EP3000984A1 - Turbine vane adjustment device for a gas turbine - Google Patents

Abstract

The present invention relates to a vane adjusting device of a gas turbine with a plurality of each pivotable about a radial axis 33 vanes 20 which are arranged in at least one radial plane and with at least one Leitschaufelverstellring 29 which is coupled to the respective vanes 20 and by means of at least an actuating device is rotatable in the circumferential direction, wherein the Leitschaufelverstellring 29 is supported by means of a plurality of circumferentially distributed and mounted on the Leitschaufelverstellring 29 spacers 30 on a centrally disposed housing 38 in the radial direction, characterized in that on the Leitschaufelverstellring 29 for each spacer 30 from a a bushing 31 made of plastic with a high thermal expansion coefficient is fastened, on which the spacer 30 is mounted.

Description

The invention relates to a guide vane adjusting device for a compressor or a turbine of a gas turbine according to the preamble of claim 1.

The invention relates to a Leitschaufelverstellvorrichtung for a compressor or a turbine having a plurality of each pivotable about a radial axis guide vanes, which are arranged in at least one radial plane. The guide vanes thus form a disk-shaped arrangement, wherein upstream and downstream rotor blades are arranged in the flow direction, as is known from the prior art.

For adjusting the vanes of each disk-shaped arrangement of vanes, a Leitschaufelverstellring is provided, which is rotatable in the circumferential direction. The vane adjusting ring is coupled to the respective vane via a lever mechanism such that upon rotation of the vane adjusting ring, the vanes are pivoted about their radial axes. The vane adjusting ring is coupled to a suitable actuator.

Such arrangements are for example from the EP 2 258 926 A2 , of the US 2009/0162192 A1 or the US 2010/0278639 A1 previously known.

The Leitschaufelverstellring, which is rotatable for precise adjustment of the vanes by means of a drive mechanism in the circumferential direction relative to a housing is supported according to the prior art by means of spacers, which are arranged uniformly distributed around its circumference, against the housing and centered to this. During operation of the gas turbine, the housing heats up more than the Leitschaufelverstellring. This reduces the radial distance between the housing and the spacers connected to the vane adjusting ring. In order to avoid jamming due to different thermal expansions in operation between the spacers and the housing, according to the prior art between the spacers and the housing a game or Provided cold gap, which is present in the cold operating condition of the components. Due to these gaps or spacings of the spacers to the surface of the housing, both radial and tangential misalignments of the vane adjusting ring relative to the housing occur under certain operating conditions. This in turn leads to misalignment of the stator blades or vanes over the circumference of the vane assembly. This results in an incorrect setting of the vanes. Furthermore, the blade misalignment can lead to increased aerodynamic excitations of adjacent rotor and / or stator blades.

By means of the actuating device, it is thus possible to adapt the angle of attack of the respective guide vane to the operating conditions of the compressor or of the turbine. In the case of the devices known from the prior art, the disadvantage may arise that the adjustment of the guide vanes becomes imprecise due to thermal effects.

The invention has for its object to provide a Leitschaufelverstellvorrichtung for a compressor or a turbine of a gas turbine of the type mentioned above, which avoids the disadvantages of the prior art with a simple structure and simple, cost manufacturability and precise adjustment of the vanes, even with different thermal Expansions allows.

According to the invention the object is achieved by the combination of features of claim 1, the dependent claims show further advantageous embodiments of the invention.

