DE102011014292A1 - Intermediate level sealing ring for gas turbine engine, is made of metal foam, and has element, which is made of wear-resistant material that is arranged in metal foam, where inner platform is provided for supporting guide vanes - Google Patents

Abstract

The Intermediate level sealing ring is made of a metal foam, and has an element, which is made of a wear-resistant material that is arranged in the metal foam. An inner platform is provided for supporting guide vanes. A radial inner ring (28) is provided, which is positioned directly on the platform. The sealing elements are provided in a single piece manner. An annular profile element (31) is provided, which is made of a wear-resistant material. An independent claim is included for a method for manufacturing of Intermediate level sealing ring.

Description

The invention relates to an interstage seal ring of a gas turbine and a method for producing an interstage seal ring. Furthermore, the invention relates to an interstage seal of a gas turbine using the interstage seal of the invention.

Interstage seals in gas turbines usually consist of a forged and finished turned ring into which several pins for centering the seal (via radial grooves in the static vanes) are pressed and welded to the fuse. Since relative movements occur between the static guide vanes and the sealing ring during operation, a U-shaped thin-walled sheet metal structure made of wear-resistant material is usually provided between these components. The ring also serves as a support for an inlet layer, which is applied either by thermal plasma spraying or soldered in the form of a honeycomb ring.

In another known from the prior art embodiment of an intermediate stage seal provide additional edge sealing arms for improved sealing effect and provide improved protection against hot gas intake. The edge seals are designed so that no contact with rotating parts can occur.

Interstage seals with integral pre-drilled holes are also known which efficiently supply the downstream rotating blade with cooling air. In addition, an improved sealing effect under all operating conditions is achieved by an inlet structure located inside and outside of the rotating sealing arm (so-called crocodile seal).

The production of the sealing ring from a forged ring requires relatively high material usage, of which less than 10% material remains after finishing. This causes high costs.

The pins must be welded to the seal ring to prevent loss. This causes costs, a delay of the component and limits the choice of materials.

The wearguards must be connected by forming during assembly with the sealing ring. In order to carry out a non-destructive crack test during the overhaul, the installed wear protection plates must be removed and replaced with new parts after the crack test.

The application of the run-in layer requires an additional manufacturing step and thus costs.

In the version with additional edge sealing arms, the vibration behavior must be analyzed and the wall thickness increased if necessary, which leads to additional weight.

In the version with integrated pre-drilled holes, their production is relatively complicated, since they have to be drilled at a relatively shallow angle (15 ° to 40 °) relative to the component surface.

If the interstage seal is executed as a crocodile seal, the seal diameter must be elaborately prepared by the erosion process, since grinding is not possible because of the lack of accessibility.

The invention has for its object to provide an intermediate stage sealing ring of a gas turbine and a method for its production, wherein a simple, cost-effective production is possible and the intermediate stage sealing ring has advantageous mechanical properties.

According to the invention the object is achieved by the combination of features of the independent claims, the subclaims show further advantageous embodiments of the invention.

According to the invention it is thus provided that the intermediate stage sealing ring is made of a metal foam. Here, it is possible to realize the final shape with sufficient accuracy, so that only a small amount of reworking is required. The metal foam material results in a low weight with high rigidity. By using a uniformly foamed corrosion-resistant high-temperature alloy such. As Hastalloy X, IN 601, ODS alloys, the above requirements are met in an excellent manner. In this case, the metal foam technology is generally known to the person skilled in the art. Here, a suitable metal alloy - in the present invention is, for example, a metallic corrosion-resistant high-temperature alloy - foamed by known methods, so that forms a substantially fine foam structure, with thin metal walls include a plurality of cavities between them. In such a Aufschäummethode, for example, a metal powder can be mixed with a Metallhydrit and then extruded, after which this precursor is thermally foamed. Alternatively, a corresponding preparation of prefabricated metallic hollow spheres is possible. In general, this is a primarily Closed pore foamed structure with high porosity and good thermal insulation properties formed.

