WO2011134713A1

WO2011134713A1 - Burner system and method for damping such a burner system

Info

Publication number: WO2011134713A1
Application number: PCT/EP2011/053880
Authority: WO
Inventors: Sven Bethke; Michael Huth
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-04-28
Filing date: 2011-03-15
Publication date: 2011-11-03
Also published as: EP2383514A1

Abstract

The invention relates to a burner system comprising at least two adjacent burners (7), each of which has at least one combustion chamber (6) and a head end (51), wherein the latter comprises at least a fuel injection (55) and a fuel-air premix (56), wherein the burner (7) has a plenum (100) upstream of the fuel-air premix (56), wherein the plenum (100) is bounded by a plenum wall comprising a plenum upper wall (170) and a plenum side wall (150), facing in the direction of flow, wherein the plenum upper wall (170) is arranged ahead of the head end (51), seen in the direction of flow, wherein the plenum side wall (150) is arranged at least partially ahead of the head end (51), seen in the direction of flow, wherein the plenum wall has a side (140) facing the plenum and a side (120) facing away from the plenum and wherein the plenum wall has on the side (120) thereof that is facing away from the plenum at least one resonator. The invention also relates to a method for damping such a burner system.

Description

description

Burner system for damping a burner system

The invention relates to a burner system with at least two adjacent burners, each of which at least one

Combustion chamber and a head end, the latter comprising at least one fuel injection and a fuel-air premix, the burner having a plenum upstream of the fuel-air premix, the plenum being bounded by a plenum wall having a plenum top wall and a plenum side wall facing in the flow direction, wherein the plenum top wall is arranged upstream of the head end, viewed in the flow direction, wherein the

Plenumsseitenwand is at least partially disposed in the flow direction in front of the head end, wherein the

Plenum wall has a side facing the plenary and a side facing away from the plenary.

A gas turbine plant comprises in the simplest case

Compressor, a combustion chamber and a turbine. in the

Compressor takes place a compression of sucked air, which is then admixed with a fuel. In the combustion chamber, a combustion of the mixture takes place, wherein the combustion exhaust gases are supplied to the turbine, deprived of the combustion exhaust energy and into mechanical

Energy is implemented.

Fluctuations in fuel quality and others

However, thermal or acoustic disturbances lead to it

Fluctuations in the amount of heat released. There is an interaction of acoustic and thermal disturbances, which can oscillate. Such thermoacoustic oscillations in the combustion chambers of gas turbines - or turbomachines in general - pose a problem in the design and operation of new combustors, combustor parts and burners for such

Turbomachines. To reduce pollutant emissions, is used in modern

Systems of cooling mass flow reduced. This also reduces the acoustic damping, so that thermoacoustic vibrations can increase. This can lead to a aufschaukelnden interaction between thermal and acoustic disturbances, the high loads of

Combustion chamber and rising emissions. These thermoacoustically induced instabilities are significantly influenced by the acoustic properties of the combustion chamber and the boundary conditions present at the combustion chamber ^inlet and combustion chamber ^exit and at the combustion chamber walls. To reduce thermoacoustic

Vibrations are therefore made in the prior art e.g.

Helmholtz resonators used for damping, the

Dampening the amplitude of vibrations of certain frequencies. A Helmholtz resonator typically includes a volume of air or other gas therein. To the

Volume is followed by a neck, the so-called. Resonatorhals, in which also air or gas is located and which opens into the combustion chamber. The air or the gas in the volume and the resonator neck form a spring-mass system, wherein the air or the gas in the volume of the spring and the air or the gas in the resonator neck forms the mass. When the spring-mass system oscillates at a resonant frequency determined by the volume, the cross-sectional area of the resonator neck, and the length of the resonator neck, the Helmholtz resonator behaves like an infinite-length aperture which prevents a standing wave from interfering with itself of the

Resonant frequency can form.

