(19)
(11)EP 2 436 881 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.12.2019 Bulletin 2019/49

(21)Application number: 11177243.0

(22)Date of filing:  11.08.2011
(51)Int. Cl.: 
F01D 11/24  (2006.01)
F01D 5/18  (2006.01)
F01D 9/06  (2006.01)
F01D 11/00  (2006.01)
B60G 21/055  (2006.01)

(54)

Endwall component for a turbine stage of a gas turbine engine

Leitschaufelendwand für einen Gasturbinenmotor

Paroi d'extrémité pour un étage de turbine pour une turbine à gaz


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 29.09.2010 GB 201016335

(43)Date of publication of application:
04.04.2012 Bulletin 2012/14

(73)Proprietor: Rolls-Royce plc
London SW1E 6AT (GB)

(72)Inventor:
  • Tibbott, Ian
    Lichfield, Staffordshire WS14 9XW (GB)

(74)Representative: Rolls-Royce plc 
Intellectual Property Dept SinA-48 PO Box 31
Derby DE24 8BJ
Derby DE24 8BJ (GB)


(56)References cited: : 
JP-A- S60 135 607
US-A1- 2008 118 346
US-A1- 2004 090 013
US-A1- 2008 240 927
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the Invention



    [0001] The present invention relates to a component of a turbine stage of a gas turbine engine, the component forming an endwall for the working gas annulus of the stage.

    Background of the Invention



    [0002] With reference to Figure 1, a ducted fan gas turbine engine generally indicated at 10 has a principal and rotational axis X-X. The engine comprises, in axial flow series, an air intake 11, a propulsive fan 12, an intermediate pressure compressor 13, a high-pressure compressor 14, combustion equipment 15, a high-pressure turbine 16, and intermediate-pressure turbine 17, a low-pressure turbine 18 and a core engine exhaust nozzle 19. A nacelle 21 generally surrounds the engine 10 and defines the intake 11, a bypass duct 22 and a bypass exhaust nozzle 23.

    [0003] The gas turbine engine 10 works in a conventional manner so that air entering the intake 11 is accelerated by the fan 12 to produce two air flows: a first air flow A into the intermediate pressure compressor 14 and a second airflow B which passes through the bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 13 compresses the air flow A directed into it before delivering that air to the high pressure compressor 14 where further compression takes place.

    [0004] The compressed air exhausted from the high-pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 16, 17, 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low-pressure turbines respectively drive the high and intermediate pressure compressors 14, 13 and the fan 12 by suitable interconnecting shafts.

    [0005] The performance of gas turbine engines, whether measured in terms of efficiency or specific output, is improved by increasing the turbine gas temperature. It is therefore desirable to operate the turbines at the highest possible temperatures. For any engine cycle compression ratio or bypass ratio, increasing the turbine entry gas temperature produces more specific thrust (e.g. engine thrust per unit of air mass flow). However as turbine entry temperatures increase, the life of an un-cooled turbine falls, necessitating the development of better materials and the introduction of internal air cooling.

    [0006] In modern engines, the high-pressure turbine gas temperatures are hotter than the melting point of the material of the blades and vanes, necessitating internal air cooling of these airfoil components. During its passage through the engine, the mean temperature of the gas stream decreases as power is extracted. Therefore, the need to cool the static and rotary parts of the engine structure decreases as the gas moves from the high-pressure stage(s), through the intermediate-pressure and low-pressure stages, and towards the exit nozzle.

    [0007] Figure 2 shows an isometric view of a typical single stage cooled turbine. Cooling air flows are indicated by arrows.

    [0008] Internal convection and external films are the prime methods of cooling the gas path components - airfoils, platforms, shrouds and shroud segments etc. High-pressure turbine nozzle guide vanes 31 (NGVs) consume the greatest amount of cooling air on high temperature engines. High-pressure blades 32 typically use about half of the NGV flow. The intermediate-pressure and low-pressure stages downstream of the HP turbine use progressively less cooling air.

    [0009] The high-pressure turbine airfoils are cooled by using high pressure air from the compressor that has by-passed the combustor and is therefore relatively cool compared to the gas temperature. Typical cooling air temperatures are between 800 and 1000 K, while gas temperatures can be in excess of 2100 K.

