EP2211023A1 - Guide vane system for a turbomachine with segmented guide vane carrier - Google Patents

Abstract

The guide vane system (1) has multiple guide vane rows and a vane support (4), where the vane support is segmented within the range of a guide vane row. A segment (24) is extended over the entire radial expansion of the vane support, and the connection of the respective segment is detachable with another vane support.

Description

guide vane

The invention relates to a guide vane system, in particular for a gas turbine, with a number of vane rows and a vane carrier. It further relates to a gas turbine with such a guide vane system.

Gas turbines are used in many areas to drive generators or work machines. In this case, 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.

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, guide vanes are also usually arranged between adjacent rotor blade rows and connected to the turbine housing, which are combined into rows of guide blades. These are attached via a blade root to a usually hollow cylindrical or hollow cone-shaped guide blade carrier and fastened on its side facing the turbine axis via a blade head on a common inner ring of the respective guide blade row. In stationary gas turbines, this often consists of an upper and a lower half, which are connected to each other via flanges.

In the design of such gas turbines in addition to the achievable power usually a particularly high efficiency a design goal. An increase in the efficiency can be achieved for thermodynamic reasons basically by increasing the exit temperature, with which the working fluid flows from the combustion chamber and into the turbine unit. Temperatures of about 1200 ° C to 1500 ° C for such gas turbines are sought and achieved.

However, such high temperatures of the working medium are well above the melting temperature of the component materials used for example in the outflow of the combustion chamber, so that the critical components to ensure the required function of the gas turbine must be strongly cooled and protected with complex coating systems. In some cases, it can not be ruled out that, despite the use of these highly developed and proven technologies for the cooling and coating of the blades, premature replacement of guide vanes is necessary since the vane function is unduly impaired, for example, by partial loss of the coating or closure of cooling air bores. For large stationary gas turbines, such an exchange measure can last at best several days, but on average about two weeks, thereby causing an unwanted and expensive interruption of the operation of the gas turbine or a combined cycle power plant in which the gas turbine is used.

The invention is therefore based on the object, a guide vane system, in particular for a gas turbine to specify, which allows a particularly simple exchange of vanes while maintaining a particularly high efficiency and thus designed for a particularly short repair time.

This object is achieved according to the invention in that the guide vane carrier is segmented in the region of a guide vane row, wherein a segment extends over the entire radial extent extends the guide vane and the connection of the respective segment with the rest of the vane carrier is releasable.

The invention is based on the consideration that a shortened repair time would be possible by a particularly simple interchangeability of the vanes, if their assembly and disassembly could be simplified. Currently, because of the structural conditions in modern annular combustor machines, the entire turbine must be uncovered to allow access to the vanes. In this case, the guide vanes are within the guide vane carrier, which consists of an upper and a lower solid casting in stationary gas turbines, and thus also has to be disassembled to replace the vanes. In order to avoid this uncovering and lifting of the guide vane carrier, the guide vane carrier should therefore be segmented in the region of a guide vane row. This makes it possible to reach the area under the segments of the vane carrier only by uncovering individual segments. In order to ensure accessibility of the guide vanes, a segment should extend over the entire radial extent of the guide vane carrier and the connection of the respective segment to the rest of the vane carrier be solvable. Thus, for a repair or replacement of a vane no longer the entire vane carrier must be revealed, but it is only the connection of the respective segment with the rest of the vane support dissolved and - as the segment extends over the entire radial extent of the vane support - allows removal of the each segment directly reaching the vanes and replacing them.

The highest temperatures in the gas turbine are at the outlet of the combustion chamber. Thus, the first turbine stage vane, ie the vane closest to the combustor, is exposed to these highest temperatures and is subject to the greatest wear. Accordingly In particular, in the case of this turbine guide vane premature replacement is to be expected as a result of damage caused by clogging of the cooling air bores (eg by inwardly oxidizing cooling air bores). In order to simplify the replacement of these guide vanes, the guide vane carrier should therefore advantageously be segmented in the region of the guide vane row closest to a combustion chamber of the gas turbine.

In order to achieve accessibility of all the vanes of a row of vanes, advantageously a plurality of segments should be provided, which extend in their entirety over the entire circumferential direction of the vane support. Thus, in each peripheral section, an exchange of vanes by the respective segment is taken over the relevant vane. The exact geometric design of the segmentation should be adapted in a meaningful way to the handling of the machine.

