BURNER SYSTEM WITH RESONATOR

Abstract

The present invention relates to a burner system (1) comprising a pilot burner arrangement (2), a main burner arrangement (3) surrounding the pilot burner arrangement (2), a combustion chamber arranged downstream with respect to the pilot burner arrangement (2) and the main burner arrangement (3), and at least one resonator (17), wherein the main burner arrangement (3) defines a ring-shaped air supply (13) outwardly delimited by a burner cone (14) and provided with radially extending swirl vanes (15), wherein a resonator cavity (18) of the at least one resonator (17) is formed at the outside of the burner cone (14), wherein the resonator cavity (18) is provided with a plurality of resonator openings (20) defining a fluidic connection between the resonator cavity (18) and the combustion chamber.

Description

The present invention refers to a burner system comprising a pilot burner arrangement, a main burner arrangement surrounding the pilot burner arrangement, a combustion chamber arranged downstream with respect to the pilot burner arrangement and the main burner arrangement, and at least one resonator, wherein the main burner arrangement defines a ring-shaped air supply outwardly delimited by a burner cone and provided with radially extending swirl vanes. The swirl vanes can be fixed to the burner cone.

Burner systems of the above-mentioned kind are used for firing fluidic fuels in order to operate a turbo-engine, such as a gas turbine. During operation burner systems are prone to combustion dynamics, which may arise as a result of a flame excitation, aerodynamic induced excitation or insufficient damping. The combustion dynamics may cause high acoustic noises as well as damages to components of the burner system. In order to solve this problem, it is known to perform acoustic damping of critical frequencies by means of resonators, which are, for example, directly fixed to the outer wall of the combustion chamber.

It is an object of the present invention to provide a burner system of the above-mentioned kind having an alternative structure.

In order to solve this object the present invention provides a burner system of the above-mentioned kind, which is characterized in that a resonator cavity of the at least one resonator is formed at the outside of the burner cone, wherein the resonator cavity is provided with a plurality of resonator openings defining a fluidic connection between the resonator cavity and the combustion chamber. Such an integral structure of the at least one resonator and the burner cone is advantageous in that the resonator only needs little installation space and can be produced at low costs. Moreover, the resonator is arranged immediately next to the combustion chamber. Accordingly, the critical frequencies can be damped right next to the place of origin.

Preferably the resonator cavity is designed in the form of a ring. Thus, the resonator cavity can be produced with a low number of parts. The ring-shaped resonator cavity can be divided by walls into sections. Each section can comprise at least one of the resonator openings.

According to one aspect of the present invention the resonator cavity is defined by at least one panel sheet fixed to the outside of the burner cone. Thus, the outer wall of the burner cone forms a part of the resonator, which is advantageous with respect to the costs of manufacture.

Preferably, the resonator openings are evenly spaced apart from each other.

According to one aspect of the present invention, the resonator openings are defined by tubes extending through a wall of the resonator cavity. Such tubes are advantageous in that their length, their diameter and their installation positions can be easily adapted to the frequencies, which are to be damped by means of the resonator.

Preferably, the resonator openings are directed towards the combustion chamber.

Further features and advantages of the present invention will become apparent by means of the following description of a burner system according to one embodiment of the present invention with reference to the accompanying drawing. In the drawing

FIG. 1 is a schematic sectional view of a gas turbine according to the prior art,

FIG. 2 is a schematic representation of a part of a burner system according to one embodiment of the present invention and

FIG. 3 is a perspective cross sectional view of the burner system shown in FIG. 1.

The FIG. 1 shows a schematic sectional view of a gas turbine 1 according to the prior art. The gas turbine 100 has, in the interior, a rotor 300 which is mounted so as to be rotatable about an axis of rotation 200 and which has a shaft 400, said rotor also being referred to as turbine rotor. Arranged in succession along the rotor 300 are an intake housing 600, a compressor 800, a combustion system 900, a turbine 140, and an exhaust housing 150, the combustion system 900 having a number of combustors 100 which each comprise a burner arrangement 110 and a combustion chamber 120. The combustion system 900 communicates with a hot-gas duct, which is for example of annular form. There, multiple turbine stages positioned one behind the other form the turbine 140. Each turbine stage is formed from rings of blades. In the hot-gas duct, as viewed in the flow direction of a working medium, a row formed from guide blades 170 is followed by a row formed from rotor blades 180. Here, the guide blades 170 are fastened to an inner housing of a stator 190, whereas the rotor blades 180 of a row are for example attached via a turbine disk to the rotor 300. A generator (not illustrated), for example, is coupled to the rotor 300.

