WO2022171240A1

WO2022171240A1 - Method for producing a flow structure for a turbomachine

Info

Publication number: WO2022171240A1
Application number: PCT/DE2022/100084
Authority: WO
Inventors: Karl-Hermann Richter; Gerhard WESTENRIEDER
Original assignee: MTU Aero Engines AG
Priority date: 2021-02-12
Filing date: 2022-01-31
Publication date: 2022-08-18
Also published as: DE102021201367A1

Abstract

The present invention relates to a method for producing a flow structure (20) for a turbomachine (1), in which method a blade (22) is joined at a first end (31) to a main body (21), which blade (22) has, in a portion (34) distal from the first end (31), over at least one segment (37) in relation to a circumference about its longitudinal axis (33), a hollow-cylindrical shape having a wall thickness dhohl, wherein the blade (22), during the joining, is designed either as a solid body (55) or has a wall thickness d1 > dhohl in a first portion (32) at the first end (31), wherein the blade (22) is gripped in the first portion (32) during joining to the main body (21).

Description

METHOD OF MAKING A FLOW STRUCTURE FOR A FLUID MACHINE

DESCRIPTION

technical field

The present invention relates to a method for producing a flow structure with a base body and a blade.

State of the art

The turbomachine can, for example, be a jet engine, e.g. B. to a mantle power 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 extracts energy from the hot gas in order to drive the compressor and, in the case of turbofan engines, the fan. 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. Depending on the function in detail, this results in fluid paths radially inside and/or outside of the gas channel, with the present flow structure being able to be used in particular in this secondary air system. This is intended to illustrate a particularly advantageous area of use, but not initially to restrict the subject in its generality.

Presentation of the invention

The present invention is based on the technical problem of specifying an advantageous method for producing a flow structure for a turbomachine. According to the invention, this is achieved with the method according to claim 1 . In this case, the airfoil is attached to the base body by joining, with it being gripped, that is to say held, in a first section during joining. This first section is at that end of the airfoil at which the joint connection is made (“first end”), i.e. the end facing the base body. In a section distal to the first end (facing away from the base body), the blade has a hollow-cylindrical shape (hollow profile) with a wall thickness dhohi, based on one revolution around its longitudinal axis, which is motivated, for example, by the application, i.e. flow technology. It can be a closed hollow profile or a hollow profile that is open in the direction of rotation. On the other hand, at the first end in the first section, the airfoil is designed either as a solid body or, in the case of a hollow-cylindrical configuration, at least with a wall thickness di that is greater than dhohi.

With this configuration, for example, the mechanical stability of the airfoil can be increased at the first end, ie it can be held reliably during joining. The blade can be z. B. clamp well in a holding tool. In addition, compared to an airfoil, for example, which is hollow-cylindrical with the wall thickness dhohi over its entire length, an interaction surface can be larger when joining to the base body. In the case of a preferred welded connection, for example, the connection or welding surface can be larger and the necessary friction or compression forces can thus be increased, for example depending on the welding process.

Preferred embodiments can be found throughout the disclosure and in particular in the dependent claims, with the presentation of the features not always making a distinction in detail between method and device or application aspects; at least implicitly, the disclosure is always to be read with regard to all categories of claims.

In general, joining the blade and base body together can be advantageous compared to production from a solid piece, for example in that the volume to be removed would be many times larger than the volume of the finished component with the latter due to the thin-walled structure of the blade. This would mean long processing times and high tool wear, especially since the materials in question are usually comparatively hard (see below for details). Therefore, according to the invention, it is joined and the blade is then geometrically optimized. The wall thickness di can, for example, be at least 2, 4, 6, 8 or 10 times the wall thickness dhohi (with theoretical upper limits at e.g. 500, 300 or 100 times ).

