gas turbine, an upper limit value of substances such as carbon monoxide (CO) and hydrocarbon (HC) contained in exhaust gas is determined by laws and regulations aimed at preventing air pollution and the like. Further, from the viewpoint of environmental protection, which is being emphasized in recent years, it is desired to further reduce carbon monoxide and the like contained in exhaust gas (lower emission).

  By the way, when the gas turbine is operated at a rated load, the amount of substances such as carbon monoxide contained in the exhaust gas is less than the above upper limit value and is a low value (low emission). However, when the gas turbine is in partial load operation (hereinafter referred to as “turn-down operation”), which is a load lower than the rated load, the intake flow rate of the gas turbine remains the same and the fuel flow rate is reduced. The combustion temperature in the combustor decreases, and as a result, a large amount of unburned substances such as carbon monoxide and hydrocarbons are generated. When these substances were released into the exhaust gas, the above upper limit value was sometimes exceeded.

  However, there is a desire to perform a gas turbine turn-down operation in order to operate a flexible power plant according to power demand. For this reason, various techniques have been proposed for performing a turn-down operation of the gas turbine while maintaining a low amount of substances such as carbon monoxide contained in the exhaust of the gas turbine (low emission).

  That is, the compressed air compressed by the compressor of the gas turbine is extracted as cooling air, and the cooling air is excessively supplied to the stationary blade system and the moving blade system of the turbine, thereby performing the turn-down operation while maintaining low emission. Techniques have been proposed (see, for example, Patent Documents 1 to 3).

  Alternatively, a technique has been proposed in which turn-down operation is performed while maintaining low emissions by using anti-icing that extracts air compressed by a compressor and guides it to the upstream side of the inlet guide vanes (for example, patents). Reference 4).

JP 2007-182883 A JP 2009-062981 A JP 2009-103125 A JP 2009-052548 A

  However, when the cooling air is introduced into the turbine stationary blade system as described above, the cooling system belonging to a plurality of stages is prevented in order to prevent a decrease in reliability due to excessive cooling of only the blades of a specific stage. There was a problem that it was necessary to supply cooling air to each. In other words, there is a problem that it is necessary to provide a plurality of pipes that connect the cooling air system.

  In addition, when air (chamber air) that has been pressurized by the compressor and discharged into the turbine casing is extracted and supplied to the stationary blade system as an excessive amount of cooling air, the air is newly supplied from the turbine casing. Instead of providing the casing bleed piping, as shown in FIG. 8, it is economical to provide a bypass flow path 365 from the casing bleed piping 361 to the stationary blade cooling air system 307 according to the existing moving blade cooling air system 306. Is. However, if such a system is used, a large amount of air flows in a part of the existing rotor blade cooling system 306 and the like, so the pressure loss generated there reduces the cooling air supply pressure to the rotor blades, There is a possibility of burning the wing.

  That is, generally, the supply pressure of the cooling air is set to be higher than the pressure of the main flow flowing around the blade, and the blade is utilized by utilizing the ratio of the pressure (back flow margin (hereinafter referred to as “BFM”)). The cooling air that has cooled the air is discharged into the mainstream. However, if the supply pressure of the cooling air is lower than the pressure of the mainstream that flows around the blades, there is a possibility that the BFM is insufficient and the high-temperature mainstream gas flows into the blades, and the blades are burned by the mainstream gas. .

The above problem can be avoided by excessively supplying cooling air not to the stationary blade cooling air system 307 but to the moving blade cooling air system 306 having moving blades belonging to a plurality of stages.
Generally, the moving blade cooling air system 306 is configured to branch into moving blades belonging to a plurality of stages inside the turbine section, as shown in FIG. Even if the cooling air is excessively supplied to the moving blade cooling air system 306, the cooling air is not excessively supplied to the moving blades belonging to a specific stage, and the moving blades belonging to a plurality of stages Distributed. That is, it is possible to avoid a decrease in reliability that occurs when cooling air is excessively supplied to a specific stage.

Furthermore, if the cooling air is excessively supplied to the moving blade cooling air system 306, it becomes easy to secure the BFM, so that the burning of the moving blade due to the shortage of BFM hardly occurs.
On the other hand, although the absolute value of the supply pressure of the cooling air to the stationary blade cooling air system 307 is reduced, the ratio of the pressures of each part in the gas turbine is kept almost the same regardless of whether or not the cooling air is bypassed. It will remain leaning. Therefore, as in the case of the moving blade, the stationary blade is less likely to be burned out due to the lack of BFM.