During the operation of the gas turbine, air is drawn in through the intake housing 600, and compressed, by the compressor 800. The compressed air L″ that is provided at the turbine-side end of the compressor 800 is conducted via a burner plenum 700 to the combustion system 900 and, in the latter, is mixed with a fuel in the region of the burner arrangement 110. Then, with the aid of the burner arrangement 110, the mixture is burned so as to form a working gas stream in the combustion system 900. From there, the working gas stream flows along the hot-gas duct past the guide blades 170 and the rotor blades 180. The working gas stream expands at the rotor blades 180 so as to impart an impetus thereto, such that the rotor blades 180 drive the rotor 300, and said rotor drives the generator (not illustrated) that is coupled thereto.

The FIGS. 2 and 3 show a burner system 1 according to an embodiment of the present invention. The burner system 1 comprises a pilot burner arrangement 2, a main burner arrangement 3 surrounding the pilot burner arrangement 2 and a combustion chamber (not shown) arranged downstream with respect to the pilot burner arrangement 2 and the main burner arrangement 3. The pilot burner arrangement 2 and the main burner arrangement are both designed to be operated with gaseous and/or liquid fuels. However, it should be noted, that the burner system 1 can also be configured to be operated merely with gaseous or merely with liquid fuels.

The pilot burner arrangement 2 comprises an oil supply 4 leading to an oil nozzle 5 facing towards the combustion chamber. Moreover, the pilot burner arrangement 2 has a gas supply 6 surrounding the oil supply 4. The gas supply 6 is again surrounded by an air supply 7 provided with swirl vanes 8 in a known fashion.

The main burner arrangement 3 comprises a gas supply 9 leading to a ring-shaped gas chamber 10, an oil supply 11 leading to a ring-shaped oil chamber 12, and a ring-shaped air supply 13 outwardly delimited by a burner cone 14 and provided with radially extending swirl vanes 15 fixed to the burner cone 14. The swirl vanes 15 are provided with outlet nozzles 16, which are connected to either the gas chamber 10 or the oil chamber 12. The burner cone 14 is provided with a resonator 17. The resonator 17 comprises a ring-shaped resonator cavity 18, which is defined by a panel sheet 19 fixed to the outside of the burner cone 14, and a plurality of resonator openings 20 defining a fluidic connection between the resonator cavity 18 and the combustion chamber. The resonator openings 20 are formed by tubes 21. The tubes 21 extend through a wall of the resonator 17, are arranged evenly spaced apart from each other along the perimeter of the resonator 17 and are directed towards the combustion chamber.

During the operation of the burner system 1 gas delivered by the gas supply 9 or oil delivered by the oil supply 11 is distributed within the ring-shaped gas chamber 10 or the ring-shaped oil chamber 12 and is injected in the airflow guided through the air supply 13 by means of the outlet nozzles 16 formed in the swirler vanes 15. The fuel-air-mixture is then discharged in the combustion chamber, where it is burned. The pilot burner arrangement 2 stabilizes the combustion within the combustion chamber. The combustion causes combustion dynamics, which can lead to high acoustic noises as well as to damages to components of the burner system 1. In order to eliminate dangerous combustion dynamics, critical frequencies are damped by means of the resonator 17. The critical frequencies to be damped by the resonator 17 can be adjusted by means of an appropriate choice of the size of the resonator cavity 18 as well as of the length, diameter and position of the resonator openings 20 defined by the tubes 21.

Even though the present invention was described herein by means of a detailed embodiment, it should be noticed that the present invention is not limited by the embodiment. It is rather possible for a skilled person to derive modifications and variations from the embodiment without leaving the scope of protection defined in the accompanying claims.

Claims

1. Burner system comprising a pilot burner arrangement, a main burner arrangement surrounding the pilot burner arrangement, a combustion chamber arranged downstream with respect to the pilot burner arrangement and the main burner arrangement, and at least one resonator, wherein the main burner arrangement defines a ring-shaped air supply outwardly delimited by a burner cone and provided with radially extending swirl vanes, wherein a resonator cavity of the at least one resonator is formed at the outside of the burner cone, wherein the resonator cavity is provided with a plurality of resonator openings defining a fluidic connection between the resonator cavity and the combustion chamber.

2. Burner system according to claim 1, wherein said resonator cavity is designed in the form of a ring.

3. Burner system according to claim 1, wherein said resonator cavity is defined by at least one panel sheet fixed to the outside of the burner cone.

4. Burner system according to claim 1, claim 1 said resonator openings are evenly spaced apart from each other.

5. Burner system according to claim 1, wherein said resonator openings are defined by tubes extending through a wall of the resonator.

6. Burner system according to claim 1, wherein said resonator openings are directed towards said combustion chamber.