CN110296440B

CN110296440B - Gas turbine and method for improving the same

Info

Publication number: CN110296440B
Application number: CN201910221387.6A
Authority: CN
Inventors: M.R.波希恩; G.坎帕; A.斯卡帕托
Original assignee: Ansaldo Energia Switzerland AG; Ansaldo Energia SpA
Current assignee: Ansaldo Energia Switzerland AG; Ansaldo Energia SpA
Priority date: 2018-03-23
Filing date: 2019-03-22
Publication date: 2022-07-08
Anticipated expiration: 2039-03-22
Also published as: EP3543610A1; RU2019108054A; EP3543610B1; CN110296440A

Abstract

The invention relates to a gas turbine and a method for improving the same. Specifically, a gas turbine (1) has: a compressor (2); a pressure chamber (5) connected to the compressor (2); a combustion chamber (3) with a burner (7), which burner (7) has a front plate (8) and a burner (9) connected to the front plate (8). The front plate (8) and the burner (9) are at least partially accommodated in the plenum (5). The gas turbine comprises a damper (10) connected to the front plate (8) and accommodated in the plenum (5). The damper (10) has a chamber (11) tailored to the space available between adjacent burners (9). The present disclosure also relates to a method for improving a gas turbine.

Description

Gas turbine and method for improving the same

Cross Reference to Related Applications

This application claims priority from european patent application No. 18425016.5 filed on 23.3.2018, the disclosure of which is incorporated by reference.

Technical Field

The present invention relates to a gas turbine and a method for improving the same.

Background

Known gas turbines comprise: a compressor; a combustion chamber supplied with compressed air supplied from the compressor and fuel, the fuel being burned in the combustion chamber to generate hot gas of high pressure and high temperature; and a turbine where the hot gases are expanded to obtain mechanical work.

In particular, a compressor is connected to the plenum, and the combustion chamber has a combustor with a front plate, which is provided with a burner. The front plate and the burner are accommodated in a plenum such that compressed air is supplied into the plenum and from there it enters the burner where it is mixed with fuel and thus passed into the combustor, where combustion takes place.

The combustion process can result in pulsations that should be controlled and suppressed when they occur to prevent mechanical failure of the components of the combustion chamber.

One type of damper commonly used in gas turbine applications is the so-called Helmholtz (Helmholtz) damper; the helmholtz damper has a chamber connected via a neck to an environment in which pulsations to be damped are generated (such as a burner of a combustion chamber).

The frequency at which the pulsations are suppressed depends on the volume of the chamber and the length of the neck (in practice an effective length longer than the geometric length), so that in order to suppress pulsations in the relevant frequency range (for example between 50-500 Hz) a given ratio between the chamber volume and the neck length is required.

In addition, the efficiency of the helmholtz damper depends on the volume of the chamber, so that the larger the volume, the higher the damping effect.

Other kinds of dampers are known, such as half-wavelength or quarter-wavelength dampers; these dampers have similar constraints with respect to geometrical proportions and volume as helmholtz dampers. In the following description, reference is made to a helmholtz damper.

To optimize the damping effect, the damper should be provided at a region of the burner close to the region where the flame is anchored during operation, since pulsations are generated there.

However, because of the constraints imposed by the required geometric proportions of the damper, the volume of the chamber and the very small space available in the region of the burner, it may be difficult or even impossible to provide the damper with the required characteristics and at the required location.

Disclosure of Invention

Aspects of the present invention include providing a gas turbine with a damper that is capable of effectively damping pulsations in a desired frequency range while being positioned at a desired location of the combustor proximate to a region where the flame is anchored.

Another aspect of the invention includes providing a method for retrofitting a gas turbine.

These and further aspects are obtained by providing a gas turbine and a method according to the appended claims.

Drawings

Further characteristics and advantages will be more apparent from the description of preferred, but not exclusive, embodiments of the gas turbine and of the method, illustrated by way of non-limiting example in the accompanying drawings, in which:

FIG. 1 schematically illustrates a gas turbine;

FIG. 2 illustrates a portion of a combustor of a gas turbine without a damper;

FIG. 3 illustrates a portion of a combustor of a gas turbine with a damper;

fig. 4 to 7 show different examples of front plates with burners and dampers;

fig. 8 to 10 show an enlarged portion of the front plate and the area surrounding it in different embodiments;

fig. 11 to 12 show different examples of dampers;

figure 13 shows a damper attached to a front plate.

