EP2194239A1 - Nozzle vane carrier - Google Patents

Abstract

The fixed-blade carrier (1) has a number of axial segments (2), where two adjacent axial segments are connected with a number of tie anchors. A support tube is arranged between the adjacent axial segments, where the support tube surrounds the respective tie anchor. The adjacent axial segments are connected with a universal joint (10).

Description

The invention relates to a guide vane carrier, in particular for a gas or steam turbine, which consists of a number of axial segments.

Gas or steam turbines are used in many areas to drive generators or work machines. In this case, the energy content of a fuel or superheated steam is used to generate a rotational movement of a turbine shaft.

In the gas turbine, the fuel is burned in a combustion chamber, wherein compressed air is 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.

To generate the rotational movement of the turbine shaft, a number of rotor blades, which are usually combined into blade groups or rows of blades, are arranged thereon and drive the turbine shaft via a momentum transfer from the working medium. 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 guide vanes are each fixed to a guide vane carrier of the turbine or compressor unit via a blade root, also referred to as a platform. Depending on the design goal of the gas turbine, the guide vanes of the gas turbine can either be mounted on a common guide vane carrier be attached or separate axial segments are provided for each turbine or compressor stage, which are usually rigidly connected together. The use of a plurality of axial segments offers the advantage that on the one hand smaller and therefore less expensive castings are used, on the other hand, the materials of the individual segments can be individually adapted to the physical boundary conditions prevailing in the respective axial region.

In stationary gas turbines, the vane carrier is still usually conical or cylindrical in shape and the vane carrier or its individual axial segments each consist of an upper and a lower segment, the z. B. are interconnected via flanges.

In the design of today's gas turbines usually a particularly high efficiency is a design target in addition to the achievable performance. An increase in the efficiency can be achieved for thermodynamic reasons basically by increasing the outlet temperature with which the working fluid from the combustion chamber of the gas turbine off and flows into the turbine unit. Therefore, temperatures of about 1200 ° C to 1500 ° C are sought for such gas turbines and achieved.

At such high temperatures of the working medium, however, exposed to this components and components are exposed to high thermal loads. In the case of a guide blade carrier composed of a plurality of axial segments, this results in an axial and radial displacement of the axial segments relative to one another on account of the present temperature profile and the different thermal deformation behavior of the individual axial segments. This leads to a high mechanical load on the connection between the axial segments, which can lead to rapid material fatigue with resulting cracks or even breaks in the connection area.

The invention is therefore based on the object to provide a guide vane, which achieves a longer service life with a particularly high operational safety.

This object is achieved by two adjacent axial segments are connected to a number of tie rods.

The invention is based on the consideration that a longer service life of the guide vane carrier would be achievable by avoiding too great a mechanical load due to a different deformation due to temperature differences. In this case, a particularly high mechanical load occurs at Leitschaufelträgern consisting of a plurality of axial segments, in particular in the connection region between the individual axial segments. Since this can lead to damage in a rigid connection of two axial segments, the connection should be flexible. A flexible connection can be achieved, in particular, by the fact that the axial segments are not connected in a materially bonded manner, but are merely braced with one another in a form-fitting manner. For bracing the axial segments a number of tie rods is provided. The tie rods can connect two adjacent axial segments in different ways, for example, by each coaxial openings are introduced into the respective axial segments, through which the tie rod is guided. Then, for example, nuts are set to a thread of the tie rod, which have a larger diameter than the respective opening on the side facing away from the respective adjacent axial segment of the respective opening. As a result, the two axial segments are braced together without entering into a cohesive connection.

The aim of the arrangement of tie rods between the axial segments of the vane support is a connection that can absorb radial or axial displacements by their flexibility, without material damage due to tensile or shear forces. Greater flexibility can be achieved by advantageously bracing a support tube between the adjacent axial segments, which surrounds the respective tie rod. Such a support tube serves as a spacer between the axial segments and the fixing points of the tie rod, which need not necessarily be arranged on the respective axial edge of the axial segment. Due to the greater distance between two axial segments, the flexibility of the connection is increased and damage due to mechanical stress is even better avoided. In this respect, the displacements of the axial segments against each other are made possible by the support tubes and tie rods.

In an advantageous embodiment of the respective tie rods and the respective support tube are designed cylindrical and the inner diameter of the respective support tube is larger than the outer diameter of the respective tie rod. This increases the flexibility of the connection in a torsion or shear of the axial segments against each other, since the support tube rests on the side facing the other axial segment, while the tie rod is fixed by, for example, a nut on the opposite side. This results in different fixed points in a caused by torsion movement of tie rods or support tube from the normal of the radial surface. By a larger inner diameter of the support tube support tube and tie rods are always spaced apart in all radial directions and thus can tilt freely despite different fixed points against the normal of the radial surface.

