EP1730389B1 - Device for supplying cooling air to a moving blade - Google Patents

Abstract

An arrangement is disclosed for the admission of cooling air to the internal walls of a component rotating about a rotation axis, such as a moving blade in a rotary machine. A component root can be fastened to a rotor unit in a rotationally fixed manner and adjoining in a radially extending manner is a one piece component airfoil in which at least one radially extending cooling passage region (K1) is provided which, in the region of the component root, opens out via an opening into a cooling-air supply passage passing at least partly through the component root longitudinally relative to the rotation axis. A distribution plate forms a fluid-tight connection with an opening margin, surrounding the opening of the cooling passage region (K1), at least during the rotation of the component about the rotation axis. The distribution plate provides at least one through-opening in the region of the opening of the at least one cooling passage region (K1), through which through-opening cooling air passes from the axial cooling-air supply passage into the radial cooling passage region (K1).

Description

State of the art

The invention relates to a device for Kühlluftbeaufschlagung a blade as defined in the preamble of claim 1. Such a device is for example from the EP-A-0 340 149 Rotary machines, for example turbo or compressor stages of gas or steam turbine plants, generally have fixed guide vanes and rotor blades rotating about an axis of rotation for targeted expansion or compression of gases or gas mixtures, which are usually exposed to high process temperatures and thus have to withstand high thermal loads , In addition to the thermal load, it is in particular the rotating about the axis of rotation blades, which are also exposed to high, caused by the centrifugal forces mechanical loads.

In an attempt to improve the efficiency of such heat engines, measures are usually taken by the rotating components are always exposed due to increasing process temperatures and increased rotational speeds thermal and mechanical loads. However, these efforts are due to the materials used, from which especially the rotating system components are made, set physical load limits. However, in order to be able to make further optimizations in terms of efficiency, ways are sought, in particular to effectively cool the system components exposed to heat and subjected to centrifugal force. For this purpose, a number of proposals is already known with which blades in rotary machines with Cooling air to be applied. Typically, such a trained blade for purposes of their rotor-side attachment to a pine cone-like structured blade root, to which radially adjoins the blade blade. For cooling purposes, the blade root is preferably interspersed with a plurality of radially-oriented cooling passages which extend innately through the entire extension of the blade blade for effective cooling of the blade. For cooling air supply serve cooling air supply channels provided on the rotor side, is fed by the cooling air into the rotor blade radially passing through the cooling channels. Such a cooling air supply system thus requires a rotor having a plurality of radially oriented cooling air ducts, the individual cooling ducts of which must be exactly aligned by appropriate positioning of the individual rotor blades in alignment with the radial cooling ducts provided in the rotor blade root. Even the slightest misalignments between the blade root and the rotor unit can permanently impair effective cooling of the blade, which is considerably reduced by the life of the blade.

As an alternative to the radial supply of cooling air to a blade via a rotor-side cooling air supply system, it has been proposed to make the cooling air supply via a cooling air supply channel axially penetrated through the rotor blade root. In this case, a cooling air feed stream enters the axially oriented cooling air supply channel within the blade root, from which branch off individual cooling air channels projecting radially into the blade airfoil. Since blades are usually produced as part of a casting process, it is used to form such in a casting inside cavities of the so-called Gusskem technique, which allows in particular the rotor blade axially projecting through the cooling air supply duct and the individual, the blade inside radially at least partially enforcing individual cooling channels to produce. It will be appreciated, however, that for an optimized distribution of the cooling air feed stream within the axially oriented cooling air supply passage, flow passages are provided which provide the axially directed cooling air feed stream into the radially extending cooling passages to redirect within the blade. However, due to the manufacturing process, the flow gaps to be provided for this purpose, which cause both a change in direction and also a flow distribution of the cooling air feed stream directed axially into the blade root, are subject to production-related structural tolerances by which precise guidance and division of the cooling air flow onto the individual cooling ducts extending radially along the blade airfoil only occur an unsatisfactory accuracy is possible.

Here, the invention is intended to remedy the situation, so that the invention is based on the object to optimize the cooling air distribution to the individual radially oriented cooling channels within a blade. Also, the measures to be taken for this purpose should not cause costly manufacturing or assembly steps and have robust properties that can withstand the high demands in terms of thermal and mechanical stress within such about a rotation axis rotating components.

Presentation of the invention

The solution of the problem underlying the invention is specified in claim 1. Advantageous developments are the subject of the dependent claims and the description with reference to the exemplary embodiments.