Reference numerals

1 gas turbine

2 compressor

3 combustion chamber

4 turbine

5 pressure chamber

7 burner

8 front panel

9 burner

10 damper

11 chamber

13 outer periphery

15 inner periphery of

Wall of 16 pressure chambers

17 neck part

18 first opening

20 guide member

21 flame

23 terminal portion

25 second opening

26 gap

28 vortex flow

F1 first air flow

F2 second air flow

The size of the S damper.

Detailed Description

Referring to the drawings, there is shown a gas turbine 1 having a compressor 2, a combustor 3 and a turbine 4. The gas turbine also has a plenum 5 connected to the compressor 2; the front end of the combustion chamber 3 is accommodated in the pressure chamber 5. The combustion chamber 3 comprises a burner 7 with a front plate 8 and a burner 9 connected to the front plate 8. The burner 9 is connected to a fuel supply system (not shown) for fuel supply.

The gas turbine 1 comprises one or preferably more than one damper 10 connected to the front plate 8 and accommodated in the plenum 5. In this way, the damper is connected to the region of the combustion chamber close to the region where the flame is anchored, the combustion process takes place and pulsations may be generated. The suppression in this region prevents the pulsation from propagating through the burner and possibly damaging it.

In a preferred embodiment, the combustion chamber 3 is an annular combustion chamber and the burners 9 are provided over the entire circumference of the combustion chamber. Preferably, the circumferential distance between the burners is constant, but it may also be different in certain applications. Preferably, all burners are placed on one circumference (fig. 4-6, 11, 12), but embodiments with burners placed on different circumferences, such as concentric circumferences, are also possible (fig. 7).

The damper 10 has a chamber 11, which chamber 11 is tailored to the space available between adjacent burners 9. This feature allows for an optimized use of the available space, so that the volume of the chamber 11 and hence the efficiency can be optimized (e.g. maximized).

Preferably, the customization is performed in the plane of the front plate 8 according to the space available between adjacent dampers 10, as shown for example in fig. 4 to 7.

The customization comprises shaping the chamber 11 (fig. 4-7) in the plane of the front plate 8 to fit the chamber shape to the available space between the burners 9.

Preferably, to further optimize the use of available space, the chamber 11 is further customized to the outer perimeter 13 of the front plate 8.

The customization comprises shaping the chamber 11 in the plane of the front plane 8 (fig. 4 to 7) for adapting the chamber shape to the available space delimited by the outer perimeter 13.

For example, a substantially triangular space may be defined between the outer periphery 13 of the front plate 8 and the adjacent burner 9, and the chamber 11 preferably has a substantially triangular shape and is accommodated in this space (fig. 4).

Additionally or alternatively, the front plate 8 may be annular in shape, and the chamber 11 may be further customized to the inner periphery 15 of the front plate 8.

The customization comprises shaping the chamber 11 in the plane of the front plane 8 (fig. 5 to 7) for adapting the chamber shape to the available space delimited by the inner perimeter 15.

For example, a substantially triangular space may be defined between the inner periphery 15 of the front plate 8 and the adjacent burner 9, and the chamber 11 has a substantially triangular shape and is accommodated in this space (fig. 5).

In further examples, the chamber 11 may extend between the inner perimeter 15 and the outer perimeter 13 of the annular front plate 8. In this case, the use of the available space is further optimized (fig. 6).

In addition, to optimize even further the use of the available space, the chamber 11 can be customized according to the walls 16 delimiting the plenum 5 (fig. 9, 10).

Damper 10 is preferably a helmholtz damper and includes a chamber 11 and a neck 17 connected between chamber 11 and front plate 8. Nevertheless, other kinds of dampers (half-wavelength or quarter-wavelength or other) as described above are possible.

In a preferred and advantageous embodiment, the damper 10 does not substantially affect the air flow through the burners 9, and therefore does not substantially affect the total flow through all the burners 9, nor the flow through each burner 9. For example, this feature may facilitate retrofitting of existing gas turbines; this feature may also be useful in new gas turbines, for example, leaving the possibility of upgrading or to allow existing data regarding combustion and/or formation of air/fuel mixtures and/or air flow through dampers to be used during design.

