JPH0617652B2 - Gas turbine combustor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas turbine combustor, and more particularly to a gas turbine combustor that effectively cools a combustor liner and a transition piece exposed to high-temperature combustion gas. .

[Conventional technology]

As a conventional cooling device for a transition piece of a gas turbine combustor, a collision plate having a large number of small holes is provided on the outer periphery of the transition piece to perform so-called collision cooling, as described in JP-A-62-9157. Are known.

[Problems to be Solved by the Invention]

In this conventional apparatus, the cooling air that has collided with the outer surface of the transition piece from the collision plate cools the transition piece and flows toward the combustor liner side to convectively cool the outer surface of the liner.
It is generally known that impact cooling has a higher cooling effect than convection cooling, so that the conventional device has a sufficient cooling effect on the transition piece, but the combustor liner cannot be cooled sufficiently. Occurs. Further, since the entire amount of cooling air that has collided with the surface of the transition piece flows toward the head of the combustor, the collision cooling flow interferes due to the air flow along the wall surface as it approaches the liner side, and the effect of collision cooling is sufficient. Can not be demonstrated to.
Further, in the collision cooling, the cooling air needs to collide with the cooling surface at a high speed, so that the pressure loss tends to increase,
Therefore, there is also a problem that the entire amount of compressed air taken into the outer cylinder cannot be used for collision cooling, and as seen in the conventional example, a part of the compressed air taken into the outer cylinder is used for collision cooling and the rest is The method used to cool the liner is used.

This method divides the collision cooling air amount and the convection cooling air amount of the liner so as to satisfy the required cooling amount of the liner and the transition piece when the amount of compressed air supplied to the outer cylinder is constant. The ratio can be determined, but, for example, when coal gasification fuel is used, the amount of air required for combustion changes, so the amount of air taken into the outer cylinder changes and cooling is partially incomplete. There is a problem that will be sufficient.

An object of the present invention is to provide a compressed air supplied to an outer cylinder with a liner,
It is to provide a gas turbine combustor and a cooling method that can be effectively used for cooling a transition piece. Therefore, even if the operating condition is such that the compressed air compressed in the outer cylinder is reduced, a desired cooling effect can be obtained. It is to provide a gas turbine combustor in which

[Means for Solving the Problems]

The above object is achieved by using the compressed air supplied to the outer cylinder to cool the transition piece and then repeatedly to cool the liner. Moreover, even if a large amount of compressed air is used as the cooling air, a cooling system is adopted in which the cooling action is less deteriorated and the pressure loss generated in the flow path of the cooling air is not as large as possible.

That is, it is achieved by using almost all of the compressed air taken into the outer cylinder as a cooling flow for convectively cooling the outer circumference of the transition piece, and using the air used for convective cooling as collision cooling air on the outer surface of the liner. .

In particular, the gas turbine combustor of the present invention has a combustor liner having a combustion nozzle at its head to form a combustion chamber, a transition pipe for guiding combustion gas generated in the combustion chamber to a gas turbine blade, a liner and transition pipe. And a convection cooling cylinder that is formed along the outer periphery of the transition piece and that guides the cooling air substantially in the axial direction of the transition piece, the collision between the liner and the extension tube. It is characterized by having a cooling cylinder. This collision cooling cylinder
A large number of small holes are provided for causing the cooling air that has passed through the convection cooling cylinder to collide with the outer peripheral surface of the liner in a substantially radial direction.

Further, the compressed air taken into the outer cylinder entirely flows along the outer circumference of the transition piece, and collides with the outer peripheral surface of the liner through the small holes formed in the collision cooling cylinder.

Further, the liner and the collision cooling cylinder are formed in a concentric cylindrical shape, and the tail cylinder side ends are both connected to the tail cylinder.

[Action]

According to the configuration of the present invention, the compressed air taken into the outer cylinder first flows on the outer surface of the transition piece to cool the transition piece, but this convection cooling is different from collision cooling even if the air flow is large, The cooling efficiency does not decrease, and the pressure loss is reduced by increasing the flow passage area. Next, the liner
Although it will be cooled by the collision air, the liner has many secondary air intakes for combustion, so when collision air collides with the liner wall, it immediately enters the combustion chamber through the air intake and collides. Since an air flow that interferes with the air flow is unlikely to occur, the effect of collision cooling is sufficiently exerted.