For ease of illustration and description of the inventive concept, the further embodiments relate to the case of a blade which is mounted along a rotor unit of a gas or steam turbine plant and can be used in a turbo stage or compressor stage. Of course, should not be limited by this reference, the general inventive concept, which also relates to altemaive plant components that are exposed to comparable loads.

The distribution plate, which is preferably made of temperature-resistant flat material, provides passage openings along its extent corresponding to the radially extending cooling channel regions, in each case with opening diameters through which the volume flow of cooling air which can be predetermined in the individual cooling channel regions. With the aid of the distribution plate, it is thus possible to divide previously calculated volume proportions of cooling air, which are adapted to the respective rotating blade, onto the individual cooling channel regions extending radially along the blade airfoil. Such an exact division of the cooling air flow is not possible due to the manufacturing tolerances unavoidably associated with the casting process, with the exclusive use of flow-related profiles produced by casting.

In order to minimize the assembly effort for introducing the distributor plate along the cooling supply channel axially extending through the component foot and at the same time to create conditions for an exact seating and exact positioning of the distributor plate relative to the at least one radially extending cooling channel region Cooling air supply ducts provided at least two axially spaced apart shoulder elements, the radially opposite the opening edge of the opening of the at least one cooling channel region slightly spaced, and with this limits an insertion slot, in the axialwärtiges insertion into the cooling air supply duct, the distribution plate experiences a preferably flush snug fit. It should be noted at this point that it is preferable to provide a plurality of cooling channel regions which pass radially through the rotor blade and are separated from one another by intermediate walls. In the area of the cooling air supply channel extending axially in the blade root, the intermediate walls open via a respective opening edge facing the cooling air supply channel, which encloses the opening of the respective cooling channel region extending radially inward. With this opening edge, at least in the state of rotation, it is necessary to create a fluid-tight connection to the distribution plate in order to completely exclude possible leakage flows between distribution plate and opening edge.

As a result of the rotationally independent, fluid-tight connection between distribution plate and the opening edge of the opening of the at least one radially extending cooling channel region, it is not necessary to have tolerance-free gap dimensions for the insertion slot which is delimited between the shoulder elements and the at least one opening edge. provide, a requirement that can not be met anyway with conventional casting.

To meet the requirement to provide at least during rotation for a fluid-tight connection between the distributor plate and the corresponding opening edges, it is the distributor plate made of a material and with a material thickness to manufacture, so that the bending moment of the distribution plate by the resulting by rotation and on The distribution plate attacking centrifugal forces is exceeded and the distribution plate is able to conform to the casting geometry of the opening edges downright. This nestling process can also be supported in a further preferred embodiment in that the distribution plate has locally limited material weakenings, for example in the form of mechanical indentations or cracks. Also, such material weakenings can be generated by deliberately changing the microstructure in the distribution plate. Such points of reduced strength are distributed along the distribution plate, preferably in areas near the opening edges where it is necessary to make a fluid-tight connection.

It may also be advantageous in some cases to have the distribution plate fixed at one end or both ends to the inner structure of the blade root in the area of the cooling air supply channel, for example by means of a soldered or welded connection. The joints required for this purpose are easily accessible for mounting purposes axially through the cooling air supply channel, so that the required assembly effort is not significantly increased.

Since, as will be explained in more detail below with reference to an embodiment, the axially extending through the blade root fully extending cooling air supply channel is open on both sides with respect to the blade root, it is necessary to close an axial-side opening fluid-tight.

A simplest embodiment provides, by corresponding bending of an end region of the distribution plate to provide a frontal closure of the cooling air supply duct, wherein the distribution plate at least in the region of its end bent-over plate portion with the inner wall of the Cooling air supply duct to be welded or soldered. A fixation in this regard, however, could adversely affect the required at least in the state of rotation adjusting fluid-tight connection between the distribution plate and the at least one opening edge, so that a further preferred embodiment instead of a fixed disposal of the distribution plate in the region of the bent Verteilplattenabschnittes a separate end plate provides , which closes the cooling air supply channel axially on one side fluid-tight. For this purpose, it is advisable to have the end plate adapted to the cross-sectional contour of the cooling air supply channel fluid-tight by means of soldered or welded connections with the blade root.

Brief description of the invention

Fig. 1

Querschnitt durch eine Laufschaufel einer Gasturbinenanlage,

Fig. 2

detaillierte Querschnittsdarstellung durch den Fussbereich einer Laufschaufel,

Fig. 3

Detaildarstellung bezüglich einer den Kühlluftversorgungskanal axialwärts gasdicht abschließenden Abschlußplatte,

Fig.4 a-d

Ansichten alternativ ausgebildeter Verteitplatten sowie

Fig. 5

Alternative Verteilplatte innerhalb eines Laufschaufelfusses.

