Turbine wheel for a turbomachine and turbomachine
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
Smart Images
Figure FR2026050039_30072026_PF_FP_ABST
Abstract
Description
Turbine wheel for a turbomachine including a damper having at least one groove Technical Field [OOOlJThe present invention relates to a turbine wheel for a turbomachine, as well as a turbomachine such as a turbojet or aircraft turboprop equipped with such a wheel.
[0002] The invention relates more particularly to the cooling of a sealing and damping element intended for use in the aforementioned turbine wheel. Previous technique
[0003] Typically, a high-pressure turbine wheel of a turbomachine, as shown in Figures 1 and 2, comprises a disk 1 carrying blades 3 regularly distributed circumferentially around the axis of rotation of the wheel and having feet 4 which are engaged in substantially axial recesses 2 positioned at the periphery of the disk 1. The blade feet 4 may be of the fir cross-section or dovetail type.
[0004] Each blade 3 comprises a blade 6 connected at its inner radial end to a platform 5, which is itself connected to the foot 4. The upstream and downstream ends of each platform 5 are connected respectively to an upstream radial wall 7 extending radially into the interior of the blade and to a downstream radial wall 8 extending radially into the interior of the blade. In the mounting position, the platforms 5 are arranged circumferentially end-to-end to form an internal annular flow wall for a primary airflow F originating from an airflow taken downstream of the last stage of a high-pressure compressor. Similarly, the upstream radial walls 7 and downstream radial walls 8 are arranged circumferentially opposite each other.
[0005] The wheel includes inter-blade cavities 9 distributed circumferentially around the axis of rotation of the wheel and defined radially outwards by the inner faces of two platforms 5 facing circumferentially, radially inwards by a tooth 31 of the disc 1, axially by two radial walls upstream 7 and downstream 8 whose ends are arranged circumferentially opposite, and circumferentially by the feet 4 of the blades 3.
[0006] However, during turboshaft engine operation, vibrations are induced in the turbine blades. These vibrations can lead to premature blade fatigue failure.
[0007] To dissipate the energy of these vibrations and thus reduce the amplitude of the vibrations and the associated stresses, it is known to mount vibration sealing and damping devices 13 (commonly called "candies") in the inter-blade cavities 9, as illustrated in Figure 2 and described in documents FR3027950 and EP1507960.
[0008] Each vibration-damping and sealing element 13 is held in position within the inter-blade cavity 9 by protruding lugs 32 within the cavity. As the turbine disk rotates, centrifugal force presses the elements 13 against the platforms 5, so that the lugs 32 no longer provide a retaining function. When the blades vibrate, the surfaces of the vibration-damping and sealing element 13 and the platforms 5 slide against each other to produce effective frictional forces that absorb vibrations and thus dissipate a large portion of the vibrational energy.
[0009] Furthermore, the blade platforms define the radially inner limits of the main stream and are therefore subjected to the high temperatures exiting the combustion chamber. Since the blades are sectored, there are inter-sector spaces or gaps 36 extending axially between circumferentially adjacent blade platforms, through which the hot air from the main stream can be drawn radially into the inter-blade cavities located radially beneath the platforms. It is known to use sealing and damping elements 13 that come into contact with the inner faces of the platforms and span these gaps 36 to block the radial flow of the primary air F. The sealing and damping elements 13 thus incorporate a gap-sealing function for the gaps 36.
[0010] However, such components need to be improved to better withstand the temperature constraints of the environment which can, in most cases, reach and exceed the operating temperature limit of the sealing and damping component.
[0011] We are familiar with document US5281097, which proposes drilling through the components to supply air from the inter-blade cavities into ducts machined on the internal surfaces of the platforms. The air circulates through these ducts and is then exhausted into the inter-sector spaces, thus cooling the blade platforms and the sealing and damping components. However, drilling into organs significantly reduces the lifespan of the organ and leads to the formation of cracks around the holes.
[0012] Documents US2013171003 and US2012063916 also describe another, more efficient solution for cooling blade platforms: creating internal cooling cavities within the blade platforms. The solution proposed in document US2013171003 reduces the component temperature due to heat conduction from the blade to the component, but it does not reduce the maximum temperature reached by the component in relation to the inter-sector space.
[0013] These solutions do not resolve the cooling issues for the sealing and damping components and result in a significant reduction in the material thickness of the platforms. These solutions require thickening the platform, which leads to a significant increase in the disk's mass. Description of the invention
[0014] The invention therefore aims to resolve at least in part these drawbacks by proposing a turbine wheel for a turbomachine that allows the sealing and damping components to be cooled more efficiently without modifying the design of the blades and more specifically without reducing the thickness of the platform.
[0015] The invention relates to a turbine wheel for a turbomachine, the wheel being rotatable about an axis of rotation and comprising a disk having a plurality of recesses opening onto the outer periphery of the disk, and a plurality of circumferentially adjacent blades, each blade comprising a foot mounted in one of the recesses, a platform from which a blade extends, an upstream radial wall, and a downstream radial wall extending radially toward the disk from the platform. The turbine wheel comprises a plurality of inter-blade cavities. Each inter-blade cavity is arranged between a pair of two circumferentially adjacent blades.Each inter-blade cavity is bounded radially by one radially external face of the disc and by two radially internal faces of the respective platforms of the two circumferentially adjacent blades, and by two circumferential end faces of the respective roots of the pair of two circumferentially adjacent blades, and axially by two upstream radial walls and two downstream radial walls of the two circumferentially adjacent blades. Each inter-blade cavity houses a sealing and damping element. A gap is formed between the platforms of the two circumferentially adjacent blades, the gap being located radially opposite the sealing and damping element.
