JP2010001740A - Cooling structure and refrigerant supply structure of gas turbine stator blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas turbine stator having excellent cooling performance and high reliability. <P>SOLUTION: The gas turbine stator is used for a high humidity gas turbine system in which water is sprayed into the compressed air compressed by a compressor 2 by a humidifier 5 and the high humidity air to which the water is sprayed by the humidifier 5 is supplied to a combustor 7. The gas turbine stator comprises, therein, a plurality of inner spaces 30a, 30b, 30c serving as cooling flow passages. A part of the compressed air compressed by the compressor 2 is supplied to at least one of the inner spaces 30a, 30b, 30c, and a part of the high humidity air to which water is sprayed by the humidifier 5 is supplied to the other cooling passages. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas turbine stationary blade and a cooling method thereof.

  Non-Patent Document 1 includes a hybrid cooling system in which a part of compressed air is extracted as a cooling medium for moving blades, and a part of the humidified air generated in the humidification tower is used as a cooling medium for stationary blades, and There has been disclosed a technique for effectively cooling a high-temperature part of a gas turbine with a small amount of cooling medium by a humidified air cooling system in which the cooling medium of all the moving blades and stationary blades is a high humidity air.

Proceedings of the Asian Congress on Gas Turbines ACGT2005-088

  In such a cooling structure, if all the cooling medium of the stationary blade is made into high-humidity air, the temperature difference between the combustion gas outside the blade and the cooling medium inside the blade becomes large in the vicinity of the leading edge, and a large amount of heat is generated. Stress is generated. In particular, an excessive thermal stress may occur in the first stage stationary blade exposed to high-temperature combustion gas.

  An object of the present invention is to provide a gas turbine stationary blade having excellent cooling performance and high reliability.

  Used in a high-humidity gas turbine system for supplying high-humidity air sprayed with a humidifier to the compressed air compressed by a compressor and supplying high-humidity air sprayed with water by the humidifier to a combustor. In a gas turbine stationary blade having a plurality of cooling channels, a part of the compressed air compressed by the compressor is supplied to at least one of the cooling channels, and the humidifier is connected to the other cooling channels. A part of the high-humidity air sprayed with water is supplied.

  According to the present invention, it is possible to provide a gas turbine stationary blade having excellent cooling performance and high reliability.

  2. Description of the Related Art Conventionally, a gas turbine system generally employed is configured to drive a turbine by obtaining a high-temperature and high-pressure working fluid by adding fuel to the working fluid compressed by a compressor and burning it. The rotational energy of the driven turbine is typically converted to electrical energy by a generator coupled to the turbine.

  In recent years, high humidity gas turbine (HAT) power plants have attracted attention. FIG. 4 shows the equipment configuration of the high-humidity gas turbine power plant. In a high-humidity gas turbine power plant, a gas turbine 1, a compressor 2, and a generator 3 are coupled to one shaft. Atmospheric air is supplied to the compressor 2 after moisture is added by the intake sprayer 14, and generates high-pressure compressed air having a temperature of about 300 ° C. and a pressure of about 2000 Pa in a state of rated load operation. The compressed air is cooled to about 100 ° C. in the air cooler 4 and then supplied to the humidifier (humidification tower) 5, and becomes humidified air at about 150 ° C. with moisture added and increased in humidity. The humidified air exiting the humidifier 5 is heated to around 550 ° C. in the regenerator 6 and burned together with fuel in the combustor 7 to become a high-temperature and high-pressure combustion gas having a temperature of 1300 ° C. or higher and a pressure of about 1900 Pa. . This combustion gas is supplied to the gas turbine 1 to drive the generator 3. The combustion gas that has been expanded and reduced in pressure in the gas turbine 1 is discharged as exhaust gas. However, since it is still sufficiently hot, the regenerator 6 exchanges heat with humidified air, and the water heater 8 further heats water and heat. Exchange is performed and heat energy is recovered. The exhaust gas exiting the feed water heater 8 is cooled in the exhaust gas reheater 9 and then supplied to the water recovery device 10. In the water recovery apparatus 10, the temperature of the exhaust gas is lowered by spraying low temperature water on the exhaust gas, and moisture in the exhaust gas is condensed and recovered. The exhaust gas containing a part of the moisture that has not been condensed is guided again to the exhaust gas reheater 9, heated and discharged from the chimney 11 to the atmosphere.

