Guide vane with protrusion for compressor of a turbo engine

Description

technical field

[0001] The invention relates to the field of axial turbomachinery and in particular aircraft turbojet compressors. More specifically, the invention relates to a particular design of a blade for an axial turbomachine. Previous technique

[0002] Aerodynamic losses can occur in an axial turbomachine compressor. For example, certain interferences between the flow near the shell and the deflected flow near the blade lead to so-called "secondary" phenomena which result in losses and instabilities ("tip leakage vortex", "corner stall", ...).

[0003] To mitigate this phenomenon, different blade shapes have been developed, with for example a "sweep" or "bow" effect, extending the blade axially or circumferentially.

[0004] It is also known to incorporate protrusions on the internal or external ferrules that support the blades. This principle is often called "contouring" or "3D contouring" because it involves modifying the ferrule's outline. Rectangular or raised sections can thus be created on a flow-guiding surface between two adjacent blades.

[0005] US patent 2013 / 0101409 A1 describes a contouring example in which a protrusion is incorporated at the junction between the blade and the ferrule. Extending downstream from this protrusion, a hump is arranged on the upper surface of a blade at the trailing edge. This design nevertheless leaves room for improvement in compressor efficiency.

[0006] The published patent document US 2016 / 0024930 A1 discloses a turbomachine blade comprising at least one protrusion on the intrados side, extending from 10% to 90% of the axial chord dimension.

[0007] US document 4,720,239 A discloses turbomachine blades comprising non-uniformities that may correspond to an arrangement of downstream-oriented grooves and / or edges on the blade surfaces.

[0008] US document 2004 / 0241003 A1 describes a blade comprising a recess in the lateral pressure surface with an outer periphery disposed radially inward from the tip of the blade, and inward along the chord line from the leading edge and trailing edge.

[0009] However, the solutions disclosed by the state of the art all present room for optimization in order to further improve the efficiency of the turbomachine compressor. Summary of the invention Technical problem

[0010] The invention aims to minimize aerodynamic losses to improve the efficiency of a turbomachine, particularly at the compressor blades. Technical solution

[0011] The invention relates to a blade for an axial turbomachine compressor, comprising a leading edge, a trailing edge, an extrados surface and an intrados surface, remarkable in that the blade comprises a single irregularity in the form of a protrusion projecting from the extrados or the intrados or in the form of a recess nested in the extrados or the intrados, the irregularity having a direction of greatest dimension substantially parallel to the leading edge, the irregularity (52) having variations in thickness or depth along its direction (B) of greatest dimension and the point (E) of the irregularity (52) having the maximum thickness or depth having a radial position (RE) which is between 25 and 75% of the height (H) of the blade (26).

[0012] The irregularity can be a thickening or thinning of the blade relative to a nominal profile. The irregularity is continuous and progressive in all three spatial directions.

[0013] Since the leading edge can be curved, to describe its orientation, it may be appropriate to refer to its average direction.

[0014] The maximum thickness or depth is the greatest distance between the surface of the irregularity and the nominal theoretical surface of the upper or lower surface in the absence of the irregularity. This application will use the terms maximum thickness or depth as well as "amplitude" interchangeably.

[0015] According to an advantageous embodiment of the invention, the point of the irregularity exhibiting the maximum thickness or depth has a position along the chord, measured from the leading edge, between 0 and 30% of the chord.

[0016] According to an advantageous embodiment of the invention, the irregularity has a larger dimension direction which forms an angle between 0 and 20° with respect to the average direction of the leading edge.

[0017] According to an advantageous embodiment of the invention, the maximum thickness or depth of the irregularity, measured along the normal to the extrados or intrados, is between 1 and 15% of the thickness of the blade at the point of the irregularity exhibiting the maximum thickness or depth.

[0018] According to an advantageous embodiment of the invention, the blade comprises a foot and a head defining the radial ends of the blade, the irregularity being at a distance from the foot and the head of the blade of at least 5% of the radial height of the blade.

[0019] Thus, the irregularity is located away from the junction between the blade and the ferrule. Therefore, it does not form a continuous contour on the ferrule.

