EP2179143A2

EP2179143A2 - Gas turbine installation

Info

Publication number: EP2179143A2
Application number: EP08786927A
Authority: EP
Inventors: Ulrich Steiger; Willy Heinz Hofmann
Original assignee: Alstom Technology AG
Current assignee: General Electric Technology GmbH
Priority date: 2007-08-06
Filing date: 2008-08-06
Publication date: 2010-04-28
Anticipated expiration: 2028-08-06
Also published as: EP2179143B1; ATE497087T1; US20100146988A1; DE502008002497D1; WO2009019282A3; WO2009019282A2; US8132417B2

Abstract

The invention relates to a gas turbine installation (1) in particular for a power station, comprising a combustion chamber (2) which radially bounds a combustion chamber gas path (9) at least in an annular outlet area (6) with a chamber inner wall (7) and with a chamber outer wall (8), a turbine (3), which radially bounds a turbine gas path (13) in a stationary, annular inlet area (10) with a turbine inner wall (11) and with a turbine outer wall (12), a gap (4; 16, 17) which is provided radially on the inside and/or radially on the outside axially between the combustion chamber (2) and the turbine (3) and at which the inner and/or outer chamber wall (7, 8) and the inner and/or outer turbine wall (11, 12) end/ends, and a cooling gas supply (5) which introduces a cooling gas through the gap into the turbine gas path (13) and/or into the combustion chamber gas path (9). An end section (21, 22, 23, 24), which is adjacent to the gap of the respective turbine wall (11, 12) and/or of the respective chamber wall (7, 8) is shaped radially on the inside and/or radially on the outside such that positive steps (a, c), in the case of which the respective downstream wall projects with respect to the respective upstream wall (7, 8) radially into the respective gas path (9, 13), and negative steps (b, d), in the case of which the respective upstream wall projects radially into the respective gas path (9, 13) with respect to the respective downstream wall, alternates in the circumferential direction on the gap.

Description

Gas turbine plant

Technical area

The present invention relates to a gas turbine plant, in particular for a power plant.

State of the art

Such a gas turbine plant usually comprises a combustion chamber which radially delimits a combustion gas path at least in an annular outlet region with a chamber inner wall and with a chamber outer wall. Furthermore, such a gas turbine plant usually comprises a turbine which radially delimits a turbine gas path at least in a stationary annular inlet area with a turbine inner wall and with a turbine outer wall. In order to avoid excessive component voltages during transient operating conditions of the gas turbine plant, the gas turbine plant can also be provided with a radially inner and / or radially outer axially between the

Combustion chamber and the turbine running gap be provided, at which the inner and / or outer chamber wall and the inner and / or outer turbine wall end. To avoid an entry of hot working gases in this gap may also expediently a cooling gas supply be provided, which introduces a cooling gas into the turbine gas path and / or in the combustion gas path via the gap.

However, the supply of cooling gas to the working gas of the gas turbine plant directly reduces their performance and their efficiency. It is therefore desirable to use as little as possible cooling gas.

Gas turbines are known from US Pat. No. 6,283,713 B1 and GB 2,281,356 A, in which the radially inner platforms of the individual guide vanes are contoured at least in one row of guide vanes so that a wave-shaped surface course results in the circumferential direction. As a result, the static pressure in the working gas can be influenced to the effect that in the ideal case immediately downstream of the guide vane row sets a substantially constant static pressure.

A gas turbine is known from US 2006/0034689 A1, in which a row of guide vanes has on its inflow side a multiplicity of flow guide elements projecting radially into the gas path. With the aid of these flow guide elements, a leakage flow flowing around the blade tips upstream of the rotor blades can be reduced or deflected in the axial direction so as to increase the efficiency of the gas turbine.

