(19)
(11)EP 2 885 504 B1

(12)EUROPEAN PATENT SPECIFICATION

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

(21)Application number: 13846039.9

(22)Date of filing:  15.07.2013
(51)International Patent Classification (IPC): 
F01D 5/20(2006.01)
(86)International application number:
PCT/US2013/050429
(87)International publication number:
WO 2014/058493 (17.04.2014 Gazette  2014/16)

(54)

AIRFOIL AND CORRESPONDING GAS TURBINE ENGINE

SCHAUFEL UND ZUGEHÖRIGES GASTURBINENTRIEBWERK

AUBE ET MOTEUR À TURBINE À GAZ ASSOCIÉ


(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: 15.08.2012 US 201213586071

(43)Date of publication of application:
24.06.2015 Bulletin 2015/26

(73)Proprietor: United Technologies Corporation
Farmington, CT 06032 (US)

(72)Inventors:
  • CHLUS, Wieslaw A.
    Wethersfield, Connecticut 06109 (US)
  • THOMEN, Seth J.
    Colchester, Connecticut 06415 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
EP-A1- 2 434 097
US-A1- 2003 021 684
US-A1- 2008 118 367
US-A1- 2009 092 500
US-B1- 8 061 987
US-A1- 2003 021 684
US-A1- 2004 096 328
US-A1- 2009 092 500
US-A1- 2012 070 308
  
      
    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

    BACKGROUND



    [0001] This disclosure relates to an airfoil having a tip cooling features for use in, for example, an industrial gas turbine engine.

    [0002] Industrial gas turbine blades may experience tip burning due to the increased temperatures at the airfoil tip, especially on first stage turbine blades. Tips are often cooled with internal core cooling air that is released through radial holes on the surface of a tip pocket, which is provided between pressure and suction walls. These cooling holes are provided in an end wall that joins the pressure and suction walls and are spaced inwardly from the pressure and suction walls at the interior of the pocket. The cooling holes pressurize the pocket to resist hot gas path air from flowing into the pocket and oxidizing the tip material. Much of the cooling air is mixed with hot gas path air and lost in the flow of the gas path.

    [0003] EP 2434097 A1 describes a turbine blade.

    [0004] US 8061987 B1 describes a turbine blade with a squealer pocket formed by a tip rail to provide tip rail cooling, according to the preamble of claim 1.

    [0005] US 2003/0021684 A1 describes a gas turbine blade tip cooling construction.

    [0006] US 2009/0092500 A1 describes a hollow turbomachine blade including an internal cooling passage.

    SUMMARY



    [0007] The invention is defined in the accompanying claims.

    [0008] In one exemplary embodiment, an airfoil for a gas turbine engine includes pressure and suction walls spaced apart from one another and joined at leading and trailing edges to provide an airfoil that extends in a radial direction. The airfoil has a cooling passage arranged between the pressure and suction walls that extend toward a tip of the airfoil. The tip includes a pocket that separates the pressure and suction walls. Scarfed cooling holes fluidly connect the cooling passage to the pocket. The scarfed cooling holes include a portion that is recessed into a face of the suction wall and exposed to the pocket.

    [0009] In a further embodiment of any of the above, the suction wall terminates in a suction side edge at the tip. The scarfed cooling holes extend to the suction side edge.

    [0010] In a further embodiment of any of the above, the scarfed cooling holes include a semi-circular cross-section.

    [0011] In a further embodiment of any of the above, the scarfed cooling holes are at an angle relative to the radial direction.

    [0012] In a further embodiment of any of the above, the pressure wall has a notch at the trailing edge.

    [0013] In a further embodiment of any of the above, the airfoil includes an end wall joining the pressure and suction walls at the pocket. The scarfed cooling holes extend through the end wall.

    [0014] In a further embodiment of any of the above, the airfoil includes other cooling holes that extend through the end wall and are spaced from the pressure and suction walls.

    [0015] In a further embodiment of any of the above, the scarfed cooling holes include a non-semi-circular cross-section.

