EP3336313A1 - Turbine rotor blade arrangement for a gas turbine and method for the provision of sealing air in a turbine rotor blade arrangement - Google Patents

Abstract

The invention relates to a turbine rotor blade assembly (50) for a gas turbine having a turbine disk (51) and a turbine blade ring comprising a plurality of blades (52). The turbine disk (51) has disk channels (53) for providing air, wherein a disk channel (53) in each case in the region of a Schaufelfußaufnahme (57) in an outlet opening (530) ends. The blades (52) have cooling air passages for cooling the blades (52). In the blade root (521) or between the blade root (521) and the Schaufelfußaufnahme (57) an air passage (55, 551-553) is formed, exits through the sealing air, which is fed from the disc channel (53). It is provided that the blade root (521) has a deflection device (3, 31-39, 45), which is provided and designed for air, which emerges from the pulley channel (53), partially in the direction of the air channel (55, 551). 553) to redirect. The invention further relates to a method of providing sealing air in a turbine blade assembly.

Description

The invention relates to a turbine blade assembly according to the preamble of claim 1 and a method for providing sealing air in a turbine blade assembly.

It is known to cool the turbine blades of a gas turbine. To cool the turbine blades, these have internal cooling air channels that are exposed to air that is provided via a disk channel in the turbine disk. The disc channels end up at the Schaufelfußaufnahmen the turbine disk, which receive the blade roots of the turbine blades. A part of the air emerging from a disk channel escapes as a leakage flow through a gap formed between the blade root and Schaufelfußaufnahme and extending in the axial direction. The air which escapes through the gap as a leakage flow is referred to as sealing air, since there is a driving pressure ratio above the gap and the air can be used for sealing. The exiting from a disc channel air is thus referred to as cooling air, provided that it serves cooling purposes and referred to as sealing air, if they are as leakage flow escapes, wherein sealing air can generally also be used for cooling various components.

In unfavorable operating conditions or component tolerances there is a risk that the driving pressure ratio over the gap between the blade root and Schaufelfußaufnahme reduces and leads to a reversal of the leakage flow. Since this leakage flow also constitutes a portion of the sealing air which seals against hot air from the main flow channel of the gas turbine, which has very high temperatures immediately behind the combustion chamber, there is the risk that such hot air flows in front of the turbine disk and further into the turbines via said gap Blade penetrates and damages the disc.

From the US 4,505,640 A a turbine blade assembly is known in which the gap formed between the blade root and Schaufelfußaufnahme is sealed by a seal to minimize the leakage flow.

The present invention is based on the object to provide a turbine blade assembly and a method for providing sealing air, the air ducts, which are formed in the blade root or between the blade root and Schaufelfußaufnahme safely protect against hot air.

This object is achieved by a turbine blade assembly with the features of claim 1 and by a method having the features of claim 14. Embodiments of the invention are specified in the dependent claims.

Thereafter, the present invention is based on a turbine blade assembly including a turbine disk and a turbine blade ring. The turbine disk is rotatable about a machine axis of the gas turbine and has a plurality of Schaufelfußaufnahmen on its periphery. The turbine blade ring comprises a plurality of blades each comprising a blade root and secured to the periphery of the turbine disk by locating the blade roots in the blade root seats. The turbine disk includes disk passages which serve to provide air and which run with a radial directional component. A disc channel ends in each case in the region of a Schaufelfußaufnahme in an outlet opening. The blades have cooling air channels for cooling the blades. The disc channels of the turbine disc and the cooling air channels of the Blades are designed and arranged such that during operation, air is supplied via the disk channels of the turbine disk to the cooling air passages of the rotor blades. The air emerging from a disk channel in this case has a radial direction component.

The blades of the turbine blade assembly under consideration further comprise at least one air passage in the blade root or between the blade root and the blade root receiver, via which sealing air which is fed from the pulley channel emerges. Over the air duct sealing air, which emerges from the disc channel, led away from the blade root.

The present invention provides that the blade root has a deflection device, which is provided and designed to redirect part of the air emerging from the disk channel, in the direction of the air duct. By the targeted deflection of the air emerging from the disc channel through the deflection device provided for this purpose, a portion of the dynamic pressure component of the air emerging from the disc channel is maintained and the driving pressure ratio is thus increased over the air channel.

The present invention is based on the finding that by providing a deflection device arranged in or on the blade root, the dynamic pressure of the air flow is maintained, which leads to an increase in the total pressure. Such an increase in pressure is associated with several advantages. A first advantage is that due to the increased pressure, the risk is banned that flow under unfavorable operating conditions hot gas from the main flow channel through the air duct into the blade or a flow reversal takes place in the air duct. The risk of damage to the blades by hot gas is eliminated.

Another advantage is that the sealing air, which flows with increased total pressure ratio across the air duct, can be used to reliably fulfill other functions in the gas turbine. Such a function is, for example, to use the air flowing out of the air duct to the seal. In particular, it may be provided to apply to this air seals, which are formed in the edge region of the main flow channel of the gas turbine between the rotating turbine blade assembly and adjacent, non-rotating structures, in particular an adjacent turbine vane ring (so-called "rim seals" or Radseitenraumdichtungen). Another feature that can be realized by the increased total pressure, there is in the targeted use of this air to realize or support a so-called microturbine. The concept of a microturbine is in the EP 1 004 748 B1 described, to which reference is made.

