Rectifier blade with a slot
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2023-11-03
- Publication Date
- 2026-05-22
Abstract
Description
Title of the invention: Rectifier blade with a slot Technical field
[0001] This disclosure relates to the general field of aircraft turbomachines and more particularly to turbomachine casing rectifiers.
[0002] The present disclosure relates more particularly, but not exclusively, to exhaust casing rectifier vanes. STATE OF THE ART
[0003] The operation of a turbomachine causes a flow of air to circulate in the turbomachine between moving rotor blades and stator blades or casing rectifier blades.
[0004] The casing rectifier vanes having a fixed orientation relative to the casing, the air flow has an angle of incidence relative to the vanes which changes between different operating speeds of the turbomachine.
[0005] The change in the angle of incidence of the air flow in the turbomachine relative to the casing blades induces a separation of the air flow downstream of the blades in certain operating regimes.
[0006] The separation of the air flow downstream of the blades generates aerodynamic losses and / or pressure losses which results in a reduction in the performance of the turbomachine. GENERAL STATEMENT
[0007] One aim of the disclosure is to solve the problem of separation of the air flow from the rectifier blades regardless of the operating speed of the turbomachine.
[0008] For this purpose, according to one aspect of the present disclosure, a turbomachine rectifier assembly in which an air flow circulates is proposed. The assembly comprises:
[0009] - an internal shell extending along a longitudinal axis XX,
[0010] - an outer shell radially external to the inner shell, and
[0011] - a rectifier vane extending radially from the inner shroud to the shroud external, the rectifier blade comprising a leading edge and a trailing edge downstream of the leading edge in the direction of circulation of the air flow, and an extrados wall and a intrados wall extending respectively from the leading edge to the trailing edge.
[0012] The rectifier blade further comprising a through slot formed at least partially in the extrados wall and extending over the entire height of the rectifier blade.
[0013] The slot formed in the blade makes it possible to prevent the air flow from separating from the extrados wall of the blade, whatever the operating speed of the turbomachine, in other words, whatever the angle of incidence of the air flow relative to the blade.
[0014] Furthermore, such a slot formed in the casing blade makes it possible to improve the aerodynamic performance of the turbomachine regardless of the operating speed of the turbomachine and without impacting the operating speeds in which the separation of the air flow was non-existent on a blade without a slot.
[0015] Advantageously, but optionally, the assembly described comprises at least one of the following characteristics, taken alone or in any combination:
[0016] - the slot comprises an inlet and an outlet, the outlet opening onto the extrados wall and being downstream from the inlet in the direction of airflow circulation;
[0017] - the leading edge is formed by an upstream point of each axial section of the blade of a rectifier for which the radius of curvature is minimal and the trailing edge is formed by a downstream point of each axial section of the rectifier blade for which the radius of curvature is minimal;
[0018] - the slot cuts the rectifier blade into a main part, comprising the edge of leak, and a secondary portion and wherein the slot comprises a main wall common with the main portion and a secondary wall common to the secondary portion;
[0019] - at the entrance of the slot, the main wall of the slot has, in an axial plane, a first direction forming an angle of 45° + / - 25° relative to a second direction orthogonal to a master torque of an axial section of the rectifier blade;
[0020] - the inlet is at a distance from the leading edge of + / -10% of a curvilinear length from the intrados wall from the leading edge to the trailing edge;
[0021] - at the exit, the main wall has a continuity in tangency with the wall extrados of the rectifier blade;
[0022] - the exit is at a distance from the leading edge of between 20 and 60% of a curvilinear distance of the extrados wall from the leading edge to the trailing edge;
[0023] - the slot has a width equal to the diameters of circles inscribed in the slot, each inscribed circle being tangent to the main wall and to the secondary wall, the width of the outlet being equal to or less than the width of the inlet;
[0024] - the assembly comprises several rectifier vanes each comprising the pre-slot previously described.
[0025] According to another aspect, a turbomachine is provided comprising an exhaust casing formed by the assembly previously described.
[0026] According to another aspect, there is provided an aircraft comprising the previously described turbomachine. DESCRIPTION OF FIGURES
[0027] Other features, aims and advantages will emerge from the following description, which is purely illustrative and not limiting, and which must be read in conjunction with the attached drawings in which:
[0028] [Fig.l] illustrates an aircraft schematically.
