JPS60212630A - Gas turbine - Google Patents

Abstract

PURPOSE:To improve an output, by a method wherein, in a device which guides a part of air, compressed by a compressor, as as cooling air to a turbine impeller, the device is constituted such that water is sprayed directly in cooling air in an air cooling cylinder. CONSTITUTION:Air, compressed by a compressor 2, is guided to a combustor 3 by a gas turbine 1, and high temperature and high pressure gas, generated by the combustor 3, is fes to a turbine 4. In which case, an intermediate support plate 13 for a combustor is mounted in an annular manner to a combustor chamber 10, the interior of a combustor chamber 10 is partitioned into the combustor body side and the combustor tail cylinder 14 side, and a cooling air chamber 30 is formed on the combustor tail cylinder 14 side. An air cooling cylinder 5, extending through the intermediate support plate 13 and being open to the combustor body side and the combustor tail cylinder 14 side in the combustor chamber 10, is installed in the combustor chamber 10. A water spray device 6, connected to a water feed source 9 through an on-off valve 8, is positioned in the cooling cylinder 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a system for effectively cooling a part of air compressed by a gas turbine compressor with spray water sprayed from a spray device and then using it as cooling air. This relates to gas turbines.

[Prior art]

In recent years, in order to improve the performance of gas turbines and (1) increase output, gas temperatures used in gas turbines have tended to become higher and higher.

However, in order to maintain the strength of the turbine blades of a gas turbine, it is necessary to maintain the temperature below a certain level, and a method of cooling the turbine blades is adopted as a means for this purpose.

Turbine blades are cooled by directing a portion of the air compressed by a compressor into the turbine blade as cooling air, using film cooling, impingement cooling, convection cooling, etc.
In order to keep the turbine blades below a certain temperature, the amount of cooling air used needs to increase as the temperature of the gas used increases.

However, an increase in cooling air usage leads to a decrease in gas turbine cycle efficiency due to an increase in the power required for cooling air compression and a decrease in average gas temperature due to the increase in the amount of cooling air mixed with the mainstream gas. There's a problem.

In addition, since the cooling air uses air compressed by a compressor driven by the gas turbine, (2) Although its temperature is lower than that of combustion gas, as the output of gas turbines increases, the compressor The compression ratio of is increasing, and its temperature is also increasing.

Therefore, when cooling the turbine blades, the temperature difference between the cooling air and the mainstream gas becomes correspondingly smaller, and the cooling effect becomes worse.

Furthermore, while the cooling air is being led to the turbine blades,
The temperature rises due to exposure to the surrounding high-temperature atmosphere, and this tendency increases as the combustion gas temperature increases.

Therefore, if the air compressed by the compressor is used as cooling air, and the temperature of the turbine blade is kept below a certain level necessary to maintain its strength, the amount of cooling air can be increased. , it is impossible to raise the mainstream gas temperature above a certain value.

As a countermeasure to this problem, there is a system in which the cooling air is once guided outside the gas turbine and cooled using an air fin cooler or the like, but in this case, although the temperature of the cooling air is lowered, the structure is complicated. (3) There is a problem in that the pressure drop increases and the difference between the pressure of the cooling air and the gas pressure at the turbine inlet becomes small, making it impossible to film-cool the leading edge of the first-stage stationary blade.

Furthermore, if the temperature of the gas used in the gas turbine increases, the temperature of the combustor also increases, which poses a problem in the heat resistance of the members that make up the combustor.

That is, increasing the temperature of the gas used in the gas turbine means increasing the combustion temperature, and each part of the combustor is exposed to higher temperature combustion gas.

Here, a large amount of dilution air flows into the inner cylinder of the combustor from the surroundings, and this dilution air blocks the heat of the combustion gas and protects the inner cylinder from exceeding an allowable temperature.

