EP3663548B1

EP3663548B1 - Damper for a combustor assembly of a gas turbine power plant and combustor assembly comprising said damper

Info

Publication number: EP3663548B1
Application number: EP18210858.9A
Authority: EP
Inventors: Alessandro Scarpato; Christoph Gaupp; Mirko Ruben Bothien; Michael Thomas Maurer; Frédéric BOUDY
Original assignee: Ansaldo Energia Switzerland AG
Current assignee: Ansaldo Energia Switzerland AG
Priority date: 2018-12-06
Filing date: 2018-12-06
Publication date: 2022-05-25
Anticipated expiration: 2038-12-06
Also published as: EP3663548A1; CN111288492A; CN111288492B

Description

TECHNICAL FIELD

The present invention relates to a damper for a combustor assembly of a gas turbine and to a combustor assembly of a gas turbine comprising said damper. In particular, the present invention relates to a damper for a sequential combustor assembly.

BACKGROUND

As known, a gas turbine power plant comprises a compressor, a combustor assembly and a turbine.
In particular, the compressor is supplied with air and comprises a plurality of blades compressing the supplied air. The compressed air leaving the compressor flows into a plenum, i.e. a closed volume delimited by an outer casing, and from there into the combustor assembly. In the combustor assembly the compressed air and at least one fuel are combusted.
The resulting hot gas leaves the combustor assembly and is expanded in the turbine performing work.
In order to achieve a high efficiency, high temperatures are required during combustion. However, due to these high temperatures, high NOx emissions are generated.
In order to reduce these emissions and to increase operational flexibility, sequential combustor assemblies can be used.
In general, a sequential combustor assembly comprises two combustors in series: a first-stage combustor and a second-stage combustor, which is arranged downstream the first-stage combustor along the gas flow.
Of course, a combustor assembly with a single combustion stage can be also used.
During operation, inside the combustor assembly pressure oscillations may occur causing mechanical damages and limiting the operating regime. Mostly combustor assemblies, in fact, have to operate in lean mode for compliance to pollution emissions. The burner flame during this mode of operation is extremely sensitive to flow perturbations and can easily couple with dynamics of the combustor to lead to thermo-acoustic instabilities. For this reason, usually combustor assemblies are provided with damping devices, in order to damp these pressure oscillations.
Known dampers comprise one damper volume that acts as a resonator volume and a neck fluidly connecting the damper volume to at least one inner chamber of the combustor assembly.
Examples of dampers of this kind are disclosed in documents EP23977 61 , EP2397759 and US2018156460A1 , which disclose the preamble of claim 1.
However, this kind of dampers are not sufficiently flexible. In some applications, in fact, it is necessary to damp oscillations having frequencies very far from each other.