  One feature of the high-humidity gas turbine power plant is to increase the weight flow rate of the combustion gas by adding moisture in the humidifier 5 and the intake sprayer 14 to increase the humidity. Moreover, since the specific heat of water vapor is larger than that of air and more energy can be held inside, the output can be increased as compared with a normal gas turbine system. Furthermore, it is also a great feature that power generation efficiency is improved by recovering thermal energy in the regenerator 6 and the feed water heater 8 and recovering moisture in the water recovery device 10.

  In such a high humidity gas turbine system, the combustion gas contains a lot of moisture. Therefore, due to the difference in physical quantities such as viscosity coefficient and Prandtl number, the heat transfer coefficient is larger than that of air, and the specific heat is also larger. For this reason, since the thermal load in the gas turbine high temperature part such as turbine blades increases as compared with a normal gas turbine, it is necessary to enhance the cooling of the gas turbine high temperature part. In an ordinary gas turbine system, air cooling is performed by air extracted from a part of compressed air. However, since the high humidity gas turbine system requires a large amount of air, the temperature of the mainstream gas is lowered, and as a result, the thermal efficiency of the gas turbine is lowered. Therefore, in a high-humidity gas turbine, it is necessary to cool the high-temperature part of the gas turbine using a cooling medium having a higher cooling performance than air. A method of using humidified air (high humidity air) 19 extracted from the outlet of the humidifier 5 as the cooling medium is considered. Since high-humidity air contains moisture, the heat transfer rate is higher than that of air, and the specific heat is also large, so that the cooling performance is high. Therefore, it is possible to effectively cool the high temperature portion of the gas turbine with a small amount of cooling medium without increasing the number of devices.

  Since the air at the outlet of the humidification tower has a high humidity and a low temperature, the cooling potential is high, and it is desirable that all the cooling air is high-humidity air, but the reliability may be lowered.

  FIG. 5 shows a conventional cooling structure inside the stationary blade. The stationary blade 20 exposed to the high-temperature and high-pressure combustion gas 40 has a structure surrounded by a ventral side surface 21 and a back side surface 22 and has a plurality of internal cavities 30 inside. An insert 31 having a plurality of small holes on its surface is inserted into the internal cavity 30, and the cooling medium guided to the internal cavity 30 passes through the small holes at high speed and collides with the inner wall of the blade. Cool impingement. The ventral side surface 21 and the back side surface 22 are provided with a plurality of film holes 32 communicating with the combustion gas from the inner cavity, and the film after guiding the cooling medium after impingement cooling from the film holes to the vicinity of the blade outer surface. A cooling method is used.

  In such a cooling structure, if all of the cooling medium is high-humidity air, the temperature difference between the combustion gas 40 outside the blade and the cooling medium inside the blade becomes large in the vicinity of the blade leading edge 23, and excessive heat is generated. Stress is generated. In particular, an excessive thermal stress may occur in the first stage stationary blade exposed to high-temperature combustion gas.

  In order to deal with such problems, the gas turbine stationary blade of the present invention sprays water with a humidifier onto compressed air compressed with a compressor, and generates high-humidity air sprayed with water with a humidifier. In a gas turbine stationary blade having a plurality of cooling passages used in a high-humidity gas turbine system supplied to a combustor, a part of compressed air compressed by a compressor is contained in at least one of the cooling passages. A part of the high-humidity air supplied and sprayed with water by a humidifier is supplied to other cooling channels. By providing a part of the compressed air compressed by the compressor for cooling a portion where excessive thermal stress may occur, a gas turbine stationary blade having excellent cooling performance and high reliability is provided. be able to.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a cross-sectional view of a gas turbine stationary blade according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA of FIG. 1, that is, a vertical cross-sectional view of a gas turbine stationary blade that is an embodiment of the present invention.