[0020] The invention also relates to a compressor blade for an axial turbomachine, comprising a leading edge, a trailing edge, an upper surface, and an lower surface, notable in that it includes a single irregularity in the form of a protrusion projecting from the upper or lower surface, or in the form of a recess embedded in the upper or lower surface. The irregularity is circumscribed to the outer radial half of the blade and has a substantially axial direction along its longest dimension. The irregularity is formed from the material of the blade and is capable of forming an air-guiding surface. The irregularity exhibits a gradual continuity of material with respect to the upper or lower surface. The maximum thickness or depth of the irregularity, measured along the normal to the upper or lower surface, is between 1 and 15% of the blade thickness at the point of the irregularity exhibiting the maximum thickness or depth.

[0021] According to an advantageous embodiment of the invention, the point of the irregularity exhibiting the maximum thickness or depth has a radial position which is between 70 and 100% of the height of the blade.

[0022] According to an advantageous embodiment of the invention, the point of the irregularity exhibiting the maximum thickness or depth has a position along the chord, measured from the leading edge, between 0 and 50% of the chord.

[0023] In other words, the irregularity is in this case mostly in the upstream part of the dawn.

[0024] According to an advantageous embodiment of the invention, the irregularity has a larger dimension direction which forms an angle between 45 and 90° with the average direction of the leading edge.

[0025] According to an advantageous embodiment of the invention, the shape factor of the irregularity is greater than two.

[0026] The shape factor is the ratio between the size of the irregularity in the direction of its largest dimension and its size in the direction of its second largest dimension. The dimensions of the irregularity can be measured curvilinearly along the extrados or intrados.

[0027] The invention also relates to a compressor blade for an axial turbomachine, the blade comprising a leading edge, a trailing edge, an upper surface, and an lower surface, notable in that it includes a single irregularity in the form of a protrusion projecting from the upper or lower surface, or in the form of a recess embedded in the upper or lower surface. The irregularity is circumscribed to the outer radial half of the blade and has a larger dimension that is substantially axial. The irregularity is formed from the material of the blade and is capable of forming an air-guiding surface. The larger dimension of this irregularity forms an angle between 45° and 90° with the average direction of the leading edge, the angle being such that the irregularity is directed away from the tip of the blade downstream.

[0028] According to an advantageous embodiment of the invention, the maximum thickness or depth of the irregularity, measured along the normal to the extrados or intrados, is between 1 and 15% of the thickness of the blade at the point of the irregularity exhibiting the maximum thickness or depth.

[0029] In practice, the magnitude of irregularities can therefore be between a few hundredths of a millimeter and 1 or 2 mm at most.

[0030] According to an advantageous embodiment of the invention, the irregularity is asymmetric, the midpoint of the irregularity in the direction of greatest dimension being preferably downstream of the point exhibiting the maximum thickness or depth and / or the irregularity comprises a plurality of points for which the thickness or depth of the irregularity is maximum.

[0031] This shape allows the flow to be gradually diverted from upstream to downstream.

[0032] Alternatively, an opposite shape may be advantageous by "over-deviating" the flow upstream and then quickly returning towards dawn downstream.

[0033] According to an advantageous embodiment of the invention, the irregularity extends primarily in a non-linear direction, possibly in an S-shape, and / or the irregularity exhibits a variation in width, and / or the irregularity forms a continuous and differentiable surface with the upper or lower surface. Thus, viewed from a circumferential direction or normal to the upper or lower surface, the irregularity may have an S-shape.

[0034] According to an advantageous embodiment of the invention, the irregularity exhibits a variation in width. The irregularity may be wider upstream than downstream, or vice versa. The difference between its upstream and downstream widths may be at least 20%.

[0035] According to an advantageous embodiment of the invention, the irregularity comprises a plurality of points for which the thickness or depth of the irregularity is maximal. Thus, the irregularity may comprise a curve or a surface parallel to the extrados or intrados, thereby forming a plateau.

[0036] According to an advantageous embodiment of the invention, the irregularity forms a continuous and differentiable surface with the extrados or intrados. Thus, there are no angular points or sharp edges, either on the irregularity itself or at the junction surface between the irregularity and the extrados or intrados, in all three spatial directions.

[0037] The invention also relates to a method for manufacturing a blade, remarkable in that it includes a step of manufacturing a blade as described above by an additive manufacturing process.

[0038] Additive manufacturing makes it possible in particular to obtain forms of irregularities that cannot be obtained by conventional processes such as plastic deformation and machining.

