EP2696042B1 - Fluid flow engine with at least one guide blade assembly - Google Patents

Description

The invention relates to a turbomachine, in particular an axial compressor, with at least one vane ring and a method for increasing the stability of the flow in a turbomachine.

In turbomachinery, adjustable vanes are often present, especially at the front stages of compressors. Depending on the operating state of the turbomachine, the inflow angles to the following blades are thus set and the energy conversion of the stage formed by the vanes and the rotor blades is controlled. When the vanes are adjusted, the flow angle changes over the entire channel height. However, when the operating state changes, the distribution of the local mass flow changes along the channel height. As a result, the stability of the flow in the turbomachine can be reduced and the efficiency can be reduced.

To increase the stability of the flow in a turbomachine, various measures are known. For example, the EP 0 745 755 A1 a specially shaped guide vane for a compressor of a gas turbine. The vane has an angled towards the blade root rear edge. The use of such vanes improves the stability of the flow and thus increases the compressor pumping limit. The disadvantage here is that the geometry of the vanes is adapted to a particular operating condition at a deviation from the operating condition no improved flow is more guaranteed.

The DE 10 2009 023 100 A1 describes a vane device with vanes arranged downstream of each other in the flow direction, wherein the trailing edges of the upstream vanes are shaped differently than the leading edges of the downstream vane, resulting in an uneven distance along the vane edges. Also by this arrangement, the flow in the turbomachine is to be stabilized. The arrangement also has the Disadvantage on that the geometry of the blades is adapted to a specific operating condition.

In the US4995786A there is shown a turbomachine having at least one vane ring including at least one row of adjustable vanes, each vane having a taper in a side view of the vane with respect to its airfoil in the direction of its longitudinal axis.

The WO 2007/042522 A1 describes a blade for a turbomachine in which the chord length is uneven along the blade length. This bucket minimizes blade lattice losses and is also designed for a specific operating range.

The invention is therefore based on the object to provide a turbomachine in which the stability of the flow improves and the operating range is extended.

This object is achieved with a turbomachine according to claim 1. Furthermore, the object is achieved with a method for increasing the stability of the flow in a turbomachine according to claim 15. Advantageous embodiments of the invention are contained in the subclaims.

According to the invention, the object is achieved in a turbomachine, in particular an axial compressor, with at least one vane ring comprising at least one row of adjustable vanes, wherein each vane in a side view of the vane with respect to its blade in the direction of its longitudinal axis has a taper. Each row of vanes includes first vanes and second vanes, wherein in a common side view of a first vane and a second vane, each first vane has a taper in a longitudinal direction along its airfoil and every other vane has a taper in an opposite direction.

The common side view is created by a juxtaposition of a loose first vane and a loose second vane. The common side view is not the view of a first vane and a second vane in their installed position.

The taper of each vane affects each associated airfoil. The counter-tapering of the vanes causes the flow to be more deflected in the unrestrained areas than in the tapered areas. This stabilizes the flow. A preferred field of application are axial compressors.

In a particular embodiment of the invention, at least a first vane and at least one second vane, preferably a total of two or three vanes, form a unit, and a plurality of these units are uniformly distributed in the circumferential direction of the vane ring, the distances between adjacent vanes different or equal are big.

Through various types of groupings of the first and second vanes, various evenly distributed or regularly bundled flow guides can be achieved.

In a further possible embodiment, the second guide vanes are arranged opposite the first guide vanes of the same row in the axial direction of the turbomachine in the same position or offset from one another. At the same position results in a compact design. By an offset arrangement, the flow guidance can be extended in the axial direction of the turbomachine.

In addition, in the common side view, the first guide vanes and the two guide vanes may have a covering region, wherein the covering region has a straight, oblique or curved course in the axial direction of the turbomachine. The overlap area allows in the radial direction of the turbomachine a flowing transition between the inner and outer flow guide in the channels between two adjacent vanes.

Additionally, the coverage area may range from 30% to 70% of a channel height defined by a length of the airfoil of each first vane and each second vane. This area gives the best results.

In a first embodiment, the taper of each first vane at the trailing edge of the respective first vane and the taper of each second vane at the trailing edge of the respective second vane are formed.

In a second embodiment, the taper of each first vane at the leading edge of the respective first vane and the taper of each second vane at the leading edge of the respective second vane are formed.