Referring to fig. 2 and 3, during operation, when no damper 10 is provided connected to the front plate 8, a first air flow F1 passes through the burner 9, and when the damper 10 (one or more dampers) is connected to the front plate 8, a second air flow F2 passes through the burner 9.

The chamber 11 has a given dimension S in a direction away from the front plate 8. Advantageously, the given dimension S is limited such that the second air flow F2 is substantially the same as the first air flow F1.

The fact that the restricted dimension S is restricted does not mean that it is smaller than or equal to the distance between the first opening 18 for air to enter the burner 9 and the front plate 8; the given dimension S may be smaller than or equal to or even larger than the distance between the first opening 18 for air to enter the burner 9 and the front plate 8, as long as the air flow into the burner 9 is substantially not obstructed.

In addition, in a particularly advantageous embodiment, the mass flow distribution through the burners and for each burner is substantially unaffected, i.e. it is substantially unchanged, whether or not a damper is provided.

In this connection, the gas turbine may be provided with a guide 20, which guide 20 influences the air flow F2 such that the distribution of the air flow F2 is substantially the same as the distribution of the air flow F1. The guide 20 may be defined by the shape of the chamber 11 (fig. 9, 12) and/or the neck 17; alternatively or additionally, the guide may also be defined by a baffle or a deflector member (fig. 10, 11) provided within the pressure chamber 5, for example connected to the chamber 11 and/or the neck 17 and/or not connected to the chamber 11 or the neck 17 as a separate element.

The operation of the gas turbine is apparent from that described and illustrated and is substantially as follows.

The compressor 2 compresses air and supplies it into the pressure chamber 5. From the plenum 5, a flow F2 of compressed air enters the burner 9 via the first opening 18, it is mixed with fuel and the mixture is fed into the combustor 7. In the combustor 7, the mixture is burned to generate hot gas, which is expanded in the turbine 4.

The pulsation generated into the combustor 7 is suppressed by the damper 10. The damping is effective because, due to the optimization of the use of available space, the damper can be designed such that the frequency range to be damped and the damping efficiency match the requirements.

The invention also relates to a method for improving a gas turbine.

In particular, the method comprises providing at least one damper 10 connected to the front plate 8 and housed in the plenum 5, the damper 10 having a shape tailored to the space available between adjacent burners 9.

In a preferred embodiment of the method, the damper 10 has a given dimension S away from the front plate 8, and the method comprises limiting the given dimension S such that the provision of the damper 10 does not affect the air flow through the burner 9, e.g. does not substantially result in a reduction of the air flow through the burner 9.

Fig. 13 shows the arrangement of the damper 10 (as previously described or also of a different type) connected to the front plate 8.

This arrangement is useful (but not mandatory) when the damper 10 must be attached close to the location of the flame anchor (e.g., the attachment may be made to the front plate 8 or elsewhere).

FIG. 13 shows a Helmholtz damper having a neck 17 connected to front plate 8 and chamber 11; the figure also shows a burner 9 and a flame 21 generated by fuel supplied via the burner 9; the flame may be a premixed flame or a diffusion flame.

The damper 10 has its terminal portion 23 inserted in a second opening 25 of the front plate 8. Specifically, a gap 26 (e.g., an annular gap) is defined between the second opening 25 and the terminal portion 23. The terminal portion 23 of the damper 10 facing the front plate 8 is flared.

The gap 26 and flared terminal portion 23 are advantageous because they provide an efficient way of cooling the terminal portion 23. In fact, the gap 26 allows an air flow to pass through it; such air flow cools the terminal portion 23 of the damper 10.

In addition, because the gap 26 constitutes a restricted nozzle for air flow (e.g., because of the flared terminal portion 23), the air flow is accelerated as it passes through the gap 26, further improving cooling efficiency.

In addition, although cooled, it does not affect the operation of the damper 10 and therefore its damping efficiency. In practice, the flared terminal portion 23 defines a diverging nozzle, which projects a flow of air away from the neck 17, for example, through a tapered path. The vortices 28 at the neck 17 (which inhibit vibrations) are therefore not affected and the efficiency of the inhibition is therefore not affected.