[0016] The sealing and damping element comprises at least one groove formed in a recess and positioned at the upstream end portion of the sealing and damping element. This at least one groove extends along an external face of the sealing and damping element. The upstream end portion is adjacent to the upstream radial walls of the two circumferentially adjacent blades. This at least one groove is configured to fluidly connect the inter-blade cavity to the gap when the sealing and damping element is supported against the platforms of the two circumferentially adjacent blades.
[0017] The sealing and damping element comprises an upstream edge positioned on the upstream end portion, facing the upstream radial walls of the two circumferentially adjacent blades. This upstream edge is curved radially inward toward the sealing and damping element. The groove is an axial groove extending radially along the upstream edge of the sealing and damping element and axially along its outer face. The axial groove is positioned radially opposite and along the gap, its shape being curved in the axial direction.
[0018] The invention thus provides a turbine wheel for a turbomachine that cools the sealing and damping components more efficiently than known solutions, without modifying the blade design and, more specifically, without reducing the minimum platform thickness. This makes it possible to use platforms with a thin profile (less than 0.12 mm) and preferably at least 0.8 mm, corresponding to an acceptable minimum thickness.
[0019] Indeed, the groove draws air from the radially internal space beneath the component and directs it into the radially external space above, creating a film of cooled air within the gap. This improves the thermal resistance of the sealing and damping element without altering the turbine blade design or increasing its weight, unlike existing solutions.
[0020] The axial groove cools the gap more effectively.
[0021] In some embodiments, the axial groove extends radially along the upstream edge to an upstream end of the sealing and damping element.
[0022] In some embodiments, the axial groove comprises an upstream end portion, a downstream end portion and an intermediate portion connecting the downstream and upstream end portions, the intermediate portion having a circular arc-shaped cross-section and a constant depth PI.
[0023] In some embodiments, the intermediate portion has a width 11 that is greater than a width 12 of the gap. The width 11 is measured transversely with respect to the longitudinal extension direction of the sealing and damping element. The width 12 of the gap is measured between the platforms of the two circumferentially adjacent blades.
[0024] This allows for a significant airflow into the gap.
[0025] In some embodiments, the downstream end part has an elongated shape, and a depth and width that gradually decrease in a direction opposite to the upstream edge.
[0026] In some embodiments, the downstream end portion includes a pointed end.
[0027] This shape allows a portion of the airflow to be guided more efficiently towards the downstream part of the gap.
[0028] In some embodiments, the wheel includes at least one groove positioned at the upstream part of the inter-blade cavity and formed on an inner face of one of the two circumferentially adjacent blades partially delimiting the inter-blade cavity, the groove and the groove being arranged at least partially opposite each other and in particular arranged at least partially radially opposite each other.
[0029] This solution allows the sealing and damping element to be cooled even more effectively.
[0030] The sealing and damping element may include an axial groove or an axial groove combined with at least one circumferential groove. A groove may be associated with both an axial groove and a circumferential groove.
[0031] When a groove is at least partially opposite the axial groove, it is formed on one of the upstream radial walls.
[0032] Preferably, a groove is formed on each of the two circumferentially adjacent upstream radial walls. The two grooves are opposite each other.
[0033] The invention also relates to a turbomachine comprising a turbine wheel as defined above.
[0034] The terms "upstream" and "downstream" are defined in relation to the direction of air flow in the turbomachine.
[0035] The aforementioned features and advantages, as well as others, will become apparent upon reading the detailed description that follows, along with examples of wheel designs. This detailed description refers to the attached drawings. Brief description of the drawings
[0036] The attached drawings are schematic and are primarily intended to illustrate the principles of the presentation.
[0037] In these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference symbols.
[0038] [Fig. 1] Figure 1 schematically represents two adjacent turbine wheel blades, according to the known technique;
[0039] [Fig. 2] Figure 2 schematically represents, according to an axial section, a portion of a sealing and damping element housed in an inter-blade cavity, according to the known technique;
[0040] [Fig. 3] Figure 3 schematically represents a sealing and damping element comprising an axial groove, according to one embodiment of the invention;
[0041] [Fig. 4] Figure 4 schematically represents an axial cross-sectional view of the sealing and damping element of Figure 3 positioned in an inter-blade cavity;
[0042] [Fig. 5] Figure 5 schematically represents a perspective view of the sealing and damping element of Figure 3 positioned in the inter-blade cavity;
[0043] [Fig. 6] Figure 6 schematically represents a variant of the sealing and damping device;
[0044] [Fig. 7] Figure 7 schematically represents an axial cross-sectional view of the sealing and damping element of Figure 6 positioned in an inter-blade cavity;
[0045] [Fig. 8] Figure 8 schematically represents a sealing and damping element comprising an axial groove, according to another embodiment of the invention;
[0046] [Fig. 9] Figure 9 schematically represents a sealing and damping element comprising an axial groove, according to another embodiment of the invention;
[0047] [Fig. 10] Figure 10 schematically represents a sealing and damping element comprising an axial groove, according to another embodiment of the invention;
[0048] [Fig. 11] Figure 11 schematically represents a sealing and damping element comprising an axial groove, according to another embodiment of the invention;
[0049] [Fig. 12] Figure 12 schematically represents a sealing and damping element comprising an axial groove, according to another embodiment of the invention;
[0050] [Fig. 13] Figure 13 schematically represents a sealing and damping element comprising two axial grooves, according to another embodiment of the invention;
[0051] [Fig. 14] Figure 14 schematically represents a sealing and damping element comprising two axial grooves, according to another embodiment of the invention;
[0052] [Fig. 15] Figure 15 schematically represents a sealing and damping element comprising four axial grooves, according to another embodiment of the invention;
[0053] [Fig. 16] Figure 16 schematically represents a sealing and damping element of Figure 15 mounted in an inter-blade cavity, according to another embodiment of the invention;
[0054] [Fig. 17] Figure 17 schematically represents a groove formed in the wall of a blade, according to another embodiment of the invention;
[0055] [Fig. 18] Figure 18 schematically represents a sealing and damping element comprising a circumferential groove in fluid communication with the groove of Figure 17, according to another embodiment of the invention;
[0056] [Fig. 19] Figure 19 schematically represents a circumferential section of the circumferential groove and the throat of Figure 18. Description of the implementation methods
[0057] To make the explanation more concrete, an example of a turbine wheel is described in detail below, with reference to the attached drawings. It should be noted that the invention is not limited to this example.