[0039] The invention also relates to a turbomachine compressor, comprising at least one row of rotor blades and at least one row of stator blades, the compressor being characterized in that at least one of the rotor or stator blades is according to one of the embodiments described above.

[0040] According to an advantageous embodiment of the invention, the blades are carried by an internal ferrule and / or an external ferrule, the ferrules having between two circumferentially adjacent blades a regular cylindrical or conical surface.

[0041] A regular surface is defined as a surface free of irregularities. Only the upper or lower surfaces of the blades have irregularities, but these do not form a continuous contour on a ferrule.

[0042] According to an advantageous embodiment of the invention, the compressor comprises two circumferentially adjacent blades, each having an irregularity on the extrados and intrados face opposite the other blade, the irregularity on the extrados of one of the blades forming a first surface and the irregularity on the intrados of the other blade forming a second surface, the first and second surfaces being parallel or being at least partly the image of each other by rotation around the axis of the compressor.

[0043] The invention also relates to a turbomachine, in particular an aircraft turbojet, comprising a compressor, notable in that the compressor conforms to one of the above embodiments, the compressor comprising at least: fifty, or eighty, or one hundred blades (26) according to one of the variants set out above.

[0044] In general, the advantageous modes of each object of the invention are also applicable to the other objects of the invention. Each object of the invention is combinable with the other objects, and the objects of the invention are also combinable with the embodiments of the description, which are further combinable with each other, according to all possible technical combinations, unless explicitly stated otherwise.

[0045] In particular, a blade can include several irregularities according to the variants described above on its extrados and intrados surfaces. Benefits provided

[0046] The invention allows for the reshaping of the airflow within the passage. The irregularity tends to limit airflow separation. The flow rate through the blade grid can be increased while avoiding pumping phenomena.

[0047] The invention also makes it possible to propose a simple, resistant, lightweight, economical, reliable, easy-to-produce, convenient, easy-to-maintain and easy-to-inspect solution.

[0048] The designs presented in the present invention also allow for increased mechanical and aerodynamic stability of the blade. Brief description of the drawings

[0049] There figure 1 represents an axial turbomachine according to the invention; The figure 2 is a diagram of a turbomachine compressor according to the invention; The figure 3 illustrates an isometric view of a blade according to the invention, exhibiting an irregularity on its extrados; The figure 4 presents a section of the dawn of the figure 3in a plane perpendicular to the principal direction of the dawn; The Figures 5A to 5D illustrate various examples of irregularities; The figure 6 represents a compressor section with two adjacent blades. Description of the implementation methods

[0050] In the following description, the terms "internal" and "external" refer to positioning relative to the axis of rotation of an axial turbomachine. The axial direction corresponds to the direction along the turbomachine's axis of rotation. The radial direction is perpendicular to the axis of rotation. Height refers to a radial dimension. Upstream and downstream refer to the main flow direction within the turbomachine. Length is the longest dimension of a component, and width is its second longest dimension.

[0051] It should be noted that the figures, and in particular those representing the protuberance or recess of the blade, are not drawn to scale and that the dimensions may be exaggerated to represent certain aspects of the invention more clearly.

[0052] There figure 1This simplified diagram represents an axial turbomachine. It is a turbofan engine. The turbofan 2 comprises a first compression stage, called the low-pressure compressor 4, a second compression stage, called the high-pressure compressor 6, a combustion chamber 8, and one or more turbine stages 10. In operation, the mechanical power of the turbine 10, transmitted via the central shaft to the rotor 12, drives the two compressors 4 and 6. These compressors have several rows of rotor blades associated with rows of stator blades. The rotation of the rotor around its axis of rotation 14 generates an airflow and progressively compresses this air until it enters the combustion chamber 8.

[0053] An inlet fan commonly referred to as a fan or blower 16 is coupled to the rotor 12, possibly via an epicyclic reducer (not shown), and generates an airflow which splits into a primary flow 18 passing through the various aforementioned levels of the turbomachine, and a secondary flow 20 passing through an annular duct (partially shown) along the machine and then joining the primary flow at the turbine outlet.

[0054] The secondary flow can be accelerated to generate the thrust necessary for an aircraft to fly. The primary flow 18 and secondary flow 20 are coaxial annular flows nested within each other. They are channeled through the turbomachine casing and / or the ferrules.