    [0016] In a further embodiment of any of the above, the suction wall terminates in a suction side edge at the tip. The scarfed cooling holes include a neck portion adjoining a diffuser portion. The diffuser portion terminates at the suction side edge.

    [0017] In a further embodiment of any of the above, the airfoil is a turbine blade.

    [0018] In another exemplary embodiment, a gas turbine engine includes a compressor and turbine section mounted to a shaft, and a combustor arranged between the compressor and turbine section. The gas turbine engine includes an airfoil in one of the compressor and turbine sections. The airfoil includes pressure and suction walls spaced apart from one another and joined at leading and trailing edges to provide an airfoil that extends in a radial direction. The airfoil has a cooling passage arranged between the pressure and suction walls that extend toward a tip of the airfoil. The tip includes a pocket separating the pressure and suction walls, and scarfed cooling holes fluidly connect the cooling passage to the pocket. The scarfed cooling holes include a portion that is recessed into a face of the suction wall and exposed to the pocket.

    [0019] In a further embodiment of any of the above, the airfoil is a blade in the turbine section.

    [0020] In a further embodiment of any of the above, the gas turbine engine includes a power turbine that is downstream from the turbine section. The power turbine is coupled to a generator configured to supply power to a power grid.

    [0021] In a further embodiment of any of the above, the suction wall terminates in a suction side edge at the tip. The scarfed cooling holes extend to the suction side edge. The pressure wall has a notch at the trailing edge.

    [0022] In a further embodiment of any of the above, the scarfed cooling holes are at an angle relative to the radial direction and near the notch.

    [0023] In a further embodiment of any of the above, the gas turbine engine includes an end wall joining the pressure and suction walls at the pocket. The scarfed cooling holes extending through the end wall.

    [0024] In a further embodiment of any of the above, the gas turbine engine includes other cooling holes extending through the end wall and spaced from the pressure and suction walls.

    [0025] In a further embodiment of any of the above, the scarfed cooling holes include a semi-circular cross-section.

    [0026] In a further embodiment of any of the above, suction wall terminates in a suction side edge at the tip. The scarfed cooling holes include a neck portion adjoining a diffuser portion. The diffuser portion terminates at the suction side edge.

    [0027] In another exemplary embodiment, an airfoil for a gas turbine engine includes pressure and suction walls spaced apart from one another and joined at leading and trailing edges to provide an airfoil that extends in a radial direction. The airfoil has a cooling passage arranged between the pressure and suction walls that extend toward a tip of the airfoil. The tip includes a pocket separating the pressure and suction walls. Scarfed cooling holes fluidly connect the cooling passage to the pocket. The scarfed cooling holes include a portion recessed into a face of one of the pressure and suction walls and exposed to the pocket.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0028] The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

    Figure 1 is a schematic cross-sectional view of an example industrial gas turbine engine.

    Figure 2 is a perspective view of an example airfoil including one example disclosed tip cooling configuration.

    Figure 3 is a perspective view of a scarfed cooling hole arrangement in the airfoil tip.

    Figure 4 is a cross-sectional view of the airfoil shown in Figure 3 taken along line 4-4.

    Figure 5 is another perspective view of a scarfed cooling hole arrangement in the airfoil tip.

    Figure 6 is an enlarged cross-sectional view of a scarfed cooling hole shown in Figure 5.


    DETAILED DESCRIPTION



    [0029] A schematic view of an industrial gas turbine engine 10 is illustrated in Figure 1. The engine 10 includes a compressor section 12 and a turbine section 14 interconnected to one another by a shaft 16. A combustor 18 is arranged between the compressor and turbine sections 12, 14. A power turbine 20 is arranged downstream from the turbine section 14. The power turbine 20 rotationally drives a generator 22, which is connected to a power grid 23. It should be understood that the illustrated engine 10 is highly schematic, and may vary from the configuration illustrated. Moreover, the disclosed airfoil may be used in commercial and military aircraft engines as well as industrial gas turbine engines.