Presentation of the invention

The invention, as characterized in the claims, deals with the problem of providing for a gas turbine plant of the type mentioned in an improved embodiment, which is characterized in particular by an increased efficiency. 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 of achieving a pressure distribution in the gap influencing the flow of cooling gas by a specific positioning of circumferentially alternating positive and negative steps along the gap. This pressure distribution can be specifically set up so that areas with increased cooling demand are subjected to a higher cooling gas flow than areas with a smaller cooling demand. As a result, the total amount of cooling gas required can be reduced, which ultimately increases the efficiency of the gas turbine plant.

In order to be able to realize the alternating positive and negative steps in the circumferential direction, the combustion chamber wall or the turbine wall is correspondingly contoured in the end section adjoining the gap.

The circumferentially varying contours of the respective chamber wall and the respective turbine wall in the region of the radially inner gap and / or in the region of the radially outer gap can be selected and designed on the basis of different criteria. For example, in order to design the alternately arranged in the circumferential direction arrangement of positive and negative steps at the gap in the circumferential direction distribution of alternating pressure sides and suction sides of

Guide vanes are used in a stationary inlet area arranged Leitschaufelreihe. This guide blade row arranged in the entry region is usually the so-called "first row of guide blades." The pressure sides and suction sides of the guide blades bring about this Also upstream to the gap varying pressures in the circumferential direction, which may affect the flow of cooling gas in the gap. By appropriate consideration of the pressure sides and suction sides in the dimensioning and positioning of the steps along the gap, these adverse influences can be reduced.

Furthermore, it is additionally or alternatively possible to take into account a dependency of bow-shafts of guide vanes of a guide blade row arranged in the stationary inlet region, which arise during operation of the gas turbine plant and are spaced successively in the circumferential direction. Even such bow waves can spread to the gap and can influence the pressure distribution there. By taking into account this bow wave distribution, their negative effects on the cooling gas flow can be reduced.

Additionally or alternatively, during the design of the steps at the gap, a pressure distribution which varies in the circumferential direction during operation of the gas turbine plant at or in the exit region of the combustion chamber can also be taken into account. It has been found that in the exit region of the combustion chamber in the circumferential direction different

Flow rates or varying pressures may occur. The pressure distribution or velocity distribution which arises during steady-state operation of the gas turbine can be stationary and could, for example, be due to the burner arranged distributed in the circumferential direction in a multi-burner combustion chamber. The pressures varying in the circumferential direction in the exit region of the combustion chamber also influence the flow of cooling gas through the gap. By appropriate consideration of the pressure distribution in the outlet region of the combustion chamber, the disadvantageous influence on the cooling gas flow can be reduced. Further important features and advantages of the gas turbine plant according to the invention will become apparent from the subclaims, from the drawing and from the associated description of the figures with reference to the drawing.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description.

The only Fig. 1 shows a greatly simplified axial section of a gas turbine plant in the region of a gap between a combustion chamber and a turbine.

Ways to carry out the invention

1, a gas turbine plant 1, which is preferably used in a power plant, ie stationary, a combustion chamber 2 and a turbine 3, between which an axial gap 4 is arranged. Furthermore, a cooling gas supply 5 indicated by arrows is provided. As a reference for the radial and axial orientation is entered in Fig. 1, a longitudinal center axis or axis of rotation X.

The combustion chamber 2 has, at least in an annular outlet region 6, a chamber inner wall 7 and a chamber outer wall 8, which together radially bound a combustion chamber gas path 9 indicated by an arrow. The turbine 3 has, at least in a stationary, ie stator, annular inlet region 10, a turbine inner wall 1 1 and a turbine outer wall 12, which together define a radially indicated by an arrow turbine gas path 13. Furthermore, the turbine 3 in the stationary inlet region 10 can usually have a row of guide vanes 14 with a plurality of guide vanes 15 which are adjacent in the circumferential direction. Since this vane row 14 is the first row of blades impinged by the hot gases of the combustion chamber 2, it is usually also referred to as the first row of stator blades 14.