    [0010] The cooling air from the compressor that is used to cool the hot turbine components is not used fully to extract work from the turbine. Therefore, as extracting coolant flow has an adverse effect on the engine operating efficiency, it is important to use the cooling air effectively.

    [0011] Ever increasing gas temperature levels combined with a drive towards flatter combustion radial profiles, in the interests of reduced combustor emissions, have resulted in an increase in local gas temperature experienced by the working gas annulus endwalls, which include NGV platforms 33, blade platforms 34 and shroud segments 35 (also known as shroud liners). However, the flow of air that is used to cool these endwalls can be highly detrimental to the turbine efficiency. This is due to the high mixing losses attributed to these cooling flows when they are returned to the mainstream working gas path flow.

    [0012] One option is to cool the platforms and shroud segments by an impingement flow of cooling air on the back plane of the gas washed wall of the component. For example, a perforated plate spaced from the gas washed wall and supported by pedestals can form impinging jets, and the spent coolant can then flow back into the working gas path at the rear edges of the component. Unfortunately, limited numbers of impingement jets can produce non uniform heat transfer distributions, and the cross flow from spent coolant can reduce the effectiveness of the impingement jets at the more downstream locations of the component. In addition, the need to keep the coolant pressure at a level above that in the working gas path reduces the allowable pressure drop across the impingement jets, and hence the associated heat transfer levels. Further, most impingement schemes involve brazing or laser welding a sheet metal plate onto a cast component. The drilling of impingement holes into this plate adds cost, and the plate can become detached if the braze or weld cracks in the field due to thermal fatigue

    [0013] Thus, another option is to provide one or more internal cooling passages behind the endwall. Such passages are typically bounded between spaced upper and lower walls that follow the shape of the endwall. US 2004/090013 discloses the preamble of claim 1 and a seal segment for a seal segment ring of a turbine in a gas turbine engine. The seal segment has an inner surface adapted to face the turbine blades in use. Path means are adapted to extend, in use, generally parallel to the principal axis of the turbine and have downstream inlet means through which a cooling fluid to cool the seal segment can enter the path means and upstream outlet means from which the cooling fluid can be exhausted from the path means. US 2008/240927 discloses a turbine blade for a turbine of a thermal power plant, with a platform for partial delimiting of a flow passage in the turbine, wherein the platform has at least one cooling medium passage, which extends inside the platform, for guiding a cooling medium. US2008118346 discloses an air seal unit comprising a main body including a plurality of first impingement cavities and at least one first interconnecting passage extending between and communicating with a first pair of the first impingement cavities. The first interconnecting passage is nonparallel to the first pair of the first impingement cavities and defines a path for cooling air to pass from one impingement cavity of the first pair of the first impingement cavities to another impingement cavity of the first pair of the first impingement cavities so as to strike a wall defining at least a part of the other impingement cavity of the first pair of the first impingement cavities.

    [0014] As shown in Figure 3(a), one arrangement has multi-pass passages 40, optionally augmented with heat transfer augmentation features such as trip strips 41. Another arrangement has a wider passage 42 augmented with e.g. an array of staggered pedestals 43 (Figure 3(b) or parallel fins 44 (Figure 3(c) to increase the wetted plane area of the passage. In Figures 3(a)-(c) the block arrows indicate cooling air flows. Conveniently, such arrangements can usually be formed using single pull die ceramic core technology. However, the arrangements suffer from various limitations. For example, the multi-pass passage arrangement provides a relatively low wetted plane area, the wider passage with a staggered pedestal array also has a relatively low wetted plane area, and the wider passage with parallel fins can suffer from a low level of heat transfer as a boundary layer thickens along the channels formed by the fins. Coolant flow levels therefore have to be increased to offset the low wetted plane area and/or low level of heat transfer. Further, the heat transfer augmentation features can provide unreliable flow distributions, which in turn can lead to unreliable heat transfer coefficients.

    Summary of the Invention



    [0015] An aim of the present invention is to provide internal cooling passages for endwalls that can provide performance benefits over conventional cooling passages.

