EP0926311B1 - Rotor for a turbomachine - Google Patents

Description

Technical field

The invention relates to a rotor of a turbomachine, which on a Surface of its rotor shaft in one or more rows of blades and / or other parts, for example. Heat shields or heat accumulation segments, each of which a foot protruding through the surface into the rotor shaft.

State of the art

With regard to the increase in performance and service life of modern gas turbines, the individual components of which are exposed to very high thermal loads cooling from the thermally highly stressed units always plays a role more important role. In particular, the cooling of the rotor and of the blades of a gas turbine, the one coming from the combustion chamber Hot gases are directly exposed and therefore a great cooling intensity needed.

In addition to known cooling measures, for example part of the pre-compressed air To branch off cooling purposes - which, however, due to the limited air balance in a modern gas turbine with inevitable loss of efficiency is connected -, it is alternatively proposed to cool the thermally stressed To accomplish aggregates of a gas turbine with other cooling media, for example to be subjected to cooling steam in a cooling circuit inside the rotor, for cooling all hot regions.

GB-A-742 242 describes a rotor for a turbine which is made of has several composite disc wheels composite shaft. Air chambers are formed between the disk wheels, which pass through air supply channels be supplied with fresh air from outside. On the circumference of the disc wheels blades are used with their feet, being below the feet of the blades Cavities are formed which are connected to the air chambers, so that at least the feet of the blades are supplied with a cooling medium. In the document EP-A-0 037 897 a gas turbine with a device for cooling the Described inside the gas turbine. The gas turbine consists of a rotor and a Stator. The cooling gas is introduced through an inlet channel into a buffer channel which it is withdrawn through an outlet channel into a buffer space located in the rotor becomes. An oblique hole leads from the buffer space to a fastening space for a blade root. Due to the oblique arrangement of the hole Cooling gas is transported to the blade root by centrifugal force.

The document DE-A-43 24 034 shows a gas turbine with one of several disks welded and bladed rotor. There are cavities between the panes educated. The cavity communicates with axial channels and is covered by a central cooling air supply coming from the downstream rotor end fed.

GB-A-810 459 describes a rotor of a turbomachine with an air-cooled one Shovel.

Presentation of the invention

In addition or as an alternative to the cooling devices mentioned above, the Invention based on the object, with the simplest possible means, the rotor and in particular the surface areas of the rotor shaft of a turbomachine and the radially arranged blades as directly as possible, but using a gentle cooling medium, preferably air. In particular, should the contours that are already present in known rotors are used for cooling purposes are, so that the cooling measures with little constructive as well as financial Use can be carried out. The measures according to the invention should also be retrofitted to turbomachines that are already in use can be.

This task according to the invention is corresponding with a rotor of a turbomachine the preamble of claim 1 solved in that over the circumference of the rotor shaft at least two feed-through channels are arranged adjacent, in one feed-through channel the cooling medium circulates radially outward from the cavity into a hollow channel and into the feed-through channel adjacent in the circumferential direction, the cooling medium from the hollow channel recirculated radially inward into the cavity.

The idea on which the invention is based is based on the consideration that the heat acting on the surface of the rotor shaft together with rotor blades hot gases flowing around the rotor, as close as possible to the peripheral peripheral edge the rotor shaft is to be dissipated directly by a suitable supply of cooling air to the Deflect the temperature of the rotor material and that of the rotor feet.

For this purpose, the rotors that are located just below their peripheral peripheral edge Have rotor shaft cavities with radial and / or oblique through channels provided so that the peripheral peripheral edge heated by the hot gases along with blades from the side of the cavity, which in turn has a cooling system with a cooling medium, preferably cooling air, is cooled can.

A rotor shaft contour known per se, which is used to carry out the inventive Measures are suitable, is shown in Fig. 2 as a representation of the prior art.

The highly schematic cross-sectional drawing according to FIG. 2 represents the represents the upper section of a rotor shaft 1 which rotates about the rotor shaft axis A. At the Peripheral peripheral edge of the rotor shaft are rotor blades radial to the rotor shaft axis 2 arranged. Between the blades are only for completeness the guide vanes 3 are shown, which are fixedly attached to the stator and in the spaces protrude between two successive blades 2. The over The arrow shown in the blade breaks represents the direction of flow of the hot gas through the turbines.

However, special attention should be paid to the center shown in FIG. 2 Section E should be placed near a blade root of a moving blade provides a cavity at the peripheral peripheral edge of the rotor shaft.

The idea of the invention basically provides the area of the rotor shaft above to perforate the cavity so that air exchange between the top of the Rotor shaft and the cooling air located in the cavity can take place. In particular the area of the rotor shaft must be provided with such a perforation so that the cooling air in the cavity directly touches the blade root area of the blades can cool.

