EP2411631A1

EP2411631A1 - Sealing plate and rotor blade system

Info

Publication number: EP2411631A1
Application number: EP10713877A
Authority: EP
Inventors: Tobias Buchal; Sascha Dungs; Winfried Esser; Birgit Grüger; Oliver Lüsebrink; Mirko Milazar; Nicolas Savilius; Oliver Schneider; Peter Schröder; Waldemar Socha
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2009-03-27
Filing date: 2010-03-25
Publication date: 2012-02-01
Anticipated expiration: 2030-03-25
Also published as: CN102365425A; EP2411631B1; JP2012522161A; WO2010108983A1; ES2517921T3; US20120107136A1; CN102365425B; EP2236759A1; JP5336649B2

Abstract

A rotor blade system (1), in particular for a gas turbine (101), comprising a number of rotor blades (12) arranged annularly on a turbine disk (6), wherein a number of sealing plates (40) is arranged on a side surface (34) of the turbine disk (6), should permit the greatest possible efficiency of a gas turbine together with a simplified design. For this purpose, each sealing plate (40) comprises a number of sheets (50).

Description

description

Sealing plate and blade system

The invention relates to a sealing plate for forming a ring of sealing plates for the rotor of a gas turbine, which sealing plate is formed mainly of a plurality of sheets. Furthermore, the invention relates to a blade system, in particular for a gas turbine, with a number of annularly arranged on a turbine disk rotor, wherein on a side surface of the turbine disk, a number of sealing plates is arranged. It further relates to a gas turbine with such a blade system.

Gas turbines are used in many areas to drive generators or work machines. The energy content of a fuel is used to generate a rotational movement of a turbine shaft. For this purpose, the fuel is burned in a combustion chamber, compressed air being supplied by an air compressor. The working medium produced in the combustion chamber by the combustion of the fuel, under high pressure and at high temperature, is guided via a turbine unit arranged downstream of the combustion chamber, where it relaxes to perform work.

In order to generate the rotational movement of the turbine shaft, a number of rotor blades, which are usually combined into blade groups or blade rows, are arranged thereon. In this case, a turbine disk is usually provided for each turbine stage, to which the rotor blades are fastened by means of their blade root. For guiding the flow of the working medium in the turbine unit also commonly associated between adjacent blade rows with the turbine housing and combined into rows of guide vanes are arranged. The combustion chamber of the gas turbine can be designed as a so-called annular combustion chamber, in which a plurality of burners arranged in the circumferential direction around the turbine shaft discharge into a common combustion chamber space surrounded by a high-temperature resistant surrounding wall. For this purpose, the combustion chamber is designed in its entirety as an annular structure. In addition to a single combustion chamber can also be provided a plurality of combustion chambers.

Directly adjacent to the combustion chamber is usually followed by a first row of guide vanes of a turbine unit, which forms a first turbine stage of the turbine unit together with the immediately following blade row seen in the flow direction of the working medium, which are usually followed by further turbine stages.

In the design of such gas turbines in addition to the achievable power usually a particularly high efficiency is a design target. For thermodynamic reasons, an increase in the degree of efficiency can basically be achieved by increasing the outlet temperature at which the working medium leaves the combustion chamber and flows into the turbine unit. Temperatures of about 1200 ⁰ C to 1500 ⁰ C are sought for such gas turbines and also achieved.

At such high temperatures of the working medium, however, exposed to this components and components are exposed to high thermal loads. In order to protect the turbine disk and the turbine shaft from the penetration of hot working medium, sealing plates are provided on the turbine disks, as is known from EP 1 944 472 A1, for example, which are mounted on the turbine disk in a circle around the turbine surfaces on the surfaces normal to the turbine axis. In this case, a sealing plate is usually provided per turbine blade on each side of the turbine disk. These overlap like scales and usually have a sealing wing, which is up to such extends to the adjacent vane that a penetration of hot working medium is avoided in the direction of the turbine shaft.

However, the sealing plates fulfill even more functions. On the one hand they form the axial fixation of the turbine blades by appropriate fasteners, on the other hand, they not only seal the turbine disk against penetration of hot gas from the outside, but also avoid leakage of guided inside the turbine disk cooling air, which usually forwarded to the cooling of the turbine blades in selbige becomes.

Such sealing plates with integrated sealing wings are usually produced by vacuum investment casting (eg by lost-wax casting). In this case, a certain allowance must be provided in order to be able to compensate for process-related dimensional inaccuracies. Due to geometry - the sealing plates have wide, very thin areas and mass accumulations at other places - a delay and a certain porosity can not be avoided, especially in the thin areas under vacuum investment casting. Due to the requirement profile of the sealing plates, however, these are often made of alloys which can not be produced close to the final contour in a process other than the vacuum investment casting described.