    [0016] Accordingly, a first aspect of the present invention provides a component of a turbine stage of a gas turbine engine, according to claim 1, the component forming an endwall for the working gas annulus of the stage, and the component having one or more internal passages behind the endwall which, in use, carry a flow of cooling air providing convective cooling for the component at the endwall, wherein:

    each passage is formed by a plurality of straight passage sections which connect in end-to-end series to provide a single flow path such that the connections between nearest-neighbour passage sections form successive 90° angled bends;

    a first portion of the passage sections lies in a first plane, a second portion of the passage sections lies in a second plane which is spaced from and parallel to the first plane, and a third portion of the passage sections extends perpendicularly between the first and the second planes;

    the first plane and the second plane are both spaced from and parallel to a gas washed plane of the endwall;

    the passage sections are either of square, rectangular, or circular cross-section, and the passage follows a convoluted path where each passage section extends parallel to one of three axes, the first and second axes being parallel to the first and second planes, and the third axis being perpendicular to the first and the second planes; and, the passage sections repeat themselves every six passage sections, where every group of three successive end-to-end connected passage sections has one passage section extending along each of the axes; or, the passage sections repeat themselves every eight passage sections, where every group of four successive end-to-end connected passage sections has at least one passage section which extends along each of the axes, with only one passage section in each of these groups extending parallel to the direction of overall extension of the passage.



    [0017] The passages can be adapted to suit most endwall geometries, and can combine high heat transfer coefficients with high wetted plane areas.

    [0018] The component may have any one or, to the extent that they are compatible, any combination of the following optional features.

    [0019] The or each passage can follow a straight overall path or a curved overall path. A straight overall path is typically followed when the gas washed plane of the endwall is flat, and a curved overall path is typically followed when the gas washed plane of the endwall is curved (and the first and the second planes are then also correspondingly curved). In this way, the passage can conform to the endwall, e.g. by maintaining a constant distance behind the endwall.

    [0020] Preferably each passage is formed by at least ten passage sections.

    [0021] The passage sections may have cross-sectional areas in the range from 0.2 to 10 mm2. The lengths of the passage sections may be in the range from 1 to 5 mm.

    [0022] Limiting the possible axes along which the passage sections can extend can simplify the structure of the or each passage, while maintaining adaptability to endwall geometries, and high heat transfer coefficients. By every group of four successive end-to-end connected passage sections having at least one passage section extending along each axis, the passage section repeat distance (which corresponds to the number of passage sections in a characteristic motif for a passage) along the length of the or each passage can be kept short, allowing the passage to have relatively uniform heat transfer characteristics along its length. Indeed, every group of three successive end-to-end connected passage sections can have one passage section extending along each axis.

    [0023] Typically, the three axes are mutually orthogonal. Consistent with this, the connections between nearest-neighbour passage sections can form 90° bends. However, if the axes are not mutually orthogonal, preferably the angle of the bend between any two connected passage sections is not less than about 70°. Smaller bend angles can risk causing excessive pressure drops and flow restrictions in the cooling air.

    [0024] The passage sections of the first portion may extend parallel with the first axis, and the passage sections of the second portion may extend parallel with the second axis. Alternatively, some of the passage sections of the first portion and some of the passage sections of the second portion may extend parallel with the first axis, and the others of the passage sections of the first portion and the others of the passage sections of the second portion may extend parallel with the second axis. In both of these arrangements the first and second axes are thus parallel to the first and second planes. If these planes are curved, then the local directions of the first and second axes are adjusted so that the first and second axes remain parallel to the planes, i.e. the local curvatures of the first and second planes determine the local directions of the first and second axes.

    [0025] The passage sections of the third portion may extend perpendicularly to the first and the second planes. Consistent with this, the passage sections of the third portion can extend parallel with the third axis when the third axis is orthogonal to the first and second axes and the first and second axes are parallel to the first and second planes. Extending the passage sections of the third portion perpendicularly to the first and the second planes facilitates forming the passages from a core that is producable from a single pull die.

    [0026] The passage sections may be equal in length. In another configuration, however, the passage sections of two of the portions may have a first length, and the passage sections of the other portion may have a different second length. In yet another configuration, when each passage section extends parallel to one of the three axes, the passage sections extending parallel to the first axis may have a first length, the passage sections extending parallel to the second axis may have a second length, and the passage sections extending parallel to the third axis may have a third length., the first, second and third lengths all being different from each other.