[0055] There figure 2 is a cross-sectional view of a compressor in an axial turbomachine such as that of the figure 1The compressor can be a low-pressure compressor 4. Part of the blower 16 and the separation nozzle 22 of the primary flow 18 and the secondary flow 20 can be observed.

[0056] The rotor 12 comprises several rows of rotor blades 24, in this case three. It may be a single-piece bladed drum, or include blades with dovetail attachments. The rotor blades 24 may extend radially from an individual platform, or from an internal ring 25 of the rotor 12.

[0057] The low-pressure compressor 4 includes several rectifiers, in this case four, each containing a row of stator blades 26. The rectifiers are associated with the fan 16 or a row of rotor blades to rectify the airflow, so as to convert the velocity of the flow into pressure, in particular into static pressure.

[0058] The stator blades 26 extend essentially radially from an outer casing 28 and can be fixed and secured to it by means of pins 30. Alternatively, the blades can be bonded. They pass radially through the primary flow 18. Their blades can pass through the annular wall of the outer casing 28. Within the same row, the stator blades 26 are regularly spaced from one another and have the same angular orientation in the flow 18. Their chords can have a fixed inclination with respect to the axis of rotation 14. Advantageously, the blades in the same row are identical and aligned. Each row of blades 26, 24 can comprise from fifty to one hundred or one hundred and twenty units.

[0059] Internal ferrules 32 can be suspended from the inner ends of the stator blades 26. The internal ferrules 32 can cooperate tightly with the rotor 12 in order to improve the compression ratio of the compressor 4.

[0060] There figure 3 sketches a first example of a blade 26 according to the invention in isometric view. The blade 26 comprises a leading edge 40, a trailing edge 42, an upper surface 44 and an lower surface 46 (not visible in the figure 3 These surfaces 44 and 46 are curved and extend from the leading edge 40 to the trailing edge 42. The blade representation is schematic, and the camber of the upper and lower surfaces is not necessarily to scale. The invention is described here specifically for a stator blade 26, but the same types of irregularities can be incorporated into a rotor blade.

[0061] The blade 26 can be considered as a stack of cambered aerodynamic profiles, whose sides generate the intrados surface 46 and the extrados surface 44. As it approaches the trailing edge 42, the contours of the profiles on the intrados and / or extrados can be parallel and / or tangent to the axis of rotation 14 of the compressor.

[0062] The leading edge 40 extends along an average direction denoted A. It can be substantially radial.

[0063] The blade 26 extends from an internal radial end called foot 48 to an external radial end called head 50 over a height H.

[0064] In this example, the blade 26 includes an irregularity 52 in the form of a protrusion on its upper surface. This protrusion extends a length L along a longer dimension B, which in this example is parallel to the axis 14. Transversely, that is, along the height of the blade 26, the protrusion 52 extends a width l. A point denoted E is the highest point of the protrusion.

[0065] The radial position of point E can be located radially with respect to the base of the blade 48 by the parameter RE. According to various embodiments of the invention, RE can be between 25 and 75% of H or between 70 and 100% of H. Other unclaimed positions are possible, for example from 0 to 30%.

[0066] A point F is at the center of the protuberance 52, that is to say it separates the protuberance 52 into two equal parts along the axis B of the length L.

[0067] Protuberance 52 is represented using contour lines to materialize its slopes.

[0068] The blade 26 is fixed at its base 48 to an internal ferrule 32. The ferrule 32 is axisymmetric. At each point of the ferrule, it has a constant radius around the axis 14. The ferrule 32 is free of irregularities. Alternatively, an irregularity such as a bump or a depression may be provided on the ferrule 32.

[0069] There figure 4 is a cross-sectional view in a plane perpendicular to direction A of the figure 3 and passing through E. For the dawn of the 26th of the figure 3 , this plan includes the line indicating direction B.

[0070] There figure 4 Figure 52 shows two examples of irregularity: a protrusion on the upper surface 44 and a recess on the lower surface 46. It is understood that the invention is not limited to this type of configuration and that both the upper surface 44 and the lower surface 46 may have none, one, or several recesses / protrusions. Furthermore, irregularities on the upper and lower surfaces are not limited to being positioned in the same plane, and for the sake of simplicity, both are shown here in the same section of the blade 26.