For this reason, after casting to remove porosity, such sealing plates often have to be compacted by means of hot isostatic pressing at high temperatures and high pressure, and finally brought to a finished contour by complex mechanical machining methods. On the one hand, the described process with hot isostatic pressing, mechanical reworking and the associated loss of material is very complicated and costly; on the other hand, inhomogeneous mass distribution can continue to exist even after the post-processing, which later severely restrict the function of the sealing plate during operation and cause losses may mean in terms of the efficiency of the gas turbine. It is also known from GB 947,553 to secure the blades of a gas turbine by massive cover rings against axial displacement. In this case, obliquely set baffles are attached to the cover rings with openings which capture the provided in the disc cavity cooling air and should lead through arranged in the cover openings openings to the blades. In this embodiment, however, cast cover rings are again required.

The invention is therefore based on the object, a

Specify sealing plate and a blade system, which allows for a maximum efficiency of a gas turbine simultaneously simplified construction.

This object is achieved with a sealing plate according to the features of claim 1.

The invention is based on the consideration that a particularly simple manufacturability of the sealing plate would be achieved if the hitherto customary investment casting method with subsequent mechanical finishing could either be simplified or completely replaced by another production method. In this case, other casting methods than the described vacuum investment casting due to the materials chosen for the sealing plates are out of the question. Therefore, the sealing plate should not be made in a primary molding process such as casting, but in a forming process. In order to be able to realize the complex shape of the sealing plates, the sealing plates should be made of a plurality of base parts by forming. This can be achieved particularly easily by forming prefabricated metal sheets; the sealing plate should therefore be made of a plurality of sheets.

The sealing plate comprises two parallel to the sealing plate plane arranged, spaced apart sheets. These form the respective faces of the Sealing plate and the distance between the two sheets, the thickness of the sealing plate can be selected exactly. It remains between the sheets a gap that can be used to carry out cooling air and so for internal cooling of the sealing plate. On the one hand, therefore, a particularly simple construction of the sealing plate is possible, on the other hand can withstand the most adverse circumstances during operation by an active component cooling the sealing plate, so that particularly high temperatures during operation of the gas turbine are possible and thus a particularly high efficiency is achieved.

In an advantageous embodiment, an intermediate plate with a number of recesses is arranged between the sheets. Such an intermediate plate stabilizes the connection between the sheets acting as end faces of the sealing plate and allows a precise, targeted choice of the distance. Through the recesses in the intermediate plate while still a passage of cooling air through the interior of the sealing plate with the advantages described possible.

Advantageously, the respective sheet has a fold on the side facing the center of the turbine disk. Such a fold, which can be easily manufactured by forming, makes it possible to fix the sealing plate on the side facing the center of the turbine disk in a groove provided for this purpose, thus ensuring a secure hold of the sealing plate and of the rotor blades on the turbine disk. This offers the advantage that despite the modified construction of the sealing plate, the fastening devices previously used on the turbine disk need not be modified and thus a particularly simple construction of the LaufSchaufelsystems with sealing plate and turbine disk is possible.

In order to ensure a particularly simple supply and supply of the sealing plate with cooling air, the respective sheet advantageously has a number of cooling air holes on. On the inlet side, the cooling air holes should be facing the turbine disk so that a cooling air supply through the turbine disk into the sealing plate is possible, cooling air holes should be provided on the outlet side, which have, for example, adjacent components or mounting plates of the sealing plate, so that an active cooling of these components is possible ,

In order to ensure the function of sealing vanes for sealing the areas lying between two turbine disks against penetration of hot gas from the hot gas duct of the gas turbine, the sealing plate advantageously comprises a plate pointing out of the sealing plate plane. This should extend to the adjacent blade row and thus prevent the penetration of hot gas in the direction of the turbine shaft in order to protect the components provided there.

In an advantageous embodiment, the various sheets are welded and / or soldered together. As a result, a particularly simple construction of the sealing plate made of a plurality of sheets is possible.

The thus achieved construction of the sealing plate, in particular in a three-layer design with two end faces forming sheets and an intermediate plate with recesses for cooling air, offers itself to provide a tongue and groove connection for sealing a plurality of juxtaposed sealing plates in the circumferential direction. For this purpose, a groove and / or a spring is advantageously arranged in the region of an edge of the respective sealing plate. Such a groove is possible in a three-layer design of the sealing plate in the manner described above simply by shortening the intermediate plate on the edge or a spring by extending the intermediate plate at the edge. As a result, a particularly good and easy-to-implement seal in the circumferential direction between a plurality of sealing plates is possible. Advantageously, a gas turbine such a blade system and a gas and steam turbine plant comprises a gas turbine with such a blade system.