    [0027] Preferably, the component is a cast component, the passages being formable from a core during the casting of the component, and being configured such that the core is producable from a single pull die. This can reduce the cost of forming the component.

    [0028] Typically, the component has an array of the passages extending in a layer behind the endwall, the layer preferably being parallel to the gas washed plane of the endwall. In this way, the passages can apply cooling across the area of the endwall. Neighbouring passages of the array can be joined in fluid communication with each other, such that cooling air can flow between the passages.

    [0029] In one embodiment, the component can be a shroud segment providing a close clearance to the tips of a row of turbine blades which sweep across the segment. In another embodiment, the component can be a turbine blade, an inner platform of the blade forming the endwall. In yet another embodiment, the component can be a static guide vane, an inner or an outer platform of the vane forming the endwall. Indeed, in the static guide vane embodiment, both the platforms can have one or more of the internal passages.

    Brief Description of the Drawings



    [0030] Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

    Figure 1 shows a schematic longitudinal cross-section through a ducted fan gas turbine engine;

    Figure 2 shows an isometric view of a typical single stage cooled turbine;

    Figures 3(a)-(c) show schematically conventional internal cooling passage arrangements;

    Figure 4 shows schematically a configuration for an internal cooling passage;

    Figure 5 shows schematically a further configuration for an internal cooling passage;

    Figure 6 shows schematically a further configuration for an internal cooling passage;

    Figure 7 shows schematically a further configuration for an internal cooling passage;

    Figure 8 shows schematically a further configuration for an internal cooling passage, which is not part of the claimed invention;

    Figure 9 shows schematically a further configuration for an internal cooling passage;

    Figure 10 shows schematically a further configuration for an internal cooling passage;

    Figure 11 shows schematically a flat array of internal cooling passages; and

    Figure 12 shows schematically a curved array of internal cooling passages.


    Detailed Description



    [0031] Figure 4 shows schematically a configuration for an internal cooling passage that can be located behind the endwall of a component of a turbine stage of a gas turbine engine. In use, cooling air flows along the passage, as indicated by the block arrows, to provide convective cooling of the endwall. The passage is formed from a plurality of short, straight, square-section passage sections 50a, 50b, 50c, which in this example are all of equal length. The passage sections are connected in end-to-end series at successive 90° bends 51.

    [0032] The passage has a direction of overall extension, indicated by the arrow 52. However, only some of the passage sections 50b are parallel with that direction. Other passage sections 50a, 50c extend perpendicular to the direction of overall extension. A first portion 50a of the passage sections lie in a first plane (or surface A, and a second portion 50b of the passage sections lie in a second plane (or surface B. Planes A and B are typically parallel to the gas washed plane of the endwall. A third portion 50c of the passage sections extend perpendicularly to the first and the second planes. The passage sections 50a extend parallel to a first axis X, the passage sections 50b extend parallel to a second axis Y, and the passage sections 50c extend parallel to a third axis Z. Axes X, Y and Z are mutually orthogonal, with axes X and Y being parallel to planes A and B.

    [0033] Every group of four successive end-to-end connected passage sections has at least one passage section which extends along each of the axes, with only one passage section 50b in each of these groups extending parallel to the direction of overall extension. Thus, the passage follows a convoluted path, with many changes of direction. The coolant flow within the passage has to negotiate these changes of direction, and consequently, the flow is continually separating and reattaching within the passage, ensuring that a thin boundary layer is maintained, and that high levels of turbulence occur. As a consequence, high levels of heat transfer can be achieved. However, because the passage sections repeat themselves every eight passage sections (i.e. they have a motif consisting of eight passage sections), the heat transfer characteristics of the passage are fairly uniform along the length of the passage.

    [0034] Figure 5 shows schematically a different configuration for the internal cooling passage. In this configuration, every group of three successive end-to-end connected passage sections has one passage section extending along each of the axes X, Y, Z. The passage sections repeat themselves in this case every six passage sections. Further, the passage sections 50c which extend parallel to the Z axis and perpendicular to the planes A and B in Figure 5 are shorter than the passage sections 50a, 50b, by a ratio of 2:3. Indeed, it is possible for the passage sections to have different lengths depending on which axis they extend along.

