EP2049840B1 - Combustion chamber of a combustion installation - Google Patents

Description

Technical area

The invention relates to a combustion chamber of a combustion plant, in particular a gas turbine, with a heat shield having at least two segments.

State of the art

Usually combustion chambers of a combustion system, such as a gas turbine, equipped with a so-called heat shield, which protects an underlying support structure from direct contact with a hot gas stream. Depending on the position in the combustion chamber or with respect to the hot gas flow while the heat shield or individual segments thereof are exposed to a different temperature load.

From the EP 1 143 109 B1 For example, a nozzle segment for use in a gas turbine is known, which comprises a substantially radially between a nozzle wall and a cover extending side wall and a Having spaced from the nozzle wall, inwardly facing flange. The inwardly facing flange defines, together with the nozzle wall and the sidewall, an undercut area, wherein a plurality of openings leading through the inwardly facing flange are provided to flow cooling medium for impingement cooling of the sidewall into the undercut area. As a result, a substantially uniform cooling of the heat shield or the side wall is achieved. As described above, the heat shield, depending on the situation in the combustion chamber, exposed to a different high temperature load, which makes a locally different cooling required for optimum cooling.
The EP 1 477 737 A1 describes a gas turbine with a combustion chamber and a device for applying liner elements to a support means to form the inner wall of the combustion chamber. The carrying device has both an inner and an outer carrying structure, which respectively carry inner and outer liner elements. The liner elements are attached via screw to the corresponding inner or outer support structure. In particular, the liner elements have a flange structure which is fixed directly on the inner or outer support structure. Each liner element also has an edge region which engages behind the flange region, wherein an open gap is formed between the edges of adjacent liner elements.

Presentation of the invention

This is where the invention starts. The invention, as characterized in the claims, deals with the problem of providing for a combustion chamber of the type mentioned in an improved embodiment, which is characterized in particular by a locally adapted cooling of a heat shield.

This problem is solved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea, a heat shield having at least two segments with internal cooling channels in such a way that a locally different cooling within a segment is possible. In general, each segment has a lining element facing a combustion chamber and a holding device, wherein the Liner element is directly exposed to the hot gas flow, and is attached via a support member to a support structure. In contrast, the holding device, the liner element and the support element are fixed to the support structure. On the edge side, each liner element has an edge region which engages behind a flange region formed by the holding device. In this case, the individual segments are arranged side by side so that between the edges of two adjacent liner elements to the combustion chamber open gap for thermal expansion remains, but in which hot gas can penetrate. Therefore, it is provided in the combustion chamber according to the invention that the holding device forms, together with the support element, a first cooling channel, in which cooling gas flows to cool the liner element. In order to cool the edge regions of the liner elements facing the gap, the holding device has passage openings in the region of its flange region, through which cooling gas flows from the first cooling channel to the edge region to be cooled and, depending on the design of the through openings, allows locally reinforced or reduced cooling of the edge region. Since the liner elements in the region of the gap do not extend completely to the support element or to the support structure, hot gas which has penetrated into the gap can lead to impairment or damage to the support elements or the support structure. To counteract this, the passage openings are provided, which allow targeted guidance of cooling gas from the first cooling channel to the edge region to be cooled and thereby create a need-based, locally limited, cooling. The inventive, locally adapted cooling, damage or impairment of the support elements or the support structure can be avoided and thereby the life of the combustion chamber can be increased. At the same time reduces maintenance, which can be achieved a reduction in operating costs.

According to an advantageous embodiment of the solution according to the invention, a distance between two passage openings and / or a diameter of the passage openings is adapted to a local cooling requirement. With a high cooling requirement, it is therefore conceivable that a distance between two adjacent passage openings is chosen to be relatively small and / or a diameter of the passage openings is chosen to be relatively large, while for a rather small cooling requirement, the distance between two passage openings larger or the diameter of the passage openings chosen smaller can be. This customization allows demand-based cooling of locally different temperature-loaded areas and thereby also an improvement in the efficiency of the turbine, since there are no over-cooled areas, which cool the hot gas flow unnecessarily.
Particularly advantageous is an embodiment in which an inner liner element is provided between the support structure and the liner element, which forms a second cooling channel together with the support structure, or in which the liner element forms a third cooling channel together with the inner liner element. Such a splitting into a plurality of cooling channels within the heat shield allows an even more precise control of the cooling of the heat shield, wherein the cooling gas first flows through the areas to be cooled more strongly and then, after appropriate heating, cools the less to be cooled areas. This allows a particularly effective and also adapted to the respective required cooling cooling done. The pressure in the second cooling channel may be greater than in the first cooling channel and in the first cooling channel greater than in the third cooling channel. By this pressure gradient, a controllable cooling flow can be generated, which independently due to the pressure difference flows through in each case to be cooled areas and thus a complex control of the cooling currents is unnecessary. The pressure difference between the individual cooling channels can be controlled via a flow cross-section of the connecting channels connecting the individual channels, whereby at the same time influence on the flow velocity can be taken.