[0058] Figure 1 partially represents a high-pressure turbine wheel of a prior art turbomachine comprising a disk 1 carrying blades 3 regularly distributed circumferentially around an axis of rotation of the wheel and having feet 4 engaged in substantially axial recesses 2 positioned at the periphery of the disk 1. The axis of rotation extends along an axial direction X. The blade feet 4 may be of the fir-tree or dovetail cross-section type. The wheel is free to rotate about the axis of rotation.
[0059] Each blade 3 comprises a blade 6 connected at its inner radial end to a platform 5, which is itself connected to the foot 4. The blade 6 extends in a radial direction Y. The upstream and downstream ends of each platform 5 are connected respectively to an upstream radial wall 7 extending radially into the blade 3 and to a downstream radial wall 8 extending radially into the blade 3. In the mounting position, the platforms 5 are arranged circumferentially end-to-end, in a tangential direction Z, to form an internal annular flow wall for a primary airflow F originating from an airflow taken downstream of the last stage of a high-pressure compressor. Similarly, the upstream radial walls 7 and downstream radial walls 8 are arranged circumferentially opposite each other.
[0060] The wheel includes inter-blade cavities 9 distributed circumferentially around the axis of rotation of the wheel and defined radially outwards by radially internal faces 11 of the respective platforms 5 of the two adjacent blades 3 circumferentially opposite each other, radially inwards by a radially external face 10 of a tooth 31 of the disc 1, axially by two radial walls upstream 7 and downstream 8 whose ends are arranged circumferentially opposite each other, and circumferentially by two circumferential end faces 12 of the respective feet 4 of the two blades 3.
[0061] However, during the operation of the turboshaft engine, vibrations are induced in the turbine blades 3. These vibrations can lead to premature fatigue failure of the blades 6.
[0062] To dissipate the energy of these vibrations and thus reduce the amplitude of the vibrations and the associated stresses, the wheel includes vibration sealing and damping elements 13 (commonly called "candies") housed in the inter-blade cavities 9. The sealing and damping elements 13 are made of metal.
[0063] Each sealing and vibration-damping element 13 is held in position in the inter-blade cavity 9 by protruding lugs 32 in the inter-blade cavity 9.
[0064] The lugs 32 can be positioned on the upstream radial walls 7 and downstream walls 8 of each blade 3 as illustrated in Figure 2 according to the prior art or be positioned on the circumferential end faces 12 of the feet 4 of each blade 3, as illustrated according to one of the embodiments of the invention in Figure 17. These lugs 32 thus form supports for the sealing and damping elements 13 when the turbomachine is stopped and when the sealing and damping elements 13 are mounted in the inter-blade cavities 9.
[0065] When the turbine disc 1 rotates, the centrifugal force presses the sealing and damping elements 13 against the platforms 5 so that the lugs 32 no longer provide a retaining function.
[0066] Since the blades 3 are sectorized, there are inter-sector spaces called "interstices" 36 which extend axially between the platforms 5 of adjacent blades 3 through which hot air from the main vein can be ingested radially into the inter-blade cavities 9.
[0067] As illustrated in the embodiment of Figure 8, each sealing and damping element 13 comprises an upstream edge 33 and a downstream edge 34 flared radially inwards, as well as two circumferential end edges 28, 30 flared and curved which follow the sides of the blades 3 radially under the platforms 5.
[0068] The upstream edges 33 and downstream edges 34 are designed to be in the immediate vicinity of the upstream radial walls 7 and downstream radial walls 8 of the two adjacent blades, in order to limit leakage through the gap 36 separating the adjacent platforms 5. Each sealing and damping element 13 comprises an external face 22 including a radially external face 41 connected to the upstream edges 33 and downstream edges 34 and to the circumferential end edges 28, 30 which extend radially inwards.
[0069] The radially external face 41 presses against the radially internal faces 11 of two circumferentially adjacent platforms 5 under the action of centrifugal force when the wheel is rotating, which ensures the sealing of the gap 36 separating the circumferentially adjacent platforms 5.
[0070] The sealing and damping element 13 comprises an upstream end portion 23 which is adjacent to the upstream radial walls 7 of the two circumferentially adjacent blades 3. The upstream edge 33 is positioned on the upstream end portion 23, facing the upstream radial walls 7.
[0071] The sealing and damping element 13 includes at least one groove 21, 21' positioned at the upstream end part 23 of the sealing and damping element 13 and extending over the external face 22 of the sealing and damping element 13. The groove 21, 21' is configured to fluidly connect the inter-blade cavity 9 to the gap 36 when the sealing and damping element 13 is in contact with the platforms 5 of the two circumferentially adjacent blades.