In a third embodiment, the taper of each first vane at the trailing edge of the respective first vane and the taper of each second vane at the leading edge of the respective second vane are formed.

In a fourth embodiment, the taper of each first vane at the trailing edge and the leading edge of the respective first vane and the taper of each second vane are also formed at the trailing edge and the leading edge of the respective second vane.

By virtue of the four different embodiments, different channel lengths and channel progressions between two adjacent guide vanes can be achieved in each case.

In particular, the taper can each be formed by a single or double curvature or the taper can be formed in each case by a gradation with at least two step transitions, each step transition is edged or rounded. A curvature allows a flowing deflection of the flow, while a gradation is easier to produce.

Specifically, the taper of each first vane may be 30% to 70% of the maximum width of each second vane, or the taper of each second vane may be 30% to 70% of the maximum width of each first vane. This area gives the best results.

In addition, the first vanes and the second vanes may each have different curvatures of the blade skeleton lines and / or the different profiles in the same position along the longitudinal axis. This allows a further, more detailed adaptation of the channels to the local flow.

In particular, in the radial direction of the turbomachine, the first guide vanes and the second guide vanes may each have different curvatures of the skeleton lines and / or different profiles in an outer region and an inner region.

This allows even more specific adaptation to the local flow in the channels. The overlap area ensures a smooth transition between the areas lying in the radial direction of the turbomachine outside and inside.

In a further embodiment, the first vanes and the second vanes are each rotatable about their longitudinal axis, wherein the first vanes and the second vanes are coupled or independently rotatable. As a result, the guide vane grille can be adapted to the operating state. The separate adjustment of the first and second vanes allows even more specific adaptation of the ducts.

Furthermore, the solution of the object in a method for increasing the stability of the flow in a turbomachine. In the radial direction of the turbomachine, each internally-tapered vane deflects the flow outwardly and each outwardly-tapered vane deflects the flow internally. The increased stability of the flow prevents compressor pumping and allows a larger operating range of the turbomachine.

Fig. 1

eine gemeinsame Seitenansicht einer ersten Leitschaufel und einer zweiten Leitschaufel einer erfindungsgemäßen Strömungsmaschine gemäß einem ersten Ausführungsbeispiel,

Fig. 2

eine gemeinsame Seitenansicht einer ersten Leitschaufel und einer zweiten Leitschaufel einer erfindungsgemäßen Strömungsmaschine gemäß einem zweiten Ausführungsbeispiel,

Fig. 3

eine gemeinsame Seitenansicht einer ersten Leitschaufel und einer zweiten Leitschaufel einer erfindungsgemäßen Strömungsmaschine gemäß einem dritten Ausführungsbeispiel,

Fig. 4

eine gemeinsame Seitenansicht einer ersten Leitschaufel und einer zweiten Leitschaufel einer erfindungsgemäßen Strömungsmaschine gemäß einer Variante zum dritten Ausführungsbeispiel,

Fig. 5

eine gemeinsame Seitenansicht einer ersten Leitschaufel und einer zweiten Leitschaufel einer erfindungsgemäßen Strömungsmaschine gemäß einem vierten Ausführungsbeispiel,

Fig. 6 a bis c

drei schematisch dargestellte Varianten einer Vorderkante oder einer Hinterkante einer Leitschaufel einer erfindungsgemäßen Strömungsmaschine,

Fig. 7

eine Einheit aus ersten und zweiten Leitschaufeln einer erfindungsgemäßen Strömungsmaschine in einem ersten Ausführungsbeispiel,

Fig. 8

eine Einheit aus ersten und zweiten Leitschaufeln einer erfindungsgemäßen Strömungsmaschine in einem zweiten Ausführungsbeispiel,

Fig. 9

eine Einheit aus ersten und zweiten Leitschaufeln einer erfindungsgemäßen Strömungsmaschine in einem dritten Ausführungsbeispiel,

Fig. 10

eine Einheit aus ersten und zweiten Leitschaufeln einer erfindungsgemäßen Strömungsmaschine in einem vierten Ausführungsbeispiel,

Fig. 11

eine Einheit aus ersten und zweiten Leitschaufeln einer erfindungsgemäßen Strömungsmaschine in einem fünften Ausführungsbeispiel,

Fig. 12

erste und zweite Leitschaufeln gemäß den Fig. 1, 6c und 7 in einer erfindungsgemäßen Strömungsmaschine,

Fig. 13

erste und zweite Leitschaufeln gemäß den Fig. 4, 6c und 7 in einer erfindungsgemäßen Strömungsmaschine und

Fig. 14

erste und zweite Leitschaufeln gemäß den Fig. 4, 6c und 8 in einer erfindungsgemäßen Strömungsmaschine.