The invention will now be described by way of example without limitation of the general inventive idea by means of embodiments with reference to the drawing. Show it:

Fig. 1

Cross section through a blade of a gas turbine plant,

Fig. 2

detailed cross-sectional view through the foot region of a blade,

Fig. 3

Detailed representation with respect to a cooling air supply duct axially closing gas-tight end plate,

Fig.4 ad

Views of alternatively formed Verteitplatten as well

Fig. 5

Alternative distribution plate within a blade foot.

Ways to carry out the invention, industrial usability

In FIG. 1 the cross-section through a blade 1 is shown, which is arranged rotatably about a rotation axis 2 of a rotor unit integrated in a gas turbine arrangement. The rotor blade 1 has a rotor blade root 3 which can be frictionally connected to the rotor unit (not shown) via a correspondingly formed joining contour (fir tree structure - not shown). Radialward joins to the blade root 3, the blade 4, in the interior of which cooling channel areas K1 to K4 are provided. In the region of the blade root 3 extends an axially, ie parallel to the axis of rotation 2, oriented cooling air supply channel 5, which first extends through the entire axial width of the blade root 3. In the interior of the cooling air supply channel 5 so-called shoulder elements 6 are provided, which are machined out of the casting material by means of the casting process, with which the entire blade 1 can be produced, from which the remaining blade material is made. The shoulder elements 6 have upper surface portions 61 which are slightly spaced from each other on the radial side so-called opening edges 71. The opening edges 71 surround openings 7 facing the cooling supply channel 5, to which the cooling channel areas K1 and K2, which are bounded in each case by cooling channel area walls 72, adjoin the radial side. Similarly, the cooling supply channel 5 and provided in the interior of the provided in the blade blade cooling channel areas K1 to K4 in the way of casting, by providing a suitably modeled displacement core, which serves as a placeholder for the respective cavities and is introduced during the casting process in the mold.

For the flow guidance but in particular for the flow dimensioning of the cooling air flow passing through the cooling channel areas K1, K2, K3 and K4, a distribution plate 8 is provided in which appropriately positioned and dimensioned passage openings 81 are introduced. The passage openings 81 are correspondingly provided in the opening region of the openings 7.

In the illustrated embodiment according to FIG. 1 it applies the axially fed via the cooling air supply duct 5 cooling air supply flow targeted in the Feed cooling duct areas K1 and K2. The passage openings 81 provided in the opening region of the cooling channel region K1 allow a cooling air flow on the radial side through the cooling channel K1, which provides an outlet opening A at the upper flank of the blade 4, through which the cooling air escapes into the hot gas channel H. In contrast, the cooling air entering through the passage openings 81 into the cooling channel region K2 is for the most part diverted through corresponding flow guiding means 9 into the cooling channel region K3, which is adjoined by the cooling channel region K4 in the flow direction (see flow arrows). In the connecting region of the cooling channel region K3 and K4, the distribution plate 8 ensures that the cooling air flow flowing downwards in the cooling channel region K3 is deflected in its entirety into the cooling channel region K4 extending radially upwards. For this purpose, it is necessary that the distribution plate 8 gas-tight or fluid-tight against the corresponding opening edges 71 and the edge contour 10 hugs. At the same time, care must be taken to ensure that no leakage flows occur between the distribution plate 8 and the opening edges 71. In order to ensure this, it is necessary to dimension the distribution plate 8 and to select in terms of their plate material that it is firmly pressed flush with the corresponding opening edges 71 and the edge contour 10 of the centrifugal forces caused by the rotation about the rotation axis 2. The distribution plate 8 lies loosely in the between the surface portions 61 of the shoulder elements 6 and the opening edges 71 and the edge contour 10 limited entrance slot 11 (see FIG. 2 ).

For a one-sided axial, gas-tight completion of the cooling air supply channel 5 provides a cover plate 12 which is fixed to the blade root 3 by means of a welded or soldered connection has.

