EP2123860B1 - Combined vortex reducer - Google Patents

Description

The invention relates to a vortex rectifier for guiding bleed air streams. Moreover, the invention relates to a method for guiding extraction air flows by means of the vortex rectifier.

In a gas turbine, bleed air streams are branched from the air flow in the compressor to cool or seal certain components. The bleed air streams are conveyed between two adjacent rotor disks of the compressor, e.g. in the sixth stage of the high-pressure compressor, for example, branched off through holes in one of the rotor discs of the compressor and flow through an intermediate disc chamber between the two rotor discs in the direction of the shaft.

In the inter-disk chamber, the extraction air flows form a free extraction air vortex, resulting in high pressure losses. In order to reduce the pressure losses, vortex rectifiers are used.

The bleed air streams, after passing through the inter-disk chamber, are directed along the shaft downstream into the area of the turbine to be there, e.g. to seal the spaces between the rotor disks of the turbine. Subsequently, the extraction air is passed into the gas stream.

The radial air extraction at very high rotor speeds and the subsequent deflection of the flow in the region of the shaft in the axial direction causes a not negligible pressure loss. In order to achieve the lowest possible pressure loss, vortex reducers (Vortex Reducer) are used in practice. These are in the simplest case straight, radially inwardly directed pipe systems in which the air is forced out.

The advantage of a vortex rectifier is that the air does not experience an increase in its peripheral speed when flowing through the intermediate disc chamber to the shaft center and thus does not form a free vortex. Thus, the concomitant pressure loss is lower than would be the case compared to a non-swirl reduced system.

From the EP 1 457 640 B1 a swirl rectifier is known, which is formed from an annular bearing leg on one of the adjacent rotor disks of the compressor, a separate carrier ring and a plurality of bleed air tubes. The carrier ring is fastened in the radially outer region to the adjacent rotor disks of the compressor. The bleed air tubes are arranged in openings on the circumference of the carrier ring and directed radially inwardly toward the shaft. The openings in the carrier ring adjoin hole passages in the annular bearing leg.

In the EP 1 564 373 B1 a swirl rectifier without support ring is described, in which the bleed air tubes are inserted directly into the hole passages of the annular bearing leg on one of the adjacent rotor disks of the compressor.

In the US Pat. No. 7,159,402 B2 discloses a vortexer with bleed air tubes wherein the bleed air streams be deflected at the exit from the bleed air tubes, wherein the radial bleed air flows to a total axial air flow.

However, these vortex rectifiers require much material because of the large number of bleed air tubes and consequently have a high weight. In addition, due to the high temperature and friction of the bleed air streams, these vortexers tend to wear on the bleed air tubes.

The US 4,919,590 describes a vortex reducer formed of vanes formed radially on one of the rotor disks forming the inter-disk chamber. There are thus circular segment-shaped channels between the blades, which guide the extraction air flows in the intermediate disc chamber.

In this vortexer, however, the bleed airflows are only partially conducted, i. there are still strong turbulences in the inter-disk chamber available. The pressure loss is therefore not sufficiently reduced.

The invention is therefore based on the object to provide a vortex rectifier, for which little material is needed and therefore has a low weight, at the same time directed extraction air flows are generated with low pressure losses.

This object is achieved with a vortex rectifier for guiding extraction air flows according to claim 1. Furthermore, the object with a method for guiding extraction air flows according to claim 9 solved. Advantageous embodiments of the invention are contained in the subclaims.

According to the invention, the solution of the problem in a vortex rectifier for guiding bleed air flows, which is arranged in an inter-disk chamber between two rotor disks of the compressor of a gas turbine with at least one shaft and at least one ring with circumferentially arranged first hole passages, second hole passages and extraction air tubes. Also, bleed air tubes are disposed only in the first hole passages with the bleed air tubes uniformly distributed around the circumference of the ring and the second hole passages being free of bleed air tubes, and first partial air flows through the first hole passages into the bleed air tubes and second partial air streams through the second hole passages into clearances are feasible between the bleed tubes.

