JPH0833099B2 - Turbine blade structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a turbine blade structure for enhancing cooling efficiency of a turbine blade.

[Prior Art] Generally, a gas turbine such as a jet engine of an aircraft is driven by a hot working gas. Since the moving blades and stationary blades of this gas turbine are brought into contact with the high-temperature working gas, cooling gas is circulated in the blade body in order to prevent these blade bodies from reaching a temperature higher than a predetermined temperature. It is known.

Compressed air from a compressor is used as this cooling fluid. Since this compressed air is directly related to the efficiency and output of the turbine, cooling is performed by efficiently contacting the blade body with as little compressed air as possible. There is a need. for that reason,
Protruding members are provided for cooling the entire surface of the blade body by forming a folded channel for circulating the cooling gas in the blade body, and for providing a turbulent flow to this channel.

Conventionally, as shown in FIGS. 6 and 7, this wing body 1
A series of flow paths 2 that have been folded back are formed between the blade root portion 5 and a large number of discharge holes 3 provided near the blade head. It is supposed to be done. The side wall 7 of the flow path 2 and the side wall 7a on the opposite side of the side wall 7 are provided with a protruding member 8 for giving a turbulent flow to the circulating cooling gas.

The projecting member 8 is a straight column member having a rectangular cross section, which is at an angle α with the flow direction of the cooling gas and has a front side 8a to a rear side 8b.
And is provided on the side wall 7 in multiple stages at appropriate intervals. A gap 6 that prevents dust of the cooling gas 4 from accumulating is formed at a predetermined portion of the protruding member 8.

The flow of the cooling gas flowing through the flow path 2 is disturbed by the protruding members 8 provided on the side walls 7, 7a, and the side walls 7, 7a and
The degree of contact with 7b is increased, and the cooling efficiency of blade body 1 is increased. (For example, U.S. Pat.
In addition, while the above-mentioned protruding member 8 is provided so as to be inclined in one direction of the side walls 7,7a, as shown in FIG. There is also known a turbine blade structure provided with a projecting member 9 that is formed by two members 9a and 9b that are inclined toward each other at an angle α and that are joined at this center line.

[Problems to be Solved by the Invention] In the turbine blade structure described above, since the turbulent flow can be given to the cooling gas by providing the projection members 8 on the sidewalls 7 and 7a, the sidewalls in contact with the projection members 8 can be provided. A secondary flow of cooling gas will occur downstream of 7,7a. This secondary flow acts to separate the cooling gas from the side walls, prevent them from coming into contact with each other, and reduce the cooling effect of the blade body.

As shown in FIGS. 9 and 10, the secondary flow generated on the front side 8a of the projecting member 8 is pushed toward the rear side 8b of the projecting member 8 together with the flow of the cooling gas, and the rear side It will be integrated in 8b. Therefore, the front side of the protruding member 8
Although a secondary flow occurs on the side walls 7 and 7a downstream of 8a,
The secondary flow is rarely accumulated, and the cooling gas is
Adhesion region A having a high heat transfer coefficient is generated by being in good contact with 7a, and blade body 1 in this portion is cooled.

However, the secondary flow generated on the front side 8a of the projecting member 8 flows toward the rear side 8b together with the flow of the cooling gas, and is integrated on the downstream side of the rear side 8b together with the secondary flow generated on the rear side 8b. Will be done. Therefore, the secondary flow accumulated on the downstream side of the rear side 8b causes a separation area B having a low heat transfer coefficient that hinders the contact between the cooling gas and the blade body 1. This will result in insufficient cooling.

Therefore, although the turbulent flow can be generated in the circulating cooling gas 4 by providing the protruding member 8 on the side walls 7, 7a of the flow path 2 in an inclined manner, the heat is uniformly generated from the high-temperature blade body 1. It was difficult to absorb. Therefore, high and low parts are generated in the cooling of the blade body 1 and hot spots in which the cooling is insufficient are partially generated, so that not only the cooling efficiency by the cooling gas fed into the flow path 2 cannot be improved, but also the heat resistance of the blade body 1 is improved. There was a problem of shortening the life.

Also, as shown in FIG. 8, two members are provided on the side walls 7, 7a.
In the projecting member 9 in which 9a and 9b are joined at the center line of the side walls 7 and 7a, the secondary flow is accumulated toward the top portion 10 which is the joining portion of the projecting member 9 and a large separation area C is generated. Protruding member 8
It had the same problem as.