Another advantage associated with the invention is that, due to the increase of the total pressure in the air duct provided by the deflection device, the diameter of the disk channels formed in the turbine disk can be reduced. Because a sufficient pressure build-up can be provided due to the invention even with comparatively small pulley channels. By reducing the diameter, without the present invention, the pressure loss (loss of expansion) increases as it transitions into the cavity within the blade root. This can be compensated by the invention, which allows a reduction of the disk channel diameter, thereby reducing stress peaks and thus increasing the stability of the turbine disk.

In the air duct, in which cooling air is deflected by means of the deflecting device, it is, for example, the gap which extends in the axial direction between the blade root receiver and the blade root arranged therein. The deflection device is arranged on the underside of the blade root. Air emerging from the outlet opening of the disk channel is thus deflected by means of the deflecting device on the underside of the blade root and transported in the air channel formed by the gap between the blade root and blade receptacle with sufficient dynamic pressure.

However, it should be noted that the air channel may be formed in other ways than through the gap between the blade root and blade receptacle. For example, it can be provided that the blade root forms a cavity into which flows at least part of the air before it is passed as cooling air into the cooling air channels of the blade. It can be provided that extend one or more air channels in the blade root of such a Schaufelfußhohlraum to an opening formed at the front edge or at the trailing edge of the blade root. The orientation of the flow in the air duct can be adjusted via the radial distance of the opening from the underside of the blade root and its orientation.

According to one embodiment of the invention it is provided that the deflection device partially covers the outlet opening of the disk channel. The term overlap refers to a view from above (opposite to the radial direction) on the outlet opening. By a partial overlap of the outlet opening, a targeted deflection of the air emerging from the disc channel can be carried out in a particularly effective manner. In particular, it can be provided that the deflecting device in a view from above onto the outlet opening partially covers it along exactly one boundary line.

However, it is not absolutely necessary for the intended diversion of the air emerging from the window channel according to the invention that the deflection device partially cover the outlet opening of the window channel. For the intended deflection of the air, it is only necessary that the deflection device is detected by the emerging from the disc channel air. This is in addition to the case of the overlap also the case when the exiting the disc channel airflow is divergent and due to its expansion partially flows against the deflection device. It is true that the emerging from the disc channel airflow widens with increasing distance from the outlet opening.

An embodiment of the invention provides that the deflection device is arranged and designed such that air is deflected from the disk channel in the direction of the leading edge of the blade root in the air channel. The deflection is thus upstream relative to the flow direction in the main flow channel. Alternatively it can be provided that sealing air in the direction of the trailing edge of the blade root, i. downstream of the flow direction in the main flow channel of the gas turbine is deflected into the air duct. In the latter case, the sealing air is used, for example, to cool or seal components which are arranged in the axial direction behind the turbine blade assembly. It can also be provided in principle that the blade has a plurality of deflection devices, which redirect the sealing air into different air ducts and, for example, make a diversion on the one hand in the direction of the leading edge and on the other in the direction of the trailing edge of the blade root.

A further embodiment of the invention provides that the deflection device forms the initial region of the respective air channel. It forms the radially outer boundary of the air duct and goes smoothly into the air duct. Alternatively, the air duct begins only at a distance from the deflection device, in which case the Deflector directs air in the direction of the air duct without already being part of the air duct.

The deflection device can basically have a multiplicity of geometric shapes and structural configurations. For example, the deflection device form a flat surface, is deflected at the air. In the simplest case, the deflection device is a planar sheet metal which partially covers the outlet opening of the disk channel and thereby directs air emerging from the disk channel into the air channel and thereby increases the total pressure ratio via the passage. However, in this simplest embodiment of the occurring on the flat surface dynamic pressure loss is relatively large, whereby a comparatively low effect is achieved.

An alternative embodiment provides that the deflection device, at least in the region which is detected by the air emerging from the disk channel, forms a concave surface which runs concavely to the disk channel or to the air flow exiting therefrom. It can be provided that the concave surface smoothly merges into the air duct. The design of the deflection device with a surface that is concave toward the disk channel makes it possible to deflect the airflow emerging from the disk channel with little loss into the air channel, avoiding perpendicularly to the flow direction arranged impact body. As a result, a large part of the dynamic pressure can be recovered and thus the driving pressure ratio can be increased significantly over the air duct. If the deflecting device partially covers the outlet opening of the disk channel, according to one embodiment the deflecting device forms a concave surface, at least in the area partially covering the outlet opening of the disk channel, which runs concave to the disk channel or to the air flow exiting therefrom.

In order to keep the occurring dynamic pressure losses during the deflection of the sealing air low, according to an embodiment of the invention, a deflection device and an air duct can be provided which realize widths and radii of curvature such that the relationship r_m / w> 1 is satisfied, where w is the mean Width of the air duct in the region of the deflecting device and r_m is the average of a first, outer radius of curvature r_o and a second, inner radius of curvature r_i, wherein the first radius of curvature r_o the radius of curvature of the concave surface of the deflecting device and the second radius of curvature r_i the radius in the transition from the Disc channel to the leading edge of Schaufelfußaufnahme represents.

