EP2455584A1 - Gasturbine comprising cooling control means which are made partially of Shape Memory Materials (SMM) - Google Patents

Abstract

The machine has a rotor, and a stator (28) including a swirl passage to guide a secondary flow of a cooling medium to a pre-swirl nozzle. A control unit completely or partially made of shape-memory alloy is arranged in an area of the pre-swirl nozzle to control the secondary flow based on temperature in an automated manner. The control unit includes a curved membrane made of shape-memory alloy and projected into the swirl passage, where the membrane changes flow cross section of the swirl passage by changing a curvature of the membrane. The control unit is selected from a group consisting of a membrane, an adjusting device (37), a wall element (38), a guide plate (39), an adjusting element (40), torsion elements, a cover, cover elements, and an elongation unit.

Description

TECHNICAL AREA

The present invention relates to the field of power generating machines. It relates to a rotary machine according to the preamble of claim 1.

STATE OF THE ART

In power-generating rotating machinery, such as gas turbines or electric generators, the required cooling of thermally stressed parts is a significant physical parameter that affects the overall efficiency and life of the system. In most cases, air is used as the coolant; but it can also steam, which is diverted from a steam generator, are used for the same purpose. The present invention, although exemplified by an air-cooled Gas turbine is not limited to a specific type of cooling and can therefore be used for all types of cooling media.

In Fig. 1 is shown in a section of a part of a gas turbine 10. In this gas turbine 10, intake air is compressed to a predetermined operating pressure by means of a compressor 11 comprising a compressor housing 31 and compressor vanes 32 and compressor blades 33, based on the ambient pressure. After compression, the stream of compressed air is split into a compressor air main stream 12 and a secondary stream 13. After the compressor air main flow 12 the hot part of (in Fig. 1 not shown) combustor, it is used in the combustion chamber for the combustion of a fuel to produce hot gas for operating a turbine. The secondary flow 13 of the compressed air is guided by the compressor 11 via cooling passages 14 to the high-temperature region 15 of the gas turbine 10. There, the coolant is used for the internal cooling of the vanes 16 and blades 17 of the turbine. In addition, the coolant reduces the temperatures at the vane mountings 18 and rotating parts, such as the blade roots 19 and blade necks 20, which are subjected to the highest centrifugal forces due to the rotational speed 21 of the rotor 22 about the machine axis 34.

Part of the air is also used for sealing purposes, particularly between the rotating and stationary parts of the gas turbine 10, such as between the stator 28 and the rotor 22 (see the sealing systems 23a, 23b and 23c in FIG Fig. 1 ). In this process, gaps are rinsed with air which is introduced into the hot-gas channel (see hot-gas main stream 29 in FIG Fig. 1 ) and thus prevents the entry of hot gas and thus a local overheating at this point.

It is common practice in this context to use special devices referred to as vortex nozzles arranged in spinal channels 27 (FIG. 24 in FIG Fig. 1 ), or vortex generators, to the branched off from the compressor 11 air to the high temperature region 15 of the turbine for cooling the Rotor 22 and the rotating hot parts, such as the blade roots 19, the blade necks 20 and the blade platforms 25 to lead.

Under operating conditions, the thermal load on the hot components of the turbine may decrease or increase, depending on whether the gas turbine 10 is driven under part load or full load. For example, a reduction of the output power of the gas turbine is usually caused by a lowering of the flame temperature in the combustion chamber. Depending on the demanded power, the gas turbine can be operated at full load and at partial load with full load equal to nominal operating conditions. The various operating conditions are controlled by variable guide vanes (VGV) in the compressor stages, which vary their stagger angle depending on the desired output power. This results in a maximum or lower mass air flow at a constant rotational speed 21.