This vortex rectifier thus has a combination of first hole passages with bleed air tubes and second hole passages without bleed air tubes. The combined vortex rectifier requires less material and thus has a lower weight than the prior art tube type vortex rectifiers. At the same time the formation of a free vortex is prevented in the intermediate disc chamber, whereby a swirl reduction is ensured. In addition, the vortex rectifier is less susceptible to wear than the vortex rectifier EP 1 457 640 B1 or EP 1 564 373 B1 because it has a lower number of bleed air tubes. In addition, the centrifugal forces acting on the ring are lower than in these two prior art embodiments.

Preferably, the first hole passages with bleed air tubes comprise one-third and the second hole passages two-thirds of the total number of hole passages. This selection causes a significant reduction in weight while sufficient swirl reduction. However, another ratio between first and second hole passages can be selected.

In a preferred embodiment, the bleed air tubes are arranged in a straight line radially. This allows a particularly low-loss radial flow of the bleed air through the vortex rectifier.

Alternatively, the bleed air tubes may be curved against the direction of rotation of the compressor. This causes the partial airflows in the circumferential direction to enter the shaft channel at an angle of, for example, 45 ° to the radius and not be braked by a radial flow against the shaft. The curvature against the direction of rotation of the compressor prevents the formation of swirl in the interstices of the vortex rectifier and in the wave channel.

In particular, the bleed air tubes have ribs which protrude into the spaces between the rotor discs. Through these ribs, the bleed air streams between the bleed air tubes can be further straightened.

In a further advantageous embodiment of the invention, the extraction air tubes are oval in cross-section. Due to the oval cross-section, the bleed air tubes fill the inter-plate chamber in the axial direction better. This prevents a portion of the bleed air from radially rotating past the bleed air tubes.

In addition, radial blades may be mounted on at least one of the two rotor disks, which project axially into the spaces between the extraction air tubes. Also by these blades, which can be used as an alternative to the above-mentioned ribs or in addition to these, the extraction air flows can be additionally performed.

Furthermore, at least one deflection device can be provided at the radially inner ends of the bleed air tubes and / or on the shaft of the gas turbine. The deflection device can reduce the turbulence in the exit of the extraction air flows from the vortex rectifier in the region of the shaft and thus further reduce the pressure loss.

Furthermore, the solution of the problem in a method for guiding extraction air flows by means of the vortex rectifier, wherein the bleed air flows which flow through the hole passages in the bleed air tubes, are guided to the shaft. The bleed air streams pass into first partial air streams and second partial air streams, wherein only the first partial air streams flow through the first hole passages into the bleed air tubes and the second partial air streams flow through the second hole passages into the interspaces between the bleed air tubes and are thereby guided to the shaft.

The combined use of bleed air tubes and free hole passages directs the bleed air streams to the shaft. On the one hand, the air undergoes a swirl reduction in the bleed air tubes, and on the other hand, the air flowing through the free hole passages also experiences a swirl reduction through the outside of the bleed air tubes. The bleed air tubes thus prevent formation of a free vortex in the intermediate disc chamber.

In an advantageous embodiment of the invention, the second partial air streams are additionally guided in the interstices between the bleed air tubes by means of the ribs on the bleed air tubes and / or by means of the blades. In this way, an additional swirl reduction in the partial air flow between the bleed air tubes is achieved.

Furthermore, the bleed air tubes can guide the first partial air streams and the second partial air streams in the radial direction from outside to inside. This causes a particularly low-loss flow through the vortex rectifier.

Alternatively, the bleed air tubes may carry the first partial air streams and the second partial air streams in the opposite direction to the direction of rotation of the compressor and at the same time to the shaft. As already described above, a fluidically favorable transition from the vortex rectifier to the shaft channel is achieved in this way.

In addition, the deflection device can deflect the emerging in the region of the shaft from the vortex rectifier first and second partial air flows and generate an axial total air flow from the first and second partial air streams. The flow is thus still reduced swirl, so that the turbulence at the transition from the vortex rectifier can be reduced to the wave channel.

Fig. 1

eine perspektivische Ansicht eines erfindungsgemäßen Wirbelgleichrichters,

Fig. 4

eine Draufsicht auf ein Segment des Wirbelgleichrichters,

Fig. 2

einen Radialschnitt durch einen Entnahmeluftkanal des Wirbelgleichrichters und

Fig. 3

einen Radialschnitt durch eine freie Lochpassage des Wirbelgleichrichters.

