Waterwheel for a turbine
The turbine blade design with enhanced blade span and interlocking transverse walls addresses blade disengagement issues, ensuring efficient operation and reducing maintenance needs.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2021-03-16
- Publication Date
- 2026-06-19
AI Technical Summary
The issue of blade disengagement due to misalignment and circumferential play in turbomachine blades leads to efficiency loss, damage, and potential turbomachine stoppage, necessitating frequent dismantling and repositioning.
A turbine blade design with increased blade span and transverse walls having circumferential edges that interlock with adjacent blades, reducing tilting and dislodgement by enhancing engagement and maintaining aerodynamic continuity.
The design effectively reduces blade disengagement, maintains aerodynamic flow, and prevents turbomachine inefficiencies and damage, while minimizing the need for frequent maintenance.
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Abstract
Description
Title of the invention: Paddle wheel for a turbine Technical field of the invention
[0001] This document relates to a blade wheel for a turbine, in particular the fitting of the blades into the blade wheel. Prior art
[0002] A turbomachine is typically intended to equip an aircraft such as an airplane. Examples of turbomachines include turbojet engines and turboprop engines.
[0003] Fig. 1 illustrates a prior art turbofan engine 1. This comprises, from upstream to downstream in the direction of gas flow within the turbomachine, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, a low-pressure turbine 7 and an exhaust nozzle 8.
[0004] The air from the blower 2 is separated into two streams, namely a primary stream and a secondary stream. The primary stream passes through a primary flow channel 9 in which the low and high pressure compressors 3, 4, the combustion chamber 5 and the high and low pressure turbines 6, 7 are located. The secondary stream exits through a secondary channel 10.
[0005] The low-pressure turbine 7 drives the low-pressure compressor 3 and the blower 2, notably via a low-pressure shaft, so as to form a low-pressure unit. The high-pressure turbine 6 drives the high-pressure compressor 4 via a high-pressure shaft, so as to form a high-pressure unit.
[0006] The low-pressure turbine 7 comprises a rotor and a stator. The rotor comprises a series of bladed wheels, axially interposed between stages of rotor distributors.
[0007] The terms longitudinal, radial and circumferential are defined with respect to the axis of the turbomachine.
[0008] As illustrated in [Fig.2], a bladed wheel classically comprises a disc 11 on the outer periphery of which blades 12 are mounted.
[0009] In particular, each blade 12 comprises radially from the inside out, a foot 14, a stilt 16, a platform 18, a blade 20 and a heel 22.
[0010] The foot 14 is intended to be engaged in a socket 24 of complementary shape to the disc. Ribs 26 of the disc 11 circumferentially delimit the sockets 24 of the disc.
[0011] The blades 12 are regularly distributed around the periphery of the disk 11 so that the adjacent platforms 18, on the one hand, and the adjacent heels 22, on the other hand, define radially internal and radially external annular walls delimiting between them a part of the primary vein.
[0012] Each heel 22 conventionally includes at least one lug 28 intended to cooperate with a ring of abradable material so as to ensure dynamic sealing in operation.
[0013] Taking into account the mounting clearances between the feet 14 of the blades 12 and the recesses 24 of the disk 10, the blades 12 are able to move slightly relative to the disk 11. [Fig.3] illustrates a position in which the blades 12 extend radially, but the heels 22 of the blades 12 can move apart from each other in the circumferential direction.
[0014] Each heel 22a, 22b has two circumferential edges 30a, 30b. Cases of loss of contact between the circumferential edges 30a, 30b of heels 22a, 22b of adjacent blades are observed. This loss of contact and the circumferential play appearing between the heels 22a, 22b can generate an axial misalignment between the heels 22a, 22b of the operating blades, which can lead to the disengagement of at least one blade.
[0015] This blade disengagement can generate a loss of efficiency, damage to the turbine or even a stoppage of the turbomachine 1 in flight, and lead to the removal and dismantling of the turbomachine 1 in order to change one or more blades or to reposition the blades 12 in the correct position.
[0016] This document aims to remedy these drawbacks. Summary of the invention
[0017] To this end, the present description proposes a turbine blade wheel rotating around a longitudinal axis, comprising:
[0018] - a disk having a plurality of alveoli, each alveolus being formed by a first rib and a second successive rib of the disc, and
[0019] - a plurality of blades mounted circumferentially around said disk, each a paddle comprising a foot engaged in a recess of the disc, and each blade foot comprising a downstream transverse wall and an upstream transverse wall, the upstream and downstream transverse walls extending circumferentially around said blade foot,
[0020] the downstream transverse wall having a first circumferential end in contact with the first rib of the disc and the upstream transverse wall having a second circumferential end in contact with the second rib,
[0021] in which a circumferential distance between the first end and the second end is greater than an inter-rib circumferential distance.
