JPS5925085B2 - Cooling turbine blade structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooled turbine blade used in a high temperature stage of a turbine for a cast turbine engine.

Increasing the turbine inlet gas temperature will contribute to reducing the fuel consumption rate of the gas turbine engine and increasing its output.

On the other hand, in order to adopt a turbine inlet gas temperature that exceeds the operating limit temperature of the super heat-resistant alloy that is the material of the turbine blade, it is necessary to cool the turbine blade to below the operating limit temperature of the turbine blade material.

Practical cooling methods for turbine blades include convection cooling, in which the blade is made into a hollow structure and the cooling fluid from the compressor flows along the inner wall of the blade, impingement cooling, in which the cooling fluid is blown against the wall surface,
There is also film cooling, which also has a heat shielding effect by blowing out cooling fluid onto the outer wall surface of the blade to form a cooling fluid film.

Conventionally, these cooling turbine blades have been molded by casting and machining using a ceramic core that has the shape of a part of the cooling passage, by insert assembly, or by joining the blade halves after the cooling passage has been processed. .

However, the shapes of these cooling passages are specified due to limitations of these processing means, and it has been impossible to manufacture them into a structure that provides optimal cooling performance.

On the other hand, apart from these conventional means, a method has been proposed in which cooling passages are bored in multiple turbine blade pieces and these are joined together, but this method also improves performance by micromachining the cooling passages. However, this method merely imitates conventional cooling passages and does not sufficiently improve the cooling effect.

Therefore, an object of the present invention is to provide a cooling turbine blade structure that has excellent cooling performance by combining a plurality of turbine blade pieces to change the cooling efficiency in the span direction and forming a curved film cooling passage. There is a particular thing.

In cooling turbine blades, the stress that is determined by the inlet gas temperature, support method, and operating conditions generally changes in the span direction, and in order to keep the life until failure as constant as possible in the span direction of the blade, it is necessary to control the cooling efficiency. is preferred.

For this reason, it is possible to improve cooling performance by combining cooling turbine blade segments that do not have cooling passages at several locations in the span direction of the cooling passage and changing the flow rate distribution of the cooling medium in the span direction. be.

According to the present invention, there is a first element in which only the blade center space is formed using a plate material of a heat-resistant alloy, and a element piece in which a cooling passage element is formed in the blade center space and its surroundings using a heat-resistant alloy plate material. and a second elemental piece group in which a plurality of pieces are stacked one on top of the other, the shapes of the cooling passage elements of each elemental piece constituting the second elemental piece group are made to be different from each other, and the cooling passage elements are communicated with each other. A cooling passage communicating with the space and opening on the outer surface of the blade is provided in the second elemental piece group, the first elemental piece is arranged between the second elemental piece group, and these pieces are Construct the wing by diffusion bonding,
The first elemental piece causes the second elemental piece adjacent to the first elemental piece to
Provided is a structure of a cooling turbine blade characterized in that a cooling passage of a group of fragments is blocked.

Embodiments of the invention will be described with reference to the accompanying drawings.

Cooling turbine blade piece 11゜12.13 in Figures 1.2 and 3
By combining the central space 1 and the peripheral wall passage 3 along the outer circumferential surface of the blade, the impingement passage 2 communicates the central space 1 and the peripheral wall passage 3, and further communicates the peripheral wall passage 3 with the outer wall surface of the blade. A cooling passage is constituted by the film cooling passage 4.

This cooling passage is connected in a hierarchical manner by a combination of cooling turbine blade pieces 11, 12, 13, and the cooling fluid passes from the central space 1 through the impingement passage 2, the peripheral wall passage 3, and the film cooling passage 4 to the outer peripheral surface of the blade. leak.

The cooling passage sequentially cools the turbine blade pieces 11 and 12゜1.
3. It changes in the order of 11, 12, 13, 11...

Furthermore, the cooling turbine blade element 14 of FIG. 4 does not have a cooling passage.
The cooling flow rate in the span direction of the cooling turbine blade can be changed to achieve appropriate cooling characteristics by inserting the Obtainable.

A cooling turbine blade piece including such a cooling passage is formed by machining, photoetching, laser processing, or the like.

In particular, cooling passages may be provided with constrictions, protrusions, and depressions in consideration of the pressure, heat transfer coefficient, and stress on the outer wall surface of the blades, and may have a wavy, step-like, or
It is also possible to form it in a meandering manner.

Furthermore, the dimensions of the cooling passage are determined so that the pressure difference between the cooling pressure in the central space and the blade outer surface pressure is controlled by pressure loss due to impingement cooling and pressure is regulated by convection cooling so that the film blows out at an appropriate film cooling rate. This makes it possible to obtain the optimum cooling effect.

Furthermore, it is preferable that the film cooling passages of the cooling turbine blade pieces 11, 12, and 13 be inclined in the flow direction on the outer surface of the blade, but in the past, holes were only formed in a straight line because electrical discharge machining, electrolytic machining, laser machining, etc. were performed after casting. I couldn't process it.

However, in a cooling turbine blade constructed by diffusion bonding cooling turbine blade pieces, the film cooling passage can be processed into a curved shape, so the cooling fluid is blown out close to the blade surface, resulting in less turbulence in the mainstream and pressure loss. low and high heat rejection,
It has a structure with excellent aerodynamic performance, cooling performance, and strength performance due to the small decrease in strength.

5 shows a part of a cooling turbine blade to which these cooling turbine pieces are joined.

[Brief explanation of the drawing]

1.2 and 3 show examples of cooling turbine blade segments 1L12 and 13 having cooling passages. The cooling passage 2.3.4 carries the cooling turbine blade segment 11.12.
By combining them in the order of 13, they communicate with the central space 1 and the outer wall surface of the blade. FIG. 4 shows an example of a cooling turbine blade segment 14 without a cooling passage. Figure 5 shows the cooling turbine blade element 11 in Figures 1.2 and 3.4.
, 12.degree. 13.14. FIG. In the figure, 1 is the central space 2, and 3.4 is the cooling passage.

Claims (1)

[Claims] 1. A first piece in which only the blade center space is formed using a heat-resistant alloy plate, and a plurality of pieces in which a heat-resistant alloy plate is used to form the blade center space and cooling passage elements around it. a second elemental piece group, the shapes of the cooling passage elements of the respective pieces constituting the second elemental piece group are made to be different from each other, and the cooling passage elements are communicated with each other in the space portion. A cooling passage that communicates with and opens to the outer surface of the blade is provided in the second elemental piece group, and the first elemental piece is arranged between the second elemental piece group,
A cooling method characterized in that these pieces are diffusion bonded to form a wing, and the first piece blocks a cooling passage of the second group of pieces adjacent to the first piece. Turbine blade structure.