EP1113144B1 - Cooled fluid directing means for a turbomachine working at high temperatures - Google Patents

Description

TECHNICAL AREA

The present invention relates to the field of thermal machines. It relates to a cooled Strömungsumlenkvorrichtung for working at high temperatures turbomachine according to the preamble of claim 1.

Such a flow diverter is well known, for example, in the form of a cooled guide or blade for a gas turbine engine of the prior art.

STATE OF THE ART

Today's flow diverters, especially vanes or blades in a gas turbine, are exposed to ambient temperatures that are above the allowable material temperature. The use of special internal cooling channels allows the lowering of the metal temperature to a value corresponding to the life of the device.

In the Fig. 1 and 2 is reproduced in cross-section or longitudinal section of an exemplary blade of a gas turbine, as it is currently used. The blade 10 consists essentially of an airfoil 11 and a blade root 12, with which it is attached to the rotor of the gas turbine. In the interior of the (hollow) airfoil 11 extend in the longitudinal direction of the blade 10 a plurality of cooling channels 17, through which a through the blade root 12 entering cooling fluid, usually cooling air, flows. The cooling fluid passes coolingly along the inner sides of the hot gas walls 14 in the cooling channels 17 and then exits (for film cooling) through corresponding film cooling holes located at the leading edge 18, the trailing edge 19 and at the blade tip (the effluent cooling fluid is at Fig. 2 represented by the arrows). The individual cooling channels 17 are separated from one another by partitions 13, which at the same time ensure by deflections 16 that the cooling fluid flows through adjacent cooling channels one after the other in alternating directions.

So far, and here especially with rotating guide devices such as the blades, the cooling channels 17 and their partitions 13 are poured.

• der Uebergangsbereich (15 in Fig. 1) von der Heissgaswand 14 zur Trennwand (Rippe) 13 ist durch die lokale Materialanhäufung ein schlecht zu kühlender Bereich. Ein erhöhter Wärmeübergang verbunden mit erhöhtem Kühlluftverbrauch ist notwendig, um dort eine ausreichende Festigkeit zu sichern.
• durch die von Kühlluft umspülten kalten Trennwände (Rippen) 13 kommt es zu thermischen Spannungen mit der Heissgaswand 14.
• ein Giessen der internen Kanäle führt zu einem hohen Schaufelgewicht, welches sowohl für den Schaufelfuss 12 als auch Ufer das Schaufelblatt 11 zu hohen Fliehkraftspannungen führen kann.
• der komplizierte Guss verlängert die Gussentwicklung und erhöht den Ausschuss.

The known cast partitions 13 and deflections 16, which are also referred to as ribs, however, have several disadvantages:

• the transition area (15 in Fig. 1 ) from the hot gas wall 14 to the partition (fin) 13 is a poorly cooled area due to the local accumulation of material. An increased heat transfer associated with increased Cooling air consumption is necessary to ensure sufficient strength there.
• due to the cold partition walls (ribs) 13 surrounded by cooling air, thermal stresses occur with the hot gas wall 14.
• a casting of the internal channels leads to a high blade weight, which can lead to the blade 11 to high centrifugal force both for the blade root 12 and shore.
• the complex font prolongs the casting development and increases the reject.

From the US-A-3,369,792 For example, a turbine blade vane is known in which thin, straight dividers are inserted in the hollow interior to form counter-rotating radial cooling channels.

From the US-A-2,817,490 is known a blade in which the interior is divided by incorporating a plurality of parallel, equal length sheet metal strips in a plurality of channels in which the cooling medium flows without deflection in parallel.

From the US-A-4,257,734 a gas turbine vane is known in which a division of the interior is effected by sheet metal inserts, without the interconnected, antiparallel cooling channels with deflection arise.

In the US-A-5,193,980 discloses a blade of a turbine engine, in which the subdivision into parallel cooling channels without deflection by inserted sheet metal parts is made.

From the JP-A-09 151 703 is known a blade in which inside a baffle cooling is caused by wall-parallel inserts.

The US-A-4,252,501 discloses a comparable arrangement of inserts in a cooled blade.

From the US-A-5,507,621 a gas turbine vane is known in which a deflection aid in the form of a bent sheet metal insert is arranged in the connecting region of two counter-rotating, radial cooling channels which are separated by solid, cast walls.

The EP-A-0 534 586 shows a gas turbine blade in which a preferably cast, separate baffle is firmly inserted between two separate front and rear parts of the blade.