gegeben, wobei Ω die Drehgeschwindigkeit 21 der Turbine und R der mittlere Radius am Auslass der Wirbelkanäle 27 ist (siehe Fig. 2). Die resultierende Luftgeschwindigkeit w beeinflusst die totale Temperatur T_t gemäss der Beziehung $$T_t=T+w^2/\left(2C_p\right),$$

wobei T die statische Temperatur und C_p die spezifische Wärme bezeichnen.The magnitude of the flow velocity c of the air behind vortex blades 26 arranged in the swirl channels 27 (see FIG Fig. 1 and 2 ) depends linearly on the mass flow in the swirl channels 27. For the normal operation of the gas turbine, which corresponds to the full load, the resulting velocity is w by the relationship $$w=2\pi \cdot R\cdot \mathrm{\Omega }\cdot c$$

where Ω is the rotational speed 21 of the turbine and R is the average radius at the outlet of the swirl channels 27 (see FIG Fig. 2 ). The resulting air velocity w affects the total temperature T _t according to the relationship $$T_t=T+w^2/\left(2C_p\right).$$

where T is the static temperature and C _{p is} the specific heat.

For a constant rotational speed Ω, the partial load is achieved by the variable guide vanes VGV, which reduce the mass flow in the compressor 11. Thereupon, the air velocity c behind the vortex device (swirl vanes 26) decreases. Eventually, the result will be the same Speed w affects what has direct effects on the metal temperatures of the rotating hot parts, such as the blade roots 19, the blade necks 20 and the platforms 25. If the metal temperature is kept constant at a constant rotational speed, the corresponding mechanical components are not subject to low-cycle fatigue (LCF). This could be achieved technically by controlled valves. In fact, however, the vortex device is usually not provided with control elements that can influence the mass flow in the cooling passages 14, since this region of the rotor 22 and the stator 28 has limited accessibility.

The control of the cooling air distribution in the rotor 22, in the stator 28 and in the turbine blades 27 is a complicated undertaking, which is further complicated by the requirement to avoid backflow. It follows that a simple throttling is not a good solution, and that it is advantageous to use a control device with an aerodynamically optimized design. One such device is vortex nozzle 24, which is usually formed by a stationary row of turbine blade-like vanes (swirl vanes 26 in FIG Fig. 3a ). These swirl vanes 26 are fixed to the stator 28 between the compressor 11 and the high-temperature region 15. Between the swirl vanes 26 a constriction 35 is formed ( Fig. 3b ) with a corresponding area F ( Fig. 3c ).

Could in the vortex nozzle 24 a simple, reliable automatic control of the mass flow can be realized in a simple manner, could be realized without great effort, a particularly effective cooling of the corresponding areas at different load conditions of the turbine.

From the publication GB 2 354 290 It is known to control the cooling air flow in a gas turbine through the interior of a turbine blade by means of a circular valve made of a memory alloy.

From the publication US 2009/0226327 A1 a similar solution is known in which sleeves of a memory alloy are used in the individual disks of the turbine, which change the cross-section of coolant channels depending on temperature.

In both cases, the main flow of the cooling medium is affected.

Furthermore, the document discloses GB 2 470 253 a device for controlling the flow of coolant in a gas turbine. Used is an annular current limiter, which is provided with distributed over the circumference arranged through holes. The flow cross section of the through holes can each be changed by a valve element whose position is changed relative to the bore by means of an SMM element. While an embodiment ( Fig. 5 ) relates to the previously known adjustment of the main flow through the blades, another embodiment ( Fig. 4 ) on the control of a secondary coolant flow in the sealing region of the rotor shaft.

The publication US 2002/076318 relates to the tangential injection of cooling air from the outside into the rotor of a gas turbine for cooling the rotor blades. The injection takes place with mixing of two separate streams, one of which is discharged from the interior of injection nozzles intended for injection. Control by changing the cross section, in particular using a memory alloy, is not disclosed.

PRESENTATION OF THE INVENTION

It is an object of the invention to provide a rotary machine, in particular a gas turbine, in which by controlling the coolant mass flow In a Secondary Air Flow Secondary Airflow (SAF), the efficiency of cooling and the efficiency of the machine can be improved.

