JPS6332103A - Blade of gas turbine - Google Patents

Abstract

PURPOSE:To enable cooling to be performed efficiently by the use of cooling air in a small quantity by providing two inserts to be inserted into a blade, and then keeping cooling passages separate. CONSTITUTION:Two inserts 3, 4 are placed in the casing 1 of a blade. One insert 3 of the two is provided with a blowhole 15, cooling air ducts 6, 7 and laminar cooling blowholes 8, 9. The other insert 4 is provided with blowholes 15, 16, cooling air ducts 13, 14 and laminar cooling blowholes 17, 18. By keeping cooling-passages separate in the front part and the rear part respectively, the temperature rise in the cooling air can be suppressed, and therefore, cooling can be performed efficiently by the use of cooling air in a small quantity.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) This invention relates to gas turbine blades.

(Prior Art) In recent years, in order to improve the performance of gas turbines, each blade has been exposed to higher temperatures due to the increase in gas temperature, and as the blades have become larger, the blades themselves have also become larger. As shown in Japanese Patent Application Laid-Open No. 51-69707, the blades used in the past blow out from the tip of the insert into the turbulent flow chamber, branch out, pass through the cold air ducts on the ventral and dorsal sides, and exit at the trailing edge of the blade. It had a configuration in which it merged at the end and blown out from the trailing edge. In such blades, under certain conditions, i.e. when the cooling air is relatively small and the temperature on the outside of one blade is exposed to a high temperature, the entire area of the blade is uniformly and sufficiently It is difficult to achieve adequate cooling. Furthermore, as the size of the cooling air duct increases, the temperature of the cooling air flowing through the cold air duct increases, which is another factor that prevents sufficient cooling from being achieved. Therefore, in order to keep the temperature of one blade below an allowable value, a large amount of cooling air is required. If the flow rate of cooling air is large, 1
Although the ability to lower the temperature of the blades is improved, on the other hand, the average gas temperature decreases due to an increase in the amount of cooling air mixed with the mainstream gas, which may cause problems such as a decrease in the output efficiency of the gas turbine. Ta.

(Problem that the invention aims to solve) Even when the outside temperature of the blade is exposed to high temperature, the temperature rise of the cooling air flowing in the cold air duct can be suppressed, and the cooling air can be used in a considerable amount in all ranges. The objective is to provide a gas turbine blade that is able to achieve as much uniform and sufficient cooling as possible.

[Structure of the invention]

(Means for solving the problem) At least two inserts are provided, one of which has laminar cooling air holes that pass through the cold air duct from its tip and communicate with the cold air duct on the side wall surface of the jacket. In addition, in the other insert body, an air hole is bored in the side wall surface of the insert body to communicate with the cold air duct. A cooling channel in which laminar cooling air holes communicating with the cold air duct are bored is provided in the cooling channel, and the cooling channels are separated.

(Function) By separating the cooling flow path into, for example, the front and rear parts, it is possible to suppress the temperature rise of the cooling air flowing in the cold air duct, and as a result, it is possible to suppress the temperature rise of the cooling air flowing in the cold air duct, and as a result, it is possible to suppress the temperature rise of the cooling air flowing in the cold air duct. , can achieve almost uniform and sufficient cooling.

(Example) Examples of the present invention will be described below. FIG. 1 shows a cross-sectional view of the internal structure of the blade of the present invention.

The outer sheath 1, which has the stable shape necessary for the blade and mechanical strength due to the ribs 2, has an internal cavity delimited by the ribs 2, and some of the cavities follow the shape of the outer envelope. Front insert 3
and a rear insert 4 introduced from the outside and firmly connected to the shroud on the underside. The front insert 3 is the jacket 1
The side wall of the insert body contacts the protrusion JF5 5 extending in the chord direction existing on the inner wall of the outer cover 1 to form a cold air duct 6.7 between the protrusions 5. There is. In addition, laminar cooling air holes 8 and 9 communicating with the cold air ducts h6 and 7 are bored on the surface of the side wall of the jacket 1 on the downstream side of the cold air duct 6.7 separated by the rib 2. . The cooling air that has passed through the interior of the insert 3 passes through an air hole 10 drilled at the tip of the insert 3, branches through a turbulence chamber 11, and enters the dorsal and ventral cold air ducts 6.7. Flowing through the cold air duct6.
7. Air is ejected from laminar cooling air holes 8 and 9 provided in the outer cover 1 on the downstream side, and cools the area after the holes 8 and 9. The rear insert 4 is
The insert side wall is placed after the rib 2 of the skin 1, and the insert side wall touches a chordwise extending projection 12 present on the inner wall of the skin 1, so that a cold air duct 13, 14 is formed between the projections 12. is forming. In addition, a cold air duct 13 is provided on the side wall surface of the insert body 4.
Air holes 15.16 are drilled in the side wall of the jacket 1, communicating with the cold air duct 13.14, and laminar cooling air holes 17.18 are drilled in the side wall surface of the jacket 1, communicating with the cold air duct 13.14. The cooling air that has passed through the interior of the insert 4 flows through a cold air duct 13.14 through respective air holes 15.16 provided in the dorsal and ventral side walls of the insert 3, forming a partially laminated Air is ejected from the cooling air hole 17.18 and cools the area after the hole 17.18.

The other air flows through the dorsal and ventral cold air ducts 13, 14, flows through the trailing edge 19 while cooling it, and flows out through the air exhaust hole 20 provided at the trailing edge end while cooling. Note that the shape of the rear edge portion may be such that a pin fin or the like may be used for cooling.

In this way, the cooling channels are installed separately in the front part and the rear part.

〔Effect of the invention〕

By separating the cooling flow paths into the front and rear parts, it is possible to suppress the temperature rise of the cooling air flowing through the cold air duct, and by using stratified cooling, as a result, a small amount of cooling air can be can be used efficiently and achieve sufficient cooling for all ranges.

Providing ribs on the outer sheath also significantly improves the mechanical strength of the outer sheath. It also has the effect of improving the output efficiency of the turbine.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an internal structure of an embodiment of a blade according to the present invention, and FIG. 2 is a cross-sectional view showing a conventional internal structure. 1...Outer cover, 2...Rib 3.4...
・Insert body, 6.7.13.14...Cold air duct 8, 9.17.18...Layered cooling air hole 10, I
s, 16...air hole, 19...rear edge part 20...
・Air vent representative Patent attorney Nori Chika Sokuma Kikuo Takehana '1111 illustration

Claims (2)

[Claims] (1) having a jacket and at least one insert, the insert touching chord-like projections on an inner wall of the jacket, between which a cold air duct is arranged; In a gas turbine blade having a perforation formed at the tip of the insert and cooling the inner surface of the tip of the outer cover through a turbulent flow chamber between the outer cover and the insert, the insert At least two insert bodies are provided, one of which has laminar cooling air that passes from the air hole at the tip through the turbulence chamber and into the cold air duct, and communicates with the cold air duct on the side wall surface of the jacket. In other inserts, air holes communicating with the cold air duct are provided in the side wall surface of the insert, and the cooling passage is provided with a cooling passage having a hole therein. A blade for a gas turbine, characterized in that the blade is provided with separate cooling passages by providing a cooling passage in which laminar cooling air holes communicating with the cold air duct are formed on the side wall surface of the blade. (2) The gas turbine blade according to claim 1, characterized in that a pin fin is provided at the rear edge of the outer cover.