The present invention has been made to solve the above problems, and an object of the present invention is to suppress the generation of a cooling gas separation region on the downstream side of a protrusion member provided in a flow path of a blade body. In order to bring a cooling gas into contact with the entire blade body, it is possible to provide a blade structure capable of uniformly cooling the blade body.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention forms a cooling gas passage through which a cooling gas passes inside a turbine blade, and forms a cooling gas passage at the front and rear edges of the turbine blade after cooling from the passage. In a turbine blade structure in which exhaust holes for discharging gas are formed, the cooling gas passage is formed in a rectangular cross section, and the central portion passes through the passage on both inner walls of the cooling gas passage that face each other. A plurality of fins are provided at predetermined intervals along the longitudinal direction of the passage, the fins having arcuate surfaces that bulge on the downstream side of the cooling gas, and both ends of which are connected to the inner walls of the passage.

[Operation] Compressed air from the compressor is circulated as cooling gas in the blade body that has been brought into contact with the hot working gas and has become hot.

This cooling gas is fed into the cooling gas passage from the root of the blade to the blade and is circulated so as to cool the blade, and the cooled gas is discharged at the front and rear edges of the blade. It is discharged from the hole. At the same time, this cooling gas is brought into contact with fins provided on the side wall of the passage to give a turbulent flow and enhance the contact with the side wall of the blade body.

When the cooling gas comes into contact with the fins, a secondary flow of the cooling gas is generated on the downstream side in contact with the fins, and the cooling gas is separated from the side wall by the secondary flow, which impedes the cooling action of the blade body. Trying to be done.

The fins provided on this side wall are symmetrically provided with respect to the center line of the passage and have a curved arc surface that is bulged on the downstream side of the cooling gas. Therefore, the secondary flow generated on the downstream side in contact with this fin does not flow out to the downstream side portion of another fin or is not accumulated, and stays in a very narrow portion on the downstream side, and the cooling gas The spread of the peeling area stops in a very narrow downstream portion defined by the fin and the inner wall of the passage.

As a result, a secondary flow that prevents contact between the sidewall and the cooling gas is generated on the downstream side of the fin provided on the side wall of the passage, but this secondary flow is suppressed from accumulating and spreading, and the cooling gas is suppressed. Can be brought into contact with the entire blade body, and the blade body can be efficiently cooled with a small amount of cooling gas.

Embodiment A preferred embodiment of the present invention will be described with reference to the drawings.

In the blade body 11 according to this embodiment, as shown in FIGS. 1 to 3, passages 13 for cooling gas for cooling the blade body 11 are formed. This passage 13 is at the base of the wing body 11.
The passage portion 13a for circulating the cooling gas fed from the cooling gas feeding hole 20 of 12 to the front discharge holes 15 and the top discharge holes 16 formed in the blade leading edge portion 14, and the feeding of the root portion 12 A large number of cooling gases sent from the holes 21 are formed in the blade trailing edge portion 18 and then discharged.
19 and a passage portion 13b which is folded back in multiple stages and communicates with the top discharge hole 16. These passages 13 are side walls 2
It is formed in a rectangular shape with an arbitrary aspect ratio of the cross section across 4. The fins 26 are formed on the four side walls 24 forming the passage 13.
Fins are provided on the 1st to 4th surfaces in multiple stages over the entire length thereof at intervals p.

The fin 26 is a member having a rectangular cross section in which an arc surface having a radius of curvature r is formed, and the fin surface 26 is provided so as to be located on the downstream side of the passage 13 so as to cover the entire width of the side wall 24. The cross-sectional shape of the fin 26 is not limited to a square shape, and may be another shape.

The height e of the fin 26 is determined by the width and height of the passage 13 and the radius of curvature r, and the interval p between the fins 26 is preferably 5 to 20 times the height e of the fin 26.

Each end 27 of each fin 26 has a side wall.
It is provided on the side wall 24 at a contact angle α with a plane orthogonal to the center line X of 24. Therefore, the fins 26 are provided so as to be symmetrical with respect to the center line of the side wall 26. This contact angle α is 0 °
It is selected within the range of <| α | ≦ 45 °.

Further, as shown in FIG. 4, the fin 26 may be provided with a notched gap 30 at a predetermined position in order to prevent dust in the cooling gas from being accumulated in the fin 26.

 Next, the operation of this embodiment will be described.

In order to cool the blade body 11 that has been brought into contact with the hot working gas and has a high temperature, the compressed air from the compressor is circulated as the cooling gas in the passage 13 of the blade body 11.

This cooling gas is a cooling gas inlet hole at the root 12 of the blade.
From 20 to the front discharge hole 15 and the top discharge hole 16 of the blade leading edge 14 of the wing body 11
To the passage portion 13a that communicates with the rear discharge hole 19 and the top discharge hole 16 of the trailing edge portion 18 of the blade body 11 from the feed hole 21.