  The stationary blade 20 is constituted by an abdominal side surface 21, a back side surface 22, an inner diameter side end wall 25, and an outer diameter side end wall 26. Divided into The inner space 30a is open on the inner diameter side end wall 25 side, and is supplied with the compressor bleed air 18. The inner spaces 30b and 30c are opened on the outer diameter side end wall 26 side, and the humidified air 19 is supplied thereto. Hollow inserts 31a, 31b, 31c having a plurality of small holes are installed in the internal spaces 30a, 30b, 30c, which are cooling channels. Film holes 32a, 32b, and 32c are provided in the stomach side surface 21 and the back side surface 22, and the internal spaces 30a, 30b, and 30c communicate with the combustion gas 40 through the film holes 32a, 32b, and 32c, respectively.

  The partition wall 27 is inclined to the front edge side on the back side, and the film hole 32b is disposed near the partition wall 27 on the back side. Here, the fact that the partition wall 27 is inclined to the front edge side on the back side means that the distance between the partition wall 27 located on the upstream side of the combustion gas flow path and the partition wall 28 on the downstream side of the combustion gas flow path is It means that the back side is far away. Alternatively, the blade 27 on the blade leading edge side is inclined to the blade trailing edge side and the blade back side to the blade leading edge side than the surface orthogonal to the blade belly side surface and the surface orthogonal to the blade back side surface. To do. By configuring in this way, the stationary blade can perform appropriate cooling corresponding to the front edge side becoming hotter than the rear edge side, and the ventral side becoming hotter than the back side. it can.

  The internal space 30 c communicates with the pin fin cooling passage 33 provided at the blade trailing edge 24 and communicates with the combustion gas 40. The stator blade of this embodiment is manufactured by precision casting of the entire blade including the leading edge cooling cavity and the downstream cooling channel, the film holes 32a, 32b, 32c are processed by electric discharge machining, and the insert 31a manufactured separately. , 31b, 31c. The hole diameter and number of impingement small holes in the insert, the hole diameter and number of film holes, etc. are designed according to the working gas conditions, blade cooling conditions and cooling targets, and the specifications do not represent the present invention.

  Next, the cooling method for the stationary blade of this embodiment will be described. Compressed bleed air 18 is supplied to the inner space 30a of the insert 31a, and is ejected from the small hole of the insert 31a to the blade cooling inner wall, and the impeller jet cools the blade from the inside. Further, the air is blown out from the film hole 32 a to the blade surface, and the blown air covers the blade surface against the combustion gas 40. On the wake side of the blade, high-humidity air 19 is supplied to the inner spaces 30b and 30c of the inserts 31b and 31c, and is ejected from the small holes of the inserts 31b and 31c to the blade cooling inner wall, and the blade is cooled from the inside by the impinging jet. . Further, the high-humidity air is blown out from the film holes 32 b and 32 c to the blade surface and covers the blade surface against the combustion gas 40. Further, the high-humidity air from the small hole of the insert 31c passes through the pin fin cooling passage 33 and cools the blade trailing edge 24 internally. Further, the partition wall 27 is inclined to the front edge side on the back side, and the film hole 32b is disposed closer to the partition wall 27 than the partition wall 28, and more preferably in the vicinity of the partition wall 27 on the back side. Enlargement is planned.

