DE102020216488A1 - SEALING RING FOR A FLOW MACHINE - Google Patents

Abstract

The present invention relates to a sealing ring (10) for a turbomachine (1) which is interrupted in a circumferential direction (21) in relation to a ring axis (11) of the sealing ring (10), a first and a second section (20.1, 20.2) of the sealing ring (10) adjoin one another in an overlap area (30) and have an overlap (31), in particular a radial and/or axial overlap, the first section (20.1) in the overlap area (30) having a cross section that is at least Makes up 50% of its cross section outside the overlap area (30), and the second section (20.2) in the overlap area (30) also has a cross section that makes up at least 50% of its cross section outside the overlap area (30).

Description

technical field

The present invention relates to a sealing ring for a turbomachine.

State of the art

The turbomachine can, for example, be a jet engine, e.g. B. a turbofan engine. Functionally, the turbomachine is divided into compressor, combustion chamber and turbine. In the case of the jet engine, for example, the air drawn in is compressed by the compressor and burned in the downstream combustion chamber with added kerosene. The resulting hot gas, a mixture of combustion gas and air, flows through the downstream turbine and is expanded in the process. The turbine also extracts a proportion of the energy from the hot gas in order to drive the compressor.

In addition to the flow through the gas duct, there is a so-called secondary air system, which is used, for example, to provide cooling air, but can also take on more extensive tasks. Irrespective of the function in detail, this results in fluid paths radially inside and/or outside of the gas channel, in or on which the sealing ring described here can be used. It can be used both for the relative sealing of parts or components within a module and between the modules, see below in detail. This is intended to illustrate a preferred field of application, but initially not to limit the generality of the subject matter.

Presentation of the invention

The present invention is based on the technical problem of specifying a particularly advantageous sealing ring.

This is achieved according to the invention with the sealing ring according to claim 1. This is interrupted, what z. B. can be advantageous in terms of assembly and disassembly. Two sections of the sealing ring adjoin one another in an overlapping area that extends over a peripheral section. There the sections have an overlap, in particular an axial and/or radial overlap. Furthermore, they are designed in such a way that they each have a cross section in the overlap area, in particular in the overlap area a minimum cross section, which makes up at least 50% of their respective cross section, in particular their respective minimum cross section or average cross section, outside the overlap area.

A comparatively stable structure is created with a corresponding minimum cross-section, which both adjacent sections have in the overlapping area, namely relatively thin “knots” or “fingers” can be avoided. During operation of the turbomachine or the engine, for example, vibrations can be excited and relative movements can occur, which can result in material removal, ie wear of the sealing ring, over the period of operation. The sealing ring can, for example, be mounted in a groove and “wander” in the groove due to the relative movement and/or also be pressed axially against a wall delimiting the groove due to the flow pressure.

Irrespective of the wear mechanism in detail, the resulting material removal from thin structures (branches or fingers) could ultimately lead to the remaining cross-sectional areas becoming so thin that such a structure breaks off. This can result in a leak or, in the worst case, even further damage to the turbomachine or the engine (so-called domestic object damage, DOD). This is prevented with the minimum cross-section that both the first and the second section have in the overlapping area.

Preferred embodiments can be found in the dependent claims and the disclosure as a whole, with the presentation of the features not always making a detailed distinction between the sealing ring, a module arrangement with a sealing ring and the turbomachine/the engine, or corresponding methods or uses. In any case, the disclosure is to be read implicitly with regard to all categories of claims.

The information "axial", "radial" and "circumferential", as well as the associated directions (axial direction etc.), refer to the ring axis of the sealing ring. When the sealing ring is mounted in the module arrangement or turbomachine, this typically coincides with the longitudinal axis of the turbomachine or axis of rotation of the rotors. The radial directions are perpendicular to the ring or longitudinal or rotational axis, and the preferred "radial overlap" between the first and second sections is for a part of the radial directions, i.e. the first and second sections are arranged sequentially in the corresponding radial directions ( placed radially on top of each other). In general, the sealing ring can also be interrupted several times, ie it can be segmented; however, there is preferably only exactly one interruption, ie the first and second sections are one piecemeal with each other. The first and the second section can adjoin one another outside of the overlapping area, merge integrally into one another and/or have the same length.