The advantages achieved by the invention are in particular that a particularly simple design and construction of the sealing plate is possible by the construction of the sealing plate by means of a plurality of sheets. The production and material costs are low compared to other methods. Due to the flexible combination of materials, the use of materials and the resulting costs can be reduced. Post-processing of the large plane surfaces - as required in the casting process - is not required when preformed metal sheets are used, although a particularly good sealing effect of the sealing plate during operation is nevertheless achieved. As a result of this and due to the active cooling of the components by cooling air passage in the sealing plate, there are fewer restrictions for the hot gas temperature in a gas turbine and, overall, a higher degree of efficiency can be achieved.

An embodiment of the invention will be explained in more detail with reference to a drawing. Show:

1 shows a half section through a blade system,

2 shows a section through a sealing plate after the casting process,

3 shows a cross section through a sealing plate after mechanical reworking,

4 shows a cross section through a sealing plate made of several sheets,

5 shows a plan view of an intermediate plate for a sealing plate, 6 is a plan view of a sealing plate made of a plurality of sheets, and

7 shows a half section through a gas turbine.

Identical parts are provided with the same reference numerals in all figures.

1 shows a rotor blade system 1 as a section through the outer periphery of a mounted on a turbine shaft turbine disk 6 a blade stage of a gas turbine according to the prior art.

A blade 12 is arranged in a blade holding groove 30 with its blade root 32. The blade root 32 of the blade 12 is fir-tree-shaped in cross-section and corresponds to the Christmas tree shape of the blade holding groove 30. The schematic representation of the contour of the blade root 32 and the blade holding groove 30 is shown rotated by 90 ° with respect to the rest of FIG. Thus, the illustrated blade retaining groove 30 extends between the side surfaces 34 of the turbine disk 6.

Respectively adjacent guide vanes 36 are not shown in detail, which - viewed in the flow direction of the working medium of the gas turbine - upstream and downstream of the blade 12 are arranged. The vanes 36 are arranged radially in wreaths.

On both sides of the turbine disk 6, sealing disks 40 are used circumferentially on each of the side walls 34 in a scale-like manner. These are held on their upper side in an inserted into the blade 12 groove 42 and fixed on its underside by a locking pin not shown.

The sealing plates 40 fulfill several tasks: On the one hand, they seal by attached, essentially in Axial and azimuthal direction extending sealing vanes 46, the space between the turbine disk 36 and adjacent vanes 36 against ingress of hot working fluid M from the turbine. On the other hand, the sealing plates 40 also provide for an axial fixation of the blade root 32 in the blade retaining groove 30 and thus secure it against axial displacement. The radial and azimuthal securing has already been achieved by the Christmas tree shape of the blade retaining groove 30. Furthermore, the sealing plates 40 prevent leakage of cooling air introduced through cooling air channels 48 through the turbine disk 36 into the blade root 32 and the rotor blade 12.

2 and 3 schematically show a cross section perpendicular to the sealing plate plane 49 of a sealing plate 40 according to the prior art in two different stages of the manufacturing process.

The sealing plate 40 is first cast, as shown in FIG 2, with a certain allowance. In this case, usually a vacuum investment casting method is used and then the sealing plates 40 are compacted after casting to eliminate porosity by means of hot isostatic pressing. Subsequently, a mechanical post-processing is carried out in order to bring the sealing plate 40 into the finished contour shown in FIG.

Such a manufacturing process is relatively complicated and expensive. In order to simplify the manufacturing process for the sealing plate 40, the sealing plate 40 should therefore be made of a plurality of sheets 50, as shown in FIG 4.

The sealing plate 40 according to FIG 4 initially comprises two parallel to the sealing plate plane 49 spaced from each other arranged plates 50, between which an intermediate plate 52 is introduced. This results in a total of a three-layer design of the sealing plate 40. At the middle of the rotor disc-facing side, the plates 50 thereby include bends 54, which emulate the previously cast form of the sealing plate 40. The intermediate plate 52 is not solid, but includes a number of recesses 56, which are also shown in the plan view in FIG 5. As a result, a supply of cooling air K through cooling air holes 58 is possible, which allow active cooling of the sealing plate 40.

Furthermore, the sealing plate 40 comprises a plane 50 which points out of the sealing plate plane 49 and forms the sealing wing 46. To stabilize the sealing wing while another support plate 60 is provided. The cooling air bores 58 are aligned on the outlet side so that cooling air K exiting from the sealing plate 40 flows against the sealing vanes 46 and further adjacent components and thus also cools.

The individual sheets 50 are welded together, which allows a particularly simple construction of the sealing plate 40. Alternatively, the sheets 50 can also be soldered at high temperatures.

