WO2001065073A1

WO2001065073A1 - Turbine installation

Info

Publication number: WO2001065073A1
Application number: PCT/EP2001/002094
Authority: WO
Inventors: Peter Tiemann
Original assignee: Siemens Aktiengesellschaft
Priority date: 2000-03-02
Filing date: 2001-02-23
Publication date: 2001-09-07
Also published as: JP4637435B2; EP1268981B1; DE50106206D1; CN1408048A; EP1268981A1; EP1130219A1; CN1272525C; JP2003525381A

Abstract

The invention relates to a turbine installation (2), especially a gas turbine installation. In particular, the foot plates (32) of the guide blades (18) of adjacent turbine stages (28,30) are interconnected with a clip-type sealing element (42A to 42D) on their rear sides (48) facing away from the gas area (12). This provides a simple seal between adjacent foot plates (32) which is effective regardless of the thermal expansion of the foot plates (32). Said clip-type sealing element (42A to 42D) is also suitable for sealing the tiles (13) of a combustor (4) of the turbine installation (2) together.

Description

description

turbine plant

The invention relates to a turbine system, in particular a gas turbine system.

A gas turbine system is understood in the following to mean a system which comprises a combustion chamber and a turbine which is referred to as the gas turbine and is arranged downstream of the combustion chamber. In the combustion chamber, a fuel gas is burned in a gas space, and the hot gas generated is fed to the turbine and flows through it. The flow path of the hot gas through the turbine is also referred to below as the gas space. The turbine has fixed guide vanes, which extend radially from the outside in the gas space, as well as rotor blades attached to a shaft called a rotor, which extend radially outward from the rotor. When viewed in the longitudinal direction of the turbine, the guide vanes and the rotor blades engage with one another in a tooth-like manner. The turbine generally has several turbine stages, with a guide vane ring being arranged in each stage, i.e. several of the guide blades are arranged next to one another in the circumferential direction of the turbine. The individual guide vane rings are arranged one after the other in the axial direction. Both in the combustion chamber and in the turbine, the gas space is usually clad with plate elements. In the combustion chamber, these are tiles, and in the turbine, the plate elements are formed by so-called base plates of the individual guide vanes.

The gas area of the combustion chamber and the turbine should be as tight as possible. Therefore, low leakage losses between the individual plate elements are aimed for. In particular, leakage losses between two turbine stages are to be prevented. Due to the large temperature ranges in the gas space, there is the problem that a seal expands the must take up and bridge individual plate elements without significantly affecting the seal. This problem is exacerbated by the fact that both the tiles and the base plates of the guide vane are not fastened at their edge regions to adjacent plate elements, so that the plate edges are more or less free and are subject to bending due to thermal expansion. For example, the tiles are usually fastened in the middle and bend approximately spherically when subjected to thermal stress. A seal must therefore - both because of the conical design of the combustion chamber and the turbine in the axial direction - permit both axial and radial mobility.

In the area of the turbine, in the case of a conventional seal, the base plates are provided with a groove on their end face, a sealing plate being inserted into the grooves of two base plates of guide blades from adjacent turbine stages. In the case of the end grooves, the axial-radial mobility of the foot plates is achieved in that the grooves have sloping side walls. Such grooves are, however, very expensive to manufacture. In addition, such a seal is relatively leaky, since a differently rapid thermal expansion behavior of the foot plates and the so-called turbine guide vane carrier to which they are attached must be taken into account. When the turbine starts up, the foot plates expand faster, so that a leakage gap between the foot plates is initially closed. The leakage gap opens again when the turbine guide vane carrier has expanded according to the temperature.

Another problem with the tiles in the combustion chamber is that, due to their spherical bending, such a sealing plate may be subjected to shear until failure.

The invention has for its object to enable a seal that overcomes the disadvantages described. The object is achieved according to the invention by a turbine system, in particular a gas turbine system, with a gas space which is delimited on the outside by adjacent plate elements, a sealing element being assigned to each other adjacent plate elements and connecting them together in a clamp-like manner on their rear sides facing away from the gas space ,

The main advantage is the clamp-like design of the sealing element. The sealing element therefore spans the two plate elements. In the case of thermal expansion, the sealing element follows the plate elements without leaving a gap. The sealing by the sealing element is therefore largely unaffected by thermal expansion.

In order to ensure the best possible seal even with thermal expansions on all sides, the sealing element preferably enables the plate elements to be movable both in the axial and in the radial direction. The sealing element is therefore particularly elastic, both in the axial and in the radial direction. The axial direction here means an extension in the longitudinal direction of the turbine system and the radial direction is an extension perpendicular to the longitudinal axis.