The "cross-section" referred to in the skin claims can generally also be the cross-sectional area, for example, so that the first and/or second section in the overlapping area (each) has a cross-sectional area that is at least 50% of its cross-sectional area outside of the overlapping area matters. Alternatively, “cross-section” can also be read as the width taken at the respective cross-section (“cross-sectional width”), generally for example also as the radial cross-sectional width, but in a preferred embodiment as the axial cross-sectional width.

In detail, the axial cross-sectional width can be taken, for example, in a respective axial section, ie in a sectional plane containing the ring axis. In such a section, it then results as the maximum axial extent of the respective section, e.g. B. as a distance between an axially front and an axially rear end face of the section. The cross-sectional width criterion can preferably apply to all axial sections through the overlapping area. If the section in question is divided into several areas viewed in the axial section, each area should preferably have an axial minimum cross-sectional width according to the main claim. Viewed in axial section, however, the sections are preferably each contiguous, ie not subdivided. If the respective section outside the overlapping area has a variable axial cross-sectional width, a mean value formed over the corresponding section outside of the overlapping area is taken as the basis for the axial cross-sectional width. Preferably, however, the axial cross-sectional width of the first and/or second section is constant outside of the overlapping area.

The axial cross-sectional width of the first and/or second section in the overlapping area is at least 50% of its axial cross-sectional width outside of it, with further advantageous lower limits being increasingly preferred in the order in which they are named at least 60%, 70%, 80%, 90%, 95% or 100%. In other words, in a preferred embodiment, the axial cross-sectional width of the first section in the overlapping area can be at least as large as its axial cross-sectional width outside of it and/or the axial cross-sectional width of the second section in the overlapping area can be at least as large as its axial cross-sectional width outside of it. This allows a particularly wear-resistant overlap area to be designed, especially if both sections meet the criterion.

In a preferred embodiment, at least one of the two sections in the overlapping area is designed with an axial thickening, so the axial cross-sectional width of this section in the overlapping area is even greater than outside of it. As discussed in more detail below, positioning the seal ring such that the axial bulge faces upstream may be beneficial when downstream wear occurs due to flow pressure. Possible upper limits of the axial thickness of the respective section in the overlap area can be, for example, at most 300%, 250%, 200% or 150% of its axial thickness outside the overlap area, possible lower limits (independent of this) at least 110%, 120% or 130%

In a preferred embodiment, the sections in the overlapping area have an axial overlap in such a way that, in principle, there is a continuous sealing surface. Depending on the application and arrangement, the sealing surface can be formed by a lateral surface of the sealing ring facing radially inwards or radially outwards, and this sealing surface should be uninterrupted, neglecting axial separating surfaces that are perpendicular to the ring axis. The axial overlap means, for example, that the first and second sections are arranged axially one after the other in the overlap region, at least radially at the height of the lateral surface.

According to a preferred embodiment, the sealing ring has a local radial thickness across the segments, ie in the overlapping area and outside of it, which deviates by at most 20% from an average radial thickness. Further preferred upper limits of the deviation are, in the order in which they are mentioned, increasingly preferably at most 15%, 10% or 5%, and the radial thickness is preferably constant (0%). The local radial thickness is taken in each case along a respective radial direction, the mean radial thickness results as the mean value formed over the first and second sections. The sealing ring particularly preferably has a constant radial thickness all around.

In a preferred embodiment, the sections in the overlapping area form a closed end face, independent of a circumferential offset. The latter means that even if the two sections are not pushed together completely all around, but are slightly offset, for example due to thermal expansion, there is a closed end face. In other words, in the end face there are no undersides visible in an axial view over its entire radial height refraction, i.e. no circumferential distance between the sections.

According to a preferred embodiment, the sections in the overlapping area abut one another with a contact surface which, viewed in an axial section, is tilted at least over a section of its axial extent to the axial direction, i.e. encloses an angle greater than 0° with the axial direction. This particularly preferably applies to all axial sections through the contact surface or the overlapping area. Viewed in a respective axial section, the contact line can in general be tilted with respect to the axial direction, but can extend in a straight line. However, a contact line with a curved and/or angled course is preferred (the latter means that the contact line is composed of several sections which are straight but angled relative to one another).

In a preferred embodiment, the contact line runs along the axial direction with a maximum and/or a minimum. At a maximum, for example, the radial distance of the contact line to the ring axis can increase and then decrease, whereas at a minimum it decreases and then increases. A combination of minimum and maximum can result, for example, with a lying S-shape.

