EP4151836A2 - Heat protection element for a bearing chamber of a gas turbine - Google Patents

Abstract

Described is a heat protection element (50) for a gas turbine (10), in particular an aircraft gas turbine, which is set up to at least partially surround a bearing chamber (60) of the gas turbine (10).
at least one connecting section (52) arranged in an axially front area (VB), which can be connected or is connected in a material-locking manner to a protective element (54) of a seal carrier, in particular a seal carrier with a carbon seal,
at least one support section (58) arranged in an axially central region (MB), which is set up to support the heat protection element (50) radially on the bearing chamber (60),
an end section (64) arranged in an axially rear area (HB), which forms a free end (66) of the heat protection element (50) and is shaped in such a way that the end section (64) surrounds the bearing chamber (60) without contact.

Description

The present invention relates to a heat protection element for a gas turbine, in particular an aircraft gas turbine, which is set up to at least partially surround a bearing chamber of the gas turbine. Furthermore, the invention relates to a heat protection unit and a gas turbine with a heat protection element.

Directional information such as “axial” or “axial”, “radial” or “radial” and “circumferential” are to be understood in relation to the machine axis of the gas turbine, unless the context explicitly or implicitly states otherwise. Furthermore, statements such as axially in front or axially behind are to be understood in relation to the usual main flow direction of gas in the gas turbine, unless something else is explicitly stated from the context.

Bearing chambers in axially rear parts or areas of a gas turbine, in particular aircraft gas turbine, must be insulated from hot cavities in the gas turbine in order not to exceed a permissible temperature of circulating coolants, such as oil or the like. For this purpose it is known to blow cooling air or sealing air into the cavity and/or to insulate the cavities by means of heat protection elements.

In a common design, a bearing chamber is surrounded in the circumferential direction by a radially outer heat shield and a radially inner heat shield. The radially inner heat shield is designed in two parts with a front and a rear heat protection shield, with both the front heat protection shield and the rear heat protection shield being materially connected to the bearing chamber, in particular welded or soldered. Due to the material connection, the inner heat protection shield cannot be removed from the storage chamber. This gives rise to the problem that the storage chamber cannot be inspected, or can only be inspected with difficulty. Furthermore, it has been shown that fretting can occur in particular at the connection points of the rear heat shield with the highly stressed bearing chamber.

The following publications are referred to as examples of the technological background: US20190249569A1 , US9605551B2 and US10415481B2 , heat protection shields for gas turbines being known from these publications only in general, but no heat protection shields specifically arranged around a storage chamber.

The object on which the invention is based is seen as specifying a heat shield element for a gas turbine in which the above disadvantages can be avoided.

This object is achieved by a heat shield element, a heat shield unit and a gas turbine having the features of the respective independent patent claims. Possible advantageous configurations are contained in the dependent patent claims.

• wenigstens einem in einem axial vorderen Bereich angeordneten Verbindungabschnitt, der materialschlüssig mit einem Schutzelement eines Dichtungsträgers, insbesondere eines Dichtungsträgers mit einer Kohledichtung, verbindbar oder verbunden ist,
• wenigstens einem in einem axial mittleren Bereich angeordneten Abstützabschnitt, der dazu eingerichtet ist, das Hitzeschutzelement radial an der Lagerkammer abzustützen, und einem in einem axial hinteren Bereich angeordneten Endabschnitt, welcher ein freies Ende des Hitzeschutzelements bildet und derart geformt ist, dass der Endabschnitt die Lagerkammer kontaktlos umgibt.

A heat protection element for a gas turbine, in particular an aircraft gas turbine, which is set up to at least partially surround a bearing chamber of the gas turbine, is therefore proposed

• at least one connecting section arranged in an axially front area, which can be connected or is connected in a material-locking manner to a protective element of a seal carrier, in particular a seal carrier with a carbon seal,
• at least one support section arranged in an axially middle area, which is designed to support the heat protection element radially on the bearing chamber, and one end section arranged in an axially rear area, which forms a free end of the heat protection element and is shaped in such a way that the end section forms the bearing chamber surrounded without contact.

Such a configuration of the heat protection element can prevent fretting-causing contact between the heat protection element and the bearing chamber in the axially rear region. A distance of a few millimeters is formed between the end section and the storage chamber. Such a heat protection element thus enables good thermal shielding of the bearing chamber in its axially rear region, despite the contactless arrangement.

The heat protection element can be designed in one piece. In other words, in a departure from previous heat protection elements, a one-piece or one-piece heat protection element arranged radially on the inside is proposed so that there is no longer any multiple parts and in particular a material-locking connection of an axially rear heat protection element can be dispensed with.