The sealing element preferably has two legs, each of which engages in a groove of adjacent plate elements. This enables the sealing elements to be fastened in a manner that is simple to manufacture.

The groove preferably extends essentially radially from the rear side of the respective plate element. The legs therefore protrude radially outward from the grooves. This configuration of the groove enables simple

Production and in particular high accuracy, for example by grinding or eroding. The advantage of arranging On the back, one can see that the groove does not have to have a special shape with regard to the problem of thermal expansion. The groove and sealing element can therefore be matched to one another very precisely, so that very small leakage gaps are achieved.

In order to enable a simple procedure when assembling the plate elements in the turbine system, the sealing element is preferably constructed in several parts.

The legs of the multi-part sealing element preferably overlap over a common circumferential length. This circumferential length is dimensioned sufficiently large to largely avoid leakages.

In a preferred embodiment, the sealing element is U-shaped, which is easy to implement both in terms of production technology and assembly technology.

In order to achieve a high degree of extensibility, the sealing element has a corrugated structure in the manner of a bellows for absorbing expansions.

The sealing element expediently has this corrugated structure in several directions, so that it can absorb strains in different directions. In particular, the sealing element has a double S-shape.

In a preferred embodiment, the sealing element is arranged between adjacent tiles of a combustion chamber. This ensures a secure seal between the tiles, even if they bend spherically due to the thermal load.

According to a particularly preferred embodiment, the sealing element is arranged between the base plates of adjacent guide blades of a turbine, in particular between the Base plates of guide blades of neighboring turbine stages. The individual base plates are therefore connected to one another in the axial or longitudinal direction of the turbine via clamp-like sealing elements.

In order to achieve simple assembly of the plate elements, in particular the base plates, and at the same time a good sealing of the plate elements both in the circumferential direction and in the axial direction between adjacent turbine stages, the clamp-like sealing element described is preferably for the sealing in the axial direction and another for the sealing in the circumferential direction Sealing element provided. Depending on the direction, differently designed sealing elements are used, in particular for assembly reasons.

The further sealing element preferably has a receiving area into which the plate elements extend. In particular, the sealing element is H-shaped in cross section. The basic idea of this

Design can be seen in the reversal of a conventional sealing principle, in which a sealing plate is introduced into corresponding end grooves of the foot plates. This usually requires reinforcing the edge of the foot plates in the groove area. This is problematic for good cooling of the footplates, since uniform cooling is difficult to achieve due to the different material thicknesses and thermal stresses can occur. In reverse of this sealing principle, the sealing plate is now not inserted into the base plates, but the base plates are inserted into the sealing element. This eliminates the need to reinforce the edge area of the footplate. Coolability is thus simplified and the base plate is cooled homogeneously in all areas, so that no thermal stresses occur. Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. Each shows in a roughly simplified representation:

1 shows a turbine system with a combustion chamber and turbine, FIG. 3 different conventional sealing variants, FIG. 4 the sealing variant according to the invention, FIG. 5-7 different variants of a sealing element, and

8 shows a seal provided in particular for plate elements arranged next to one another in the longitudinal direction.

According to FIG. 1, a turbine system 2, in particular a gas turbine system of a turbine set for a power plant for energy generation, comprises a combustion chamber 4 and a turbine 6, which is arranged in the longitudinal or axial direction 8 of the turbine system 2 after the combustion chamber 4. Both the combustion chamber 4 and the turbine 6 are shown cut open in a partial area. This allows a view into the gas space 10 of the combustion chamber 4 and into the gas space 12 of the turbine 6.

In operation, the combustion chamber 4 is supplied with a fuel gas BG via a gas supply 14, which is burned in the gas space 10 of the combustion chamber 4 and forms a hot gas HG. The gas space 10 is lined with a large number of tiles 13 designed as plate elements. The hot gas HG flows through the turbine 6 and leaves it as a cold gas KG via a gas discharge line 16. The hot gas HG is guided in the turbine 6 via guide vanes 18 and rotor blades 20. A shaft 22 is driven on which the moving blades 20 are arranged. The shaft 22 is connected to a generator 24.

The blades 20 extend radially outward from the shaft 22. The guide vanes 18 have a base plate 32 and an attached blade 21. The guide vanes 18 are each fastened via their base plates 32 on the outside of the turbine 6 to a so-called guide vane carrier 26 and extend radially into the gas space 12. Seen in the longitudinal direction 8, the guide vanes 18 and the rotor blades 20 engage in a tooth-like manner. Several of the moving blades 20 and the guide blades 18 are each combined to form a ring, each guide blade ring representing a turbine stage. In the exemplary embodiment in FIG. 1, the second turbine stage 28 and the third turbine stage 30 are shown as examples.

