EP2818724B1 - Fluid flow engine and method - Google Patents

Description

The invention relates to a turbomachine with at least one circulation structure according to the preamble of patent claim 1, as well as a method for introducing a circulation structure into a housing of a turbomachine.

The pamphlets JP 63 183204 and EP 2 434 165 A1 disclose a circulation structure for a turbomachine, with a structural housing that is divided in a parting plane into a front structural area and a rear structural area.

Circulation structures or recirculation structures for fluid flow machines such as gas turbines and in particular their compressors are known as so-called "casing treatments" and "hub treatments". The primary task of the circulation structures is to increase an aerodynamically stable operating range of the compressor by optimizing the surge limit. An optimized surge limit distance enables higher compressor pressures and thus a higher compressor load. The disturbances responsible for a local flow stall and ultimately for the pumping of the compressor occur at the housing-side ends of the rotor blades of one or more compressor stages or at the hub-side, radially inner ends of the guide vanes, since the aerodynamic load in the compressor is highest in these areas . The flow in the area of the blade ends is stabilized by the circulation structures.

A fluid machine with such a circulation structure is in the DE102008010283A1 shown. The circulation structure is arranged in the compressor of the turbomachine, in particular a gas turbine, and has an annular space which is oriented coaxially to the axis of rotation of a rotor of the turbomachine and is open to the main flow path. Seen in the main flow direction of the main flow path, a plurality of chambers through which a flow can flow in the axial direction are positioned upstream of the annular space. A turbo machine with an alternative circulation structure is in the EP1478828B1 shown.

This circulation structure also has an annular space which is oriented coaxially to the axis of rotation of a rotor of the turbomachine and is open to the main flow path, in which, however, a multiplicity of flow guide elements are arranged.

The object of the invention is to create a turbomachine with at least one circulation structure which enables the circulation structure to be easily introduced into a housing of the turbomachine. Another object of the invention is to create a circulation structure that can be easily introduced into a housing of a turbomachine. Another object of the invention is to create a method for simply introducing a circulation structure into a housing of a turbomachine.

This object is achieved by a turbomachine with at least one circulation structure with the features of claim 1 and by a method with the features of claim 7.

A circulation structure according to the invention of the claimed turbomachine has a two-part structural housing which is divided in a radial parting plane into a front structural area and a rear structural area. The at least two-part design of the circulation structure simplifies its manufacture and, in particular, its integration into a turbo-machine housing.

The effect of the circulation structure can be improved if it has flow guide elements in the front structural area. The flow guide elements can have different lateral spacings from one another, different geometries and / or different positions to one another. The flow guide elements can thus have variable circumferential positions and geometries or courses, whereby the circulation structure can be set specifically to the respective application.

The turbomachine has at least one circulation structure which has an annular space with flow guide elements which surrounds a main flow path and is open to it. According to the invention, a two-part housing of the turbomachine for receiving the circulation structure is divided in a radial parting plane into a front housing area and a rear housing area.

The division of the turbomachine housing to accommodate the circulation structure in at least two housing areas in combination with the division of the circulation structure into at least two structure areas simplifies the production and introduction of the circulation structure. The front structural area and the rear structural area can be formed by individual insert or insert elements, cladding segments or liners and the like, which are separated in the circumferential direction and can be assembled to form a ring, or by ring segments closed in the circumferential direction. The axial division of the turbomachine housing and the circulation structure also enables the front structural area of the circulation structure, for example, to be brought directly into the front housing area of the turbomachine, since alternative milling paths and tools can be used through the lateral access provided by the axial division. In this way, the circulation structure can also be enlarged or made more compact. The terms "front" and "rear" each relate in the flow direction of a main flow through which the main flow path flows.

The introduction of the circulation structure can also be simplified if the same radial parting plane of the housing in the assembled state is the same as the radial parting plane of the circulation structure. In order to avoid jamming of the circulation structure during assembly, the rear structural area can be set back somewhat in relation to the parting planes in the assembled state, so that a minimal annular gap is formed between the structural areas in the assembled state.

