Variable-speed blade including a measuring device

Abstract

Variable pitch fan blade (8a) for an unfaired turbomachine fan, the blade (8a) comprising an aerodynamic blade (9) and a base (10), the blade (9) comprising a recess opening simultaneously onto the upper and lower surfaces (14) and a leading edge (15) of the blade (9), the blade (8a) further comprising a measuring device (26) housed in the recess and clipped onto the blade (9), the measuring device (26) comprising a streamlined body (28) whose outer surface (29) is complementary to the outer surface (30) of the blade (9) to ensure aerodynamic continuity, the body (28) carrying at least one measuring instrument (31) configured to measure at least one parameter of an airflow upstream of the blade (9). Figure for the abstract: 2

Description

Title of the invention: VARIABLE-STOP BLADE COMPRISING A MEASURING DEVICE Technical field of the invention

[0001] The present invention relates to a variable pitch blade comprising a measuring device, as well as a turbomachine comprising such a blade. Technical background

[0002] In the context of the development of a turbomachine, engine manufacturers carry out various tests aimed at measuring parameters (pressure, temperature, etc.) specific to each of the flows flowing in the turbomachine during the different operating modes (in particular "propeller" and "reversing") and at different operating regimes, with the aim in particular of validating or not certain technical solutions put in place.

[0003] To measure these flow-specific parameters, it is known to install intrusive measuring devices, more commonly called "combs" because of their shape, in each of the flows studied. A measuring device is typically mounted on a fixed (or static) element of the turbomachine, such as the fan casing or the nacelle.

[0004] Thus, to measure the airflow parameters upstream of a shrouded fan, it is common practice to mount the measuring device on the fixed housing surrounding the fan. However, such a practice cannot be applied to turbomachinery with an unshrouded fan since there is no fixed element near the fan that could be used to support the measuring device.

[0005] By way of example, a turbomachine known by the English acronym "USF" for "Unducted Single Fan" includes such an unducted fan.

[0006] Engine manufacturers also note that a static measuring device mounted opposite a moving element (for example, the fan) generates turbulence that inevitably disturbs the aerodynamic and mechanical behavior of that moving element. This disturbance thus distorts the results obtained, without being able to precisely quantify the inaccuracy of the results.

[0007] Engine manufacturers also note that static measuring devices cannot measure the parameters (pressure, temperature, etc.) of the boundary layer formed in the immediate vicinity of a moving element (for example, the cone) of the fan. Indeed, sufficient clearance must be maintained between a static measuring device and a moving element to avoid any collision, as the parts are subject to deformation when the turbomachine is in operation.

[0008] The objective of the present invention is therefore to provide a simple, effective, and economical solution to the aforementioned problems. Summary of the invention

[0009] The invention thus proposes a variable pitch blade for an unfaired fan of a turbomachine, the blade comprising an aerodynamic blade and a base, the blade comprising a recess opening simultaneously onto intrados and extrados faces and a leading edge of the blade, the blade further comprising a measuring device brought into the recess and clipped onto the blade, the measuring device comprising a profiled body whose outer surface is complementary to the outer surface of the blade to ensure aerodynamic continuity, the body carrying at least one measuring instrument configured to measure at least one parameter of an airflow F upstream of the blade.

[0010] Unlike the prior art, the measuring device here is dynamic and moves in conjunction with the blade, which offers the following advantages: - the aerodynamic and mechanical behavior of the blade (and more generally of the blower) is not disturbed, which improves the accuracy of the results obtained; - the fixing of the measuring device does not require the presence of a fixed element near the blower; - the measuring device can be used to measure the parameters of the boundary layer formed in the immediate vicinity of a moving element (for example the cone) of the blower.

[0011] The measuring device is simply clipped (or clipped) onto the blade, which allows an operator to quickly interchange the measuring device with another that has, for example, different characteristics.

[0012] The blade according to the invention may include one or more of the following features, taken individually or in combination with each other: - the measuring device is clipped onto the blade in a removable manner, so that the measuring device can be quickly interchanged; - the body comprises a core from which extend two clipping wings which are elastically deformable and facing each other, the core having externally a leading edge, each wing comprising a free end which carries an internal claw, the claws being housed in notches which are formed in a receiving edge of the blade, so as to clip the measuring device onto the blade; - each of the claws extends in a straight line, for example along a vertical axis V of the blade; - each of the claws extends in a curved fashion, each claw extending at an angle a of at least 100°, and for example over an angle a of 180°; - each claw is presented in section in the form of a salient angle, and includes a stop plate and a guide plate connected to each other, the stop plate being preferably perpendicular to the mounting direction of the measuring device on the blade; - the measuring device includes a wedge placed in a defined cavity between the two wings, the wedge being located between an inner face of the web and the receiving edge of the blade, the wedge being configured to counter the aerodynamic forces exerted on the body, so that the measuring device does not unclip; - the measuring instrument includes at least one nozzle protruding from the leading edge, the nozzle having an inlet orifice at its free end; - the measuring instrument is connected to a common connector, the common connector being intended to be connected to a complementary connector placed at the level of a pivot which is associated with the blade.