Here, generally, the stationary blade cooling air system 307 is designed to extract the amount of passenger compartment air necessary for cooling the stationary blade system as cooling air. In other words, it is not designed to flow air for cooling the moving blade system in addition to the air for cooling the stationary blade system.
Therefore, in order to supply cooling air to the moving blade system excessively via the stationary blade cooling air system 307, the cabin air is further pressurized and pumped to the stationary blade cooling air system 307 and the moving blade cooling air system 306. There is a problem that it is necessary to provide a means for performing such as a boost compressor.

  Further, the method of performing turn-down operation while maintaining low emission by using only anti-icing has a problem that there is a limit to the amount of load reduction during turn-down operation.

  The present invention has been made to solve the above-described problems, and provides a gas turbine capable of performing a low emission turndown operation with a simple system while ensuring the reliability of the gas turbine. With the goal.

In order to achieve the above object, the present invention provides the following means.
The gas turbine of the present invention includes a compressor that compresses air used for combustion, a combustion section that injects fuel into the compressed air to burn it, and generates a high-temperature combustion gas, and is rotationally driven by the combustion gas. A turbine section that is configured to extract a part of the compressed air as cooling air, and a blade cooling system that guides the cooling air to the inside of the blades belonging to a plurality of stages constituting the turbine section, The moving blade cooling system is provided with an adjustment unit that adjusts the flow rate of the cooling air flowing through the moving blade cooling system, and flows through the moving blade cooling system during operation at a load lower than a full load. The flow rate of the cooling air is larger than the flow rate of the cooling air during operation at the full load.

According to the present invention, when the gas turbine is operated at a load lower than the full load, that is, when the gas turbine is turned down, the flow rate of the cooling air flowing through the rotor blade cooling system is The flow rate is higher than when the load is operated.
As a result, the ratio of the cooling air flow rate to the intake flow rate of the gas turbine increases, and the air flow rate flowing from the compressor into the combustor decreases. Therefore, the combustion temperature in the combustor becomes high, and it is possible to perform the turn-down operation while maintaining a state where the amount of substances such as carbon monoxide contained in the exhaust of the gas turbine is small (low emission).

On the other hand, at the time of turndown operation, the flow rate of the cooling air flowing through the rotor blade cooling system is increased more than the flow rate at the time of full load operation. Therefore, cooling air can be supplied to the moving blades during the turndown operation without arranging a boost compressor in the moving blade cooling system.
Furthermore, since the cooling air that cools the moving blades during turn-down operation is supplied to the moving blades belonging to a plurality of stages, only the moving blades belonging to a specific stage (for example, one-stage moving blades) may be excessively cooled. This prevents the blade reliability from being lowered. Furthermore, since the supply pressure drop of the cooling air to the stationary blade is suppressed, the problem of BFM decrease in the stationary blade can be avoided, and the occurrence of burning of the stationary blade can be suppressed.

  In the above invention, the moving blade cooling system is provided with a pre-swirl unit that applies a flow velocity component that rotates in the rotation direction of the moving blade to the cooling air, and the flow path of the cooling air in the pre-swivel unit It is desirable that the throat area with the smallest cross-sectional area be larger than the flow-path cross-sectional area determined based on the flow rate of the cooling air flowing through the moving blade cooling system during operation at the full load.

  According to the present invention, the throat area in the pre-swirling portion is made larger than the flow path cross-sectional area determined based on the flow rate of the cooling air flowing through the moving blade cooling system when the gas turbine is operating at full load. Thus, the flow rate of the cooling air supplied to the moving blades during the turndown operation can be surely increased.

  For example, if the throat area is equivalent to the cross-sectional area of the flow passage determined based on the full load operation, the throat area will be reduced even if the flow rate of cooling air supplied to the rotor blade cooling system is increased. It becomes a throttle, and the flow rate of the cooling air supplied to the moving blade cannot be effectively increased. In other words, the influence of the throat area on the flow rate of the cooling air supplied to the moving blade is large. Therefore, by increasing the throat area, it is possible to reliably increase the flow rate of the cooling air supplied to the moving blades during the turndown operation.