An embodiment of the invention provides that the deflection device is formed by a nose-shaped component. Its end faces the disc channel or the outlet opening. It can be provided that the end of the nose-shaped component partially covers the outlet opening of the disk channel. "Nose-shaped" here means that the nose-shaped component in the circumferential direction of the turbine disk is not or only slightly wider than the outlet opening of the disk channel.

A further embodiment provides that the deflection device in a view from above onto the outlet opening (i.e., on a plane normal to the radial direction) partially covers it along a straight boundary line. In alternative embodiments, this boundary line is concave or convex to the outlet opening formed. The boundary line can be formed, for example, circular, elliptical, parabolic or hyperbolic.

According to one embodiment of the invention, the overlap of the outlet opening of the disk channel in a view from above on the outlet opening is at least 10% of the total cross-sectional area of the outlet opening. In particular, the coverage may be in the range between 10% and 25%, in particular in the range between 15% and 20% of the total cross-sectional area of the outlet opening. The degree of overlap is to be optimized so that on the one hand provided a sufficient total pressure in the air duct and on the other hand, the cooling air supply of the blade channels and thus the cooling of the blades is not affected.

In a further embodiment of the invention can be provided that the air duct is aligned in its end portion, ie in the portion which adjoins the opening of the air duct in the region of the leading edge or trailing edge of the blade root, at an angle to the axial direction of the gas turbine. This ensures that sealing air is directed at an angle into the cavity adjacent to the blade. The flow of work is taken, whereby the blades are additionally accelerated. It can be provided that the air ducts are formed toward their output as a nozzle. Such an embodiment is also referred to as a microturbine and is in the EP 1 004 748 B1 described in detail.

By providing a sufficient dynamic pressure in the air duct due to the deflection of the air according to the invention, it is possible, such Rotor acceleration can also be achieved in cooling air passages that extend to the front edge of the blade root.

The deflection device may be an integral part of the blade root. For example, it is realized by a component which is produced together with the blade root as a casting or by machining processes. Alternatively, the deflection device may be a separately manufactured component that is connected to the underside of the blade root after production of the blade root. In this embodiment, the deflection device can be provided as a retrofit device for already manufactured turbine blade assemblies. For example, a flat or curved plate is attached to the underside of the blade root in such a way that it partially covers the outlet opening of the disk channel.

According to one embodiment of the invention it is provided that the deflection device is a continuous or continuous component insofar as it has no holes or perforations for a flow of air.

The present invention also relates to a method for providing sealing air in a turbine blade assembly comprising a turbine disk and a turbine blade ring, wherein air is supplied via disk disks formed in the turbine disk, each ending in the area of a blade root receiver in an exhaust port, and in Cooling air channels of the blades of the turbine blade ring is blown. It is envisaged that emerging from the disc channel air is deflected by means of a deflecting device partially in the direction of an air duct over which the air is passed as sealing air away from the blade root. It can be provided that the deflection device partially covers the outlet opening of the disk channel. If the air leaving the disc channel is divergent, this is not necessarily the case.

Figur 1

eine vereinfachte schematische Schnittdarstellung eines Turbofantriebwerks, in dem die vorliegende Erfindung realisierbar ist;

Figur 2

schematisch eine Turbinen-Laufschaufelanordnung gemäß dem Stand der Technik, die eine Turbinenscheibe und einen Turbinen-Laufschaufelkranz umfasst;

Figur 3

ein Ausführungsbeispiel einer Turbinen-Laufschaufelanordnung, die eine Umlenkvorrichtung in Form eines konkav ausgebildeten Bauteils umfasst, die Luft in einen Luftkanal umlenkt, der zwischen dem Schaufelfuß und der Schaufelfußaufnahme ausgebildet ist;

Figur 4

ein Ausführungsbeispiel einer Turbinen-Laufschaufelanordnung, die eine Umlenkvorrichtung in Form eines konkav ausgebildeten Bauteils umfasst, die Luft in einen Luftkanal umlenkt, der an der Vorderkante des Schaufelfußes in radialem Abstand zur Unterseite des Schaufelfußes endet;

Figur 4A

eine Abwandlung des Ausführungsbeispiels der Figur 4, wobei die Umlenkvorrichtung in Form eines konkav ausgebildeten Bauteils die Austrittsöffnung des Scheibenkanals nicht teilweise überdeckt, jedoch von der aus dem Scheibenkanal austretenden Luft erfasst wird;

Figur 4B

eine vergrößerte Darstellung des Bereichs der Turbinen-Laufschaufelanordnung der Figur 4A, die die Umlenkvorrichtung ausbildet;

Figur 5

ein Ausführungsbeispiel einer Turbinen-Laufschaufelanordnung, bei der eine Umlenkvorrichtung in Form einer gewölbten, an der Unterseite des Schaufelfußes angebrachten Platte vorgesehen ist;

Figur 6

ein Ausführungsbeispiel, das beispielhaft und schematisch verschiedene Geometrien einer integral mit dem Schaufelfuß ausgebildeten Umlenkvorrichtung darstellt;