In the following an embodiment of the invention will be explained in more detail with reference to three figures. Show it:

Fig. 1

a perspective view of a vortex rectifier according to the invention,

Fig. 4

a plan view of a segment of the vortex rectifier,

Fig. 2

a radial section through a bleed air duct of the vortex rectifier and

Fig. 3

a radial section through a free hole passage of the vortex rectifier.

The Fig. 1 and 2 show a vortex rectifier 10 according to the invention. The vortex rectifier 10 comprises a carrier ring 11 with first hole passages 13, second hole passages 14 and extraction air tubes 15.

The ring formed as a carrier ring 11 has a flange 11 a, which is angled radially outward. The first and second hole passages 13 and 14 are arranged on the periphery of the carrier ring 11. In the first hole passages 13 a rectilinear extraction air tube 15 is arranged in each case. By contrast, the second hole passages 14 have no extraction air tubes 15. A first hole passage 13 with a discharge air tube 15 alternates in the circumferential direction with two hole passages 14 without extraction air tubes 15. Due to this combination of first hole passages 13 with extraction air tubes 15 and second hole passages 14 without extraction air tubes 15 the vortex rectifier 10 also referred to as a combined vortex rectifier.

The bleed tubes 15 each have a radially outer end 15a with which the bleed air tube 15 is attached to the carrier ring 11. In addition, the bleed air tubes 15 each have a radially inner end 15b which projects radially into the interior of the carrier ring 11. Between two adjacent evacuation air tubes 15 is ever a gap 16.

In Fig. 2 In addition to the segment of the vortex rectifier 10, a first partial air flow 22 and a second partial air flow 23 are shown as representative of the first and second partial air flows flowing through the vortex rectifier 10. The first partial air flows are caused by the entry of the in Fig. 2 Discharge air streams, not shown, into the first hole passages 13. The second partial air streams are created by the entry of the in Fig. 2 Not shown, extraction air flows into the second hole passages 14. By way of example, a respective extraction air flow 21 in the Fig. 3 and 4 shown.

The first partial air flow 22 flows radially from outside to inside through the first hole passage 13 and the discharge air tube 15 toward the shaft. The second partial air flow 23 flows radially from outside to inside through the second hole passage 14 and the intermediate space 16 between two discharge air tubes 15 toward the shaft. The arrow 25 indicates the direction of rotation of the compressor, not shown, and thus of the vortex rectifier 10.

In the Fig. 3 and 4 is the vortex rectifier 10 in each case in the installed position together with a first rotor disk, a second rotor disk 2 and a screw connection 12 shown.

The first rotor disk 1 is constructed concentrically to the center line 5 and has a radially outer region 1a, on which the screw connection 12 is located.

The second rotor disk 2 is also constructed concentrically to the center line 5 and has a bearing leg 4, which is of annular construction and protrudes slightly radially inwardly in the direction of the first rotor disk 1 from the radially outer region 2a of the second rotor disk 2. The bearing leg 4 is provided with a radially inwardly directed flange 4a. In addition, the bearing leg 4 on its circumference uniformly distributed openings 4b. The flange 4 a of the bearing leg 4 is fastened by means of the screw connection 12 at the radially outer region 1 a of the first rotor disk 1.

The first rotor disk 1 and the second rotor disk 2 are arranged parallel to each other in the compressor, not shown, and belong to the high-pressure compressor. Between the first rotor disk 1 and the second rotor disk 2 there is an intermediate disk chamber 3 with a radially outer part 3a and a radially inner part 3b. The radially outer part 3a of the intermediate disc chamber 3 is located between the carrier ring 11 of the vortex rectifier 10, the second rotor disc 2, the bearing leg 4 and the screw connection 12. The radially inner part 3b of the intermediate disc chamber 3 is through the support ring 11, the first rotor disc 1 and the second rotor disc 2 limited.