[0022] Thus, the span of the blade in the disc is increased compared to the art Previous. The blade span is defined by the distance between the first end of the downstream transverse wall and the second end of the upstream transverse wall. Increasing the blade span limits blade tilt and therefore reduces blade dislodgement.
[0023] The circumferential inter-rib distance can be defined as the distance between a circumferential center of the first rib and a circumferential center of the second rib. The circumferential center of the first rib, or of the second rib respectively, can be located on a radially external surface of the first rib, or of the second rib respectively. The circumferential distance between the first end and the second end can be defined as the distance between the first end and the projection of the second end onto a radial plane including the first end, or vice versa.
[0024] Each of the first end and the second end can be arranged beyond a vertex of the first rib, respectively beyond a vertex of the second rib.
[0025] The apex of the first rib, respectively the apex of the second rib, can correspond to the circumferential center of the first rib, respectively the circumferential center of the second rib.
[0026] The downstream transverse wall of at least one blade may have a first circumferential edge a ferrular comprising the first end and a second circumferential edge opposite the first circumferential edge. The second circumferential edge of the downstream transverse wall may include a step configured to receive at least part, in particular all, of a first circumferential edge of a blade adjacent to said blade.
[0027] Similarly, the upstream transverse wall of at least one blade may have a first circumferential edge comprising the second end and a second circumferential edge opposite the first circumferential edge. The second circumferential edge of the upstream transverse wall may include a recess configured to receive at least a portion of a first circumferential edge of a blade adjacent to said blade.
[0028] The recesses can be circumferentially recesses made inwards in the second circumferential edges.
[0029] This arrangement allows for the engagement of adjacent blade platforms and reduces the space occupied by the blades within the disk. Furthermore, the interlocking of the platforms creates a continuous aerodynamic flow from the blade wheel into the turbine.
[0030] The recesses may have a different shape, for example a shape having dimensions, in particular a circumferential dimension, greater than the dimensions, in particular the circumferential dimension, of the first circular edges conferences.
[0031] The first circumferential edge of the downstream transverse wall may include a portion projecting in a circumferential direction, said projecting portion comprising the first end. The offset of the second circumferential edge of the downstream transverse wall may have a shape complementary to said projecting portion.
[0032] Similarly, the first circumferential edge of the upstream transverse wall may include a portion projecting in a circumferential direction, said projecting portion comprising the second extremity. The offset of the second circumferential edge of the upstream transverse wall may have a shape complementary to said projecting portion.
[0033] The projecting portions may extend over part or all of a radial height of the first circumferential edges. Each projecting portion may extend circumferentially outwards from the circumferential edge that includes it.
[0034] A circumferential dimension of at least one of the first circumferential edge of the upstream transverse wall and of the first circumferential edge of the downstream transverse wall, in particular at the first end and the second end, may be between 5% and 40% of the inter-rib circumferential distance, in particular between 10% and 25% of the inter-rib circumferential distance.
[0035] A circumferential dimension of at least one of the projecting portion of the first circumferential edge of the upstream transverse wall and of the projecting portion of the first circumferential edge of the downstream transverse wall, in particular at the level of the first end and the second end, may be between 5% and 40% of the inter-rib circumferential distance, in particular between 10% and 25% of the inter-rib circumferential distance.
[0036] The circumferential dimension of the first circumferential edge of the upstream transverse wall, respectively of the first circumferential edge of the downstream transverse wall, can be defined by a circumferential distance between the first end and the circumferential center of the rib in contact with the first end, respectively of the second end and the circumferential center of the rib in contact with the second end.
[0037] The circumferential dimension of the first circumferential edge of the upstream transverse wall may be different from the circumferential dimension of the first circumferential edge of the downstream transverse wall. Alternatively, the circumferential dimension of the first circumferential edge of the upstream transverse wall may be equal to the circumferential dimension of the first circumferential edge of the downstream transverse wall.
[0038] Each blade may include a heel arranged on the radially external periphery of said blade, the heel having two circumferential edges. One of the circumferential edges The rentiels of a first blade can be engaged in an adjacent circumferential edge of a second blade.
[0039] This arrangement allows for the formation of a continuous aerodynamic flow from the blade wheel into the turbine.