In a further advantageous embodiment, the respective connection is a screw connection and / or a tongue and groove connection. By screwing a particularly simple releasable connection of segments with each other and / or with the rest of the vane carrier is possible. Due to the circular arrangement of the segments around the entire circumference of the gas turbine, however, a hooking in the manner of a tongue and groove joint is possible in which the individual segments are bolted only to each other and are merely hooked to the rest of the guide blade carrier. In this way, a particularly simple disassembly and assembly of the individual segments is possible.

In order to further simplify the dismantling of the guide vanes now achievable by the segmentation of the guide blade carrier, the guide blade fixation should be provided in a meaningful way such that an undisturbed disassembly of an arbitrarily circumferentially located segment is ensured is, so that depending on the position of the blade to be replaced only the affected segment must be dismantled. For this purpose, in an advantageous embodiment, a guide vane of the respective vane row is releasably connected to the rest of the vane carrier. As a result, after the removal of the segment, the guide vane can be dismantled by releasing the connection with the rest of the vane carrier.

In order to enable not only on the blade root side, but also on the blade head side of the respective vane easy disassembly of the vane, the vane of the respective vane row is advantageously releasably connected on its side facing the turbine axis with an inner ring in the radial direction. Thus, a radial distance of the vane is possible. This allows a particularly simple exchange.

A particularly simple replacement of the guide vane is possible by the fixation of the guide vane on the inner ring is designed as a simple connector. For this purpose, the respective vane advantageously comprises a spring which can be inserted in the radial direction into a groove of the inner ring. As a result, the shovel-side connection of the vane to the rest of the vane carrier can be easily solved to replace the respective vane and the respective vane are pulled out of the turbine in the radial direction simply by loosening the connector. It is ensured by the blade-side fixation of the vane on the vane support during operation, a sufficient assurance.

In the previous design, the guide vanes of a row of guide vanes were fixed to the inner ring via a connection secured with pins, so that the entire inner ring had to be removed for removal and subsequently the guide vanes could be removed. In a releasable connection, for example in the manner of a simple plug connection of the guide vanes with the inner ring should therefore the inner ring with the Brennkammernabe, ie a fixed to the combustion chamber and thus the static part of the gas turbine component are fixed. For this purpose, the inner ring is advantageously connected to a combustion chamber hub. This can be done for example by a fixation by welding, clamping o. Ä. When redesigning a gas turbine, the inner ring can also be manufactured directly as part of the fuel chamber hub.

Between the individual guide vanes, grooves are provided both on the blade root and on the blade head in the previous design, in which sealing plates are arranged in the circumferential direction between the guide vanes. However, if the vanes are to be removed individually, however, the sealing plates located in the grooves of the vane foot and the vane head block the vanes and may thus possibly prevent disassembly. Therefore, the fixation of the sealing sheets should be changed so that their removal is possible and thus removal of individual vanes is simplified. For this purpose, at the adjacent side of the guide vane facing sides of the blade root and / or blade head advantageously introduced bends, in which the sealing plate is fixed by means of a clamping element. Before the removal of the guide vanes thus the clamping element can be solved and the sealing plate can be removed, so that a particularly simple disassembly of the vane is possible.

In an advantageous embodiment, such a guide vane system is used in a gas turbine. In order to allow a particularly easy accessibility of the guide blade system for the exchange of individual guide vanes, an outer housing of the gas turbine thereby advantageously comprises a manhole, through which easy access to the segments of the guide vane support for the assembly personnel is possible.

Advantageously, a gas and steam turbine power plant comprises such a gas turbine.

The advantages achieved by the invention are in particular that the segmentation of the guide vane carrier in the region of a guide vane row into segments which extend over the entire radial extent of the vane carrier and their connection with the rest of the vane carrier is solvable, a particularly simple exchange of vanes of a row of vanes is possible because not the entire turbine has to be revealed in such an exchange. The cost of replacing the blades is significantly reduced and the required period of silence of the gas turbine can be significantly reduced. Such a simplified replacement, in particular the first vane stage directly after the combustion chamber also allows an increase in the outlet temperature in conjunction with an increase in the efficiency of the gas turbine, since the simplified exchange option of the vanes on their durability less consideration must be taken. In this case, variable exchange concepts are conceivable during operation. Furthermore, such a design enables a comparatively faster test of new prototypes of guide vanes, for example with novel coatings or new cooling concepts, through the simplified exchange in research and development.