From the US-A-3,806,275 Finally, a cooled turbine blade is known in which the perforated sheet metal inserts the turbulent cooling of the inner walls is improved.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a cooled Strömungsumlenkvorrichtung, which avoids the disadvantages of the known devices listed and in particular easy to manufacture, flexibly adaptable to the particular application, and is efficiently cooled.

The object is solved by the entirety of the features of claim 1. The essence of the invention is to no longer produce the delimiting the cooling channels serving partitions together with the device, in particular to pour, but form as a separate bays, which are later inserted into the device and fixed there. It is particularly simple and inexpensive, characterized in that the cooling fluid flows in opposite directions in two adjacent cooling channels, the cooling fluid is deflected from the output of a cooling channel in the input of the other cooling channel by means of a deflection, and the deflection is generated by a U-shaped curved partition ,

The invention thus differs significantly from solutions such as those in the US-A-5,145,315 or the US-A-5,516,260 are described in which special inserts are used in cast cooling ducts for special steering of the cooling fluid.

• es findet keine Materialanhäufung im Uebergangsbereich von Heissgaswand zum Einschub (zur Trennwand) statt.
• es kommt zu keinen thermischen Spannungen zwischen Einschub (Trennwand) und der Heissgaswand.
• bei rotierenden Schaufeln werden das Schaufelgewicht und somit die Fliehkraftspannungen sowohl im Schaufelfuss als auch im Schaufelblatt reduziert.
• bei gegossenen Schaufeln wird der Gusskern einfacher, wodurch sowohl seine als auch die Herstellbarkeit der Schaufel einfacher werden.
• es wird ein einfache Justierbarkeit des Kühlsystems durch einen Austausch der Einschübe möglich, durch z.B. Aendern des Umlenkungsradius bei Umlenkungen oder Einfügen von Verbindungsquerschnitten zwischen zwei Kühlkanälen.

The use of inserts made of metal or non-metal materials (for blades, for example through the blade root or through the blade tip) as a substitute for cast partitions and possibly deflections has several advantages:

• There is no accumulation of material in the transition region of hot gas wall to the insert (to the partition) instead.
• There are no thermal stresses between the insert (dividing wall) and the hot gas wall.
• with rotating blades, the blade weight and thus the centrifugal force stresses are reduced both in the blade root and in the blade.
• with cast blades, the casting core becomes simpler, making both its and the manufacturability of the blade easier.
• it is a simple adjustability of the cooling system by replacing the bays possible by, for example, change the radius of deflection in deflections or insertion of connecting sections between two cooling channels.

A first preferred embodiment of the Strömungsumlenkvorrichtung according to the invention is characterized in that the Strömungsumlenkvorrichtung is formed as a hollow cast part, and in that the rail of the flow deflection are formed in the form of receptacles, in which the partitions are inserted. As a result, assembly and attachment of the bays are significantly facilitated, as well as a good marginal tightness of the partitions or bays scored. The partitions are preferably formed as flat strips of a metallic or heat-resistant non-metallic (ceramic or composite) material.

A secure fit of the inserts is achieved when according to a second preferred embodiment of the invention, the inserted partitions for attachment cohesively, preferably by soldering or welding, are connected to the Strömungsumlenkvorrichtung.

In the simplest form, the partitions can be straight.

A particularly preferred embodiment of the Strömungsumlenkvorrichtung according to the invention is characterized in that the Strömungsumlenkvorrichtung is a blade of a gas turbine. This results in considerable simplifications due to the comparatively complicated geometry of the blade by the invention.

Another embodiment, which is particularly advantageous for rapidly rotating blades, is characterized in that the cooling channels or partitions extend substantially in the radial direction with respect to the axis of rotation of the gas turbine, that the inserted partitions for fastening cohesively, preferably by Soldering or welding, are connected to the blade, and that the material connection is arranged at the near-axis end of the partition walls.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

den Querschnitt durch eine Turbinenschaufel mit gegossenen Kühlkanälen nach dem Stand der Technik;

Fig. 2

den Längsschnitt durch die Schaufel gemäss Fig. 1;

Fig. 3

den zu Fig. 1 vergleichbaren Querschnitt durch eine Schaufel gemäss einem Ausführungsbeispiel der Erfindung; und

Fig. 4

den zu Fig. 2 vergleichbaren Längsschnitt durch die Schaufel nach Fig. 3.