[0040] The circumferential edges of the upstream transverse wall and the downstream transverse wall can be made by electro-erosion machining.
[0041] The turbine can be a high-pressure turbine or a low-pressure turbine.
[0042] The present description further relates to a turbomachine comprising at least one blade wheel of the aforementioned type. Brief description of the figures
[0043] [Fig-1] is a perspective and axial cross-sectional view of a prior art turbomachine,
[0044] [Fig.2] is a perspective view of part of a prior art paddle wheel,
[0045] [Fig.3] is a front view of part of a prior art paddle wheel,
[0046] [Fig.4] is a front view of part of a paddle wheel according to a first example of realization,
[0047] [Fig.5] is an inclined bottom view of a blade of the paddle wheel of the [Fig.4],
[0048] [Fig.6] is a front view of part of a paddle wheel according to a second example of realization. Detailed description of the invention
[0049] Figures 4 and 5 show a portion of a turbine blade 100. The turbine comprises a plurality of blades 100 mounted in a disk 11. Each blade 100 has, radially from the inside out, a foot 14, a strut 16, a platform 18, a blade 20, and a heel. The foot 14 is engaged in a recess 24 of the disk 11. The recess 24 is bordered by two successive ribs 26 of the disk 11.
[0050] Similar to prior art blades, the flange 22 on the radially outer periphery of the blade 100 has two circumferential edges. The blades 100 are mounted in the disk 11 such that the adjacent platforms 18, on the one hand, and the adjacent flanges 22, on the other hand, define radially internal and radially external annular walls delimiting between them a portion of the turbine's aerodynamic duct. Thus, one of the circumferential edges of the flange 22 is in contact with one of the circumferential edges of the adjacent flange. The adjacent circumferential edges may have complementary shapes allowing the adjacent flanges to interlock.
[0051] The platform 18 extends from the Péchasse 16 of the blade 100 to the blade 20. This platform 18 is in contact with the ribs 26 and allows the blade to be locked. dialement in disc 11 in cooperation with foot 14. A blade span 100 on disc 11 is defined by the maximum contact length between platform 18 and ribs 26 of disc 11, measured perpendicular to the axis of foot 14.
[0052] Since the foot 14 is mounted with some play in the recess 24, the blades 100 can move and spread apart. This can cause one or more of the blades 100 to become dislodged. The dislodgement of the blade 100 is also influenced by the spacing of the blade 100 on the ribs 26 of the disc 11.
[0053] To reduce the disengagement of the blade 100, the wheelbase of the blade 100 is increased compared to the prior art.
[0054] To this end, the platform 18 has a downstream transverse wall 101 arranged on the downstream side of the blade 100 and an upstream transverse wall 102 opposite the downstream transverse wall 101 and arranged on the upstream side of the blade 100. The upstream and downstream sides of the blade 100 are defined with respect to the direction of hot gas flow in the impeller. Each blade 100 further has a leading edge arranged on the upstream side and a trailing edge arranged on the downstream side.
[0055] The downstream transverse wall 101 has a first circumferential edge 103 and a second circumferential edge 105 opposite the first circumferential edge 103. The first circumferential edge 103 of the downstream transverse wall 101 has a first end 107 in contact with a first rib 261 of the disc 11. The first end 107 is arranged by moving circumferentially away from the platform 18 in a first circumferential direction.
[0056] Similarly, the upstream transverse wall 102 has a first circumferential edge 104 and a second circumferential edge 106 opposite the first circumferential edge 104. The first circumferential edge 104 of the upstream transverse wall 102 has a second end 108 in contact with a second rib 262 of the disk 11 successive to the first rib 26i of the disk 11. The second end 108 is arranged by moving circumferentially away from the platform 18 in a second circumferential direction opposite to the first circumferential direction.
[0057] The first end 107 of the downstream transverse wall 101 and the second end 108 of the upstream transverse wall 102 are arranged so that a circumferential distance 110 between this first end 107 and this second end 108 is greater than an inter-rib distance 112.
[0058] The circumferential distance 110 between the first end 107 and the second end 108 is defined by the distance between the first end 107 and the projection of the second end 108 into a radial plane including the first end 107, or vice versa.
[0059] The inter-rib distance 112 is a circumferential distance between a circular center conferential 114 of the first rib 261 and a circumferential center 116 of the second rib 262. The circumferential center 114 of the first rib 26b respectively the circumferential center 116 of the second rib 262, corresponds to the intersection of a radial axis of the first rib 26b respectively of the second rib 262, and a radially external surface of the first rib 26b respectively of the second rib 262.