[0072] The groove 21, 21' extends at least from an edge 28, 30, 33 of the sealing and damping member 13 to the radially external face 41 of the external face 22. The groove 21, 21' has at least one portion positioned opposite the gap 36. The groove 21, 21' forms a recess in the sealing and damping member 13.
[0073] According to an embodiment illustrated in figures 3 to 7, the groove 21, 21' is an axial groove 21' which extends at least radially over an upstream edge 33 of the sealing and damping element 13, the axial groove 21' being positioned opposite the gap 36 and running along the gap 36.
[0074] Preferably, the axial groove 21' extends radially (along the radial direction Y) over an upstream edge 33 of the sealing and damping member 13, from an upstream end 50 of the sealing and damping member 13, and axially (along the axial direction X) over the radially external face 41 of the sealing and damping member 13, towards the downstream edge 34 of the sealing and damping member 13.
[0075] The axial groove 21' has a curved shape along the axial direction X.
[0076] The axial groove 21' comprises an upstream end portion 57, a downstream end portion 52 and an intermediate portion 51 connecting the downstream and upstream end portions 52, 57. The intermediate portion 51 has a circular arc-shaped cross-section with a depth PI and a width 11. The depth PI and / or the width 11 and / or the radius of the intermediate portion 51 are constant.
[0077] The upstream end portion 57 and the intermediate portion 51 have the same radius, depth PI, and width. The downstream end portion 52 has a curved bottom 59 and two opposing curved edges 60. The downstream end portion 52 has a rounded (or spherical) shape.
[0078] As illustrated in Figure 5, the axial groove 21' is adjacent to two upstream radial walls 7 of two circumferentially adjacent blades 3. The axial groove 21' is located at the junction (the gap 36) of two circumferentially adjacent blades 3.
[0079] Preferably, the axial groove 21' is aligned with the gap 36 and is centered with respect to the gap 36.
[0080] For example, the wall of the sealing and damping element 13 has a thickness greater than or equal to 0.3 mm, a radius greater than 1 mm, a depth PI greater than 0.5 mm and a width 11 greater than 3 mm.
[0081] Advantageously, the width 11 is greater than a width 12 of the gap 36, as illustrated in Figure 5. Preferably, the width 11 is greater than at least twice the width 12 of the gap 36, and even more preferably, greater than at least three times the width 12 of the gap 36.
[0082] Figure 4 represents a single upstream radial wall 7 and an axial section of the sealing and damping element 13 passing through the middle of the axial groove 21'. A half axial groove 21' is thus represented.
[0083] The axial half-groove 21' runs along the inner face 58 of one of the two circumferentially adjacent blades 3.
[0084] The complete axial groove 21' runs along each inner face 58 of the two circumferentially adjacent blades 3. The upstream end portion 57 of the axial groove 21' is positioned opposite the two upstream radial walls 7.
[0085] The intermediate part 51 of the axial groove 21' which is located at the place of the upstream edge 33 of the sealing and damping element 13, runs radially along the two upstream radial walls 7 and then axially along the two platforms 5 of the two circumferentially adjacent blades 3.
[0086] The inter-blade cavity 9 comprises a radially internal space 16 and a radially external space 17, which are separated by the sealing and damping element 13. The radially internal space 16 is bounded radially by the radially external face 10 of the disc 1 and a radially internal face of the sealing and damping element 13, opposite the radially external face 41 of the sealing and damping element 13. The radially external space 17 is bounded radially by the radially external face 41 of the sealing and damping element 13 and two radially internal faces 11 of two adjacent platforms 5. The radially external space 17 communicates with the gap 36.
[0087] An air inlet 61 is formed between the upstream end portion 57 of the axial groove 21' and the two upstream radial walls 7. The air inlet 61 allows air from the radially internal space 16 of the inter-blade cavity 9, located radially below the sealing and damping element 13, to enter a channel 63 formed between the axial groove 21' and the two upstream radial walls 7, and then into the radially external space 17, located radially above the sealing and damping element 13, when the sealing and damping element 13 is pressed against the platform 5 by the centrifugal force caused by the rotation of the impeller. The air inlet 61 and the channel 63 are open and communicate with the gap 36.
[0088] As illustrated in Figure 3, the axial groove 21' extends over a length L1 which corresponds to at least l / 6 èmeof the axial length of the sealing and damping element 13. The length must be sufficient to create a cold air film on the external face 22 of the sealing and damping element 13 and in the gap 36.
[0089] According to another embodiment shown in Figures 6 and 7, the downstream end portion 52 has an elongated shape. The downstream end portion 52 extends axially in the direction of the downstream edge 34 of the sealing and damping element 13 over a non-zero length L2, which preferably corresponds to at least l / 6 ème of the length L1 of the axial groove 21'. The downstream end part 52 has a depth and width that gradually (or regularly) decrease to zero values respectively, following the direction of the downstream edge 34. The downstream end part 52 includes a pointed end 62.
[0090] According to another embodiment shown in Figures 8 to 19, the groove 21, 21' is a circumferential groove 21 which extends circumferentially over the external face 22 of the sealing and damping member 13 such that a part of the circumferential groove 21 is positioned near and preferably opposite a part of the gap 36, as illustrated in Figures 16, 18 and 19. A part of the circumferential groove 21 covers or crosses a part of the gap 36.