  In the above invention, the moving blade cooling system is provided with a pre-swirl unit that applies a swirling component that rotates in the rotation direction of the moving blade to the cooling air, and the flow path of the cooling air in the pre-swirling unit It is also desirable that the throat area with the smallest area be controlled in accordance with the operating state.

According to the present invention, the flow rate of the cooling air supplied to the moving blades via the moving blade cooling system can be adjusted by changing the throat area according to the operating state of the gas turbine.
Specifically, when the turbine is operating at full load, the throat area can be changed in accordance with the appropriate cooling air flow rate at each gas turbine output, as in the case of the turndown operation. For this reason, it is possible to suppress the performance degradation of the gas turbine during full load operation and to maintain low emission even during turndown operation.

  For example, when the pre-swivel part has a configuration in which a plurality of blades are arranged side by side and the throat area is changed by rotating the plurality of blades around the span direction of the blades, the turn of the gas turbine By increasing the throat area during the down operation, the output supplied from the rotating shaft of the gas turbine can be reduced. In other words, turndown operation becomes easy.

Specifically, when a plurality of blades are rotated in a direction to reduce the rotating flow velocity component applied to the cooling air, the throat area increases. In this case, the amount of cooling air supplied to the moving blade system increases, and when the cooling air flows into the rotating moving blade system, the rotating flow velocity component that is insufficient from the rotor disk that connects the moving blade and the rotating shaft Is supplied to the cooling air. In other words, since a flow velocity component that rotates is supplied to the cooling air by using a part of the rotational driving force of the rotating shaft, the pumping loss increases and the output supplied from the rotating shaft to the outside decreases.
That is, the effect of the increase in the amount of cooling air and the increase in the pumping loss makes it possible to perform a turn-down operation with a lower load while maintaining a low emission.

  According to the gas turbine of the present invention, the adjustment unit for adjusting the flow rate of the cooling air flowing through the moving blade cooling system is provided during operation at a load lower than the full load, and the flow rate of the cooling air flowing through the moving blade cooling system is adjusted. By increasing the flow rate of the cooling air during operation at full load, it is possible to perform a low emission turn-down operation with a simple system while ensuring the reliability of the gas turbine. .

It is a distribution diagram explaining the composition of the gas turbine concerning a 1st embodiment of the present invention. It is a schematic diagram explaining the structure of the turbine part of FIG. 1, and a moving blade cooling system. FIG. 3 is a partially enlarged view illustrating a peripheral configuration of the TOBI nozzle of FIG. 2. FIG. 4 is a development view illustrating the configuration of the TOBI nozzle in FIG. 3. It is a schematic diagram explaining the structure of a ROBI nozzle. It is a schematic diagram explaining the structure of the moving blade cooling system of the 2nd Embodiment of this invention. FIG. 7 is a partially enlarged perspective view illustrating the configuration of the TOBI nozzle in FIG. 6. It is a systematic diagram explaining the structure of the conventional gas turbine.

[First Embodiment]
Hereinafter, a gas turbine according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is a system diagram illustrating the configuration of the gas turbine according to the present embodiment.
The gas turbine 1 according to the present embodiment performs full load operation and turndown operation, and supplies rotational driving force to an external device such as a generator.
As shown in FIG. 1, the gas turbine 1 is mainly provided with a compressor 2, a combustor (combustion unit) 3, a turbine unit 4, a rotating shaft 5, and a moving blade cooling system 6. Yes.

The compressor 2 sucks air used for combustion from the outside, compresses it, and supplies it to the combustor 3. Further, the compressor 2 supplies cooling air supplied to the moving blade cooling system 6. The compressor 2 is rotatably supported by the rotating shaft 5 and is rotationally driven by the rotating shaft 5.
In addition, as the compressor 2, the thing of a well-known structure can be used and it does not specifically limit.

The combustor 3 injects fuel into the compressed air supplied from the compressor 2 and burns it. The combustor 3 generates high-temperature combustion gas and supplies the combustion gas to the turbine unit 4. The combustor 3 is disposed between the compressor 2 and the turbine unit 4.
In addition, as a combustor 3, the thing of a well-known structure can be used and it does not specifically limit.

