EP1865259A2 - Gas-turbine combustion chamber wall for a lean-burning gas-turbine combustion chamber - Google Patents

Abstract

Fitted in a gas turbine combustor casing (2,3), combustor segments form a combustor wall (10) and are each impinged by cooling air with a film cooling via axial and/or radial cooling holes (16,17) fitted with a clearance from each other in an axial direction. In this area there are absorbing openings (19a) for introducing cooling air.

Description

The invention relates to a gas turbine combustor wall for a lean-burn gas turbine combustor.

The UK patent GB 2 309 296 describes a two-layer wall construction of a lean-burning gas turbine combustion chamber with an acoustically damping effect on high-frequency combustion chamber vibrations (indicated is a frequency band of 3 to 9 kHz) with simultaneous cooling of the combustion chamber wall. Both are achieved through the holes perpendicular through the wall. The outer / cold combustion chamber wall generates the impingement cooling jets on the inner / hot wall, the holes through the inner / hot wall discharge the impingement cooling air into the combustion chamber and generate the damping effect.

The EP 0 576 435 B1 describes a combustion chamber with a two-layer, subdivided into chambers wall structure, all holes are arranged at a shallow angle to the surface and therefore no damping effect is generated.

As a further prior art, the EP 0 971 172 A1 as well as the US 6,907,736 B2 called.

For cooling of combustion chambers, film cooling with cooling rings and effusion cooling is possible in the single-layer case, as well as shingles mounted in the multi-layered case (with pins on the back or impact-cooled) or soldered or welded sheet metal structures (Transply, Lamilloy). In the conventional film cooling, based on the cooling ring, the cooling air is thereby provided by holes or slots in the cooling rings, which generate the cooling film with or without deflection. These openings may be substantially radially mounted to realize delivery of the cooling air based on the static pressure of the cooling air supply, or substantially axially, to realize a supply by means of the total pressure of the air supply, or by both arrangement options simultaneously. In radial openings, a lip on the cooling ring is used, on which the air jets impact and are deflected in the axial direction. The axial and radial openings may be arranged in one or more rows. With several rows of openings in the axial direction, these are radially staggered and the lip is usually omitted.

A useful damping effect can only be achieved through openings that are mounted substantially perpendicularly through the combustion chamber wall. The best effect for suppressing combustion vibrations is achieved by dampers connected to the combustion chamber in the area of maximum heat release.

Effective film cooling is very limited by vertical openings, because of the lack of cooling effect limit the authors of the above patent, the scope of the damper on the part of the combustion chamber, which is located in the region of the divergent flame front and thus not even the maximum Heat release covers. In addition, a damping effect in the kHz range (specified 3 to 9 kHz) passes the requirements of lean combustion, since the first circumferential modes in the generally conventional annular combustion chambers, depending on the size in the range of 200 to 1000 kHz.

For effusion or transpiration cooling, the entire combustion chamber wall must contain openings, because areas without cooling openings would be uncooled. Even in the case of impingement cooling, the entire rear side of the area intended for cooling must be accessible, which does not guarantee the installation of dampers in the area of high heat release.

The invention has for its object to provide a gas turbine combustor wall of the type mentioned, which has both a good cooling and good damping with simple expansion and simple, cost manufacturability.

According to the invention, the object is achieved by the feature combination of the main claim, the dependent claims show further advantageous embodiment of the invention.

These dampers can be realized single-walled by the arrangement of openings substantially (plus minus 30 degrees to the surface normal) perpendicularly through the combustion chamber wall between the cooling rings, in which case the space between the combustion chamber and the combustion chamber housing acts as a damper volume.

The damper can also be designed as a two-walled construction, if the air consumption of the single-walled construction is perceived as too high. Here, a damper volume is separated by another housing on the outside of the combustion chamber, wherein the axial extent of the damper housing is limited by the distance of the cooling rings. The damper housing may be fixedly connected to the combustion chamber wall (e.g., bolted or welded to flanges) on either side, or only on one side (upstream or downstream end), with or without additional sealing on the sliding seat of the movable separation point. The flow of air through the damper is adjusted through holes in the damper housing which restrict compressor discharge air to the desired pressure in the damper. The damper volume communicates with the hot gas flow through substantially vertical damper ports through which the air flows slowly.