WO 93/10401 AI shows a device for suppressing combustion oscillations in a combustion chamber of a gas turbine plant. A Helmholtz resonator is fluidically connected to a fuel supply line. The acoustic properties of the supply line or the overall acoustic system are thereby changed so that be suppressed vibration. However, it has been shown that this measure is not sufficient in all operating conditions, as it can lead to combustion oscillations even with a suppression of vibrations in the fuel line.

WO 03 / 074936A1 shows a gas turbine, with a burner, which opens into a combustion chamber, said mouth

is surrounded annularly by a Helmholtz resonator.

As a result, combustion vibrations are effectively attenuated by close contact with the flame, at the same time

Temperature irregularities are avoided. By doing

Helmholz resonator tubes are attached, which cause a frequency adjustment.

EP 0 597 138 A1 describes a gas turbine combustion chamber which has air-purged Helmholtz resonators in the region of the burners. The resonators are arranged alternately on the end face of the combustion chamber between the burners. By these resonators, vibration energy is absorbed by combustion vibrations occurring in the combustion chamber and the combustion vibrations are thereby damped.

The object of the present invention is therefore to specify a burner system which is used to dampen

Combustion is used and which avoids the above problem.

For this purpose, a burner system has at least two adjacent ones

Burner, each of which has at least one combustion chamber and a head end, the latter at least one

Fuel injection and a fuel-air premix, wherein the burner upstream of the fuel-air premix has a plenum wherein the plenum through a plenum wall with a plenum top wall and an in

Flow direction facing plenum sidewall is limited, the plenum upper wall seen in the flow direction before is arranged at the head end, wherein the plenum side wall is at least partially disposed in the flow direction in front of the head end, wherein the plenum a the

Plenum facing side and a side facing away from the plenary.

It is known that the performance of gas turbines at

Use of tube combustion chambers by the occurrence of

thermoacoustic vibrations in these combustion chambers

is limited. These have so far been reduced with Helmholtz resonators. So far only Helmholtz resonators with a fixed resonance frequency have been used. These resonators were mounted on the combustion chamber outer wall to dampen or suppress the acoustic pressure fluctuations in the combustion chamber.

The resonant frequency of a real Helmholtz resonator is given approximately in accordance with the equation f c / (2π) (5 / (L * V)). Here, c is the speed of sound in the medium, V is the volume of the resonator chamber, L is the length and S is the area of the resonator neck between the resonator chamber and the surroundings. The volume V thus influences the resonant frequency of the resonator. The volume in the resonator chamber behaves like a spring and the fluid mass in the neck behaves like the mass of a mechanical spring-mass system. The resonator works in the ideal case as a absorber, by the am

Resonator neck start impressed pressure oscillation to a different frequency than that generated in the combustion chamber

shifts. In reality, influences like change

Fluid friction, etc. the effectiveness of the resonators clearly, so they do not sound as a sound absorber, but as a sound absorber act, but the sound amplitude only reduced, and can not be erased by far.

In addition, the essential excitation mechanism can not be interrupted by this arrangement. Pressure and sound velocity in the burner itself are not affected.

This is where the invention intervenes. According to the invention, the plenum wall has at least one resonator on its side facing away from the plenum. This is particularly advantageous over the prior art, in which the resonators are mounted directly on the combustion chamber or on the combustion chamber outer wall, since the pressure fluctuations already in plenary

be prevented or suppressed. Characterized eigenmodes of the combustion chamber are avoided or at least reduced.

By the invention, thermoacoustic vibrations are largely prevented or even avoided and also speed fluctuations in the field of

Fuel Injection / Fuel-Air Premix

prevented.

The installation of the resonator on the plenum wall gives the advantage over lower temperatures compared to the attachment to the combustion chamber. Furthermore, a realization is particularly easy to implement.

In a preferred embodiment, the resonator has a volume and a resonator neck, wherein only the

Resonator neck openings to the plenum. A

Flow through the resonators with cooling air is namely not necessary. This eliminates the cooling air holes on the

Rear of the resonators, which is the effectiveness of

Reduce resonators.