In the inter-disk chamber 3, the vortex rectifier 10 is arranged concentrically to the center line 5 and parallel to the first and second rotor disks 1 and 2. The radially outwardly angled flange 11a of the carrier ring 11 of the vortex rectifier 10 is located between the radially inwardly angled flange 4a of the bearing leg 4 of the second rotor disk 2 and the outer region 1a of the first rotor disk 1 and is therefore also by means of the screw 12 at the first Rotor disc 1 attached. The vortex rectifier 10 is aligned in the intermediate disc chamber 3 so that the first and second hole passages 13 and 14 radially substantially to the openings 4b in the bearing leg 4 of the second rotor disc 2 show.

As an alternative to the arrangement shown, in which the withdrawal air tubes 15 are arranged in the first hole passages 13 of the carrier ring 11, the removal air tubes 15 can also be inserted directly into openings 4b of the bearing leg 4. In this case, no separate carrier ring 11 is required.

Instead of the radially arranged bleed air tubes 15 can be provided in the circumferential direction opposite to the direction of rotation 25 of the compressor bleed air tubes that lead the partial air streams 22 and 23 against the direction of rotation 25 of the compressor, not shown.

In Fig. 3 is the course of the extraction air through a first hole passage 13 and a discharge air tube 15 of the vortex rectifier 10 representative of other extraction air streams, not shown, as the first partial air flows through the first hole passages 13 and bleed air tubes 15 of the vortex rectifier 10 flow, shown.

The exemplified removal air flow 21 is first branched off from the compressor air flow 20 and passed through the openings 4b of the bearing leg 4 in the radially outer part 3a of the intermediate disc chamber 3. From there, a partial air flow 22 flows from the radially outer portion 3a of the intermediate disc chamber 3 through the first hole passages 13 of the vortex rectifier 10 from the radially outer end 15a of the withdrawal air tube 15 through the withdrawal air tube 15 to the radially inner end 15b of the withdrawal air tube 15. At the radially inner End 15b of the sampling tube 15 exits the partial air flow from the vortex rectifier 10 and merges with the other not shown first and second partial air flows to a total air flow 24, which in the axial direction along a shaft, not shown, which runs along the center line 5 continues to flow.

In Fig. 4 the course of the bleed air through a second hole passage 14 of the vortex rectifier 10 is representative of other not shown bleed air streams, which flow as second partial air streams through the second hole passages 14 of the vortex rectifier 10, shown.

The exemplified removal air flow 21 is first branched off from the compressor air flow 20 and passed through the openings 4b of the bearing leg 4 in the radially outer part 3a of the intermediate disc chamber 3. From there, flows a partial air flow 23 from the radially outer portion 3a of the intermediate disc chamber 3 through the second hole passages 14 and between the extraction air tubes 15, ie the partial air flow 23 flows substantially radially from outside to inside through the radially inner part 3b of the intermediate disc chamber 3 to the shaft.

Between the radially inner ends 15b of the adjacent intake air tubes 15, the partial air flow 23 exits from the vortex rectifier 10 and merges with the other, not shown, first and second partial air flows to a total air flow 24, which continues to flow in the axial direction along a shaft, not shown.

In operation, so in the Fig. 2 and 3 shown by way of example partial air flow 22 and the remaining through the first hole passages 13 flowing, not shown, the first partial air flows through the discharge air tubes 15 rectilinearly guided radially from outside to inside. As it flows through the extraction air tube 15, the partial air flow 22 cools down.

The in the Fig. 2 and 4 By contrast, partial air flow 23 and the other second partial air flows flowing through the second hole passages 14, as shown by way of example, are guided from the outside inwards in the radial direction through the intermediate spaces 16 between the adjacent extraction air tubes 15, as in FIG Fig. 2 becomes particularly clear.

By the extraction air tubes 15, the formation of a free vortex is prevented in the intermediate disc chamber 3 in the direction of rotation 25 of the compressor, not shown, and thus significantly reduces the pressure loss in the extraction air. At the same time, little material is required for the vortex rectifier 10. The ratio of free second hole passages 14 to the first hole passages 13 connected to the extraction air tubes 15 should be as large as possible, eg 2: 1. In addition, the entire vortex rectifier should have the largest possible diameter, so that the first and second partial air streams 22 and 23 are guided over as long as possible.

