JPH03194101A - Gas turbine cooling moving blade - Google Patents

Abstract

PURPOSE:To enable uniform cooling of a chip shroud in a gas turbine cooling moving blade in which a cooling passage penetrating a shank and a blade effective part of the moving blade is formed by forming a cooling passage communicating to the above cooling passage in the chip shroud attached at the blade tip of the blade effective part. CONSTITUTION:In a gas turbine cooling moving blade, a shank 2 and a blade effective part 3 are arranged in series above a stud part 1 in the form of a tree, and a cooling passage is provided inside so that it penetrates the stud part 1, the shank 2 and the blade effective part 3. At a blade tip 3b of the blade effective part 3, a chip shroud 4 whose plane form is almost the letter of Z is formed. In this case, a cooling passage 6 is formed in the chip shroud 4. This cooling passage 6 is formed by an outer circumferential wall and a plurality of partition walls in a chip shroud bottom part 4A formed integrally with the blade effective part 3, and is made to communicate to a cooling passage 3a in the blade effective part 3 by a communication hole 7. Also, a discharge hole 8 of a small diameter is provided on the upper surface of a chip shroud upper lid 4B.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a gas turbine cooling rotor blade, and in particular, a cooling passage is formed in a tip shroud so that the tip shroud can be cooled uniformly. The present invention relates to a gas turbine cooling rotor blade.

(Prior Art) Generally, in this type of gas turbine, a gas passage is formed in a casing for flowing high-temperature combustion gas, which is a working fluid. Stator blades and rotor blades are arranged alternately within this gas passage.The stator blades are fixed to the casing and are held so as not to move within the gas passage, while the roots of the rotor blades are radially connected to the turbine rotor. It is installed so that it can rotate integrally with the turbine rotor. Further, a shroud segment is fixed to the inner surface of the casing facing the blade tip of the rotor blade.

By the way, in order to increase the output of the gas turbine or improve the output efficiency, it is sufficient to increase the gas turbine inlet temperature, but in this case, the amount of heat input into the gas passage also increases, causing the gas passage to become The temperature of each member becomes considerably high. Therefore, there is a risk that material strength may decrease or material corrosion may occur due to high-temperature oxidation.

Therefore, in order to prevent this, various methods have been taken to cool the above-mentioned constituent members. For example, air, steam, water, etc. are used as the cooling medium, but a cooling method that uses low-temperature bleed air extracted from a compressor of a gas turbine is common.

On the other hand, in this type of gas turbine, a tip shroud is formed at the tip of the rotor blade in order to improve the aerodynamic performance of the rotor blade and prevent resonance phenomena. However, although this chip shroud can achieve the above purpose, it is subjected to large tensile stress due to centrifugal force during rotation. This type of chip shroud does not have a cooling means, or has a cooling means as a cooling means.
There is also one in which the discharge holes are arranged on the surface of the tip shroud as shown in FIG. 14 and FIG. That is, in FIG. 13, the discharge hole 31.31 is provided so as to penetrate the tip shroud 32, and the discharge hole 31.31 is provided so as to pass through the tip shroud 32.
A cooling passage (
A portion of the cooling air flowing through the tip shroud (not shown) can be released to provide film cooling of the chip shroud.

(Problems to be Solved by the Invention) However, in the film cooling method described above, the cooling air flow is formed only in a narrow range, and the end portion 36.
6..., a sufficient cooling effect cannot be obtained. For this reason,
The metal temperature becomes non-uniform in various parts of the surface of the chip shroud, causing a problem that sufficient strength cannot be obtained in the chip shroud. In order to avoid this problem, rotor blades of a type without a tip shroud are also used in high-pressure stage rotor blades, as shown in FIGS. 15 and 16.

However, in this rotor blade, the clearance formed between the blade tip and the shroud segment includes the ventral side 35 of the blade effective part.
A tip leak as shown by the arrow in the figure occurs from a to the dorsal side 35b, and the loss at the tip of the rotor blade increases.