Other important features and advantages of the rotor according to the invention will become apparent from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Fig. 1

eine Schnittdarstellung durch ein erfindungsgemäßes Hitzeschutzschild einer Brennkammer,

Fig. 2

eine mögliche Anordnung von Durchgangsöffnungen zwischen einem ersten Kühlkanal und einem zu kühlenden Randbereich,

Fig. 3a - 3c

unterschiedliche Anordnungen von Durchgangsöffnungen zwischen dem ersten Kühlkanal und dem zu kühlenden Randbereich.

They show, in each case schematically,

Fig. 1

a sectional view through an inventive heat shield a combustion chamber,

Fig. 2

a possible arrangement of passage openings between a first cooling channel and an edge region to be cooled,

Fig. 3a - 3c

different arrangements of through holes between the first cooling channel and the edge region to be cooled.

Ways to carry out the invention

Corresponding Fig. 1 is a sectional view through a combustion chamber wall of a combustion system shown, in particular a gas turbine, with a heat shield 1, which has at least two juxtaposed segments 2 and 2 '. Each of the two segments 2 and 2 'moreover has a liner element 4 facing a combustion chamber 3 and a holding device 5. The liner element 4 is formed from a heat-insensitive material, since it is in direct contact with existing in the combustion chamber 3 hot gases. The two liner elements 4 and 4 'are fixed via a support element 6 to a support structure 7, wherein the support device 5 defines both the liner element 4 and the support element 6 on the support structure 7. In this case, the liner element 4 is fastened to the holding device 5 by means of an edge region 8 formed on the liner element 4, which engages behind an undercut-like manner by means of a flange region 9 formed by the holding device 5. On a side facing away from the linerelementseitigen edge region 8 is carried out in the same way a fixing of an inner liner member 13 via the holding device 5 on the support member. 6

Of the Fig. 1 It can also be seen that between the two adjacent segments 2 and 2 ', in particular between the two adjacent liner elements 4 and 4' to the combustion chamber 3 open gap 10 for receiving thermal expansion of the liner elements 4, 4 'remains, in which but also Hot gas can penetrate and leads there to a high temperature load. In particular, it is also conceivable that the hot gas flowing into the gap 10 act on a gap bottom almost directly on the support element 6 and this can affect in terms of its function. To avoid such an impairment by flowing into the gap 10 hot gas or to be able to reduce at least, the invention proposes that the holding device 5 together with the support element 6 forms a first cooling channel 11 and passage openings 12 has (see also Fig. 2 ), which are directed towards the edge region 8 to be cooled, so that cooling gas, in particular cooling air, can flow from the first cooling channel 11 to the edge region 8 to be cooled and cool it. The passage openings 12 are provided in the region of the flange area 9 of the holding device 5.

In order to be able to adapt a cooling performance required for the cooling stream impact required for cooling, a distance between two passage openings 12 and / or a diameter of the passage openings 12 can be varied. Such a variation is according to Fig. 2 shown, from which it can be seen that the through holes 12 have a significantly smaller diameter or cross section in a left area than in a right area. In this way, with a uniform flow through the through-openings 12 in the right-hand region, a higher cooling capacity or a higher cooling-gas outrun from the through-openings 12 can be achieved than in the left-hand region. Can the required cooling capacity to the cooling needs with a single in Fig. 2 shown series of through holes 12 are not achieved, it is conceivable that a plurality of substantially parallel to the gap 10 extending rows of through holes 12 are provided. A second row is according to Fig. 2 indicated.

Again Fig. 1 can be seen further, an inner liner member 13 is provided between the support structure 7 and the liner member 4, which forms a second cooling channel 14 together with the support structure 7. On a side facing away from the second cooling channel 14, the inner liner element 13 together with the liner element 4 forms a third cooling channel 15. The individual cooling channels 11, 14 and 15 to connect with each other, a connecting channel 16 is provided between the first cooling channel 11 and the second cooling channel 14. Between the first cooling channel 11 and the third cooling channel 15, in turn, the through openings 12 are arranged, which provide a connection between the two channels.

In order to be able to generate as continuous a flow of coolant as possible in the individual channels 11, 14 and 15, it can be provided that the pressure in the second cooling channel 14 is greater than in the first cooling channel 11, so that preferably continuously cooling gas from the second cooling channel 14 via the Connecting channel 16 flows into the first cooling channel 11. In addition, the pressure in the first cooling channel 11 should preferably be greater than in the third cooling channel 15, so that here, too, a continuous flow of cooling gas from the first cooling channel 11 via the through holes 12 in the third cooling channel 15 takes place.

