Movable heel turbomachine blade

Abstract

A blade (30) having at its distal end a heel (34) comprising a first lateral edge (40) and a second lateral edge (50), each comprising a bearing surface (44, 54) and a male or female retaining member (42, 52). The first lateral edge (40) and the second lateral edge (50) of two adjacent blades are configured to maintain contact between their respective bearing surfaces (44, 54) when two adjacent blades move relative to each other between a near relative position and a far relative position in which the distance between the two adjacent blades is comparatively greater than in the near relative position, and in which the first retaining member (42) and the second retaining member (52) of adjacent blades are provided to come into contact in the far relative position so as to prevent the blades from moving apart greater than in the far position. Figure for the abstract: Fig. 3

Description

Title of the invention: Movable heel turbomachine blade technical field

[0001] The present exposition relates to a turbomachine blade. The present exposition also relates to an assembly of two blades, a wheel comprising the blade, a method for assembling a wheel, and a turbomachine comprising the wheel. Previous technique

[0002] Turbomachine blades typically have a heel having a so-called "Z-shaped" shape, i.e. comprising a male part having a substantially chevron shape with a flat and a corresponding female part, so as to maintain circumferentially the blades in position relative to each other by insertion of the male parts into the corresponding female parts.

[0003] The proper functioning of a moving wheel comprising such blades requires maintaining a certain level of mechanical clearance between the blades, so as to leave space for the thermal expansion of the parts in operation.

[0004] However, due to the circumferential mounting of the blades at their respective heels, the accumulated play around the rotating wheel results in a gap that is comparatively larger than in a rotating wheel position where the mounting of two blades is imperfect or even faulty. Due to the stresses caused by contact with abradable elements of the stator, this gap tends to increase until it causes one blade to disengage from the other circumferentially adjacent blade.

[0005] Such blade disengagement can lead to a decrease in the thermomechanical performance of the moving wheel, or even a risk of unforeseen contact and damage or breakage of the blade, which could lead to a stoppage and damage of the turbomachine.

[0006] There is therefore a need to design a blade at least partly free from the aforementioned disadvantages. Description of the invention

[0007] To this end, the present invention relates to a turbomachine blade intended to be mounted around a main axis of rotation of the turbomachine and having at its distal end a heel comprising a first circumferential end edge and a second circumferential end edge respectively configured to cooperate by complementary shape with the second circumferential end edge and the first circumferential end edge of the heel of another circumferential blade. conferentially adjacent and identical to said dawn, in which The first circumferential end edge comprises a first bearing surface and a first retention element, The second circumferential end edge comprises a second bearing surface and a second retention element, the first retention organ and the second retention organ, comprising respectively a complementary male retention organ and a complementary female retention organ, the first circumferential end edge of said blade and the second circumferential end edge of the other circumferentially adjacent blade being configured to define a translational sliding contact between the first and second bearing surfaces when said circumferentially adjacent blades move relative to each other between a near relative position and a far relative position, and in which the first retaining member of said blade and the second retaining member of the other circumferentially adjacent blade are configured to be at a distance in the near relative position and to come into contact in the far relative position.

[0008] Typically, the translational sliding contact can take place between the first and second respective bearing surfaces of said blade and of said circumferentially adjacent blade.

[0009] Typically, the first retaining member of said blade and the second retaining member of the other circumferentially adjacent blade in the distant relative position are configured to come into contact in the distant relative position so as to prevent, in the distant relative position, a relative separation of the blades.

[0010] The upstream and downstream directions are defined relative to the overall direction of fluid flow in the turbomachine when the blade is mounted in the turbomachine.

[0011] By "fluid" is meant the fluid with which the blades are intended to react, typically air or exhaust gases at various levels of temperature and pressure depending on the stage in which the blades are intended.

[0012] Typically, the overall direction of fluid flow in the turbomachine is parallel to the main axis of the turbomachine.

[0013] Typically, the main axis of the turbomachine is coincident with the axis of rotation of the turbomachine blade.