FIG. 2 As already mentioned, the shoulder elements 6 present in the interior of the cooling tuft supply channel 5 and the individual cooling channel areas K1 to K4, ie the cooling channel area walls 72 with the corresponding opening edges 71, are obstructed the casting process produced together. The opening edges 71 enclose with the surface portions 61 of the shoulder elements 6 an insertion slot 11, along which the distribution plate 8 which is planar in shape in the initial state can be pushed in axially. After insertion of the distribution plate 8 in the in FIG. 2 form shown within the cooling air supply duct 5, the end portions of the distribution plate 8 in the in. For substantially axial and radial fixation of the distribution plate 8 within the insertion slot 11 FIG. 2 bent manner indicated. The distribution plate 8 otherwise remains lying loose on the surface portions 61 of the shoulder elements 6. To the cooling air supply channel 5 on one side axially close fluid-tight, a cover plate 12 to the in FIG. 2 used left inlet opening in the cooling air supply duct 5 and welded or soldered in edge regions with the blade root 3. Due to the one-sided, gas-tight closure of the cooling air supply duct 5, the cooling air feed flow S entering from the right side into the cooling air supply duct 5 experiences a stowage effect within the cooling air supply duct 5, whereby the cooling air feed stream S is driven through the passage openings 81 provided in the distribution plate 8. Size and arrangement of the individual passage openings 81 define the volume flow of the cooling air flow entering the respective cooling passage areas K1 and K2. As a result of the fluid-tight, intimate connection formed between the distribution plate 8 and the edge regions 71 during rotation, which surround the respective openings 7 of the cooling channel regions K1 and K2, any leakage flows that could form between the distribution plate 8 and the edge regions 71 are prevented. In this way, it is ensured that the cooling air flow is guided loss-free exclusively along the cooling channel regions K1 to K4 provided in the interior of the blade airfoil.

FIG. 3 shows a further detail of the fluid-tight welded to the axial end portion of the cooling air supply duct 5 end plate 12. The end plate 12 is seated in a corresponding counter-contoured recess 13 within the blade root 3 and is welded fluid-tight with this. Likewise from the picture representation in FIG. 3 can be seen that the Distribution plate 8 loosely within the insertion slot 11 rests on the shoulder element 6. Only in the way of rotation and the resulting centrifugal forces the distribution plate 8 is raised radially and thus comes into contact with the edge contour 10, with which it enters into a corresponding fluid-tight connection. In this way it is avoided that cooling air can get back at this point from the cooling channel area K4 in the cooling air supply duct 5.

In the Figures 4 ad two different forms of training for a distribution plate 8 are shown. FIGS. 4a and b show a top and side view of a first distribution plate 8, the geometric dimensions of which are adapted to the insertion slot 11 described above. The distributor plate 8 is made of a heat-resistant flat material and initially designed for assembly purposes on one side flat (see FIG. 4a ). Furthermore, the distribution plate 8 has passage openings 81 whose arrangement, shape and size determines the cooling air volume which is conveyed through the cooling channel areas K1 to K4.

For assembly purposes, it is necessary to axially insert the distributor plate 8 formed on one side between the opening edges 71 and the surface portions 61 of the shoulder elements 6 and, after complete insertion into the cooling air supply channel 5 at an end portion 82 or 83 in the manner described above. See the page view in FIG. 4b , As already mentioned, the dimensions of the distribution plate 8 and the material are chosen such that at least local deflections on the distribution plate 8 in the region of the opening edges 71 may occur so that the distribution plate 8 can form a fluid-tight connection with the opening edges 71. In order to improve the bending capacity of the distribution plate 8, in particular in areas opposite to the opening edges 71, serve according to the embodiment in Figure 4c and d local material weaknesses in the form of notches 15 along the distribution plate 8 are provided. Due to the targeted local limited notches 15, the flexural rigidity of the distribution plate 8 at least locally be reduced in order to optimize local nestling of the distribution plate 8 to the opening edges 71. Likewise, the embodiment sees in FIG. 4 c and 4d each differently sized passage openings 81 for the cooling air supply into the cooling duct sections K1 and K2 before. Thus, the cooling passage area K1 is subjected to substantially less cooling air than the cooling passage area K2.

The measures described above are used for the preferred loose mounting of the distribution plate 8 within the cooling supply channel 5, wherein the distribution plate 8 is spatially fixed only within the insertion slot 11 on the one hand by the shoulder elements 6 and on the other hand by the opening edges 71 and the edge contour 10. Installation-consuming welding operations are completely avoidable in this way, but can be provided locally if required.

FIG. 5 shows a partial cross section through the foot portion 3 of a blade 1, which is formed according to the above embodiments. Along the Kühltuftversorgungskanals 5 only a single cooling channel area K1 is provided, to be shown in the cooling air from the cooling air supply duct 5 targeted. This follows via appropriately provided passage openings in the axially inserted distribution plate 8, which has at intervals along the distribution plate 8 on the bending capacity improving notches 14.