In order to achieve a good assurance of the respective support tube even with such a tendency, a spherical disk is advantageously arranged at one end of the respective support tube, which is mounted in a cone cone arranged on the respective axial segment. Spherical disc and conical socket then form a ball joint, which, however, has an opening for the continuous tie rod. Through this ball bearing a radial securing of the support tube is ensured even with an inclination against the normal of the radial surface.

In an advantageous embodiment, the number of tie rods is at least six. In particular, in the case of a guide blade carrier, which consists of an upper and lower segment, three tie rods can then be provided for each segment of the respective axial segment, so that a secure three-point connection of the respective segments of the axial segments arises.

In a further advantageous embodiment, the respective adjacent axial segments are connected to a universal joint. By such universal joints an additional gimbal coupling of the respective axial segments is achieved via which a centering and simultaneous transmission of the guiding torque from one to the other carrier is possible, for. B., if only one fixation is provided. This achieves an even safer connection with high flexibility at the same time.

Advantageously, a gas or steam turbine such a vane carrier and a gas and steam turbine plant comprises a gas and / or steam turbine with such a vane carrier.

The advantages achieved by the invention are in particular that a secure and at the same time flexible coupling of the axial segments is achieved by the connection of the axial segments of a guide vane carrier with tie rods. As a result, no damage to the connection can occur when shearing or tensile forces occur due to different thermal expansion behavior of the individual axial segments, and the service life of the guide blade carrier is substantially increased. This makes the use of an axially segmented vane carrier more attractive, which offers further advantages, such as smaller components, easier reparability and the possibility of using different materials for the individual axial segments.

FIG 1

zwei starr verbundene Axialsegmente eines Leitschaufelträgers nach dem Stand der Technik,

FIG 2

zwei über Zuganker verbundene Axialsegmente eines Leitschaufelträgers,

FIG 3

einen Zuganker mit kugelgelagertem Stützrohr,

FIG 4

eine Kugelscheibe und eine Kegelpfanne zur Lagerung des Stützrohre, und

FIG 5

einen Halbschnitt durch eine Gasturbine.

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

FIG. 1

two rigidly connected axial segments of a guide vane carrier according to the prior art,

FIG. 2

two axial segments of a vane carrier connected via tie rods,

FIG. 3

a tie rod with ball-bearing support tube,

FIG. 4

a spherical disc and a cone socket for supporting the support tubes, and

FIG. 5

a half section through a gas turbine.

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

FIG. 1 shows in detail a portion of a vane carrier 1. In stationary gas turbine, the vane support 1 is usually conical or cylindrical shaped and consists of two segments, an upper and a lower segment, the z. B. are interconnected via flanges.

The guide vane carrier 1 shown comprises two axial segments 2. The axial segments 2 are connected to one another via connecting bridges 4. Although this ensures a secure and dimensionally stable connection, however, the previous operating experience shows that due to the different thermal deformation of the axial segments 2, high tensile and shear forces act on the connection bridges 4, which can lead to material failure.

To compensate for these tensile and shear forces are in the guide vane 1 after the FIG. 2 the axial segments 2 over here in total eight elastic connections 6, each with a tie rod 8 (FIG. FIG. 3 ) clamped together. In addition, universal joints 10 are provided, which provide for a centering of the axial segments 2 and the transmission of shear forces, which arise by flow forces, which are transmitted from the guide vanes to the axial segments.

The structure of each elastic connection 6 is detailed in FIG FIG. 3 shown. The central element is the cylindrically massive tie rod 8, which is fastened at its ends 12 to a respective axial segment 2. To the tie rod 8 is a hollow cylindrical support tube 14 is arranged. This acts as a spacer between the axial segments 2. The connection between the axial segments 2 is made via suitable fastening devices on the axial segments 2 having corresponding openings. Between the openings, the support tube 14 is disposed on the side facing the other axial segment 2, then the tie rod 8 is guided through openings and support tube 14, which is then clamped on the opposite side, for example, with nuts. Thus, a solid, but not cohesive connection is reached, which can deform flexibly under tensile and shear forces within certain limits.