Figur 7

ein Ausführungsbeispiel, das beispielhaft und schematisch verschiedene Geometrien einer gesondert hergestellten und mit dem Schaufelfuß verbundenen Umlenkvorrichtung darstellt;

Figur 8

schematisch mehrere Ausführungsvarianten für die teilweise Überdeckung der Austrittsöffnung eines Scheibenkanals durch eine Umlenkvorrichtung;

Figur 9

ein weiteres Ausführungsbeispiel einer Turbinen-Laufschaufelanordnung unter Darstellung bestimmter geometrischer Parameter;

Figur 10

die Turbinen-Laufschaufelanordnung der Figur 2 in einer Ansicht von vorne; und

Figur 11

die Turbinen-Laufschaufelanordnung der Figur 4 in einer Ansicht von vorne.

The invention will be explained in more detail with reference to the figures of the drawing with reference to several embodiments. Show it:

FIG. 1

a simplified schematic sectional view of a turbofan engine in which the present invention is feasible;

FIG. 2

schematically a turbine blade assembly according to the prior art, which comprises a turbine disk and a turbine blade ring;

FIG. 3

an embodiment of a turbine blade assembly comprising a deflection device in the form of a concave component which deflects air into an air passage formed between the blade root and the Schaufelfußaufnahme;

FIG. 4

an embodiment of a turbine blade assembly comprising a deflection device in the form of a concave component which deflects air into an air duct which terminates at the leading edge of the blade root at a radial distance from the underside of the blade root;

FIG. 4A

a modification of the embodiment of FIG. 4 , wherein the deflection device in the form of a concave component does not partially cover the outlet opening of the disc channel, but is detected by the exiting from the disc channel air;

FIG. 4B

an enlarged view of the area of the turbine blade assembly of FIG. 4A that forms the deflection device;

FIG. 5

an embodiment of a turbine blade assembly in which a deflection device is provided in the form of a curved, attached to the underside of the blade root plate;

FIG. 6

an exemplary embodiment, which exemplarily and schematically represents different geometries of a deflecting device formed integrally with the blade root;

FIG. 7

an exemplary embodiment, which shows by way of example and schematically different geometries of a separately manufactured and connected to the blade root deflection device;

FIG. 8

schematically several embodiments for the partial overlap of the outlet opening of a disc channel by a deflection device;

FIG. 9

a further embodiment of a turbine blade assembly showing certain geometric parameters;

FIG. 10

the turbine blade assembly of the FIG. 2 in a view from the front; and

FIG. 11

the turbine blade assembly of the FIG. 4 in a view from the front.

The FIG. 1 1 schematically shows a turbofan engine 100 having a fan stage with a fan 10 as a low-pressure compressor, a medium-pressure compressor 20, a high-pressure compressor 30, a combustion chamber 40, a high-pressure turbine 50, a medium-pressure turbine 60 and a low-pressure turbine 70.

The medium-pressure compressor 20 and the high-pressure compressor 30 each have a plurality of compressor stages, each comprising a rotor stage and a stator stage. The turbofan engine 100 of FIG. 1 further comprises three separate shafts, a low pressure shaft 81 connecting the low pressure turbine 70 to the fan 10, a medium pressure shaft 82 connecting the medium pressure turbine 60 to the intermediate pressure compressor 20, and a high pressure shaft 83 connecting the high pressure turbine 50 to the high pressure compressor 30. However, this is only to be understood as an example. For example, if the turbofan engine did not have a medium pressure compressor and medium pressure turbine, only a low pressure shaft and a high pressure shaft would be present.

The turbofan engine 100 has an engine nacelle 1, which comprises an inlet lip 14 and, on the inside, forms an engine inlet 11, which supplies incoming air to the fan 10. The fan 10 has a plurality of fan blades 101 connected to a fan disk 102. The annulus of the fan disk 102 forms the radially inner boundary of the flow path through the fan 10. Radially outside the flow path is limited by a fan housing 2. Upstream of the fan disk 102, a nose cone 103 is disposed.

Behind the fan 10, the turbofan engine 100 forms a secondary flow channel 4 and a primary flow channel 5. The primary flow channel 5 passes through the core engine (gas turbine) comprising the medium pressure compressor 20, the high pressure compressor 30, the combustor 40, the high pressure turbine 50, the medium pressure turbine 60, and the low pressure turbine 70. In this case, the medium-pressure compressor 20 and the high-pressure compressor 30 are surrounded by a peripheral housing 29 that inside a Annular space surface which defines the primary flow channel 5 radially outward. Radially inside, the primary flow channel 5 is bounded by corresponding ring surfaces of the rotors and stators of the respective compressor stages or by the hub or hub connected to the elements of the corresponding drive shaft.

In operation of the turbofan engine 100, a primary flow passes through the primary flow passage 5, which is also referred to as the main flow passage. The secondary flow channel 4, also referred to as bypass duct, bypass duct or bypass duct, passes in the operation of the turbofan engine 100 by the fan 10 sucked air past the core engine.

The described components have a common axis of rotation 90. The axis of rotation 90 defines an axial direction of the turbofan engine. A radial direction of the turbofan engine is perpendicular to the axial direction.