FIG. 2 is a schematic diagram illustrating the configuration of the turbine unit and the rotor blade cooling system in FIG. 1.
The turbine unit 4 extracts rotational driving force from the combustion gas supplied from the combustor 3. Further, the turbine unit 4 is rotatably supported by the rotating shaft 5 and transmits the extracted rotational driving force to the rotating shaft 5.
In the turbine unit 4, stages including a moving blade 41 and a stationary blade 42 are provided side by side along the axial direction of the rotating shaft 5.

The rotor blades 41 are arranged side by side on the outer peripheral surface of a disk-like rotor disk 43 provided on the rotary shaft 5 and are driven to rotate around the rotary shaft 5 by the combustion gas flowing therearound. It is. The stationary blade 42 extends from the inner peripheral surface of the casing constituting the turbine unit 4 toward the rotating shaft 5, and extracts the rotational driving force from the combustion gas flowing along with the moving blade 41.
In addition, as a structure of the turbine part 4, the thing of a well-known structure can be used and it does not specifically limit.

The rotating shaft 5 rotatably supports the compressor 2 and the turbine unit 4, and transmits the rotational driving force extracted by the turbine unit 4 to the compressor 2 and external devices.
In addition, as the rotating shaft 5, a well-known structure can be used and it is specifically limited.

The moving blade cooling system 6 supplies air compressed by the compressor 2 to the moving blade 41 as cooling air.
The moving blade cooling system 6 is provided with a cooling air flow path 61, a cooling air heat exchanger 62, a flow rate adjusting valve (adjusting unit) 63, and a TOBI nozzle (pre-rotating unit) 64.

The cooling air flow path 61 extracts a part of the air compressed by the compressor 2 as cooling air, and guides the extracted cooling air to the moving blade 41.
One end of the cooling air flow path 61 is connected to the turbine casing 31 that covers the combustor 3, and the other end is disposed at a position facing the rotor disk 43 of the rotor blade 41. Therefore, the compressed air before being compressed by the compressor 2 and flowing into the combustor 3 flows into one end of the cooling air channel 61. The cooling air flowing out from the other end of the cooling air flow path 61 is guided to the moving blade 41 through the cooling air flow path formed in the rotor disk 43.
A flow rate adjustment valve 63 is arranged in the middle of the cooling air flow path 61. Further, a TOBI nozzle 64 is disposed at the other end of the cooling air flow path 61.

  The cooling air heat exchanger 62 is a heat exchanger provided in the cooling air flow path 61, and releases the heat of the cooling air supplied to the moving blade 41 to the outside. In addition, as the cooling air heat exchanger 62, a well-known configuration can be used, and it is not particularly limited.

The flow rate adjusting valve 63 is a valve that adjusts the flow rate of the cooling air flowing through the cooling air flow path 61 and adjusts the flow rate of the cooling air based on the operating state of the gas turbine 1.
Specifically, the flow rate control valve 63 is provided in the middle of the piping from the extraction of the passenger compartment air to the reintroduction into the gas turbine 1, and cooling when the gas turbine 1 is in rated operation. Compared with the flow rate of the cooling air flowing through the air flow path 61, the flow rate of the cooling air flowing through the cooling air flow path 61 is increased when the turn-down operation is performed.

FIG. 3 is a partially enlarged view illustrating the peripheral configuration of the TOBI nozzle of FIG. FIG. 4 is a development view illustrating the configuration of the TOBI nozzle of FIG.
The TOBI nozzle 64 gives the cooling air flowing into the moving blade 41 and the rotor disk 43 from the cooling air flow path 61 with a flow velocity component that rotates in the rotating direction of the moving blade 41 and the like.
The TOBI nozzle 64 includes a platform 64A configured in a cylindrical shape, and a plurality of nozzle blades 64B arranged to extend radially outward from the outer peripheral surface of the platform 64A and arranged at equal intervals in the circumferential direction. Is provided. Furthermore, the TOBI nozzle 64 is composed of a plurality of segments SG divided at equal intervals in the circumferential direction. The segment SG is integrally formed.
The plurality of nozzle blades 64 </ b> B have a blade shape arranged so as to turn in the rotation direction of the moving blade 41 and the rotor disk 43 when the cooling air flows toward the rotor disk 43.