According to the invention it is thus provided that on the Leitschaufelverstellring for each spacer a sleeve made of a plastic is attached, on which the spacer is mounted. The bush is made of a plastic material having a high thermal expansion coefficient. Due to the high thermal expansion, the spacer (centraliser) is moved radially outward by a greater amount during heating than the surrounding vane adjustment ring (unison ring). According to the invention, therefore, the radial expansion of the housing, which is stronger in comparison to the adjusting ring, can be compensated for during heating of the housing during operation by the spacer being moved radially outwards in accordance with this thermal expansion of the housing. These Radial movement is caused by the thermal expansion of the bush, which expands more than the vane adjusting ring. Thus, the sleeve pulls the spacer radially outward, adapted to the thermal expansion of the housing. A thermal expansion coefficient of the sleeve is thus higher than a thermal expansion coefficient of the Leitschaufelverstellrings. Thus, it is possible to keep the spacer always in contact or with a predetermined gap to the surface of the housing. This avoids that too large distances or gaps occur, which could lead to misalignments of Leitschaufelverstellrings. Likewise, it is prevented that the spacer jams on the surface of the housing, which leads to higher adjustment forces or to block the adjustment mechanism.

The amount of thermal expansion of the sleeve and thus the radial movement of the spacer can be adjusted according to the invention over the length of the socket, on the socket material and on the material of the spacer.

The solution according to the invention thus has the advantage that misalignments of the guide vanes or stator blades can be reduced or completely avoided. This leads to a more precise flow of both the vanes and the blades and thus to a lower fuel consumption. Furthermore, both the aerodynamic excitation of adjacent rotor and / or stator blades is reduced, and also reduces the adjustment of the adjustment by avoiding the jamming of the spacers on the housing.

In a particularly favorable embodiment of the invention, it is provided that the bushing is tube-like and that the spacer has a shaft which is fastened centrally in the bushing. The shaft can thus be stored at a suitable location in the socket, while the remaining length of the shaft in the socket in the radial direction (axial direction of the socket) can slide. Preferably, the shaft is attached to the radially outer portion of the sleeve, while the sleeve is preferably attached to a radially inner side of the Leitschaufelverstellrings to this or otherwise fixed.

To adjust the distance between the spacer and the surface of the housing, it is advantageous if the shaft is screwed to the socket. By a rotation of the shaft thus the gap between the spacer and the surface of the housing can be adjusted.

More preferably, the thermal expansion coefficient of the sleeve is higher than a thermal expansion coefficient, the spacer and / or a thermal expansion coefficient of the housing.

Preferably, the thermal expansion coefficient of the plastic bushing is at least twice as large as the thermal expansion coefficient of the vane adjusting ring and / or the spacer and / or the housing. The Leitschaufelverstellring, the spacer and the housing are preferably made of the same material, in particular of a high-strength steel alloy with α = 10/13 x 10 ^-6 mm / mmK or of a titanium alloy with α = 8/10 x 10 ^-6 mm / MMK. The bushing is preferably made of polyimide.

Fig. 1

zeigt eine schematische Darstellung eines Gasturbinentriebwerks gemäß der vorliegenden Erfindung,

Fig. 2

eine perspektivische Teilansicht eines Kompressors mit verstellbaren Leitschaufeln und Leitschaufelverstellringen,

Fig. 3

eine Detailansicht, analog Fig. 2,

Fig. 4

ein Ausführungsbeispiel der erfindungsgemäßen Lagerung des Abstandshalters in einer Radialschnittebene, und

Fig. 5

ein weiteres Ausführungsbeispiel in perspektivischer Schnittansicht.

In the following the invention will be described by means of an embodiment in conjunction with the drawing. Showing:

Fig. 1

shows a schematic representation of a gas turbine engine according to the present invention,

Fig. 2

a partial perspective view of a compressor with adjustable vanes and Leitschaufelverstellringen,

Fig. 3

a detailed view, analog Fig. 2 .

Fig. 4

an embodiment of the inventive storage of the spacer in a radial section plane, and

Fig. 5

a further embodiment in a perspective sectional view.

The gas turbine engine 10 according to Fig. 1 is an example of a turbomachine to which the invention may find application. However, it will be understood from the following that the invention can be used with other turbomachinery as well. The engine 10 is formed in a conventional manner and comprises in succession an air inlet 11, a fan 12 circulating in a housing, a medium pressure compressor 13, a high pressure compressor 14, combustion chambers 15, a high pressure turbine 16, a medium pressure turbine 17 and a low pressure turbine 18 and an exhaust nozzle 19, which are all arranged around a central engine axis 1.