The intermediate stage seal according to the invention consists of a ring-shaped U-profile made of wear-resistant material, produced by roll forming or other suitable manufacturing methods (eg extruding), into which bores for receiving centering pins are inserted. The centering pins are only pressed into the ring and aligned if necessary. This assembly is placed in a mold for the production of the metal foam and goes through the necessary processes. In general, then only the seal diameter must be machined relative to serving as a reference centering pins. The metal foam forms a positive connection with the rest of the structure in addition to the compound of the materials produced by sintering by diffusion. At the same time, the centering pins are secured against falling out by the metal foam.

A further embodiment additionally includes the integration of edge seal arms in the metal foam structure. Finally, pre-whirl nozzles in the form of tubes can be "cast in" and a crocodile seal can be realized.

• – Hohe Materialausnutzung, nur Dichtflächen müssen spanend bearbeitet werden, hierdurch ergeben sich geringe Herstellkosten;
• – Entfall der Schweiß- und Lötprozesse, hierdurch ergeben sich geringe Herstellkosten, freie Werkstoffwahl;
• – In der Ausführung mit Randdichtungsarmen kann eine höhere (Form-)Steifigkeit der Dichtungsarme bei geringerem Gewicht erzielt werden;
• – In der Ausführung mit integrierten Vordralldüsen entfällt das aufwendige Bohren;
• – Abhängig vom Schaummaterial können die Dichtungsdurchmesser durch Standard-Drehoperationen hergestellt werden (besonders ein Vorteil bei Krokodildichtungen); Bei vergleichbarer Steifigkeit kann generell Gewicht eingespart werden;
• – In der Ausführung mit Randdichtungsarmen können auch diese eventuell als einlaufende Dichtungen ausgeführt werden, hierdurch ergeben sich eine verbesserte Dichtwirkung und damit geringere Sekundärluftverluste;
• – Die geringere Wärmeleitfähigkeit des Metallschaums kann zu einem besseren zeitlichen Ausdehnungsverhalten der Zwischenstufendichtung führen, hierdurch ergeben sich eine verbesserte Dichtwirkung und damit geringere Sekundärluftverluste;
• – Es können weitere Konstruktionselemente wie Sekundärluftkanäle integriert werden.

According to the invention, there are, inter alia, the following advantages:

• - High material utilization, only sealing surfaces must be machined, this results in low production costs;
• - elimination of welding and soldering processes, this results in low production costs, free choice of materials;
• - In the version with edge sealing arms, a higher (form) stiffness of the sealing arms can be achieved with less weight;
• - In the version with integrated pre-whirl nozzles eliminates the costly drilling;
• Depending on the foam material, the seal diameter can be made by standard turning operations (especially an advantage in crocodile seals); With comparable stiffness weight can generally be saved;
• - In the version with edge sealing arms also these may possibly be designed as incoming seals, this results in an improved sealing effect and thus lower secondary air losses;
• - The lower thermal conductivity of the metal foam can lead to a better time expansion behavior of the interstage seal, this results in an improved sealing effect and thus lower secondary air losses;
• - Other design elements such as secondary air ducts can be integrated.

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

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

2 a partial-axial sectional view of a known from the prior art interstage seal,

3 another view of a known from the prior art construction of an interstage seal,

4 a partial-axial sectional view of a first embodiment of an intermediate stage seal ring according to the invention,

5 a modified embodiment in an analogous representation to 4 , and

6 a part-sectional view, analogous to 4 and 5 , Another embodiment of the invention.

The 1 shows a schematic representation of a gas turbine engine according to the present invention.

The gas turbine engine 10 according to 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 one air inlet in succession in the flow direction 11 , a circulating in a housing fan 12 , an intermediate pressure compressor 13 , a high pressure compressor 14 , Combustion chambers 15 , a high-pressure turbine 16 , an intermediate-pressure turbine 17 and a low-pressure turbine 18 and an exhaust nozzle 19 all around a central engine axis 1 are arranged.