[0091] The circumferential groove 21 extends at least from a circumferential end edge 28, 30 of the sealing and damping member 13 to an intermediate zone 25 of the sealing and damping member 13. The intermediate zone 25 is positioned opposite the gap 36.
[0092] The circumferential groove 21 is positioned at the upstream end part 23 of the sealing and damping member 13. The circumferential groove 21 runs at least partially along the upstream edge 33 of the sealing and damping member 13. More precisely, the circumferential groove 21 runs along a curved upstream portion 42 of the sealing and damping member 13 connecting the upstream edge 33 to the radially external face 41 of the sealing and damping member 13.
[0093] The circumferential groove 21 is formed by stamping.
[0094] The first circumferential end edge 28 of the sealing and damping member 13 is radially delimited inwards by a first circumferential end 24. The second circumferential end edge 30 of the sealing and damping member 13 is radially delimited inwards by a second circumferential end 29.
[0095] According to the example in Figure 8, the circumferential groove 21 partially follows the upstream edge 33 of the sealing and damping element 13 in the radial direction Y. The circumferential groove 21 extends in the circumferential direction X from an intermediate zone 25 of the sealing and damping element 13 to the first circumferential end edge 28 of the sealing and damping element 13. The intermediate zone 25 is located substantially on a vertex of the sealing and damping element 13 and is positioned radially below the gap 36. The circumferential groove 21 includes a first end portion 26 which follows the first curved longitudinal portion 40 of the sealing and damping element 13 and extends towards the first circumferential end edge 28.The first end part 26 is distant from the first circumferential end 24 of the sealing and damping element 13.
[0096] The circumferential groove 21 extends along the outer face 22 from the first end portion 26, which is curved, to a second end portion 27, which is also curved. The portion of the groove 43 positioned between the first and second end portions 26, I, is substantially straight.
[0097] The circumferential groove 21 extends over a distance between one quarter and one half of the circumferential width of the sealing and damping element 13.
[0098] In this example, the circumferential groove 21 extends over a distance corresponding to slightly less than half the circumferential width of the sealing and damping element 13.
[0099] According to the example in Figure 9, the circumferential groove 21 extends from the intermediate zone 25 of the sealing and damping member 13 to the first circumferential end 24 of the sealing and damping member 13. The circumferential groove 21 then extends substantially over half the circumferential width of the sealing and damping member 13.
[0100] The circumferential groove 21 extends to the vicinity of the gap 36 and preferably beyond the gap 36 towards the second circumferential end edge 30 of the sealing and damping member 13. [The circumferential groove 21 allows the radially internal space 16 and the radially external space 17 to be connected fluidly when the sealing and damping member 13 is in contact with the platform 5 by the centrifugal force caused by the rotation of the wheel.
[0102] Thus, a portion of the primary airflow F from the airflow taken downstream of the last stage of the high-pressure compressor enters the radially internal space 16 and enters the circumferential groove 21 through the first end portion 26 of the circumferential groove 21. This airflow circulates radially and then circumferentially in the circumferential groove 21 before exiting through the second end portion I of the circumferential groove 21. The airflow then circulates in the radially external space 17, along the external face 22 of the sealing and damping element 13, forming an air film between the external face 22 of the sealing and damping element 13 and the two radially internal faces 11 of two circumferentially adjacent platforms 5, thus cooling the sealing and damping element 13. The air film is then discharged through the gap 36.A channel is thus formed between the circumferential groove 21 and the inner face 58 of one of the two circumferentially adjacent blades 3.
[0103] According to another example illustrated in Figure 10, the circumferential groove 21 extends circumferentially from a first circumferential end edge 28 to a second circumferential end edge 30 of the sealing and damping member 13.
[0104] According to another example illustrated in figures 11 and 12, the circumferential groove 21 extends circumferentially from the first circumferential end 24 of the sealing and damping member 13 to the second circumferential end 29 of the sealing and damping member 13.
[0105] The first end portion 26 of the circumferential groove 21 is oriented radially inwards and is positioned at the first circumferential end 24 of the sealing and damping member 13. The second end portion ZI of the circumferential groove 21 is oriented radially inwards and is positioned at the second circumferential end 29 of the sealing and damping member 13.
[0106] The circumferential groove 21 then extends over the entire circumferential width of the sealing and damping element 13, promoting good distribution of the airflow.
[0107] The circumferential groove 21 runs along the first curved longitudinal portion 40 of the sealing and damping member 13 and extends along the first longitudinal edge 28 to the first circumferential end 24. The circumferential groove 21 runs along a second curved longitudinal portion 44 of the sealing and damping member 13 and extends along the second circumferential end edge 30 to the second circumferential end 29 of the sealing and damping member 13. The circumferential groove 21 extends over the external face 22.
[0108] Alternatively, the circumferential groove 21 can extend from the first circumferential end edge 28 of the sealing and damping member 13 to the second circumferential end 29 of the sealing and damping member 13 or the second circumferential end edge 30.
[0109] The circumferential groove 21 has a circular arc-shaped cross-section with a radius of curvature between 0.5 mm and 1.5 mm, preferably equal to 1 mm. The circumferential groove 21 has a depth greater than or equal to 0.2 mm.
[0110] According to another variant illustrated in Figures 13 and 14, the sealing and damping member 13 comprises at least two circumferential grooves 21 positioned on the upstream end part 23 of the sealing and damping member 13. Each circumferential groove 21 extends circumferentially and at least partially over an external face 22 of the sealing and damping member 13. [011 l]The circumferential grooves 21 run at least partially along the upstream edge 33 of the sealing and damping member 13. More precisely, the circumferential grooves 21 run along a curved upstream portion 42 of the sealing and damping member 13 connecting the upstream edge 33 to the radially external face 41 of the sealing and damping member 13.