In one embodiment, the flow guide elements are formed in the front structural area which is inserted into the front housing area. In this exemplary embodiment, the front structural area is composed of a multiplicity of insert or slide-in segments which are divided from one another in the circumferential direction and which are manufactured separately from the front housing area. Alternatively, the front structural area is a single circumferentially closed ring element which is manufactured separately from the front housing area. The separate manufacture of the front housing area and the front structural area enables the manufacture of the flow guide elements to be simplified.

In an alternative embodiment, the flow guide elements are introduced directly into the front housing area. As a result, separate insert or slide-in segments or a separate ring element for forming the front structural area are dispensed with, which means that fewer parts have to be assembled. In addition, the integral design of the front structural area in the front housing area reduces the weight of the turbomachine or its housing.

The rear structural area is preferably an integral front body section of a cladding element inserted into the rear housing area. The cladding element can consist of a multiplicity of individual cladding segments divided in the circumferential direction, which together form a closed ring, or it can be a single cladding ring. The body section can be a holding section of the cladding element for fastening the cladding element on or in the rear housing area, so that no additional sections have to be attached to the cladding element or its segments. The production of the flow guide elements can be simplified by the separate production of the rear housing area and the rear structural area. Preferably, the cladding element carries a rubbing or running-in coating extending over the cladding element in the circumferential direction and forming a closed ring, so that a blade tip side flow around a row of blades opposite the cladding element is prevented.

In a method according to the invention for introducing a circulation structure into a housing of a turbomachine, a housing of the turbomachine is provided which is divided in a radial parting plane into a front housing area and a rear housing area. A front structural area of the circulation structure is then introduced into the front housing area and a rear structural area of the circulation structure is introduced into the rear housing area. Then the housing areas are joined in the parting line.

Due to the axial separation of the flow machine housing in the area of the circulation structure and the radial separation of the circulation structure, the method enables a simple one Introducing and especially an optimal alignment of the circulation structure. Introducing in this case means both the insertion of structural areas of the circulation structure produced separately from the turbo-engine housing and an integral formation of the structural areas in the turbo-engine housing, for example by means of a milling process.

Preferably, in the front structural area, air ducts are worked out between flow guide elements in a single processing step. This measure shortens the production time of the circulation structure compared to known production times. An exemplary tool is an end mill. The tool agitation is preferably selected in such a way that flow properties of the flow guide elements remain unaffected or almost unaffected by this.

The rear structural area can be turned out, for example. The rear structural area is formed integrally or directly in the rear housing section, as a result of which fewer parts have to be assembled. If, in addition, the front structural area is worked out directly in the front housing area, for example by means of milling processes, only the housing areas need to be assembled.

To set, for example, different or reduced transition radii of the flow guide elements from the base of the air ducts, these can be processed separately after the air ducts have been milled. This can be done, for example, by means of an alternative end mill with a milling radius that is reduced compared to the end mill used to form the air ducts.

Other advantageous exemplary embodiments of the invention are the subject of further dependent claims.

Figur 1

einen Längsschnitt durch eine Strömungsmaschine im Bereich einer Zirkulationsstruktur,

Figur 2

eine Werkzeugführung zur Ausbildung einer alternativen Zirkulationsstruktur,

Figuren 3, 4 und 5

verschiedene Ausbildungen von Strömungsleitelementen im vorderen Strukturbereich der Zirkulationsstruktur,

Figuren 6 und 7

beispielhafte Werkzeugführungen zur Ausbildung der Strömungsleitelemente mit kleinen Übergangsradien, und

Figuren 8 und 9

Werkzeugführungen bei einem einteiligen Strömungsmaschinengehäuse im Bereich der Zirkulationsstruktur.

