WO2011061192A1

WO2011061192A1 - Turbine or compressor blade

Info

Publication number: WO2011061192A1
Application number: PCT/EP2010/067581
Authority: WO
Inventors: Francois Benkler; Marco Link; Torsten Matthias; Marc Mittelbach; Marion Morthorst; Michael Rollmann; Horst Saathoff; Hubertus Michael Wigger
Original assignee: Siemens Aktiengesellschaft
Priority date: 2009-11-17
Filing date: 2010-11-16
Publication date: 2011-05-26
Also published as: US20120230829A1; EP2501901A1; EP2322763A1; EP2501901B1; JP2013510994A; ES2530053T3; RU2012124907A; PL2501901T3; CN102770623A; RU2517005C2; CN102770623B

Abstract

The invention relates to a blade for a turbine or a compressor, at least partially made of fiber-reinforced plastic, in particular carbon fiber reinforced plastic, being particularly durable under operating conditions. According to the invention, the blade (4) comprises a blade body (5) and a blade root (6). The blade body (5) is substantially made of a folded fabric web (7) made of fiber reinforced plastic, wherein a retaining loop (9) is formed in the area of the fold (8), and wherein a blade surface (11) is formed from the overlapping web ends (10). The blade root comprises a longitudinal beam (20) and at least two holders (25) for anchoring the blade (4) in a corresponding groove (3) of a rotor (2), said holders being preferably each fixedly connected to said beam at both ends. The blade body (5) is suspended on the beam (20) by means of the retaining loop (9).

Description

description

Turbine or compressor blade

The invention relates to a blade of a turbine or a compressor.

A blade of a turbomachine normally comprises on the one hand an aerodynamically curved blade and on the other hand a blade root which serves to anchor the blade in a corresponding groove of a rotor. The rotor equipped with blades is referred to below as a rotor.

As a comparatively new material for the production of blades, carbon fiber reinforced plastic (CFRP) is also currently being considered. The manufacture of CFK requires e.g. advantageously a lower weight of the blade. However, CFRP is disadvantageous

Pressure load comparatively less stable. Such compressive stresses occur on a blade e.g. in the region of the blade root within the groove by the action of a rotational centrifugal force.

For this purpose, for example, from US 4,037,990 a rotor blade made of a fiber composite material

Turbomachine known. The rotor blade is composed of a plurality of fibrous layers which form a common loop at its foot-side end. There are two of these loops for forming the blade root

intended. For fixing the rotor blade in one

Rotor disk is provided a long slotted bolt whose bolt elements extend through the respective loop. The bolt head and a screw on the bolt end screw nut firmly clamp the blade in an axial groove of the rotor. During operation of the turbomachine, the fibrous layers are pressed against the supporting flanks of the retaining groove due to the action of centrifugal force. Due to the However, in the layers occurring compressive stresses, the rotor blade is only limited shelf life. Furthermore, a rotor blade for gas turbines is known from US Pat. No. 2,992,975, which has a cylindrical, stiff core at the foot, around which a plurality of woven layers made of threads are looped. The situation will also change

Airfoil formed. To attach the rotor blade in a holding metal plates are provided on the core, which bear against the flanks of the retaining groove. Between the two metallic plates, a plastic filler material is provided to fill the space between the outermost layer and the retaining groove contour.

The invention has for its object to provide an at least partially made of fiber-reinforced plastic, in particular CFRP, manufactured blade for a turbine or a compressor, which is particularly durable, i. is durable. It is another object of the invention to provide a

Operating conditions particularly stable rotor with blades made essentially of fiber-reinforced plastic specified.

With regard to the blade, this object is achieved according to the invention by the features of claim 1. Thereafter, the blade comprises, in addition to an aerodynamically curved blade, a blade root with an elongate or pin-shaped support, which is manufactured in a preferred embodiment from metal. Furthermore, the blade root comprises at least two

Mounts, these preferably plate-shaped

Brackets on the carrier - at least in its radial direction - are fixed in position. Each bracket is for

Anchoring the bucket in a corresponding

formed like a hammer-shaped or fir tree-shaped groove of a rotor and can rest against the side walls.