By means of detailed analyzes of the mode distribution in the

Combustion system was recognized that the Sound pressure distribution in the plenary upstream of the burner has a significant effect on the sound pressure in the combustion chamber. According to the invention, it has been recognized that by suppressing the pressure fluctuations in plenum, the formation of the typical eigenmodes of the combustion chamber can likewise be reduced or completely prevented. This is now by the attachment of a resonator on the plenumsabgewandten side of

Plenumswand achieved, thereby the pressure oscillation in the

Suppress plenum. In addition, moreover, too

Speed variations in the range of

Fuel Injection / Fuel-Air Premix

prevented.

Preferably, the plenum sidewall is at least partially disposed about the head end, and in that case the

Plenumsseitenwand is spaced in a radial direction from the head end. In a preferred embodiment, a channel is formed by the plenum side wall and the head end. Through this channel, compressor air becomes plenum

directed. This compressor air thus cools the outside of the combustion chamber and thus reduces overheating of the

Combustion chamber. Ideally, so will the compressor air

preheated, so that a more stable combustion can take place.

Preferably, the resonator is a Helmholtz resonator. In a preferred embodiment, the Helmholtz resonator on a neck which is adjustable in length. This can be realized for example via an adjustable sleeve. Thus, in the combustion chamber different

Frequencies are damped.

Preferably, a plurality of burners are provided, each one

Brenner a plenary with a plenary limiting

Plenum wall with at least one resonator on her

plenumsabgewandten side has. Thus, the

Vibrations are reduced throughout the gas turbine. Advantageously, a gas turbine comprises such

Burner system.

Further features, properties and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying figures.

Fig. 1 shows schematically a gas turbine in one

Partial longitudinal section,

2 shows a tube burner with plenum,

3 shows schematically the resonator according to the invention,

FIG. 1 shows by way of example a gas turbine 1 in a longitudinal partial section.

The gas turbine 1 has inside a rotatably about a rotation ^¬ axis 2 rotatably mounted rotor 3 with a shaft, which is also referred to as a turbine runner.

Along the rotor 3 follow one another a suction housing 4, a compressor 5, for example, a toroidal combustion chamber 6, with a plurality of coaxially arranged burners 7, a turbine 8 and the exhaust housing. 9

The combustion chamber 6 communicates with an example

Hot gas channel 11. There form, for example, four

The turbine 8 is connected in series with each turbine stage 12. Each turbine stage 12 is formed, for example, from two blade ^rings . As seen in the direction of flow of a working medium 13 follows in the hot gas channel 11 of a row of vanes 15 formed by a rotor blades 20 row 25. During operation of the gas turbine 1 4 air 35 is sucked and compressed by the compressor 5 through the intake housing. The at the turbine end of the compressor. 5

provided compressed air is the burners. 7 guided and mixed there with a fuel. The mixture is then burned to form the working medium 13 in the combustion chamber 6. From there, the working fluid 13 flows along the hot gas channel 11 past the guide vanes 30 and the blades 20. At the blades 20, the working fluid 13 relaxes impulsively, so that the blades 20 drive the rotor 3 and this the driven machine coupled to it. Preferably, the burner 7 is used in conjunction with a so-called tube combustion chamber 6 (FIG. 2). Here, the gas turbine 1 a plurality of annularly arranged

Pipe combustion chambers 6, the outflow openings open into the annular hot gas duct 11 turbine inlet side. These are preferably at each of these

Pipe combustion chamber a plurality, for example six or eight, burner 7 at the opposite end of the downstream opening of the tube combustion chamber 6 is usually arranged in a ring around a pilot burner.

Figure 2 shows a section of a tube burner 7 schematically. The burner 7 comprises a head end 51, a transition 52 and a liner 53 therebetween. As the "head end 51", the term "head end 51" is substantially the same as that of FIG

Part of the fuel injection 55 / fuel-air premix 56 of the burner referred to. The liner 53

extends from the head end to the transition 52

any way. By liner 53 and flow jacket 60, an annular passage 57 is formed by the combustion / cooling air 65 flows. The room in front of the

Fuel injection 55 or fuel / air premix 56 is referred to as plenum 100. The burner 7 has a plenum wall with a plenum top wall 170 and a

Plenum sidewall 150 on. At least that is

Plenumsoberwand 170 seen in the flow direction before the

Head end 51 is arranged, whereby a plenum 100 is formed between the plenum top wall 170 and the head end 51. The Plenum wall has a plenum facing side 140 and a side facing away from the plenum 120 (FIG. 3).