In the following, several embodiments of the invention will be explained in more detail with reference to 12 figures. Show it:

Fig. 1

a common side view of a first vane and a second vane of a turbomachine according to the invention according to a first embodiment,

Fig. 2

a common side view of a first vane and a second vane of a turbomachine according to the invention according to a second embodiment,

Fig. 3

a common side view of a first vane and a second vane of a turbomachine according to the invention according to a third embodiment,

Fig. 4

a common side view of a first vane and a second vane of a turbomachine according to the invention according to a variant of the third embodiment,

Fig. 5

a common side view of a first vane and a second vane of a turbomachine according to the invention according to a fourth embodiment,

Fig. 6 a to c

three schematically illustrated variants of a leading edge or a trailing edge of a guide vane of a turbomachine according to the invention,

Fig. 7

a unit of first and second guide vanes of a turbomachine according to the invention in a first embodiment,

Fig. 8

a unit of first and second guide vanes of a turbomachine according to the invention in a second embodiment,

Fig. 9

a unit of first and second guide vanes of a turbomachine according to the invention in a third embodiment,

Fig. 10

a unit of first and second guide vanes of a turbomachine according to the invention in a fourth embodiment,

Fig. 11

a unit of first and second guide vanes of a turbomachine according to the invention in a fifth embodiment,

Fig. 12

first and second vanes according to Fig. 1 . 6c and 7 in a turbomachine according to the invention,

Fig. 13

first and second vanes according to Fig. 4 . 6c and 7 in a turbomachine according to the invention and

Fig. 14

first and second vanes according to Fig. 4 . 6c and 8th in a turbomachine according to the invention.

The Fig. 1 to 5 each show a schematic side view in common of a first vane 1 and a second vane 2 of a vane ring, not shown, of a turbomachine also not shown. In the Fig. 1 to 5 For example, the blade roots and the blade heads of the first vanes 1 and the second vanes 2 are not shown, so that the illustration refers to the airfoils.

The first vane 1 is shown in each case with a solid line. Each first vane 1 has a leading edge 1a, a trailing edge 1b, and a taper 1c.

The second vane 2 is shown in each case with a dashed line. Each second vane 2 has a leading edge 2a, a trailing edge 2b, and a taper 2c.

In the common side views, the first vanes 1 and the second vanes 2 have a common longitudinal axis 3 which is at the same time an axis of rotation. The longitudinal axes or axes of rotation of the first guide vanes 1 and the second guide vanes 2 can also be located in different positions in the axial direction of the turbomachine.

The first vanes 1 and second vanes 2 illustrated with respect to the airfoils define a channel height 4 having an inner portion 4a and an outer portion 4b in the radial direction of the turbomachine, not shown. Between the inner area 4a and the outer area 4b there is a covering area 4c.

In Fig. 1 is the taper 1c of the first vane 1 at the trailing edge 1b in the outer region 4b. The taper 2c of the second vane 2 is located at the trailing edge 2b in the inner region 4a. The covering area 4c has a straight course.

In Fig. 2 is the taper 1c of the first vane 1 at the front edge 1a in the inner region 4a. The taper 2c of the second vane 2 is located at the leading edge 2a in the outer region 4b. The covering area 4c has a straight course.

In Fig. 3 is the taper 1c of the first vane 1 at the trailing edge 1b in the inner region 4a. The taper 2c of the second vane 2 is located at the leading edge 2a in the outer region 4b. The covering area 4c has a straight course.

In Fig. 4 is the taper 1c of the first vane 1 at the trailing edge 1b in the outer region 4b. The taper 2c of the second vane 2 is located at the leading edge 2a in the inner region 4a. The covering area 4c has a straight course.