The gap 4 consists in the example shown of a radially inner gap 16 and a radially outer gap 17. The radially inner gap 16 is referred to below as the inner gap 16 or inner gap 16. Accordingly, in the following, the radially outer gap 17 is also referred to as the outer gap 17 or outer gap 17. At the inner gap 16, the chamber inner wall 7 and the turbine inner wall 1 1 each end axially. At the outer gap 17, the chamber outer wall 8 and the turbine outer wall 12 each end axially.

The cooling gas feed 5 is designed such that it introduces a cooling gas into the turbine gas path 13 or into the combustion gas path 9 via the gap 4 or via the respective sub-gap 16 or 17. The introduction of cooling gas into the gap 4 serves to avoid the entry of hot gases from the combustion gas path 9 or from the turbine gas path 13 through the gap 4 in the areas behind the respective chamber walls 7, 8 and turbine walls 11, 12th

The turbine walls 7, 8 may be formed, for example, by heat shield elements or by so-called liners 18. The turbine walls 11, 12 can by platforms 19 and 20, which are formed on the respective blade root radially outside and inside, be formed.

In order to reduce the cooling gas requirement, according to the invention at the gap 4 radially inwardly and / or radially outwardly, ie at the inner gap 16 and / or the outer gap 17 in the circumferential direction alternating positive and negative steps are formed in the axial direction. If we achieve this by means of a corresponding shaping of an end section of the respective turbine wall 11, 12 or of the respective chamber wall 7, 8 adjoining the respective gap 4 or 16 or 17. An end section of the chamber inner wall 7 is designated 21, an end section of the chamber outer wall 8 is designated 22, an end portion of the turbine inner wall 1 1 is denoted by 23 and an end portion of the turbine outer wall 12 is denoted by 24. Regions of the end portions 21 to 24 lying in the sectional plane are shown by solid lines, while offset portions of the end portions 21 to 24 thereof are shown by broken lines. Furthermore, the named stages are denoted by the lowercase letters a to d. Here, a denotes a positive step formed on the inner gap 16, while b denotes a negative step formed on the inner gap 16. A positive stage at the outer gap 17 is denoted by c, while d denotes a negative step at the outer gap 17. A positive stage a, c is present when the respective downstream wall 1 1, 12 protrudes radially into the respective gas path 9, 13 with respect to the respective upstream wall 7, 8. In contrast, there is a negative stage b, d, when the respective upstream wall 7, 8 projecting radially projecting into the respective gas path 9, 13 with respect to the respective downstream wall 1 1, 12.

In principle, it may be sufficient if only at the inner gap 16 or only at the outer gap 17, the sequence alternating positive and positive in the circumferential direction negative stages a, b and c, d is realized. Shown, however, is the variant in which both radially inward and radially outward at the gap 4, the sequence of positive and negative steps a to d alternating in the circumferential direction is realized.

At the radially inner gap 16, the positive stage a can be realized, for example, that the combustion chamber inner wall 7 in the adjacent to the gap 4 and the inner gap 16 end portion 21 in the positive stage a relative to the in the circumferential direction on both sides of the positive Stage a adjacent areas radially offset inwardly. The inner positive stage a can thus be e.g. be realized only by contouring the chamber inner wall 7 in the end portion 21.

Additionally or alternatively, the inner positive stage a can be realized in that the turbine inner wall 1 1 extends in the associated end section 23 in the region of the positive step a radially outwardly offset relative to the areas adjacent to the positive step a in the circumferential direction. In this way, the positive stage a can be realized in principle only by a corresponding contouring of the turbine inner wall 11 in the end portion 23.

However, preference is given to an embodiment in which both a varying contour on the combustion chamber inner wall 7 in the region of the end portion 21 and a varying contour of the turbine inner wall 1 1 in the region of the end portion 23 cooperate to form the desired positive stage a at the inner gap 16.