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it

Fig. 1

the cross section through a turbine blade with cast cooling channels according to the prior art;

Fig. 2

the longitudinal section through the blade according Fig. 1 ;

Fig. 3

which to Fig. 1 comparable cross section through a blade according to an embodiment of the invention; and

Fig. 4

which to Fig. 2 comparable longitudinal section through the blade after Fig. 3 ,

WAYS FOR CARRYING OUT THE INVENTION

In the FIGS. 3 and 4 is an embodiment of a cooled Strömungsumlenkvorrichtung according to the invention in the form of a blade for a gas turbine reproduced in cross-section or longitudinal section. The blade 20 is similar in geometry to the prior art blade 10 of FIGS Figures 1 and 2 ,

The blade 20 in turn consists essentially of an airfoil 21 and a blade root 22, with which it is attached to the rotor of the gas turbine. In the interior of the (hollow) airfoil 21, a plurality of cooling passages 27 extend in the longitudinal direction of the blade 20 through which a cooling fluid entering through the blade root 22 flows. The cooling fluid sweeps in the cooling channels 27 cooling along the inner sides of the hot gas walls 24 along and also exits through corresponding film cooling openings to the outside, which are arranged at the leading edge 28, the trailing edge 29, and at the blade tip. The individual cooling channels 27 are separated from one another by partitions 23, which at the same time ensure, by means of deflections 26, that the cooling fluid flows through adjacent cooling channels one after the other in alternating directions.

In contrast to Fig. 1 and 2 Here, however, the partitions 23 are not cast, ie, produced together with the blade 20 in one cast, but the partitions 23 are formed as separate, strip-shaped inserts, which are introduced after the casting of the blade 20 through the blade root 22 or the opposite blade tip , Thus, the partition walls 23 introduce selectively and secure after insertion, rail-shaped receptacles 30 are integrally formed on the inner sides of the hot gas walls, in which the partitions 23 are guided during insertion with the longitudinal edges.

The partitions (slots) 23 may have any shape. You can e.g. just be. If a plurality of cooling channels are connected to each other by deflections 26, it is advantageous if the partitions 23 are bent in a U-shape. The dividing walls 23 may be fixed on one or more sides, e.g. by soldering or welding. They can be fixed in the blade tip area or in the blade root area. The latter has the advantage that the insert or the partition is loaded in the occurring centrifugal forces to train, and so bulging is avoided.

Basically, the retractable partitions are provided immediately in the manufacture of the blades. However, it is also conceivable within the scope of the invention, according to completely cast blades Fig. 1 and 2 later to remove the cast partitions and insert and fix separate partitions as a replacement.

LIST OF REFERENCE NUMBERS

10.20

shovel

11.21

airfoil

12.22

blade root

13

Partition (rib)

14:24

Heissaaswand

15.25

The transition area

16.26

redirection

17.27

cooling channel

18.28

leading edge

19.29

trailing edge

23

insertion

30

Recording (rail-shaped)

Claims (8)

1. Cooled flow deflection apparatus (20) for a fluid-flow machine which operates at high temperatures, which flow deflection apparatus (20) has, in the interior, a number of parallel-running cooling channels (27), which are separated from one another by separating walls (23) for a cooling fluid to pass through, the cooling fluid flowing in mutually opposite directions in two adjacent cooling channels (27), and the cooling fluid is deflected from the outlet of the one cooling channel into the inlet of the other cooling channel by means of a deflection device (26), and the separating walls (23) being in the form of separate inserts which can be pushed into the flow deflection apparatus (20) subsequently, characterized in that the deflection (26) is produced by a separating wall (23) which is bent into a U-shape.
2. Flow deflection apparatus according to Claim 1, characterized in that the flow deflection apparatus (20) is in the form of a hollow casting, and in that holders (30), which are in the form of rails and into which the separating walls (23) are inserted, are integrally formed in the interior of the flow deflection apparatus (20).
3. Flow deflection apparatus according to one of Claims 1 and 2, characterized in that the separating walls (23) are in the form of flat strips.
4. Flow deflection apparatus according to one of Claims 1 to 3, characterized in that the inserted separating walls (23) are connected by an integral material joint to the flow deflection apparatus (20), in order to secure them.
5. Flow deflection apparatus according to Claim 4, characterized in that the inserted separating walls (23) are connected to the flow deflection apparatus (20) by soldering or welding, in order to secure them.
6. Flow deflection apparatus according to one of Claims 1 to 5, characterized in that the flow deflection apparatus is a blade (20) in a gas turbine.
7. Flow deflection apparatus according to Claim 6, characterized in that the blade (20) is a rotor blade, in that the cooling channels (27) and separating walls (23) extend essentially in the radial direction with respect to the rotation axis of the gas turbine, and that the inserted separating walls (23) are connected by an integral material joint to the blade (20), in order to secure them.
8. Flow deflection apparatus according to Claim 7, characterized in that the inserted separating walls (23) are connected to the blade (20) by soldering or welding, in order to secure them.

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