[0060] In one embodiment, each rib 26 has a vertex arranged radially outwards with respect to the radially external surface of the rib 26. The circumferential center 114 of the first rib 26b respectively the circumferential center 116 of the second rib 262, can correspond to the vertex of the first rib 26b respectively to the vertex of the second rib 262.
[0061] Thus, the wheelbase of the blade 100, defined by the circumferential distance 110 between the first end 107 and the second end 108, is increased compared to the prior art. This makes it possible to reduce the tilting and dislodging of the blade 100 without increasing the overall size of the blade 100 within the disk 11.
[0062] The first end 107 of the downstream transverse wall 101, respectively the second end 108 of the upstream transverse wall 102, can be arranged at a distance from the circumferential center 114 of the first rib 26b respectively from the circumferential center 116 of the second rib 262, moving away circumferentially from the platform 18. Such distances can be between 5% and 40% of the inter-rib circumferential distance, and more advantageously between 10% and 25% of the inter-rib circumferential distance.
[0063] The distance between the first end 107 of the downstream transverse wall 101 and the circumferential center 114 of the first rib 261 is substantially equal to the distance between the second end 108 of the upstream transverse wall 102 and the circumferential center 116 of the second rib 262. Alternatively, the distance between the first end 107 of the downstream transverse wall 101 and the circumferential center 114 of the first rib 261 may be different from the distance between the second end 108 of the upstream transverse wall 102 and the circumferential center 116 of the second rib 262.
[0064] In one embodiment, only one of the first end 107 of the downstream transverse wall 101 and of the second end 108 of the upstream transverse wall 102 can be arranged at a distance from the circumferential center 114 of the first rib 26i, respectively from the circumferential center 116 of the second rib 262.
[0065] The second circumferential edge 105 of the downstream transverse wall 101 has a recess or step having a shape complementary to the first circumferential edge 103. Thus, the first circumferential edge 103 of the downstream transverse wall 101 of a first blade can interlock with the second circumferential edge 105 of the downstream transverse wall 101 of a second blade adjacent to the first blade.
[0066] Similarly, the second circumferential edge 106 of the upstream transverse wall 102 has a recess or a step having a shape complementary to the first circumferential edge 104. Thus, the first circumferential edge 104 of the upstream transverse wall 102 of a first blade can fit into the second circumferential edge 106 of the upstream transverse wall 102 of a second blade adjacent to the first blade.
[0067] The step of the second circumferential edge 105 of the downstream transverse wall 101, respectively of the second circumferential edge 106 of the upstream transverse wall 102, corresponds to a recess made circumferentially inwards in the second circumferential edge 105 of the downstream transverse wall 101, respectively in the second circumferential edge 106 of the upstream transverse wall 102.
[0068] This arrangement makes it possible to reduce the size of the blades in the disk 11.
[0069] The step of the second circumferential edge 105 of the downstream transverse wall 101, respectively of the second circumferential edge 106 of the upstream transverse wall 102, may have a shape that is not complementary to the shape of the first circumferential edge 103 of the downstream transverse wall 101, respectively of the first circumferential edge 104 of the upstream transverse wall 102. In this case, the step of the second circumferential edge 105 of the downstream transverse wall 101, respectively of the second circumferential edge 106 of the upstream transverse wall 102, nevertheless has a shape that can receive the first circumferential edge 103 of the downstream transverse wall 101, respectively the first circumferential edge 104 of the upstream transverse wall 102.The step of the second circumferential edge 105 of the downstream transverse wall 101, respectively of the second circumferential edge 106 of the upstream transverse wall 102, may have, for example, a shape with dimensions greater, in particular a circumferential dimension greater, than the dimensions, in particular a circumferential dimension, of the first circumferential edges 103 and 104, so that each step can receive part or all of the first circumferential edges 105, 106.
[0070] The circumferential edges of the upstream transverse wall 102 and the downstream transverse wall 101 can be made by electro-erosion machining.
[0071] The turbine can be a high-pressure turbine or a low-pressure turbine.
[0072] The first circumferential edge 103 of the downstream transverse wall 101, respectively the first circumferential edge 104 of the upstream transverse wall 102, is inclined in the radial plane including it and extends over the entire height in the radial direction of the platform 18.