When one as well as the two-walled damper conveniently a plurality of openings in the Combustion chamber wall distributed in the region between the cooling rings in the axial and lateral directions. It may be advantageous to use different distances and cross-sectional areas of the openings on the circumference. The change in the distances and cross-sectional areas of the openings can be continuous or erratic. With regular spacing, one can only change the cross-sectional area of the openings or vary the distance with a constant cross-sectional area, or both.

The openings in the combustion chamber wall may be cylindrical bores or non-cylindrical openings. The non-cylindrical openings may contain a continuous (linear or non-linear) cross-sectional change or an abrupt, for example, from a small diameter to a larger diameter or vice versa. Also, the cross section of the openings themselves need not be round. It can also be oval, rectangular or star, shamrock or flower-shaped.

The throttle bores in the damper housing are usually round and without cross-sectional change, but may also vary in distance and diameter within the bore field.

The damper volume can be completely empty in the double-walled structure and form a circumferential space. It may be divided by partitions in the axial and / or lateral direction in chambers with three or more corners or the damper housing is not a circumferential structure, but extends in the circumferential direction only over a certain section. The circulating volume or the individual chambers may be filled all or partly with an air-permeable material. For example, the material may be a felt or web of fibers of a heat-resistant material, such as metal. Glass or ceramic or an open-pored sponge made of metal, ceramic or other heat-resistant material. The kind and the Properties of the filling material may be the same throughout the damper volume or all chambers or vary.

In order to reduce the air consumed by the acoustic damper in both variants, the application can be limited to the wall segments located near the maximum heat release zone or centrally between the burner and turbine vane (part between two cooling rings) where the effect is greatest. The dimensions of the damper and thus the frequency band damped by it can differ between the inner and the outer combustion chamber wall, as well between upstream and downstream of cooling rings limited portions of the combustion chamber and also in the circumferential direction within a combustion chamber segment.

To increase the heat resistance of the combustion chamber wall can be made of ceramic or CMC (ceramic matrix composite) instead of metal, as well as the damper housing, these parts need not be made of the same material.

If pure film cooling in the region of the dampers is not sufficient, effusion cooling holes at a shallow angle to the surface, e.g., between the damping holes, which pass through the wall substantially normal (at 90 degrees angle), may still be present. 20-30 degrees, which are fed by the same pressure level as the damper openings. Outside of the film cooling segments with acoustic dampers can also be improved by the attachment of effusion holes between the cooling rings or at the end of the combustion chamber to the turbine out at a shallow angle to the surface cooling.

To reduce the temperature of the combustion chamber wall, a ceramic thermal barrier coating between the cooling rings (combustion chamber segments) can be applied.

Since the damping holes no longer have to produce cooling effect (for which they are suitable only to a very limited extent), the cross section of the damping holes can be matched to the combustion chamber wall thickness and the damper volume or the distance of the combustion chamber wall to the combustion chamber housing or the damper housing, which also at frequencies below one kHz results in a significant attenuation effect. In the two-layer structure, there are further possibilities for tuning through the pressure in the damper housing and thus by controlling the flow velocity in the damper bores.

By changing the distances of the damping holes or their diameter different frequencies are attenuated. With sudden change in the Belochung further results damping effects.

With both variants, when using non-cylindrical openings, it is possible to optimize the damping effect while limiting the air consumption, since a small cross section of the inflow side leads to a small air throughput. In both variants, by increasing the edge line of the cross-section with constant effective flow cross-section (and thus constant air consumption) from about square to star, shamrock or, flower-shaped increase the production costs, the damping can be further increased.

Due to the high pressure difference across the cooling air holes creates a cooling film, which is very robust compared to the spin of the lean burner and the damper holes optimally protects against ingress of hot gas. In the axial position of the maximum heat release in the combustion chamber can now acoustic dampers with acoustically optimized Throughput can be used, which are tuned to the attenuation of frequencies below 1 kHz, for example, the frequency range of 300 to 1000 Hz.

A subdivision of the damper gap in the axial and lateral direction serves to prevent compensating flows in the damper housing. The introduction of air-permeable material into the damping volume can increase the damping.

By the above-described degrees of freedom in the damper design, a sufficient attenuation of all critical frequencies can be achieved. Through a suitable distribution of air between film and effusion cooling optimal cooling of the combustion chamber and thus a long life is achieved.