SUMMARY

The object of the present invention is therefore to provide a damper for a combustor assembly, which is flexible, simple and economical, both from the functional and the constructive point of view.
According to the present invention, there is provided a damper for a combustor assembly of a gas turbine plant comprising a first damper body, which defines at least one first damping volume and comprises at least one opening; a neck coupled to the opening of the first damper body and configured for fluidly connecting the first damping volume with a combustion chamber of the combustor assembly; and a second damper body, which extends, at least in part, about at least a portion of the neck and defines at least one second damping volume; the second damper body comprising at least one opening configured for fluidly connecting the second damping volume to the combustion chamber of the combustor assembly; the second damper body comprises a plurality of second damping volumes, each of which is fluidly connected to the combustion chamber of the combustor assembly by means of a respective plurality of openings.
The structure of the damper according to the invention is very compact and flexible.
The flexibility is given by the possibility of damping different frequencies, as the damping volumes can be sized opportunely depending on the needs.
The compact structure allows satisfying the strict dimensional constraints of the modern combustor assemblies. In modern combustor assemblies, in fact, the spaces available for traditional dampers installation are few and, additionally, these spaces are not always arranged where acoustic damping is really needed. The compact structure of the damper according to the present invention allows also the installation in positions closer to the zones where damping is really needed. Moreover, thanks to its compactness, the damper according to the present invention can be used for replacing most of the existing dampers.
In other words, thanks to the damper according to the present invention a broadband damping of combustion dynamics is obtained with a very compact structure.
Moreover, the second damper body has a more flexible structure as each second damping volume can be opportunely configured and sized so as to damp one or more frequency.
According to a variant of the present invention, the second damper body is annular. In this way the structure of the damper is simple and easy to manufacture.
According to a variant of the present invention, the neck has a first end connected to the opening and a second end facing an area in fluid communication with the combustion chamber; the second damper body extending about the second end. In this way the second damper body is closer to the area in fluid communication with the combustion chamber.
According to a variant of the present invention, the second damper body comprises a plurality of openings fluidly connecting the second damping volume to the combustion chamber of the combustor assembly. In this way, the vortices created at the openings maximize acoustic energy absorption.
According to a variant of the present invention, the second damping volumes are evenly distributed in the second damper body. In this way the structure of the damper is simple and easy to manufacture.
According to a variant of the present invention, the second damping volumes are identical to each other. In this way the absorption is maximized in a given frequency band.
According to a variant of the present invention, the second damper body having an axial length, which is smaller than the axial length of the neck.
According to a variant of the present invention, the second damper body comprises at least one auxiliary opening fluidly connecting the second damping volume to a source of air. This air has two functions: cooling the damper surface (which is typically facing the flame), and avoiding hot gas ingestion (which would de-tune the second damper body and could cause damages to the second damping body itself).
According to a variant of the present invention, the first damper body and the neck are configured and dimensioned so as to damp at least one first frequency comprised in a first frequency band and the second damper body is configured and dimensioned so as to damp at least one second frequency comprised in a second frequency band; the first frequency and the second frequency are different from each other. Preferably, the first frequency band is 50-1000 Hz and the second frequency band is 1000-10000 Hz.
According to a variant of the present invention, the first damper body and the neck are made as a single body.
According to a variant of the present invention, the first damper body, the neck and the second damper body are made as a single body.
It is also another object of the present invention to provide a reliable combustor assembly for a gas turbine plant where acoustic oscillations are reduced.
According to this object the present invention relates to a combustor assembly comprising at least one damper as described above.
According to a variant of the present invention, the combustor assembly extends along a longitudinal axis and comprises at least one center hollow body arranged along the longitudinal axis and a plurality of lobes extending radially from the center hollow body; the damper is arranged, at least in part, in the center hollow body.
The integration of the damper into the central hollow body has several advantages: it is an ideal location to damp combustion dynamics as it is close to the flame and it is the best location to damp radial acoustic modes.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, which illustrate some non-limitative embodiment, in which:

Figure 1 is a schematic representation of a gas turbine assembly;
Figure 2 is a perspective view, with parts removed for clarity, of a damper according to the present invention;
Figure 3 is a lateral section view, with parts removed for clarity, of the damper of figure 2;
Figure 4 is a lateral schematic view, with parts in section and parts removed for clarity, of a detail of a combustor assembly according to the present invention;
Figure 5 is a lateral schematic view, with parts in section and parts removed for clarity, of a detail of a combustor assembly according to a first variant of the present invention;
Figure 6 is a lateral schematic view, with parts in section and parts removed for clarity, of a detail of a combustor assembly according to a second variant of the present invention;
Figure 7 is a lateral schematic view, with parts in section and parts removed for clarity, of a detail of a combustor assembly according to a third variant of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In figure 1 reference numeral 1 indicates a gas turbine assembly. The gas turbine assembly 1 comprises a compressor 2, a sequential combustor assembly 3 and a turbine 5. The compressor 2 and the turbine 3 extend along a main axis A.
In use, an airflow compressed in the compressor 2 is mixed with fuel and is burned in the sequential combustor assembly 3. The burned mixture is then expanded in the turbine 5 and converted in mechanical power by a shaft 6, which is connected to an alternator (not shown).
The sequential combustor assembly 3 comprises a first-stage combustor 8 and a second-stage combustor 9 sequentially arranged along the gas flow direction G. In other words, the second stage combustor 9 is arranged downstream the first stage combustor 8 along the gas flow direction G.
Preferably, between the first stage combustor 8 and the second stage combustor 9 a mixer 11 is arranged.
The first stage combustor 8 defines a first combustion chamber 14, the second stage combustor 9 defines a second combustion chamber 16, while the mixer 11 defines a mixing chamber 17.
The first combustion chamber 14, the second combustion chamber 16 and the mixing chamber 17 are in fluidic communication and are defined by a liner 18 (see figure 4 wherein it is partially visible), which extends along a longitudinal axis B, preferably parallel to the main axis A.
With reference to figure 4, in the second combustion chamber 16 of the second stage combustor 9 a supply assembly 20 is arranged.
The supply assembly 20 comprises a central hollow body 21 and a plurality of lobes 22 (schematically represented in figure 4), each of which extends radially about the central hollow body 21. In the energy field the central hollow body 21 can be called also "central nose".
The lobes 22 are preferably defined by streamlined bodies, each of which is provided with a plurality of nozzles 24 and is supplied with air and at least one fuel.
Preferably, a connection 25 between an inner air channel 26 of at least one lobe 22 and an inner chamber 27 of the central hollow body 21 is realized in order to allow air entering in the inner chamber 27. In figure 4 the connection 25 is represented schematically.
In the inner chamber 27 of the central hollow body 21 a damper 30 is arranged. As will be discussed later on, the damper 30 is arranged inside the inner chamber 27 to damp the fluctuations inside the second stage combustor 9.
Referring to figures 2 and 3, damper 30 extends along an extension axis C and comprises a first damper body 31, a neck 33 and a second damper body 34 extending, at least in part, about the neck 33.
The first damper body 31 defines at least one first damping volume 35 and comprises at least one opening 36 (only visible in figure 3) connected to the neck 33. Preferably, the first damper body 31 is a cylindrical body and comprises at least one further opening 37 for the passage of air.
Air, in fact, contributes to cool the first damper body 31, and avoid hot gas ingestion (which would de-tune the first damper body 31 and could cause damages to the first damping body 31 itself) .Preferably, the opening 36 and the further opening 37 are arranged on opposite faces of the first damper body 31.
The neck 33 is configured for fluidly connecting the first damping volume 35 with a combustion chamber. In the non-limiting example here disclosed and illustrated, the neck 33 fluidly connects the first damping volume 35 to the second combustion chamber 16.
In particular, the neck 33 has a first end 40 connected to the opening 36 and a second end 41 facing an area in fluid communication with a combustion chamber. In the non-limiting example here illustrated the second end 41 faces into the second combustion chamber 16.
The second damper body 34 is preferably annular and extends about at least a portion of the neck 33.
Preferably, the second damper body 34 extends about the second end 41 of the neck 33 and has an axial length L1 smaller that the axial length L2 of the neck 33.
The second damper body 34 comprises at least one second damping volume 44 and comprises at least one opening 45 fluidly connecting the second damping volume 44 to a combustion chamber (i.e. the second combustion chamber 16 in the non-limiting example here illustrated).
Preferably, the second damper body 34 comprises a plurality of openings 45 fluidly connecting the second damping volume 44 to a combustion chamber.
The plurality of openings 45 can be sized (diameter and axial inner length) and arranged so as to obtain the maximum resonance absorption. In the non-limiting example here illustrated the openings 45 are substantially arranged as a matrix. The openings 45 can alternatively be arranged in a circumferential pattern.
The openings 45 can also have different sizes and shapes (rectangular, slots, oval, etc.)
Preferably, the second damper body 34 comprises a plurality of second damping volumes 44 evenly distributed. Preferably the second damping volumes 44 are identical to each other.
According to a variant not shown, the second damping volumes 44 have different volumes in order to maximize the absorption bandwidth.
Each second damping volume 44 is fluidly connected to a combustion chamber by means of a plurality of openings 45 (arranged as a matrix in the example here illustrated).
Preferably, the second damper body 34 is provided with at least one auxiliary opening 48 for the passage of air into the second damping volume 44.
Preferably, the second damper body 34 comprises one auxiliary opening 48 for each second damping volume 44.
According to a variant not disclosed, the second damper body 34 is provided with at least one fluidic connection between the damping volume 44 and the neck 33, preferably instead of the auxiliary opening. In this way the air distribution layout is simplified and there is also the possibility of having a near wall cooling feature.
Preferably, the damper 30 is dimensioned to damp planar waves and transverse waves.
In particular, the first damper body 31 and the neck 33 are configured and dimensioned to damp planar waves, while the second damper body 34 is configured and dimensioned to damp transverse waves.
Planar waves are waves having a planar wave front and a constant amplitude in the planar wave front, while transverse waves have a non-planar wave front.
The damper 30 is preferably dimensioned so as to damp at least two different frequencies. In particular the damper 30 is dimensioned to damp at least one frequency comprised in a first band (50-1000 Hz) and at least one second frequency comprised in a second frequency band (1000-10000 Hz).
In particular, the first damper body 31 and the neck 33 are configured and dimensioned so as to damp a frequency comprised in the first band, while the second damper body 34 is configured and dimensioned so as to damp a frequency comprised in the second band.
Preferably, the first damper body 31 and the neck 33 are made as a single body.
More preferably, the first damper body 31, the neck 33 and the second damper body 34 are made as a single body.
Preferably, the damper 30 is realized by means of an additive manufacturing technique.
The definition "additive manufacturing technique" here means all the rapid manufacturing techniques using layer-by-layer constructions or additive fabrication. This definition includes, but it is not limited to, selective laser melting (SLM), selective laser sintering (SLS), Direct Metal Laser Sintering (DMLS), 3D printing, sterolithography, direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM) laser engineered net shaping (LENS), laser net shape manufacturing (LNSM) and direct metal deposition (DMD).
It is understood that damper 30 can be arranged also in another portion of the combustor assembly 3.
For example, damper 30 can be coupled to the liner 18, preferably to the portion of the liner 18 facing the second combustion chamber 16.
In figure 5 it is shown a first variant of the combustor assembly 3, comprising at least two dampers 30 coupled to a combustor front panel 28 around the supply assembly 20. The dampers 30 are arranged so as the extension axis C is parallel to the longitudinal axis B.
In figure 6 it is shown a second variant of the combustor assembly 3, comprising at least two dampers 30a, coupled to the combustor liner 18 and arranged on opposite sides of the liner 18 with respect to the longitudinal axis B, and at least one damper 30b arranged inside the inner chamber 27. Damper 30b is arranged inside the inner chamber 27 so as the extension axis C is transversal to the longitudinal axis B, while dampers 30a are arranged so as the extension axis C is orthogonal to the longitudinal axis B.
In figure 7 it is shown a third variant of the combustor assembly 3 wherein the supply assembly 20 is defined by at least two burners 29 axially extending in the combustor assembly 3 which are supported by a combustor front panel 28.
The combustor assembly 3 comprises a damper 30 arranged substantially along the longitudinal axis B between the burners 29. Extension axis C of the damper 30 preferably coincides with longitudinal axis B.