According to a preferred embodiment, the contact line has a V-shape, particularly preferably this V-shape is open radially inward, so it is figuratively speaking upside down. Such a sealing ring can then be arranged particularly advantageously in a radially outwardly open groove. Stability and wear advantages can then result, for example, if the section which, viewed in axial section, forms the convex part of the V-shape is arranged in the groove and the other section, which is concave in section due to the V-shape, outside of it . This is because the convex section can be more stable and thus less prone to wear with regard to material removal on the walls enclosing the groove.

The invention also relates to a module arrangement for a turbomachine, which has a sealing ring disclosed in the present case. This is arranged in the secondary air system, ie radially inside or outside of the gas duct. Reference is expressly made to the state-of-the-art assessment. The sealing ring can seal within a module or also between two modules, in particular between a turbine module and an intermediate housing. Such an intermediate housing can be arranged, for example, axially between a low-pressure and a high-pressure turbine module or, in other words, between turbine modules rotating at different speeds (on different shafts).

According to a preferred embodiment, the sealing ring is placed in the module arrangement in such a way that the axial thickening (see above) is upstream. In operation, the sealing ring is then pushed downstream by the flow pressure, which, as described above, can result in wear. The axial thickening, which ensures the integrity in the overlap area, then remains largely unaffected by this.

According to a preferred embodiment, the sealing ring is arranged in a groove, with a wall axially delimiting the groove being offset axially in the region of the axial thickening, in particular axially forward. Alternatively, this wall can also be interrupted in the overlap area, so that the axial thickening sits in the interruption.

In a preferred embodiment, the sealing ring is used in an intermediate housing (see above), in particular a turbine intermediate housing. It can be arranged radially inside or outside of the gas duct, the turbine center frame can in particular also be equipped with several sealing rings, e.g. at the upstream end with a sealing ring radially on the inside and/or a sealing ring radially on the outside, and alternatively or additionally on the downstream end with a sealing ring radially on the inside and/or a sealing ring radially on the outside.

character list

The invention is explained in more detail below using an exemplary embodiment, with the individual features within the framework of the independent claims also being able to be essential to the invention in a different combination and no distinction being made in detail between the different claim categories.

• 1 ein Strahltriebwerk in einem Axialschnitt;
• 2 einen erfindungsgemäßen Dichtring in einer schematischen Axialansicht;
• 3a zwei Abschnitte des Dichtrings gemäß 2 in einer Axialansicht;
• 3b die Abschnitte gemäß 3a in einer Radialansicht;
• 4 die Abschnitte gemäß 3a,b in einem Axialschnitt;
• 5a,b zwei Abschnitte eines alternativ ausgestalteten Dichtrings mit einer axialen Aufdickung in einer Radialansicht;
• 6 verschiedene Möglichkeiten zur Positionierung eines erfindungsgemäßen Dichtrings in schematischer Darstellung;
• 7 eine mögliche Anwendung in einer Detailansicht
• 8a,b,c einen Dichtrings gemäß einer weiteren erfindungsgemäßen Ausführungsform

In detail shows

• 1 a jet engine in an axial section;
• 2 a sealing ring according to the invention in a schematic axial view;
• 3a two sections of the sealing ring according to 2 in an axial view;
• 3b the sections according to 3a in a radial view;
• 4 the sections according to 3a,b in an axial section;
• 5a,b two sections of an alternatively designed sealing ring with an axial thickening in a radial view;
• 6 various options for positioning a sealing ring according to the invention in a schematic representation;
• 7 a possible application in a detail view
• 8a,b , c a sealing ring according to a further embodiment of the invention

Preferred embodiment of the invention

1 shows a turbomachine 1 in a schematic view, specifically a jet engine. The turbomachine 1 is functionally divided into a compressor 1a, a combustion chamber 1b and a turbine 1c. Both the compressor 1a and the turbine 1c are each made up of several stages, each stage is composed of a guide blade ring and a moving blade ring. During operation, the rotor blades rotate around the longitudinal axis 2.

2 shows a sealing ring 10 according to the invention in a schematic axial view, the ring axis 11 is perpendicular to the plane of the drawing (it coincides with the longitudinal axis 2 1 together). The sealing ring 10 is interrupted, in the area of the interruption 5 two sections 20 adjoin one another. A direction of rotation 21 is also identified.

