JPS60182302A - Gas turbine cooling blade - Google Patents

Abstract

PURPOSE:To improve cooling performance by forming a cooling passage making at least one reciprocating lead in the blade height direction on an insert in a blade and connecting the passage to a cool air duct between the inner wall of the blade and the insert. CONSTITUTION:A cooling passage 3 which makes at least one reciprocating lead in the blade height direction as shown by arrows is formed on an insert 2 in a blade. The cooling passage 3 is connected to a cool air duct 6 between the inner wall 1 of the blade and the insert 2, and the cool air is discharged from cooling holes on the rear edge of the blade. Thus, larger heat transfer rate can be realized in the cooling passage 3 of the insert 2 to improve cooling performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to turbine blades, and particularly to industrial turbine blades.
It relates to turbine blades requiring cooling, such as those used in the first stage of an engine.

[Prior art and its problems]

Turbine engines and the like generally employ a self-propelled drive system in which the turbine itself, which is driven by combustion gas, drives a blower or compressor that supplies air to a combustor. In order to increase the output efficiency of such a turbine,
The most effective method is to increase the temperature of the combustion gas at the turbine inlet, but this temperature is limited by the thermal stress resistance of the materials forming the turbine blades or their ability to withstand high temperature oxidation, corrosion, etc.

Therefore, conventionally, a convection type turbine blade is used, which has a flow path through which a cooling fluid flows inside the blade. However, in this conventional turbine blade, the amount of cooling fluid used to maintain the turbine blade temperature within an allowable value is too large for a given turbine inlet gas temperature, and the amount of cooling fluid used is unsatisfactory. It wasn't. That is, a large amount of cooling fluid obviously lowers the temperature of the blade, but conversely increases the aerodynamic loss of the blade and also reduces the turbine output efficiency.

For this reason, the current situation is that there is a desire for the development of a device that can effectively cool the blades with a small amount of cooling fluid.

In addition, in order to maintain good cooling performance even when using poor-quality fuel containing impurities, we do not provide so-called film cooling holes on the blade surface, especially at the leading edge. Wings are desired.

Conventional cooling blades with film cooling holes and mainly convection cooling have an insert inside the blade, a cold air duct between the outer cover of the insert and the inner wall of the blade, and the cooling fluid is directed to one place in the insert or Many examples have been considered in which cold air flows into a cold air duct from several locations through a turbulence chamber made up of an insert and the inner wall of the blade, or directly into a cold air duct and flows out of the blade. However, in these structures, as the cooling fluid flows along the cooling duct, the temperature of the cooling fluid increases, which tends to cause unevenness in the temperature of the blade surface.

In addition, the main purpose of the connection between the insert and the inner wall of the blade is to form a cooling duct, and the cooling flow path inside the insert is a blenheim with a relatively large cross-sectional area, so the heat transfer coefficient is low. However, there is a drawback that the cooling effect of heat conduction due to the connection between the protrusion of the insert and the inner wall of the blade is small.

Furthermore, conventional inserts are elastic and are made of a different material from the wings, and are manufactured separately, and in many cases, the assembly process involves inserting the inserts into each wing one by one.

[Object of the present invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a cooling blade for a gas turbine that has high cooling performance and is relatively easy to manufacture.

[Summary of the invention]

The present invention belongs to a conventionally known type of cooling blade that has an insert inside the blade and forms a cold air duct with the protrusion of the insert's outer cover and the inner wall of the blade. It has very distinctive characteristics.

In other words, in the conventional type, the cooling flow path inside the insert has a relatively large cross-sectional area and is a plenum, so the heat transfer coefficient inside the insert is low, and the connection between the protruding part of the insert and the inner wall of the blade is also a cold air duct. The main purpose is to form a blade, and there is almost no cooling effect of heat conduction due to the connection between the insert protrusion and the blade inner wall. In contrast, in the present invention, the cooling channel in the insert is a return flow channel that reciprocates at least once in the blade height direction, and after the cooling fluid flows through the return flow cooling channel in the insert, The cold air flows through a perforation in the tip of the insert or elsewhere into a turbulent chamber that leads to a cold air duct consisting of a protrusion on the insert jacket and the inner wall of the blade.

〔Effect of the invention〕

According to the present invention, the cooling fluid first flows through the return-flow cooling channel within the insert, and unlike the conventional plenum-type cooling channel, the cooling channel within the insert achieves a large heat transfer coefficient. As a result, the cooling effect of heat conduction due to the connection between the protrusion of the insert jacket and the inner wall of the blade is significantly increased.

