DE29701592U1 - Thermal fluid machine - Google Patents

Description

5.2.96 96/008

Thermal flow machine

Technical area

The invention relates to a thermal turbomachine with a device for preventing vibrations in its rotor blades.

State of the art

Damper wires are often used to dampen the vibrations of rotor blades that are susceptible to vibration. Such a damper wire is loosely guided in appropriately arranged recesses of several adjacent rotor blades and connects them to form a blade package. When the rotor blades are in operation, the damper wire rests radially outwards in the recesses under the effect of centrifugal force. In this way, it dampens the vibrations of the rotor blades of its blade package that are aligned against one another, unevenly or out of phase.

The blade packs equipped with the previously known damper wires are open in the circumferential direction at the mounting point of the damper wire. A separating surface is formed between the two ends of the damper wire and is arranged in one of the blade spaces of the respective blade pack. As a result, the rotor blades adjacent to the separating surface, i.e. the edge blades of a pack, are not sufficiently supported. However, this leads to insufficient damping of the vibrations of these edge blades during the rotation of the turbomachine. Blade vibration fractures are therefore often recorded on the edge blades of the pack.

In order to achieve closed damper wire packages, so-called shrouds are often used today. Such shrouds are well suited for use in power plant construction, i.e. in gas and steam turbines. However, turbochargers have higher speeds and stronger centrifugal loads. The associated high tangential stresses are difficult to control and can lead to the destruction of the shrouds. This means that the damping of the associated blade package is no longer guaranteed. Due to these relationships, shrouds are not used in turbocharger turbines.

Description of the invention

The invention attempts to avoid all of these disadvantages. Its aim is to create a thermal turbomachine with at least one closed blade package whose damping element does not exhibit any tangential stresses.

an improved device, also suitable for high speeds, to prevent vibrations on their rotor blades.

According to the invention, this is achieved in that, in a device according to the preamble of claim 1, the wire ends of the damper wire are arranged to overlap one another and an overlap region is formed which is arranged at least in the region of the recess of at least one rotor blade.

This design and arrangement of the damper wire results in a closed blade package in which the blades adjacent to the wire ends are also adequately supported. Because the overlapping wire ends can be moved in the circumferential direction, no tangential stresses can build up.

As a result, the risk of blade vibration fractures is reduced and the availability of the thermal turbomachine is increased.

For this purpose, the damper wire in a first embodiment of the invention is designed to be split at least in the overlapping area of the wire ends, in the circumferential direction of the blade package. Both wire ends of the damper wire are recessed in this area in a corresponding manner.

It is also advantageous if the overlap area of the wire ends extends over several blades and their corresponding blade gaps. With such a design, the supporting effect of the damper wire in the overlap area is improved. An arrangement of the two wire ends of the damper wire offset by 180" from each other proves to be particularly advantageous because this prevents imbalance in the blade package.

In a second embodiment of the invention, the damper wire is completely divided in the circumferential direction of the blade package. It consists of a first and a second partial wire. Each of the partial wires has a first and a second wire end. The first wire end of each partial wire is arranged to overlap the second wire end of the other partial wire.

The overlap area extends over several blades and their corresponding gaps between the blades, whereby the supporting effect of the damper wire in the overlap area is improved. It is particularly advantageous for the wire ends of the first part of the wire to be arranged offset by 180° from the wire ends of the second part of the wire. In this way, a uniform mass distribution is achieved over the circumference of the blade package, so that no imbalances can arise. The arrangement proves to be advantageous

of the wire ends in the area of the recesses, because this prevents uncontrolled bending of the blade ends.

Finally, the wire ends are bent at right angles to the circumferential direction of the blade package. This prevents the damper wire from slipping in the circumferential direction of the blade package.

Short description of the drawing

The drawing shows an embodiment of the invention based on a turbine blade of an exhaust gas turbocharger provided with a damper wire.

Show it:

Fig. 1 shows a partial cross-section of the turbine blade with the damper wire designed according to the invention;

Fig. 2 shows a damper wire hole remaining cross-section, in a first embodiment, shown enlarged;

Fig. 3 is a representation corresponding to Fig. 2, but in a second embodiment.

Only the elements essential for understanding the invention are shown. Not shown are, for example, all other components of the exhaust turbine, the housing and the entire compressor side of the exhaust turbocharger.

Way to implement the invention

The exhaust turbine of an exhaust turbocharger has a row of turbine blades 1, which are arranged on a shaft 3 by means of a common turbine disk 2 (Fig. 1).

All turbine blades 1 are connected to a blade package 5 by means of a damper wire 4 (Fig. 2). A recess 6 is arranged in each turbine blade 1 to accommodate the damper wire 4.

A blade gap 7 is formed between the adjacent blades 1. The damper wire 4 has a first and a second wire end 8, 9. Both wire ends 8, 9 are arranged so as to overlap one another (Fig. 1). This forms an overlapping area 10 which extends partially over two adjacent blade gaps 7 and the recess 6 of the turbine blade 1 arranged between them. In the overlapping area 10 of the wire ends 8, 9, the damper wire 4 is divided in the circumferential direction of the blade package 5. In a first embodiment, the wire ends 8, 9 of the damper wire 4 are recessed so as to correspond with one another (Fig. 2).