The heat protection element can be designed in such a way that it forms a heat protection unit together with the protection element of the seal carrier Flange portion of the storage chamber is fastened or fastened. In particular, the heat protection unit can be connected to the flange section of the bearing chamber by means of screw connections running in the axial direction.

The heat protection element or the heat protection unit can be pushed onto the bearing chamber from the axial front or be removable from it. Thus, when inspecting the gas turbine, the heat protection element surrounding the bearing chamber or the heat protection unit can be separated from the bearing chamber so that it can be inspected. In particular, this also enables a simplified replacement of a heat protection element or a heat protection unit.

In the case of the heat protection element, at least three tab-like connecting sections distributed in the circumferential direction can be formed in the axially front area. By means of these strap-like connecting sections, a type of punctiform, material-locking connection between the heat protection element and the protection element of the seal carrier can be made possible.

Alternatively, a single circumferential connection section can be formed in the axially front area of the heat protection element, in particular in the form of a circumferential welded or soldered seam. Furthermore, it is also conceivable that a connection is made by means of a press joint between the heat protection element and the protection element of the seal carrier.

In the case of the heat protection element, the end section can be bent over axially to the front, in particular bent over in the manner of a rim. Sufficient stability or rigidity of the end section can be achieved by such a reshaping of the end section, so that its non-contact arrangement in relation to the bearing chamber can be reliably ensured, in particular also during operation of the gas turbine and under corresponding thermal or mechanical loading.

In the case of the heat protection element, at least three beads which are distributed in the circumferential direction and are shaped radially inward can be formed in the axially central region, which beads serve as respective support sections. It is of course also conceivable that more than three beads are provided. Furthermore, it is also conceivable that a continuous bead in the circumferential direction is formed.

As an alternative to this, a single circumferential support section can be provided in the axially central region, which can be or is in contact with a ring seal arrangement supported on the bearing chamber, in particular a sealing cord. Such a ring seal arrangement can be accommodated, for example, in a groove-like recess provided on the outer circumference of the bearing chamber. In such a configuration, the support section on the heat protection element can also be designed without a special shape, in particular axially straight.

Also proposed is a heat protection unit for a bearing chamber of a gas turbine, in particular an aircraft gas turbine, consisting of a heat protection element as described above and a further protection element of a seal carrier which is materially connected to the heat protection element in an axially front area of the heat protection unit. Optional configurations of the heat protection element described above can also be implemented or used for the heat protection unit.

The further protective element of the seal carrier can in particular be an essentially ring-shaped sleeve which surrounds and thermally shields a seal carrier for a carbon seal. In this case, the carbon seal serves in particular to provide a seal with respect to a shaft of the gas turbine.

Furthermore, a gas turbine, in particular an aircraft gas turbine, is proposed with at least one bearing chamber around which a heat protection element described above or a heat protection unit described above is arranged. The heat protection element can be provided in the area of a turbine center frame or as part of a turbine center frame.

• Fig. 1 zeigt in einer vereinfachten, schematischen Darstellung ein Prinzipbild einer Fluggasturbine.
• Fig. 2 zeigt in einer vereinfachten, schematischen Perspektivdarstellung ein Hitzeschutzelement bzw. eine Hitzeschutzeinheit.
• Fig. 3 zeigt eine vereinfachte, schematische Schnittdarstellung einer Lagerkammer und eines Hitzeschutzelements etwa entsprechend der Schnittlinie III-III der Fig. 2.
• Fig. 4 zeigt eine vereinfachte, schematische und vergrößerte Schnittdarstellung eines axial mittleren und hinteren Bereichs des Hitzeschildelements und der Lagerkammer, etwa entsprechend dem in Fig. 3 mit dem Rechteck IV gekennzeichneten Bereich.

The invention is described below by way of example and not by way of limitation with reference to the attached figures.

• 1 shows a basic diagram of an aircraft gas turbine in a simplified, schematic representation.
• 2 shows a heat protection element or a heat protection unit in a simplified, schematic perspective illustration.
• 3 shows a simplified, schematic sectional view of a storage chamber and a heat protection element approximately along line III-III of FIG 2 .
• 4 shows a simplified, schematic and enlarged sectional view of an axially middle and rear region of the heat shield element and the bearing chamber, corresponding approximately to that in 3 area marked with rectangle IV.

1 shows a schematic and simplified view of an aircraft gas turbine 10, which is illustrated purely by way of example as a turbofan engine. The gas turbine 10 includes a fan 12 surrounded by a jacket 14 that is indicated. In the axial direction AR of the gas turbine 10, the fan 12 is followed by a compressor 16, which is accommodated in an indicated inner housing 18 and can be of single-stage or multi-stage design. The compressor 16 is followed by the combustion chamber 20 . Hot exhaust gas flowing out of the combustion chamber then flows through the adjoining turbine 22, which can be of single-stage or multi-stage design. In the present example, the turbine 22 includes a high-pressure turbine 24 and a low-pressure turbine 26. A hollow shaft 28 connects the high-pressure turbine 24 to the compressor 16, in particular a high-pressure compressor 29, so that they are driven or rotated together. A further inner shaft 30 in the radial direction RR of the turbine connects the low-pressure turbine 26 to the fan 12 and to a low-pressure compressor 32, so that they are driven or rotated together. A thrust nozzle 33 , which is only indicated here, is connected to the turbine 22 .

