JPH08135401A - Gas turbine air cooled blade and its manufacture - Google Patents

Abstract

PURPOSE: To improve film cooling efficiency by providing a groove on an inner surface side of a blade material and drilling a plural number of film cooling holes on the downsream in the flowing direction of main stream gas from this groove with an angle nearly in parallel with an outer surface of the blade material from a stepped part lowered toward the downstream of the outer surface of the blade material. CONSTITUTION: A groove 2 orthogonal with the flowing direction F of main stream gas is provided on an inner surface side of a blade material 1 as a gas turbine air-cooled blade. Thereafter, a plural number of film cooling holes 3 communicating with the groove 2 at an angle nearly in parallel with an outer surface of the blade material 1 are drilled on a stepped part 4 provided in the downstream from the groove 2 on the outer surface of the blade material 1. Consequently, as film air is blown out toward the downstream roughly in parallel with the flowing direction of the main stream gas from a plural number of the film cooling holes 3, it is possible to most suitably regardless of blowing out strength. Additionally, the blown out film air flows crawling on the outer surface of the blade material 1 and covers the blade with a cooling film and performs efficient cooling of the blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine air cooling blade capable of effective film cooling and a method of manufacturing the same.

[0002]

2. Description of the Related Art In an air-cooled moving vane of a gas turbine,
Various cooling techniques such as impingement cooling, film cooling, and shower head cooling have been introduced. Among them, film cooling has become an indispensable technique in the air cooling blade of the high temperature gas turbine. As shown in FIG.
1 drilled on the outer surface of the cylinder in the direction of mainstream gas flow
The cooling efficiency is improved by blowing cooling air from 1 to cover the blade surface as shown by the arrow.

In this cooling system, it is impossible to blow the air on the surface of the blade having a high pressure with the cooling air having a low pressure. Therefore, the air is blown at an appropriately high pressure.

[0004]

In the film cooling of the conventional gas turbine air cooling blade described above, if the cooling air is blown out too strongly, the cooling air mixes with the mainstream gas, and the original effect of the film cooling may be exhibited. Absent. In other words, in film cooling, optimization of how strong the cooling air is blown to firmly cover the blade surface becomes a problem.

The present invention has been made to solve this problem.

[0006]

[Means for Solving the Problems]

(1) The gas turbine air-cooling blade of the present invention is provided with a groove on the inner surface side of the blade material, and the blade is located from a step portion located downstream of the groove in the flow direction of the mainstream gas and down to the downstream of the outer surface of the blade material. It is characterized in that a plurality of film cooling holes communicating with the groove are formed at an angle substantially parallel to the outer surface of the material. (2) In the method for manufacturing a gas turbine air-cooling blade of the present invention, the first step is to cast a blade material by using a ceramic core having projections that are male patterns of the groove on the surface and form the groove on the inner surface side of the blade material. And a second step of forming a plurality of film cooling holes that communicate with the groove on the inner surface side from the outer surface of the blade material downstream of the groove in the flow direction of the mainstream gas.

[0007]

In the gas turbine air-cooling blade of the present invention, since the outer surface of the blade material and the film cooling hole, which is the outlet of the cooling air, have an angle close to parallel, the flow of the mainstream gas is almost parallel to the mainstream gas. The film air is blown out in the downstream direction. Therefore, it is not necessary to adjust the blowing strength of the cooling air to search for the optimum point, and the blown film air flows almost parallel to the mainstream gas so as to crawl on the outer surface of the blade material to cover the blade with the cooling film. Effective blade cooling can be performed.

Further, according to the cooling method of the gas turbine air-cooling blade of the present invention, the inner surface side of the blade material is cast-molded by using the ceramic core, and the outer surface of the blade material is subjected to a plurality of machining processes such as electric discharge. The film cooling holes of are being drilled,
No manufacturing difficulties.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

A groove 2 which is orthogonal to the flow direction F of the mainstream gas is provided on the inner surface side of the blade material 1 of the gas turbine air-cooling blade,
On the downstream side of the groove 2 on the outer surface of the blade 1 in the flow direction F of the mainstream gas, there is provided a step portion 4 which is orthogonal to the flow direction of the mainstream gas and forms a substantially right angle toward the downstream side. . A plurality of film cooling holes 3 communicating with the groove 2 from the step portion 4 at an angle nearly parallel to the outer surface of the blade material 1 are formed in the blade material 1.

Due to the groove 2 and the plurality of film cooling holes 3, the cooling air enters the groove 2 from the inside of the blade, passes through the plurality of film cooling holes 3 and is almost in the flow direction F of the mainstream gas as shown by an arrow A. In parallel, the film air is blown downstream. In this way, the film air is blown toward the downstream side substantially parallel to the flow direction F of the mainstream gas from the plurality of film cooling holes 3 in the step portion 4 on the outer surface of the blade member 1. Regardless of, the film air can be blown out optimally. Further, as shown in FIG. 2, the blown-out film air flows substantially parallel to the mainstream gas so as to crawl on the outer surface of the blade material 1 to cover the blade with a cooling film to effectively cool the blade. You can

In manufacturing the gas turbine air-cooling blade described above, as shown in FIG. 1 (a), a step is formed by using a ceramic core (core) 6 having a projection 5 which is a male type of the groove 2 on the surface. A blade material 1 having an outer surface having a portion 4 is cast, and at the same time, a groove 2 is formed upstream of the step portion 4 in the flow direction of the mainstream gas. As the material of the ceramic core 5, usually ceramic can be used. Then, a plurality of film cooling holes 3 communicating with the groove 2 from the outer surface side of the blade material 1 are drilled by machining such as electric discharge.

As described above, since the blade material 1 of the air cooling blade of the present gas turbine is cast on the inner surface side by using the ceramic core 6, and the blade material 1 is provided with a plurality of film cooling holes, Its manufacture is extremely easy.

[0014]

The gas turbine air-cooling blade of the present invention described in claim 1 does not require optimization of the blowing strength of the film air for cooling the blade, and simplifies the design. High film cooling efficiency is obtained and its reliability is improved.

Further, according to the method of manufacturing the gas turbine air-cooling blade of the present invention described in claim 2, the gas turbine air-cooling blade of the present invention can be easily manufactured.

[Brief description of drawings]

1A and 1B show an embodiment of the present invention, FIG. 1A is an explanatory view of a manufacturing process of the embodiment, and FIG. 1B is a perspective view of the embodiment.

FIG. 2 is an explanatory diagram of a state of film cooling in the example.

FIG. 3 is a cross-sectional view of a conventional film cooling type gas turbine air cooling blade.

[Explanation of symbols]

 1 wing material 2 groove 3 film cooling hole 4 step 5 projection of ceramic core 6 ceramic core A film air flow direction F main flow gas flow direction

Claims (2)

[Claims] 1. A groove is provided on the inner surface side of the blade material, and is parallel to the outer surface of the blade material from a step portion located downstream of the groove in the flow direction of the mainstream gas and descending toward the downstream of the outer surface of the blade material. A gas turbine air-cooling blade, wherein a plurality of film cooling holes having a close angle and communicating with the groove are formed. 2. A first step of casting a blade material by using a ceramic core having a projection serving as a male shape of a groove on the surface to form a groove on the inner surface side of the blade material, and a flow direction of a mainstream gas from the groove. A method for manufacturing a gas turbine air-cooling blade, comprising a second step of forming a plurality of film cooling holes communicating from the outer surface of the downstream blade material to the inner surface side groove.