The narrowest channel cross-sectional area in the TOBI nozzle 64, that is, the throat area is larger than the area determined based on the flow rate of cooling air required for cooling the rotor blades 41 when the gas turbine 1 is rated. Is set.
More specifically, the throat area in a general gas turbine is the creep strength of the moving blade 41 during rated operation in a state where the operating conditions of the gas turbine are severe (high atmospheric temperature and high gas turbine inlet temperature), To flow the required airfoil system cooling air flow rate determined based on the total amount of blade cooling air required to ensure fatigue strength and prevent high-temperature oxidation and the amount of seal air required to purge the gaps between each part It is determined as a necessary and sufficient area. In the gas turbine 1 according to the present embodiment, the throat area is set larger than the necessary and sufficient area described above.

  For example, when the throat area in the TOBI nozzle 64 is set to be 20% larger than the above-mentioned necessary and sufficient throat area, the flow rate control valve 63 is throttled during rated operation, and the flow rate of the cooling air is set to the above-described required moving blade system cooling air flow rate. And On the other hand, during the turn-down operation, the flow rate control valve 63 is opened, and the flow rate of the cooling air flowing through the moving blade cooling system 6 can be increased by about 10% from the required moving blade system cooling air amount. This has the effect of reducing the load factor in turndown operation by about 1% abs. More specifically, the gas turbine 1 that has been operated at about 60% load can be operated at about 59% load under the same conditions.

Here, TOBI is an acronym for (Tangential On Board Injection). In the present embodiment, the description has been made by applying to the example in which the rotational speed component rotating to the cooling air flowing through the cooling air flow path 61 is given by the TOBI nozzle 64. However, as shown in FIG. 5, ROBI (Radial On Board Injection) is used. A flow velocity component rotating by the nozzle 64R may be given, and is not particularly limited.
FIG. 5 is a schematic diagram illustrating the configuration of the ROBI nozzle. In FIG. 5, a portion in which about 1/4 of the ROBI nozzle is enlarged is shown.

  Next, the operation of the gas turbine 1 having the above configuration will be described. First, the rated operation of the gas turbine 1 will be described with reference to FIG.

  When the compressor 2 is rotationally driven by the rotating shaft 5, external air is sucked into the compressor 2. The sucked air is compressed by the compressor 2 to become high-pressure air and is supplied to the combustor 3. In the combustor 3, fuel is injected into the compressed air, and an air-fuel mixture is combusted. High-temperature combustion gas generated by the combustion is supplied from the combustor 3 to the turbine unit 4.

  In the turbine unit 4, the moving blade 41 is rotationally driven by the combustion gas, and the rotational driving force is transmitted to the rotary shaft 5 through the rotor disk 43. The rotating shaft 5 transmits a part of the rotational driving force to the compressor 2 and is used for air compression in the compressor 2. The other rotational driving force is supplied to an external device such as a generator.

Here, the turndown operation of the gas turbine 1 which is a feature of the present embodiment will be described.
In the turndown operation in the gas turbine 1 of the present embodiment, the fuel-air ratio (fuel / air ratio) in the combustor 3 is kept high in order to prevent an increase in the amount of carbon monoxide contained in the exhaust gas. I'm leaning.

During the turn-down operation of the gas turbine 1, external air is sucked into the compressor 2 by the compressor 2 that is rotationally driven by the rotary shaft 5 as in the rated operation. The sucked air is compressed by the compressor 2 to become high-pressure air and is supplied to the combustor 3.
Here, when the entire amount of air sucked into the compressor 2 is supplied to the combustor 3, the fuel-air ratio in the combustor 3 decreases.

  Therefore, in order to supply only the amount of compressed air necessary for maintaining the fuel-air ratio in the combustor 3 to a predetermined value, the remaining compressed air flows into the rotor blade cooling system 6. In addition, the flow control valve 63 is opened. Since the subsequent flow and action of the compressed air supplied to the combustor 3 are the same as the flow and action during rated operation, description thereof will be omitted.

  When the flow control valve 63 is opened, the compressed air described above flows from the opening end of the cooling air passage 61 on the combustor 3 side as air for cooling the moving blades. The cooling air flowing through the cooling air channel 61 is cooled by the heat being radiated to the outside in the cooling air heat exchanger 62. The cooled cooling air passes through the flow rate adjustment valve 63 and flows into the TOBI nozzle 64.

  The TOBI nozzle 64 gives a flow velocity component that rotates in the rotation direction of the moving blade 41 and the rotor disk 43 to the cooling air. Specifically, the cooling air flows between the nozzle blades 64 </ b> B of the TOBI nozzle 64 along the rotation axis 5 toward the rotor disk 43 and becomes a swirl flow that swirls in the rotation direction of the rotor blades 41 and the rotor disk 43. .