The base plates 32 of the individual guide blades 18, like the tiles 13, are designed as plate elements which adjoin one another both in the axial direction 8 and in the circumferential direction 33 of the turbine 6 and limit the gas space 12. The location marked with a circle in FIG. 1 is shown enlarged in FIGS. 2 to 4. The seal described for these figures between two foot plates 32, which are arranged next to one another in particular in the longitudinal direction 8, can also be transferred analogously as a seal for the tiles 13 of the combustion chamber 4.

According to FIG. 2, in the conventional variant shown here, the sealing takes place without a special sealing element solely on the basis of an overlap of mutually adjacent foot plates 32. In the overlap area, the two foot plates 32 are designed step-like. With thermal stress and the associated expansion, the two foot plates 32 shift relative to one another in a movement superimposed in the longitudinal direction 8 and in the radial direction 36. As a result, the leakage gap 38 formed between the two foot plates 32 varies. The sealing effect therefore depends crucially on the expansion behavior of the foot plates 32.

The foot plates 32 according to FIGS. 2 to 4 each have a hooking on their rear side 39 facing away from the gas space 12. element 40, via which the foot plates 32 are held on the guide vane support 26 (see FIG. 1). Each footplate 32 typically has two interlocking elements 40, which are designed differently and enable both mobility in the axial direction 8 and in the radial direction 36.

According to FIG. 3, a further conventional sealing arrangement has a sealing plate 41 which is inserted into grooves 44 in the adjacent foot plates 32. The grooves 44 are incorporated in the end faces 46 of the foot plates 32. They have an opening angle α of approximately 15 ° in order to enable the foot plates 32 to move in the radial direction 36. In this embodiment too, a leakage gap 38 is formed between the sealing plate 41 and the foot plates 32, which varies with the expansion due to the thermal load. This variation is due, among other things, to the fact that the base plates 32 expand faster than the guide vane carrier 26 to which they are attached.

In particular, the problems of the temperature dependence of the leakage gap 38 do not occur in the novel embodiment according to FIG. 4. Thereafter, in the area in which the two foot plates 32 adjoin each other, grooves 44 are incorporated in the rear side thereof, which extend essentially radially into the foot plates 32. It should be emphasized that the grooves 44 according to FIG. 4, in contrast to those of FIG. 3, have parallel side walls 50. This enables the grooves 44 to be produced in a particularly simple manner.

A U-shaped sealing element 42A with its two legs 52 is introduced into the grooves 44 and in particular fastened. The attachment takes place, for example, by clamping action or also by welding. The sealing element 42A is designed in particular as a sheet metal element. Its legs 52 essentially extend outward in the radial direction, so that the arch 54 connecting the two legs 52 is spaced apart from the rear side 39. This stretched out guidance enables an elastic behavior of the sealing element 42A, ie it follows the thermal expansions of the foot plates 32. The thermal mobility of the foot plates 32 is thus ensured by the flexible or stretchable sealing element 42A. The mobility is therefore independent of the special design of the grooves 44, so that they can be adapted to the legs 52 in a very precise manner. No or only a very small leakage gap 38 is therefore formed between the legs 52 and the grooves 44, which is independent of the thermal stress on the foot plates 32.

Alternative embodiments of the sealing element 42A are shown by way of example in FIGS. 5 to 7. According to FIG. 5, a sealing element 42B is formed from two separate legs 52, each of which has an arc 54 and overlaps over a circumferential length L. The multi-part design of the sealing element 42B simplifies the assembly, since, for example, the individual legs 52 are simply attached to the corresponding grooves 44 of the respective base plates 32 before the guide vanes 18 are installed, and these are subsequently attached to the guide vane carrier 26. The common circumferential length L is chosen to be as large as possible in order to keep the leakage gap 38 formed between them low for all temperature and operating states.

In an alternative multi-part design of a sealing element 42C according to FIG. 6, only one leg 52A is provided with an arc 54, whereas the second leg 52B is a straight piece of sheet metal. In the case of the multi-part sealing elements 42B, 42C, it is advantageous if the individual legs 52 are pressed against one another in the assembled state and have, for example, a certain spring tension.

According to FIG. 7, a sealing element 42D is provided with a corrugated structure 58, which replaces the simply designed arch 54 according to FIGS. 4 to 6. This corrugated structure 58 preferably extends in several directions, in particular the two parallel to the foot plates 32. In addition, the legs 52 can also be corrugated. The sealing element 42D is thus designed in the manner of a bellows and enables even large thermal expansions to be absorbed in several directions without the leakage gap 38 being enlarged.