Furthermore, if the flow direction of the cooling fluid flowing through the cooling channel inside the insert body and the flow direction of the cooling fluid flowing through the cold air duct constituted by the protrusion of the insert body jacket and the blade inner wall are reversed,
Heat exchange occurs between the cooling fluid in the cooling flow path and the cooling fluid in the cold air duct, making it possible to uniformly cool the blades.

[Embodiments of the invention]

Examples of the present invention will be described below. Figure 1 is a cross-sectional view in the cord direction, Figure 2 is a cross-sectional view taken along the line I-I in Figure 1, and Figure 3 is a cross-sectional view taken along the cord direction.
The figure is a sectional view in the span direction, and FIG. 4 is a perspective view of the insert.

In this embodiment, there are five cooling channels in the insert in the span direction, and the cooling fluid flows in from the trailing edge side.
A turbulent flow chamber is provided at the leading edge, the cold air flows through a duct, and finally flows out of the blade through a perforation provided at the trailing edge of the blade.

The cooling fluid enters through the cooling fluid inlet 10 as shown in FIG. It flows while returning, and flows out into the turbulent flow chamber 6 through the perforation 5 provided in the insert body 2. Thereafter, as shown in FIG. 1, the air flows through the cooling duct 7, passes through the cooling holes 8 provided at the trailing edge, and flows out to the blade row.

By the way, the cold air duct 7 is constructed by joining the inner wall of the blade 1 and the protrusion 9 of the insert body 2, as shown in FIG. wing 1
The inner wall and the protrusion 9 are joined to each other so as to have a good heat conduction effect.

This is a technology that is fully possible with diffusion bonding and precision casting technology.

[Other embodiments of the invention]

In other embodiments of the invention, the cooling channels in the insert 2 can be divided into two or more parts, as shown in FIG. In this example, there are two cooling fluid inlets.
One side flows toward the leading edge through the perforation 5 into the turbulent flow chamber 6, and then passes through the cold air duct and flows out to the trailing edge;
Another system has a perforation 5 also provided on the rear edge side of the insert body 2, and the flow directly flows out from the rear edge. This example has a structure with pin fins 11 at the rear edge.

Further, the perforations 5 leading from the insert 2 to the cold air duct 7 can be provided not only on the leading edge side and the trailing edge side of the insert body 2, but also at arbitrary locations depending on the cooling performance of the blade.

It is also possible to form the protrusion 9 of the insert 2 into a pin-fin structure.

[Brief explanation of the drawing]

1 is a sectional view in the cord direction of an embodiment of a cooling blade according to the present invention, FIG. 2 is a sectional view in the span direction of the cold air duct in FIG. 1, and FIG. 3 is a sectional view in the span direction of the cold air duct in FIG. 1. 4 is a perspective view of the insert of the present invention, and FIG. 5 is a sectional view of another embodiment of the rod invention. DESCRIPTION OF SYMBOLS 1... Wing, 2... Insertion body, 3... Cooling channel in insert body, 4... Return part in insert body, 5... Perforation in insert body, 6...・Turbulence chamber, 7...cold air duct, 8
...Cooling hole, 9...Protrusion, 10...Cooling fluid inlet, 11...Pin fin. Agent Patent Attorney Kensuke Chika (and 1 other person) 2nd
Figure JP-A-182302 (4) Figure 5 No. 11

Claims (2)

[Claims] (1) A gas turbine cooling blade having a hollow structure in which cooling fluid flows into the blade from the blade root, passes through the blade effective part and flows out of the blade, and has an insert inside the blade, and The insert jacket has a number of protrusions that connect with the inner wing wall to form cold air ducts, and the insert has perforations at the tip or other locations to connect with the inner wing wall. A turbulent flow chamber communicating with the cold air duct is formed between the insert and the cold air duct, and the cold air duct communicates with the outside of the blade through a perforation provided at the trailing edge of the blade or elsewhere, and the insert body is configured to extend in the blade height direction. A gas turbine cooling blade characterized in that it has a cooling passage that reciprocates at least once and communicates with the turbulence chamber through a hole provided at the tip of the insert or elsewhere. (2) The gas turbine cooling blade according to claim 1, further comprising a protrusion on the inner wall of the blade to form a cold air duct.