The object is solved by the entirety of the features of claim 1. The invention is based on a rotating machine, in particular a gas turbine, which is cooled by a cooling medium, in particular cooling air, which cooling medium is passed through the machine in a main flow and a secondary flow. It is characterized in that the rotating machine comprises a rotor and a stator, that the secondary flow of the cooling medium is guided through vortex ducts in the stator to a Vorwirbeldüse and there emerges from the stator that control means for temperature-dependent, automatic control of the secondary flow in the Vorwirbeldüse are arranged, and that the control means entirely or partially consist of a memory alloy.

An embodiment is characterized in that vortex blades are arranged in the region of the Vorwirbeldüse, and that the control means are designed such that the flow cross-section of the vortex channels in the region of the vortex blades is temperature-dependent variable.

According to another embodiment, the control means each comprise a protruding into the spinal canal, a curved membrane made of a memory alloy, which changes the cross section of the vertebral canal by changing the curvature.

A further embodiment of the invention is characterized in that the control means each comprise a wall element arranged parallel to the wall in the vertebral channel, which is displaceable transversely to the wall by adjusting elements consisting of a memory alloy which change their length as a function of the temperature and which changes the cross section of the vertebral canal.

In particular, the adjusting elements are designed as bolts or springs.

Another embodiment is characterized in that the wall element is provided on the upstream side with a baffle, which introduces the medium flowing in the fluid passage in the narrowed through the wall element cross-section.

A further embodiment is characterized in that the swirl vanes are each arranged to be displaceable transversely to the flow direction in the swirl duct in a manner changing the cross section, and that adjusting elements are provided of a memory alloy in order to shift the swirl vanes in a temperature-dependent manner.

According to another embodiment, the displaceable vortex blades are each provided on the upstream side with a baffle, which introduces the medium flowing in the vortex channel into the narrowed by the swirl vanes cross-section.

A further embodiment of the invention is characterized in that the control means each comprise a torsion element of a memory alloy oriented in the direction of the longitudinal axis of the swirl blades, which changes the angle of attack of the swirl vanes and thus the flow cross section as a function of temperature.

Furthermore, it is conceivable that means for temperature-dependent covering of the outlet opening are arranged at the outlet of the swirl ducts.

In particular, the covering means may comprise a temperature-controlled diaphragm.

According to one embodiment, the diaphragm or its diaphragm elements consist of a memory alloy and change through temperature-dependent change in their dimensions, the cover of the outlet opening.

According to another embodiment, the diaphragms each consist of a plurality of diaphragm elements which are each coupled to torsion elements made of a memory alloy, which rotate the diaphragm elements in temperature-controlled manner and thus change the cover of the outlet opening.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

in einem Ausschnitt einen Teil einer Gasturbine mit verschiedenen Wegen für die Verteilung von Kühlluft;

Fig. 2

in einem vergrösserten Ausschnitt aus Fig. 1 die Ausgestaltung des Wirbelkanals;

Fig. 3

in verschiedenen Ansichten 3a-c die in der Vorwirbeldüse aus Fig. 1 angeordneten Wirbelschaufeln,

Fig. 4

in verschiedenen Teilfiguren 4b-f verschiedene Ausführungsbeispiele für eine selbsttätige Regelung des Kühlluft-Massenstroms im Wirbelkanal gemäss der Erfindung gegenüber der ungeregelten Anordnung (Fig. 4a);

Fig. 5

in zwei unterschiedlichen Ansichten 5a-b ein weiteres Ausführungsbeispiel für eine selbsttätige Regelung durch Verschwenken der Wirbelschaufeln;

Fig. 6

im Schnitt eine weitere Möglichkeit der selbsttätigen Regelung des Kühlluft-Massenstroms im Wirbelkanal durch selbsttätige Veränderung des Austrittsquerschnitts;