The “hollow-cylindrical shape” of the airfoil is preferably the shape of a hollow cylinder with a circular cross-section (in general, however, a deviation from the circular shape is also conceivable, for example an elliptical cross-section). The hollow-cylindrical shape is present at least in a “segment”, that is to say in relation to a longitudinal axis of the airfoil at least in a section of the revolution around this longitudinal axis. In the other segment, the airfoil is then at least open in the finished flow structure, so there is no airfoil material there. The airfoil can this open, z. B. have a semi-cylindrical shape in the distal section during the joining process, but it can also be joined to the base body as a closed hollow cylinder and then opened ßend.

In the finished structure, the airfoil can preferably have the same outside diameter in the first and the distal section, and this can particularly preferably already be the case during the joining. In general it has to

Airfoil in a section under consideration does not necessarily have a constant wall thickness, but this can also assume different values within a section. The wall thickness considerations and comparisons are then based on an average value of the wall thickness formed over the corresponding section, i.e. dhohi or di (or also d2, see below) is formed by averaging. However, the wall thickness in a respective section is preferably constant.

The base body preferably has a ring shape, the ring axis of which then particularly preferably coincides with the longitudinal or rotational axis of the turbomachine and is angled, in particular perpendicular to the longitudinal axis of the blade leaf. In relation to the ring axis, a plurality of blades can be joined to the base body distributed circumferentially, see below in detail. The blade(s) preferably extends radially outward away from the base body in relation to the ring axis. In other words, the airfoil or the airfoils are/are preferably arranged on an outer lateral surface of the ring.

Irrespective of these details, in a preferred embodiment the blade is machined to remove material after it has been joined to the base body. In general, this can also be done electrochemically, for example; mechanical material processing, in particular metal-cutting material processing, for example by drilling or milling, is preferred.

In the case of the airfoil, which is designed as a solid body (solid cylinder) during the joining in the first section, a hollow-cylindrical shape can be created with the material-removing machining. In the case of the airfoil that is already hollow-cylindrical in the first section during the joining process, an inner diameter in the first section can be expanded with the machining. With the material-removing machining, a channel is preferably created or widened between the at least segmentally hollow-cylindrical shape of the blade blade in the distal section and a space radially inside the annular base body. According to a preferred embodiment, after the material-removing machining, the airfoil has a wall thickness d2 in the first section, which is essentially equal to the wall thickness dhohi. The wall thicknesses can therefore deviate from one another by, for example, less than 10%, 5% or 3%, with exactly the same wall thicknesses also being possible within the scope of the usual technical accuracy (deviation of 0%). In an alternative preferred variant, however, a greater wall thickness can remain in the first section of the finished structure (> dhohi), ie the geometry optimized for joining can also still be visible in the finished structure. In a preferred embodiment, the wall thickness dhohi in the distal section is at most 5 mm, in the order in which they are mentioned it is increasingly preferred at most 4 mm, 3 mm or 2 mm. Possible lower limits can be 0.5 mm or

0.75 mm are particularly preferred z. B. be a wall thickness of about 1 mm. Regardless of these details, the wall thickness dhohi preferably remains unchanged in the distal section, ie the wall thickness during joining corresponds to that of the finished structure.

According to a preferred embodiment, the first section has a length of at least 5 mm, with at least 8 mm or at least 10 mm being further and particularly preferred. Advantageous upper limits, which should also be disclosed independently of the provision of a lower limit, can be, for example, in the order in which they are named, at most 25 mm, 20 mm or 15 mm, which is increasingly preferred. A lower limit can, for example, ensure that the first section can be gripped or clamped reliably; an upper limit can e.g. B. help to limit the post-processing effort.

According to a preferred embodiment, the base body and/or the blade is/are made of a nickel material, preferably both. Such a nickel material, e.g. IN718, Udimet 720 or ME16, can be comparatively hard, so that the advantages mentioned at the beginning compared to production from solid material can particularly come into play.

In a preferred embodiment, the blade is joined to the base body by friction welding, ie by a relative movement under pressure. The friction welding can be, in particular, a rotary friction welding with a rotating movement of the blade or an orbital friction welding with a circular oscillating movement. Irrespective of how the method is carried out in detail, the airfoil can be reliably clamped due to the configuration according to the main claim for the application of movement and pressure that is necessary here.