[0014] In this description, the main axis or main axis of rotation of the turbomachine is referred to as the axis of rotation of the blade when the blade is mounted in the turbomachine. The axial direction corresponds to the direction of the axis of rotation of the blade.A radial direction is a direction perpendicular to the blade's axis of rotation and intersecting that axis. Similarly, an axial plane is a plane containing the blade's axis of rotation, and a radial plane is a plane perpendicular to that axis. A circumference is understood as a circle belonging to a radial plane and whose center lies on the blade's axis of rotation. A tangential or circumferential direction is a direction tangent to a circumference; it is perpendicular to the blade's axis of rotation but does not pass through it. A tangential or circumferential plane is a plane strictly parallel to the blade's axis of rotation, that is, it does not intersect or include this axis. An axial or radial section corresponds, respectively, to a section along an axial plane or along a radial plane.Hereafter, a plane slightly inclined with respect to a radial or circumferential plane will be designated respectively as a substantially radial plane or a substantially circumferential plane. The terms "interior" and "exterior" and their derivatives are defined with respect to the principal axis.

[0015] Such a structure has the double advantage of allowing a certain latitude of movement between two circumferentially adjacent blades, while preventing the disengagement of these blades.

[0016] In particular, such a structure allows the parts to expand freely during operation and permits small amplitude movements.

[0017] The assembly of the moving wheel is thus made easier, and the risks of damage during operation are reduced.

[0018] Typically, the first retaining member and the second retaining member of the circumferentially adjacent blades are configured to only come into contact in the distant relative position.

[0019] Typically, the transition from the near relative position to the far relative position is achieved by circumferential relative displacement of the heels around the main axis, or in a circumferential plane, in particular a substantially circumferential plane. For example, the transition from the near relative position to the far relative position is achieved by displacement of the heels in the plane of the blade platforms.

[0020] Typically, the first bearing surface includes a cavity suitable for receiving the second retention member.

[0021] Typically, at least one of the first retention organ and the second retention organ has a triangular or rectangular shape.

[0022] For example, the first retention organ and the second retention organ have a triangular shape. For example, the first retention organ and the second retention organ have a rectangular shape.

[0023] Typically, the awl is made in one piece.

[0024] The present invention also relates to an assembly comprising a first blade according to the present invention and a second blade according to the present invention.

[0025] In such an assembly, the first blade and the second blade are typically identical, and the first lateral edge of the first blade is configured to cooperate by complementarity of form with the second lateral edge of the first blade.

[0026] Typically, the first blade and the second blade are mounted circumferentially adjacent around the main axis.

[0027] The present invention also relates to a movable wheel comprising a plurality of blades according to the present invention, circumferentially assembled to the circumferentially adjacent blades of the plurality of blades.

[0028] Typically, the rotating wheel comprises a disc having recesses on its outer periphery in which the blades are mounted. Typically, the blades are mounted by their respective feet.

[0029] The present invention also relates to a method of assembling a movable wheel according to the present invention, comprising a step of applying a pre-torsion force to the first blade and positioning the first blade circumferentially adjacent to a second blade so as to bring the first bearing surface of one into contact with the second bearing surface of the other circumferentially adjacent blade.

[0030] The present invention also relates to a turbomachine comprising the moving wheel according to the present invention. Brief description of the drawings

[0031] The purpose of this presentation and its advantages will be better understood upon reading the detailed description below of various embodiments given by way of non-limiting examples. This description refers to the attached figure pages, on which:

[0032] [Fig-1] Fig. 1 represents a simplified and partial schematic view of a turbo aircraft engine with fan according to an axial cross-section;

[0033] [Fig.2] Fig.2 represents a schematic cross-sectional view of a turbojet blade according to an embodiment of the invention.

[0034] [Fig.3] The [Fig.3] represents a schematic view of a blade according to a first embodiment, seen in the section plane III of the [Fig.2].

[0035] [Fig.4] The [Fig.4] represents an assembly of two blades according to a first embodiment, seen in the section plane III of the [Fig.2].

[0036] [Fig.5A][Fig.5B] Figures 5A and 5B represent an assembly of two blades according to the first embodiment, respectively in close relative position and in distant relative position, according to an enlargement V of [Fig.4].

[0037] [Fig. 6A][Fig. 6B] Figures 6A and 6B represent an assembly of two blades according to a second embodiment, respectively in a close relative position and in a relatively distant position, according to the enlargement V of [Fig.4].