    [0035] Figure 6 shows schematically a passage that is similar to that of Figure 5 except that in this case the shorter passage sections 50a lie in the planes A, B and are parallel to axis X. Figure 7 shows schematically yet another passage that is similar to that of Figure 5 except that the passage sections have a rectangular-section rather than a square-section. The rectangular-section provides a larger wetted area than the square-section. If desired, the shape of the cross-section can be changed along the length of the passage, e.g. to enhance heat transfer at specific locations.

    [0036] Other passage configurations are possible, provided they fall within the scope of the claims. Figure 8 shows schematically a configuration for the passage that combines features of the passages of Figures 4 and 5. Figure 9 shows schematically a configuration for the passage in which none of the passage sections are parallel to the direction of overall extension 52 of the passage. The coolant pressure drop per unit length of the passage may be less for the configuration of Figure 9 than for the other passages, as the passage provides fewer changes of direction per unit length.

    [0037] Figure 10 shows schematically a configuration for the passage in which the axes X, Y, Z are not mutually orthogonal. In this case, axis Z is perpendicular to axes X, Y, but axis X is angled at about 45° to axis Y. Nonetheless, as each passage section 50a extending parallel to axis X connects at both ends to passage sections 50c extending parallel to axis Z, the cooling air flowing into and out of each passage section 50a turns through 90° bends, which do not lead to excessive pressure drops in the cooling air. In general, to avoid excessive pressure drops, the angle of the bend between any two connected passage sections is preferably not less than about 70°.

    [0038] The endwall can have an array of the passages extending in a layer behind the wall. Figure 11 shows schematically such an array which is flat, based in this case on side-by-side passages having the configuration of Figure 5. However, if the gas-washed plane of the endwall is curved, then conveniently the individual passages and the array as a whole can be curved to conform with the shape of that plane, as shown in Figure 12 which is a curved array of passages having the configuration of Figure 5. In Figure 12, the passage sections 50a still extend parallel to the first axis X, the passage sections 50b still extend parallel to the second axis Y, and the passage sections 50c still extend parallel to a third axis Z. However, as the planes A and B are curved to match the curvature of the gas washed plane, the direction of the axes X, Y and Z at any point are determined relative to the tangent plane to plane A or B at that point.

    [0039] In Figures 11 and 12, no links are shown connecting the passages of each array. In practice, however, it can be advantageous to form links between neighbouring passages so that coolant can flow between the passages. This can allow any dirt or debris blockages in the passages to be circumvented, and can help to equalise coolant pressures across the passages. The links can also strengthen the cores (discussed below) from which the passages can be formed.

    [0040] The component can have one or more reservoirs from which to feed cooling air to the passages. The reservoir(s) can have a dual role supplying cooling air onto the gas washed plane of the endwall through a series of film cooling holes as well as supplying cooling air to the passages. In general, the coolant supplied to the passages is required to have a relatively high pressure ratio because the numerous bends cause significant pressure losses.

    [0041] In typical applications, the passage sections may have cross-sectional areas in the range from 0.2 to 10 mm2. The lengths of the passage sections may be in the range from 1 to 5 mm.

    [0042] The configurations discussed above can be manufactured using single pull die ceramic core technology, as used for conventional passages augmented with pedestals, pin-fins, trip strips etc. In particular, having the passage sections 50c extend perpendicularly to the planes A, B and the gas-washed plane of the endwall facilitates the use of this technology. There is, therefore, no need for costly multiple slide dies or soluble core technologies. However, these advanced casting technologies may allow more diverse passage shapes to be achieved. Individual passages can be produced separately. Alternatively an array of passages can be produced with common entries or exits, or arrays of passages can be produced connected at designated locations to neighbouring passages.

    [0043] Advantageously, the passage configurations facilitate the formation of a compact internal heat exchanger arrangement which can be adapted to suit almost any endwall geometry. These heat exchangers have the ability to deliver high levels of heat transfer with increased wetted plane area in locations of the turbine where adequate pressure drop to drive the cooling flow is available. They can be configured in single or multiple arrays and can be made to conform to most curved planes and shapes. They can be manufactured using ceramic cores produced from conventional single pull dies and are therefore a cost effective alternative to impingement and pedestal arrays.

    [0044] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the claims.