    [0030] The turbine section 14 includes multiple turbine blades, one of which is illustrated at 24 in Figure 2. The turbine blade 24 includes a root 26 configured to be supported by a rotor mounted to the shaft 16. A platform 28 is mounted on the root 26, and an airfoil 30 extends in a radial direction R from the platform 28 to a tip 32.

    [0031] Referring to Figures 2 and 3, the airfoil 30 is provided by spaced apart pressure and suction walls 38, 40 that are joined to one another at leading and trailing edges 34, 36. The tip 32 includes a pocket 42 that receives cooling fluid from a cooling passage 44 (shown in Figure 4) arranged within the airfoil 30 between the pressure and suction walls 38, 40, as best shown in Figure 4. A notch 46 arranged near the trailing edge 36 permits the cooling fluid to flow from the pocket 42 near the trailing edge 36, as best illustrated in Figure 3.

    [0032] An end wall 43 joins the pressure and suction walls 38, 40 beneath the pocket 42. Cooling holes 48 may extend through the end wall 43 to fluidly connect the pocket 42 to the cooling passage 44. A first set of scarfed cooling holes 50 fluidly interconnect the cooling passage 44 to the pocket 42. A portion 53 of the scarfed cooling holes 50 are recessed into a face 51 of the suction wall 40 within the pocket 42, best shown in Figure 4. The recessed portion 53 provides a channel extending a radial length 55 in the radial direction R. The scarfed cooling holes 50 extend to the suction side edge 54. The suction side edge 54 and a pressure side edge 52 are adjacent to a blade outer air seal (not shown).

    [0033] In the examples illustrated in Figures 3 and 4, the scarfed cooling holes 50, in particular, the recessed portion 53, provide a semi-circular cross-section. A second set of scarfed cooling holes 56 are arranged in the pocket 42 adjacent to the notch 46. In this region, the second set of scarfed cooling holes 56 is oriented differently than the first scarfed holes 50 and at an angle relative to the radial direction R.

    [0034] The scarfed cooling holes 50, 56 may be drilled or otherwise provided. The scarfed configuration enables cooling air to be entrained within the channels, which improves heat transfer and cooling of the suction wall 40. Entraining the cooling air helps resist the cooling air from being washed out of the tip pocket by gases G from the gas flow path flowing past the pressure side edge 52 into the pocket 42. As a result, the potential for tip burning is reduced.

    [0035] The scarfed cooling holes/channels could be round or shaped, perpendicular or angled to the face of the pocket 42. Scarfed cooling holes 150, 156 may be provided having a different shape, as best illustrated in Figures 5 and 6. The scarfed holes 150 in the suction wall 140 include a neck portion 58 and a diffuser portion 60, which extends to the suction side edge 154 of the tip 132. The neck portion 60 extends through the end wall 143.

    [0036] Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.


    Claims

    1. An airfoil (30) for a gas turbine engine comprising:

    pressure and suction walls (38, 40; 140) spaced apart from one another and joined at leading and trailing edges (34, 36) to provide an airfoil (30) that extends in a radial direction, the airfoil (30) having a cooling passage (44) arranged between the pressure and suction walls (38, 40; 140) that extends toward a tip (32) of the airfoil (30), the tip (32) including a pocket (42) separating the pressure and suction walls (38, 40); and

    scarfed cooling holes (50; 150) fluidly connecting the cooling passage (44) to the pocket (42), the scarfed cooling holes (50; 150) including a portion (53) recessed into a face of one of the pressure wall (38) and suction wall (40; 140) and exposed to the pocket (42) and wherein the pressure wall has a notch (46) at the trailing edge (36) that is in fluid communication with the pocket (42),

    characterized in that the scarfed cooling holes (50; 150) include a first set of scarfed cooling holes (50; 150) and a second set of scarfed cooling holes (56; 156) arranged in the pocket (42) adjacent to the notch (46) that are oriented differently than the first set of scarfed cooling holes (50; 150) and at an angle relative to the radial direction.