[0071] Point E represents the apex of irregularity 52. ​​This is at a distance e, measured normally to the extrados, e defining the thickness or amplitude of the irregularity relative to the extrados.

[0072] The irregularity extends over a length L. The length L can be measured curvilinearly along the nominal line (dotted) of the extrados 44 in the absence of irregularity.

[0073] Point F is the center of the irregularity, located halfway along its length. For some types of irregularities, points E and F may coincide.

[0074] Irregularity 52 on the intrados side 46 illustrates the depth p of a recess. The same parameters E, F, L can be used (not shown).

[0075] The chord is the segment that connects the leading edge 40 to the trailing edge 42. The length of the chord is here denoted C. The position of point E can be located on the chord by the parameter denoted here XE.

[0076] According to various embodiments of the invention, XE can be between 0 and 30% of C or between 0 and 50% of C. Other unclaimed positions are possible, for example from 50 to 70%.

[0077] THE Figures 5A to 5D These figures, viewed from a normal angle to the upper surface 44, show other examples of irregularities 52 that can be applied to the upper surface 44 or the lower surface 46 of the blade 26. Each example can be fitted to the lower or upper surface, alone or in combination with other irregularities. The shapes shown can be applied to either a protrusion or a recess. When the blade has several irregularities, these can be discontinuous or flow-through. For example, a recess can follow a protrusion or vice versa.

[0078] There figure 5Adescribes an example of irregularity 52 in the vicinity of the head 50 of the blade 26. The irregularity 52 forms an angle of about 30° with the leading edge 40 and point E is in the middle of the blade axially and is located at about 75% of the height of the blade.

[0079] There figure 5B describes an irregularity 52 which is substantially parallel to the leading edge 40. In this example, the irregularity 52 extends in height for a length of about half the height of the blade.

[0080] There figure 5C This represents another irregularity configuration, 52, which illustrates that the width of the irregularity may not be constant across its entire extent. In this example, irregularity 52 has a teardrop shape. Triangular or trapezoidal shapes are also possible. The greatest width may be found upstream or downstream.

[0081] There figure 5DThis illustrates a variant in which irregularity 52 has a principal direction that is not linear. In this specific case, the irregularity describes an S-shaped curve. Such an irregularity allows a flow to converge radially, for example in the downstream part of a compressor, before the gooseneck-shaped flow.

[0082] There figure 6 The illustration shows, in a radial projection view, two adjacent compressor blades. The blades have a protrusion and a recess 52, respectively, which are opposite each other. The geometric surfaces defined by these opposing irregularities are at least partially identical, one being the image of the other under rotation about axis 14, or under translation along an axis perpendicular to the radius. Thus, the two blades can guide the flow at least partially in the same way.

Claims

1. A blade (26) for a compressor (4, 6) of an axial turbomachine (2), the blade (26) comprising a leading edge (40), a trailing edge (42), an outer surface (44), and an inner surface (46), the blade comprising a single irregularity (52) in the form of a protrusion extending from the outer surface (44) or the inner surface (46) or in the form of a recess nestled in the outer surface (44) or the inner surface (46), characterized in that the irregularity (52) has a direction (B) of greatest dimension substantially parallel to the leading edge (40), the irregularity (52) showing variations in thickness or depth according to its direction (B) of greatest dimension, and the point (E) of the irregularity (52) with the maximum thickness or depth has a radial position (RE) that is between 25 and 75% of the height (H) of the blade (26).

2. The blade (26) according to claim 1, characterized in that the point (E) of the irregularity (52) with the maximum thickness or depth has a position (XE) along the chord, measured from the leading edge (40), between 0 and 30% of the chord (C).

3. The blade (26) according to one of claims 1 or 2, characterized in that the irregularity (52) has a direction (B) of greatest dimension forming an angle between 0 and 20° relative to the average direction (A) of the leading edge (40).

4. The blade (26) according to one of claims 1 to 3, characterized in that the maximum thickness (e) or depth (p) of the irregularity (52), measured in the normal direction to the outer surface (44) or the inner surface (46), is between 1 and 15% of the thickness of the blade (26) at the point (E) of the irregularity (52) with the maximum thickness or depth.

