CERAMIC RESONATOR FOR COMBUSTION CHAMBER SYSTEMS AND COMBUSTION CHAMBER SYSTEM

Abstract

A ceramic resonator for combustion chamber systems and combustion chamber system, wherein the resonator is annular when seen in the axial throughflow direction and has cavities in the interior, the cavities having at least one resonator neck per cavity as a connection to the inner surface of the ceramic resonator. By using a ceramic resonator, the amount of cooling air required is significantly reduced.

Description

FIELD OF INVENTION

The invention relates to a resonator, in particular a Helmholtz resonator, which is used in combustion chambers, in particular in combustion chamber systems of turbines, in particular gas turbines.

BACKGROUND OF INVENTION

Tubular combustion chamber systems of stationary gas turbines generally consist of one or more combustion chamber components connected axially in series between the burner outlet and the turbine inlet. Thus, the tubular combustion chamber types made by Siemens AG have a system consisting of a “basket” and a “transition”. This system carries the combustion gases from the burner in the direction of the turbine inlet. Owing to the high combustion temperatures, the tubular combustion chamber components are usually based on thin-walled Ni-based materials with internal cooling ducts and a layer system for thermal insulation (ceramic+metallic bonding layer).

In or downstream of the flame region, the tubular combustion chamber systems have circumferentially arranged resonators in order to reduce acoustic combustion oscillations. The resonator region limits the service life of the respective component (“basket” or “transition”). The production of the resonators is complex and expensive.

The resonator region has relatively large cooling air surfaces and is intensively cooled or flowed through. In this respect, the cooling air requirement is relatively high in relation to the overall tubular combustion chamber system.

SUMMARY OF INVENTION

It is therefore the object of the invention to solve the problem mentioned above.

The object is achieved by a ceramic resonator as claimed and a combustion chamber system as claimed.

The subclaims list further advantageous measures which can be combined with one another as desired in order to achieve further advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures and the description represent only exemplary embodiments of the invention.

More specifically:

FIG. 1 shows a ceramic resonator,

FIG. 2 shows a cross section according to FIG. 1, and

FIG. 3 shows a cross section of the ceramic resonator in the installed state of a combustion chamber system.

DETAILED DESCRIPTION OF INVENTION

The ceramic resonator according to the invention based on the Helmholtz principle replaces a metallic welded construction of a resonator system of a tubular combustion chamber.

The ceramic resonator 1 according to the invention (FIG. 1) is a ceramic component which is of ring-shaped design (oval or circular) or is designed as a one-piece ring, segmented or as a segmented ring, with inner cavities 16′, 16″, . . . (FIG. 2).

These cavities 16′, 16″, . . . are open toward the inner surface 7, the hot-gas side, in order to permit damping in accordance with the Helmholtz principle.

Moreover, it is possible to open the cavities 16′, 16″, . . . also toward the cold-gas side 4, should this be necessary.

The cavities 16′, 16″, . . . are to be adapted and configured in size, shape, number, distribution and/or resonator necks to match the frequency to be damped. The size, shape, number, distribution and resonator necks can be varied within the ceramic resonator 1.

It is also possible in particular to configure cavities with a plurality of openings toward the hot-gas side.

Advantages:

• • reduction of production and life cycle costs by means of a ceramic resonator ring which can be produced at low cost
  • reduced high-temperature requirements for the metallic material of the supporting structure
  • reduced repair/reprocessing costs as a result of the elimination of decoating and recoating
  • increase in maintenance intervals through the avoidance of crack-inducing high temperature gradients in the metallic supporting structure
  • reduction of the cooling air requirement in comparison with radial-flow metallic resonators
  • transferability to tubular combustion chamber systems from competitors.

FIG. 1 shows a ceramic resonator 1, which is advantageously designed as a ring or in a ring shape with a circular or oval cross section when viewed in the axial direction 10 (throughflow direction).

The ceramic resonator 1 can also be of segmented construction, i.e. can consist of two half-shells or a plurality of segments (neither option being illustrated).

The ceramic resonator 1 has an outer surface 4 (cold-gas side) and an inner surface 7 (hot-gas side), openings 13, 13′ being present on the inner surface 7 of resonator necks 14′, . . . , which project, in particular radially, into the ceramic resonator 1 and open into cavities 16′, 16″, . . . (FIG. 2, FIG. 3).

The inner surface 7 delimits a hot-gas stream which flows through the ceramic resonator 1 in the axial throughflow direction 10 and with respect to which the ceramic resonator is advantageously concentrically aligned.

FIG. 2, in a section (parallel to the axial throughflow direction 10) according to FIG. 1, shows cavities 16′, 16″, . . . , which are advantageously spherical and/or oval, cuboidal and/or cube-shaped or have a surface which is curved in some other way and/or has a different type of geometry in respect of its angles and edges.