For the formed on the inner gap 16 negative stage b apply corresponding configuration options. This negative step b can be realized in that the burner inner wall 7 in which the inner gap 16 adjacent end portion in the region of the negative stage b relative to the circumferentially on both sides of the negative step b adjacent areas radially offset outwardly extends. The negative step b can also be realized in that the turbine inner wall 1 1 extends radially inwardly in the region adjacent to the inner gap 16 in the region of negative steps b relative to the regions adjacent to the negative step b in the circumferential direction. Likewise, the negative stage b can be realized by a combination of the above measures.

The same now applies to the outer gap 17. In order to realize there the positive stage c, the combustion chamber outer wall 8 in the adjoining the outer gap 17 end portion 22 in the positive stage c relative to the circumferentially on both sides of the positive stage c adjacent areas offset radially outward. Likewise, the positive stage c at the outer gap 17 can be realized in that the turbine outer wall 12 in the adjoining the outer gap 17 end portion 24 in the positive stage c relative to the circumferentially on both sides of the positive stage c adjacent areas radially inwardly offset runs. However, preference is given to a combination of the two measures mentioned above.

Similarly, at the outer gap 17, the negative step d be realized, for example, that the combustion chamber outer wall 8 in the adjacent to the outer gap 17 end portion 22 in the negative stage d relative to the circumferentially on both sides of the negative step d adjacent areas radially inwardly staggered. Similarly, the negative step d can be realized at the outer gap 17 that the turbine outer wall 12 in the adjoining the outer gap 17 end portion 24 in the negative stage d relative to the circumferentially on both sides of the negative step d adjacent areas offset radially outwards. It is clear that a combination of the two above measures is also preferably realized in order to form the respective negative step d at the outer gap 17.

In Fig. 1, the deviations of the contour on the respective walls 7, 8, 1 1, 12 are exaggerated in order to improve their visibility for the present description.

In the circumferential direction can thus on the respective wall 7, 8, 1 1, 12 in the region of the respective end portion 21, 22, 23, 24 with respect to the respective

Gas paths 9, 13 alternate convex and concave areas, but gradually merge into each other.

For the design, in particular for the dimensioning and positioning of the positive and negative stages a, b, c, d, there are different possibilities, which are alternatively or completely or partially cumulatively applicable. In the following, some criteria are explained in more detail by way of example, which can be implemented separately or in total or in any combination in the gas turbine plant 1 according to the invention.

For example, the arrangement of positive and negative stages a, b, c, d, which varies in the circumferential direction, may be formed as a function of a cooling requirement which occurs during operation of the gas turbine plant 1 at the respective gap 4 or at the inner gap 16 and / or at the outer gap 17 and especially in the circumferential direction can vary. It is clear that this cooling demand curve is present in the gap 16, 17 at a stationary operating state of the gas turbine plant 1 is substantially stationary. In order to increase the cooling gas flow in a peripheral segment that has an increased cooling requirement, a negative step b, d can be provided in this area. Through which in the gap 4 Such a negative stage b, d-adjusting pressure conditions can be targeted realize a pressure drop and thus an acceleration or a higher flow velocity for the cooling gas. In contrast, in circumferential segments in which a reduced cooling gas flow is sufficient, a positive step a, c can be realized, which leads to an increase in pressure and thus to a deceleration or to a reduced flow velocity in the cooling gas.

In the operation of the gas turbine plant 1, other dynamic effects occur in the region of the gap 4, which can influence the pressure progression in the circumferential direction of the gap 4 nonuniformly. These boundary conditions can be taken into account when designing the step distribution along the gap 4 accordingly.

For example, for the circumferentially alternating arrangement of positive and negative stages a, b, c, d, a distribution in the circumferential direction of pressure sides and suction sides of the guide vanes 15 of the first row of guide vanes 14 can be taken into account. These pressure sides and suction sides alternate in the circumferential direction and result from the profiling of the guide vanes 15. In the circumferential direction alternating pressure sides and suction sides influence the pressure in the respective gas path 9, 13 also in the counterflow direction and at least up to the gap 4 a corresponding consideration of this distribution of the pressure sides and suction sides in the design of the steps at the gap 4, their influence can be reduced accordingly or used to set the desired cooling gas distribution.