3a shows in detail the first section 20.1 and the second section 20.2. The two sections 20.1, 20.2 have a radial overlap 31 in an overlapping area 30, so they are arranged there one after the other in a radial direction 35. The radial thickness is constant across sections 20.1, 20.2, i.e. a local radial thickness 33 corresponds to a mean radial thickness 34 formed over sections 20.1, 20.2.

For guidance and illustration shows 3b the two sections 20.1, 20.2 in a radial view, looking at it from radially outside, with the axial direction 22 also being referenced in addition to the overlapping region 30 and the circumferential direction 21.

4 shows the sections 20.1, 20.2 in an axial section, they adjoin one another along a contact line 40. This contact line 40 runs at an angle, in the present case it encloses a first angle α ₁ with an axial direction 22 in a first section 41.1 and a second angle α ₂ in a second axial section 41.2. In the present case, the contact line 40 forms a V-shape and the angles α ₁ , α ₂ are the same, just opposite.

In 4 a groove 45 is shown in dashed lines, in this case a groove open radially outwards. The V-shape of the contact line 40 is open radially inward, ie it is upside down. Accordingly, how off 4 As can be seen, the convex section (here 20.1) is arranged in the groove 45. In operation, flow pressure 46 may push the seal ring 10 downstream, which in the present orientation may result in wear on the seal ring 10 radially inward and axially rearward. The convex and therefore more stable section is placed in the groove 45 due to the orientation of the V-shape shown.

As per the cut 4 in synopsis with 3 As can be seen, the first section 20.1 in the overlapping area 30 has an axial cross-sectional width 48.1, which in the present example is just as large as its axial cross-sectional width 49.1 outside of the overlapping area 30. Furthermore, the second section 20.2 in the overlapping area 30 also has an axial cross-sectional width 48.2, which in the present example the same size as its axial cross-sectional width 49.2 outside of the overlap area 30. This avoids thin structures such as branches and fingers, etc., so that there is no risk of breakage in the overlapping area 30 in the event of wear and the resulting reduced cross sections.

5a shows an embodiment with an additional axial thickening 50 in the overlap area 30. In this example, a thickened section 51 is attached axially at the front of the first section 20.1, which extends radially over the entire height of the sealing ring 10. 5 shows a radial view from the outside, ie a lateral surface 55 of the sealing ring 10, which forms a continuous sealing surface 56 as outlined in dashed lines (ignoring axial separating surfaces 54). The wall 57 delimiting the groove 45 is provided with an interruption 53 in the region of the thickening 50 (the axial rear wall 58 runs continuously). 5b shows the same arrangement, with sections 20.1, 20.2 being slightly offset, ie sealing ring 10 is slightly open (cold state).

6 shows a module arrangement 59, thus schematically illustrating various possible uses of a sealing ring 10 according to the invention in the secondary air system 60, radially inside or outside the gas duct 61. The sealing ring 10 can be used in particular between a turbine center frame 65 and the upstream or downstream turbine module. A fairing 66 and a support strut 67 passing through it are shown schematically.

7 shows one of the possible uses according to 6 in a detailed view, namely a sealing ring arranged radially outside of the gas channel 61 at the downstream end of the fairing 66 10. The sealing ring 10 thus sits in principle between the intermediate turbine housing 65 and the downstream turbine module 70 (eg low-pressure turbine module). Of the latter, a rotor blade 71 can be seen, which is equipped with sealing tips 72 radially on the outside. These seal against a run-in covering 73, which can be designed as a honeycomb covering, for example. As can be seen from the illustration, the sealing ring 10 arranged in the groove 45 of the fairing 66 creates a seal for the downstream turbine module 70, for which purpose the run-in coating 73 is pulled a little far axially forward in the present example.

8th shows a sealing ring according to a further embodiment of the invention, in which features of the embodiments of 4 and 5 - to the description of which reference is made accordingly - are combined, in a radial top view ( 8a) , in perspective view ( 8b) and in cross section ( 8c ) in the overlap area 30.