Due to this design, the damper wire 4 extends around the entire circumference of the recesses 6 of the turbine blades 1, so that a closed blade package 5 is created. This means that when the exhaust gas turbocharger is operating, the exhaust gas turbine blades 1 arranged in the area of the wire ends 8, 9 are also sufficiently supported, which reduces the frequency of blade vibration fractures.

In a second embodiment, the damper wire 4 is completely divided in the circumferential direction. It consists of a first and a second partial wire 11, 12 (Fig. 1). Both partial wires 11, 12 each have a first wire end 13, 15 and a second wire end 14, 16. The first wire end

13 of the first partial wire 11 overlaps the second wire end 16 of the second partial wire 12, while the second wire end

14 of the first partial wire 11 is overlapped by the first wire end 15 of the second partial wire 12. In this embodiment, the wire ends 13, 14 of the first partial wire 11

96/008 6

and the wire ends 15, 16 of the second wire section 12 are arranged in an adjacent blade gap 7 (Fig. 3). Of course, several rotor blades 1 with the corresponding blade gaps 7 can also be located between the wire ends 13, 14 or 15, 16 of the first or second wire section 11, 12. An arrangement of the wire ends 13, 14 of the first wire section 11 offset by 180° from the wire ends 15, 16 of the second wire section 12 on the circumference of the recesses 6 (not shown) is particularly favorable. This avoids imbalances in the blade package 5.

In order to prevent the wire ends 8, 9 or 13, 14 and 15, 16 of the damper wire 4 from moving in the circumferential direction of the blade package 5 in both embodiments, they can be bent at right angles to the circumferential direction after they have been installed (also not shown).

Of course, the application of the solution according to the invention is not limited to the exhaust turbine of an exhaust gas turbocharger. The rotor blades of a gas turbine, a steam turbine or a compressor can also be protected against vibration fractures.

List of reference symbols

1 blade, turbine blade

2 Turbine disc

3 Wave

4 Damper wire

5 Shovel Pack

6 Recess

7 Blade space

8 Wire end, first

9 Wire end, second

10 Overlap area

11 Part wire, first

12 Part wire, second

13 Wire end of 11, first

14 Wire end of 11, second

15 Wire end of 12, first

16 Wire end of 12, second

Claims (10)

• · · · &PSgr; 9 * ♦♦· · 96/008SF 8 Protection claims Thermal turbomachine, in particular turbocharger, with at least one row of rotor blades (1) arranged on a common shaft (3) and each provided with a recess (6) for receiving at least one damper wire (4), which are connected by means of the damper wire or the damper wires (4) to form at least one blade package (5), wherein a blade gap (7) is formed between each two adjacent rotor blades (1) and each damper wire (4) has a first and a second wire end (8, 9), characterized in that the wire ends (8, 9) are arranged overlapping one another and an overlap region (10) is formed, which is arranged at least in the region of the recess (6) of at least one rotor blade (1). 2. Thermal turbomachine according to claim 1, characterized in that the damper wire (4) is divided in the circumferential direction of the blade package (5), at least in the overlap region (10) of the wire ends (8, 9). 3. Thermal flow machine according to claim 1 or 2, characterized in that both wire ends (8, 9) of the damper wire (4) are recessed in a corresponding manner in the overlapping region (10). 4. Thermal turbomachine according to claim 3, characterized in that the overlap region (10) extends over several rotor blades (1) and their blade spaces (7). 96/008 9 5. Thermal turbomachine according to claim 4, characterized in that the first wire end (8) of the damper wire (4) is arranged in the circumferential direction of the blade package (5) offset by 180° from the second wire end (9). 6. Thermal turbomachine according to claim 1 or 2 , characterized in that the damper wire (4) is completely divided in the circumferential direction of the blade package (5), consists of a first and a second partial wire (11, 12), each of the partial wires (11, 12) has a first wire end (13, 15) and a second wire end (14, 16) and the first wire end (13, 15) of each partial wire (11, 12) is arranged to overlap the second wire end (16, 14) of the other partial wire (12, 11). 7. Thermal turbomachine according to claim 6, characterized in that the overlap region (10) extends over several rotor blades (1) and their blade spaces (7). 8. Thermal turbomachine according to claim 7, characterized in that the wire ends (13, 14) of the first partial wire (11) are arranged in the circumferential direction of the blade package (5) offset by 180° from the wire ends (15, 16) of the second partial wire (12). 9. Thermal flow machine according to one of claims 6 to 8, characterized in that the wire ends (13, 96/008 10 14, 15, 16) are each arranged in the area of the recesses (6). 10. Thermal turbomachine according to one of claims 1 to 8, characterized in that the wire ends (8, 9, 13, 14, 15, 16) are perpendicular to the circumferential direction of the
Blade package (5) are cranked.