[0038] [Fig.7A][Fig.7B] Figures 7A and 7B represent an assembly of two blades according to a third embodiment, respectively in close relative position and in distant relative position according to the enlargement V of [Fig.4]. Description of the implementation methods

[0039] Figure 1 shows an example of a mixed-flow turbojet engine 10 having a principal axis of rotation A represented by a dashed line. The airflow in the turbojet engine 10 is shown in the diagram from left to right. The inlet of the turbojet engine 10 has a fan 11 that draws air into the turbojet engine 10. The airflow is then divided into a primary airflow and a secondary airflow. The primary airflow is compressed successively by a low-pressure compressor 12 and a high-pressure compressor 13, driven respectively by a low-pressure turbine 16 and a high-pressure turbine 15. Between the compressors 12, 13 and the turbines 15, 16 is a combustion chamber 14 that receives the air compressed by the compressors 12, 13 and into which the fuel is injected to carry out combustion.The combustion gases exit the combustion chamber 14, driving the turbines 15 and 16, and join the secondary airflow, which flows through the turbojet 10 on the radial periphery of the primary airflow. The combustion gases exiting the turbines 15 and 16 are then ejected from the turbojet 10 through the nozzle 17, at the distal end of the turbojet 10.

[0040] Blade structures 30, and in particular blade heel 34 30, will be described below with reference to the view in [Fig.2] and the cross-sectional views in Figures 3 to 7B.

[0041] The blade 30 will be described in an orthogonal frame formed of a first direction X, a second direction Y and a third direction Z, where the first direction X is a direction of rotation of the blade and where the second direction Y is a circumferential direction.

[0042] In particular, the blade 30 mounted in the low-pressure turbine 16 will be described, that is to say, in which the first direction X is parallel to the main axis A, in which the second direction Y is a circumferential direction of the turbine 16, and in which the third direction Z is a radial direction of the blade.

[0043] Typically, the first direction X is oriented from upstream to downstream, so that in Figures 1 and 2, the upstream to downstream direction corresponds to a left to right direction.

[0044] Typically, [Fig.2] is a schematic view of a blade 30 in section along an axial plane.

[0045] The blade 30 includes a blade foot 36 at a proximal or radially inner end and by which the blade 30 can be mounted on an inner housing (not re- presented), as well as a heel 34 at a distal or radially external end.

[0046] The heel 34 is typically intended to face a housing 20, for example an abradable element 22 of the housing 20.

[0047] The blade 30 also includes a blade 32, extending between the blade foot 36 and the heel 34 and suitable for exchanging mechanical power with the fluid.

[0048] The blade 30 typically includes sealing blades 34a, for example two blades substantially aligned along the first direction X.

[0049] Typically, the licks 34a are part of the heel 34 of the dawn 30, and extend from a platform 34b of the heel 34.

[0050] The blades 34a are mounted radially opposite the housing 20, in particular the abradable element 22 of the housing 20, so as to reduce the flow of fluid leaking around the blade 30 associated with a decrease in the mechanical power extracted from the fluid.

[0051] The heel 34 of the blade 30 can be formed in one piece. In particular, the blade 30 can be formed in one piece.

[0052] The licks 34a extend in a substantially radial direction, that is to say a direction having a non-zero component along the third direction Z.

[0053] The platform 34b extends in a substantially radial plane.

[0054] The structure of the heel 34, and more particularly of the platform 34b, will be described in more detail with respect to section plane III of [Fig.2], corresponding to the mean plane of the platform 34b, that is to say the plane equidistant between the radially inner and outer faces of the platform 34b.

[0055] A first embodiment of the blade 30 will be described in detail with respect to figures 3, 4, 5A and 5B.

[0056] For the sake of simplicity of representation, in the example of Figures 4, 5A and 5B, two identical blades 30 will be described rather than one in order to illustrate the blade retention mechanism. It is understood that the characteristics defined with respect to either blade 30 may be the characteristics of a single blade 30 according to the invention.

[0057] In particular, a male part of a blade 30 and a female part of another blade 30 will be described, the blades 30 each carrying said male and female parts.

[0058] The heel 34 comprises a first circumferential end edge 40 and a second circumferential end edge 50.