The sealing plate 40 is again shown in FIG 6 in the plan. In this case, the intermediate plate 52 is displaced in the circumferential direction in relation to the two parallel aligned metal sheets 50, so that a groove 64 forms on one edge 62 of the sealing plate 40 and a spring 68 on the opposite edge 66. In this way, adjacent sealing plates 40 can be sealed in the circumferential direction by means of a tongue and groove connection.

A gas turbine 101, as shown in FIG. 7, has a compressor 102 for combustion air, a combustion chamber 104 and a turbine unit 106 for driving the compressor 102 and a generator or a working machine (not shown). For this purpose, the turbine unit 106 and the compressor 102 are arranged on a common, also referred to as a turbine rotor turbine shaft 108, with which the generator or the working machine is connected, and to its central axis 109 is rotatably mounted. The combustor 104, which is in the form of an annular combustor, is equipped with a number of burners 110 for combustion of a liquid or gaseous fuel.

The turbine unit 106 includes a blade system 1 having a number of rotatable blades 12 connected to the turbine shaft 108. The rotor blades 12 are arranged in a ring shape on the turbine shaft 108 and thus form a number of blade rows. Furthermore, the turbine unit 106 includes a number of stationary vanes 36 which are also annularly attached to a vane support 110 of the turbine unit 106 to form rows of vanes. The rotor blades 12 serve for driving the turbine shaft 108 by momentum transfer from the working medium M flowing through the turbine unit 106. The guide blades 36, on the other hand, serve to guide the flow of the working medium M between two respective rows of rotor blades or rotor blade rings viewed in the flow direction of the working medium M. A sequential pair of a ring of vanes 36 or a row of vanes and a ring of rotor 12 or a row of blades is also referred to as a turbine stage.

Like the rotor 12, each vane 36 has blade root 118 which is arranged to fix the respective vane 36 to the vane support 110 of the turbine unit 106 as a wall member. The blade root 118 is a thermally comparatively heavily loaded component that forms the outer boundary of a hot gas channel for the turbine unit 106 flowing through the working medium M.

Between the spaced platforms 118 of the vanes 36 of two adjacent rows of vanes, a ring segment 121 is disposed on a vane support 110 of the turbine unit 106. The outer surface of each ring segment 121 is also the hot, exposed to the turbine unit 106 flowing through the working medium M and spaced in the radial direction from the outer end of the opposed blades 12 by a gap. In this case, the ring segments 121 arranged between adjacent guide blade rows serve in particular as cover elements which protect the inner housing in the guide blade carrier 110 or other housing built-in components against thermal overstress by the hot working medium M flowing through the turbine 106.

The combustion chamber 104 is configured in the exemplary embodiment as a so-called annular combustion chamber, in which a plurality of burners 110 arranged around the turbine shaft 108 in the circumferential direction open into a common combustion chamber space. To this end, the combustion chamber 104 is configured in its entirety as an annular structure positioned around the turbine shaft 108.

A sealing plate 40 for a blade system 1, which is made of different sheets 50, on the one hand offers a particularly simple and cost-effective production, on the other hand can be achieved by the active component cooling a particularly high efficiency of a gas turbine 101.

Claims

claims

1. sealing plate (40) for forming a ring of sealing plates (40) for the rotor of a gas turbine, characterized in that the sealing plate of a plurality of sheets (50) is formed and two spaced apart, opposite to the sealing plate plane (49) comprises parallel plates (50).

Second sealing plate (40) according to claim 1, wherein between the sheets (50) an intermediate plate (52) is arranged with a number of recesses (56).

3. Sealing plate (40) according to any one of claims 1 or 2, wherein - viewed in the operating position - the respective plate (50) at the center of the turbine disc (6) facing side has a fold (54).

4. sealing plate (40) according to any one of claims 1 to 3, wherein the respective plate (50) has a number of cooling air holes (58).

5. sealing plate (40) according to one of claims 1 to 4, which comprises a from the sealing plate plane (49) facing sheet (50).

6. sealing plate (40) according to any one of claims 1 to 5, wherein a number of sheets (50) is welded and / or soldered.

7. sealing plate (40) according to one of claims 1 to 6, wherein in the region of an edge (62, 66) of the respective sealing plate (40) has a groove (64) and / or a spring (68) is arranged.

8. Blade system (1), in particular for a gas turbine (101), with a number of annularly on a turbine disk (6) arranged blades (12), wherein on a side surface (34) of the turbine disk (6) a number of sealing plates (40 ), characterized in that the respective sealing plate (40) is designed according to one of the preceding claims.

9. gas turbine with a rotor blade system (1) according to claim 8.

10. Gas and steam turbine plant with a gas turbine (101) according to claim 9.