In the illustrated example of an aircraft gas turbine 10, a turbine center frame 34 is arranged between the high-pressure turbine 24 and the low-pressure turbine 26, which is arranged around the shafts 28, 30. In its radially outer region 36 , hot exhaust gases from the high-pressure turbine 24 flow through the turbine center frame 34 . The hot exhaust gas then reaches an annular space 38 of the low-pressure turbine 26. Rotor blade rings 27 of the compressors 28, 32 and the turbines 24, 26 are shown by way of example. For reasons of clarity, guide vane rings 31 that are usually present are shown as an example only for compressor 32 .

2 shows a heat protection element 50, which can be used in a gas turbine 10, in a simplified, schematic perspective representation. In the 2 an axis of rotation DA is indicated, which is aligned with the axes of the shafts 28, 30 ( 1 ) of the gas turbine coincide. The heat protection element 50 is arranged in the area of a storage chamber in which at least one shaft 28, 30 of the gas turbine is mounted. Referring to 1 the heat protection element 50 can be arranged in particular in the region of the turbine center frame 34, in particular radially on the inside of the in 1 shown outer region 36 in which hot gas flows.

The heat protection element 50 has at least one connection section 52 in an axially front area VB. The connection section(s) 52 are materially connected to a protective element 54 . The protective element 54 surrounds or covers a seal carrier, not shown here. Starting from the connection to the protective element 54, the heat protective element 50 has a main body 56 which extends axially to the rear and has different radii over the axial length. In particular, the radius of the heat protection element 50 increases discretely or continuously in sections from the axial front to the axial rear.

For the further description of the heat protection element 50, the sectional views of FIG 3 and 4 referenced.

A support section 58 is provided in an axially central area MB, which is set up to support the heat protection element 50 radially on a bearing chamber 60 shown in simplified form in the sectional illustrations. The support of the heat protection element 50 can be done via a support element 62 in the 3 and 4 is shown only schematically and representative of different types of support.

In an axially rear area HB, the heat protection element 50 has an end section 64 which forms a free end 66 of the heat protection element 50 . The end section 64 is shaped or bent over in such a way that the end section 64 surrounds the bearing chamber 60 in a contactless manner. In other words, a distance AB or intermediate space is formed between the end section 64 and the bearing chamber 60 .

That in the Figures 2 to 4 Heat protection element 50 shown can be formed in one piece. The connection sections 52, support section 58 and end section 64 described above are therefore produced from one workpiece or material.

The heat protection element 50 forms a heat protection unit 70 together with the protection element 54 of the seal carrier. The heat protection unit 70 can be attached to an axially front flange section 72 which is 3 is only indicated, the storage chamber 60 can be fastened or fastened. The heat protection unit 70 can, for example, be pushed onto the bearing chamber 60 from the axial front or removed from it.

In the axially front region VB, for example, at least three strap-like connecting sections 52 can be formed, distributed in the circumferential direction. Such a configuration is exemplified by the 2 visible, with only two of several connecting sections 52 are shown.

Alternatively, the heat protection element 50 can have a single circumferential connection section 52 in the axially front region VB, in particular in the form of a circumferential welded or soldered seam.

How from the Figures 2 to 4 As can be seen, the end section 64 of the heat protection element 50 is bent forward axially. The end portion 64 can also be described as being bent over like a brim. Such a reshaping of the end section 64 can achieve sufficient stability or rigidity of the end section 64 so that its non-contact arrangement (with distance BA or intermediate space) in relation to the bearing chamber 60 can be reliably ensured, in particular also during operation of the gas turbine 10 and under corresponding thermal or mechanical stress.

The above-mentioned, schematically and representatively illustrated support element 62 can, according to embodiments, be designed in such a way that in the axial central region MB at least three beads are formed on heat protection element 50, distributed in the circumferential direction and shaped radially inwards, which act as respective support sections 58 or support element 62 serve.

Alternatively, a single circumferential support section 58 can be provided in the axially central area MB, which can be or is in contact with a ring seal arrangement, in particular a sealing cord, supported on the bearing chamber 60 . In other words, the support element 62 shown can also be understood as such a ring seal arrangement or represent such.