During operation of the gas turbine plant 1, moreover, at the leading edges of the guide vanes 15 of the first guide blade row 14, so-called Form bow waves that propagate against the flow direction and can reach at least until the gap 4. Such bow waves also lead to a stationary influencing of the pressure distribution in the circumferential direction in the gap 4. By a corresponding consideration of the bow wave distribution in the design of stages a to d, this effect can be reduced or used for the desired cooling.

Furthermore, during operation of the combustion chamber 2, flow conditions may arise in its gas path 9, which generate flow velocities or varying pressures varying at least in the outlet region 6 in the circumferential direction. In the process, this pressure distribution varying in the circumferential direction can be stationary in a stationary operating state of the gas turbine plant 1. Accordingly, here too, the influence of a pressure distribution generated in the gap 4 by the operation of the combustion chamber 2 can be reduced or utilized for the desired cooling gas distribution by suitable design of stages a to d.

The measures proposed according to the invention, which can be implemented separately or in any cumulative form, are characterized by the fact that a significant influence of the cooling gas flow in the gap 4 can be realized without appreciably increasing the surface of the combustion chamber 2 or the turbine 3 exposed to the hot working gases becomes. An enlarged surface, as it is realized for example by projecting into the gas path Strömungsleitelemente simultaneously increases the cooling demand for the flow guide and is disadvantageous in this respect.

LIST OF REFERENCE NUMBERS

1 gas turbine plant 2 combustion chamber

3 turbine

4 gap

5 cooling gas supply

6 exit area of the combustion chamber 7 combustion chamber inner wall

8 combustion chamber outer wall

9 combustion chamber gas path

10 inlet area of the turbine

1 1 Turbine inner wall 12 Turbinenaußenwand

13 turbine gas path

14 vane row

15 vane

16 inner gap 17 outer gap

18 heat shield element

19 Outer platform of the turbine vane

20 inner platform of turbine vane

21 end section of 7 22 end section of 8

23 end of 11 24 final section of 12

25 leading edge of the guide

a positive step at 16 b negative step at 16

C positive stage at 17 d negative stage at 17

X longitudinal center axis / rotation axis

Claims

claims

1. gas turbine plant, in particular for a power plant, - with a combustion chamber (2) which at least in an annular outlet region (6) with a chamber inner wall (7) and with a chamber outer wall (8) radially bounds a combustion gas path (9),

- With a turbine (3) which at least in a stationary, annular inlet region (10) with a turbine inner wall (1 1) and with a turbine outer wall (12) radially a turbine gas path (13) radially,

- With a radially inner and / or radially outer axially between the combustion chamber (2) and the turbine (3) existing gap (4; 16, 17), to which the inner and / or outer chamber wall (7, 8) and the inner and / or outer turbine wall (1 1, 12) ends, - with a cooling gas supply (5), which introduces via the gap (4; 16, 17) a cooling gas in the turbine gas path (13) and / or in the combustion gas path (9) .

- wherein radially on the inside and / or radially outside of the gap (4; 16, 17) adjacent end portion (21, 22, 23, 24) of the respective turbine wall (1 1, 12) and / or the respective chamber wall (7, 8 ) is shaped so that in the circumferential direction at the gap (4; 16, 17) positive steps (a, c), in which the respective downstream wall (1 1, 12) relative to the respective upstream wall (7, 8) protruding radially into the respective gas path (9, 13), and alternating negative stages (b, d), in which the respective upstream wall (7, 8) opposite to the respective downstream wall (1 1, 12) in the respective Gas path (9, 13) projecting radially projecting.