  FIG. 3 shows an example of the surrounding structure when the gas turbine stationary blade 20 of this embodiment is incorporated in a gas turbine. Inside the transition piece 50, the combustion gas 40 from the combustor flows into the outer surface of the stationary blade 20. On the inner diameter side of the stationary blade 20, an inner diameter side cavity 52 communicating with the compressor discharge space is formed by the inner diameter side end wall 25 and the support ring 51, and a part of the air is supplied to the stationary blade 20 as the compressor bleed air 18. Is done. On the other hand, an outer diameter side cavity 54 is formed on the outer diameter side of the stationary blade 20 by the outer diameter side end wall 26 and the turbine casing 53, and a supply pipe for the high-humidity air 19 is connected to a flange 55 provided in the turbine casing 53. By attaching, the humidified air 19 can be supplied to the stationary blade 20. As described above, the gas turbine structure necessary for implementing the present invention does not require a complicated structure and can be realized by a very simple configuration.

  The gas turbine stationary blade of the present embodiment includes a compressor that compresses air, a humidifier that sprays water on the air compressed by the compressor, moisture air and fuel sprayed with water by the humidifier, A turbine driven by combustion gas generated by the combustor, and a regenerator for exchanging heat between the combustion gas driving the turbine and the moisture air sprayed with water by the humidifier Used in a gas turbine system having a plurality of cavities for circulating a cooling medium therein, a plurality of film holes communicating with the main flow through which the working gas flows, and a plurality of small holes in the plurality of cavities. In a gas turbine stationary blade into which an insert having a hole is inserted, moisture air sprayed with water by a humidifier is supplied to a plurality of cavities, at least the most upstream cavity in the flow path of the combustion gas, In a cavity that does not supply moisture air, It is configured to provide a reduced air.

  The features of the stationary blade of this embodiment are as follows.

  By using the bleed air of the compressor as the cooling medium for the blade leading edge, the temperature difference between the metal inner surface and the outer surface at the blade leading edge 23 can be set small, so that excessive thermal stress can be suppressed. That is, compared with a stationary blade that cools the blade leading edge 23 with high-humidity air, the generated thermal stress can be kept low, and the strength reliability of the stationary blade is improved.

  By supplying high-humidity air as a cooling medium on the wake side of the blade, the internal cooling and film cooling effects are enhanced. Therefore, the amount of cooling air can be reduced as compared with the case where the stationary blade is cooled only by the bleed air of the compressor. As a result, the performance of the gas turbine can be improved.

  By dividing the internal cavity for supplying high-humidity air into a plurality of internal spaces, it is possible to perform cooling suitable for various places. On the back side of the blade, there is a part where the flow of combustion gas accelerates rapidly and the static pressure becomes low.However, because moisture air has a very high cooling effect, the film hole is also effectively applied to the back side of the blade. Can be arranged.

  As a synergistic effect of the characteristics described above, cooling air that can be reduced as a whole of the stationary blade of this embodiment will be described with reference to FIG. FIG. 6 shows the cooling air amount reduction effect by the gas turbine stationary blade of the present embodiment. As can be seen from FIG. 6, the amount of reduction in the cooling air flow rate by the blades of this embodiment corresponds to −22% from the cooling air flow rate by the compressor bleed air alone.

  Further, the stationary blade of this embodiment can be manufactured by a conventional turbine stationary blade manufacturing method, and an inexpensive cooling blade can be provided. That is, the stationary blade of this embodiment can be easily and accurately manufactured by precision casting including the formation of a cooling flow path, and there is no need to perform precision processing after precision casting, which is costly as in the prior art.

The cross-sectional view of the gas turbine stationary blade which is an Example of this invention. The longitudinal cross-sectional view of the gas turbine stationary blade which is an Example of this invention. The block diagram around the gas turbine stationary blade which is an Example of this invention. The block diagram of the high-humidity gas turbine power plant which is an Example of this invention. The cross-sectional view of the conventional gas turbine stationary blade. The cooling efficiency curve showing the effect of the gas turbine stationary blade which is the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 3 Generator 4 Air cooler 5 Humidifier 6 Regenerator 7 Combustor 8 Feed water heater 9 Exhaust gas reheater 10 Water recovery device 11 Chimney 12, 16 Pump 13 Desalination device 14 Intake sprayer 15 Cooling water 17 Cooler 18 Compressor bleed air 19 Humidified air 20 Stator blade 21 Ventral side surface 22 Back side surface 23 Blade leading edge 24 Blade trailing edge 25 Inner diameter side end wall 26 Outer diameter side end wall 27, 28 Bulkheads 30a, 30b, 30c Internal space 31a, 31b, 31c Insert 32a, 32b, 32c Film hole 33 Pin fin cooling passage 40 Combustion gas 50 Transition piece 51 Support ring 52 Inner diameter side cavity 53 Turbine casing 54 Outer diameter side cavity 55 Flange