FIG 1

ein Leitschaufelsystem mit verhakten Segmenten im Längsschnitt,

FIG 2

ein Leitschaufelsystem mit verschraubten Segmenten im Längsschnitt,

FIG 3

einen Querschnitt durch die Segmente senkrecht zur Turbinenachse,

FIG 4

eine Brennkammernabe einer Ringbrennkammer,

FIG 5

die schaufelkopfseitige Fixierung der Leitschaufel nach dem Stand der Technik

FIG 6

die schaufelkopfseitige Fixierung der Leitschaufel mit einer Steckverbindung,

FIG 7

eine Brennkammernabe mit dem Innenring als Bestand- teil,

FIG 8

einen Querschnitt durch zwei benachbarte Leitschaufeln senkrecht zur Turbinenachse mit in Nuten fixierten Dichtelementen nach dem Stand der Technik,

FIG 9

einen Schnitt durch zwei benachbarte Leitschaufeln senkrecht zur Turbinenachse mit Spannelementen fixierten Dichtelementen, und

FIG 10

einen Halbschnitt durch eine Gasturbine.

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

FIG. 1

a guide blade system with hooked segments in longitudinal section,

FIG. 2

a guide blade system with bolted segments in longitudinal section,

FIG. 3

a cross section through the segments perpendicular to the turbine axis,

FIG. 4

a combustion chamber hub of an annular combustion chamber,

FIG. 5

the blade-head-side fixing of the guide vane according to the prior art

FIG. 6

the blade-head-side fixation of the vane with a plug connection,

FIG. 7

a combustion chamber hub with the inner ring as a component,

FIG. 8

a cross section through two adjacent vanes perpendicular to the turbine axis with grooved in sealing elements according to the prior art,

FIG. 9

a section through two adjacent vanes perpendicular to the turbine axis with clamping elements fixed sealing elements, and

FIG. 10

a half section through a gas turbine.

The same components are provided in all figures with the same reference numerals.

FIG. 1 shows a guide blade system 1 in sections in the region of the first two in hot gas direction to a combustion chamber 2 following vanes. In this case, the illustration shows a half section through the upper half of a conically shaped guide blade carrier 4 and the respective vanes 6 of the first turbine stage and guide vanes 8 of the second turbine stage arranged in the vertex of the guide vane ring.

The vanes 6, 8 each comprise a blade root 10, 12 and a blade head 14, 16, via which their attachment to the other components takes place. The guide vanes 6, 8 of the first and second turbine stage are fastened with their blade roots 10, 12 on the guide blade carrier 4 and at their respective blade heads 14, 16 fixed to inner rings 18, 20. Here, both the inner ring 20 and the vane support 4 include a plurality of cooling channels, not shown, which provide a cooling air supply to the guide vane 4, the vanes 6, 8 and the inner ring 20 to sufficiently cool these components due to the high hot gas temperatures.

The highest temperatures occur at the outlet of the combustion chamber 2, which is why the vanes 6 of the first row of vanes are exposed to the highest temperatures. As a result, despite all cooling measures, damage to the guide vanes 6 and thus an early replacement of these guide vanes 6 that is required can not be ruled out. In order to enable a particularly simple exchange of the guide vanes 6, the guide vane carrier 4 is segmented in the region of the first vane row.

The vane support 4 thus comprises a number of segments 24 and a remaining vane support 26 which is not segmented. The segments 24 and the remaining vane support 25 are detachably connected. In the FIG. 1 the connection is effected via a hooking by means of grooves 28 and springs 30 introduced into the segments 24 and the remaining guide blade carrier 26. Such a connection of the segments 24 is also provided with the combustion chamber wall 32.

The rest of the vane carrier 26 can also be understood as meaning an upper and / or a lower half of a ring-shaped vane carrier which is annular in cross-section, as is already known in stationary gas turbines. In this case, at least two segments 24 are provided on each half of the remainder of the vane carrier. In this respect, more segments 24 are always provided in the axial section of the first row of guide vanes for the circumference than remaining guide blade carriers 26 in the adjoining axial section.