However, the transition piece of the combustor has a double structure consisting of an inner and outer plate with a spacing of several millimeters, for example, and a small hole is made in the outer plate, through which air compressed by a compressor is guided to cool the inner plate. In addition, small holes are made in the inner plate, and air is blown into the passage through these holes to form a film of air and block the heat of the combustion gas. The temperature of the air itself becomes high, and a sufficient cooling effect cannot be obtained. If the amount of air for cooling is increased as a countermeasure, the power required for the compressor will increase and the average mainstream gas temperature will also decrease, resulting in a problem that the cycle efficiency of the gas turbine will decrease.

In particular, the temperature of the combustor transition piece is high because it comes into direct contact with the combustion gas, and it is made up of relatively thin plates, so even a small drop of water will rapidly cool this part, causing cracks to occur due to thermal stress.

Furthermore, if other parts are directly hit by water droplets, those parts will be rapidly cooled and cause cracks to occur.

[Purpose of the invention]

Therefore, the present invention solves the above conventional problems and improves the cycle efficiency of the gas turbine by effectively cooling the cooling air of the gas turbine with a water spray device provided in the gas turbine. It is intended for this purpose.

(5) [Structure of the Invention] That is, the present invention provides a gas turbine that cools the turbine blades by introducing a part of the air compressed by the compressor of the gas turbine to the turbine blades as cooling air. The combustor chamber is divided into the combustor main body side and the combustor transition pipe (separately), an air cooling pipe is provided that penetrates the partition, and a spray device capable of spraying water is provided inside the pipe.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a gas cooler according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic system diagram of a gas turbine according to an embodiment of the present invention, with the upper half showing the AA cross section in FIG. 3 described later, and the lower half showing the BB cross section in FIG. 3 described later. In the figure, this gas turbine 1 is composed of a compressor 2, a combustor 3, and a turbine 4.

Next, FIGS. 2A and 2B are side sectional views of the main parts of the gas turbine 1, and FIG. 2A is the upper half of the first (6) diagram, that is, the AA cross section of FIG. 2B corresponds to the lower half of FIG. 1, that is, the BB cross section of FIG. 3, and cooling air flows as shown by arrow C in the figure.

Here, in the combustor chamber 10, as shown in the longitudinal cross-sectional views of main parts in FIG. 2A and FIG. Combustor main body 3 having an inner cylinder 11 and a combustor flow guide 12
1 side and the combustor transition piece 14 side, and a cooling air chamber 30 is formed in the combustor transition piece 14+l+.

As shown in FIG. 2B, the combustor chamber 10 is provided with an air cooling M5 that penetrates the combustor intermediate support plate 13 and opens on the combustor main body 31 side and the combustor transition piece 14 side. As shown in FIG. 1, a spray device 6 for spraying water is provided inside this cylinder, and the spray device 6 is connected to a water supply source 9 outside the gas turbine 1 through a pipe 7. A valve 8 is provided to stop the spraying.

Here, in order to completely evaporate the water (7) while it flows inside the air cooling cylinder 5, the length of the air cooling cylinder 5 is made as long as possible, and a 1! It is better to install a fog device 6.

In addition, as shown in FIG. 2A, the combustor tail i'1i14 is
It has a double structure with an inner plate 15 and an outer plate 16, with a large number of small holes 18 and 19 bored in both, and a spacer 17 provided in the middle to maintain the spacing.

Further, a space 27 sealed by a compressor high pressure side seal ring 23 and a turbine inlet side seal ring 24 is provided between the connecting member 21 and the torque tube 22, and a space 27 is provided between the connecting member 21 and the torque tube 22, and a space 27 is formed between the cooling air chamber 30 and the cooling air bleed holes 25 and 26. It communicates with a space 28 within the torque tube 22.

Therefore, the air compressed by the compressor 2 enters the combustor chamber 10 as shown in FIG. 2A, and most of it is supplied to the combustor main body 31, but a part of it is shown in FIG. 2B. The air enters the air cooling cylinder 5, where it is cooled by atomized water sprayed from the spray device 6.