The airfoil is essentially made of layered scrim webs of fiber-reinforced plastic, in particular CFRP, which (essentially between the holders) is guided around the carrier. In this case, the two webs ^projecting beyond the carrier are connected to each other in a planar manner to form a blade surface. The part of the airfoil which is led around the carrier forms a retaining loop for suspending the airfoil on the carrier. In terms of manufacturing technology, it is preferably provided initially to use the scrim for shaping the airfoil (that is, the airfoil surface and the airfoil)

Halteschlaufe), and the so-manufactured

Then lift the blade onto the carrier.

Alternatively, of course, the scrims may also be applied around the wearer to form and shape the adjoining airfoil. In the intended mounting situation of the blade, this lies with its blade root, i. with the retaining loop of the blade and the carrier therein arranged in the groove of the rotor, while the airfoil substantially protrudes - with respect to the rotor - radially out of the groove.

Since the airfoil is suspended from the carrier by means of the retaining loop, rotationally induced centrifugal forces acting on the blade are absorbed substantially via the carrier. A direct force transmission between the blade and the rotor groove does not take place, or only to a comparatively small extent. Therefore, the blade or its clutches is mostly under tension.

Since fiber-reinforced plastic is much more resistant to tensile loads than to compressive or shear loads, the blade and in particular its attachment area in the form of the blade root is therefore particularly resistant to long-lived operating conditions. Advantageously, opens up the use of fiber-reinforced plastic, in particular CFRP, for the preparation of the actor ^¬ felblatts generally possible to construct a particularly favorable aerodynamic airfoil. This carries thus at a reduced energy input, which in turn is advantageously associated with a reduced evolution of C02, at. Due to the lower weight of the fiber-reinforced plastic, the blades of such blades can also be larger than blade blades of metallic blades, with the same blade root. This also allows an increase in the mass flow.

The individual mounts of the blade root are for

Stabilization of the same by at least one edge part connected to each other, this being aligned substantially parallel to the carrier.

In this case, two flank parts are preferably provided, which are each attached to the two side edges of each of the holders, with which the respective holder projects beyond the blade. Accordingly, the two flank parts are preferably diametrically opposite with respect to the carrier. In particular, the attachment of the flank parts again takes place in such a way that they do not touch the scrim web, at least in the region in which the grips protrude beyond the airfoil. As a result, the unwanted compressive stresses in the scrim passes safely avoided. For trapezoidal brackets are the

Flank parts preferably attached to the two legs of the trapezoid, so that the power flow completely over the

Flank parts is done. This reduces the end-side

Strain of the holding enormous and thus equalizes the load in the rotor disk due to the

Flank parts significantly enlarged contact surfaces. As a result, the jaws located between two adjacent retaining grooves can be downsized, resulting in a compact

space-saving arrangement of retaining grooves in the rotor is possible. In a particularly preferred embodiment of the invention, each of the holders in the region of the carrier protrudes on both sides beyond this at least substantially at right angles to the longitudinal extension of the blade. In other words, In such configurations, the supports in the region of the suspension of the airfoil extend on both sides beyond the scrim web, so that the scrim, at least in the local area, does not come into contact with the corresponding side surfaces of the groove (the groove flanks). Consequently, under centrifugal force, the blade mainly abuts only on the brackets on the groove flanks and not on the scrim, so that only the brackets experience compressive stresses. This avoids compressive stresses in the foot-side jaw regions, which could occur due to the centrifugal force effect, if the foot-side scrim would touch the groove flanks.

Conveniently, each of the brackets also protrudes on the intended radially inner (facing away from the blade surface) side of the blade beyond the blade, so that the scrim web is suspended without contact in the groove bottom of the rotor groove.