The intermediate-pressure compressor 13 and the high-pressure compressor 14 each comprise a plurality of stages, each of which has a circumferentially extending array of fixed stationary vanes 20, commonly referred to as stator vanes, extending radially inward from the engine casing 21 in an annular flow passage through the compressors 13, 14 protrude. The compressors further include an array of compressor blades 22 projecting radially outwardly from a rotatable drum or disc 26 coupled to hubs 27 of high pressure turbine 16 and mid pressure turbine 17, respectively.

The turbine sections 16, 17, 18 have similar stages, including an array of vanes 23 projecting radially inward from the housing 21 into the annular flow passage through the turbines 16, 17, 18, and a subsequent arrangement of turbine blades 24 following projecting externally from a rotatable hub 27. The compressor drum or compressor disk 26 and the vanes 22 disposed thereon and the turbine rotor hub 27 and the turbine blades 24 disposed thereon rotate about the engine axis 1 during operation.

The invention will be described below with reference to a compressor, but it is also applicable to vanes of a turbine.

The Fig. 2 shows a partial perspective view of a compressor with multiple rows of adjustable vanes 20, between each of which compressor blades 22 are arranged. The individual vanes 20 are each pivotable about a radial axis 33. They are connected to a lever 34 which is rotatably coupled at its opposite end portion with a Leitschaufelverstellring 29. By a rotation of the Leitschaufelverstellrings 29 in the circumferential direction is a pivoting of the individual lever 34. This causes a rotation of the vanes 20 about the respective axis 33 causes.

An actuating device, not shown, which is formed for example as a piston-cylinder unit is coupled via a coupling rod (not shown) with a crankshaft 36, as in Fig. 3 is shown. The crankshaft 36 is supported by bearings 37. The crankshaft 36 is further coupled by means of coupling rods 35 with the Leitschaufelverstellringen 29. An actuation of the actuating device thus leads to a rotation or pivoting of the crankshaft 36, which in turn leads to a rotation of the respective Leitschaufelverstellrings 29, since the crankshaft 36 is connected via a coupling rod 35 with the Leitschaufelverstellring 29.

The Fig. 3 further shows a plurality of spacers 30 distributed around the circumference, which (see also the below-described FIGS Fig. 4 ) have a shaft 32 which is adjustably mounted on the Leitschaufelverstellring 29. The spacer abuts the surface of the housing 38 and is moved together with the Leitschaufelverstellring 29 in the circumferential direction. The spacer centers the vane adjusting ring 29 in the radial direction relative to the housing 38 Fig. 3 has the housing 38 at the areas where the spacer 30 abuts, suitable pedestals or contact surfaces or the like.

The Fig. 4 shows an embodiment of the inventive solution in detail in a sectional view of a radial plane. In this case, the housing 38 is shown only schematically and has over the spacer 30 an oversized for the purpose of clarity on distance.

At the Leitschaufelverstellring 29 a made of a plastic material bushing 31 is mounted. This bush is in the form of a sleeve and has a central recess in which the shaft 32 of the spacer 30 is mounted is. The bearing of the shaft 32 takes place at a radially outer region of the bushing 31 by means of a thread 39. By rotation of the shaft 32, it is thus possible to adjust the radial position of the spacer 30.