  The cooling air ejected from the TOBI nozzle 64 is guided to the moving blade 41 through a cooling air flow path formed in the rotor disk 43. The cooling air guided to the moving blade 41 cools the moving blade 41, then flows out into the turbine section 4, that is, the flow path through which the combustion gas flows, and is discharged to the outside as exhaust gas.

According to the above configuration, when a load lower than the full load is supplied as an output from the rotating shaft 5, that is, when the gas turbine 1 is in a turn-down operation, the flow control valve 63 is opened. The flow rate of the cooling air flowing through the rotor blade cooling system 6 is larger than the flow rate when the gas turbine 1 is in rated operation (full load operation).
Therefore, cooling air can be supplied to the moving blades during the turndown operation without arranging a boost compressor in the moving blade cooling system 6.

  By increasing the flow rate of the cooling air that cools the moving blades 41 during the turn-down operation, the cooling air is supplied to the moving blades 41 that belong to a plurality of stages. Only the blade 41) is prevented from being excessively cooled, and the turndown operation can be performed without impairing the reliability of the moving blade 41. Furthermore, since the supply pressure drop of the cooling air to the stationary blade 42 is suppressed, the problem of BFM decrease in the stationary blade 42 does not occur, and the occurrence of burning of the moving blade 41 can be suppressed. That is, the turndown operation can be performed with a simple system while ensuring the reliability of the gas turbine.

By making the throat area in the TOBI nozzle 64 larger than the cross-sectional area of the flow path determined based on the flow rate of the cooling air flowing through the moving blade cooling system 6 when the gas turbine 1 is in rated operation (full load operation). In addition, the flow rate of the cooling air supplied to the moving blade 41 during the turndown operation can be reliably increased.
For example, when the throat area is equal to the cross-sectional area of the flow path determined based on the rated operation, even if an attempt is made to increase the flow rate of the cooling air supplied to the rotor blade cooling system 6, the portion of the throat area is It becomes a throttle and the flow rate of the cooling air supplied to the moving blade 41 cannot be increased effectively. In other words, the influence of the throat area on the flow rate of the cooling air supplied to the moving blade 41 is large. Therefore, by increasing the throat area, it is possible to effectively increase the flow rate of the cooling air supplied to the moving blade 41 during the turndown operation.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the gas turbine of the present embodiment is the same as that of the first embodiment, but the configuration for adjusting the flow rate of the cooling air flowing through the moving blade cooling system is different from that of the first embodiment. Therefore, in this embodiment, only the structure which adjusts the flow volume of cooling air is demonstrated using FIG. 6 and FIG. 7, and description of another component is abbreviate | omitted.
FIG. 6 is a schematic diagram illustrating the configuration of the moving blade cooling system of the present embodiment.
In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the description is abbreviate | omitted.

The moving blade cooling system 206 in the gas turbine 201 of the present embodiment supplies air compressed by the compressor 2 to the moving blade 41 as cooling air.
The moving blade cooling system 206 is provided with a cooling air flow path 61 and a TOBI nozzle (pre-rotation part) 264.

The TOBI nozzle 264 adjusts the flow rate of the cooling air that flows through the cooling air flow path 61, and adjusts the flow rate of the cooling air based on the operating state of the gas turbine 201.
Further, the TOBI nozzle 264 gives the cooling air flowing from the cooling air passage 61 to the moving blade 41 and the rotor disk 43 with a flow velocity component that rotates in the rotating direction of the moving blade 41 and the like.

FIG. 7 is a partially enlarged perspective view illustrating the configuration of the TOBI nozzle of FIG.
As shown in FIG. 7, the TOBI nozzle 264 includes a platform 264A formed in a cylindrical shape and a plurality of radially arranged outer circumferential surfaces of the platform 264A and at equal intervals in the circumferential direction. Nozzle blades 264B.

The platform 264A supports the nozzle blade 264B so as to be rotatable.
The nozzle blades 264 </ b> B are airfoil-shaped so as to turn in the rotation direction of the rotor blades 41 and the rotor disk 43 when the cooling air flows toward the rotor disk 43. Further, the nozzle blade 264B is provided with a rotation shaft 264C extending in the span direction (radial direction), and the nozzle blade 264B is rotatable around the rotation shaft 264C.