According to a preferred embodiment, the flow structure is heat-treated after joining, for example at a temperature of at least 500° C., 600° C. 700°C or 800°C. Possible upper limits can be 1200 °C or 1000 °C, for example. Post-processing can also be preferred to the effect that a bead, in particular a friction-weld bead, is removed, in particular at the transition from an outer wall surface of the airfoil to the base body. The joining bead is particularly preferably removed first and the structure is then heat-treated.

In a preferred configuration, the finished structure has a total of at least four blades, preferably at least six blades. Partial upper limits can be, for example, in the order in which they are named, at most 20, 16, 14, 12 or 10 blade blades, which is increasingly preferred.

As already mentioned, the invention also relates to a flow structure which has a base body and an airfoil attached thereto. In the finished structure, the airfoil is designed at the first end either as a solid body or with a wall thickness di greater than dhohi (di > dhohi). After the joining, it is possibly not machined at all or at least not in such a way that material is removed at the first end such that the diameter there becomes equal to dhohi. In other words, an increased wall thickness remains at the first end.

The invention also relates to the use of such a flow structure in a turbomachine, preferably an aircraft engine, in particular in its secondary air system. The flow structure can thus be arranged radially inside or outside of the gas duct through which the compressor or combustion gas flows during operation, in which the guide vanes and rotor blades are placed.

Brief description of the drawings

The invention is explained in more detail below using an exemplary embodiment, with the individual features within the scope of the independent claims also being able to be essential to the invention in a different combination and still not in the

A distinction is made between the different claim categories.

In detail shows FIG. 1 shows a turbomachine, namely a ducted power unit, in a schematic section;

FIG. 2 shows a flow structure with a base body and several blades;

FIG. 3 shows one of the blades of the flow structure according to FIG. 2 in detail; FIG. 4 shows a blade for joining to the base body in a longitudinal section; FIG. 5 shows another blade for joining to the base body in a longitudinal section;

FIG. 6 shows the positioning of the flow structure as an anti-turbulence structure in a schematic section.

PREFERRED EMBODIMENT OF THE INVENTION FIG. 1 shows a turbomachine 1 in a schematic view, specifically a mantle flow engine. The turbomachine 1 is divided functionally into compressor la, combustion chamber lb and turbine lc. Both the compressor 1a and the turbine 1c are each made up of several stages, each stage being composed of a ring of guide vanes and a rotor blade. During operation, the moving blades rotate around the longitudinal axis 2 of the turbomachine 1.

FIG. 2 shows a flow structure 20 which is made up of a base body 21 on which a plurality of blade leaves 22 are arranged. The flow structure 20 is produced by joining the blades 22 to the base body 21 . Schematically indicated joining beads 25 can be seen. FIG. 3 shows such a blade 22 in a detailed view. This is at a first end 31, which is joined to the base body 21, hollow-cylindrical, namely designed as a self-contained hollow cylinder. In the present case, the geometry is circular-cylindrical, ie there is rotational symmetry about a longitudinal axis 33 in a first section 32 at the first end 31 . The hollow-cylindrical shape is in a distal section 34 which adjoins the first section 32 open to one side, to the left in Figure 3. The closed, hollow-cylindrical shape thus transitions into a geometry that is essentially in the form of a half-shell. Relative to a revolution 36 around the longitudinal axis 33, the airfoil 22 in the distal section 34 is therefore only hollow-cylindrical over a segment 37 and is otherwise open.

FIG. 4 shows an airfoil 22 which, according to the present subject matter, is captured in the first section 32 with a wall thickness di which is greater than a wall thickness dhohi in the distal section 34 . The blade 22 can thus be reliably clamped in the first section 32 and joined to the first end 31 of the base body 21 by rotary or orbital friction welding. For this purpose, the first section has a length 45 of around 15 mm. The inner diameter 46 in the first section 32 can then be enlarged, in particular adjusted to the distal section 34, with a subsequent material-removing post-processing.