Brief description of the invention

Fig. 1a

Teilquerschnittdarstellung durch einen Teil des peripheren Umfangsrandes einer Rotorwelle mit einem geschlossenen Hohlraum,

Fig. 1 b

Schnittdarstellung gemäß Schnittlinie A - A in Fig. 1 a,

Fig. 1 c

alternative Schnittdarstellung zur Figur 1 b und

Fig. 2

Prinzipquerschnittsdarstellung durch eine an sich bekannte Rotoranordnung.

The invention is described below by way of example without limitation of the general inventive concept on the basis of an exemplary embodiment with reference to the drawing, to which reference is expressly made with regard to the disclosure of all details according to the invention not explained in detail in the text. Show it:

Fig. 1a

Partial cross-sectional view through a part of the peripheral peripheral edge of a rotor shaft with a closed cavity,

Fig. 1 b

Sectional view along section line A - A in Fig. 1 a,

Fig. 1 c

alternative sectional view to Figure 1 b and

Fig. 2

Principle cross-sectional representation through a rotor arrangement known per se.

WAYS OF IMPLEMENTING THE INVENTION, INDUSTRIAL APPLICABILITY

The cross-sectional view shown in Fig. 1, which is only a section shows the rotor cross-section corresponds to a central section of one according to the invention stepped rotor, with the aid of the representation according to FIG. 2 the point is to be thought of which corresponds to the circle delimited by E in FIG. 2. The Circle preferably includes all those blade roots that with the invention "Perforation" can be detected.

The blade root 7 can be in a circumferential groove 8 or in an axial groove which is axial or extends obliquely axially on the surface of the rotor shaft 1. The circumferential groove 8 and / or axial groove and the blade root 7 can jags for mutual attachment exhibit.

On the surface 6 of the rotor shaft 1, the constant heat flow Q acts through the Hot gases flowing around the rotor. In addition, one penetrates through the blade root 7 Not shown in Fig. 1 blade, which is otherwise radially over the Surface 6 of the rotor shaft 1 rises, an additional heat flow Qs into the rotor shaft 1 a.

In order to remove the heat introduced into the rotor shaft 1 as quickly as possible, the provided according to the invention, the Schaufeffuß 7 of a moving blade, which in a Circulation groove 8 is fixed within the rotor shaft 1 with the aid of a feed-through channel 9 to be charged directly with cooling air. For this purpose, a cavity 5 is close to the Blade provided within the rotor shaft 1 and with a passage channel 9 connected such that the feed-through channel 9 is largely radial to Shaft axis A extends from the cavity 5 to the blade root 7. Moreover, it is the cavity 5 is connected to a cooling system 4, via which a cooling medium in the Cavity 5 can be fed. In the case shown in Figure 1 there is the cooling system 4 only from a supply 4a and a discharge channel 4b for the Cooling medium (see arrows that indicate the direction of flow of the cooling medium). Of course, several shovel feet can also be made from a cavity with feed-through channels are supplied with a cooling medium, for example two blade feet, as shown in the embodiment of Figure 1.

The supply 4a of the cooling medium into the cavity 5 is advantageously such that a swirl occurs in cavity 5 relative to the rotor. The return 4b of the heated Cooling medium from the cavity 5 is advantageously carried out on the inner surface of the cavity because the heated cooling medium collects there. The opening of the feed channel 4a into the cavity 5 must e.g. with large radii or bevels or guide vanes in such a way that the cooling medium flows in well can. If the latter is too warm for the rotor, the discharge duct 4b can always be used still isolate, e.g. through a lining pipe or a thermal insulation layer.

The circumferential groove 8 in which the blade root 7 is fastened also has a hollow channel 10 on, in which the cooling air present in the cavity 5 via the duct 9 can reach.

The circumferential groove 8 runs completely angularly around the rotor shaft 1, in which a plurality are arranged one behind the other. The individual hollow channels 10 under each blade root of a moving blade together form a circumferential channel 10 'through which the cooling air introduced via the duct 9 circulates can. In this way, an integral cooling system that cools the blade feet is inside the rotor shaft can be realized.

In addition to the through channels that cool the feet 7 directly 9 further feed-through channels 9 'are also provided which cover the peripheral area the rotor shaft completely or only partially. That way the heat flow Q acting on the peripheral peripheral edge 6 directly through the feed-through channels 9 'in the direction of the cavity 5 are provided in the cooling air is derived.

In addition to the feed-through channels 9, 9 'oriented in radial extension alternatively or in addition, oblique through-feed channels into the rotor shaft be introduced.

The cooling arrangement shown in Fig. 1, preferably for Cooling the rotor blades in the middle of the rotor can be done in different ways Be designed so that the cooling air for removal of the the existing blade heat is used.