For this reason, there is a problem in that the gas turbine performance is significantly reduced compared to rotor blades having a tip shroud.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cooling rotor blade for a gas turbine that solves the problems of the conventional technology described above, has a uniform cooling effect even in the tip shroud, and can improve the performance of the gas turbine in the high pressure stage. Our goal is to provide the following.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention connects a shank and an effective blade part to an embedded part embedded in a turbine disk, and also provides a blade tip of the effective blade part. In a gas turbine cooling rotor blade, a tip shroud is attached to the blade, and a cooling passage is formed so as to pass through the inside of the shank and the inside of the blade effective part,
A hollow part is formed inside the tip shroud, a partition wall is arranged in the hollow part to form a cooling passage, and this cooling passage and a cooling passage in the effective blade part are communicated through a connecting hole, and the surface of the tip shroud is A discharge hole is provided in the
This is characterized in that cooling air is supplied into the tip shroud from within the blade effective section.

(Function) According to the present invention, a hollow part is formed inside the tip shroud, a partition is arranged in this hollow part to form a cooling passage, and this cooling passage and the cooling passage in the above-mentioned blade effective part are connected by a connecting hole. In addition to providing communication, a discharge hole is provided on the surface of the tip shroud to supply cooling air from within the effective part of the blade to the tip shroud, so that the tip shroud can be uniformly cooled by the cooling air flowing inside the tip shroud. can.

(Example) An example of a gas turbine cooling rotor blade according to the present invention will be described below with reference to FIGS. 1 to 6. In this embodiment, a cooling rotor blade employing a return flow type convection cooling method with high cooling efficiency will be explained as an example, but the operation and effect are similar for other cooling methods.

Figures 1 and 2 show the entire gas turbine cooling rotor blade, and number 1 in the figures indicates the implanted part. Similarly, it can be embedded in a turbine disc (not shown). A shank 2 and an effective blade portion 3 are connected above the implanted portion 1. The shank 2 has a substantially quadrangular trapezoidal shape, and platforms 2a, 2a, . . . are formed to enhance the sealing effect against gas. In addition, the airfoil of the blade effective part 3 is formed so that the root 3a and the blade tip 3b are twisted, and the airfoil (not shown) is formed inside so as to penetrate through the implanted part 1, the shank 2, and the blade effective part 3. A cooling passage is formed. The cooling air in this cooling passage convectively cools the blade effective section 3, a part of which cools the blade leading edge 3C as a film, and the rest is released into the combustion gas from the blow-off holes at the blade trailing edge.

Further, as shown in FIGS. 3 and 4, a tip shroud 4 is formed at the blade tip 3b of the blade effective section 3. This chip shroud 4 has a substantially Z-shaped planar shape, and includes a lower chip shroud 4A formed integrally with the effective blade section 3 and a chip shroud upper lid 4B fixed to the lower chip shroud 4A in a stacked manner. It consists of The tip shroud lower part 4A is formed integrally with the blade effective part 3 during precision casting, while the tip shroud upper cover 4B is manufactured by precision casting or machining, and its upper surface has two rows of fins 5 for wing tip sealing. .5
is installed. In addition, the chip shroud upper cover 4
B and the chip shroud lower part 4A are machined on their mating surfaces and are joined by a diffusion bonding method.

On the other hand, FIGS. 5 and 6 show cooling passages 6 formed within the chip shroud 4. As shown in FIG. The cooling passage 6 is integrally formed inside the chip shroud lower portion 4A, and consists of an outer peripheral wall and a plurality of partition walls. The cooling passage 6 is formed during precision casting of the blade body, or is formed by machining in the tip shroud lower part 4A, which is previously cast into a flat shape. Further, two connecting holes 7.7 are formed in the bottom surface of the cooling passage 6 to communicate with the cooling passage 3d in the blade effective section 3. This connecting hole 7 is usually formed using a ceramic core or the like at the same time as precision casting of the blade body.