In the context of the present invention, the design of the blade assembly, in particular the first stage of the high-pressure turbine 50 is important. However, the principles of the present invention are equally applicable to blade assemblies of other turbine stages.

The FIG. 2 shows schematically in sectional view a turbine blade assembly, as known from the prior art. The FIG. 10 shows such an arrangement in a front view. In the FIG. 2 x indicate the axial direction and r the radial direction. In a cylindrical coordinate system, the circumferential direction is perpendicular to x and r. The axial direction x may be identical to the machine axis of a gas turbine engine in which the invention is implemented, but may be different (if the blades are inserted into the blade root receivers at an angle to the machine axis).

The blade assembly includes a turbine disk 51 and a turbine blade ring with blades 52. The blades 52 each include a blade root 521 and an airfoil 522 that projects into a main flow channel 5 of the gas turbine engine. Via hot gases in the main flow channel 5, which transfer energy to the blades 522, the blade ring and the turbine disk 51 are set in rotation, wherein the turbine disk 51 about the machine axis of the gas turbine (see FIG. 1 ) and drives a drive shaft.

For attachment of the rotor blades 52 at an equidistant distance on the circumference of the turbine disk 51, the turbine disk 51 has at its periphery a plurality of blade root receivers 57, which each serve to receive a blade root 521 of a rotor blade 51. It is provided, for example, that the blade roots 521 are designed as so-called "pine tree feet" which ensure a distribution of the centripetal force absorption under centrifugal force loading. The Schaufelfußaufnahmen 57 are formed in a corresponding manner. The Schaufelfußaufnahmen 57 include, in particular in the FIG. 10 a bottom wall 510 and two circumferentially spaced sidewalls 511, 512 which are structured to hold the blade roots 521 in a positive fit.

The turbine disk 51 has disk channels 53 which serve to provide cooling air for cooling the rotor blades 52. The disk channels 53 each end in the region of a blade root receiver 57, namely in the bottom wall 510, where they form an outlet opening 530.

The blades 52 include cooling air channels 54 that serve to cool the blades 52. The exact shape of the cooling air channels 54 and the type of cooling are not important to the present invention. There is, for example, a film cooling and / or cooling by convection. The cooling air ducts 54 start from a cavity 56, which is formed in the blade root 521. From the pulley channels 53 exiting cooling air 531 is passed through the cavity 56 in the cooling air channels 54.

Between the blade root 521 and the blade receptacle two gaps 551, 552 are formed, each extending between the bottom 523 of the blade root 521 and the Schaufelfußaufnahme. In this case, the one gap 551 extends from the cavity 56 in the direction of the leading edge of the blade root 521 and the other gap 552 from the cavity 56 in the direction of the trailing edge of the blade root 521. In the front view of FIG. 10 Only the gap 551 can be seen, which extends in the direction of the front edge of the blade root 521.

The turbine blade assembly is disposed in the axial direction between non-rotating structures 6, 8 of the gas turbine. Thus, a static structure 6 is located in the axial direction in front of the turbine blade arrangement. The blade arrangement and the static structure 6, for example a vane arrangement or an adjoining part, are in this case through a cavity 71 which extends in the radial direction extends, separated from each other. To reduce the risk that hot gases from the main flow channel 5 penetrate into the cavity 71, a seal 61 which is adjacent to the main flow channel 5 (so-called "rim seal") is provided. If hot gases penetrate through the seal 61 in the cavity 71, there is a risk that such hot gases damage the turbine disk. A sealing mass flow is controlled by a second seal 62 and the leakage or sealing air through the gap between the blade root 521 and Schaufelfußaufnahme.

It should be noted that according to the presentation of the FIG. 2 the cooling air is guided through swirl nozzles 63 into the annular space or the cavity 71. In this case, the cooling air changes from the housing-fixed system into the rotating relative system. The cooling air then flows further into the cooling air holes 53 of the turbine disk 51. The use of swirl nozzles 63 is merely optional.

Correspondingly, a non-rotating structure 8, for example a further vane arrangement, is located in the axial direction behind the turbine blade arrangement, wherein the rotor blade arrangement and the structure 8 are separated from each other by a cavity 72.

The FIG. 3 shows a first embodiment of a turbine blade assembly 50 according to the present invention. Compared to the arrangement of FIG. 2 In addition, a deflection device 31 is provided which partially covers the outlet opening 530 of the window channel 53, ie partially projects beyond it. The deflecting device 51 is provided for this purpose and designed cooling air 531, which emerges from the outlet opening 530, partially divert in the direction of an air passage 551 to increase the driving pressure ratio on this, as shown by the arrow 532.

The air channel 551 is formed in the considered embodiment by the gap which is formed between the underside 523 of the blade root 521 and the Schaufelfußaufnahme, in particular the bottom wall 510 and thereby extends in the axial direction in the direction of the leading edge of the blade root 521. However, it should be noted that, alternatively, a deflection device may also be arranged in such a way that it deflects cooling air in the direction of an air channel 552, which extends in the direction of the trailing edge of the blade root 521. In this respect, the illustrated embodiment is only to be understood as an example.