FIG. 3 shows the burner system according to the invention

at least one burner 7 with a combustion chamber 6 and a head end 51. Detailed investigations of the mode distribution in the combustion chamber 6 have shown that the

Sound pressure distribution in plenum 100 upstream of the combustion chamber 6 has a noticeable effect on the sound pressure in the

Combustion chamber 6 has. By suppressing the pressure fluctuations in the plenum 100, the formation of the typical eigenmodes of the combustion chamber 6 can also be reduced or completely prevented. Therefore, according to the invention, the plenum wall has on its side facing away from the plenum 120 at least one resonator 200, generally more than one Helmholtz resonator 200. These suppress the pressure oscillations in the plenum 100 in front of the combustion chamber 6. This is particularly advantageous when it comes to tube combustion chambers 6. The resonator 200 in this case has a neck 201, which is adjustable in length. This can be realized via an adjustable sleeve. Thus, different frequencies can be damped.

The Helmholtz resonators 200 are provided at the plenum facing away from plenum side wall 120. There is a realization particularly easy to implement. In addition, so are speed fluctuations in the field of

Fuel injection 55 and the fuel-air premix 56 prevented.

Advantageously, only the resonator neck 201 has openings to the plenum 100. The realization of the Helmholtz resonators 200 in the region of the plenum 100 gives the advantage over the attachment to the combustion chamber lower temperatures than when mounted on the

Combustion chamber outside. A flow through the Helmholtz resonators 200 with cooling air is therefore not necessary. This eliminates the need for cooling holes on the Helmholtz resonators 200, which reduce the effectiveness of the Helmholtz Reduce resonators 200. Due to the lower temperatures and by the avoidance of hot exhaust gas flowing into the Helmholtz resonator 200, it is also significantly easier to accommodate friction and turbulence-increasing internals in the resonator neck 201, which significantly increases the effectiveness of the Helmholtz resonator 200.

Claims

claims

A burner system comprising at least two adjacent burners (7), each having at least one combustion chamber (6) and a head end (51), the latter being at least one

Fuel injection (55) and a fuel-air

Wherein the burner (7) includes a plenum (100) upstream of the fuel-air premix (56), the plenum (100) being defined by a plenum wall having a plenum top wall (170) and a plenum side wall (FIG. 150), the plenum top wall (170) being disposed upstream of the head end (51), the plenum side wall (150) being disposed at least partially upstream of the head end (51), the plenum wall facing one of the plenum Page (140) and one in plenary

has opposite side (120)

d a d u r c h e n c i n e, the s

Plenumswand on its side facing away from plenum (120) has at least one resonator.

2. Burner system according to claim 1,

d a d u r c h e n c i n e, the s

Plenumsseitenwand (150) is at least partially disposed around the head end (51) around, and that while the

Plenumsseitenwand (150) in a radial direction (r) from the head end (51) is spaced apart.

3. Burner system according to claim 2,

There is a channel (125) through the plenum side wall (150) and the head end (51).

4. Burner system according to one of the preceding claims, d a d u c h e c e n e c e s e s, d a s s

Resonator is a Helmholtz resonator (200).

5. Burner system according to one of the preceding claims, characterized in that the

Resonator (200) has a neck (201).

6. Burner system according to one of claims 5,

In other words, only the resonator neck (201) has openings to the plenum (100).

7. Burner system according to one of the preceding claims, wherein a plurality of burners (7) are provided, wherein each burner (7) engages

Plenum having a plenum wall with at least one resonator on the side facing away from the plenum (120).

8. Gas turbine with a compressor, a turbine and a burner system according to one of the preceding claims.