Basically, the cooling air located near the blade root in the hollow duct 1 0 warms due to the large heat input and experiences in the presence of the by the rotation of the rotor generated centrifugal field so much lift that the warmer air directed radially inward climbs through the duct this gives way to the incoming colder air, so that it is called hot Shovel feet can cool. This convection flow that forms in the centrifugal field arises automatically due to the temperature gradient. The Feedthrough channels must, however, be made correspondingly large, so that countercurrent system within a channel as described above can train.

The openings of the feed-through channels, which end in the cavity 5, should open a smaller radius, measured from the axis of rotation of the rotor, than the areas of the rotor shaft where the heat is applied.

Furthermore, the design of the cavity can be designed as desired. So it is not mandatory required that the upper contour of the cavity from which the feed-through channels 9 go out, runs obliquely to the rotor shaft axis A. They can also Feed-through channels 9 also depart from cavity wall sections that are vertical or run vertically relative to the rotor shaft axis A. Essential with the arrangement of the feed-through channels 9, however, is that the openings of the feed-through channels 9 lie on a smaller radius relative to the rotor shaft axis than that Areas of the feedthrough channels to which the heat is supplied, so that the Principle of the so-called thermosiphon is applicable. In this case, the Rotor shaft the difference between the pumping power for the cold cooling air and the Apply the turbine output of the warm cooling air.

It is also advantageous that the openings 11, 11 'largely on the same radius lie relative to the rotor shaft axis A; if this is not the case, the radial influences Pressure difference, i.e. the swirl in the cavity caused by the pressure difference Cooling effect.

In addition to the independently developing cooling flows that occur within a Implementation channel, comparatively in the manner of one of the aforementioned "Form thermosyphons', however, can also selectively flow cooling into the feedthrough channels 9 can be initiated. Since the openings 11 facing the rotor shaft side of the feed-through channels 9 due to the rotational movement of the rotor relative to the Cavity 5 located coolant can move through targeted training Opening geometry for each duct 9 the flow direction within of the channel.

In Fig. 1 b is the sectional view according to the section A entered in Fig. 1a - A is shown. The cross-sectional representation shown perpendicular to the axis of rotation in 1 b shows two adjacent feed-through channels 9, each on the rotor shaft side have facing openings 11, 11 'and of different sizes Inlet curves R and r have. The cooling medium in the cavity 5 flows relative to the rotor in the direction indicated by the large arrow. This Cross flow over the openings 11, 11 'is in the holes 11 with the larger ones Opening radii R generate a higher pressure than in the holes 11 'with smaller ones Opening radius r. This creates a radially outward cooling flow introduced into through ducts 9 adjoining the openings 11. This Flow continues through the circumferential groove 10 'and returns in the adjacent channels 9 with the smaller opening radii r back into the cavity 5.

As an alternative to the configuration of the openings of the feed-through channels shown in FIG. 1b, each have differently dimensioned opening radii R, r that alternate between adjacent passageways, it is also possible to design the opening area of a through-channel in such a way that an opening has two different radii R and r. So it is for the above described flow direction specification necessary, the opening areas two adjacent passageways, which are closest to each other form the same radii of curvature. (see Figure 1c)

So that the cooling system, as shown in Figs. 1b and 1c, work the number of feed-through channels 9 must assume a natural even number, so that an outflow channel is assigned to an inflow channel.

Alternatively or in addition to FIGS. 1 b and 1 c, opening contours shown, can create real scooping edges at the respective points of the openings of the through channels be provided. However, this is with an additional constructive Effort associated with the operation of the above "Thermosyphons" is not absolutely necessary.

The direct cooling of the blade feet of the moving blades by a targeted below the cooling medium introduced, preferably cooling air, is also the blade roots for reasons of possible contamination by dust particles within the Cooling system an advantage. For example, dust particles get through the feed-through channels in the circumferential grooves of the mounting rails, they can in principle also to blockages of the circumferential grooves and thus to a considerable one Reduce the cooling effect. On the one hand, one can counteract such contamination Provide so-called dust holes, such as those in cooled blades are used, on the other hand, it is easy for maintenance work Effort possible by removing the blades from the mounting rail to easily remove contaminants deposited in the circumferential grooves.