By hooking the connection of the respective segments 24 can be solved with the rest of the guide blade carrier 26 and the segment 24 can be removed radially. Thus, the vanes 6 of the first turbine stage can be reached without completely revealing the entire turbine from the outside. The vane 6 of the first turbine stage is releasably secured via the blade root 10 by means of a fastening device 34 on the rest of the vane carrier 26. After removal of the segment 24, this connection can be solved and the vane 6 is radially accessible from the outside. The blade head 14 of the guide vane 6 of the first turbine stage in this case comprises a spring 36 which is inserted in a groove 38 of the inner ring 18. The attachment to the inner ring 18 is thus designed only as a plug-in connection, so that the guide blade 6 can be easily removed to the outside after loosening the fastening device 34.

FIG. 2 also shows the vane system 1 as in FIG. 1 However, here the detachable connection of the segment 24 with the rest of the guide blade carrier 26 is realized via a screw 40. The entanglement of the segment 24 with the combustion chamber wall 32 via grooves 28 and springs 30 is unchanged. Such a connection with a screw 40 may be desirable depending on strength or geometric requirements in the guide vane system 1.

FIG. 3 now shows a perpendicular to the turbine axis section through the vane system 1 at the height of the segments 24. In the example shown a total of twelve segments 24 are provided, which are connected via flanges 52, for example with a screw connection. As a result, a secure hold of the multi-segmented portion of the vane support 4 is ensured, even if the individual segments 24 only via an entanglement with the rest of the vane support 26 as in FIG. 1 are shown connected. The segmentation can also be done in other ways and adapted to the handling of the machine.

FIG. 4 shows the combustion chamber hub 54 of a gas turbine. This includes a groove 56 into which the in FIG. 1 and 2 shown inner ring 18 is used. Furthermore, a groove 58 is provided, in which a sealing plate for sealing the gap between the blade root 14 of the guide vane 6 of the first turbine stage and the combustion chamber hub 54 is provided.

FIG. 5 shows a known attachment of the Leitschaufelfußes 14 to the combustion chamber hub 54 of the gas turbine in detail. In this case, the blade root 14 comprises a spring 36 which is inserted into a groove 38 of the inner ring 18. There, the guide vane of the first turbine stage 6 is fixed by means of a pin 60. The inner ring 18 is then inserted into the groove 56 of the combustion chamber hub 54. At the same time, the blade root 14 includes a groove 62 for receiving a sealing plate 64, which also lies in the groove 58 of the combustion chamber hub 54.

Since the pin 60 is parallel to the turbine axis, a complete removal of the inner ring 18 is required for disassembly of the guide vane 6 of the first turbine stage so far. Only after the removal of the pin 60 can be removed and the vane 6 removed. Therefore, the connection of the vane 6 with the combustion chamber hub 54 is now more as in FIG. 6 shown:

The spring 36 of the blade root 14 is no longer connected via a pin to the inner ring 18 in the groove 38, but is merely stuck to the inner ring 18. Instead, the inner ring 18 is secured to the combustion chamber 54 by a pin 66 or screw. As a result, the guide vanes 6 can also be removed individually, without disassembling the inner ring 18. A secure hold of the guide vanes 6 is still on the fastening device 34, as in FIG. 1 and 2 shown, ensured.

In such an embodiment, it is also possible to use the inner ring 18 directly as part of the combustion chamber hub 54 finished. As a result, no separate parts are required. Such a configuration is in FIG. 7 shown.

FIG. 8 shows a section perpendicular to the turbine axis through two adjacent vanes 6 of the first turbine stage, as is common in the prior art. In this case, grooves 68 are introduced into the blade feet 10 and blade heads 14 on the surface facing the adjacent guide blade 6, into which sealing plates 70 are inserted which close the gaps between the blade roots 10 and blade heads 14. However, these sealing plates 70 may be a hindrance in a radial removal of individual vanes 6.

Accordingly, a plurality of guide vanes 6 are first to be unlocked and displaced in the circumferential direction, so that a guide blade 6 comes out of engagement of the sealing plates 70 and can be radially expanded.