    Claims

    1. A component of a turbine stage of a gas turbine engine, the component forming an endwall for the working gas annulus of the stage, and the component having one or more internal passages behind the endwall which, in use, carry a flow of cooling air providing convective cooling for the component at the endwall, wherein:

    each passage is formed by a plurality of straight passage sections (50a, 50b, 50c) which connect in end-to-end series to provide a single flow path such that the connections between nearest-neighbour passage sections form successive 90° angled bends (51);

    a first portion (50a) of the passage sections lies in a first plane (A), a second portion of the passage sections lies in a second plane (B) which is spaced from and parallel to the first plane, and a third portion (50c) of the passage sections extends perpendicularly between the first and the second planes;

    the first plane (A) and the second plane (B) are both spaced from and parallel to a gas washed plane of the endwall;

    the passage sections (50a, 50b, 50c) are either of square, rectangular, or circular cross-section, and the passage follows a convoluted path where each passage section extends parallel to one of three axes (X, Y, Z), the first and second axes (X, Y) being parallel to the first and second planes, and the third axis (Z) being perpendicular to the first and the second planes; and,

    characterised in that the passage sections repeat themselves every six passage sections, where every group of three successive end-to-end connected passage sections has one passage section extending along each of the axes; or in that

    the passage sections repeat themselves every eight passage sections, where every group of four successive end-to-end connected passage sections has at least one passage section which extends along each of the axes, with only one passage section in each of these groups extending parallel to the direction of overall extension (52) of the passage.


     
    2. A component according to claim 1, wherein the axes are mutually orthogonal.
     
    3. A component according to any one of the previous claim, wherein the passage sections of the first portion (50a) extend parallel to the first axis, and the passage sections of the second portion (50b) extend parallel to the second axis.
     
    4. A component according to claim 1 or claim 2, wherein some of the passage sections of the first portion and some of the passage sections of the second portion extend parallel to the first axis, and the others of the passage sections of the first portion and the others of the passage sections of the second portion extend parallel to the second axis.
     
    5. A component according to any one of the previous claims, wherein the passage sections of the third portion (50c) extend perpendicularly to the first and the second planes.
     
    6. A component according to any one of the previous claims, wherein each passage is formed by at least ten passage sections.
     
    7. A component according to any one of the previous claims, wherein the passage sections are equal in length.
     
    8. A component according to any one of the previous claims, which is a cast component, the passages being formable from a core during the casting of the component, and being configured such that the core is producable from a single pull die.
     
    9. A component according to any one of the previous claims, having an array of the passages extending in a layer behind the endwall.
     
    10. A component according to claim 9, wherein neighbouring passages of the array are joined in fluid communication with each other.
     
    11. A component according to any one of the previous claims, which is a shroud segment providing a close clearance to the tips of a row of turbine blades which sweep across the segment.
     
    12. A component according to any one of claims 1 to 10, which is a turbine blade, an inner platform of the blade forming the endwall.
     
    13. A component according to any one of claims 1 to 10, which is a static guide vane, an inner or an outer platform of the vane forming the endwall.
     


    Ansprüche

    1. Komponente einer Turbinenstufe eines Gasturbinentriebwerks, wobei die Komponente eine Endwand für den Arbeitsgasring der Stufe bildet und die Komponente einen oder mehrere interne Durchgänge hinter der Endwand aufweist, die während der Verwendung einen Strom von Kühlluft führen, der konvektive Kühlung für die Komponente an der Endwand bereitstellt, wobei:

    jeder Durchgang durch eine Vielzahl von geraden Durchgangsabschnitten (50a, 50b, 50c) gebildet wird, die durchgehend in Reihe verbunden sind, um einen einzelnen Strömungspfad bereitzustellen, sodass die Verbindungen zwischen nächstgelegenen Durchgangsabschnitten aufeinanderfolgende, um 90°abgewinkelte Biegungen (51) bilden;

    ein erster Abschnitt (50a) der Durchgangsabschnitte in einer ersten Ebene (A) liegt, ein zweiter Abschnitt der Durchgangsabschnitte in einer zweiten Ebene (B) liegt, die von der ersten Ebene beabstandet und zu dieser parallel ist, und ein dritter Abschnitt (50c) der Durchgangsabschnitte sich senkrecht zwischen der ersten und der zweite Ebene erstreckt;