(8) Air cooled by the atomized water sprayed from the spray device 6 in the air cooling cylinder 5 enters the cooling air chamber 30, and a part of the air flows through the cooling air holes 34, 34 of the turbine blade ring 33. and is supplied to the turbine stator blades 35°37. Also, some
As shown in FIG. 2A, the small hole 19 of the outer plate 16 of the combustor transition piece 14 enters the space 20, blows out from the small hole 18 of the inner plate 15 to the mainstream, and a part of the cooling air of the connecting member 21 enters the space 20. The cooling air enters the space 27 from the air bleed hole 25 and enters the space 28 inside the torque tube 22 from the cooling air bleed hole 26 of the torque tube 22.
the turbine disk 4 through the ventilation hole 43 of the turbine disk 40 and the ventilation hole 44 of the spacer disk 41.
0.42 and enters the space 45 between the cooling air holes 46. and 47.48 to the turbine rotor blades 36.38.

〔Effect of the invention〕

As described above, the present invention directs a part of the air compressed by the compressor of a gas turbine to the turbine blades as cooling air,
Cooling the Turbine Blades (9) The combustor chamber of the gas turbine is partitioned into the combustor main body side and the combustor tail Tf4011+, and an air cooling cylinder is provided that penetrates the partition, and water is poured into the cylinder. Since a spraying device capable of spraying is provided and water is sprayed from this spraying device, many effects such as those described below can be obtained.

+a1 According to the present invention, since water is directly sprayed into the cooling air, the air can absorb approximately 600 kcal/kg of heat as latent heat of vaporization for water to evaporate, so it can be sufficiently effectively cooled. .

If the cooling air can be cooled and its temperature lowered, the temperature difference between it and the turbine blades will increase, greatly improving the cooling effect and increasing gas turbine cycle efficiency.

('b) Also, according to the present invention, since water is sprayed into the cooling air, the specific heat of the cooling air increases accordingly, which reduces the amount of cooling air compressed by the compressor. Increased efficiency.

(cl) Furthermore, according to the present invention, the combustor chamber is partitioned, and the air sprayed with water and cooled does not flow into the combustor main body (10), thereby improving the cycle efficiency of the gas turbine.

+d) Furthermore, according to the present invention, since water is sprayed in the cooling passage inside the gas turbine, the pressure drop does not increase as in the case where the water is once guided outside the gas turbine and cooled by a cooling device such as an air fin cooler. Therefore, film cooling of the first stage stator blades of the turbine, which was impossible with this method, can be performed without any problem.

Further, according to the present invention, since water is sprayed into the air cooling cylinder, the sprayed water evaporates while flowing inside the cylinder, and is completely evaporated when it reaches the cooling air chamber. Therefore, since water does not come into direct contact with the turbine components that have become hot, the turbine components do not develop cracks.

(fl) Furthermore, according to the present invention, the combustor chamber is partitioned into the combustor main body side and the combustor transition piece side, and the cooling air chamber is configured to wrap around the transition piece, so that a spray device is used to cool the transition piece. Air cooled by sprayed water can be used.

Therefore, since the transition piece can be effectively cooled, the temperature of the gas used by the gas turbine can be increased.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram of a gas turbine according to an embodiment of the present invention, Figures 2A and 2B are enlarged side sectional views of the main parts of the gas turbine in Figure 1, and Figure 3 is a combustor intermediate support. It is a front view of the main part of a board. 1... Gas turbine, 5... Air cooling cylinder, 6...
spray device, 10... combustor chamber, 14... combustor transition piece, 31... combustor main body.

Claims (1)

[Claims] In a gas turbine that cools the turbine blades by introducing a part of the air compressed by the compressor of the gas turbine as cooling air to the turbine blades, the combustor chamber of the gas turbine is divided into two parts: the combustor main body side and the combustor transition piece side. What is claimed is: 1. A gas turbine characterized in that a gas turbine is partitioned into a gas turbine, an air cooling cylinder is provided passing through the partition, and a spray device capable of spraying water is provided in the cylinder.