JPS6148606B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine cooling blade, and more particularly to a turbine cooling blade that can achieve high cooling efficiency with a small amount of air and can even out the metal temperature of the blade.

Turbine blades that are generally used under high-temperature conditions are exposed to high-temperature gas for long periods of time, resulting in severe deterioration.
To prevent this, cooling is performed using air discharged from an air compressor. Such cooling blades are required to sufficiently lower the metal temperature of the blade with a small amount of air, and it is also required to make the metal temperature distribution as uniform as possible in order to reduce thermal stress.

As a countermeasure to these demands, turbine blades are made into thin-walled hollow structures, inserts are provided inside the blades, and air passages are formed between the blade body and the inserts.
Generally, a method was used to cool the blade by blowing cooling air from inside the insert into this air passage. In FIGS. 1 and 2 showing examples of such conventional turbine cooling blades, reference numeral 1 indicates one blade body of a cooling stationary blade of a gas turbine for convenience, and this hollow blade body An insert 2 having a substantially airfoil cross-sectional shape is provided inside the airfoil 1, and an air passage 3 is formed between the airfoil body 1 and the insert 2. An air outlet 5 is provided at the leading edge 4 of the insert 2, and the cooling air sent into the insert 2 is blown out from the outlet 5 and flows through the air passage 3 to the blade dorsal side 6 and the blade ventral side 7. The air is divided into two parts, reaching the trailing edge side 8, and is blown out from an air outlet 9 into the mainstream gas.

However, in a wing with such a structure, the air that cools the leading edge 4 is divided into the wing dorsal side 6 and the wing ventral side 7, so the air required to cool the wing dorsal side and the wing ventral side well is The amount of air will decrease,
As a result, the temperature of the cooling air increases as it moves toward the trailing edge side 8, and the trailing edge side 8 is not cooled much, leading to damage and shortened lifespan due to thermal fatigue of the blade. Therefore, in this type of blade, it is possible to increase the amount of cooling air, but since the cooling air is taken out from the air compressor every minute, the increased amount will be used to directly convert it into power. This is not desirable as it wastes power on the air compressor even though it is not air. Another method is to drill a large number of holes on the leading edge or dorsal side of the wing body and blow out the cooling air into the mainstream, creating a film of cooling air on the surface of the wing body and covering the surface of the wing. It is unsuitable, especially when used in high-temperature gases, because it is uneconomical.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a turbine cooling blade that can solve the above-mentioned problems that conventional turbine cooling blades have and can obtain high cooling efficiency with a small amount of cooling air.

In order to achieve the above object, a turbine cooling blade according to the present invention includes an insert provided inside a hollow turbine blade, an air passage formed between the turbine blade and the insert so as to surround the insert, and an air passage provided in the air passage. In an insert in which air is blown out from inside the insert to cool the turbine blade, the insert is divided into a first insert and a second insert, and the insert is formed by the back side of each insert and the inner wall on the back side of the turbine blade. A protrusion is provided to partition the trailing edge of the flow path into a bag shape, and the connecting rod that divides the flow path into the first insert and the second insert is connected to the air in the height direction of the turbine blade. arranged so as to restrict the flow of
Air exiting from the impingement hole drilled on the wing dorsal side of the first insert and passing through the air passage on the wing ventral side is accelerated by the connecting rod, and the passage of this accelerated air causes the air to pass through the air passageway on the wing ventral side. It is characterized by merging inverted air from the wing dorsal side of the insert into the air passage on the wing ventral side, and then flowing the merging air to the wing trailing edge side.