〔Example〕

Examples of the present invention will be described below. FIG. 1 shows the main components of a gas turbine. In this example, a plurality of combustors are annularly arranged upstream of the turbine. Reference numeral 1 is a compressor outer cylinder, 2 is a compressor rotor blade, 3 is a compressor stationary blade, 4 is a compressor diffuser, and 5 is compressor discharge air. Reference numeral 6 is a combustor outer cylinder, and 7 is a convection cooling cylinder that produces forced convection for cooling the combustor liner 8. Reference numeral 9 is a transition piece for guiding high temperature combustion gas to the turbine inlet, 10 is a gas fuel nozzle having an air swirl vane on the outer peripheral portion, and 11 is an oil nozzle used for starting the gas turbine and for low load. 12 is fuel gas, 13 is turbine first stage vane, 14 is turbine first
It is a stepping blade.

The high-pressure, high-speed air 5 discharged from the compressor 1 is decelerated by the diffuser 4, recovers the pressure, and is supplied to the combustor liner 8 while cooling the transition piece 9 on the way. The air 5 supplied to the combustor is a collision cooling cylinder 7 for cooling the combustor liner 8.
The flow velocity is increased as it passes through the holes formed in the cooling cylinder 7 and flows into the combustion chamber while collision cooling the combustor liner 8. The combustion gas 12 is guided to the gas turbine inlet 13 by the transition piece 9 and is discharged to the outside of the standby where the gas turbine has worked.

To start the gas turbine, first, the compressor 1 is rotated by external power, and when the rotational speed reaches about 20% of the rated rotational speed, preparation for ignition of the combustor is started.

To ignite the combustor, first, the ignition plug 15 is energized to blow the spark, and then the oil fuel is sprayed from the oil nozzle 11 to start combustion. When the flow rate of oil fuel is gradually increased and the compressor speed reaches the rated value, the load can be taken out from the turbine.

A low-calorie gas such as coal gasification gas or blast furnace gas obtained from a blast furnace has a small proportion of combustible components contained in its unit volume, and conversely contains 60 to 70% of inactive components. It is hard to burn in the state. Therefore, it becomes difficult to perform low-calorie single combustion in a fuel-lean region such as the low-load side of the gas turbine. Therefore, in the low load region of the turbine, operation is performed with high calorie gas or oil fuel. For this reason, even if the load can be taken out from the turbine after the number of revolutions of the compressor reaches the rated value, combustion of high-calorie fuel such as oil fuel is continued and the load is taken.

On the other hand, the low-calorie gas is switched to the high-calorie fuel when the turbine load is in that state because the mass ratio of fuel and air that enables the single combustion of the low-calorie gas is known in advance.

These things have many problems as mentioned before. That is, it is necessary to secure the same gas temperature and combustion gas flow rate when burning high-calorie fuel and when burning low-calorie fuel. Therefore, the mass ratio of fuel to air is approximately 2: 100 or 3: 100 in high-calorie combustion, while 1: 2 or 1: in low-calorie combustion.
It will be about 4. This means that in high-calorie combustion, the amount of air flowing in the cooling cylinder 7 is larger than that in low-calorie combustion.

FIG. 2 shows an embodiment of the present invention. The air 5 exiting the compressor diffuser 4 becomes a reverse flow 5 ′ and flows into the flow path 5 ″ for cooling the transition piece 9 to form a flow 5a, while flowing toward the inlet of the transition piece 9 The air 5b, which cools the transition piece 9 and has a slightly increased temperature, flows out from the flow path 5 ″ for cooling the transition piece 9 into the space formed by the collision cooling tube 7 and the combustor outer tube 6. Inflow. That is, this space is loosely partitioned from the flow path for cooling the combustor liner 8, and has a function of adjusting the air flow for liner cooling. This space is called the reservoir chamber 15. In order to prevent the air 5b flowing out from the flow passage 5 ″ for cooling the transition piece from directly flowing into the cooling tube 7 from the transition piece inlet direction toward the combustor upstream direction,
A partition ring 7b is provided. The partition ring 7b does not have to completely partition the cooling cylinder interior 7c and the space 15. In this case, a part of the discharge air 5b will flow from the rear of the combustor to 7c along the combustor.