For reasons of assembly technology, the sealing elements 42A to 42D preferably connect the base plates 32 of guide vane 18 of adjacent turbine stages 28, 30. In order to achieve a good and easy-to-install seal in the circumferential direction 33, a further sealing element 60 is provided for guide vanes 18 of a guide vane ring which are adjacent to one another in the circumferential direction 33.

According to FIG. 8, the further sealing element 60 is preferably H-shaped in cross section and has two longitudinal legs 62 which are connected to one another via a transverse leg 64. Between the two longitudinal legs 62, two receiving regions 65 are formed, separated from the transverse leg 64, into which the foot plates 32 extend. The side edges 66 of the foot plates 32 are bent outwards approximately vertically from the gas space 12 and nestle directly against the cross leg 64.

This configuration with the receiving areas 65 for the foot plates 32 advantageously enables a material thickness that is homogeneous over the entire foot plate 32, so that uniform cooling of the foot plate 32 is ensured and thermal stresses do not occur in the foot plate 32.

To cool the foot plates 32, a closed cooling system 68 with steam as cooling medium is provided, which is shown in detail in FIG. This closed cooling system 68 has an inflow channel 70 and one

Reverse flow channel 72. The inflow duct 70 is formed between an outer baffle 74 and a baffle 76, which ches between baffle 74 and the base plate 32 is arranged. The baffle plate 76 has flow openings 78 which are designed in the manner of nozzles, so that the cooling medium supplied via the inflow channel 70 passes into the return flow channel 72 along the arrows shown. Due to the nozzle-like mode of operation of the flow openings 78, the coolant is directed against the rear side 80 of the base plate 32 at high speed, so that an effective heat transfer between the coolant and the base plate 21 is realized.

The baffle plate 76 is supported against the base plate 32 and held at a distance via support elements 82, for example in the form of welding spots or welding webs. The baffle plate 70 is attached directly to the side edge 66 of the foot plate 32, in particular welded on, and the baffle plate 68 is attached to the baffle plate 70.

A flow path 84 in the form of a leakage gap is formed between the further sealing element 60 and at least one of the base plates 32, so that, for example, air can flow from the gas space 12 away from the outer space 86 via the flow path 84 into the gas space 12 and thus the sealing area, i.e. the sealing element 60 and the side edges 66 cools.

Claims

claims

1. Turbine system (2), in particular gas turbine system, with a gas space (10, 12) which is delimited on the outside by adjoining plate elements (13, 32), each with a sealing element (42A-D) adjacent plate elements (13, 32 ) is assigned and connects them to one another like brackets on their rear sides (48) facing away from the gas space (10, 12).

2. Turbine system (2) according to claim 1, wherein the sealing element (42A-D) allows mobility of the plate elements (13, 32) both in the axial direction (8) and in the radial direction (36).

3. Turbine system (2) according to claim 1 or 2, wherein the sealing element (42A-D) has two legs (52) which each engage in a groove (44) of the adjacent plate elements (13,32).

4. Turbine system (2) according to claim 3, wherein the groove (44) extends from the rear side (48) of the respective plate element (13, 32) substantially radially into the latter.

5. Turbine system (2) according to one of the preceding claims, in which the sealing element (42B, C) is constructed in several parts.

6. Turbine system (2) according to claim 5 and 3, in which the two legs (52) of the multi-part sealing element (42B, C) overlap over a common circumferential length (L).

7. Turbine system (2) according to one of the preceding claims, in which the sealing element (42A-C) is U-shaped

8. Turbine system (2) according to one of the preceding claims, in which the sealing element (42D) for absorbing expansions has a corrugated structure (58) in the manner of a bellows.

9. Turbine system (2) according to claim 8, wherein the sealing element (42D) has the corrugated structure (58) in several directions.

10. Turbine system (2) according to one of the preceding claims, in which the sealing element (42A-D) between adjacent tiles (13) of a combustion chamber (4) is arranged.

11. Turbine system (2) according to one of the preceding claims, in which the sealing element (42A-D) is arranged between the base plates (32) of adjacent guide vanes (18) of a turbine (6).

12. Turbine system (2) according to one of the preceding claims, which extends in the axial direction (8), and in which the

Sealing element (42A-D) is arranged between axially adjacent plate elements (13, 32), in particular between the base plates (32) of guide blades (18) of mutually adjacent turbine stages (28, 30).

13. Turbine system (2) according to claim 12, in which between the circumferential direction (33) adjacent plate elements (13, 32), in particular between the base plates (32) of guide vanes (18), an additional sealing element (60) with a receiving area (65) is provided, into which the plate elements (13, 32) extend