In the following, preferred exemplary embodiments of the invention are explained in more detail with the aid of schematic representations. Show it:

Figure 1

a longitudinal section through a turbomachine in the area of a circulation structure,

Figure 2

a tool guide to create an alternative circulation structure,

Figures 3, 4 and 5

various designs of flow guide elements in the front structural area of the circulation structure,

Figures 6 and 7

exemplary tool guides for forming the flow guide elements with small transition radii, and

Figures 8 and 9

Tool guides in a one-piece flow machine housing in the area of the circulation structure.

In Figure 1 a longitudinal section through a main flow path or flow channel 1 of a turbomachine in the area of its stator housing 2 is shown. In particular, in Figure 1 a section through a circulation structure 4 introduced into the stator housing 2 is shown.

The flow channel 1 is carried by a main flow as shown in FIG Figure 1 flows through from left to right. The turbomachine is, for example, a gas turbine and in particular an aircraft engine. The stator housing 2 forms a part of the housing of the turbomachine and is preferably a compressor of the turbomachine.

In the in Figure 1 A guide vane ring 6, which is adjustably mounted in the stator housing 2, and a rotor blade row 8 assigned to a rotor are arranged in the flow channel 1. In relation to the main flow direction, the guide vane ring 6 is arranged in front of the rotor blade row 8 or the rotor blade row 8 behind the guide vane ring 6.

In order to accommodate the circulation structure 4, the stator housing 2 is divided into a front housing area 10 and a rear housing area 12 in a radial parting plane Ts. The housing areas 10, 12 each have one to the flow channel 1 and one to the radial one Parting plane Ts open front annular recess 14 and rear annular recess 16 are provided. The annular expansions 14, 16 are arranged opposite one another in the axial direction or flow direction and together form an approximately U-shaped annular recess.

The circulation structure 4 is divided into a front structural area 18 and a rear structural area 20 in a radial parting plane Tz. The radial parting plane Tz is positioned such that it lies on the radial parting plane Ts of the stator housing 2 in the assembled state shown. In the assembled state, the parting planes Ts, Tz are thus identical or congruent. In order to avoid jamming of the circulation structure 4 during assembly and to avoid thermal expansion compensation between the circulation structure 4 and the housing 2, the rear structure area 20 is set back somewhat in the assembled state with respect to the parting planes Ts, Tz, so that as in FIG Figure 1 shown, in the assembled state a minimal annular gap 21 is formed between the structural areas. Of course, the rear structural area 20 can also be guided as far as the parting planes Ts, Tz and the front structural area 18 can be set back with respect to the parting planes Ts, Tz in order to form the annular gap 21.

The circulation structure 4 defines an annular space 22 which surrounds the flow channel 1 in the radial direction and is open to it. The circulation structure 4 is preferably oriented coaxially to the axis of rotation of the rotor.

In the exemplary embodiment shown, the front structural region 18 is designed as an insert element 24 inserted into the front annular recess 14, in which a plurality of flow guide elements 26 spaced from one another in the circumferential direction are positioned. In the exemplary embodiment shown, the insert element 24 is a ring segment that is closed in the circumferential direction. However, it can also consist of a multiplicity of segments which are separated from one another in the circumferential direction and which form a closed ring in the assembled state. The flow guide elements 26 have a blade-like profile and are in the circumferential direction via individual air ducts 28 extending approximately in the axial direction (see FIG. Figures 3 to 7 ) spaced from each other.

The rear structural region 20 is configured with circumferential symmetry and, in the exemplary embodiment shown, has a circumferential groove facing upstream of the flow guide elements 26. The structural area 20 is integrated in a cladding element 30 which, in the exemplary embodiment shown, is composed of a plurality of cladding segments that are separated from one another in the circumferential direction and, in the assembled state, form a closed ring. Alternatively, the cladding element 30 is a single ring element closed in the circumferential direction. In order to prevent flow around the rotor blade row 8 on the blade tip side, the cladding element 30 is provided with a circumferential abradable coating 32 on its side facing the rotor blade row 8.

In particular, the rear structural region 20 is formed by an integral front body section 34 of the cladding element 30, which is inserted into the stator-side rear annular extension 16. In particular, the body section 34 is a holding section for fastening the cladding element 30 to or in the rear housing area 12. The body section or holding section 34 has a downstream holding ring 36, which is used for fastening the cladding element 30 in an upstream and in the rear housing area 12 introduced annular retaining groove 38 engages positively.