The deflecting device 31 is concave on its underside 310, which faces the outlet opening 530 of the disk channel 53, with respect to the outlet opening 530. As a result, it absorbs part of the cooling air without great pressure loss and transfers it in a low-loss manner in the direction of the air duct 551 so as to increase the driving pressure ratio. From the air channel 551, the cooling air enters the cavity 71 a. Due to the targeted deflection of a portion of the air by means of the deflection device 31 is in the cooling air passage 551 a compared with that in the FIG. 2 situation presented increased pressure. This increased pressure prevents a potential return flow through the air duct 551 and thus ensures a more reliable supply of the seal 61. This prevents the risk of hot gas entering the cavity 71.

Thus, further functions can be realized via the sealing air provided via the air channel 551. It can be provided as explained that the sealing air according to the arrow 534 of FIG. 3 is used to pressurize the seal 61 with sealing air and thereby prevent hot gases from the main flow channel 5, the seal 61 can pass. If such a function is provided via the compressed air of the cooling air passage 551, the further seal 62 can be simplified.

Another embodiment provides that the sealing air from the air duct 551 is injected obliquely into the cavity 71. For this purpose, the air duct 551 is aligned obliquely to the axial direction, at least in the section which adjoins the cavity 71. The oblique blowing of the cooling air into the cavity leads to an additional acceleration of the blades and to a reduction in the temperature of the cooling air. The exact relationships can be described by the Euler equations.

Further, it can be provided that sealing air is provided in a corresponding manner in the rearwardly extending air duct 552, for example to supply subsequent rows of blades with compressed air, this air can also be used for cooling purposes, such as. a blade cooling.

The FIG. 4 shows an embodiment of a turbine blade assembly 50, wherein the air duct, is deflected in the deflected by the deflection device 31 air, not through the gap 551 between the blade root and Schaufelfußaufnahme, but by an additional passage. Thus, a further air channel 553 is provided. This runs at a radial distance to the bottom 523 of the blade root 521 and ends in an outlet opening 554. The deflection device 31 is arranged deeper in the cavity 56 of the blade root 521 in this embodiment. The position and orientation of the outlet opening 554 can be used to align the sealing air flow emerging from the air duct 553.

The FIG. 11 shows the arrangement of FIG. 4 in a view from the front. The representation largely corresponds to the representation of FIG. 10 , In addition, the air channel 553 is shown, which ends in an outlet opening 554.

The FIG. 4A shows a modification of the embodiment of FIG. 4 , The FIG. 4B shows an enlarged view of the area of the deflection of the FIG. 4A , As with the FIG. 4 will be in the FIGS. 4A . 4B the air duct, in which air is deflected by the deflection device, is not formed by the gap 551 between the blade root and the blade root receiver, but by an additional passage 553, which extends at a radial distance to the underside 523 of the blade root 521 and ends in an outlet opening 554.

The difference to the embodiment of FIG. 4 exists in the position of the deflection device. While in the FIG. 4 the deflection device, the outlet opening 530 of the disc channel 53 partially covered, this is in the FIGS. 4A . 4B not the case. Thus, a deflection device 45 is provided, which does not cover the outlet opening 530, but which is still detected by the divergent emerging from the disc channel 53 air, as shown by the schematically illustrated flow paths of the cooling air 531. In order to divert the divergently emerging from the disk channel 53 air loss, the cooling air facing surface 450 of the deflecting device 45 is concave. In doing so, it continuously merges into the radially outer boundary wall of the air duct 553. Just like in the FIG. 4 the deflection device 45 is disposed relatively deep in the cavity 56 of the blade root 521. The deeper the arrangement in the cavity 56, the more likely the deflecting device 45, despite the lack of an overlap of the outlet opening 530, will still be affected by cooling air and can redirect it accordingly into the air duct 553.

For a better comparison to the embodiment of FIG. 4 is the discharge opening 530 partially overlapping deflecting device 31 of FIG. 4 in the FIGS. 4A . 4B also shown. In a view from above and opposite to the radial direction, the deflection device 31 partially covers the outlet opening 530.

In the sectional view of FIG. 4B is the potential coverage area thereby characterized by the lateral boundaries 91, 92 schematically. The furthest of the outlet opening 530 facing nose 451 of the deflection device 45 is located outside of the coverage area.

In the embodiments of the Figures 3 . 4 . 4A and 4B the deflection device 31, 45 is formed as an integral component of the blade root 521. The deflection device 31, 45 is thus formed in one piece with other components of the rotor blade 52, for example, by a casting process or a cutting process.

The FIG. 5 shows an alternative embodiment of a turbine blade assembly 50, in which the deflection device 31 is formed by a bent sheet, which has been subsequently attached to the underside of the blade root 521, for example by welding or brazing. Also in this embodiment, the deflection device 31 protrudes into the air flow emerging from the disc channel 53 and directs a portion of the air in the direction of an air passage 551, wherein the air passage 551 in the embodiment of FIG. 5 as well as in the embodiment of FIG. 3 is formed by the gap between the blade root 521 and the Schaufelfußaufnahme. However, this is only to be understood as an example. The deflection device 31 has a concave curvature on the underside 310 facing the disk channel 53. However, as will be explained later, this is not necessarily the case and, in the simplest case, the deflecting device may be formed as a planar sheet fastened to the underside 523 of the blade root 521.

