JPS61169601A - Gas turbine blade - Google Patents

Abstract

PURPOSE:To equally cool and entire blade by installing a supply passage and a exhaust passage inside the blade to allow a gradual increase of cooling fluid from the root section of the blade toward the central section, and a gradual decrease of cooling fluid from the central section toward the tip section. CONSTITUTION:The first flow passage 7 is formed inside a turbine nozzle 5 along the direction of a blade to communicate with a supply source of cooling fluid. The second flow passage 10 is formed, while being communicated with the above passage 7 through a plurality of small ports 8, and with its one end opened at the trailing edge of the nozzle 5 through a slit 9, and a plurality of pin fins 11 are installed inside the passage 10. By this constitution, cooling fluid introduced into the passage 7 flows out from the small ports 8 to cool the frontal section (A) of the nozzle 5, and especially efficiently to cool the central section. The cooling fluid introduced into the passage 10 cools the rear section (B) while passing through spaces among fins 11, and especially efficiently to cool the central section. Thus, the entire nozzle 5 is evenly cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas turbine, and more particularly to a gas turbine having an improved cooling structure.

[Technical Background of the Invention] Gas turbines have advantages over other prime movers in that they are small and lightweight and can provide high output, and are therefore widely used in power generation plants for aircraft and the like.

In a gas turbine, normally a compressor 1 is installed as shown in Fig. 3.
The high-pressure air compressed by the gas turbine is guided to the combustor 2, where fuel is injected from the fuel nozzle 3 and combusted, and the high-temperature, high-pressure gas generated by this combustion is guided to the gas turbine 4 and rotated to generate rotational power. It is configured as follows. In order to improve the performance of such a gas turbine, it is most effective to increase the combustion gas temperature at the inlet of the turbine 4, and in recent years there has been a tendency to increase the combustion gas temperature of gas turbines. However, as the concentration of combustion gas increases, the strength and lifespan of component parts decreases, so parts that are exposed to high-temperature combustion gas, especially turbine blades such as nozzles 5 and blades 6 that are used under high stress, require cooling. It becomes essential.

[Problems with the Background Art] By the way, when combustion is performed in a gas turbine as shown in FIG. The combustion gas near the center of the shaft has the highest temperature. When such combustion gas is guided to the turbine 4,
At the inlet of the nozzle 5 and blade 6, as shown in FIG.
This results in non-uniform temperature distribution in the radial direction.

Therefore, the area near the center of the turbine blade is exposed to the highest temperature combustion gas, but with conventional turbine blades, cooling is performed uniformly along the height of the blade, so cooling occurs near the center of the stomach. There is a high possibility that the effect will be insufficient and the turbine blades will be damaged. On the other hand, in order to sufficiently enhance the cooling effect near the central part of the stomach, a large amount of cooling fluid is required, which has the disadvantage of impairing the performance of the gas turbine.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to successfully cool both parts with a minimum amount of cooling fluid, thereby improving performance and reliability. Our objective is to provide gas turbine blades.

[Summary of the Invention] The gas turbine blade according to the present invention has a cooling system in which the amount of cooling fluid gradually increases from the root to the center of the blade, and the amount of cooling fluid gradually decreases from the center to the tip. It is characterized in that a fluid supply channel and a fluid discharge channel are provided inside the blade.

[Effect of the invention 1] With the above configuration, the cooling fluid can be supplied in a concentrated manner near the center of the turbine blade, which is exposed to the highest temperature combustion gas, so that this part can be effectively cooled. I can do it. The root part is exposed to relatively low temperature combustion gas,
Or because the cooling fluid supplied to the tip is small,
The entire turbine blade can be cooled to a uniform temperature.

As a result, thermal stress caused by temperature differences can be alleviated, extending the life of the turbine blade.

By properly distributing the cooling fluid along the height of the turbine blades, the overall amount of cooling fluid can be significantly reduced compared to conventional methods, resulting in improved gas turbine performance. can be achieved.

Furthermore, since the amount of cooling fluid discharged into the mainstream is greatest in the central region of the stomach, this cooling fluid mixes with the mainstream,
The temperature distribution in the radial direction can be made uniform on the downstream side of the turbine blade.

[Embodiment of the Invention] An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example in which the present invention is applied to a turbine nozzle. That is, along the opening direction inside the nozzle 5, there is a first channel 7 that communicates with a cooling fluid supply source, and a plurality of small holes 8 that communicate with the channel 7, and one end of which is connected to the nozzle through a slit 9. 5
A second flow path 10 that opens at the rear edge is provided, and a plurality of bottle fins 11 are further disposed inside the second flow path 10. A large number of the small holes 8 are provided near the center of the nozzle 5 and arranged so that the number gradually decreases from the center toward the root or tip. Further, the width of the slit 9 is wide near the center of the nozzle 5 and gradually narrows as it moves away from the center.

The present invention has the above configuration, and the cooling fluid guided to the first flow path 7 is ejected from the small hole 8 as shown in FIG. 2 to cool the front portion A of the nozzle 5. (Impingement cooling), since a large number of small holes 8 are provided near the center of the nozzle 5, which is exposed to the highest temperature gas, the amount of cooling fluid supplied is also the largest, effectively cooling the center. be able to. On the other hand, at the root or tip, the number of small holes 8 is small and the amount of cooling fluid is also reduced, resulting in various excellent effects as described above.

On the other hand, the cooling fluid guided to the second flow path 10 cools the rear part B of the nozzle 5 while passing between the plurality of bin fins 11 (bin fin cooling). Most effectively cools the area around the area. After this, the cooling fluid is finally discharged into the mainstream through the slit 9,
Since the discharge amount is approximately proportional to the slit width, it is highest near the center of the nozzle 5 and gradually decreases as it moves away from the center. Since most of the cooling body is discharged near the center where the mainstream temperature is highest, by mixing with the mainstream, the temperature distribution is made uniform in the radial direction on the downstream side of the nozzle 5.

Although FIG. 1 shows an example in which the present invention is applied to the nozzle 5, it is not necessarily necessary to apply the present invention to the nozzle, and even when applied to the blade 6, similar excellent effects can be obtained.

Also, although Figure 1 shows an example in which the cooling fluid is discharged from the trailing edge of the blade into the mainstream, it does not necessarily have to be from the trailing edge, but can also be applied to the case where it is discharged from the surface of the turbine blade (film cooling). I don't mind.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a gas turbine blade according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ll-ff in FIG. 1, and FIG. 3 is a sectional view of a conventional gas turbine blade. FIG. 4 is a partially cutaway side view and is an explanatory diagram showing the radial temperature distribution of combustion gas at the turbine inlet. DESCRIPTION OF SYMBOLS 1... Compressor, 2... Combustor, 3... Fuel nozzle, 4... Turbine, 5... Nozzle, 6... Vane,
7...First flow path, 8...Small hole, 9...Slit, 10...Second flow path, 11...Pinfin agent, patent attorney Kensuke Norichika (and one other person) ) Figure 1 Figure 3

Claims (1)

[Claims] Supply of cooling fluid inside a turbine blade such that the amount of cooling fluid gradually increases from the root to the center of the blade, and conversely the amount of cooling fluid gradually decreases from the center to the tip. A gas turbine blade characterized by having a flow path and a discharge flow path.