In a further embodiment of the invention, the blade root comprises two holders, in particular attached at the end of the carrier, and at least one third holder, which is fixed in position on the carrier spaced apart in the longitudinal direction of the carrier for each of the two end-mounted holders. Preferably, these additionally provided brackets are evenly distributed over the length of the carrier. In this embodiment, the airfoil is expediently made of a plurality of scrim-webs, which are each suspended between two brackets on the carrier and thus fix the position of the central brackets in the longitudinal direction of the carrier. In principle, the two

Fastening positions of the brackets on the elongated support selected depending on the center of gravity of the bucket, so that even a non-end, but still in the field of

Carrier ends arranged mounting position of the brackets can be useful.

Preferably, each of the holders is provided with a passage corresponding to the cross section of the carrier, through which the carrier is inserted in each case substantially fit. Optionally, the carrier with the brackets ver ^¬ welded. Conveniently, the flank parts are each positively or materially - preferably plugged or welded - connected to the brackets.

The support is preferably round or substantially triangular in cross-section. In a triangular shape, an isosceles triangle, in particular with rounded edges, is preferred, wherein the edge enclosed by the two legs in particular faces approximately the blade surface of the blade leaf.

Preferably, the support is provided on its surface with a sliding layer, in particular with a layer of polytetrafluoroethylene. As a result, if necessary, the innermost jelly web can slide relative to the carrier.

The clutch is formed in an advantageous embodiment of the invention substantially unidirectional, wherein it has a main fiber direction, which is aligned substantially along an operational centrifugal force direction. The blade is thus particularly stable against the resulting tensile forces. Additionally or alternatively, the scrim is reinforced in the region of the blade root or in the region of the carrier by a three-dimensional interweaving of the fibers.

Conveniently the airfoil, at least in the region of its blade surface, see, comparable to its surface with a Erosi ^¬ onsschutzschicht, in particular of a particle composite or a surface coated with a hard material metal foil. This layer advantageously also improves the resistance of the blade to the ingress of water. With respect to the rotor above-mentioned object is achieved according to Inventive ^¬ by the features of claim 12. Thereafter, the rotor comprises a rotor, in which at least one groove is introduced and at least one of the previously registered loading, the inventive blades. The blade is fixed in position with its blade root in the groove.

Due to the comparatively low weight of the blades made essentially of fiber-reinforced plastic, each of the grooves provided in the rotor is advantageously made comparatively small. In addition, the entire runner is advantageously particularly light. Of course, the blade root to the blade can be made disproportionately large, if the blade according to the invention in a turbocharged Betriebskeansprüht a purely made of metal or stainless steel blade to replace.

Preferably, the groove and the brackets are matched to one another such that the brackets are respectively supported on the side surfaces of the groove. In particular, the brackets essentially fill the groove cross-section in an expedient manner.

Preferably, both the brackets and the groove are formed in cross-section substantially trapezoidal

Other cross-sectional shapes, such as a "fir-tree shape" or semi-circular shapes, are also possible for mounts and groove cross-sectional contours. In an advantageous embodiment of the invention, the supports of the blade are congruent to each other, wherein the groove has a uniform width and shape over its length. In a preferred embodiment of the rotor this includes a plurality of each substantially axially aligned, evenly distributed over the circumference grooves, in particular in each groove in each case a blade used and there is fixed in position. In an alternative to this, a circumferential groove is introduced into the rotor of the turbine or compressor rotor, wherein a multiplicity of blades are accommodated in a row in this groove and fixed there.

Two embodiments of the invention will be explained in more detail with reference to a drawing. In the drawings: FIG 1 in a cross section of a first embodiment ei ^¬ nes turbine rotor having a turbine blade comprising an airfoil and a blade root, FIG 2 is a schematic exploded view of the

Shovel foot according to the first embodiment, and FIG 3 in illustration according to FIG 2, the blade root according to a second embodiment.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

FIG. 1 shows a turbine rotor 1 in a slightly schematized sectional representation. The turbine rotor 1 comprises a rotor 2 made of stainless steel, in which a multiplicity of axial grooves 3 are uniformly distributed over the circumference. In FIG. 1, only a section of the rotor 2 is shown in the region of a single axial groove 3. In the first embodiment shown here, each axial groove 3 is designed substantially as a so-called dovetail groove. In the axial groove 3, a turbine blade 4 is received.