     
    2. The airfoil according to claim 1, wherein the portion (53) is recessed into a face of the suction wall (40; 140).
     
    3. The airfoil according to claim 2, wherein the suction wall (40; 140) terminates in a suction side edge (54; 154) at the tip (32; 132); the scarfed cooling holes (50; 150) extending to the suction side edge (54; 154).
     
    4. The airfoil according to claim 2 or 3, wherein the scarfed cooling holes (50; 150) are at an angle relative to the radial direction.
     
    5. The airfoil according to any of claims 2 to 4, comprising an end wall (43; 143) joining the pressure and suction walls (38; 40; 140) at the pocket (42), the scarfed cooling holes (50; 150) extending through the end wall (43; 143).
     
    6. The airfoil according to claim 5, comprising other cooling holes (48) extending through the end wall (43; 143) and spaced from the pressure and suction walls (38, 40; 140).
     
    7. The airfoil according to any of claims 2 to 6, wherein the scarfed cooling holes (50; 150) include a semi-circular cross-section.
     
    8. The airfoil according to any of claims 2 to 6, wherein the scarfed cooling holes (150) include a non-semi-circular cross-section.
     
    9. The airfoil according to claim 8, wherein the suction wall (140) terminates in a suction side edge (154) at the tip (132), and the scarfed cooling holes (150) include a neck portion (58) adjoining a diffuser portion (60), the diffuser portion (60) terminating at the suction side edge (154).
     
    10. The airfoil according to any of claims 2 to 9, wherein the airfoil (30) is a turbine blade.
     
    11. A gas turbine engine (10) comprising:

    a compressor (12) and turbine section (14) mounted to a shaft (16), and a combustor (18) arranged between the compressor (12) and turbine section (14); and

    an airfoil (30) in one of the compressor and turbine sections (12, 14), the airfoil (30) being an airfoil according to any of claims 2 to 10.


     
    12. The gas turbine engine according to claim 11, wherein the airfoil (30) is a blade in the turbine section (14).
     
    13. The gas turbine engine according to claim 11 or 12, comprising a power turbine (20) downstream from the turbine section (14), the power turbine (20) coupled to a generator (22) configured to supply power to a power grid (23).
     


    Ansprüche

    1. Schaufel (30) für ein Gasturbinentriebwerk, umfassend:

    eine Druck- und eine Saugwand (38, 40; 140), die voneinander beabstandet und an einer Vorder- und einer Hinterkante (34, 36) verbunden sind, um eine Schaufel (30) bereitzustellen, die sich in einer radialen Richtung erstreckt, wobei die Schaufel (30) einen Kühldurchlass (44) aufweist, der zwischen der Druck- und der Saugwand (38, 40; 140) angeordnet ist, der sich in Richtung einer Spitze (32) der Schaufel (30) erstreckt, wobei die Spitze (32) eine Tasche (42) beinhaltet, die die Druck- und die Saugwand (38, 40) trennt; und

    zurückgeschnittene Kühllöcher (50; 150), die den Kühldurchlass (44) fluidisch mit der Tasche (42) verbinden, wobei die zurückgeschnittenen Kühllöcher (50; 150) einen Abschnitt (53) beinhalten, der in eine Fläche von einer von der Druckwand (38) und der Saugwand (40; 140) ausgespart und gegenüber der Tasche (42) exponiert ist, und wobei die Druckwand eine Kerbe (46) an der Hinterkante (36) aufweist, die in Fluidkommunikation mit der Tasche (42) steht,

    dadurch gekennzeichnet, dass die zurückgeschnittenen Kühllöcher (50; 150) einen ersten Satz an zurückgeschnittenen Kühllöchern (50; 150) und einen zweiten Satz an zurückgeschnittenen Kühllöchern (56; 156) angeordnet in der Tasche (42) benachbart zu der Kerbe (46) beinhalten, die anders als der erste Satz an zurückgeschnittenen Kühllöchern (50; 150) und in einem Winkel relativ zu der radialen Richtung ausgerichtet sind.