That is, the cooling gas introduced into the blade body 11 from the inlet hole 20 passes through the passage portion 13a to cool the leading edge side of the blade body 11,
The cooled gas is discharged from the top discharge hole 16 provided at the tip of the blade and the front discharge hole 15 provided at the front edge. Further, the cooling gas introduced into the blade body 11 from the feed hole 21 cools the trailing edge side of the blade body 11 through the passage portion 13b, and the cooled gas is a front discharge hole provided at the trailing edge portion. It is discharged from 19 and a top discharge hole 16 provided at the tip of the blade.

This circulating cooling gas is brought into contact with the side wall 24, and the blade body 11
Is cooled. Along with this, the cooling gas flows through the side wall of the passage 13.
An arcuate surface R that is provided on the downstream side of the cooling gas and is provided on 24
Is contacted with the formed fin 26. The contact with the fins 26 gives a turbulent flow to the flow of the cooling gas and enhances the contact for cooling the side wall 24 of the blade body 11.

When the cooling gas comes into contact with the fins 26, a spiral secondary flow is generated on the downstream side in contact with the fins 26. This secondary flow exists between the flow of the cooling gas and the side wall 24 and separates the cooling gas from the side wall 24, so that it tries to act so as to hinder the cooling of the blade body 11. Therefore, when the secondary flow is accumulated on the downstream side of the fin 26, a wide separation area is generated, which causes uneven cooling of the blade body 11.

The fins 26 provided on the side wall 24 in the present embodiment are provided symmetrically with respect to the center line X of the passage 13 and have an arcuate surface R that is bulged on the downstream side of the cooling gas. Since they are respectively connected to the passage side walls 24 on both sides thereof, as shown in FIG. 5, the secondary flow generated on the downstream side in contact with the fin 26 may flow while being deflected from the flow direction of the cooling gas. Absent. Therefore, this secondary flow is part of the downstream side of the fin 26 (the fin 26 and the passage side wall 24
It is suppressed that the separation area of the cooling gas, which is accumulated in the downstream side very narrow portion divided into and, is expanded.

Thereby, the adhering areas D of the cooling gas having high heat transfer are generated on both sides of the center line X of the passage 13, and the side wall 24 as a whole has a wide adhering area on average. Improved and excellent cooling effect can be obtained.

[Advantages of the Invention] According to the present invention, the fins formed on the side wall of the passage of the wing body 2
It is possible to prevent the secondary flow from accumulating and expanding, and to allow the cooling gas to come into contact with the entire blade body evenly, so that the blade body can be efficiently cooled with a small amount of cooling gas.

[Brief description of drawings]

FIG. 1 is a sectional view of a wing body of an embodiment according to the present invention, and FIG.
1 is an enlarged explanatory view of the passage of the cooling gas in FIG. 1, FIG. 3 is a view taken along the line XX of FIG. 2, FIG. 4 is an explanatory view of a modified example, and FIG.
FIG. 6 is an explanatory view of a fin according to the present invention, FIG. 6 is a cross-sectional view of a blade body according to the prior art, and FIG. 7 is an enlarged view of a main part of FIG.
FIG. 8 is an explanatory view of another prior art, and FIGS. 9 and 10 are explanatory views of the operation of FIG. In the figure, 11 is a turbine blade, 13 is a cooling gas passage, 15 is a front discharge hole, 19 is a rear discharge hole, 24 is a side wall, and 26 is a fin.

Continuation of front page (56) References JP-A-60-135604 (JP, A) JP-A-62-85102 (JP, A) JP-A-60-101202 (JP, A) JP-A-61-1805 (JP , A) JP 62-271902 (JP, A) JP 58-126402 (JP, A) JP 61-187501 (JP, A) JP 60-135604 (JP, A) JP 64-66401 (JP, A) JP-A-2-11801 (JP, A)

Claims (1)

[Claims] 1. A turbine blade in which a cooling gas passage for passing a cooling gas is formed inside the turbine blade, and exhaust holes for exhausting the gas after cooling from the passage are formed in front and rear edges of the turbine blade, respectively. In the structure, the cooling gas passage is formed to have a rectangular cross section, and both ends of the cooling gas passage have arcuate surfaces whose central portion is bulged toward the downstream side of the cooling gas passing through the passage. A turbine blade structure, wherein a plurality of fins, each of which is connected to the inner wall of the passage on both sides thereof, are provided at predetermined intervals along the longitudinal direction of the passage.