The turbine blade 4 comprises an airfoil 5 (shown only partially here), as well as a blade root 6, which serves for anchoring the turbine blade 4 in the axial groove 3. The airfoil 5 is made of several superimposed

Lanes 7 containing predominantly unidirectional CFRP gefer ^¬ Untitled. The webs 7 are folded in such a way-preferably approximately in the middle-that in the area of the folds which result during folding. the fold 8 a retaining loop 9 is formed. Beyond this retaining loop 9 (in the illustration above) the web ends 10 lie flat against each other, being "baked" under shaping to form a blade surface 11 of the blade 5. The blade surface 11 protrudes approximately radially out of the axial groove 3 of the rotor 2.

A major fiber direction of the CFRP sheeting is oriented approximately along the tracks 7 so that each carbon fiber 12 of the CFRP sheeting is oriented substantially parallel to the longitudinal sectional surface of the airfoil 5 (substantially also each forming a loop).

At its - in the manufacturing state shown here - the outer soapy surface 13, the blade 5 is coated with an erosion protection layer 14. Alternatively, the erosion protection layer 14 is provided only in the area of the blade surface 11. The blade root 6 comprises on the one hand as a carrier an elongated metal core 20, which rests in the retaining loop 9 for suspending the blade 5. The structure of the blade root 6 is explained in more detail with reference to a three-dimensional exploded view of FIG 2. It can be seen that the metal core 20 is formed by a round rod made of stainless steel. The surface 21 of the metal core 20 may be provided with a sliding layer 22, for example made of PTFE. At its two ends 23, 24 is the

Metal core 20 each connected to a holder 25. The two brackets 25 are essentially formed by congruent, isosceles, trapezoidal steel plates, which are corresponding to the dovetail-shaped axial groove 3 inserted into this. Each holder 25 has approximately in its center of area a circular passage 26, in which the metal core ^¬ 20 is inserted substantially accurately, the Brackets 25 projecting approximately at right angles to the metal core 20 over this.

At the two legs 27 of each holder 25 each have a peripheral recess 28 is inserted into this. These recesses 28 are used for fixing two flank parts 30, with which the two brackets 25 are connected to the legs 27 in the assembled state. Each flank part 30 is essentially formed by a ^rectangular , elongated steel plate. Each flank part 30 has on a side surface 31 a bulge 32, which extends in each case over the entire length of the corresponding flank part 30. The bulges 32 are each formed complementary to the recesses 28, so that the flank parts 30 with the bulges 32 in the recesses 28 are fixable in position.

Each flank part 30 furthermore has a slightly angled longitudinal edge 33. In this case, each flank part 30 is dimensioned such that the straight part of the side surface 31 has a width b which corresponds approximately to the leg length L of the brackets 25. In the assembled state, the flank members 30 are mounted on both sides of two legs 27 of the two brackets 25, preferably welded. In each case with a side edge 34 opposite the edge 33, the edge parts 30 are arranged approximately flush with the long trapezoid side 35, the angled edge 33 protruding beyond the legs 27 on the short trapezoid side 36 in each case.

It can be seen from FIG. 1 that the protruding edges 33 essentially serve to hold the blade 5 in the tangential direction in the assembled state.

It is further apparent from FIG. 1 that a mean width B (FIG. 2) of each of the holders 25 is dimensioned sufficiently large that it is in the region of the metal core 20 or the retaining loop 9, substantially at right angles to the blade surface 14 on both sides of the blade 5, so in particular in each case via the scrim webs 7,

protrudes.

As a result, in particular radially at the level of the metal core 20 or the retaining loop 9, there is no contact between the flank parts 30 and the CFK scrim webs 7. Thus arises in this area even under the action of an operating during the turbine rotor 1 resulting (radially acting on the rotor) centrifugal force F no disadvantageous for the CFRP scrim pressure load.