[0029] [Fig.2] illustrates a schematic sectional view of an aircraft propulsion unit.
[0030] [Fig. 3] illustrates a perspective view of a portion of an exhaust casing, according to an embodiment of the present disclosure.
[0031] Figures 4a and 4B illustrate a section of a slotless stator blade and a slotted stator blade, according to an embodiment of the present disclosure.
[0032] [Fig.5] illustrates a perspective view of a rectifier vane with a slot, according to an embodiment of the present disclosure.
[0033] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION Aircraft
[0034] An aircraft 100, as illustrated for example by [Fig.l], is an apparatus configured to rise and move in the air, and may, for example, be an airplane, civil or military, or even a helicopter. An aircraft 100 comprises an airframe which, in the case of an airplane, is composed of a fuselage, a wing structure comprising two wings, empennages, flight control surfaces and landing gear. Propulsion unit
[0035] A propulsion unit 1, as illustrated, for example, by [Fig. 2], comprises an engine 2 (or turbomachine) and possibly a nacelle 3, in the embodiment of a ducted engine. The propulsion unit 1 has a main direction extending along a longitudinal axis XX. The propulsion unit 1 is configured to be fixed to the airframe of the aircraft 100, for example under its wings, in the case of an airplane, and this by means of a pylon (or mast). The propulsion unit 1 can also be mounted on the wing of the airplane or at the rear of its fuselage, or even be integrated into its fuselage.
[0036] The engine 2 may be a twin-spool, twin-flow, direct-drive ducted turbojet engine, as described below, but may also have a different number of spools and / or flows, and / or be another type of turbojet engine, such as a geared turbojet engine or a turboprop, with or without afterburner, ducted or unducted.
[0037] Unless otherwise specified, the terms “upstream” and “downstream” are used with reference to the overall direction of airflow through the propulsion unit 1 in operation. Similarly, an axial direction corresponds to the direction of the longitudinal axis XX and a radial direction is a direction perpendicular to the axis Ion- gitudinal XX and intersecting the longitudinal axis XX. Furthermore, an axial plane is a plane containing the longitudinal axis XX and a radial plane is a plane perpendicular to the longitudinal axis XX. A circumference is understood as a circle belonging to a radial plane and whose center belongs to the longitudinal axis XX. A tangential or circumferential direction is a direction tangent to a circumference: it is perpendicular to the longitudinal axis XX but does not pass through the longitudinal axis XX. Finally, the adjectives "inner" (or "internal") and "outer" (or "external") are used in reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the longitudinal axis XX than the outer part of the same element. The engine
[0038] The engine 2 comprises, from upstream to downstream, a fan 20, a motor casing 21, a compressor section 22, comprising a low pressure compressor 220 and a high pressure compressor 221, a combustion chamber 23, a turbine section 24, comprising a high pressure turbine 240 and a low pressure turbine 241, and an exhaust casing 25.
[0039] The compressor section 22 comprises a succession of stages each comprising a wheel of moving blades (rotor) rotating in front of a wheel of fixed blades (stator). The turbine section 24 also comprises a succession of stages each comprising a wheel of fixed blades (stator) behind which a wheel of moving blades (rotor) rotates.
[0040] The fan 20, the rotor part of the low-pressure compressor 220, and the rotor part of the low-pressure turbine 241 are connected to each other by a low-pressure shaft 27 extending along the longitudinal axis XX, thus forming a low-pressure body. The rotor part of the high-pressure compressor 221 and the rotor part of the high-pressure turbine 240 are connected to each other by a high-pressure shaft 28 extending along the longitudinal axis XX, thus forming a high-pressure body. The low-pressure shaft 27 is generally housed, over a section of its length, in the high-pressure shaft 28 and is coaxial with the high-pressure shaft 28.
[0041] The compressor section 22, the combustion chamber 23 and the turbine section 24 are surrounded by the engine casing 21, to which the stator parts of the low pressure compressor 220, the high pressure compressor 221, the high pressure turbine 240 and the low pressure turbine 241 are connected.
