JPH0658527A - Cooling structure for burner - Google Patents

Abstract

PURPOSE:To form a burner which provides an excellent cooling performance in simple assembling structure based on sheeting. CONSTITUTION:A plurality of cylinder-shaped inner wall materials 10a to 10c are continuously installed at a specified span in such a fashion that their front ends may face the inner side while their rear ends may be hidden outside the front ends of an adjacent inner wall material. As for each of cylinder-shaped outer wall materials 20a and 20b having a hole 30, their rear ends are fixed with the outside surfaces of the inner wall materials while the front ends and rear ends of the adjacent outer wall materials 20a and 20b are fixed. Cooling air enters from the hole 30 and cools the inner wall materials 10a to 10c and penetrates inside from between the inner wall materials 10a to 10c, thereby forming an air layer between combustion gas and the inner wall materials and further cooling the inner wall materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine such as a gas turbine or a jet engine, or a combustor cooling structure which is also a constituent element of a boiler.

[0002]

2. Description of the Related Art In order to avoid thermal deformation, oxidation or corrosion of the inner wall surface of a combustor due to high temperature combustion gas, a structure in which the wall surface is cooled by combustion air is generally adopted. . Conventionally, from the viewpoint of cooling performance and manufacturing cost, a film cooling structure manufactured by sheet metal molding as shown in FIG. 3 has been generally used.

In the film cooling structure, a part of the wall surface as shown in FIG. 3 is a double plate, and cooling air is introduced from a plurality of small holes opened in the double part, This is a structure for cooling the inner wall surface by forming a film of air, that is, a film, between the combustion gas and the inner wall surface.

However, recently, the temperature of the combustion gas tends to increase for the purpose of improving the performance of the engine, and accordingly, the cooling structure of the inner wall surface of the combustor is required to have a better cooling performance. It's coming. Further, from the viewpoint of environmental protection, it is socially required to reduce NOx in combustion exhaust, and therefore, cooling air for a combustor is reduced and the air is supplied to a combustion process. Is needed.

In response to such requirements, an impingement + film cooling structure as shown in FIG. 4 and a laminated structure as shown in FIG. 5 have been developed. The impingement + film cooling structure is a structure in which the impingement cooling structure and the film cooling structure are combined. Further, the impingement cooling structure is a in FIG.
This is a double plate structure, which is a structure for cooling the inner plate by blowing cooling air to the inner plate through a plurality of small holes formed in the outer plate. The portion b in FIG. 4 corresponds to the film cooling structure, and the structure and operation of this portion are the same as those shown in FIG.

In the laminated structure of FIG. 5, two plates are joined together,
Grooves are formed in the joint surface as passages for cooling air. Therefore, the cooling air flows from the large number of small holes formed in the outer plate to the groove portion of the joint surface, and then flows into the inner side, that is, the combustion gas side, from the small holes formed in the inner plate.

[0007]

According to the impingement + film cooling structure shown in FIG. 4, since the inner wall is particularly complicated, expensive machine tools such as forging, NC turning, laser processing, welding, etc. However, there is a problem in that the manufacturing cost becomes high because it has to be used for many steps.

Further, in the laminated structure shown in FIG. 5, there is a problem that the manufacturing cost becomes high because it is difficult to bond and groove the bonding surface.

It is an object of the present invention to provide a combustor cooling structure which is inexpensive to manufacture and has excellent cooling performance.

According to the cooling structure of the combustor according to the present invention,
A cooling structure for a combustor assembled from a plurality of tubular inner wall members and a plurality of tubular outer wall members having holes formed therein, so that the tip side faces the inside of the combustor in the direction of flow of combustion gas. The front end side and the rear end side of the adjacent inner wall members are overlapped with each other at a predetermined interval and are combined, and the rear end side of each outer wall member is fixed to the outer surface of each inner wall member and the front end side and the rear side of the adjacent outer wall member are fixed. The feature is that the ends are fixed to each other.

[0011]

The cooling air is blown into the inside from the hole of the outer wall member to cool the inner wall member from the outside. Then, the cooling air is blown into the inside through the gap between the adjacent inner wall members, and forms an air film between the combustion gas and the inner surface of the inner wall member.