LIST OF REFERENCE NUMBERS

1

First rotor disk

1a

Radially outer area

2

Second rotor disk

2a

Radially outer area

3

Disk interspace

3a

Radial outer part

3b

Radially inner part

4

bearing legs

4a

flange

4b

opening

5

center line

10

Vortex reducer

11

support ring

11a

flange

12

screw connection

13

First hole passage

14

Second hole passage

15

Removal trachea

15a

Radially outer end

15b

Radially inner end

16

gap

20

Compressor air flow

21

Extraction airflow

22

First partial air flow

23

Second partial air flow

24

Total airflow

25

direction of rotation

Claims (13)

1. Vortex reducer (10) for the guidance of bleed airflows (21), which is arranged in an inter-disk chamber (3) between two rotor disks (1, 2) of the compressor of a gas turbine and includes at least one ring (11) with circumferentially disposed first hole passages (13), second hole passages (14) and bleed air tubes (15), characterized in that bleed air tubes (15) are arranged only in the first hole passages (13), where the bleed air tubes (15) are evenly distributed on the circumference of the ring (11), and the second hole passages (14) are devoid of bleed air tubes (15), and where first partial airflows (22) can be guided through the first hole passages (13) into the bleed air tubes (15) and second partial airflows (23) through the second hole passages (14) into interspaces (16) between the bleed air tubes (15).
2. Vortex reducer (10) in accordance with Claim 1, characterized in that the first hole passages (13) with bleed air tubes (15) include one third and the second hole passages (14) two thirds of the total number of hole passages (13, 14).
3. Vortex reducer (10) in accordance with one of the Claims 1 or 2, characterized in that the bleed air tubes (15) are rectilinearly arranged in the radial direction.
4. Vortex reducer (10) in accordance with one of the Claims 1 to 3, characterized in that the bleed air tubes (15) are curved against the direction of rotation (25) of the compressor.
5. Vortex reducer (10) in accordance with one of the Claims 1 to 4, characterized in that the bleed air tubes (15) are provided with fins protruding into the interspaces (16) between the rotor disks (1, 2).
6. Vortex reducer (10) in accordance with one of the Claims 1 to 5, characterized in that the bleed air tubes (15) are provided with an oval cross-section.
7. Vortex reducer (10) in accordance with one of the Claims 1 to 6, characterized in that radial blades, which axially protrude into the interspaces (16) between the bleed air tubes (15), are provided on at least one of the two rotor disks (1, 2).
8. Vortex reducer (10) in accordance with one of the Claims 1 to 7, characterized in that at least one deflector is provided on the radially inner ends (15b) of the bleed air tubes (15) and/or on the shaft of the gas turbine.
9. Method for the guidance of bleed airflows by means of the vortex reducer (10) in accordance with one of the Claims 1 to 8, where the bleed airflows (21) passing through the hole passages into the bleed air tubes (15) are guided towards the shaft, characterized in that the bleed airflows (21) transit into first partial airflows (22) and second partial airflows (23), where only the first partial airflows (22) pass through the first hole passages (13) into the bleed air tubes (15), and the second partial airflows (23) through the second hole passages (14) into the interspaces (16) between the bleed air tubes (15), thereby being guided towards the shaft.
10. Method in accordance with Claim 9, characterized in that the second partial airflows (23) in the interspaces (16) between the bleed air tubes (15) are additionally guided by means of the fins on the bleed air tubes (15) and/ or by means of the blades.
11. Method in accordance with Claim 9 or 10, characterized in that the bleed air tubes (15) lead the first partial airflows (22) and the second partial airflows (23) in the radial direction from the outer to the inner side.
12. Method in accordance with one of the Claims 9 to 11, characterized in that the bleed air tubes (15) lead the first partial airflows (22) and the second partial airflows (23) in the direction opposite to the direction of rotation (25) of the compressor and also towards the shaft.
13. Method in accordance with one of the Claims 9 to 12, characterized in that the deflector deflects the first and second partial airflows (22, 23) issuing from the vortex reducer (10) in the area of the shaft and produces an axial total airflow (24) from the first and second partial airflows (22, 23).

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