[0073] Alternatively, the first circumferential edge 103 of the downstream transverse wall 101, respectively the first circumferential edge 104 of the upstream transverse wall 102, may present any other form
[0074] Figure 6 represents another form of the circumferential edges. According to this embodiment, the first circumferential edge 103 of the downstream transverse wall 101, respectively the first circumferential edge 104 of the upstream transverse wall 102, has a projecting portion 117, respectively a projecting portion 118, comprising the first end 107, respectively the second end 108. The projecting portion 117 of the downstream transverse wall 101, respectively the projecting portion 118 of the upstream transverse wall 102, extends over a part of the radial height of the first circumferential edge 103 of the downstream transverse wall 101, respectively the first circumferential edge 104 of the upstream transverse wall 102. The projecting portions 117 and 118 each have a substantially rectangular profile in a radial plane but may have other shapes.
[0075] The step of the second circumferential edge 105 of the downstream transverse wall 101, respectively of the second circumferential edge 106 of the upstream transverse wall 102, has a complementary shape that can receive the projecting portion 117 of the downstream transverse wall 101, respectively the projecting portion 118 of the upstream transverse wall 102.
[0076] This arrangement makes it possible to obtain geometries closer to prior art designs, while maintaining an unchanged vertical orientation of the circumferential edges. The manufacture of such circumferential edges is therefore facilitated.
Claims
Demands
1. A turbine blade wheel rotating about a longitudinal axis, comprising: - a disk (11) having a plurality of cells, each cell (24) being formed by a first rib (261) and a second rib (262) successive to the disk, and - a plurality of blades (100) mounted circumferentially around said disk, each blade comprising a foot (14) engaged in a cell (24) of the disk (11), and each blade foot (14) comprising a downstream transverse wall (101) and an upstream transverse wall (102), the upstream and downstream transverse walls extending circumferentially around said blade foot (14), the downstream transverse wall (101) having a first circumferential end (107) in contact with the first rib (260) of the disk and the upstream transverse wall (102) having a second circumferential end (108) in contact with the second rib (262),in which a circumferential distance (110) between the first end (107) and the second end (108) is greater than an inter-rib circumferential distance (112).
2. Paddle wheel according to claim 1, wherein each of the first end (107) and the second end (108) is arranged respectively beyond a crest (114) of the first rib (261) and a crest (116) of the second rib (262).
3. A paddle wheel according to claim 1 or 2, wherein the downstream transverse wall (101) of at least one blade (100) has a first circumferential edge (103) comprising the first end (107) and a second circumferential edge (105) opposite the first circumferential edge (103), the second circumferential edge (105) of the downstream transverse wall (101) comprising a step configured to receive at least a portion of a first circumferential edge (103) of a blade adjacent to said blade.
4. A paddle wheel according to claim 3, wherein the first circumferential edge (103) of the downstream transverse wall (101) comprises a projecting portion (117) in a circumferential direction, said projecting portion (117) comprising the first end (107) and the notch of the second circumferential edge (105) of the downstream transverse wall (101) having a shape complementary to said portion in protrusion (117).
5. Paddle wheel according to any one of claims 1 to 3, wherein the upstream transverse wall (102) of at least one blade (100) has a first circumferential edge (104) comprising the second end (108) and a second circumferential edge (106) opposite the first circumferential edge (104), the second circumferential edge (106) of the upstream transverse wall (102) comprising a recess configured to receive at least a portion of a first circumferential edge (104) of a blade adjacent to said blade.
6. Paddle wheel according to claim 5, wherein the first circumferential edge (104) of the upstream transverse wall (102) comprises a projecting portion (118) in a circumferential direction, said projecting portion (118) comprising the second end (108) and the step of the second circumferential edge (106) of the upstream transverse wall (102) having a form complementary to said projecting portion (118).
7. A paddle wheel according to any one of claims 1 to 6 in combination with claim 3 and with claim 5, wherein a circumferential dimension of at least one of the first circumferential edge (104) of the upstream transverse wall (102) and of the first circumferential edge (103) of the downstream transverse wall (101) is between 5% and 40% of the inter-rib circumferential distance, in particular between 10% and 25% of the inter-rib circumferential distance.
8. Paddle wheel according to claim 7, wherein the circumferential dimension of the first circumferential edge (104) of the upstream transverse wall (102) is different from the circumferential dimension of the first circumferential edge (103) of the downstream transverse wall (101).
9. A paddle wheel according to any one of claims 1 to 8, wherein each blade (100) comprises a heel arranged radially externally on the periphery of said blade, the heel having two circumferential edges, and wherein one of the circumferential edges of a first blade is engaged in an adjacent circumferential edge of a second blade.
10. Turbomachine comprising at least one impeller according to any one of claims 1 to 9.