[0042] The engine casing 21 defines a primary vein A in which the rotor and stator parts of the low-pressure compressor 220, the high-pressure compressor 221, the low-pressure turbine 241 and the high-pressure turbine 240 extend. The primary vein A passes right through the engine casing 21. The stator parts in the primary vein A can thus form rectifiers (or OGV for “Outlet Guide Varies" in English terminology). In this way, the air flow circulating in the primary vein A is deflected by the rotating rotor parts and is straightened by the stator parts fixed relative to the motor casing 21 defining the primary vein A.
[0043] The exhaust casing 25 is connected to the engine casing 21 downstream of the turbine section 24. The exhaust casing 25 is fixedly mounted on the engine casing 21. The exhaust casing 25 is described in more detail below.
[0044] The longitudinal axis XX defines the axis of rotation for the fan 20, the rotor parts of the compressor section 22 and the rotor parts of the turbine section 24, in other words for the low pressure body and the high pressure body which are each capable of being driven in rotation about the longitudinal axis XX relative to the engine casing 21.
[0045] In the embodiment of a ducted engine, the nacelle 3 extends radially outside the engine 2, all around the longitudinal axis XX, so as to surround both the engine casing 21, and to define a secondary vein B with the engine casing 21. The upstream part of the nacelle 3 further defines an air flow inlet through which the fan 20 sucks in the air flow circulating through the propulsion unit 1. The nacelle 3 is attached and fixed to the aircraft 100 by means of the mast.
[0046] In operation, the fan 20 draws in an air flow, a portion of which, circulating within a primary vein A passing right through the engine casing 21, is successively compressed within the compressor section 22, ignited within the combustion chamber 23 by combustion of fuel, and expanded within the turbine section 24 before being ejected from the engine 2 by passing through the exhaust casing 25. Another portion of the air flow can circulate within the secondary vein B which takes an elongated annular shape surrounding the engine casing 21 and then the exhaust casing 25. In this way, the propulsion unit 1 generates thrust. This thrust can, for example, be used for the benefit of the aircraft 100 on which the propulsion unit 1 is attached and fixed. The exhaust casing
[0047] The exhaust casing 25, as illustrated, for example, by [Fig. 3], comprises an inner shell 29 and an outer shell 30. The inner shell 29 comprises an outer wall 290 and the outer shell 30 comprises an inner wall 300. The outer wall 290 of the inner shell 29 and the inner wall 300 of the outer shell 30 define in the exhaust casing 25 the extension of the primary vein A of the engine casing 21 towards the outlet of the engine 2.
[0048] The exhaust casing 25 comprises arms 31 having an aerodynamic profile. The arms 31 extend radially in the primary vein A of the inner shell 29 and preferably as far as the outer shell 30. The arms 31 form rectifiers distributed circumferentially all around the longitudinal axis XX. Subsequently, the arms 31 of the exhaust casing 25 and possibly also the stator vanes previously described will be called a rectifier vane or simply a vane, for simplicity. Furthermore, in general, an assembly formed by an internal shell, fixed vanes, called rectifier vanes, and possibly an external shell, can be called a rectifier assembly. Crankcase arm
[0049] According to an embodiment illustrated by [Fig. 3], the blade 31 comprises a root 32 and a head 33. The root 32 is connected to the internal shroud 29. Advantageously, the head 33 of the blade 31 is connected to the external shroud 30. The blade 31 thus comprises a height h between the root 32 and the head 33.
[0050] Each blade 31 comprises a leading edge 34 and a trailing edge 35 in the direction of circulation of the air flow. The leading edge 34, as illustrated, for example, by [Fig.4a], is formed by an upstream point of each axial section 36 of the blade 31 for which the radius of curvature is minimal. The trailing edge 35 is formed by a downstream point of each axial section 36 of the blade 31 for which the radius of curvature is minimal.
[0051] The blade 31 comprises an extrados wall 37 and a intrados wall 38. The extrados wall 37 and the intrados wall 38 extend from the root 32 to the head 33 of the blade 31 and from the leading edge 34 to the trailing edge 35. Thus the extrados wall 37 and the intrados wall 38 meet at the leading edge 34 and the trailing edge 35. The extrados wall 37 comprises a surface greater than the surface of the intrados wall 38.
[0052] The section 36 of the blade 31 along an axial plane PP orthogonal to the radial direction of the blade 31 therefore comprises a leading point 340, a vanishing point 350, a curved extrados line 370, connecting the leading point 340 and the vanishing point 350, and a curved intrados line 380, also connecting the leading point 340 and the vanishing point 350.