In Figure 2 a tool guide for forming a circulation structure 4 is shown, which is introduced integrally into a two-part stator housing 2. The stator housing 2 is as described in FIG Figure 1 divided in two into a front housing area 10 and a rear housing area 12. A front structural area 18 of the circulation structure 4 is arranged in the front housing area 10 and a rear structural area 20 of the circulation structure 4 is arranged in the rear housing area 12.

As in Figure 2 As shown, the flow guide elements 26 are introduced into the front housing area 10 by means of a milling tool 40, for example an end mill. The tool guidance is such that air channels 28 formed between the flow guide elements 26 (see Fig. Figures 3 to 5 ) can be produced in a single processing step. Accordingly, the end mill 40 has a milling width which corresponds to a circumferential spacing of the flow guide elements 26 from one another.

In this exemplary embodiment, the rear, circumferentially symmetrical structural area 20 is also formed by means of the end mill 40 in the stator housing 2, and in particular in the rear housing area 12. Alternatively, the rear structural area 20 in the rear housing area 12 can be pre-turned or only rotated prior to milling with the end mill 40. Figure 9 ).

As in Figure 3 As shown, the flow guide elements 26 or the air ducts 28 formed between the flow guide elements 26 can have a uniform circumferential positioning. In particular, the air channels 28 then have a uniform concave basic contour 42, a uniform angle of incidence a in the circumferential direction, a uniform radial height h and a uniform circumferential width b _L. With uniform circumferential positioning, the flow guide elements 26 have a constant circumferential width b _S. The width bs corresponds to the width of the end mill 40.

As in Figure 4 However, as shown, the flow guide elements 26 can also have a varying width b _S1 , b _S2 , whereas the air guide channels have a uniform width b _L , so that both the flow guide elements 26 and the air channels 28 have a variable circumferential positioning.

As shown in Figure 5 In addition, the angles of attack α ₁ , α _{2 of} the air ducts 28 and / or the radial height h ₁ , h _{2 of} the air ducts 28 can vary.

In all prescribed embodiments according to Figures 2 to 5 is the same that, in order to introduce the circulation structure 4 into the stator housing 2, the stator housing 2 is first divided in a radial separation plane Ts into a front housing area 10 and a rear housing area 12. Then the front structural area 18 of the circulation structure 4 is introduced into the front housing area 10 and the rear structural area 20 of the circulation structure 4 is introduced into the rear housing area 12. The front housing area 10 and the rear housing area 12 are then joined. The formation of the air channels 28 and thus that of the flow guide elements 26 is preferably carried out in a single processing step.

In the Figures 6 and 7 the formation of flow guide elements 26 is shown, the transition radius _{r r of} which has been reworked to the basic contour 42 of the air guide channels 28. In the embodiments according to Figures 6 and 7 the transition radii _r r are reduced compared to the original transition radius r _u .

The reduced transition radii r _r are preferably formed by means of alternative end mills 44 which, compared to the original end mill 40, have a reduced milling radius and a reduced milling width. As in Figure 6 As shown, the reduced milling cutter 44 can be in overlapping paths or, as in FIG Figure 7 shown, be guided in adjacent tracks. In addition, as in Figure 6 shown, the reduced milling cutter 44 are driven into different depths between the flow guide elements 26, so that in addition to a reduction in the transition radii _{r r} , the basic contour 42 itself is also changed. As in Figure 6 As shown by way of example, a quasi-flat basic contour 42 can thus be created, which extends almost tangentially to the circumferential direction. As in Figure 7 As shown by way of example, a quasi-flat basic contour 42 can thus also be created, which extends obliquely to the circumferential direction.