Embodiments of a turbine cooling blade according to the present invention will be described below with reference to FIGS. 3 to 5, in which the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals. Figures 3 and 4 show for convenience one of the many stationary blades (not shown) protruding from the gas turbine casing, and reference numeral 1 indicates the blade body made hollow. , a first insert 2a and a second insert 2b are provided inside the wing body 1 in series in the direction from the leading edge 4 to the trailing edge 8 of the wing,
An air passage 3 having a constant gap is formed between the blade body 1 and the inserts 2a, 2b so as to surround these inserts 2a, 2b, respectively. A portion of the air passage 3 on the wing dorsal side is partitioned by vertical protrusions 10a, 10b provided on the inner wall of the wing dorsal side at the trailing edges of the first and second inserts 2a, 2b. It is divided into 3a and 3b and has a bag shape. A large number of impingement holes 11 are bored over the entire surface of the blade dorsal side 6 and the blade leading edge side 4 of the insert 2a, and the blade dorsal side 6 of the insert 2b. Further, a connecting rod 12 is provided between the first insert 2a and the second insert 2b so as to separate them.
The connecting rod 12 is a pitch that applies a throttling effect to the air flowing from the first insert 2a, and connects the blade body 1.
are arranged in the height direction. Furthermore, the wing body 1
A large number of pins 13 are provided on the trailing edge side 8 between the wing dorsal side 6 and the wing ventral side 7.

Since the present invention is configured in this way, the cooling air sent from the compressor (not shown) to the inserts 2a and 2b is first passed through the first insert 2a.
The air is blown out into the air passages 3a and 3b from a large number of impingement holes 11 provided on the leading edge side 4 and the blade dorsal side 6 of the blade body 1 and the blade dorsal side 6 of the insert 2b.
The air is blown onto the inner surfaces of the leading edge 4 and the dorsal side 6 of the blade to effectively cool the blade. This blown cooling air is transferred to the air passage 3 due to the projections 10a and 10b.
a, 3b, and flows toward the leading edge toward the wing ventral side 7 as shown by the arrow. The air blown out from the impingement hole 11 reversely flows from the air passage 3a on the blade dorsal side 6 to the air passage 3c on the blade dorsal side 7, and reaches the connecting rod 12 while performing convection cooling. The air passing through this area is subjected to a throttling action, resulting in a high-speed flow.
Attracted by this high-speed air, the air that has been reversed from the second insert 2b joins.
This combined air is disturbed by passing between the many pins 13 at the trailing edge, becomes high speed, enhances the cooling effect, and flows out into the mainstream gas.

It should be noted that the number of divided inserts is not limited to two, and it goes without saying that the same effect can be obtained even if the number of divided inserts is three or more as in the other embodiment shown in FIG.

As is clear from the above description, according to the turbine cooling blade of the present invention, the insert is divided into the first insert and the second insert, and the blade is formed by the back side of each insert and the inner wall on the back side of the turbine blade. A protrusion is provided to make the rear edge of the flow path into a bag shape, and the connecting rod that divides each of the inserts is the first one.
The second insert accelerates the air flowing backwards from the second insert, and the high-speed air attracts the air flowing backwards from the second insert, causing the air to flow toward the trailing edge. Because I did it like this,
Extremely high convection cooling of the blades can be achieved with less cooling air. Therefore, there are great advantages such as increasing the durability of the turbine blade and reducing the degree of damage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a conventional turbine cooling stator vane, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1,
FIG. 3 is a longitudinal cross-sectional view of a turbine cooling stator vane showing an embodiment of the present invention, FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3, and FIG. FIG. 1... Wing body, 2a... First insert, 2
b...Second insert, 3, 3a, 3b, 3c
... Air passage, 4 ... Leading edge, 6 ... Wing dorsal side, 7 ...
... Wing ventral side, 8 ... Trailing edge, 10a, 10b, 10c
... Protrusion, 11 ... Impingement hole, 12 ... Connecting rod, 13 ... Pin.

Claims (1)

[Claims] 1 An insert is provided inside a hollow turbine blade, an air passage is formed between the turbine blade and the insert so as to surround this insert, and air is blown from inside the insert into this air passage to cool the turbine blade. In the above insert, the insert is divided into a first insert and a second insert, and the trailing edge of the flow path formed by the back side of each insert and the inner wall on the back side of the turbine blade is shaped like a bag. In addition to providing a protrusion that partitions the
A connecting rod that divides the first insert and the second insert is arranged so as to restrict the air flow in the height direction of the turbine blade, and a connecting rod is bored on the blade dorsal side of the first insert. The air exiting from the provided impingement hole and passing through the air passage on the ventral side of the wing is accelerated by the connecting rod, and by the induction of this accelerated air, the air from the dorsal side of the wing of the second insert to the ventral side of the wing is accelerated. A turbine cooling blade that is characterized by merging reversed air into a passage and then flowing the merging air toward the trailing edge of the blade.