Claims

Damper for a combustor assembly (3) of a gas turbine plant comprising:
- a first damper body (31), which defines at least one first damping volume (35) and comprises at least one opening (36);

- a neck (33) coupled to the opening (36) of the first damper body (31) and configured for fluidly connecting the first damping volume (35) with a combustion chamber (15; 14) of the combustor assembly (3);

- a second damper body (34), which extends, at least in part, about at least a portion of the neck (33) and defines at least one second damping volume (44); the second damper body (34) comprising at least one opening (45) configured for fluidly connecting the second damping volume (44) to the combustion chamber (15;14) of the combustor assembly (3);
the damper being characterized in that the second damper body (34) comprises a plurality of second damping volumes (44), each of which is configured to be fluidly connected to the combustion chamber (15; 14) of the combustor assembly (3) by means of a respective plurality of openings (45).
Damper according to claim 1, wherein the second damper body (34) is annular.
Damper according to claim 1 or 2, wherein the neck (33) has a first end (40) connected to the opening (36) and a second end (41) which is configured for facing an area in fluid communication with the combustion chamber; the second damper body (34) extending about the second end (41) .
Damper according to anyone of the foregoing claims, wherein the second damper body (34) comprises a plurality of openings (45) configured for fluidly connecting the second damping volume (44) to the combustion chamber (15; 14) of the combustor assembly (3).
Damper according to anyone of the foregoing claims, wherein the second damping volumes (44) are evenly distributed in the second damper body (34).
Damper according to anyone of the foregoing claims, wherein the second damping volumes (44) are identical to each other.
Damper according to anyone of the foregoing claims, extending along an extension axis (B); the second damper body (34) having an axial length (L1) which is smaller than the axial length (L2) of the neck (33).
Damper according to anyone of the foregoing claims, wherein the second damper body (34) comprises at least one auxiliary opening (48) fluidly connecting the second damping volume (44) to a source of air.
Damper according to anyone of the foregoing claims, wherein the first damper body (31) and the neck (33) are configured and dimensioned so as to damp at least one first frequency comprised in a first frequency band and the second damper body (34) is configured and dimensioned so as to damp at least one second frequency comprised in a second frequency band; the first frequency and the second frequency are different from each other.
Damper according to claim 9, wherein the first frequency band is 50-1000 Hz and the second frequency band is 1000-10000 Hz.
Damper according to anyone of the foregoing claims, wherein the first damper body (31) and the neck (33) are made as a single body.
Damper according to anyone of the foregoing claims, wherein the first damper body (31), the neck (33) and the second damper body (34) are made as a single body.
Combustor assembly for a gas turbine plant comprising at least one damper (30) as claimed in anyone of the foregoing claims.
Combustor assembly according to claim 13, extending along a longitudinal axis (B) and comprising at least one center hollow body (21) arranged along the extension axis (B) and a plurality of lobes (22) extending radially from the center hollow body (21); the damper (30) being arranged, at least in part, in the center hollow body (21).