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

The turbine sections 16 . 17 . 18 have similar steps, comprising an array of fixed vanes 23 extending radially inward from the housing 21 into the annular flow channel through the turbines 16 . 17 . 18 project, and a subsequent arrangement of turbine blades 24 facing outward from a rotatable hub 27 protrude. The compressor drum or compressor disk 26 and the blades arranged thereon 22 as well as the turbine rotor hub 27 and the turbine blades disposed thereon 24 rotate around the engine axis during operation 1 ,

The 2 shows a known from the prior art construction of an interstage seal. The 2 shows a foot portion of a vane 30 , which with a radially inner platform 29 connected is. This has a footbridge 36 which is aligned radially inwardly and is formed as an annular segment. The intermediate stage sealing ring 28 becomes of several webs 36 held, with the centering pins 32 engage in corresponding grooves in the webs and thus the intermediate stage sealing ring 28 center and secure against twisting. Between the jetty 36 and the radially inner ring 28 is a wear-resistant element 31 , which is designed as an annular profile element arranged. At the in 2 shown construction is radially inward on the interstage seal ring 28 an enema layer 37 educated.

The 3 shows a modified construction in which the interstage seal ring 28 with a rim sealing arm 33 is provided, a Vordralldüse 34 has and radially inwardly with seal arms 35 for a crocodile seal 38 is provided.

The embodiment according to the invention 4 shows an annular profile element 31 of a wear resistant material made by roll forming or other suitable manufacturing process, for example extrusion. The annular profile element 31 has recesses distributed around the circumference, into which centering pins 32 are inserted. The arrangement of the annular profile element 31 and the centering pins 32 becomes the formation of the interstage seal ring according to the invention 28 coated with metal foam or embedded in metal foam.

The 5 shows a modified embodiment in which two lateral edge seal arms 33 are provided.

In the in the 4 and 5 As shown embodiments, it is possible to provide an inlet layer, analog 2 , Preferably, the metal foam itself represents the inlet layer, which can be dispensed with a separate inlet layer.

The 6 shows a further embodiment of the invention, in which additionally Vorralldüsen 34 embedded in the metal foam material. These are designed in the form of tubes, so that they are exactly positioned on the one hand with respect to their central axis and on the other hand do not need to be reworked. Furthermore, the shows 6 in that sealing arms in this embodiment 35 for a crocodile seal 38 are formed from the metal foam material.

LIST OF REFERENCE NUMBERS

1

Engine axis

10

Gas turbine engine

11

air intake

12

in the housing revolving fan

13

Intermediate 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

Interstage seal ring / radially inner ring

29

(Vane) Platform

30

vane

31

Wear-resistant element / annular profile element

32

Centering

33

Randdichtungsarm

34

Vordralldüse

35

Sealing arm of a crocodile seal

36

web

37

running-in layer

38

crocodile seal

Claims (11)

Intermediate seal of a gas turbine, characterized in that it is made of a metal foam. Intermediate seal according to claim 1, characterized in that in the metal foam at least one element ( 31 ) is arranged made of wear-resistant material. Method for producing an intermediate stage sealing ring ( 28 ) of a gas turbine, wherein an annular profile element ( 31 ) is made of a wear-resistant material, in which recesses for receiving centering pins ( 32 ) and subsequently centering pins ( 32 ) are used, wherein the profile element ( 31 ) is subsequently introduced into a mold and coated with metal foam. A method according to claim 3, characterized in that the interstage seal ring ( 28 ) is machined after the casing with metal foam. A method according to claim 3 or 4, characterized in that the sheath with the metal foam comprises a sintering process. Method according to one of claims 3 to 5, characterized in that the interstage seal ring ( 28 ) when sheathing with the metal foam with edge seal arms ( 33 ) and / or pre-whirl nozzles ( 34 ) and / or sealing arms ( 35 ). Method according to claim 6, characterized in that the pre-whirl nozzles ( 34 ) are manufactured as separate elements and embedded in the sheathing with the metal foam in these. Method according to one of claims 3 to 7, characterized in that the annular profile element ( 31 ) is produced by rolling, forming or extruding and / or that the centering pins ( 32 ) in the profile element ( 31 ) and / or adjusted to this position. Interstage seal ring of a gas turbine with an inner platform ( 29 ), which vanes ( 30 ), and with a radially inner ring ( 28 ), which directly at the platform ( 29 ), characterized in that the radially inner ring ( 28 ) is formed as an intermediate stage sealing ring according to one of claims 1 to 8. Intermediate seal according to claim 9, characterized in that it is integral with sealing elements ( 33 . 35 ) is provided. Intermediate seal according to one of claims 1 to 10, characterized in that the metal foam forms an inlet lining.

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