During operation, the blade 5 therefore aligns with the centrifugal force F, as a result of which the blade 5 is almost exclusively under tensile load, against which the CFRP clutch is particularly resistant, in particular because of the favorable main fiber direction. In the embodiment shown here, the two flank parts 30 are welded to the rotor 2 in the axial groove 3.

In FIG. 3, the blade root 6 according to a second embodiment of the turbine rotor 1 or the turbine blade 4 is shown. The second embodiment substantially corresponds to the first embodiment. In contrast, the blade root 6 has a third holder 25 here for more favorable load transfer, which is arranged approximately centrally in the longitudinal direction of the metal core 20. This middle bracket 25 is constructed analogously to the end-side brackets 25, wherein the metal core 20 is inserted through the passage 26 therethrough. The airfoil 5 is formed here by two-part webs 7. In the region of the holding loops 9, the webs 7 are each arranged in the longitudinal direction of the metal core 20 between the holders 25, wherein they additionally Suspension of the blade 5 also serve for axial fixation of the middle bracket 25.

An embodiment with four or more brackets 25 is also conceivable.

Claims

A blade (4) for a turbine or a compressor, comprising an airfoil (5) and a blade root (6),

- Wherein the airfoil (5) is essentially made of a folded scrim web (7) made of a fiber-reinforced plastic, wherein in the region of the fold

(8) a retaining loop (9) is formed, and in which from the superposed track ends (10) has a

Shovel surface (11) is formed,

- Wherein the blade root (6) an elongate carrier (20), and at least two each fixed in position with this associated holders (25) for anchoring the blade (4) in a corresponding groove (3) of a turbine rotor (1), and

- Wherein the blade (5) by means of the retaining loop

(9) is suspended on the support (20),

characterized in that

the individual holders (25) are connected to each other for stabilization by at least one flank part (30), and this is aligned essentially parallel to the carrier (20).

Shovel (4) according to claim 1, wherein each of the holders (25) in the region of the carrier (20) protrudes on both sides at least substantially transversely to the longitudinal extent of the blade (5).

The blade (4) according to claim 1 or 2 with at least one third bracket (25) for anchoring in a corresponding groove (3) ^¬ brought in the longitudinal direction of the carrier (20) to each of the two, in particular end side, brackets (25) spaced fixed to the carrier (20) is fixed in position.

A blade (4) according to any one of claims 1 to 3,

wherein the flank part (30) form-fitting or

Cohesively connected to the brackets (25) Blade (4) according to one of the preceding claims, with two flank parts (30) which are each attached to the side edges ^¬ (27) of the two on the blade (5) protruding portions of the brackets (25).

A blade (4) according to any one of claims 1 to 5, wherein the support (20) is round or substantially triangular in cross-section.

A blade (4) according to any one of claims 1 to 6, wherein the carrier (20) is made of metal.

Blade (4) according to one of claims 1 to 7, wherein the support (20) is provided on its surface (21) with a sliding layer (22).

A blade (4) according to any one of claims 1 to 8, wherein the scrim (7) is formed substantially unidirectionally, and wherein the main fiber direction of the scrim is aligned as much as possible along an operational centrifugal force direction.

Blade (4) according to one of claims 1 to 9, wherein the blade (5) is at least partially provided on its surface (13) with an erosion protection layer (14).

A blade (4) according to any one of claims 1 to 10,

wherein the fiber-reinforced plastic is formed as a carbon fiber reinforced plastic (CFRP).

Rotor (1) with a rotor (2), in which at least one groove (3) is introduced, and with at least one blade (4) according to one of claims 1 to 11, wherein the blade root (6) of the blade (4) in the groove (3) is an ^¬ , and wherein this fixed in position in the groove (3), with the rotor (2) is connected.

13. runner (1) according to claim 12, wherein the holders (25) and / or the flank parts (30) to the

Support side surfaces of the groove (3).

14. rotor (1) according to claim 12 or 13, wherein the holders (25) substantially fill the groove cross-section.

15. Rotor (1) according to any one of claims 12 to 14, wherein both the groove (3), and the holders (25) are substantially trapezoidal in We ^¬ sentlichen.