2. Gas turbine plant according to claim 1, characterized in that the alternately in the circumferential direction arrangement of positive and negative stages (a, b, c, d) depending on a in operation of the gas turbine plant (1) at the gap (4; 16, 17) adjusting is selected in the circumferential direction varying cooling demand.

3. Gas turbine plant according to claim 1 or 2, characterized in that the alternately in the circumferential direction arrangement of positive and negative stages (a, b, c, d) in dependence of a present in the circumferential direction distribution of alternating pressure sides and suction sides of vanes (15) of a in the stationary inlet region (10) arranged (first) guide vane row (14) is selected.

4. Gas turbine plant according to one of claims 1 to 3, characterized in that the alternately in the circumferential direction arrangement of positive and negative stages (a, b, c, d) depending on the operation of the gas turbine plant (1) resulting in the circumferential direction spaced apart following, upstream propagating bow waves of vanes (15) of a (10) arranged in the stationary inlet region (first) row of guide vanes (14) is selected.

5. Gas turbine arrangement according to one of claims 1 to 4, characterized in that the alternately in the circumferential direction arrangement of positive and negative stages (a, b, c, d) in response to a during operation of the gas turbine plant (1) at or in the exit region (6 ) of the combustion chamber (2) adjusting, varying in the circumferential direction pressure distribution is selected.

6. gas turbine plant according to one of claims 1 to 5, characterized in that at the gap (4; 16) radially inwardly a positive step (a) is formed by the fact that the combustion chamber inner wall (7) in which at the gap (4; 16) adjacent end portion (21) in the region of the positive step (a) relative to the circumferentially on both sides of the positive step (a) adjacent areas radially inwardly offset extends and / or that the turbine inner wall (11) in which the gap (4; 16) adjoining end portion (23) in the region of the positive step (a) relative to the circumferentially on both sides of the positive step (a) adjacent areas radially offset outwardly.

7. gas turbine plant according to one of claims 1 to 6, characterized in that at the gap (4; 16) radially inwardly a negative step (b) is formed by the fact that the combustion chamber inner wall (7) in which at the gap (4; 16) adjacent end portion (6) in the region of the negative step (b) relative to the circumferentially on both sides of the negative step (b) adjacent areas radially outwardly offset and / or that the turbine inner wall (11) in which the gap (4; 16) adjacent the end portion (23) in the region of the negative step (b) is offset radially inwardly relative to the regions adjacent to the negative step (b) in the circumferential direction on both sides.

8. Gas turbine plant according to one of claims 1 to 7, characterized in that at the gap (4; 17) a positive step (c) is formed radially on the outside, in that the combustion chamber outer wall (8) in which the gap (4; 17) adjacent end portion (22) in the region of the positive step (c) relative to the circumferentially on both sides of the positive step (c) adjacent areas extends radially outward and / or that the turbine outer wall (12) in the adjacent to the gap (4; 17) end portion (24) in the positive stage (c) relative to the circumferentially on both sides of the positive stage (c) adjacent areas radially offset inwardly.

9. Gas turbine plant according to one of claims 1 to 8, characterized in that at the gap (4; 17) a negative step (d) is formed radially on the outside, in that the combustion chamber outer wall (8) adjoins the gap (4; End portion (22) in the region of the negative stage (d) relative to the in

Circumferentially extending radially inwardly on both sides of the negative step (d) adjacent areas and / or that the turbine outer wall (12) in the gap (4; 17) adjacent end portion (24) in the region of the negative stage (b) relative to in the circumferential direction on both sides of the negative step (d) adjacent areas radially offset to the outside.

10. gas turbine plant according to one of claims 1 to 9, characterized in that in the circumferential direction all transitions between different stages (a, b, c, d) associated areas in the respective end portion (21, 22, 23, 24) of the combustion chamber inner wall (7) and / or the combustion chamber outer wall (8) and / or the turbine inner wall (11) and / or the turbine outer wall (12) are designed to be infinitely variable.