[0059] The first circumferential end edge 40 and the second circumferential end edge 50 are designed to cooperate with each other by complementary shape, so that they can be assembled. Typically, the first circumferential end edge 40 is a male circumferential end edge, designed to cooperate by complementary shape with the second circumferential end edge 50. of an adjacent dawn 34.

[0060] Such a complementarity of form makes it possible to make the circumferentially adjacent blades 30 jointly connected to each other.

[0061] For example, as shown in Figures 3 and 4, the first circumferential end edge 40 has an overall chevron shape including a flat (Z-shape), allowing the creation of contact areas to keep the blades 30 circumferentially aligned.

[0062] The first circumferential end edge 40 and the second circumferential end edge 50 comprise respectively a first bearing surface 44 and a second bearing surface 54, configured to be in contact with each other. The first bearing surface 44 and the second bearing surface 54 are typically in translational sliding contact.

[0063] Typically, the blades 30 are mounted relative to each other in pretorsion along their length direction, i.e. along the third direction Z, so that the circumferentially adjacent blades 30 are supported against each other through their respective first bearing surface 44 and second bearing surface 54.

[0064] The first circumferential end edge 40 and the second circumferential end edge 50 comprise respectively a first retention member 42 and a second retention member 52, which will be described in more detail with respect to Figures 5A and 5B, representing an enlargement of area V of [Fig.4] comprising the lateral edges 40,50 of two circumferentially adjacent blades 30.

[0065] Fig. 5A represents the blades 30 in a position called "close position" or "relative close position", and Fig. 5B represents the blades 30 in a position called "distant position" or "relative distant position", it being understood that the qualifiers "close" and "distant" are understood relative to each other.

[0066] In a close relative position, on [Fig.5A], the circumferentially adjacent blades 30 are supported against each other by their bearing surfaces 44, 54.

[0067] The torsional force, which tends to press the blades 30 against each other at the level of the support surfaces 44, 54, tends to constrain the relative displacement of the blades 30 with respect to each other to a translation along a direction t transverse to the support surfaces 44, 54 and included in the plane of the platforms 34b, substantially circumferential.

[0068] Generally speaking, "near," "far," or any associated term refers here to proximity or distance along the transverse direction t. In particular, "near" or "far" does not define the presence or absence of contact between the blades 30, it being understood that the blades 30 may be closer or farther apart. one of the other although in contact at the level of their bearing surfaces 44, 54.

[0069] The first retention member 42 is typically a male retention member, for example projecting from the first bearing surface 44. The first retention member 42 has, for example, a crenellated shape.

[0070] The second retention organ 52 is typically a female retention organ, for example having the shape of a cavity capable of receiving the first retention organ 42.

[0071] Typically, the relative dimensions of the first retention member 42 and the second retention member 52 are provided so that in a close relative position, the retention members 42, 52 are not in contact with each other.

[0072] Typically, the width of the second retention member 52 measured along the direction t is greater than the width of the first retention member 42 measured along the direction t.

[0073] Typically, the height of the second retention member 52 measured along the direction t is greater than the height of the first retention member 42 measured perpendicular to the direction t.

[0074] Such an arrangement allows a certain level of displacement along the direction t. In particular, the blades 30 can move away from each other along a direction t to the distant relative position.

[0075] In a relatively distant position, the retention members 42,52 come into contact with each other so as to prevent any further relative separation of the blades 30.

[0076] The distant relative position typically corresponds to an assembly position, that is, a relative configuration of two adjacent blades 30 during assembly. The contact between the retaining elements 42, 52 thus ensures that the blades are held in pairs.

[0077] This support makes it easier to assemble by reducing the risk of blades 30 coming apart.

[0078] This support also helps to prevent incorrect relative positioning of the blades 30 with respect to each other during operation of the tur-bomachine.

[0079] The close relative position typically corresponds to an operating position, that is, a relative configuration of two circumferentially adjacent blades 30 during operation. The retaining devices 42, 52 are thus kept at a distance, thereby reducing the risk of degradation of the retaining devices 42, 52 as well as the risk of transmission of parasitic forces between the blades.

[0080] Typically, a lateral surface 42a of the first protruding retaining member 42 bears against a corresponding lateral surface 52a of the second member retention 52.