[0053] The leading point 340 is the intersection 36 between the leading edge 34 and the axial plane PP, and the trailing point 350 is the intersection 36 between the trailing edge 35 and the axial plane PP. The extrados line 370 is the intersection 36 between the extrados wall 37 and the axial plane PP, and the intrados line 380 is the intersection 36 between the intrados wall 38 and the axial plane PP. The extrados line 370 comprises a curvilinear length from the leading point 340 to the trailing point 350 greater than a curvilinear length of the intrados line 380 from the leading point 340 to the trailing point 350.
[0054] The section 36 of the blade 31 also comprises a median 39 and a master couple 40. The median 39 is a line connecting the leading point 340 and the trailing point 350 of the section 36 passing at an equal distance from the extrados line 370 and the intrados line 380. The master couple 40 of the section 36 is the segment, perpendicular to the median 39, the longest connecting a point on the extrados line 370 and a point on the line intrados 380.
[0055] The blade 31 having a profiled shape, what has been described for a section 36 of the blade 31 applies to each of the axial sections 36 of the blade 31. For the sake of simplicity, we will simply refer hereinafter to the median 39 and the master section 40 of the blade 31. The median 39 of the blade 31 is the surface formed by the median 39 of each section 36 of the blade 31 and the master section 40 of the blade 31 is the surface formed by the master section 40 of each section 36 of the blade 31. Slot in the arm
[0056] Depending on the operating speeds of the engine 2, the circulation of the air flow in the primary vein A is modified. For example, between a start-up speed (or "take-off" according to English terminology) or a cruise speed (or "cruise" according to English terminology), the circulation of the air flow in the primary vein A, and therefore the angle of incidence relative to the blades 31, may be different.
[0057] Preferably, a blade 31 of the exhaust casing 25 comprises a slot 5, as illustrated, for example, by [Fig.4b]. The slot 5 is configured to deflect a portion of the air flow circulating in the primary vein A and arriving at the blade 31 and thus prevent the air flow from separating downstream of the blade 31 regardless of the operating speed of the engine 2.
[0058] Advantageously, several blades 31 of the exhaust casing 25 each comprise a slot 5. Optionally, all the arms of the exhaust casing 25 and / or some or all of the blades 31 of the compressor section 22 and of the turbine section 24 each comprise a slot 5.
[0059] The slot 5 of the blade 31, as illustrated, for example, by [Fig. 5], extends radially and uniformly from the root 32 of the blade 31 to the head 33 of the blade 31. The slot 5 is through, in other words, the slot 5 comprises an inlet 51 and an outlet 52. The inlet 51 and the outlet 52 extend respectively from the root 32 of the blade 31 to the head 33 of the blade 31. Thus, the slot 5 cuts the blade 31 from the root 32 to the head 33 into a main part 310 comprising the trailing edge 35 and a secondary part 311. The main part 310 is therefore downstream of the secondary part 311 relative to the slot 5.
[0060] The slot 5 comprises a main wall 53 common with the main part 310 and a secondary wall 54 common with the secondary part 311. The main wall 53 and the secondary wall 54 can be included in parallel planes or in curved surfaces, of the same shape or of a different shape.
[0061] The inlet 51 opens onto the extrados wall 37 or onto the intrados wall 38 near the master couple 40 so that part of the air flow arriving at the blade 31 enters the slot 5. In other words, the inlet 51 is made in the blade 31 on a part of the extrados wall 37 or intrados of which a normal vector has an angle of more than 90° with a direction vector of a second direction Y'. The second direction Y' is orthogonal to the master couple 40 and the direction vector is oriented in the direction of flow of the air flow. Advantageously, the inlet 51 is at a distance from the leading edge 34 representing between + / -10% of the curvilinear length of the intrados line 380, in other words of the intrados wall 38, from the leading edge 34 to the trailing edge 35.
[0062] Preferably, at the inlet 51 of the slot 5, the main wall 53 of the slot 5 has in the axial plane PP, i.e. in an axial section 36 of the blade 31, a first direction Y. The first direction Y forms an angle of 45° + / - 25° relative to the second direction Y' orthogonal to the master couple 40.