Fig. 7

in mehreren Teilfiguren 7a-c verschiedene Zustände bei einem Ausführungsbeispiel für eine selbsttätige Steuerung des Austrittsquerschnitts;

Fig. 8

in mehreren Teilfiguren 8a-b verschiedene Zustände bei einem anderen Ausführungsbeispiel für eine selbsttätige Steuerung des Austrittsquerschnitts;

Fig. 9

eine zu Fig. 7 vergleichbare Ausgestaltung, bei der die einzelnen Elemente jeweils selbsttätig um eine Achse gedreht werden und

Fig. 10

eine zu Fig. 8 vergleichbare Ausgestaltung, bei der die einzelnen Elemente jeweils selbsttätig um eine Achse gedreht werden.

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

Fig. 1

in a section of a part of a gas turbine with different ways for the distribution of cooling air;

Fig. 2

in an enlarged section Fig. 1 the embodiment of the spinal canal;

Fig. 3

in different views 3a-c in the Vorwirbeldüse Fig. 1 arranged swirl vanes,

Fig. 4

in different sub-figures 4b-f different embodiments of an automatic control of the cooling air mass flow in the swirl duct according to the invention with respect to the unregulated arrangement ( Fig. 4a );

Fig. 5

in two different views 5a-b another embodiment of an automatic control by pivoting the swirl vanes;

Fig. 6

on average another possibility of automatic control of the cooling air mass flow in the spinal canal by automatically changing the outlet cross section;

Fig. 7

in several sub-figures 7a-c different states in an embodiment for an automatic control of the outlet cross section;

Fig. 8

in several sub-figures 8a-b different states in another embodiment for an automatic control of the outlet cross section;

Fig. 9

one too Fig. 7 Comparable embodiment in which the individual elements are each automatically rotated about an axis and

Fig. 10

one too Fig. 8 comparable embodiment in which the individual elements are each automatically rotated about an axis.

WAYS FOR CARRYING OUT THE INVENTION

According to a preferred embodiment of the invention, the Vorwirbeldüse 24 in a gas turbine 10 after Fig. 1 constructed wholly or partly of a memory alloy (shape memory alloy SMA). Below a predetermined threshold temperature, which may be lower than the nominal operating temperature, the memory alloy part of the vortex nozzle 24 is activated and reduces the cross sectional area in the vicinity of the Vorwirbeldüse 24 constriction, whereby the cooling air mass flow into the high temperature region 15 of the gas turbine 10 effectively is reduced. Herein, shrinkage, stretching, torsion, and bending of the memory alloy parts can be used as a mechanism for reducing the flow area of the otherwise simple steel system. Fig. 4 shows in comparison to the arrangement without control ( Fig. 4a ) various examples of how an automatically controlled Vorwirbeldüse 24 can be realized by using different arrangements of a memory alloy due to different types of mechanical deformation ( Fig. 4b-f ). All examples are based on a reduction of area F in Fig. 3c by reducing the height of the vertebral canal 27 due to a translatory movement of an upper or lower wall element 38 or 44 (FIG. Fig. 4c-e ), a membrane 36 ( Fig. 4b ) or the swirl vanes 26 themselves ( Fig. 4f ).

In the example of Fig. 4b In the region of the blade tip of the swirl blade 26, a membrane curved into the swirl channel 27 is provided, the curvature of which changes and thus the flow cross section in the swirl channel 27.

In the example of Fig. 4c In the region of the blade tip of the swirl blade 26, an adjusting device 37 with a wall-parallel wall element 38 is provided, which can be displaced perpendicular to the wall by adjusting elements 40 built into corresponding housings from a memory alloy. The adjusting elements 40 can have the form of bolts or springs. An arranged in the flow direction in front of the wall member 38 (upstream) and adjustable with the wall member 38 baffle 39 directs the flow in the reduced by the wall member 38 cross-section.