Fig. 1

eine schematische Darstellung einer Gasturbine mit Gasturbinenbrennkammer gemäß dem Stand der Technik,

Fig. 2

eine schematische Darstellung des Brennkammergehäuses sowie der Dampferwand und der Brennkammerwand gemäß dem Stand der Technik,

Fig. 3

eine schematische Darstellung eines ersten Ausführungsbeispiels, analog der Darstellung der Fig. 2,

Fig. 4

eine schematische Darstellung eines zweiten Ausführungsbeispiels. analog Fig. 3,

Fig. 5

eine weitere schematische Darstellung eines weiteren Ausführungsbeispiels,

Fig. 6

Darstellungsformen unterschiedlicher Querschnitte von Dämpfungsausnehmungen.

Fig. 7

eine schematische Darstellung eines weiteren Ausführungsbeispiels mit zweischichtigem Aufbau der Brennkammerwand,

Fig. 8

ein weiteres Ausführungsbeispiel, analog Fig. 7,

Fig. 9

ein weiteres Ausführungsbeispiel, analog den Fig. 7 und 8,

Fig. 10

eine schematische Darstellung einer Gasturbinenbrennkammer, analog Fig. 1, mit Anordnung der Brennkammersegmente in einschichtigem Aufbau, und

Fig. 11

eine schematische Darstellung, analog Fig. 10, mit Darstellung der Brennkammersegmente in zweischichtigem Aufbau.

In the following the invention will be described by means of embodiments in conjunction with the drawing. Showing:

Fig. 1

1 a schematic representation of a gas turbine with gas turbine combustion chamber according to the prior art,

Fig. 2

a schematic representation of the combustion chamber housing and the damper wall and the combustion chamber wall according to the prior art,

Fig. 3

1 is a schematic representation of a first exemplary embodiment, analogous to the representation of FIG. 2,

Fig. 4

a schematic representation of a second embodiment. analogous to FIG. 3,

Fig. 5

a further schematic representation of another embodiment,

Fig. 6

Representation forms of different cross-sections of Dämpfungsausnehmungen.

Fig. 7

a schematic representation of another embodiment with a two-layer structure of the combustion chamber wall,

Fig. 8

a further embodiment, analogous to FIG. 7,

Fig. 9

a further embodiment, analogous to FIGS. 7 and 8,

Fig. 10

a schematic representation of a gas turbine combustor, analogous to FIG. 1, with arrangement of the combustion chamber segments in a single-layer construction, and

Fig. 11

a schematic representation, analogous to FIG. 10, showing the combustion chamber segments in a two-layer construction.

In the embodiments, like parts are designated by like reference numerals.

FIG. 1 shows, in a schematic representation, a cross-section of a gas turbine combustion chamber according to the prior art. In this case, compressor outlet blades 1 and a combustion chamber outer housing 2 and a combustion chamber inner housing 3 are shown schematically. The reference numeral 4 denotes a burner with arm and head (diffusion flame). A combustion chamber head 5 is associated with a combustion chamber wall 6 with cooling rings 6a. Turbine inlet blades are designated by the reference numeral 7.

2 shows a schematic structure of a damper in detail view according to the prior art, wherein a combustion chamber wall 10 is provided with steaming and cooling holes 11 which each extend perpendicular to the combustion chamber wall 10. The compressor discharge air is indicated at 12, while flame and flue gas from the lean burn burner are indicated by the arrow 13. Between damper wall 9 and combustion chamber wall 10, a steam space 14 is provided. Cooling air is introduced into these through inflow bores 8.

In the embodiment shown in Fig. 3, the individual combustion chamber segments, which form a single-layer combustion chamber wall, with respect to the longitudinal axis, slightly inclined, so that there is a shingle-like, staggered structure. By substantially axial cooling holes 16, a laminar inflow of compressor discharge air 12 takes place. In addition, essentially radial cooling holes 17 can be provided. The respective upstream combustion chamber segment comprises a lip 18 on the cooling ring.

By additional damping openings 19 a air is introduced for damping, wherein the damper volume is formed by the distance 19 b to the housing 2 or 3 ..

The embodiment of FIG. 4 differs in that no radial cooling holes 17 are provided, but several rows of substantially axial cooling holes are arranged radially staggered.