[0112] According to an example illustrated in Figure 13, the sealing and damping element 13 comprises two substantially parallel circumferential grooves 21. Each circumferential groove 21 extends from the first circumferential end edge 28 to the second circumferential end edge 30. The circumferential grooves 21 are separated by a distance of less than 5 mm.
[0113] The circumferential grooves 21 extend circumferentially over almost the entire width of the sealing and damping element 13, over a distance greater than three-quarters of the circumferential width of the sealing and damping element 13. The second end part 27 of each groove 21 is positioned on the second circumferential end edge 30 of the sealing and damping element 13 and is distant from the second circumferential end 29 of the sealing and damping element 13.
[0114] The first end portion 26 of each circumferential groove 21 is positioned on the first curved longitudinal portion 40 of the sealing and damping member 13 and extends towards the first circumferential end edge 28. The second end portion I of each circumferential groove 21 is positioned on a second curved longitudinal portion 44 of the sealing and damping member 13 and extends slightly towards the second circumferential end edge 30.
[0115] Each circumferential groove 21 extends over the external face 22 from the first end part 26 of the circumferential groove 21 which is curved to the second end part ZI of the circumferential groove 21 which is also curved.
[0116] According to an example illustrated in Figure 14, the circumferential grooves 21 extend circumferentially over the entire width of the sealing and damping member 13, from the first circumferential end 24 of the sealing and damping member 13 to the second circumferential end 29 of the sealing and damping member 13.
[0117] According to another example illustrated in Figures 15 and 16, the sealing and damping member 13 comprises four substantially parallel circumferential grooves 21a, 21b, 21c, 21d, of which a first circumferential groove 21a and a second circumferential groove 21b extend from a first circumferential end edge 28 of the sealing and damping member 13 to an intermediate zone 25 of the sealing and damping member 13 positioned between the first circumferential end edge 28 and the second circumferential end edge 30. The intermediate zone 25 is located substantially on a crest of the sealing and damping member 13 which is circumferentially curved.
[0118] The sealing and damping member 13 also includes a third circumferential groove 21c and a fourth circumferential groove 21d extending from a second circumferential end edge 30 of the sealing and damping member 13 to the intermediate area 25.
[0119] The four circumferential grooves 21a, 21b, 21c, 21d partially run along the upstream edge 33 of the sealing and damping member 13 and are positioned on the side of the upstream end part 23 of the sealing and damping member 13.
[0120] The first and second circumferential grooves 21a, 21b include a first end portion 26 positioned on the first curved longitudinal portion 40 of the sealing and damping member 13 and extending slightly towards the first circumferential end edge 28. The first end portions 26 are distant from the first circumferential end 24 of the sealing and damping member 13.
[0121] The third and fourth circumferential grooves 21c, 21d comprise a first end part 26 positioned on the second curved longitudinal portion 44 of the sealing and damping member 13 and extending slightly towards the second circumferential end edge 30. The first end parts 26 are distant from the second circumferential end 29 of the sealing and damping member 13.
[0122] The four circumferential grooves 21a, 21b, 21c, 21d extend circumferentially along the outer face 22 from the first end portion 26, which is curved, to the second end portion 27, which is also curved. The groove portions 43 positioned between the first and second end portions 26, 1 are substantially straight.
[0123] The circumferential grooves 21a, 21b, 21c, 21d are arranged in a staggered pattern. Along the intermediate zone 25, the second end sections ZI of the first and second circumferential grooves 21a, 21b alternate with the second end sections ZI of the third and fourth circumferential grooves 21c, 21d. The second end sections ZI of the first and second circumferential grooves 21a, 21b are circumferentially adjacent to the second end sections ZI of the third and fourth circumferential grooves 21c, 21d. The second end sections ZI of the first and second circumferential grooves 21a, 21b intersect with the second end sections ZI of the third and fourth circumferential grooves 21c, 21d.
[0124] The four circumferential grooves 21a, 21b, 21c, 21d are spaced from each other by the same distance.
[0125] The four circumferential grooves 21a, 21b, 21c, 21d extend circumferentially over a distance between one quarter and three quarters of the width of the sealing and damping element 13.
[0126] The first and second circumferential grooves 21a, 21b extend to the vicinity of the gap 36 and preferably beyond the gap 36, towards the second circumferential end edge 30 of the sealing and damping member 13.
[0127] The third and fourth circumferential grooves 21c, 21d extend to the vicinity of the gap 36 and preferably beyond the gap 36, towards the first circumferential end edge 28 of the sealing and damping member 13.
[0128] As illustrated in Figure 16, the four circumferential grooves 21a, 21b, 21c, 21d cross the gap 36 to supply it with air.
[0129] According to another variant (not shown), the first and second circumferential grooves 21a, 21b can extend from the intermediate zone 25 of the sealing and damping element 13 to the first circumferential end 24 of the sealing and damping element 13. The third and fourth circumferential grooves 21c, 21d can extend from the intermediate zone 25 of the sealing and damping element 13 to the second circumferential end 29 of the sealing and damping element 13. The four circumferential grooves 21a, 21b, 21c, 21d then extend over at least one-quarter of the circumferential width of the sealing and damping element 13.
[0130] Each groove 21, 21a, 21b, 21c, 21d has a circular arc-shaped cross-section with a radius of curvature between 0.5 mm and 1.5 mm, preferably equal to 1 mm. Each groove 21, 21a, 21b, 21c, 21d has a depth greater than or equal to 0.2 mm.