The airfoil 22 according to FIG. 5, in contrast to that according to FIG. This also allows reliable clamping and results in a large-area weld. In this variant, too, the joined blade can then be reworked in the first section 32 to remove material. In particular, a wall thickness d2 (indicated by dashed lines) can thus be achieved which essentially corresponds to the wall thickness dhohi in the distal section 34 .

Both the airfoil 22 according to FIG. 5 and that according to FIG. 4 can be produced beforehand, ie before joining to the base body 21, for example starting from a cylinder as a raw component. This can be done, for example, by machining, for example by turning and drilling, etc. In contrast to what is shown in FIGS. 4 and 5, the surface of the first section 32 that faces the interior of the respective airfoil 22 does not necessarily have to be flat. Furthermore, in contrast to what is shown in FIG. 2, additional recesses or holes can also be or will be introduced into the base body 21 . FIG. 6 illustrates the positioning of the flow structure 20 in the turbomachine, namely outside of its gas duct 60. In concrete terms, the flow structure 20 is provided radially inside the gas duct 60 with the blading 61 and serves as an anti-turbulence structure.

REFERENCE LIST

flow machine 1

compressor la

combustor lb turbine lc

Longitudinal axis (flow machine) 2

flow structure 20

Body 21

airfoils 22 joining bead 25

First end 31

First section 32

Longitudinal axis (blade) 33

Distal section 34 Circumference 36

segment 37

Length (first section) 45

Inside diameter (first section) 46

Full body 55 gas channel 60

blading 61

Claims

EXPECTATIONS

1. A method for producing a flow structure (20) for a turbomachine (1), in which at least one blade (22) is joined with a first end (31) to a base body (21), characterized in that the blade ( 22) in a portion (34) distal to the first end (31) over at least one segment (37) has a hollow cylindrical shape with a wall thickness dhohi; the airfoil (22) is gripped in a first section (32) in the region of the first end (31) when it is joined to the base body (21); and the airfoil (22) is designed either as a solid body (55) during the joining in the first section (32) or has a wall thickness di > dhohi.

2. The method according to any one of the preceding claims, wherein the joining is a friction welding.

3. The method according to claim 2, wherein the friction welding is a rotary friction welding or an orbital friction welding.

4. The method according to any one of claims 1 to 3, wherein the airfoil (22) after the joining to the first section (32) is processed by removing material.

5. The method as claimed in claim 4, in which a hollow-cylindrical shape is created with the material-removing machining in the first section (32) or an inner diameter (46) of the hollow-cylindrical shape is expanded.

The method of claim 5, wherein the airfoil (22) has a wall thickness d2 substantially equal to wall thickness dhohi after machining in the first section (32).

7. The method according to any one of the preceding claims, wherein the wall thickness dhohi is at most 5 mm.

8. The method according to any one of the preceding claims, wherein the first

Section (32) has a length (45) of at least 5 mm and at most 25 mm.

9. The method according to any one of the preceding claims, wherein the base body (21) and the airfoil (22) are provided from a disgusting Ni material.

10. The method as claimed in one of the preceding claims, in which the flow structure (20) is heat-treated after joining.

11. The method according to claim 10, in which a joining bead (25) is removed before the heat treatment.

12. The method according to any one of the preceding claims, wherein on the finished flow structure (20) produced a total of at least four and at most

20 blades (22) are provided.

13. Flow structure (20) for a turbomachine (1), which flow structure (20) has a base body (21) and a blade blade (22), which is joined with a first end (31) to a base body (21), wherein the airfoil (22) in a section (34) distal to the first end (31) has at least one segment (37) of a hollow-cylindrical shape with a wall thickness dhohi, based on a run around its longitudinal axis (33), wherein the airfoil (22) is also designed in a first section (32) at the first end (31) either as a solid body (55) or has a wall thickness di > dhohi.

14. Use of a flow structure (20) according to claim 13 in a flow machine (1).

15. Use according to claim 14, in which the flow structure (20) in the turbomachine (1), relative to its longitudinal axis (2), is arranged radially inside or outside the gas channel (60) of the turbomachine (1).