     
    2. Schaufel nach Anspruch 1, wobei der Abschnitt (53) in eine Fläche der Saugwand (40; 140) ausgespart ist.
     
    3. Schaufel nach Anspruch 2, wobei die Saugwand (40; 140) in einer Saugseitenkante (54; 154) an der Spitze (32; 132) endet; wobei sich die zurückgeschnittenen Kühllöcher (50; 150) zu der Saugseitenkante (54; 154) erstrecken.
     
    4. Schaufel nach Anspruch 2 oder 3, wobei die zurückgeschnittenen Kühllöcher (50; 150) in einem Winkel relativ zu der radialen Richtung sind.
     
    5. Schaufel nach einem der Ansprüche 2 bis 4, umfassend eine Stirnwand (43; 143), die die Druck- und die Saugseitenwand (38; 40; 140) an der Tasche (42) verbindet, wobei sich die zurückgeschnittenen Kühllöcher (50; 150) durch die Stirnwand (43; 143) erstrecken.
     
    6. Schaufel nach Anspruch 5, umfassend andere Kühllöcher (48), die sich durch die Stirnwand (43; 143) erstrecken und von der Druck- und der Saugwand (38, 40; 140) beabstandet sind.
     
    7. Schaufel nach einem der Ansprüche 2 bis 6, wobei die zurückgeschnittenen Kühllöcher (50; 150) einen halbkreisförmigen Querschnitt beinhalten.
     
    8. Schaufel nach einem der Ansprüche 2 bis 6, wobei die zurückgeschnittenen Kühllöcher (150) einen nichthalbkreisförmigen Querschnitt beinhalten.
     
    9. Schaufel nach Anspruch 8, wobei die Saugwand (140) in einer Saugseitenkante (154) an der Spitze (132) endet und die zurückgeschnittenen Kühllöcher (150) einen Halsabschnitt (58) beinhalten, der sich einem Diffusorabschnitt (60) anschließt, wobei der Diffusorabschnitt (60) an der Saugseitenkante (154) endet.
     
    10. Schaufel nach einem der Ansprüche 2 bis 9, wobei die Schaufel (30) eine Turbinenschaufel ist.
     
    11. Gasturbinentriebwerk (10), umfassend:

    einen Verdichterabschnitt (12) und einen Turbinenabschnitt (14), die an einer Welle (16) montiert sind, und eine Brennkammer (18), die zwischen dem Verdichterabschnitt (12) und dem Turbinenabschnitt (14) angeordnet ist; und

    eine Schaufel (30) in einem von dem Verdichterabschnitt und dem Turbinenabschnitt (12, 14), wobei die Schaufel (30) eine Schaufel nach einem der Ansprüche 2 bis 10 ist.


     
    12. Gasturbinentriebwerk nach Anspruch 11, wobei die Schaufel (30) eine Laufschaufel in dem Turbinenabschnitt (14) ist.
     
    13. Gasturbinentriebwerk nach Anspruch 11 oder 12, umfassend eine Leistungsturbine (20) stromabwärts des Turbinenabschnitts (14), wobei die Leistungsturbine (20) an einen Generator (22) gekoppelt ist, der konfiguriert ist, um einem Leistungsnetz (23) Leistung zuzuführen.
     