  By configuring in this way, the TOBI nozzle 264 can adjust the throat area. That is, the flow passage cross-sectional area through which the cooling air between the nozzle blades 264B flows can be adjusted by rotating the nozzle blades 264B around the rotation shaft 264C. For example, the throat area in the TOBI nozzle 264 can be increased by reducing the angle of the nozzle blade 264B with respect to the flow direction of the cooling air (the direction in which the rotating shaft 5 extends). Conversely, the throat area can be reduced by increasing the angle of the nozzle blade 264B.

  Specifically, when the gas turbine 201 is rated, the cooling air required to maintain the temperature of the moving blade 41 determined from the viewpoint of ensuring the minimum required strength of the moving blade 41. The angle of the nozzle blade 264B is adjusted so that the area determined based on the flow rate of the nozzle becomes the throat area.

  On the other hand, when the gas turbine 201 is in a turn-down operation, the flow rate of the cooling air flowing into the moving blade cooling system 206 necessary to keep the fuel-air ratio in the combustor 3 within a predetermined range. The angle of the nozzle blade 264B is adjusted so that the area determined based on the throat area becomes the throat area.

According to the above configuration, the flow rate of the cooling air supplied to the moving blade 41 via the moving blade cooling system 206 can be adjusted by changing the throat area in the TOBI nozzle 264.
Specifically, when the gas turbine 201 is in rated operation, the throat area can be changed in accordance with the flow rate of each cooling air in the case of turn-down operation. The throat area can be made larger than during rated operation. For this reason, it is possible to suppress the performance degradation of the gas turbine 201 during rated operation and to maintain low emission even during turndown operation.

  That is, the output supplied from the rotating shaft 5 of the gas turbine 201 can be reduced by increasing the throat area by rotating the nozzle blade 264B of the TOBI nozzle 264 during the turndown operation of the gas turbine. . In other words, turndown operation can be performed.

  Specifically, when a plurality of blades are rotated in a direction to reduce the rotating flow velocity component applied to the cooling air, the throat area increases. In this case, the amount of cooling air to the moving blade system increases, and when the cooling air flows into the rotating moving blade system, the rotating flow velocity component that is deficient from the rotor disk 43 that connects the moving blade and the rotating shaft 5 is reduced. Is supplied to the cooling air. In other words, since a flow velocity component that rotates is supplied to the cooling air using a part of the rotational driving force of the rotating shaft 5, the pumping loss increases, and the output supplied from the rotating shaft 5 to the outside decreases. That is, the effect of the increase in the amount of cooling air and the increase in the pumping loss makes it possible to perform a turn-down operation with a lower load while maintaining a low emission.

1,201 Gas turbine 2 Compressor 3 Combustor (combustion section)
4 Turbine part 5 Rotating shaft 6,206 Rotor cooling system 63 Flow rate regulating valve (regulating part)
64,264 TOBI nozzle (pre-rotation part)

Claims (3)

A compressor for compressing air used for combustion;
A combustion section that injects fuel into the compressed air and burns it to generate high-temperature combustion gas;
A turbine section that is rotationally driven by the combustion gas;
A blade cooling system for extracting a part of the compressed air as cooling air, and guiding the cooling air to the inside of the blades belonging to a plurality of stages constituting the turbine unit;
A gas turbine comprising:
The moving blade cooling system is provided with an adjusting unit for adjusting the flow rate of the cooling air flowing through the interior thereof,
A gas turbine characterized in that a flow rate of the cooling air flowing through the moving blade cooling system during operation at a load lower than a full load is larger than a flow rate of the cooling air during operation at the full load. The rotor blade cooling system is provided with a pre-swirl unit that gives a flow velocity component that rotates in the rotation direction of the rotor blade to the cooling air,
The throat area with the narrowest flow passage cross-sectional area of the cooling air in the pre-swirling portion is smaller than the flow passage cross-sectional area determined based on the flow rate of the cooling air flowing through the moving blade cooling system during operation at the full load. The gas turbine according to claim 1, wherein the gas turbine is large. The moving blade cooling system is provided with a pre-swirl unit that gives a swirl component that rotates in the rotational direction of the moving blade to the cooling air,
2. The gas turbine according to claim 1, wherein a throat area having the narrowest flow area of the cooling air in the pre-turning portion is controlled according to an operation state.

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