[0063] The outlet 52 opens onto the extrados wall 37 or onto the intrados wall 38 of the blade 31 downstream of the inlet 51. Preferably, the outlet 52 opens onto the extrados wall 37. Advantageously, the outlet 52 is at a distance from the leading edge 34 of between 20 and 60% of the curvilinear length of the intrados line 380.
[0064] Preferably, at the outlet 52, the main wall 53 is continuous in tangency with the extrados wall 37, in other words with the extrados wall 37 of the main part 310 of the blade 31.
[0065] The slot 5 has a width 55. The width 55 of the slot 5 is constant from the foot 32 to the head 33 but can vary in the slot 5 between the inlet 51 and the outlet 52. The width 55 of the slot 5 is defined by the diameter of circles inscribed in the slot 5, that is to say each of the circles tangent on either side to the main wall 53 and to the secondary wall 54. Preferably, the width 55 at the outlet 52 is less than or equal to the width 55 at the inlet 51. The width 55 of the slot 5 at the outlet 52 is considered at a downstream point of the secondary wall 54 for which the radius of curvature is minimal. The width 55 of the slot 5 at the inlet 51 is considered at an upstream point of the secondary wall 54 for which the radius of curvature is minimal.
Claims
Claims
1. Turbomachine rectifier assembly (21, 25) in which an air flow circulates, the assembly (21, 25) comprising: - an inner shroud (29) extending along a longitudinal axis XX, - an outer shroud (30) radially external to the inner shroud (29), and - a rectifier blade (31) extending radially from the inner shroud (29) to the outer shroud (30), the rectifier blade (31) comprising a leading edge (34) and a trailing edge (35) downstream of the leading edge (34) in the direction of circulation of the air flow, and an extrados wall (37) and a intrados wall (38) extending respectively from the leading edge (34) to the trailing edge (35); the rectifier blade (31) further comprising a through slot (5) formed at least partially in the extrados wall (37) and extending over the entire height of the rectifier blade (31).
2. An assembly according to claim 1, wherein the slot (5) comprises an inlet (51) and an outlet (52), the outlet (52) opening onto the extrados wall (37) and being downstream relative to the inlet (51) in the direction of circulation of the air flow.
3. An assembly according to claim 2, wherein the leading edge (34) is formed by an upstream point (340) of each axial section (36) of the rectifier blade (31) for which the radius of curvature is minimal and the trailing edge (35) is formed by a downstream point (350) of each axial section (36) of the rectifier blade (31) for which the radius of curvature is minimal.
4. An assembly according to claim 3, wherein the slot (5) cuts the rectifier vane (31) into a main portion (310), comprising the trailing edge (35), and a secondary portion (311) and wherein the slot (5) comprises a main wall (53) common with the main portion (310) and a secondary wall (54) common to the secondary portion (311).
5. Assembly according to claim 4, in which, at the inlet (51) of the slot (5), the main wall (53) of the slot (5) has, in an axial plane (PP), a first direction (Y) forming an angle of 45° + / - 25° relative to a second direction (Y') orthogonal to a master couple (40) of an axial section (36) of the rectifier blade (31).
6. An assembly according to any one of claims 2 to 5, wherein the inlet (51) is at a distance from the leading edge (34) of + / -10% of a curvilinear length of the intrados wall (38) from the leading edge (34) to the trailing edge (35).
7. Assembly according to any one of claims 2 to 6, in which at the outlet (52), the main wall (53) has a continuity in tangency with the extrados wall (37) of the rectifier blade (31).
8. An assembly according to any one of claims 2 to 7, wherein the outlet (52) is at a distance from the leading edge (34) of between 20 and 60% of a curvilinear distance of the extrados wall (37) from the leading edge (34) to the trailing edge (35).
9. Assembly according to any one of claims 2 to 8, in which the slot (5) has a width (55) equal to the diameters of circles inscribed in the slot (5), each inscribed circle being tangent to the main wall (53) and to the secondary wall (54), the width (55) of the outlet (52) being equal to or less than the width (55) of the inlet (51).
10. An assembly comprising a plurality of rectifier vanes (31) each comprising the slot (5) according to any one of claims 1 to 9.
11. Turbomachine (1) comprising an exhaust casing (25) formed by the assembly according to any one of claims 1 to 10.
12. Aircraft (100) comprising the turbomachine (1) according to claim 11.