It is true for all embodiments that the air ducts can be designed as a nozzle towards its output.

The FIG. 6 shows three embodiments of the deflection, in which the deflection device is formed integrally with the blade root 521 and the blade 52. As illustrated by the diverters 31, 32, 33, the radial distance, the degree of overlap or coverage of the exit opening 530, and the shape of the bottom 310, 320 facing the exit opening 530 may vary. In this case, as illustrated by the deflecting device 33, the underside 330 facing the outlet opening 530 may be planar and in this case extend substantially perpendicular to the flow direction of the cooling air emerging from the outlet opening 530.

The deflection device 31 shows an approximately ideal geometry which is suitable for deflecting cooling air into the cooling air passage 551 with little loss. It forms a gently shaped, continuously in the bottom 532 of the blade root 521 merging boundary surface 310. The deflection device 32 implements a geometry which is advantageous if there is a strong axial clearance between the blade 52 and the turbine disk 51. Since the diverting device 32 is more objectionable in the radial direction from the outlet opening 530, and since the flow emerging from the cooling air hole 53 is divergent, a sufficient part of the cooling air can be diverted into the cooling air passage 551 even if the diverter 32 is less the exit opening 530 covered as in the FIG. 6 shown.

It is further noted that the width of the air channel 551, which is formed by the radial distance between the bottom wall 510 of the Schaufelfußaufnahme and the bottom 523 of the blade root 521, converges towards the leading edge of the blade root. The deflection device 31, 32, 33 is in the FIG. 6 each formed on the underside 532 of the blade root 521.

The FIG. 7 shows three corresponding embodiments of a deflection device 34, 35, 36, which is formed as a separate part and attached to the bottom 532 of the blade root 521. Again, a planar underside 360 or differently configured concave undersides 340, 350 can be realized. It should be noted that the air channel 551 adjacent to the outlet opening 530 of the disk channel 53 is formed radially outwardly by the deflection device 34, 35, 36.

The FIG. 8 shows embodiments of the degree and type of coverage of the outlet opening 530 of a disc channel by a deflection device. In each case, the outlet opening 530 in the turbine disk 51 is shown in a view from above. A deflection device 37, 38, 39 covers the outlet opening 530 in each case partially. The boundary line can, as in the FIG. 8 shown in the view viewed from above have different shapes. In the upper illustration, the boundary line 370 of the deflection device 37 is straight. In the middle illustration, the boundary line 380 of the deflection device 38 to the outlet opening 530 is concave. In the lower illustration, the boundary line 390 of the deflection device 39 to the outlet opening 530 is convex.

The exact shape of the boundary line and the degree of coverage of the exit opening 530 will depend on the boundary conditions. On the one hand, to ensure that the driving pressure ratio in the air duct for the intended functions is sufficiently increased. On the other hand, the cooling function of the blades must not be affected.

As for the FIGS. 6 and 7 explained, the deflection device may have a flat surface in a simple embodiment. This, however, the disadvantage of a rather lower pressure increase is connected. By forming the deflection device by a concave-shaped component significantly more dynamic pressure can be recovered, so that the driving pressure ratio increases more. The FIG. 9 shows exemplary parameters and parameter ratios that allow a low pressure loss. In this case, a resistance coefficient k <0.2 can be realized with regard to the pressure loss at the deflection device.

The embodiment of FIG. 9 shows a deflection device 3, which covers at its farthest the outlet opening 530 of the disk channel 53 projecting boundary line 301, the outlet opening 530 by the length d. The boundary line 301 can, for example, according to the FIG. 8 be educated. The length d decisively determines the proportion of the sealing air, which is deflected into an air duct.

The air channel 55 has a radially outer boundary 523, which is formed by the underside 523 of the blade root 521 or the concave underside 300 of the deflection device 3. It also has a radially inner boundary 510 which is formed by the bottom wall of the blade root receiver of the turbine disk 51. The radially outer boundary 523 is formed at its end, which faces the disc channel 53, through the concave underside 300 of the deflection device 3. It has a radius of curvature r_o there. The radially inner boundary of the air channel 55 has at its end, which faces the disc channel 53, a radius of curvature r_i to the disc channel 53.

It has been found that there are slight pressure losses at the deflecting device 3 when the condition is met that r_m / w> 1, where w is the mean width of the air duct in the region of the deflecting device 3 (averaged from the values w1, w2, w3 of FIG FIG. 9 ) and r_m is the mean value of the two radii of curvature r_o and r_i.

The present invention is not limited in its embodiment to the embodiments described above, which are to be understood merely by way of example. For example, it can alternatively be provided that cooling air is deflected by a deflecting device in the direction of the trailing edge of the blade root. Also, the illustrated proportions and surface curves of the deflection are to be understood as exemplary only.

It should also be understood that the features of each of the described embodiments of the invention may be combined in various combinations. Where ranges are defined, they include all values within those ranges as well as all subranges that fall within an area.