In Figure 8 a tool guide for introducing a circulation structure 4 into a one-piece stator housing 2 of a turbomachine is shown. The circulation structure 4 has a front asymmetrical structural area 18 with a multiplicity of flow guide elements 26 and a rear, circumferentially symmetrical structural area 20. The circulation structure 4 is introduced directly into the stator housing 2 by means of mechanical processing. Preferably, the air ducts 28 between the flow guide elements 26, as in FIGS Figures 2 to 5 described, worked out in a single processing step. In addition, the rear structural area 20 can be machined out of the stator housing 2 using a corresponding milling guide.

As shown in Figure 9 the rear structural area 20 can be pre-machined in a turning operation as indicated by the gap 46. Of course, the rear structural area 20 can also be rotated completely.

Disclosed is a turbomachine with at least one circulation structure, which has an annular space with flow guide elements, which surrounds a main flow path and is open to the latter, a housing of the turbomachine being divided into a front housing area and a rear housing area for receiving the circulation structure in a radial dividing plane, and that the circulation structure is divided in a radial parting plane into a front structure area and a rear structure area, a circulation structure divided into two in the axial direction and a method.

List of reference symbols

1

Flow channel / main flow path

2

Stator housing / housing

4th

Circulation structure

6th

Guide vane ring

8th

Blade row

10

front housing area

12

rear housing area

14th

front ring recess

16

rear ring recess

18th

front structural area

20th

rear structural area

21st

Annular gap

22nd

Annulus

24

Insert element

26th

Flow guide element

28

Air duct

30th

Cladding element

32

Abrasive coating

34

Body section / holding section

36

Retaining ring

38

Holding groove

40

Milling tool

42

Basic contour

44

Milling cutter

46

gap

Ts

radial parting plane stator housing

Item

radial parting plane circulation structure

α, α ₁ , α ₂

Angle of attack

h, h ₁ , h ₂

height

b _L

Wide air duct

b _S , b _S1 , b _S2

Wide flow guide element

r _u

original transition radius

r _r

reduced transition radius

Claims (10)

1. Turbomachine comprising at least one circulation structure (4), the circulation structure (4) having an annular space (22) which has flow guide elements (26) and surrounds and is open to a main current path (1), a two-part housing (2) of the turbomachine for receiving the circulation structure (4) being divided in a radial plane of separation (Ts) into a front housing region (10) and a rear housing region (12), characterized in that the circulation structure has a two-part structure housing which is divided in a radial plane of separation (Tz) into a front structure region (18) and a rear structure region (20).
2. Turbomachine according to claim 1, wherein flow guide elements (26) in the front structure region (18) have different lateral spacings from one another and/or positions with respect to one another.
3. Turbomachine according to either claim 1 or claim 2, wherein, in the assembled state, the radial plane of separation (Ts) of the housing (2) is the same as the radial plane of separation (Tz) of the circulation structure (4).
4. Turbomachine according to any of claims 1 to 3, wherein the flow guide elements (26) are formed in the front structure region (18) and said front structure region is inserted into the front housing region (10).
5. Turbomachine according to any of claims 1 to 4, wherein the flow guide elements (26) are introduced directly into the front housing region (10).
6. Turbomachine according to any of the preceding claims 1 to 5, wherein the rear structure region (20) is an integral front body portion (34) of a lining element (30) which is inserted into the rear housing region (12).
7. Method for introducing a circulation structure (4) into a housing (2) of a turbomachine, comprising the steps of:
   providing a two-part housing (2) of the turbomachine, which housing is divided in a radial plane of separation (Ts) into a front housing region (10) and a rear housing region (12), introducing a front structure region (18) into the front housing region (10), and introducing a rear structure region (20) into the rear housing region (12), and joining the housing regions (10, 12) in the plane of separation (Ts).
8. Method according to claim 7, wherein, in the front structure region (18), air ducts (28) are formed between flow guide elements (26) in a single machining operation in each case.
9. Method according to either claim 7 or claim 8, wherein the rear structure region (20) is milled.
10. Method according to any of claims 7 to 9, wherein transitional radii (ru, rr) are machined after the flow guide elements (26) are formed.

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