For example, when the damper 10 is in a position close to the flame 21, this arrangement advantageously allows cooling the neck 17 to prevent its damage without affecting its damping efficiency.

Of course, the described features may be provided independently of each other. For example, the features of each of the appended claims may be applied independently of the features of the other claims.

In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art.

Claims

1. A gas turbine (1) having: a compressor (2); a pressure chamber (5) connected to the compressor (2); -a combustion chamber (3) with a burner (7), said burner (7) having a front plate (8) and a burner (9) connected to said front plate (8), said front plate (8) and said burner (9) being at least partially housed in said plenum (5), characterized in that said gas turbine (1) comprises at least one damper (10) connected to said front plate (8) and housed in said plenum (5), said damper (10) having a chamber (11) customized according to the space available between adjacent burners (9);

wherein the damper (10) is a Helmholtz damper and comprises the chamber (11) and a neck (17), the neck (17) being connected between the chamber (11) and the front plate (8).

2. Gas turbine (1) according to claim 1, wherein the chamber (11) of the damper (10) is further customized according to the outer periphery (13) of the front plate (8).

3. A gas turbine (1) according to claim 2, wherein a substantially triangular space is defined between the outer periphery (13) of the front plate (8) and the adjacent burner (9), the chamber (11) having a substantially triangular shape and being accommodated in this space.

4. A gas turbine (1) according to claim 2 or claim 3, wherein the front plate (8) is annular in shape and the chamber (11) is further customized according to an inner periphery (15) of the front plate (8).

5. A gas turbine (1) according to claim 4, wherein a substantially triangular space is defined between the inner periphery (15) of the front plate (8) and the adjacent burner (9), the chamber (11) having a substantially triangular shape and being accommodated in this space.

6. Gas turbine (1) according to claim 4, wherein said chamber (11) extends between said inner periphery (15) and said outer periphery (13) of said annular front plate (8).

7. Gas turbine (1) according to any of claims 1 to 3, wherein said chamber (11) is customized according to the walls delimiting said plenum (5).

8. Gas turbine (1) according to any of claims 1 to 3, characterized in that during operation,

when no damper (10) is provided connected to the front plate (8), a first air flow (F1) passes through the burner (9), and

a second air flow (F2) through the burner (9) when the damper (10) is arranged connected to the front plate (8),

wherein

The chamber (11) has a given dimension (S) in a direction away from the front plate (8), and

the given dimension (S) is limited such that the second air flow (F2) is substantially the same as the first air flow (F1).

9. Gas turbine (1) according to any of claims 1 to 3, characterized in that during operation,

a second air flow (F2) through the burner (9) when the damper (10) is arranged to be connected to the front plate (8),

characterized in that the gas turbine (1) is provided with at least one guide which influences the second air flow (F2) such that the distribution of the second air flow (F2) is substantially the same as the distribution of the first air flow (F1).

10. Gas turbine (1) according to claim 9, characterized in that said at least one guide is defined by the shape of said chamber (11) and/or neck (17) and/or by at least one baffle or deflector member provided within said plenum (5).

11. Gas turbine (1) according to any of claims 1 to 3,

the damper (10) having a terminal portion (23) facing the front plate (8),

the front plate (8) has a second opening (25),

said terminal portion (23) being flared,

the terminal portion (23) is inserted into the second opening (25),

a gap (26) is defined between the terminal portion (23) and the second opening (25),

the gap (26) defines a diverging nozzle for ejecting an air flow away from the damper (10).

12. A gas turbine (1) according to claim 11, wherein said gap (26) defines a restricted nozzle which accelerates said air flow through it.

13. Method for improving a gas turbine (1), the gas turbine (1) having a combustion chamber (3) with a front plate (8), a plenum (5) facing the front plate (8), a burner (9) accommodated in the plenum (5) and connected to the front plate (8),

the method is characterized by providing at least one damper (10) connected to the front plate (8) and housed in the plenum (5), the damper (10) having a chamber (11) tailored to the space available between adjacent burners (9);

14. The method of claim 13, wherein,

the damper (10) having a given dimension (S) away from the front plate (8),

the method is characterized in that the given size (S) of the damper (10) is limited such that the provision of the damper (10) does not affect the air flow through the burner (9).