On the other hand, three small-diameter discharge holes 8 are bored in the upper surface of the tip shroud upper cover 4B. This discharge hole 8 plays the role of discharging the cooling air that has flowed into the cooling passage 6 into the combustion gas, and is formed at the same time as precision casting of the M4B on the tip shroud, or is bored later by machining. It looks like this.

According to the configuration described above, the flow of cooling air in the cooling passage 6 of the chip shroud 4 is as shown in FIGS. 5 and 6. That is, a portion of the cooling air flowing through the cooling passage 3d in the blade effective portion 3 flows into the cooling passage 6 of the tip shroud 4 through the connection hole 7, convects inside, and is discharged from the discharge hole 8. This allows the chip shroud 4
The interior can be cooled evenly.

7 and 8 show a cooling passage 6 provided with pin fins 9, 9, etc. as heat transfer accelerators as another embodiment. They are set up at regular intervals. Moreover, FIGS. 9 and 10 show a cooling passage 6 in which turbulence promoters 10, 10, . . . are disposed as heat transfer promoters.

This turbulence promoter 10 is a rod-shaped convex portion extending in a direction perpendicular to the flow direction of cooling air,
They are provided protrudingly on both the upper and lower surfaces of the cooling passage 6 at regular intervals. By using the heat transfer promoter in this way, the surface area within the cooling passage 6 can be increased, and the cooling efficiency can be further improved.

FIGS. 11 and 12 show another embodiment of a cooling passage 6 in which discharge holes 8 are formed in the lower surface of the lower tip shroud 4A. By providing the discharge holes 8 in this manner, cooling air can be discharged into the gas passage, and the effective portion of the blade can be film-cooled. At this time, the discharge hole 8 is formed obliquely toward the rear so that the discharged cooling air does not disturb the flow of the combustion gas.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a cooling passage is formed inside the chip shroud, and cooling air is supplied into the chip shroud by this cooling passage, so that the chip shroud is uniformly cooled. As a result, it becomes possible to provide a tip shroud even on the rotor blades of the high pressure stage, and effects such as improving the performance of the gas turbine can be expected.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an overall outline of an embodiment of a gas turbine cooling rotor blade according to the present invention, FIG. 2 is a front view of the same, and FIG. FIG. 4 is an enlarged plan view of a portion of the blade, FIG. 4 is a front view thereof, and FIGS. 7
8 and 8 are cross-sectional views showing a chip shroud cooling passage provided with bin fins as another embodiment, and FIGS. 9 and 10 show a chip shroud cooling passage provided with a turbulence promoter as another embodiment. cross-sectional view, 1st
Figure 1 is a plan view showing a chip shroud cooling passage in which discharge holes are provided on the lower surface of the chip shroud as another embodiment;
FIG. 12 is a front view of the same, FIG. 13 is a plan view schematically showing an example of the rotor blade having a conventional tip shroud, and FIG.
4 is a front view of the same, FIG. 15 is a plan view schematically showing an example of a rotor blade without a conventional tip shroud, and FIG.
The figure is a front view of the same. 3... Wing effective part, 4... Chip shroud, 6...
- Cooling passage, 7... connection hole, 8... discharge hole.

Claims (1)

[Claims] The shank and the blade effective part are connected to an embedded part embedded in the turbine disc, and a tip shroud is attached to the blade tip of the blade effective part so as to pass through the inside of the shank and the blade effective part. In a gas turbine cooled rotor blade having a cooling passage formed therein, a hollow part is formed inside the tip shroud, a partition is arranged in the hollow part to form a cooling passage, and this cooling passage and a cooling passage in the effective part of the blade are connected. A gas turbine cooling rotor blade, characterized in that the blades are communicated with each other through a connecting hole, and a discharge hole is provided on the surface of the tip shroud, so that cooling air is supplied from an effective part of the blade into the tip shroud.