In the example of Fig. 4d has the adjustment device 41 with otherwise the same structure as in Fig. 4c open adjusting elements 42 in the form of bolts or springs.

In the example of Fig. 4e the adjusting device 43 has a wall-parallel wall element arranged on the side of the blade root of the swirl blade 26 44 with associated baffle 45, which in turn can be moved by adjusting 42 of a memory alloy perpendicular to the wall.

In the example of Fig. 4f the vortex blade 26 itself is displaced by appropriate adjustment elements 46 of a memory alloy perpendicular to the wall to (by moving a platform) to change the cross section of the vertebral canal 27. Again, a baffle 47 is provided to direct the flow into the restricted cross section. Of course, the different adjustment mechanisms of Fig. 4 bf also be combined with each other.

Another example of a suitable adjustment mechanism is in Fig. 5 reproduced, wherein the partial figure a) a side view and the partial figure b) shows a view from above of the swirl vanes 26. The swirl vanes 26 in this example are rotatable about an axis oriented in the blade longitudinal direction which is formed by a torsion element 48 of a memory alloy. By appropriate rotation of the swirl vanes 26 (see solid and dashed lines in Fig. 5b ) changes the free flow area of the arrangement.

Another possibility is according to Fig. 6 to arrange at the outlet opening of the swirl channel 27, a diaphragm 49, which consists wholly or partly of a memory alloy and the outlet opening temperature changes (see dashed line to 49 in Fig. 6 ). When the power of the machine is reduced and thereby the hot gas, the compressed air or the metal temperature of any parts is changed, the orifice 49 closes progressively and reduces the mass flow of the cooling medium.

Is the aperture as in Fig. 7 shown, from a plurality of diaphragm elements 50, closes gradually the output of the spinal canal 27 as in the aperture of a camera ( Fig. 7a corresponds to full load, however Fig. 7b-c correspond to partial load of the turbine).

Depending on the shape of the vertebral canal 27, the diaphragm can also according to Fig. 8 as a composed of several aperture elements 51 lock gate be formed. Depending on the temperature of this lock gate, which consists wholly or partly of a memory alloy, the coolant flow in the spinal canal 27, or interrupts him completely. In this case, the individual diaphragm elements 51 are subject to an expansion 52 as a function of the temperature, which influences the coolant flow.

But it is also conceivable, the arrangement according to Fig. 7 or Fig. 8 to produce from a conventional material, in which case according to Fig. 9 or Fig. 10 The individual rotation elements 53 and 55 are impressed by a corresponding torsion element 54 or 56 from a memory alloy, the necessary rotational movement for changing the flow cross-section.

Overall, the present invention describes the use of memory alloys in the secondary coolant system of a rotating machine for efficiency-increasing control of the coolant consumption as a function of the load condition of the machine. The turbulence described in the embodiment can take different forms that require corresponding changes in the adjustment mechanism. The described self-regulating mechanism based on memory alloys can also be used in heat shields to control the coolant consumption as a function of the power (of the gas turbine).

The proposed arrangement may benefit from further lowering the coolant temperature relative to the total temperature in the rotating reference frame. This leads to the possibility to further reduce the required cooling air mass flows and thus to increase the performance and effectiveness of the gas turbine.

The memory alloy can consist of different metallurgical compositions of different elements and can also be produced with different technologies. A change in temperature and / or a mechanical change of the machine will start the process of geometry change of the memory alloy component. In the case of decreasing assembly tolerance, the shrinkage behavior of the component is considered instead of elongation.

Although the proposed mechanism has been explained using the example of a gas turbine, the memory alloy based coolant control can also be used in other machines where active automatic control of the coolant mass flow is required.