In Fig. 5 is the taper 1c of the first vane 1 at the leading edge 1a and at the trailing edge 1 b in the inner region 4a. The taper 2c of the second vane 2 is located at the leading edge 2a and at the trailing edge 2b in the outer region 4b. The covering area 4c has a curved course.

Thus, when the taper 1c of each first vane 1 is in the inner region 4a, the taper 2c of each second vane 2 is always in the outer region 4b and vice versa.

In operation, the flow at the taper 1c of each first vane 1 and at the taper 2c of each second vane 2 is locally less deflected than where there is no taper 1c on each first vane 1 and no taper 2c on each second vane 2.

In the Fig. 6a to c For example, three different examples of a leading edge 1a, 2a or a trailing edge 1b, 2b of a first vane 1 and a second vane 2 are shown in the overlapping area 4c.

In Fig. 6a The front edge 1a, 2a or the trailing edge 1b, 2b has two step transitions 5. The step transitions 5 are formed at right angles.

In Fig. 6b The front edge 1a, 2a or the trailing edge 1b, 2b has two step transitions 5. Between the step transitions 5 is a slope. 6

In Fig. 6c the leading edge 1a, 2a or the trailing edge 1b, 2b has a double curvature 7.

In the Fig. 7 to 9 three different schematic arrangements of first vanes 1 and second vanes 2 are shown in a row of a vane ring, not shown here. The arrangement is formed in each case from units 8 in which a specific combination of first guide vanes 1 and second guide vanes 2 is fixed. The units 8 are arranged uniformly along the entire inner periphery of the turbomachine, not shown.

In Fig. 7 The unit 8 comprises alternately arranged first guide vanes 1 and second guide vanes 2, which occupy the same position in the axial direction of the turbomachine, not shown.

In Fig. 8 The unit 8 comprises alternately arranged first guide vanes 1 and second guide vanes 2, which are arranged offset in the axial direction of the turbomachine, not shown.

In Fig. 9 The unit 8 comprises two adjacent guide vanes 1 and a second guide blade 2, which are arranged offset in the axial direction of the turbomachine, not shown. Likewise, further combination of first guide vanes 1 with second guide vanes 2 in the ratio of, for example, 3: 1 or 1: 1 is possible. However, a ratio of 2: 1 is preferred.

As in Fig. 10 sketched, is also a unit 8 with a "mirrored" combination possible. So is for example in FIG. 10 a combination of a first vane 1 with two second vanes 2 shown. Likewise, combination of first guide vanes 1 with second guide vanes 2 in the ratio of, for example, 1: 3 is possible.

In FIG. 11 another unit 8 is shown. In this embodiment, there is no axial overlap between the first blades 1 and the second blades 2.

The Fig. 12 to 14 In each case, a perspective view of an outwardly open guide vane ring 9 of the turbomachine, not shown, with first guide vanes 1 and second guide vanes 2 is shown.

In Fig. 12 The first vanes 1 and the second vanes 2 correspond to the Fig. 1 . 6c and 7 ,

In Fig. 13 The first vanes 1 and the second vanes 2 correspond to the Fig. 4 . 6c and 7 ,

In Fig. 14 The first vanes 1 and the second vanes 2 correspond to the Fig. 4 . 6c and 8th ,

Turbomachine, in particular axial compressor, with at least one vane ring, which comprises at least one row of adjustable guide vanes, wherein each vane in a side view of the vane with respect to its blade in the direction of its longitudinal axis has a taper. To increase the stability of the flow in the turbomachine, each row of vanes includes first vanes and second vanes, wherein in a common side view of a first vane and a second vane, each first vane has a taper in a longitudinal direction along its airfoil and every other vane having a taper in an opposite direction.

LIST OF REFERENCE NUMBERS

1

First vane

1a

Leading edge (first LS)

1b

Trailing edge (first LS)

1c

Rejuvenation (first LS)

2

Second vane

2a

Leading edge (second LS)

2 B

Trailing edge (second LS)

2c

Rejuvenation (second LS)

3

longitudinal axis

4

channel height

4a

Inner area

4b

Outer area

4c

Coverage area

5

Step transition

6

slope

7

curvature

8th

unit

9

vane ring

Claims (15)