    die erste Ebene (A) und die zweite Ebene (B) beide von einer gasgewaschenen Ebene der Endwand beabstandet und zu dieser parallel sind;

    die Durchgangsabschnitte (50a, 50b, 50c) entweder einen quadratischen, rechteckigen oder kreisförmigen Querschnitt aufweisen und der Durchgang einem gewundenen Pfad folgt, wo jeder Durchgangsabschnitt sich parallel zu einer von drei Achsen (X, Y, Z) erstreckt, wobei die erste und die zweite Achse (X, Y) parallel zu der ersten und der zweiten Ebene sind, und die dritte Achse (Z) senkrecht zu der ersten und der zweiten Ebene ist;

    und dadurch gekennzeichnet, dass die Durchgangsabschnitte sich alle sechs Durchgangsabschnitte wiederholen, wobei jede Gruppe von drei aufeinanderfolgenden, durchgehend verbundenen Durchgangsabschnitten einen Durchgangsabschnitt aufweist, der sich entlang jeder von den Achsen erstreckt;

    oder dadurch, dass die Durchgangsabschnitte sich alle acht Durchgangsabschnitte wiederholen, wobei jede Gruppe von vier aufeinanderfolgenden, durchgehend verbundenen Durchgangsabschnitten mindestens einen Durchgangsabschnitt aufweist, der sich entlang jeder von den Achsen erstreckt, wobei nur ein Durchgangsabschnitt in jeder von diesen Gruppen sich parallel zu der Richtung der Gesamterstreckung (52) des Durchgangs erstreckt.


     
    2. Komponente nach Anspruch 1, wobei die Achsen zueinander orthogonal sind.
     
    3. Komponente nach einem der vorhergehenden Ansprüche, wobei die Durchgangsabschnitte des ersten Abschnitts (50a) sich parallel zu der ersten Achse erstrecken, und die Durchgangsabschnitte des zweiten Abschnitts (50b) sich parallel zu der zweiten Achse erstrecken.
     
    4. Komponente nach Anspruch 1 oder Anspruch 2, wobei einige der Durchgangsabschnitte des ersten Abschnitts und einige der Durchgangsabschnitte des zweiten Abschnitts sich parallel zu der ersten Achse erstrecken, und die anderen der Durchgangsabschnitte des ersten Abschnitts und die anderen der Durchgangsabschnitte des zweiten Abschnitts sich parallel zu der zweiten Achse erstrecken.
     
    5. Komponente nach einem der vorhergehenden Ansprüche, wobei die Durchgangsabschnitte des dritten Abschnitts (50c) sich senkrecht zu der ersten und der zweiten Ebene erstrecken.
     
    6. Komponente nach einem der vorhergehenden Ansprüche, wobei jeder Durchgang durch mindestens zehn Durchgangsabschnitte gebildet wird.
     
    7. Komponente nach einem der vorhergehenden Ansprüche, wobei die Durchgangsabschnitte gleich lang sind.
     
    8. Komponente nach einem der vorhergehenden Ansprüche, bei der es sich um eine gegossene Komponente handelt, wobei die Durchgänge während des Gießens der Komponente aus einem Kern formbar sind und derart ausgelegt sind, dass der Kern aus einer einzelnen Zugform herstellbar ist.
     
    9. Komponente nach einem der vorhergehenden Ansprüche, die eine Anordnung der Durchgänge aufweist, die sich in einer Schicht hinter der Endwand erstreckt.
     
    10. Komponente nach Anspruch 9, wobei benachbarte Durchgänge der Anordnung in Fluidverbindung miteinander verbunden sind.
     
    11. Komponente nach einem der vorhergehenden Ansprüche, bei der es sich um ein Mantelsegment handelt, das einen engen Abstand zu den Spitzen einer Reihe von Turbinenschaufeln bereitstellt, die über das Segment streifen.
     
    12. Komponente nach einem der Ansprüche 1 bis 10, bei der es sich um eine Turbinenschaufel handelt, wobei eine innere Plattform der Schaufel die Endwand bildet.
     
    13. Komponente nach einem der Ansprüche 1 bis 10, bei der es sich um eine statische Leitschaufel handelt, wobei eine innere oder eine äußere Plattform der Schaufel die Endwand bildet.
     