Claims (15)

A turbine blade assembly (50) for a gas turbine, comprising: a turbine disk (51) having at its periphery a plurality of blade root receivers (57), - A turbine blade ring having a plurality of blades (52), each comprising a blade root (521) and which are fixed to the periphery of the turbine disc (51) by the blade roots (521) in the Schaufelfußaufnahmen (57) are arranged , in which - The turbine disk (51) pulley channels (53) for providing air and a pulley channel (53) in each case ends in the region of a Schaufelfußaufnahme (57) in an outlet opening (530), the rotor blades (52) have cooling air ducts (54) for cooling the rotor blades (52), - The pulley channels (53) of the turbine disk (51) and the cooling air channels of the blades (52) are designed and arranged such that air via the pulley channels (53) of the turbine disk (51) the cooling air ducts (54) of the blades (52) is supplied , and - In each case in the blade root (521) or between the blade root (521) and the Schaufelfußaufnahme (57) an air duct (55, 551-553) is formed, exits via the sealing air, which is fed from the disc channel (53), characterized,
the blade root (521) has a deflection device (3, 31-39, 45), which is provided and designed to redirect part of the air emerging from the pulley channel (53) in the direction of the air channel (55, 551-553). Turbine rotor blade assembly according to claim 1, characterized in that the deflection device (3, 31-39, 45) is arranged and designed such that sealing air in the direction of the leading edge of the blade root (521) deflected into the air duct (55, 551, 553) becomes. Turbine rotor blade assembly according to claim 1 or 2, characterized in that the deflection device is arranged and designed such that sealing air in the direction of the trailing edge of the blade root (521) is deflected into the air passage (552). Turbine blade arrangement according to one of the preceding claims, characterized in that the deflection device (33, 36) has a planar surface (330, 360), at which the air emerging from the disc channel (53) is deflected. Turbine blade assembly according to one of claims 1 to 3, characterized in that the deflection device (3, 31, 32, 34, 35, 45) at least in the area which is detected by the air emerging from the disc channel (53), a concave surface (310, 320, 340, 350, 450) which is concave to the disc channel (53). Turbine blade assembly according to claim 5, characterized in that - The air channel (55) has a radially outer boundary and a radially inner boundary whose distance defines the width of the air channel (55), - The radially outer boundary of the air channel (55) at its end, which faces the disc channel (53) is formed by the concave surface and at this has a first, outer radius of curvature r_o, - The radially inner boundary of the air channel (55) at its end, which faces the disc channel (53) has a second, inner radius of curvature r_i, and - the relationship is satisfied that r_m / w> 1, where w is the mean width of the air channel (55) in the region of the deflection device (3, 31-39) and r_m the radius of curvature on the center line between the outer radius of curvature r_o and inner radius of curvature r_i is. Turbine blade assembly according to one of the preceding claims, characterized in that the deflection device (3, 31-39, 45) by a nose-shaped member (451) is formed, the end of which faces the disc channel (53). Turbine blade arrangement according to one of the preceding claims, characterized in that the deflection device (3, 31-39) partially covers the outlet opening (530) of the disc channel (53). Turbine blade arrangement according to claim 8, characterized in that the deflection device (37, 38, 39) in a view from above onto the outlet opening (530) partially covers it along a straight boundary line (370) and / or along an outlet opening (370). 530) concave boundary line (380) partially covered and / or these along a to the outlet opening (530) convex boundary line (390) partially covered. Turbine blade arrangement according to one of the preceding claims, characterized in that the air duct (55, 551, 552), in which by means of the deflecting device (3, 31-39) air is deflected by a between the Schaufelfußaufnahme and the blade root disposed therein (521) is formed in the axial direction extending gap, wherein the deflection device (3, 31-39) on the underside of the blade root (521) is arranged. Turbine blade arrangement according to one of the preceding claims, characterized in that the air duct (553), into which air is deflected by means of the deflecting device (3, 31-39, 45), is formed by a passage extending from a blade root cavity (56 ) to an opening formed in the blade root (521) at the leading edge or at the trailing edge of the blade root (521), the deflection device being formed in the blade root cavity (56). Turbine blade assembly according to one of the preceding claims, characterized in that the deflection device (3, 31-33, 45) is an integral part of the blade root (521). Turbine blade assembly according to one of claims 1 to 11, characterized in that the deflection device (34-36) is a separately manufactured component which has been connected to the underside of the blade root (521). Method for providing sealing air in a turbine blade assembly comprising a turbine disk (51) and a turbine blade ring, wherein air over in the turbine disk (51) formed pulley channels (53), each in the region of a Schaufelfußaufnahme (57) in a Exit port (530) ends, is fed and injected into cooling air passages of the blades (52) of the turbine blade ring,
characterized,
that from the disc channel (53) exiting air by means of a deflecting device (3, 31-39, 45) partially in the direction of an air duct (55, 551-553) is deflected, over which the air as sealing air from the blade root (521) is directed away , Method according to claim 14, characterized in that sealing air emerging from the air duct (551) is led to a seal in the edge region of the main flow duct (5) of the gas turbine between the rotating turbine blade arrangement (50) and an adjoining one, for additional sealing. non-rotating structure (6) is formed.

Images