LIST OF REFERENCE NUMBERS

1

rotor shaft

2

blade

Third

vane

4th

cooling system

4a

feed channel

4b

RückführungManal

5 ·

cavity

6 ·

Surface of the rotor shaft

7 ·

blade

8th·

Umfängsnut

9, 9 '

Through channel

10

hollow channel

10 '

circumferential groove

11, 11 '

Openings in the duct

A

Rotor shaft axis

R, r

Large and small radius of curvature of the openings 11, 11 '

Claims (22)

1. Rotor of a fluid-flow machine, which has moving blades (2) and/or other parts in one or more rows on a surface (6) of its rotor shaft (1), which moving blades (2) and/or other parts project through the surface (6) into the rotor shaft (1) in each case via a root (7) for fastening (1) [sic], the rotor shaft (1), in at least one region below the surface (6) close to at least one root (7), having at least one enclosed cavity (5), the cavity (5), for cooling purposes, being connected via at least one feed-through passage (9) to that end of a root (7) which faces the rotor-shaft side, and a cooling system (4) by means of which the cavity (5) can be supplied with a cooling medium being provided, characterized in that at least two feed-through passages (9) are arranged adjacent to one another over the circumference of the rotor shaft (1), the cooling medium circulating, in a feed-through passage (9), from the cavity (5) radially outwards into a hollow passage (10) and the cooling medium circulating back, in the adjacent feed-through passage (9) in the circumferential direction, from the hollow passage (10) radially inwards into the cavity (5).
2. Rotor according to Claim 1, characterized in that cooling air is preferably provided as the cooling medium.
3. Rotor according to either of Claims 1 and 2, characterized in that the cavity (5) is at a distance from the ends of the rotor shaft (1).
4. Rotor according to one of Claims 1 to 3, characterized in that the feed-through passage (9) is arranged radially or obliquely radially to the rotor shaft (1).
5. Rotor according to one of Claims 1 to 4, characterized in that the root (7) sits in a circumferential slot (8) inside the rotor shaft (1), which circumferential slot (8) provides the hollow passage (10) radially below the inserted root (7), and this hollow passage (10) is connected to the at least two feed-through passages (9).
6. Rotor according to one of Claims 1 to 4, characterized in that the root (7) sits in an axial slot inside the rotor shaft (1), which axial slot runs axially or obliquely axially at the surface of the rotor shaft (1) and has the hollow passage (10) radially below the inserted root (7), and this hollow passage (10) is connected to the at least two feed-through passages (9).
7. Rotor according to Claim 5 or 6, characterized in that the circumferential slot and/or axial slot as well as the root have serrations for mutual fastening.
8. Rotor according to one of Claims 1 to 5, characterized in that a multiplicity of moving blades (2) or parts are arranged radially next to one another at the surface (6) of the rotor shaft (1), to the roots (7) of which moving blades (2) or parts a feed-through passage (9) is allocated in each case.
9. Rotor according to Claim 8, characterized in that a feed-through passage (9) has an opening (11, 11') to the cavity (5), the rounded inlet portion in the radial direction of which opening (11, 11') is in each case dimensioned in such a way that the openings (11, 11') of two directly adjacent feed-through passages (9) have different radii (R, r).
10. Rotor according to Claim 9, characterized in that the openings (11, 11') have a large (R) or a small (r) rounded inlet portion.
11. Rotor according to Claim 8, characterized in that the opening (11, 11') of a feed-through passage (9) has two rounded inlet portions (R, r) in the radial direction, designed to be of different sizes, and adjacent rounded inlet portions (R, r) between two feed-through passages (9) correspond.
12. Rotor according to one of Claims 1 to 11, characterized in that the hollow passages (10) under all roots made in a distributed manner around the rotor shaft (1) are connected to one another to form a circumferential passage (10').
13. Rotor according to Claim 12, characterized in that an even number of radial and/or obliquely radial feed-through passages (9) lead into a circumferential passage (10').
14. Rotor according to one of Claims 1 to 13, characterized in that the fluid-flow machine is a turbine, a compressor stage of a gas turbine or of a steam turbine.
15. Rotor according to one of Claims 1 to 14, characterized in that the rotor moves relative to a medium contained in the cavity (5).
16. Rotor according to one of Claims 1 to 15, characterized in that the root (7) of a moving blade (2) or of a part is arranged radially above the cavity (5).
17. Rotor according to one of Claims 1 to 16, characterized in that the part is a heat segment or a heat shield.
18. Rotor according to one of Claims 1 to 17, characterized in that the cooling system (4) has cooling passages (4a, 4b), which run in the rotor shaft (1) and can be supplied with cooling air.
19. Rotor according to one of Claims 1 to 18, characterized in that the cooling passages (4a, 4b) of the cooling system (4) impart a swirl, relative to the rotor, to the cooling medium in the cavity (5) in the circumferential direction of the rotor, in which case the relative swirl may flow with or against the direction of rotation of the rotor.
20. Rotor according to one of Claims 1 to 19, characterized in that one of the cooling passages (4a, 4b) has a return passage (4b) which discharges the heated cooling medium from the cavity (5) and leads out at the innermost radius of the cavity (5).
21. Rotor according to one of Claims 1 to 20, characterized in that the cooling passage (4b) which discharges the heated cooling medium from the cavity (5) is insulated with respect to the rotor material.
22. Rotor according to one of Claims 1 to 21, characterized in that the cavity (5) extends up to the rotor-shaft axis (A).

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