To get around this, as in FIG. 9 shown, the grooves 68 replaced by folds 72. The sealing plates 70 are now inserted into the folds 72 and secured by clamping elements 74 there. To remove a single guide vane 6, the clamping element 74 can now be released and the sealing element 70 removed. Then, the guide vane 6 can be removed radially. Thus, an exchange of individual vanes is greatly facilitated.

Such a guide blade system 1 described here is advantageously used in a gas turbine 101.

A gas turbine 101, as in FIG. 10 has a compressor 102 for combustion air, a combustion chamber 2 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, also referred to as a turbine rotor turbine shaft 108, with which the generator or the working machine is connected, and to its turbine axis 109 is rotatably mounted. The running in the manner of an annular combustion chamber 2 is equipped with a number of burners 110 for the 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 6, 8, 114 which are also annularly attached to a vane support 4 of the turbine unit 106 to form rows of vanes.

The blades 112 serve to drive the turbine shaft 108 by momentum transfer from the turbine unit 106 flowing through the working medium M. The vanes 6, 8, 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 blade root 118, which is arranged to fix the respective vane 114 on a vane support 4 of the turbine unit 106 as a wall element. Each blade 112 is fixed to the turbine shaft 108 in a similar manner via a blade root 119.

Between the spaced-apart platforms 118 of the guide vanes 114 of two adjacent rows of guide vanes, a respective ring segment 121 is arranged on the guide blade carrier 4 of the turbine unit 106. The outer surface of each ring segment 121 is in the radial direction from the outer end of the blades 112 lying opposite it spaced by a gap. The arranged between adjacent rows of stator ring segments 121 serve in particular as cover that protect the inner housing in the guide blade carrier 4 or other housing-mounting components from thermal overload by the turbine 106 flowing through the hot working medium M.

The combustion chamber 2 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. For this purpose, the combustion chamber 2 is configured in its entirety as an annular structure, which is positioned around the turbine shaft 108 around.

By using a guide vane system 1 of the above-mentioned embodiment in such a gas turbine 101, a significantly simplified repair can be achieved by a much simpler interchangeability of individual guide vanes 6, in particular the first turbine stage with high efficiency of the gas turbine 101.

Claims (13)

Guide vane system (1), in particular for a gas turbine (101), having a number of vane rows and a vane carrier (4),
wherein the guide blade carrier (4) is segmented in the region of a row of guide vanes,
wherein a segment (24) extends over the entire radial extent of the vane carrier (4) and the connection of the respective segment (24) with the rest of the vane carrier (26) is releasable. Guide vane system (1) according to claim 1,
in which the guide blade carrier (4) is segmented in the region of the row of guide vanes closest to a combustion chamber (2) of the gas turbine (101). Guide vane system (1) according to claim 1 or 2,
in which a plurality of segments (24) are provided which extend in their entirety over the entire circumferential direction of the vane support (4). Guide vane system (1) according to one of claims 1 to 3,
in which the respective connection is a screw connection and / or a tongue and groove connection. Guide vane system (1) according to one of claims 1 to 4,
in which a guide blade (6) of the respective guide blade row is releasably connected in the radial direction to the remaining guide blade carrier (26). Guide vane system (1) according to one of claims 1 to 5,
in which a guide blade (6) of the respective guide blade row is detachably connected to an inner ring (20) on its side facing the turbine axis (109). Guide vane system (1) according to claim 6,
in which the respective guide vane (6) comprises a spring (36) which can be inserted in a radial direction into a groove (38) of the inner ring (20). Guide vane system (1) according to claim 6 or 7,
wherein the inner ring (18) is connected to a combustion chamber hub (54). Guide vane system (1) according to one of claims 1 to 8,
wherein the segments (24) are connected to a combustion chamber wall (32). Guide vane system (1) according to one of claims 1 to 8,
in which a sealing plate (70) is provided between adjacent guide vanes (6) of the respective row of vanes, wherein bevels (72) are introduced at the sides of the blade root (10) and / or blade head (14) facing the adjacent guide blade (6), in which the sealing plate (70) by means of a clamping element (74) is fixed. Gas turbine (101) with a guide vane system (1) according to one of Claims 1 to 10. Gas turbine (101) according to claim 11, wherein in a outer housing of the gas turbine (101) a manhole is introduced. Gas and steam turbine power plant with a gas turbine (101) according to claim 1 or 12.

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