In the embodiment of FIG. 5 (in connection with the embodiment variants of FIG. 6) non-cylindrical damping openings are shown, which can have very different cross-sections, both over their axial length and overall.

The exemplary embodiments of FIGS. 7 to 9 each show a two-layer structure of the combustion chamber wall. In this case, a damper housing 20 is additionally provided, which encloses a steamer volume 21. The damper volume 21 may be divided in the circumferential direction and / or be filled with additional material (see above). The embodiments of FIGS. 8 and 9 each show that one end of the damper housing is fixedly connected (22), while the other region has a displaceable or displaceable separation point 23. As a result, thermal length expansions can be compensated.

10 and 11 show two embodiments with a single-layer and two-layer structure with arrangement of the damper near the heat release zone of the combustion chamber.

LIST OF REFERENCE NUMBERS

1

Kompressorauslassschaufeln

2

Combustion chamber outer housing

3

Combustion chamber inner housing

4

Burner with arm and head (diffusion flame)

5

bulkhead

6

Combustion chamber wall with cooling rings 6a

7

Turbine inlet vanes

8th

inflow bore

9

damper wall

10

combustion chamber wall

11

Damping and cooling holes

12

Compressor discharge air

13

Flame and flue gas from the lean burner

14

Damper gap between damper wall 9 and combustion chamber wall 10th

15

16

essentially axial cooling holes

17

essentially radial cooling holes

18

Lip on the cooling ring

19a

damping openings

19b

damper space

19c

non-cylindrical damping openings

20

Damper housing between two cooling rings

21

Damper volume (possibly divided in the circumferential direction)

22

solid joint (e.g., welded or bolted to flange)

23

movable separation point (sliding seat with or without seal)

24

lean burner

Claims (15)

1. Gas turbine combustion chamber wall for a lean burning gas turbine combustor having a combustion chamber housing (2, 3) and several in the combustion chamber housing (2, 3) are arranged, a combustion chamber wall (10) forming the combustion chamber segments which each have axial and / or radial cooling holes (16, 17 ) are supplied with cooling air with a film cooling, wherein the cooling holes (16, 17) are spaced from each other in the axial direction and wherein in this area damping openings (19 a) are provided for the introduction of air. 3. gas turbine combustion chamber wall according to claim 1, characterized in that the combustion chamber elements are each annular and frusto-conical. 3. gas turbine combustion chamber wall according to claim 2, characterized in that the combustion chamber elements are arranged overlapping each other at their edge regions. 4. gas turbine combustion chamber wall according to one of claims 1 to 3, characterized in that the combustion chamber segments are disposed near the maximum heat release zone of the gas turbine combustor. 5. gas turbine combustion chamber wall according to one of claims 1 to 3, characterized in that the combustion chamber segments are arranged centrally between the burner (24) and turbine inlet blades (7). 6. gas turbine combustion chamber wall according to one of claims 1 to 5, characterized in that the combustion chamber segments are formed single-walled. 7. gas turbine combustion chamber wall according to one of claims 1 to 5, characterized in that the combustion chamber segments are double-walled with a radially outer, a damper volume (21) forming damper housing (20) are formed. 8. gas turbine combustion chamber wall according to claim 7, characterized in that the damper housing (20) is fixedly arranged on the combustion chamber segment. 9. gas turbine combustion chamber wall according to claim 7, characterized in that the damper housing (20) is fixedly disposed at one end and slidably disposed at its other end to the combustion chamber segment. 10. gas turbine combustion chamber wall according to one of claims 7 to 9, characterized in that the circumferential damper volume (21) of the damper housing (20) is divided into individual chambers. 11. gas turbine combustion chamber wall according to one of claims 7 to 10, characterized in that the circumferential damper volume (21) of the damper housing (20) is at least partially filled with an air-permeable material. 12. gas turbine combustion chamber wall according to one of claims 1 to 11, characterized in that it is made of metal. 13. gas turbine combustion chamber wall according to one of claims 1 to 11, characterized in that it is made of ceramic. 14 gas turbine combustion chamber wall according to one of claims 1 to 11, characterized in that it is made of CMC. 15. gas turbine combustion chamber wall according to one of claims 1 to 14, characterized in that between the damping openings (19 a), which lead substantially perpendicularly through the combustion chamber wall (10), effusion cooling holes are arranged at a shallow angle to the surface of the combustion chamber wall (10).

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