JPS59122705A - Turbine blade - Google Patents

Abstract

PURPOSE:To perform the cooling of a blade efficiently and uniformly without setting up transparent holes in a blade web part, by installing blowoff holes in a back part of the blade which has cooling passages in its inside, and also installing a lot of blade height directional small holes in the blade web part. CONSTITUTION:Cooling passages 13 are installed inside a turbine blade 11, while blowoff holes 14 are installed in the backside as well as a lot of blade height directional small holes 12 in the blade web side. These small holes 12 open to each of cooling passages 13 at the blade top part. Since no blowoff hole is installed in the blade web side like this, no loading happens there so that the blade web side can be cooled efficiently and uniformly owing to the cooling air passed through these small holes 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a turbine blade, particularly a turbine blade suitable for use in a first stage of a gas turbine exposed to high temperatures.

[Technical Background of the Invention] □ The most effective way to increase the thermal efficiency of a gas turbine is to increase the gas temperature at the turbine inlet.

However, current heat-resistant alloys do not have sufficient ability to withstand thermal stress, high-temperature oxidation, real corrosion, etc. that occur under high-temperature turbine operating conditions, and there is a limit to how high the inlet gas temperature can be raised.

Therefore, various air-cooled turbine blades have been proposed as means for increasing the inlet gas temperature as much as possible.

1 and 2 show typical air-cooled turbine blades.

The turbine blade 1 is hollow, and the interior thereof is divided by a partition wall 2 into a portion from a leading edge 3 to a portion approximately 100 degrees wide, and a portion from the partition wall 2 to a trailing edge 4.

The inner surface of the chamber on the leading edge side is provided with a large number of fins 5 in the application direction and a pan fluro for forming a zigzag flow path, and a through hole 7 for air blowing is provided in the wall of the chamber. ing.

The trailing edge 4 has a slit 8 in the height direction of the wing.
are provided, and the inner surfaces of the walls are connected by pin fins 9.

Cooling air is also supplied through the opening 10 in the blade root, and is blown out from the leading edge and through holes 7 in the blade back to form a film of air for cooling. In addition, the air blown negatively downstream from the rear of the blade from the slit in the trailing edge is cooled by convection. Return flow part 11
In this case, three rows of return flows are performed from the trailing edge of the blade toward the leading edge to achieve convection cooling, and at the same time, cooling is also performed by a film formed by air blown out from the through holes provided in the blade abdomen.

[Problems with background technology]

In the turbine blade having the above configuration, the pressure on the blade vent side is higher than that on the blade back side, and ash, incombustibles, etc. contained in the combustion gas tend to adhere to the blade, and there is a risk that the through holes may be blocked by them. Further, since the pressure distribution on the outer surface of the turbine blade is not uniform, the amount of air blown out from each through hole is different, which tends to cause the temperature distribution on the blade surface to be non-uniform.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to obtain a turbine blade that does not have a through hole for air blowing in the blade or abdomen, and that can provide a good cooling effect.

[Summary of the invention]

In the present invention, a large number of pores are provided in the height direction of the blade from the leading edge of the blade to the entire blade belly, and these pores are communicated with a flow path that communicates with the air blowing hole in the blade spine. A turbine blade is configured to achieve the above objectives.

[Embodiments of the invention]

3 and 4 show an embodiment of the present invention. In these figures, the wall of the turbine blade 11 has a large number of pores drilled from the leading edge to the trailing edge on the blade vent side from the blade root end surface along the wall surface toward the blade top. , which opens into a hollow space, that is, a cooling channel 13, on the blade top side, and the opening is bored toward the blade top.

In the figure, reference numeral 14 indicates an air blowing hole for cooling the film, which is bored on the back side of the wing.

In the turbine blade of the present invention having the above configuration, the leading edge and the wall on the ventral side are cooled by the air flowing from the end face of the blade root, passing through the pores 12, and flowing into the cooling channel 13. .

Therefore, there is no risk of non-uniform cooling due to non-uniform pressure distribution, unlike in the case where a blow-off hole is provided in the blade belly. Furthermore, since no blow-off holes are provided, there is no possibility of clogging of the blow-off holes. Furthermore, since the air flowing into the cooling channel 13 from the pores 12 collides with the inner surface of the blade top wall, it also contributes to cooling the blade top.

Note that the present invention is not limited to the above embodiments.

For example, instead of the pores 12, a zigzag flow path may be formed in the blade vent wall, with one end open to the cooling passage 13 and the other end open to the blade root end surface.

Alternatively, water may be supplied instead of air to the pores or zigzag channels. In this case, the portion where the water flows into the cooling channel 13 may be formed into a nozzle shape, and the water may be blown there to be blown into the cooling channel as steam. Note that the above-mentioned steam is blown out from the blow-off hole 14 together with air to perform film cooling. Also, if a zigzag channel is provided instead of a pore, this R
The passage communicates with the cooling passage 13 at the lower part of the blade, and the cooling water is flooded here, and this steam and the cooling passage 13 are communicated with each other at the bottom of the blade.
Cooling may be performed with air supplied inside.

〔Effect of the invention〕

As is clear from the above, according to the present invention, since the blade does not have an opening on the ventral side where the pressure is high, the risk of the opening being blocked by ash in the combustion gas and non-combustible matter is reduced. Since the coolant flows from the blade root to the blade top, a turbine blade with good and uniform cooling can be obtained.As a result, the temperature of the log gas entering the turbine can be increased, and its thermal efficiency can be improved. be able to.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional gas turbine blade, FIG. 2 is a sectional view taken along the line n-II in FIG. 1, FIG. 3 is a cross-sectional view of an embodiment of the present invention, and FIG. FIG. 3 is a schematic cross-sectional view taken along the IV line. 11...Turbine blade, 12...i hole, 1
3...Cooling channel, 14...Blowout port Application agent Patent attorney Kikuchi Go Department ill/If No. 31I 4 No. 4 @

Claims (2)

[Claims] (1) In a blade having a cooling passage inside the blade, a blow-off hole communicating with the cooling passage is provided in the blade back, and the blade wall extends from the leading edge of the blade to the blade abdomen. A turbine blade characterized in that a large number of pores are bored along the blade wall surface toward the cooling flow path. (2) Claim 1, characterized in that the pores bored toward the cooling flow path open toward the inner surface of the blade top.
Turbine blades described in section.