Reference List

1

flow machine

1a

compressor

1b

combustion chamber

1c

turbine

2

longitudinal axis

10

sealing ring

11

ring axis

20

sections

20.1

first section

20.2

second part

21

direction of circulation

22

axial direction

30

overlap area

31

overlap

33

Local radial thickness

34

Mean radial thickness

36

radial direction

40

contact line

41.1

first section

α1

first angle

41.2

second part

α2

second angle

45

groove

46

inlet pressure

48.1

Axial cross-sectional width (overlap area 1st section)

48.2

Axial cross-sectional width (overlap area 2nd section)

49.1

Axial cross-sectional width (outside overlap area 1st section)

49.2

Axial cross-sectional width (outside overlap area 2nd section)

50

thickening

51

thickening section

53

interruption

54

axial interface

55

lateral surface

56

sealing surface

57

wall (axial front)

58

wall (axial rear)

59

module arrangement

60

secondary air system

61

gas channel

65

turbine center frame

66

fairing

67

support brace

70

turbine module

71

blade

72

sealing tips

73

running-in coating

Claims (15)

Sealing ring (10) for a turbomachine (1), which, in relation to a ring axis (11) of the sealing ring (10), is interrupted in a circumferential direction (21), wherein a first and a second section (20.1, 20.2) of the sealing ring (10) adjoin one another in an overlapping area (30) and have an overlap (31), in particular a radial and/or axial overlap, wherein the first section (20.1) in the overlapping area (30) has a cross section that makes up at least 50% of its cross section outside of the overlapping area (30), and the second section (20.2) also has a cross-section in the overlap area (30) which accounts for at least 50% of its cross-section outside the overlap area (30). sealing ring (10) after claim 1 , In which an axial cross-sectional width (48.1) of the first Section (20.1) in the overlapping area (30) at least 50% of its axial cross-sectional width (49.1) outside of the overlapping area (30). sealing ring (10) after claim 1 or 2 , in which the axial cross-sectional width (48.2) of the second section (20.2) in the overlapping area (30) is at least 50% of its axial cross-sectional width (49.2) outside of the overlapping area (30). Sealing ring (10) according to one of the preceding claims, in which the first and/or the second section (20.1, 20.2) is designed with an axial thickening (50) in the overlapping region (30), its axial cross-sectional width (48.1, 48.2) there ie larger than its axial cross-sectional width (49.1, 49.2) outside of the overlapping area (30). Sealing ring (10) according to one of the preceding claims, in which the first and the second section (20.1, 20.2) in at least one section of the overlap region (30) have an axial overlap such that a sealing surface (56) which extends from a radially inside or outside facing lateral surface (55) of the sealing ring (10) is formed, neglecting axial separating surfaces (54) is continuously formed without interruption. Sealing ring (10) according to one of the preceding claims, which has a local radial thickness (33) across the first and the second section (20.1, 20.2), i.e. in the overlapping area (30) and outside of the overlapping area (30), which deviates by at most 20% from an average radial thickness (34) formed as an average over the first and the second section (20.1, 20.2). Sealing ring (10) according to one of the preceding claims, in which the first and the second section (20.1, 20.2) form a closed end face in the overlapping region (30) viewed in the axial direction (22), even with an offset, in particular any offset offset, in the direction of rotation (21). Sealing ring (10) according to one of the preceding claims, in which the first and the second section (20.1, 20.2) in the overlapping region (30), viewed in an axial section, abut one another with a contact line (40) which at least in sections forms an angle > 0° with the axial direction (22). sealing ring (10) after claim 8 , in which the contact line (40) along the axial direction (22) has a course with a maximum and/or a minimum. sealing ring (10) after claim 9 , in which the contact line (40) has a V-shape. sealing ring (10) after claim 10 , in which the V-shape is open radially inwards. Module arrangement (59) for a turbomachine (1), with a sealing ring (10) according to one of the preceding claims, wherein the sealing ring (10) in the secondary air system (60) of the turbomachine (1) radially inside or outside of its gas duct (61) is arranged. Module arrangement (59) after claim 12 with a sealing ring (10). claim 4 , optionally also in connection with one of the Claims 5 until 11 , wherein the sealing ring (10) is arranged in the module arrangement (59) such that the axial thickening (50) is based on a flow through the gas channel (61) on the upstream end face of the sealing ring (10). Module arrangement (59) after claim 12 or 13 with a sealing ring (10). claim 4 , optionally also in connection with one of the Claims 5 until 11 , in which the sealing ring (10) is arranged in a groove (45) open radially inwards or radially outwards, a wall (57) axially delimiting the groove (45) being interrupted or axially offset in the region of the thickened portion (50). . Module arrangement (59) according to one of Claims 12 until 14 In which the sealing ring (10) seals between a turbine center housing (65) and a turbine module, in particular in a groove (45) of the turbine center housing (65) is arranged.

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