LIST OF REFERENCE NUMBERS

10

gas turbine

11

compressor

12

Compressor air-mainstream

13

secondary current

14

Cooling passage

15

High temperature range

16

vane

17

blade

18

Leitschaufelbefestigung

19

blade root

20

scoop-neck

21

rotation speed

22

rotor

23a-c

sealing system

24

Vorwirbeldüse

25

platform

26

swirl vane

27

spinal canal

28

stator

29

Hot gas main stream

31

compressor housing

32

Compressor vane

33

Compressor blade

34

machine axis

35

narrowing

36

membrane

37,41,43

adjustment

38.44

wall element

39,45,47

baffle

40,42,46

adjustment

48

torsion

49

cover

50,51,53,55

diaphragm element

52

expansion

54.56

torsion

F

area

Claims (13)

Rotating machine, in particular gas turbine (10), which is cooled by a cooling medium, in particular cooling air, which cooling medium in a main flow (12) and a secondary flow (13) through the machine (10) is guided, characterized in that the rotating machine (10) comprises a rotor (22) and a stator (28), that the secondary flow (13) of the cooling medium through vortex channels (27) in the stator (28) to a Vorwirbeldüse (24) is guided and there from the stator (28) emerges that control means (36-56) for the temperature-dependent, automatic control of the secondary flow (13) in the Vorwirbeldüse (24) are arranged, and that the control means (36-56) consist wholly or partly of a memory alloy. Rotary machine according to claim 1, characterized in that vortex blades (26) are arranged in the region of the Vorwirbeldüse (24), and that the control means (36-48) are designed such that the flow cross-section of the vortex channels (27) in the region of the vortex blades ( 26) is temperature-dependent variable. A rotating machine according to claim 2, characterized in that the control means (36-47) each comprise a curved membrane (36) of a memory alloy projecting into the vertebral canal (27), which by altering the curvature forms the cross-section of the vertebral canal (27). changed. A rotating machine according to claim 2, characterized in that the control means (36-47) each comprise a wall element (38, 44) arranged in a wall-parallel manner in the vortex channel (27), which, transverse to the wall, consists of a memory alloy, depending on the temperature Length-changing adjusting elements (40, 42) is displaceable and changes the cross-section of the swirl duct (27). Rotary machine according to claim 4, characterized in that the adjusting elements (40, 42) are designed as bolts or springs. Rotating machine according to claim 4 or 5, characterized in that the wall element (38, 44) on the upstream side with a baffle (39, 45) is provided, which flows in the vortex channel (27) flowing medium in the through the wall element ( 38, 44) introduces narrowed cross-section. A rotating machine according to claim 2, characterized in that the swirl vanes (26) are each arranged to be displaceable transversely to the flow direction in a swirling manner in the swirl duct (27), and that adjusting elements (46) are provided of a memory alloy in order to move the swirl vanes ( 26) depending on the temperature. Rotary machine according to claim 7, characterized in that the displaceable swirl vanes (26) are each provided on the upstream side with a baffle (47) which moves the medium flowing in the swirl duct (27) into the cross section narrowed by the swirl vanes (26) initiates. Rotary machine according to claim 2, characterized in that the control means each comprise a in the direction of the longitudinal axis of the swirl vanes (26) oriented torsion element (48) made of a memory alloy, which changes the angle of attack of the swirl vanes (26) and thus the flow cross-section temperature dependent. Rotary machine according to claim 1, characterized in that at the outlet of the swirl ducts (27) each means (49-51, 53-56) are arranged for the temperature-dependent covering of the outlet opening. A rotating machine according to claim 10, characterized in that the covering means (49-51, 53-56) comprise a temperature controlled shutter (49-51, 53-56). A rotating machine according to claim 11, characterized in that the diaphragm (49) or its diaphragm elements (50, 51) consist of a memory alloy and change the cover of the outlet opening by temperature-dependent change in their dimensions. Rotary machine according to claim 11, characterized in that the diaphragms each consist of a plurality of diaphragm elements (53, 55) which are each coupled to torsion elements (54, 56) of a memory alloy which rotate the diaphragm elements (53, 55) in a temperature-controlled manner and so on change the cover of the outlet opening.

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