[0081] The first retention member 42 extends, forming an angle 01 with the first bearing surface 44, for example equal to 90°.

[0082] Typically, angle 01 is measured between the lateral surface 42a and the bearing surface 44.

[0083] The second retention member 52 extends, forming an angle 02 with the second bearing surface 54, for example equal to 90°.

[0084] Typically, angle 02 is measured between the lateral surface 52a and the bearing surface 54.

[0085] Typically, angle 01 and angle 02 are equal.

[0086] Such orientations of lateral surfaces 42a, 52a of the retention members 42, 52, make it possible to obstruct a displacement along the direction t.

[0087] Angles 01 and 02 can be acute angles, i.e. less than 90°. In this way, the normal reaction force on the surfaces tends to press the blades 30 against each other.

[0088] The blades 30 can then move relative to each other between the near relative position and the far relative position. In particular, the blades 30 are constrained to move only between the near relative position and the far relative position.

[0089] For example, a contact (not shown) between the first circumferential end edge 40 and the second circumferential end edge 50 can prevent movement beyond the near relative position.

[0090] The contact in close relative position can for example take place by contact between two or more surfaces of the lateral edges 40,50, for example by insertion by matching shape of the lateral edges 40,50 into each other.

[0091] The contact between the retention members 42, 52 can prevent movement beyond the distant relative position, and in particular the contact between the lateral surfaces 42a,52a of the retention members 42, 52.

[0092] The displacement amplitude ô between the near relative position and the far relative position is measured along the direction t.

[0093] With the lateral surfaces 42a, 52a in contact in a distant relative position, the distance between the lateral surfaces 42a, 52a measured along the direction t in a close relative position is equal to the displacement amplitude ô, represented on [Fig.5A].

[0094] Typically, the retention members 42,52 are designed to only come into contact in the distant relative position.

[0095] Such a structure makes it possible in particular to reduce the risks of wear and damage to the retention devices 42, 52, by any known mode of wear or damage, including abrasion, fatigue or brittle breakage.

[0096] Such a structure then makes it possible to ensure the functions of maintaining the blades 30 relative to each other, while allowing a certain play between the blades 30 and thus a certain level of tolerance.

[0097] For the purposes of illustration, the blades 30 have been described in a simplified mode of translational displacement along rectilinear support surfaces 44, 54.

[0098] On the one hand, it is understood that the bearing surfaces 44, 54 are not necessarily rectilinear, in which case the contact between the bearing surfaces 44, 54 is not surface contact (or linear contact as seen in plane V) but linear contact (or point contact as seen in plane V). In such a case, the direction t is curvilinear and the displacement amplitude ô is measured along the curvilinear direction t.

[0099] On the other hand, it is understood that the distance between the blades 30 is not only restricted when the bearing surfaces 44, 54 are in surface contact.

[0100] For example, the torsion of the blades can lead to the formation of a small angle between the bearing surfaces 44, 54.

[0101] Due to the height of the retention members 42,52, the function of preventing greater distance can always be ensured despite imperfect contact between the members 42, 52.

[0102] The first retention member 42 and the second retention member 52 may have a rectangular shape. Typically, the second retention member 52 has a rectangular notch shape corresponding to the shape of the first retention member 42.

[0103] A second embodiment will be described with respect to Figures 6A and 6B, and a third embodiment will be described with respect to Figures 7A and 7B.

[0104] Fig. 6A represents blades 30 according to a second embodiment in a close relative position, and Fig. 6B represents blades 30 according to a second embodiment in a distant relative position.

[0105] Fig.7A represents blades 30 according to a third embodiment in a close relative position, and Fig.7B represents blades 30 according to a third embodiment in a distant relative position.

[0106] Elements common to the first, second and third embodiments will not be described again, and identical or similar components will be designated by numerical references incremented by 100 or 200.

[0107] The second and third embodiments differ from the first embodiment in the form of the first retention members 152,252 respectively and the second retention members 242,252 respectively.

[0108] As shown in Figures 6A and 6B, the first retention member 142 may have a triangular shape, of which a first surface is the lateral surface 142a and a second surface is slightly inclined with respect to the bearing surface 142.