The heat protection unit 70 can, for example, be screwed to the storage chamber 60, which is achieved by the in 2 visible holes 74 in the protective element 54 is illustrated.

With regard to the axial areas VB, MB, HB, it is pointed out that these can be established or defined, for example, based on a percentage of the axial length of the heat protection element 50 . Related to the 3 the front and rear areas VB, HB are each illustrated with approximately 20% of the axial extension of the heat protection element 50, with the central area MB being at approximately 60%. This percentage distribution is purely exemplary; in particular, the front and rear areas VB can also be defined shorter or longer, for example in a range of approximately 5% to 30% of the axial extension of the heat protection element 50. This results in the middle area MB can be about 40% to 90% of the axial extension.

A configuration of the heat protection element 50 presented above makes it possible to avoid contact between the heat protection element 50 and the bearing chamber 60 that causes fretting in the axially rear area HB. In this case, the distance AB or intermediate space is formed between the end section 64 and the bearing chamber 60 . This distance AB can be a few millimeters. Despite the non-contact arrangement in its axially rear region HB, the heat protection element 50 presented here enables good thermal shielding of the bearing chamber 60. Due to the one-piece design of the heat protection element 50, in contrast to previous heat protection elements, a one-piece or one-piece heat protection element 50 arranged radially on the inside is described , so that there is no longer a multi-part design and in particular a material-locking connection of an axially rear heat protection element can be dispensed with.

reference list

10

aircraft gas turbine

12

fan

14

Coat

16

compressor

18

inner casing

20

combustion chamber

22

turbine

24

high pressure turbine

26

low pressure turbine

28

hollow shaft

29

high-pressure compressor

30

Wave

31

vane ring

32

low-pressure compressor

33

thruster

34

turbine center frame

36

radially outer area

38

annulus

50

heat protection element

52

connection section

54

protective element

56

main body

58

support section

60

storage chamber

62

support element

64

end section

66

free end

70

heat protection unit

72

flange section

74

drilling

AWAY

distance or space

AR

axial direction

RR

radial direction

hb

axial rear area

MB

axial middle area

vb

axial front area

Claims (12)

Heat protection element (50) for a gas turbine (10), in particular an aircraft gas turbine, which is set up to at least partially surround a bearing chamber (60) of the gas turbine (10). at least one connecting section (52) arranged in an axially front area (VB), which can be connected or is connected in a material-locking manner to a protective element (54) of a seal carrier, in particular a seal carrier with a carbon seal, at least one support section (58) arranged in an axially central region (MB), which is set up to support the heat protection element (50) radially on the bearing chamber (60), an end section (64) arranged in an axially rear area (HB), which forms a free end (66) of the heat protection element (50) and is shaped in such a way that the end section (64) surrounds the bearing chamber (60) without contact. The heat protection element (50) according to claim 1, wherein it is formed in one piece. Heat protection element (50) according to claim 1 or 2, wherein it is designed in such a way that together with the protection element (54) of the seal carrier it forms a heat protection unit (70) which can be fastened to an axially front flange section (72) of the bearing chamber (60) or is attached. Heat protection element (50) according to Claim 3, in which the heat protection unit (70) can be pushed onto the bearing chamber (60) or removed from it from the axial front. Heat protection element (50) according to one of the preceding claims, wherein at least three strap-like connecting sections (52) distributed in the circumferential direction are formed in the axially front region (VB). Heat protection element (50) according to one of Claims 1 to 4, wherein a single circumferential connecting section (52) is formed in the axially front region (VB), in particular in the form of a circumferential welded or soldered seam. Heat protection element (50) according to one of the preceding claims, wherein the end section (64) is bent over axially forwards, in particular is bent over in the manner of a rim. Heat protection element (50) according to one of the preceding claims, wherein in the axially central region (MB) at least three radially inwardly shaped beads are distributed in the circumferential direction and serve as respective support sections (58, 62). Heat protection element (50) according to one of Claims 1 to 7, wherein a single circumferential support section (58) is provided in the axially central area (MB), which can be brought into contact with a ring seal arrangement (62), in particular a sealing cord, supported on the bearing chamber or stands. Heat protection unit (70) for a bearing chamber (60) of a gas turbine (10), in particular an aircraft gas turbine, consisting of a heat protection element (50) according to one of the preceding claims and a further protective element (54) of a seal carrier which is located in an axially front area (VB) of the Heat protection unit (70) is materially connected to the heat protection element (50). Gas turbine (10), in particular aircraft gas turbine, having at least one bearing chamber (60) around which a heat protection element (50) according to one of Claims 1 to 9 or a heat protection unit (70) according to Claim 10 is arranged. Gas turbine (10) according to claim 11, wherein the heat protection element (50) is provided in the region of a turbine center frame (34) or as part of a turbine center frame (34).

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