    Revendications

    1. Aube (30) pour un moteur à turbine à gaz comprenant :

    des parois de pression et d'aspiration (38, 40 ; 140) espacées l'une de l'autre et jointes au niveau de bords d'attaque et de fuite (34, 36) pour fournir une aube (30) qui s'étend dans une direction radiale, l'aube (30) ayant un passage de refroidissement (44) agencé entre les parois de pression et d'aspiration (38, 40 ; 140) qui s'étend vers une pointe (32) de l'aube (30), la pointe (32) comportant une poche (42) séparant les parois de pression et d'aspiration (38, 40) ; et

    des trous de refroidissement biseautés (50 ; 150) reliant de manière fluidique le passage de refroidissement (44) à la poche (42), les trous de refroidissement biseautés (50 ; 150) comportant une partie (53) encastrée dans une face de l'une de la paroi de pression (38) et de la paroi d'aspiration (40 ; 140) et exposée à la poche (42) et dans laquelle la paroi de pression a une encoche (46) au niveau du bord de fuite (36) qui est en communication fluidique avec la poche (42),

    caractérisée en ce que les trous de refroidissement biseautés (50 ; 150) comportent un premier ensemble de trous de refroidissement biseautés (50 ; 150) et un second ensemble de trous de refroidissement biseautés (56 ; 156) agencés dans la poche (42) adjacente à l'encoche (46) qui sont orientés différemment par rapport au premier ensemble de trous de refroidissement biseautés (50 ; 150) et selon un certain angle par rapport à la direction radiale.


     
    2. Aube selon la revendication 1, dans laquelle la partie (53) est encastrée dans une face de la paroi d'aspiration (40 ; 140).
     
    3. Aube selon la revendication 2, dans laquelle la paroi d'aspiration (40 ; 140) se termine dans un bord latéral d'aspiration (54 ; 154) au niveau de la pointe (32 ; 132) ; les trous de refroidissement biseautés (50 ; 150) s'étendant en direction du bord latéral d'aspiration (54 ; 154).
     
    4. Aube selon la revendication 2 ou 3, dans laquelle les trous de refroidissement biseautés (50 ; 150) forment un certain angle par rapport à la direction radiale.
     
    5. Aube selon l'une quelconque des revendications 2 à 4, comprenant une paroi d'extrémité (43 ; 143) joignant les parois de pression et d'aspiration (38 ; 40 ; 140) au niveau de la poche (42), les trous de refroidissement biseautés (50 ; 150) s'étendant à travers la paroi d'extrémité (43 ; 143).
     
    6. Aube selon la revendication 5, comprenant d'autres trous de refroidissement (48) s'étendant à travers la paroi d'extrémité (43 ; 143) et espacés des parois de pression et d'aspiration (38, 40 ; 140).
     
    7. Aube selon l'une quelconque des revendications 2 à 6, dans laquelle les trous de refroidissement biseautés (50 ; 150) comportent une section transversale semicirculaire.
     
    8. Aube selon l'une quelconque des revendications 2 à 6, dans laquelle les trous de refroidissement biseautés (150) comportent une section transversale non semicirculaire.
     
    9. Aube selon la revendication 8, dans laquelle la paroi d'aspiration (140) se termine dans un bord latéral d'aspiration (154) au niveau de la pointe (132), et les trous de refroidissement biseautés (150) comportent une partie col (58) adjacente à une partie diffuseur (60), la partie diffuseur (60) se terminant au niveau du bord latéral d'aspiration (154).
     
    10. Aube selon l'une quelconque des revendications 2 à 9, dans laquelle l'aube (30) est une pale de turbine.
     
    11. Moteur à turbine à gaz (10) comprenant :

    un compresseur (12) et la section de turbine (14) montée sur un arbre (16), et une chambre de combustion (18) agencée entre le compresseur (12) et la section de turbine (14) ; et

    une aube (30) dans l'un du compresseur et des sections de turbine (12, 14), l'aube (30) étant une aube selon l'une quelconque des revendications 2 à 10.


     
    12. Moteur à turbine à gaz selon la revendication 11, dans laquelle l'aube (30) est une pale dans la section de turbine (14) .
     
    13. Moteur à turbine à gaz selon la revendication 11 ou 12, comprenant une turbine de puissance (20) en aval de la section de turbine (14), la turbine de puissance (20) étant couplée à un générateur (22) configuré pour fournir de l'énergie à un réseau électrique (23).
     




    Drawing

















    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description