[0131] Alternatively, each groove 21 can extend from the first circumferential end edge 28 of the sealing and damping member 13 to the second circumferential end 29 of the sealing and damping member 13.
[0132] According to another embodiment illustrated in Figures 17 to 19, at least one of the blades 3 includes a groove 14 formed in the foot 4 of the blade 3, along the circumferential end face 12 of the foot 4 and in the platform 5 of the blade 3, along the radially internal face 11, forming a grooved blade. The groove 14 is positioned at an upstream part 53 of the inter-blade cavity 9 and is formed on an inner face 58 of one of the two circumferentially adjacent blades 3 which partially delimit the inter-blade cavity 9. The groove 14 extends from the circumferential end face 12 of the foot 4 to the radially inner face 11 of the platform 5. The groove 14 is positioned inside the inter-blade cavity 9 and runs at least partially along the upstream radial wall 7 of the blade 3.
[0133] The groove 14 and the circumferential groove 21 are arranged at least partially opposite each other.
[0134] As illustrated in Figure 17, the groove 14 is cut into the material. The groove 14 has a generally elongated shape, forming a groove or channel. The groove 14 also has a curved shape.
[0135] The inter-blade cavity 9 is partly delimited by a curved wall 20 connecting the circumferential end face 12 of the foot 4 to the radially internal face 11 of the platform 5. A portion of the groove 14 is formed in the curved wall 20 by conforming to its shape.
[0136] The groove 14 extends along the curved wall 20 from a first end 37 positioned on a radially external portion 15 of the circumferential end face 12 of the foot 4 to a second end 38 positioned on a circumferential end portion 39 of the radially internal face 11 of the platform 5. The radially external portion 15 is an area of the circumferential end face 12 that is adjacent to or near the platform 5. The circumferential end portion 39 of the radially internal face 11 corresponds to a portion near or adjacent to the circumferential end face 12 of the foot 4.
[0137] The groove 14 comprises a first part 18 extending radially over the radially external portion 15 of the circumferential end face 12 of the foot 4 and a second part 19 extending substantially circumferentially over the circumferential end portion 39 of the radially internal face 11 of the platform 5 from the first part 18.
[0138] The groove 14 is adjacent to the upstream radial wall 7 of the blade 3. The groove 14 is at a distance between 0.1 mm and 1 mm from the upstream radial wall 7.
[0139] The groove 14 can have a regular or irregular cross-section. The groove 14 has a C-shaped cross-section, that is, an arc of a circle with a radius of curvature greater than 1 mm.
[0140] The groove 14 has a length between 3 mm and 6 mm, and preferably equal to 4 mm.
[0141] The groove 14 has a depth less than a quarter of the thickness of the platform 5, and preferably strictly greater than 0.2 mm.
[0142] The thickness of platform 5 is strictly greater than 0.8 mm even at the location of the groove 14.
[0143] According to one variant, each inter-blade cavity 9 comprises a single groove 14 formed on one of the two adjacent blades 3.
[0144] Alternatively, each blade 3 is a grooved blade, each inter-blade cavity 9 comprising two grooves 14, each formed on one of the two circumferentially adjacent blades 3 and each cooperating with a circumferential groove 21. The two grooves 14 are separated circumferentially by the sealing and damping member 13.
[0145] Each inter-blade cavity 9 then comprises two grooves 14, a first groove cooperating with the first end part 26 of the circumferential groove 21 and a second groove cooperating with the second end part I of the second portion of the circumferential groove 21.
[0146] The grooves 14 can be positioned at the same distance from the upstream radial wall 7 or at different distances.
[0147] The groove 14 and the circumferential groove 21 allow the radially internal space 16 and the radially external space 17 to be connected fluidly when the sealing and damping element 13 is in contact with the platform 5 by the centrifugal force caused by the rotation of the wheel.
[0148] When the sealing and damping element 13 is in contact with the platform 5, a portion of the first circumferential end edge 28 and a portion of the first circumferential end 24 of the sealing and damping element 13 are opposite the groove 14. The portion of the first circumferential end 24 is positioned between the first and second ends 37, 38 of the groove 14 and more precisely between the first end 37 of the groove 14 and the curved wall 20.
[0149] The circumferential groove 21 and the groove 14 partially overlap, as illustrated in figures 18 and 19.
[0150] The first end portion 26 of the groove 21 is positioned opposite the second portion 19 of the groove 14. In other words, the first end portion 26 of the groove 21 and the second portion 19 of the groove 14 overlap or superimpose so as to create a fluidic communication between the groove 14 and the groove 21.
[0151] In this example, the inter-blade cavity 9 comprises two grooves 14 separated circumferentially by the sealing and damping element 13. For simplicity, only one groove 14 is shown in the figures. Each of the two circumferentially adjacent blades 3 comprises one groove 14. In other words, each blade 3 comprises two grooves 14, each positioned on either side of the blade 3.
[0152] When the sealing and damping element 13 is pressed against the platform 5 by centrifugal force during the rotation of the motor, the circumferential groove 21 and the two grooves 14 overlap at least partially.
[0153] The following is described for the groove 14 of one of the two blades 3. This description also applies to the groove 14 of the other circumferentially adjacent blade 3.
[0154] When the sealing and damping element 13 is in contact with the platform 5, the first end part 26 of the circumferential groove 21 is positioned opposite the first part 18 of the groove 14. In other words, the first end part 26 of the circumferential groove 21 and the first part 18 of the groove 14 overlap or superimpose so as to create a fluidic communication between the groove 14 and the circumferential groove 21.