    Revendications

    1. Composant d'un étage de turbine d'un moteur à turbine à gaz, le composant formant une paroi d'extrémité pour l'anneau de gaz de travail de l'étage, et le composant comportant un ou plusieurs passages internes derrière la paroi d'extrémité qui, lors de l'utilisation, acheminent un flux d'air de refroidissement assurant un refroidissement par convection pour le composant au niveau de la paroi d'extrémité,
    chaque passage étant formé par une pluralité de sections de passage rectilignes (50a, 50b, 50c) qui se raccordent en série bout à bout pour obtenir un seul chemin d'écoulement de sorte que les raccords entre les sections de passage voisines les plus proches forment des courbures (51) successives inclinées à 90° ;
    une première partie (50a) des sections de passage se trouvant dans un premier plan (A), une deuxième partie des sections de passage se trouvant dans un second plan (B) qui est espacé du premier plan et parallèle à celui-ci, et une troisième partie (50c) des sections de passage s'étendant perpendiculairement entre les premier et second plans ;
    ledit premier plan (A) et ledit second plan (B) étant à la fois espacés d'un plan lavé au gaz de la paroi d'extrémité et parallèles à celui-ci ;
    lesdits sections de passage (50a, 50b, 50c) étant des section transversales carrées, rectangulaires ou circulaires, et ledit passage suivant un chemin sinueux où chaque section de passage s'étend parallèlement à l'un des trois axes (X, Y, Z), lesdits premier et deuxième axes (X, Y) étant parallèles aux premier et second plans, et ledit troisième axe (Z) étant perpendiculaire aux premier et second plans ;
    et caractérisé en ce que les sections de passage se répètent toutes les six sections de passage, chaque groupe de trois sections de passage successives raccordées bout à bout possédant une section de passage s'étendant le long de chacun des axes ;
    ou en ce que les sections de passage se répètent toutes les huit sections de passage, chaque groupe de quatre sections de passage successives raccordées bout à bout possédant au moins une section de passage s'étendant le long de chacun des axes, avec uniquement une section de passage dans chacun de ces groupes qui s'étend parallèlement à la direction d'extension globale (52) du passage.
     
    2. Composant selon la revendication 1, lesdits axes étant orthogonaux entre eux.
     
    3. Composant selon l'une quelconque des revendications précédentes, lesdites sections de passage de la première partie (50a) s'étendant parallèlement au premier axe et lesdites sections de passage de la deuxième partie (50b) s'étendant parallèlement au deuxième axe.
     
    4. Composant selon la revendication 1 ou 2, certaines des sections de passage de la première partie et certaines des sections de passage de la deuxième partie s'étendant parallèlement au premier axe, et lesdites autres sections des sections de passage de la première partie et lesdites autres sections des sections de passage de la deuxième partie s'étendant parallèlement au deuxième axe.
     
    5. Composant selon l'une quelconque des revendications précédentes, lesdites sections de passage de la troisième partie (50c) s'étendant perpendiculairement aux premier et second plans.
     
    6. Composant selon l'une quelconque des revendications précédentes, chaque passage étant formé d'au moins dix sections de passage.
     
    7. Composant selon l'une quelconque des revendications précédentes, lesdites sections de passage étant de longueur égale.
     
    8. Composant selon l'une quelconque des revendications précédentes, qui est un composant moulé, les passages pouvant être formés à partir d'un noyau durant le moulage du composant et étant conçus de sorte que le noyau puisse être produit à partir d'une seule matrice de traction.
     
    9. Composant selon l'une quelconque des revendications précédentes, comportant un réseau de passages s'étendant dans une couche derrière la paroi d'extrémité.
     
    10. Composant selon la revendication 9, lesdits passages voisins du réseau étant reliés en communication fluidique les uns aux autres.
     
    11. Composant selon l'une quelconque des revendications précédentes, qui est un segment de carénage offrant un jeu étroit aux extrémités d'une rangée d'aubes de turbine qui balayent le segment.
     
    12. Composant selon l'une quelconque des revendications 1 à 10, qui est une aube de turbine, une plate-forme interne de l'aube formant la paroi d'extrémité.
     
    13. Composant selon l'une quelconque des revendications 1 à 10, qui est une aube directrice statique, une plate-forme interne ou externe de l'aube formant la paroi d'extrémité.
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description