The arrangement of the individual cooling channels 11, 14 and 15 and the pressure distribution in the same, a targeted coolant flow can be generated, which is adapted to a local cooling demand. Thus, in the second cooling channel 14, the cooling gas is still relatively cold and thereby cools the inner liner element 13. After the passage of the cooling gas through the connecting channel 16 in the first cooling channel 11 and the holding means 5 is cooled by the cooling gas stream. Furthermore, the cooling gas flow flows through the passage openings 12 to the linerelementseitigen edge region 8 and cools it, before it continues through the third cooling channel 15, which is disposed between the inner liner member 13 and the liner member 4 and there contributes to the cooling of the liner member 4. It is clear that the cooling gas, starting from the second cooling channel 14 via the first cooling channel 11 to the third cooling channel 14 is constantly heated, so that a sufficient cooling capacity in the third cooling channel 15 by arrangement is favored by so-called cooling fins 17. The cooling ribs 17 are arranged on a side facing away from the combustion chamber 3 of the liner element 4 and protrude into the third cooling channel 15 inside. The enlargement of the surface thus results in an improved cooling effect, as would be possible in one embodiment without cooling ribs 17.

In Fig. 3 Now, several conceivable embodiments of the flange portion 9 of the holding device 5 are shown, wherein this in Fig. 3a has three rows of through holes 12 and thereby achieves a particularly high cooling effect on the facing edge region 8 of the liner element 4. Compared to Fig. 3a has the flange portion 9 of the holding device 5 according to Fig. 3b only two rows of through holes 12, whereby the force acting on the edge region 8 cooling capacity is reduced. The cooling capacity can be reduced again by the flange area 9 of the holding device 5, as in FIG Fig. 3c shown, only a series of through holes 12 has. The three different embodiments already show that, depending on the embodiment of the flange region 9 of the holding device 5 or depending on the arrangement of the through holes 12, a different, individually adapted to a cooling demand cooling capacity can be achieved. The different rows of through holes 12 extend according to the Fig. 3a to 3c essentially perpendicular to the image plane.

LIST OF REFERENCE NUMBERS

1

Heat shield

2

segments

3

combustion chamber

4

liner element

5

holder

6

supporting member

7

supporting structure

8th

Edge region of the liner element 4

9

Flange area of the holding device 5

10

Gap between two liner elements 4

11

first cooling channel

12

Through opening

13

inner liner element

14

second cooling channel

15

third cooling channel

16

connecting channel

17

cooling fin

Claims (9)

1. Combustion chamber of a combustion installation, in particular a gas turbine, with a heat shield (1) having at least two segments (2, 2'),

   - wherein each segment (2, 2') has a liner element (4, 4') facing a combustion space (3), and a holding device (5, 5'),

   - wherein the liner element (4, 4') is attached to a supporting structure (7) via a supporting element (6), and wherein the holding device (5) fixes the liner element (4, 4') and the supporting element (6) to the supporting structure (7),

   - wherein the liner element (4, 4') has an edge region (8, 8') which engages behind a flange region (9, 9') formed by the holding device (5, 5'),

   - wherein a gap (10) open towards the combustion chamber remains between the edges of two adjacent liner elements (4, 4'),
   characterised in that

   - the holding device (5) together with the supporting element (6) forms a first cooling channel (11), and that to cool the edge regions (8, 8') of the liner elements (4, 4') facing the gap (10), the holding device (5, 5') in the area of its flange region (9, 9') has passage openings (12, 12') through which cooling gas flows from the first cooling channel (11, 11') to the edge region (8, 8') to be cooled.
2. Combustion chamber according to claim 1, characterised in that a distance between two passage openings (12) and/or a diameter of the passage openings (12) is adapted to the local cooling requirements.
3. Combustion chamber according to claim 1 or 2, characterised in that between the supporting structure (7) and the liner element (4, 4'), an inner liner element (13, 13') is provided which, together with the supporting structure (7), forms a second cooling channel (14).
4. Combustion chamber according to claim 3, characterised in that the liner element (4, 4') together with the inner liner element (13, 13') forms a third cooling channel (15, 15').
5. Combustion chamber according to claim 3 or 4, characterised in that at least one connecting channel (16, 16') is provided between the first and the second cooling channels (11, 11', 14, 14').
6. Combustion chamber according to any of claims 1 to 5, characterised in that the holding device (5, 5') comprises at least one row of passage openings (12) running substantially parallel to the gap (10).
7. Combustion chamber according to any of claims 4 to 6, characterised in that on its side facing away from the combustion space (3), the liner element (4, 4') has cooling ribs (17, 17') which protrude into the third cooling channel.
8. Combustion chamber according to any of claims 3 to 7, characterised in that the inner liner element (13, 13') is attached to the supporting element (6) via the holding device (5, 5').
9. Combustion installation, in particular a gas turbine, with a combustion chamber according to at least one of claims 1 to 8.

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