The air once stored in the space 5c flows into the inside of the cooling cylinder 7c at high speed from the air ejection holes 7a formed in the cooling cylinder, and collides with the combustor liner 8. The air impinging on the combustor liner spreads along the outer surface of the combustor, and at this time, heat is taken from the combustor liner to lower the temperature of the combustor liner.
Part of the air that has flowed into the cooling cylinder flows into the combustion chamber as combustion air, and part of the air forms an air film while flowing along the inner wall of the combustor and flows into the combustion chamber.

FIG. 3 is a detailed view of a combustor liner and an impingement cooling cylinder in another embodiment. The place where collision cooling is applied is the head of the combustor liner, which tends to reach a relatively high temperature in the case of film cooling, and the downstream of the combustor line is an extension of the transition pipe cooling method. Partition 7b for cooling cylinder 7c and external space
Is loosely partitioned. The pitch of the air ejection holes 7a formed in the cooling cylinder is preferably dense at the head and coarse at the downstream so as to improve the temperature distribution of the liner 8.

FIG. 4 shows an example of the cooling effect in this embodiment. The fuel used was a gas with a calorific value of 930 kcal / Nm ³ , and the combustor outlet gas temperature was 1260 ° C. Air temperature is 330
° C, fuel temperature is 340 ° C. The symbol Δ in the figure shows the result of using the convection cooling method which is a conventional cooling method, and shows a metal temperature of 800 ° C. or higher in the range of the axial direction distance of the liner from 100 mm to 300 mm.

On the other hand, it can be seen that the mark ○ indicates the cooling method according to the present invention, which is 100 deg lower than that of the conventional cooling method.

〔The invention's effect〕

According to the present invention, it is possible to cool a high-calorie fuel and a low-calorie fuel with the same combustor cooling structure and with the same degree of pressure loss, thereby reducing the efficiency of the gas turbine. In addition, the combustor can be sufficiently cooled with a small amount of cooling air as in the case of burning low-calorie fuel.

In addition, the cooling structure does not change significantly from the conventional one, only the cooling cylinder needs to be changed, so the conventional reliability can be continued as it is.
It is also economically superior.

[Brief description of drawings]

FIG. 1 is a main configuration diagram of a gas turbine according to the present invention,
FIG. 2 is a detailed diagram of the combustor, FIG. 3 is a specific example of the combustor cooling cylinder, and FIG. 4 is a characteristic diagram showing an example of the effect of the embodiment. 6 ... Outer cylinder, 7 ... Collision / cooling cylinder, 7a ... Air ejection hole, 8 ...
Combustor liner, 9 ... Tail tube, 5 ″ ... Convection cooling passage.

Continuation of the front page (56) Reference JP-A-55-10004 (JP, A) JP-A-58-72822 (JP, A) JP-A-62-9157 (JP, A) JP-A-59-56618 (JP , A) JP 62-197645 (JP, A) Actually opened 63-71432 (JP, U) Actually opened 63-71434 (JP, U) Actually published 63-25317 (JP, Y2)

Claims (3)

[Claims] 1. A combustor liner having a combustion nozzle at its head to form a combustion chamber, a tail pipe for guiding combustion gas generated in the combustion chamber to a gas turbine blade, and an outer portion surrounding the liner and the tail pipe. A gas turbine combustor comprising a cylinder and a convection cooling cylinder that is formed along the outer periphery of the transition piece and guides cooling air substantially in the axial direction of the transition piece, between the liner and the outer tube. There is a collision cooling cylinder, the collision cooling cylinder, the cooling air that has passed through the convection cooling cylinder,
A gas turbine combustor comprising a large number of small holes for substantially radially colliding with the outer peripheral surface of the liner. 2. The compressed air taken into the outer cylinder as set forth in claim 1, flows entirely along the outer periphery of the transition piece, and passes through the small holes formed in the collision cooling cylinder. A gas turbine combustor characterized by colliding with an outer peripheral surface of the liner. 3. The liner and the impingement cooling cylinder according to claim 1, wherein the liner and the collision cooling cylinder are formed in a concentric cylindrical shape, and both ends of the transition piece are connected to the transition piece. Gas turbine combustor.