LIST OF REFERENCE NUMBERS

1

blade

2

axis of rotation

3

Moving blade root

4

airfoil

5

Cooling air supply duct

6

shoulder elements

61

surface section

7

opening

71

opening edge

72

Cooling duct partition

8th

distribution plate

81

Through opening

82.83

end

9

deflecting

10

edge contour

11

slot

12

End plate

13

recess

14

notches

Claims (17)

1. Arrangement for the admission of cooling air to the internal walls of a component rotating about a rotation axis (2), in particular a moving blade (1) in a rotary machine, having a component root (3) which can be fastened to a rotor unit in a rotationally fixed manner and adjoining which in one piece in a radially extending manner is a component airfoil (4) in which at least one cooling passage region (K1) extending radially longitudinally with respect to the rotation axis (2) is provided which, in the region of the component root (3), opens out via an opening (7) into a cooling-air supply passage (5) passing at least partly through the component root (3) longitudinally relative to the rotation axis (2), and a distribution plate (8) is provided in the region of the cooling-air supply passage (5) in such a way that the distribution plate (8) forms a fluid-tight connection with an opening margin (71), surrounding the opening (7) of the cooling passage region (K1), at least during the rotation of the component about the rotation axis (2), and provides at least one through-opening (81) in the region of the opening (7) of the at least one cooling passage region (K1), through which through-opening (81) cooling air passes from the axial cooling-air supply passage (5) into the radial cooling passage region (K1) characterized in that at least two axially spaced-apart shoulder elements (6) are provided inside the cooling-air supply passage (5), these shoulder elements (6) in each case being arranged radially opposite an opening margin (71) and enclosing with the latter a push-in slot (11) intended for the distribution plate (8).
2. Arrangement according to Claim 1, characterized in that the component can be produced by a casting process in which the cooling-air supply passage (5) passing axially through the component root (3) and the at least one cooling passage region (K1) oriented radially in the component airfoil (4) can be produced by means of the core technique.
3. Arrangement according to Claim 1 or 2, characterized in that the opening margin (71) surrounding the opening (7) is a surface region which encloses the opening (7) and has a surface plane coinciding with the opening plane.
4. Arrangement according to Claim 3, characterized in that at least two cooling passage regions (K1, K2) are provided, the opening margins (71) of which lie in a common surface plane, with which the distribution plate (8) forms a fluid-tight connection at least during the rotation of the component about the rotation axis (2).
5. Arrangement according to Claim 3 or 4, characterized in that the opening plane of the opening (7) is oriented perpendicularly to the radial direction predetermined by the rotation about the rotation axis (2) .
6. Arrangement according to one of Claims 1 to 5, characterized in that the cooling-air supply passage (5) passes axially completely through the component root (3), and in that the distribution plate (8) can be pushed completely into the cooling-air supply passage (5) at least on one side.
7. Arrangement according to Claim 6, characterized in that the distribution plate (8) provides at least one bent-over end region (82, 83) in the state inserted in the cooling-air supply passage (5).
8. Arrangement according to one of claims 1 to 7, characterized in that the distribution plate (8) is made of a flat metallic material.
9. Arrangement according to one of Claims 1 to 8, characterized in that the distribution plate (8) rests loosely on the shoulder elements (6), and a fluid-tight connection between the distribution plate (8) and the opening margin (7) is effected by a frictional connection which occurs due to centrifugal forces which are caused by the rotation and which act on the distribution plate (8).
10. Arrangement according to Claim 9, characterized in that the material and material thickness of the distribution plate (8) are selected in such a way that the distribution plate (8) conforms in a locally limited manner to the surface contour at least in the region of the opening margin (71).
11. Arrangement according to one of Claims 1 to 10, characterized in that the distribution plate (8) is produced from a flat or round material.
12. Arrangement according to one of Claims 1 to 8, characterized in that the distribution plate (8) is fixedly joined inside the cooling-air supply passage (5) at least in a locally limited manner, preferably by means of a brazed or welded joint.
13. Arrangement according to one of Claims 1 to 12, characterized in that the distribution plate (8) has locally limited material weak points.
14. Arrangement according to Claim 13, characterized in that the material weak points are designed in the form of mechanical notches (14) or cracks or by changing the structure in the distribution plate (8).
15. Arrangement according to one of Claims 1 to 14, characterized in that the cooling-air supply passage (5) is closed off in a fluid-tight manner by a closing plate (12) at least on one side.
16. Arrangement according to Claim 15, characterized in that the closing plate (12) is welded or brazed to the component root (3) after the distribution plate (8) has been inserted into the cooling-air supply passage (5).
17. Arrangement according to one of Claims 1 to 16, characterized in that the component is a moving blade of a compressor or turbine stage in a steam or gas turbine plant.

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