Claims (8)

Used in a high-humidity gas turbine system for supplying high-humidity air sprayed with a humidifier to the compressed air compressed by a compressor and supplying high-humidity air sprayed with water by the humidifier to a combustor. In a gas turbine stationary blade having a plurality of cooling channels,
A part of the compressed air compressed by the compressor is supplied to at least one of the cooling channels, and a part of the high-humidity air sprayed with water by the humidifier is supplied to the other cooling channels. A gas turbine stationary blade configured to be supplied. A compressor that compresses air; a humidifier that sprays water onto the air compressed by the compressor; a combustor that burns moisture air and fuel sprayed with water by the humidifier; and A gas turbine system having a turbine driven by combustion gas generated by a combustor, and a regenerator for exchanging heat between the combustion gas driving the turbine and the moisture air sprayed with water by the humidifier A plurality of cavities for circulating a cooling medium therein, a plurality of film holes communicating with the main flow through which the working gas flows, and a plurality of small holes in the plurality of cavities. In the gas turbine stationary blade with the inserted insert,
Moisture air sprayed with water by the humidifier is supplied to at least the most upstream cavity in the combustion gas flow path of the plurality of cavities, and the compression is applied to a cavity not supplied with the moisture air. A gas turbine stationary blade configured to supply air compressed by a machine. The gas turbine stationary blade according to claim 2,
Three cavities partitioned into two partition walls, and the distance between the partition wall upstream of the combustion gas flow path and the partition wall downstream of the combustion gas flow path is on the back side rather than the ventral side A gas turbine stationary blade characterized in that is separated. The gas turbine stationary blade according to claim 2,
The three cavities are divided into two bulkheads, and the bulkhead on the blade leading edge side is on the blade trailing edge side and blade back side than the surface perpendicular to the blade belly side surface and the surface perpendicular to the blade back side surface. A gas turbine stationary blade characterized in that the side is inclined toward the blade leading edge. In the gas turbine stationary blade according to claim 3 or 4,
A gas turbine stationary blade, characterized in that a film hole provided on a blade back side surface of a cavity located in the center among the three cavities is provided near a partition wall on the upstream side of the flow path of the combustion gas. The gas turbine stationary blade according to claim 2,
It has an inner diameter side end wall having an opening and an outer diameter side end wall,
The compressed air is supplied to the inner space of the insert from the opening of the inner diameter side end wall, and the moisture air is supplied to the inner space of the insert from the opening of the outer diameter side end wall. A gas turbine stationary blade characterized by that. The gas turbine stationary blade according to claim 2,
The compressed air is supplied from an opening of the inner diameter side end wall through an inner diameter side cavity formed by an inner diameter side end wall and a support ring located on the inner diameter side of the inner diameter side end wall.
A gas turbine configured to supply the moisture air from an opening of the outer diameter side end wall through an outer diameter side cavity constituted by an outer diameter side end wall and a turbine casing. Static wing. Used in a high-humidity gas turbine system for supplying high-humidity air sprayed with a humidifier to the compressed air compressed by the compressor and supplying the humidified air sprayed with water by the humidifier to the combustor. In the method for cooling a gas turbine stationary blade having a plurality of cooling channels,
A part of the compressed air compressed by the compressor is supplied to at least one of the cooling channels, and a part of the high-humidity air sprayed with water by the humidifier is supplied to the other cooling channels. A cooling method for a gas turbine stationary blade, characterized by comprising:

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