The geometry of the cavities 16′, 16″, . . . used can be the same for each ceramic resonator 1, but it may also be varied within the ceramic resonator 1.

Starting from this cavity 16′, 16″, . . . there is, in particular, just one resonator neck 14′, . . . , which ends in an opening 13′ on the inner surface 7 of the ceramic resonator 1.

There may also be a plurality of necks per cavity 16′, 16″, . . . (not illustrated).

The cavities 16′, 16″, . . . are advantageously arranged uniformly, as illustrated in FIGS. 1 and 2, or in a nonuniformly distributed manner (not illustrated) and advantageously have the same or different geometries in respect of the diameter of the resonator necks 14′, . . . , the length of the resonator necks 14′, . . . and/or the shape of the cavity 16′, 16″. Other distributions which are uniformly arranged and differ from the figures are possible.

Here in FIGS. 1 and 2, the cavities 16′, 16″, . . . are arranged offset in relation to one another and uniformly in the circumferential direction 12.

The side faces 19′, 19″ of the ceramic resonator 1 are advantageously designed to be conical and/or at right angles to the inner 7 and outer surface 4 in order to allow installation in a combustion chamber system 20 or resonator housing 23 (FIG. 3).

The ceramic resonator 1 is advantageously arranged in a corresponding protrusion 29 as part of a metallic supporting structure 29 of the resonator housing 23 for the ceramic resonator 1 of a combustion chamber system 20 (FIG. 3). The axial flow direction 10 of the hot gas is again illustrated, whereas the direction 26 represents the direction of the cooling air in the opposite direction, starting from the compressor.

The ceramic used for the resonator 1 is advantageously a refractory ceramic, advantageously an Al₂O₃ refractory ceramic.

• The porosity of the ceramic resonator 1 is advantageously ≥2 vol % and, in particular, ≤20 vol %.

The dimensions of an exemplary ceramic resonator 1 are advantageously: inside diameter 400 mm, thickness 30 . . . 40 mm, length 200 mm.

Claims

1. A ceramic resonator, comprising: a ring-shaped design when seen in an axial throughflow direction, andcavities in the interior,wherein the cavities have at least one, resonator neck per cavity as a connection to an inner surface of the ceramic resonator.

2. The ceramic resonator as claimed in claim 1, wherein the ceramic resonator is of one-piece construction.

3. The ceramic resonator as claimed in claim 1, wherein the ceramic resonator consists of two or more segments.

4. The ceramic resonator as claimed in claim 1, wherein the at least one, in particular all, cavities is/are of spherical design.

5. The ceramic resonator as claimed in claim 1, wherein the at least one, in particular all, cavities is/are of oval design.

6. The ceramic resonator as claimed in claim 1, wherein the at least one, in particular all, cavities is/are of cuboidal design.

7. The ceramic resonator as claimed in claim 1, wherein the at least one, in particular all, cavities is/are of cube-shaped design.

8. The ceramic resonator as claimed in claim 1, comprising: a plurality of cavities along an axial throughflow direction, and a plurality of cavities in a radial circumferential direction.

9. The ceramic resonator as claimed in claim 1, wherein the cavities are uniformly distributed in relation to the inner surface of the ceramic resonator, at least in some region or regions, in particular completely,very particularly being offset from one another in a radial circumferential direction.

10. The ceramic resonator as claimed in claim 1, wherein the cavities are nonuniformly distributed in relation to the inner surface, at least in some region or regions, in particular completely.

11. The ceramic resonator as claimed in claim 1, wherein the ceramic resonator consists only of ceramics,in particular in which a refractory ceramic is used as the ceramic, preferably an Al2O3 refractory ceramic.

12. The ceramic resonator as claimed in claim 1, wherein the porosity of the ceramic resonator is ≥2 vol % and in particular ≤20 vol %.

13. The ceramic resonator as claimed in claim 1, wherein the ceramic resonator is of rectangular or trapezoidal design in cross section parallel in the axial throughflow direction.

14. The ceramic resonator as claimed in claim 1, wherein there is only one resonator neck per cavity.

15. The ceramic resonator as claimed in claim 1, wherein there is a plurality of resonator necks per cavity.

16. A combustion chamber system, comprising: a ceramic resonator as claimed in claim 1.

17. The combustion chamber system as claimed in claim 16, comprising: a resonator housing,wherein the resonator housing has a corresponding receptacle for the ceramic resonator.

18. The ceramic resonator as claimed in claim 1, wherein the ceramic resonator has a circular or oval cross section.

19. The ceramic resonator as claimed in claim 1, wherein the cavities have only one resonator neck per cavity.