[0109] The second retention member 152 can then have a shape corresponding to the shape of the first retention member 142, that is to say a corresponding triangular notch shape.

[0110] As shown in Figures 7A and 7B, the first retention member 242 may have a walking shape.

[0111] The second retention member 152 can then have a shape corresponding to the shape of the first retention member 142, that is to say a step shape, for example a step of greater height.

[0112] Such structures make it possible, for example, to increase the mechanical resistance of the retention devices, in particular of the first retention device 142, 242.

[0113] For example, such structures make it possible to reduce the stress concentration due to the support between the first and second retention members.

[0114] Two blades 30 thus formed can be mounted circumferentially against each other so as to form an assembly.

[0115] For example, a pre-torsion force can be applied to one of the blades 30 before positioning it circumferentially adjacent to the other of the blades 30 so as to bring their respective bearing surfaces 44,54,144,154,244,254 into contact.

[0116] In particular, a plurality of blades 30 thus formed can be circumferentially assembled to each of the circumferentially adjacent blades 30 of the plurality of blades 30 so as to form a movable wheel.

[0117] A pre-torsion force can then be applied to each of the blades 30 of the plurality of blades 30 before positioning it circumferentially adjacent to another blade 30.

[0118] 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 a restrictive sense.

[0119] Typically, the above embodiments have been described in the case where the first circumferential end edge 40 is a male circumferential end edge, the first retention organ 42 is a male organ, the second circumferential end edge 50 is a female circumferential end edge and the second retention organ 52 is a female organ.

[0120] It is understood that any male / female combination is possible among the four combinations: first circumferential end edge 40 male or female and second circumferential end edge 50 corresponding between male or female, first retention organ 42 male or female and second retention organ 52 corresponding between male or female.

Claims

Demands

1. Turbomachine blade (30) intended to be mounted around a main axis (A) of rotation of the turbomachine and having at its distal end a heel (34) comprising a first circumferential end edge (40) and a second circumferential end edge (50) respectively configured to cooperate by complementary shape with the second circumferential end edge (50) and the first circumferential end edge (40) of the heel (34) of another circumferentially adjacent blade identical to said blade (30), in which the first circumferential end edge (40) comprises a first bearing surface (44) and a first retaining member (42), the second circumferential end edge (50) comprises a second bearing surface (54) and a second retaining member (52),the first retaining member (42) and the second retaining member (52) respectively comprising a complementary male retaining member and a complementary female retaining member, the first circumferential end edge (40) of said blade (30) and the second circumferential end edge (50) of the other circumferentially adjacent blade being configured to define a translational sliding contact between the first (44) and second (54) bearing surfaces when said circumferentially adjacent blades move relative to each other between a near relative position and a far relative position, and wherein the first retaining member (42) of said blade (30) and the second retaining member (52) of the other circumferentially adjacent blade are configured to be apart in the near relative position and to come into contact in the far relative position.

2. Blade according to claim 1, wherein the first retaining member (42) and the second retaining member (52) of the circumferentially adjacent blades are configured to come into contact only in the distant relative position.

3. Blade according to claim 1 or 2, wherein the transition from the near relative position to the far relative position is achieved by circumferential relative displacement of the heels (34) around the main axis (A).

4. Blade according to any one of claims 1 to 3, wherein the first bearing surface (44) includes a cavity suitable for receiving the second retention device (52).

5. Blade according to any one of claims 1 to 4, wherein at least one of the first retaining member (42) and the second retaining member (52) has a triangular or rectangular shape.

6. Blade according to any one of claims 1 to 5, made in one piece.

7. Assembly comprising a first blade according to any one of claims 1 to 6 and a second blade according to any one of claims 1 to 6, the first and second blades being mounted circumferentially adjacent around the main axis (A).

8. Moving wheel comprising a plurality of blades according to any one of claims 1 to 6, circumferentially assembled to the circumferentially adjacent blades of the plurality of blades.

9. Method of assembling a movable wheel according to claim 8, comprising a step of applying a pre-torsion force to a first blade and positioning the first blade circumferentially adjacent to a second blade so as to bring the first bearing surface (44) of one into contact with the second bearing surface (54) of the other circumferentially adjacent blade.

10. Turbomachine comprising a movable wheel according to claim 8.

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