[0012]

FIG. 2 shows a gas turbine to which a combustor cooling structure of the present invention is applied. In this gas turbine, the air entering from the intake plenum 1 is supplied to the first stage compressor 2 and the second stage compressor 2.
It is compressed by the stage compressor 3 and sent to the combustor 4. This air rises along the outer surface of the substantially cylindrical combustor 4 and enters the inside of the combustor 4 through a plurality of holes 5 provided above. Then, the fuel from the fuel injection valve 6 is mixed with this air and ignited by the spark plug 7. The combustion gas flows downward in the figure and is discharged after rotating the turbine 8.

FIG. 1 is a sectional view of a wall portion of the combustor 4 and shows a cooling structure thereof. The wall portion of the combustor 4 mainly includes a plurality of cylindrical inner wall members 10 (10a, 10a).
b), and a plurality of tubular outer wall members 20 (20a, 20b, ...) In each of which a plurality of holes 30 are formed.

Each inner wall member 10 has a tip end side (lower end side).
Is formed in a taper shape having a smaller diameter than the rear end side (upper end side), the front end side is the inner side, and the rear end side of the adjacent inner wall member 10 is the front end side with respect to the flow direction of the combustion gas indicated by the arrow in the figure. It is combined with a gap of a certain size so that it can be hidden outside.

The rear end side (upper end side) of each outer wall member 20 is fixed to the outer surface of the inner wall member 10 on the front end side,
The tip end side (lower end side) is fixed to the tip end side of the adjacent outer wall member 20, and a space 40 is formed between the inner wall member 10 and each inner wall member 10 with a predetermined gap.

Next, a method of manufacturing the wall portion of the combustor 4 will be described. First, the inner wall member 10 and the outer wall member 20 are formed by spinning a metal plate having a uniform plate thickness. next,
The front end portion of each inner wall member 10 and the rear end portion of the outer wall member 20 which should be adjacent thereto are welded and joined. In FIG. 1, the inner wall member 10a and the outer wall member 20a are welded, and the inner wall member 10b is welded.
And the outer wall member 20b are separately welded.

Next, the welded inner wall member 10 and outer wall member 2 are welded.
The combination of 0 is connected to another adjacent set, and the outer wall members 20 are welded to each other. In FIG. 1, the inner wall member 10b and the outer wall member 20b are inserted inside the outer wall member 20a, and the front end side of the outer wall member 20a and the rear end side of the outer wall member 20b are welded.

Therefore, in order to obtain the above-mentioned assembled structure, as shown in FIG. 1, the inner diameter φ of an outer wall member 20a is set.
A is larger than the outer diameter φB of the inner wall member 10c downstream of the outer wall member 20a in the flow direction of the combustion gas.

According to the structure of the combustor 4 as described above,
The cooling air flowing outside the combustor 4 flows into the space 40 defined by the inner wall member 10 and the outer wall member 20 from the hole 30 of the outer wall member 20, and cools the inner wall member 10 heated by the combustion gas.

Next, the air in the space 40 flows into the combustor 4 through the gap between the adjacent inner wall members 10, 10 along the flow direction of the combustion gas, and between the inner surface of the inner wall member 10 and the combustion gas. Form a film of air. Thereby, the inner wall member 10 is further cooled.

[0021]

According to the present invention, it can be manufactured by the same spinning and punching process of sheet metal as the conventional film cooling structure shown in FIG. 3, and the manufacturing cost can be kept low. And, even though the manufacturing cost is as low as that of the conventional film cooling structure, the cooling performance is about 3 times less than that of the conventional film cooling structure.
It is reduced by 0%. That is, according to the present invention, by adopting the assembly structure using the sheet metal, the cooling structure of the combustor having the excellent cooling performance at the low cost, which has not been achieved in the past, can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of a gas turbine to which an embodiment of the present invention is applied.

FIG. 3 is a cross-sectional view showing a conventional film cooling structure.

FIG. 4 is a cross-sectional view showing a conventional impingement film cooling structure.

FIG. 5 is a partially cutaway perspective view showing a conventional laminated structure.

[Explanation of symbols]

 4 Combustor 10 Inner wall member 20 Outer wall member 30 Hole

Claims (1)

[Claims] 1. A cooling structure of a combustor assembled from a plurality of cylindrical inner wall members and a plurality of cylindrical outer wall members having holes formed therein, wherein a tip end side of the combustor is in a flow direction of combustion gas. The front end side and the rear end side of the adjacent inner wall members are overlapped with each other at a predetermined interval so as to face the inside, and the rear end side of each outer wall member is fixed to the outer surface of each inner wall member and the adjacent outer wall member The cooling structure of the combustor, characterized in that the front end side and the rear end side of the are fixed to each other.