1. Fluid flow engine, in particular an axial compressor, having at least one guide blade assembly (9) that comprises at least one row of adjustable guide blades (1,2), wherein each guide blade (1, 2) has, in a side view of the guide blade (1, 2) with respect to its turbine blade, a taper (1c, 2c) in the direction of its longitudinal axis (3), characterised in that each row of guide blades comprises first guide blades (1) and second guide blades (2), wherein, in a mutual side view of a first guide blade (1) and a second guide blade (2), each first guide blade (1) has a taper (1c) in a longitudinal direction along its turbine blade and each second guide blade (2) has a taper (2c) in an opposite direction.
2. Fluid flow engine according to claim 1, characterised in that at least one first guide blade (1) and at least one second guide blade (2), preferably two or three guide blades (1, 2) in total, form a unit (8) and a plurality of these units (8) are distributed evenly in the peripheral direction of the guide blade assembly, wherein the spaces between adjacent guide blades (1, 2) are of a different or the same size.
3. Fluid flow engine according to claim 1 or 2, characterised in that the second guide blades (2) are arranged opposite the first guide blades (1) of the same row in the axial direction of the fluid flow engine in the same position, or with displacement relative to one another.
4. Fluid flow engine according to one of the preceding claims, characterised in that the first guide blades (1) and the second guide blades (2) have an overlap region (4c) in the mutual side view, wherein the overlap region (4c) has a straight, angular or curved progression in the axial direction of the fluid flow engine.
5. Fluid flow engine according to claim 4, characterised in that the overlap region (4c) lies in a range of 30% tc 70% of a passage height (4) defined by a length of the turbine blade of each first guide blade (1) and each second guide blade (2).
6. Fluid flow engine according to one of claims 1 to 5, characterised in that the taper (1c) of each first guide blade (1) is formed on the rear edge (1b) of the respective first guide blade (1) and the taper (2c) of each second guide blade (2) is formed or the rear edge (2b) of the respective second guide blade (2).
7. Fluid flow engine according to one of claims 1 to 5, characterised in that the taper (1c) of each first guide blade (1) is formed on the front edge (1a) of the respective first guide blade (1) and the taper (2c) of each second guide blade (2) is formed on the front edge (2a) of the respective second guide blade (2).
8. Fluid flow engine according to one of claims 1 to 5, characterised in that the taper (1c) of each first guide blade (1) is formed or the rear edge (1b) of the respective first guide blade (1) and the taper (2c) of each second guide blade (2) is formed on the front edge (2a) of the respective second guide blade (2).
9. Fluid flow engine according to one of claims 1 to 5, characterised in that the taper (1c) of each first guide blade (1) is formed on the rear edge (1b) and on the front edge (1a) of the respective first guide blade (1) and the taper (2c) of each second guide blade (2) is formed on the rear edge (2b) and on the front edge (2a) of the respective second guide blade (2).
10. Fluid flow engine according to one of claims 1 to 9, characterised in that each taper (1c, 2c) is formed by a single or double curve (7), or each taper (1c, 2c) is formed by a graduation having at least two stepped transitions (5), wherein each stepped transition (5) is angular or rounded off.
11. Fluid flow engine according to one of the preceding claims, characterised in that the taper (1c, 2c) of each first guide blade (1) amounts to 30% to 70% of the maximum width of each second guide blade (2), or the taper of each second guide blade (2) amounts to 30% to 70% of the maximum width of each first guide blade (1).
12. Fluid flow engine according to one of the preceding claims, characterised in that the first guide blades (1) and the second guide blades (2) each have different curves of the mean lines of the blades and/or of the different profile formations in the same position along the longitudinal axis (3).
13. Fluid flow engine according to claim 12, characterised in that the first guide blades (1) and the second guide blades (2) each have, in the radial direction of the fluid flow engine, different curves of the mean lines and/or different profile formations in an outer region (4b) and an inner region (4a).
14. Fluid flow engine according to one of the preceding claims, characterised in that the first guide blades (1) and the second guide blades (2) can each be rotated around their longitudinal axis (3), wherein the first guide blades (1) and the second guide blades (2) can be rotated coupled together or independently of one another.
15. Method for increasing the stability of the flow in a fluid flow engine according to one of claims 1 to 14, characterised in that, in the radial direction of the fluid flow engine, each guide blade (1, 2) having an interior taper (1c, 2c) deflects the flow to the outside, and each guide blade (1, 2) having an exterior taper (1c, 2c) deflects the flow to the inside.

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