5. The blade (26) according to one of claims 1 to 4, characterized in that the blade (26) includes a root (48) and a tip (50) defining the radial ends of the blade (26), the irregularity (52) being located at a distance from the root (48) and the tip (50) of the blade (26) of at least 5% of the radial height (H) of the blade (26).

6. A blade (26) for a compressor (4, 6) of an axial turbomachine (2), the blade (26) comprising a leading edge (40), a trailing edge (42), an outer surface (44), and an inner surface (46), the blade comprising a single irregularity (52) in the form of a protrusion extending from the outer surface (44) or the inner surface (46) or in the form of a recess nestled in the outer surface (44) or inner surface (46), the irregularity (52) being confined to the outer radial half of the blade (26) and having a direction (B) of greatest dimension that is substantially axial, the irregularity (52) being integrally formed with the blade (26) and capable of forming an air guiding surface, characterized in that the irregularity (52) has a continuity of progressive material with respect to the outer surface (44) or the inner surface (46), the irregularity being continuous and progressive in all three directions in space, the maximum thickness (e) or depth (p) of the irregularity (52), measured according to the normal to the outer surface (44) or the inner surface (46) being between 1 and 15% of the thickness of the blade (26) at the point (E) of the irregularity (52) having the maximum thickness or depth.

7. The blade (26) according to claim 6, characterized in that the point (E) of the irregularity (52) having the maximum thickness or depth has a radial position (RE) which is between 70 and 100% of the height (H) of the blade (26).

8. The blade (26) according to claim 6 or 7, characterized in that the point (E) of the irregularity (52) having the maximum thickness or depth has a position (XE) along the chord, measured from the leading edge (40), between 0 and 50% of the chord (C).

9. The blade (26) according to one of the claims 6 to 8, characterized in that the irregularity (52) has a direction (B) of greatest dimension forming an angle between 45 and 90° with the average direction (A) of the leading edge (40).

10. A blade (26) for a compressor (4, 6) of an axial turbomachine (2), the blade (26) comprising a leading edge (40), a trailing edge (42), an outer surface (44), and an inner surface (46), the blade comprising a single irregularity (52) in the form of a protrusion extending from the outer surface (44) or the inner surface (46) or in the form of a recess nestled in the outer surface (44) or the inner surface (46), the irregularity (52) being confined to the outer radial half of the blade (26) and has a direction (B) of greatest dimension that is substantially axial, the irregularity (52) being integrally formed with the blade (26) and capable of forming an air guiding surface, characterized in that the irregularity (52) has a direction (B) of greatest dimension forming an angle between 45 and 90° with the average direction (A) of the leading edge (40), the angle being such that the irregularity (52) moves away from the blade tip downstream.

11. The blade (26) according to claim 10, characterized in that the maximum thickness (e) or depth (p) of the irregularity (52), measured according to the normal to the outer surface (44) or the inner surface (46) is between 1 and 15% of the thickness of the blade (26) at the point (E) of the irregularity (52) having the maximum thickness or depth.

12. The blade (26) according to one of claims 1 to 11, characterized in that the irregularity (52) is asymmetrical, the midpoint (F) of the irregularity (52) in the direction (B) of greatest dimension being preferably downstream of the point (E) showing the maximum thickness or depth and / or the irregularity (52) comprises a plurality of points (E) at which the thickness or depth of the irregularity (52) is maximal.

13. The blade (26) according to one of claims 1 to 12, characterized in that the irregularity (52) extends mainly in a non-linear direction (B), optionally in an S-shape and / or the irregularity (52) shows a variation in width and / or the irregularity (52) forms a continuous and derivable surface with the outer surface (44) or the inner surface (46).

14. A compressor (4, 6) for a turbomachine (2), comprising at least one row of rotor blades (24) and at least one row of stator blades (26), the compressor being characterized in that at least one of the rotor blades (24) or stator blades is according to one of claims 1 to 13.

15. The compressor (2, 4) according to claim 14, characterized in that it comprises two blades according to one of claims 1 to 13, circumferentially adjacent, and each having an irregularity (52) on the outer surface (44) and inner surface (46) facing the other blade, the irregularity (52) on the outer surface (44) of one blade forming a first surface and the irregularity (52) on the inner surface (46) of the other blade forming a second surface, the first and second surfaces being parallel or one being an image of the other by rotation about the axis (14) of the compressor (2, 4), at least in part.