[0155] The groove 14 and the circumferential groove 21 overlap over a distance greater than one-eighth of the circumferential width of the sealing and damping element 13. The distance between the second end 38 of the groove 14 and the first end part 26 of the circumferential groove 21 is greater than or equal to 1.5 mm.
[0156] Thus, a portion of the primary airflow F originating from the airflow taken downstream of the last stage of the high-pressure compressor enters the radially internal space 16 and enters the grooves 14 through the first end 37 of the grooves 14. This airflow circulates radially in the first part 18 of the grooves 14 and then circumferentially in the second parts 19 of the grooves 14 before exiting through the second end 38 of the grooves 14 to enter the circumferential groove 21. The airflow then circulates in the circumferential groove 21 and in the radially external space 17, along the external face 22 of the sealing and damping element 13, forming an air film between the external face 22 of the sealing and damping element 13 and the two radially internal faces 11 of two adjacent platforms 5, thus cooling the sealing and damping element. 13. The air film is then evacuated through gap 36.
[0157] The grooves 14 and the circumferential groove 21 form an air cooling circuit connecting the radially internal space 16 to the radially external space 17 of the inter-blade cavity 9.
[0158] Regardless of the previous embodiments, the groove 14 and the circumferential groove 21 overlap by a distance greater than or equal to 1.5 mm.
[0159] Preferably, the groove 14 also has a circular arc-shaped section.
[0160] The radius of the groove 14 is greater than the radius of the circumferential groove 21. Similarly, the depth of the groove 14 is greater than the depth of the circumferential groove 21. The width of the groove 14 is greater than the width of the circumferential groove 21. The width of the groove 14 is less than twice the width of the circumferential groove 21. The gap 36 has a circumferential width of approximately 0.5 mm, for example.
[0161] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.
Claims
Demands
1. A turbine wheel for a turbomachine, the wheel being rotatable about an axis of rotation and comprising a disk (1) having a plurality of recesses (2) opening onto the outer periphery of the disk (1), and a plurality of circumferentially adjacent blades (3), each blade (3) comprising a foot (4) mounted in one of the recesses (2), a platform (5) from which a blade (6) extends, an upstream radial wall (7) and a downstream radial wall (8) extending radially towards the disk (1) from the platform (5), said turbine wheel comprising a plurality of inter-blade cavities (9), each inter-blade cavity (9) being arranged between a pair of two circumferentially adjacent blades (3), each inter-blade cavity (9) being radially bounded by a radially external face (10) of the disk (1) and by two radially internal (11) of the respective platforms (5) of the two circumferentially adjacent blades (3),and by two circumferential end faces (12) of the respective feet (4) of the pair of two circumferentially adjacent blades (3), and axially by two respective upstream radial walls (7) and two downstream radial walls (8) of the two circumferentially adjacent blades (3), each inter-blade cavity (9) housing a sealing and damping element (13), a gap (36) being formed between the platforms (5) of the two circumferentially adjacent blades (3), the gap (36) being located radially opposite the sealing and damping element (13), in which the sealing and damping element (13) comprises at least one groove (21, 21 7formed in a hollow and positioned at the location of an upstream end portion (23) of the sealing and damping element (13) and extending over an external face (22) of the sealing and damping element (13), the upstream end portion (23) being adjacent to the upstream radial walls (7) of the two circumferentially adjacent blades (3), said at least one groove (21, 21') being configured to fluidly connect the inter-blade cavity (9) to the gap (36) when the sealing and damping element (13) is supported against the platforms (5) of the two circumferentially adjacent blades, the sealing and damping element (13) comprising an upstream edge (33) positioned on the upstream end portion (23), facing the upstream radial walls (7) of the two circumferentially adjacent blades adjacent, the upstream edge (33) being curved radially towards the interior of the sealing and damping element (13), characterized in that: - the groove (21, 217 ) is an axial groove (21 7 ) which extends radially along the upstream edge (33) of the sealing and damping element (13), and axially along the external face (22) of the sealing and damping element (13), the axial groove (21 7 ) being positioned radially opposite the gap (36) and running along the gap (36), the axial groove (21') having a curved shape along the axial direction X.
2. Wheel according to claim 1, wherein the axial groove (21 7 ) extends radially along the upstream edge (33) to an upstream end (50) of the sealing and damping element (13).
3. Wheel according to claim 1 or 2, wherein the axial groove (219) comprises an upstream end portion (57), a downstream end portion (52) and an intermediate portion (51) connecting the downstream and upstream end portions (52, 57), the intermediate portion (51) having a circular arc-shaped cross-section and a constant depth PI.
4. Wheel according to claim 3, wherein the intermediate part (51) has a width 11 which is greater than a width 12 of the gap (36).
5. Wheel according to any one of claims 3 or 4, wherein the downstream end part (52) has an elongated shape, and a depth and width that gradually decrease in a direction opposite to the upstream edge (33).
6. A wheel according to claim 5, wherein the downstream end portion (52) comprises a pointed end (62).
7. A wheel according to any one of claims 1 to 6, comprising at least one groove (14) positioned at the location of an upstream portion (53) of the inter-blade cavity (9) and formed on an inner face (58) of one of the two circumferentially adjacent blades (3) partially delimiting the inter-blade cavity (9), the groove (14) and the groove (21, 21 7 ) being arranged at least partially opposite each other.
8. Turbomachine comprising a turbine wheel according to any one of claims 1 to 7.