In order to achieve an even better flexibility with simultaneous stability of the connection, 14 spherical washers 16 are attached to the respective axial ends of the support tube. These are arranged in corresponding conical cups 18, which are each attached to an associated axial segment 2. The spherical discs 16 and conical cups 18 have an opening for the tie rod 8 and ensure a stable hold while flexible mounting of the support tube 14 to the axial segments. 2

The twist is in FIG. 3 based on the illustrated extensions 20 of the axis of the spherical discs 16 against the axis of the tie rod 8 can be seen. Depending on thermally induced deformation of the axial segments 2, the angle 22 between the variable axes, without causing structural damage to the connection are to be feared. Due to the ball bearing, the elastic connection 6 is therefore particularly easy to deform in the case of radial offset as well as in case of twisting of the respective regions of the axial segments 2, without losing stability.

The spherical discs 16 and conical cups 18 are again in FIG. 4 shown. These may, for example, be designed according to DIN 6319 and be adapted in their geometric dimensions and their material to the respective requirements with respect to stability and flexibility of the elastic connection 6.

An existing of elastically connected axial segments 2 guide vane 1 should be used for example in a gas turbine. The gas turbine 101 according to FIG. 5 includes a compressor 102 for combustion air, a combustion chamber 104 and a turbine unit 106 for driving the compressor 102 and a generator, not shown, or a working machine. For this purpose, the turbine unit 106 and the compressor 102 are arranged on a common turbine shaft 108, also referred to as turbine rotor, to which the generator or the working machine is also connected, and which is rotatably mounted about its central axis 109. 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 has a number of rotatable blades 112 connected to the turbine shaft 108. The blades 112 are annularly disposed on the turbine shaft 108 and thus form a number of blade rows. Furthermore, the turbine unit 106 includes a number of stationary vanes 114, which are also attached in a donut-like manner to a vane support 1 of the turbine unit 106 to form rows of vanes. The blades 112 serve to drive the turbine shaft 108 by pulse transfer from the turbine unit 106 flowing through the working medium M. The vanes 114, however, serve to guide the flow of the working medium M between two seen in the flow direction of the working medium M consecutive blade rows or blade rings. A successive pair of a ring of vanes 114 or a row of vanes and a ring of blades 112 or a blade row is also referred to as a turbine stage.

Each vane 114 has a platform 118 which is arranged to fix the respective vane 114 to a vane support 1 of the turbine unit 106 as a wall element. The platform 118 is a thermally comparatively heavily loaded component, which forms the outer boundary of a hot gas channel for the turbine unit 106 flowing through the working medium M. Each blade 112 is fastened to the turbine shaft 108 in an analogous manner via a platform 119, also referred to as a blade root.

Between the spaced-apart platforms 118 of the guide vanes 114 of two adjacent rows of guide vanes, in each case a guide ring 121 is arranged on a guide vane carrier 1 of the turbine unit 106. The outer surface of each guide ring 121 is also exposed to the hot, the turbine unit 106 flowing through the working medium M and spaced in the radial direction from the outer end of the blades opposite him 112 through a gap. The guide rings 121 arranged between adjacent rows of guide blades serve in particular as cover elements which protect the inner housing in the guide blade carrier 1 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 arranged circumferentially around the turbine shaft 108 around Burners 110 open into a common combustion chamber space. For this purpose, the combustion chamber 104 is configured in its entirety as an annular structure, which is positioned around the turbine shaft 108 around.

By the use of a guide vane carrier 1 of the above-mentioned embodiment, an increased service life and lower repair susceptibility of the gas turbine 1 is achieved. Damage to the vane support 1 due to thermal deformation of the axial segments 2 is avoided by the elastic connections 6. The guide blade carrier 1 can also be used in the compressor 102 or in a steam turbine.

Claims (8)

Guide vane carrier (1),
in particular for a gas or steam turbine (101) consisting of a number of axial segments (2),
wherein two adjacent axial segments (2) are connected to a number of tie rods (8). Guide vane carrier (1) according to claim 1,
in which between the adjacent axial segments (2) a support tube (14) is arranged, which encloses the respective tie rod (8). Guide vane carrier (1) according to claim 2,
in which the respective tie rod (8) and the respective support tube (14) are cylindrical and the inner diameter of the respective support tube (14) is greater than the outer diameter of the respective tie rod (8). Guide vane carrier (1) according to claim 2 or 3,
in which at at least one end of the respective support tube (14) a spherical disc (16) is arranged, which is mounted in a on the respective axial segment (2) arranged conical pan (18). Guide vane carrier (1) according to one of claims 1 to 4, wherein the number of tie rods (8) is at least six. Guide vane carrier (1) according to one of claims 1 to 5, wherein the respective adjacent axial segments (2) are connected to a universal joint (10). Gas or steam turbine (101) with a vane carrier (1) according to one of claims 1 to 6. Gas and steam turbine plant with a gas and / or steam turbine (101) according to claim 7.

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