The Fig. 4 shows a schematic representation to illustrate the executed by the thermal expansions radial movements. It is assumed, for example, from a heating with a value of .DELTA.T = 70 K. In such a heating of the housing 38 (in this example high-strength steel alloy with α = 10/13 x 10 ^-6 mm / mmK, alternatively also titanium alloys possible with α = 8/10 x 10 ^-6 mm / mmK), the housing expands the example shown radially by 0.3 mm. The plastic material of the bush 31 with α = 20/50 x 10 ^-6 mm / mmK would thereby expand by an amount of 0.42 mm. The shaft 32 and the adjusting ring 29 undergo a total length change of 0.08 mm (expansion coefficient α = 10/13 x 10 ^-6 mm / mmK). This results in a total radial movement of the spacer 30 outwardly of 0.34 mm. This means that the distance between the spacer 30 and the surface of the housing 38 remains substantially constant, so that even with this increase in the temperature of the Leitschaufelverstellring 29 is precisely centered.

The Fig. 5 shows a further embodiment, wherein like parts are provided with the same reference numerals. The shank 32 has a thread at its end and is adjustably secured by means of a nut 40, which is connected to the bush 31.

LIST OF REFERENCE NUMBERS

1

Engine axis

10

Gas turbine engine

11

air intake

12

in the housing revolving fan

13

Medium pressure compressor

14

High pressure compressor

15

combustors

16

High-pressure turbine

17

Intermediate pressure turbine

18

Low-pressure turbine

19

exhaust nozzle

20

vanes

21

Engine casing

22

Compressor blades

23

vanes

24

turbine blades

26

Compressor drum or disc

27

Turbinenrotornabe

28

outlet cone

29

Leitschaufelverstellring

30

spacer

31

Rifle

32

shaft

33

axis

34

lever

35

coupling rod

36

crankshaft

37

camp

38

casing

39

thread

40

mother

Claims (11)

Guide vane adjusting device of a gas turbine with a plurality of each about a radial axis (33) pivotable vanes (20) which are arranged in at least one radial plane and with at least one Leitschaufelverstellring (29) which is coupled to the respective vanes (20) and means at least one actuating device is rotatable in the circumferential direction, wherein the Leitschaufelverstellring (29) by means of a plurality of circumferentially distributed and on the Leitschaufelverstellring (29) mounted spacer (30) on a centrally disposed housing (38) is supported in the radial direction, characterized in that at the vane adjusting ring (29) for each spacer (30) is fixed a bushing (31) made of a plastic having a coefficient of thermal expansion higher than a coefficient of thermal expansion of the vane adjusting ring (29) on which the spacer (30) is mounted. Guide vane adjusting device according to claim 1, characterized in that the bush (31) is tube-like and that the spacer has a centrally in the bushing (31) fixed shaft (32). Guide vane adjusting device according to claim 2, characterized in that the shaft (32) is fixed to the radially outer region of the bushing (31). Guide vane adjusting device according to one of claims 2 or 3, characterized in that the shaft (32) with the bush (31) is screwed. Guide vane adjusting device according to one of claims 1 to 4, characterized in that the bushing (31) on the radially inner side of the Leitschaufelverstellrings (29) is attached thereto. Guide vane adjusting device according to one of claims 2 to 5, characterized in that the shaft (32) relative to the bush (31) is adjustable in the radial direction. Guide vane adjusting device according to one of claims 2 to 6, characterized in that the shaft (32) made of a metallic material having a similar or equal thermal expansion coefficient as the housing (38) and / or the Leitschaufelverstellring (29) is made. Guide vane adjusting device according to one of the preceding claims, characterized in that the coefficient of thermal expansion of the bushing (31) is greater than a thermal expansion coefficient of the spacer (30) and / or the housing (38). Guide vane adjusting device according to claim 8, characterized in that the thermal expansion coefficient of the bushing (31) is at least twice as large as the thermal expansion coefficient of Leitschaufelverstellrings (29) and / or the spacer (30) and / or the housing (38). Guide vane adjusting device according to one of the preceding claims, characterized in that the bush (31) is made of polyimide. A vane adjusting device according to any one of the preceding claims, characterized in that the vane adjusting ring (29) and the spacer (30) and the housing (38) are made of a high strength steel alloy or a titanium alloy.

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