[0013] The present invention also relates to a turbomachine comprising an unshrouded fan, the fan carrying at least one variable pitch blade as described above. Brief description of the figures

[0014] The invention will be better understood and other details, features and advantages of the invention will become more apparent upon reading the following description, given by way of non-limiting example and with reference to the accompanying drawings in which:

[0015] [Fig-1] [Fig.1] is a schematic longitudinal half-section view of a tower bomachine comprising a blade according to the invention;

[0016] [Fig.2] [Fig.2] is a perspective view of the dawn illustrated in [Fig.1];

[0017] [Fig.3] [Fig.3] is a detailed view of the dawn illustrated in Figures 1 and 2;

[0018] [Fig.4] [Fig.4] is a schematic and partial cross-sectional view of the dawn illustrated in figures 1 to 3;

[0019] [Fig. 5] [Fig. 5] is a perspective view of the dawn illustrated in Figures 1 to 4 in which the measuring device is removed;

[0020] [Fig.6] [Fig.6] is a perspective view of the measuring device alone;

[0021] [Fig.7] [Fig.7] is a schematic view of a measuring device according to a first variant of implementation;

[0022] [Fig.8] [Fig.8] is a schematic view of a measuring device according to a second variant of implementation;

[0023] [Fig.9] [Fig.9] is a schematic view of a measuring device according to a third variant of implementation;

[0024] [Fig. 10] the [Fig. 10] is a perspective view of a measuring device according to a fourth embodiment;

[0025] [Fig. 11] [Fig. 11] is a perspective view of a dawn according to a second embodiment. Detailed description of the invention

[0026] Figure 1 schematically represents a turbomachine 1 with longitudinal axis X. The turbomachine 1 comprises an unducted propulsive fan 2 and a fixed unducted stator 3. Such a turbomachine 1 is more commonly known by the English acronym USF for "Unducted Single Fan".

[0027] As illustrated in [Fig. 1], the fan 2 is driven in rotation about the X-axis by a motor 4 located downstream of the fan 2. Such an arrangement of the turbomachine 1 is more commonly known as a "tractor" in French or a "puller" in English. In such an arrangement, the straightener 3 is located longitudinally downstream of the fan 2.

[0028] The example illustrated in [Fig.1] is in no way limiting; the turbomachine 1 could, for example, include an unfaired fan located downstream of the engine, or two unfaired counter-rotating fans located upstream or downstream of the engine.

[0029] The turbomachine 1 is defined along the longitudinal axis X which corresponds to the axis of rotation of the fan 2.

[0030] The engine 4 here comprises a gas generator and at least one power turbine (or low-pressure turbine) intended to drive the fan 2 in rotation. The fan 2 can be driven in rotation by the power turbine via a speed reducer. The gas generator conventionally comprises, from upstream to downstream, at least one compressor, a combustion chamber, and at least one expansion turbine (or high-pressure turbine). The compressor and the expansion turbine are rotationally coupled to each other via a drive shaft. The gas generator is supplied with air by an air inlet 5 which opens between the fan 2 and the rectifier 3.

[0031] When the turbomachine 1 operates in "propulsion" mode, the fan 2 generates a direct airflow F which flows generally from upstream to downstream around the outer fairings of the streamlined body 6 of the turbomachine 1, so as to propel or move the aircraft forward. A minor portion of this airflow F is drawn through the air inlet 5 to supply the gas generator.

[0032] By convention in this application, the terms "upstream" and "downstream" are defined with respect to the direction of circulation of the direct airflow F, the turbomachine 1 then being in "propeller" mode.

[0033] The turbomachine 1 is also configured here to operate in "reversing" mode; the fan 2 then generates a reverse airflow which flows generally from downstream to upstream around the outer fairings of the tur- body 6 bomachine 1, in order to slow the aircraft, particularly at the time of landing.

[0034] As illustrated in [Fig.1], the blower 2 comprises a disk 7 carrying an annular row of variable-pitch blades 8, 8a, each blade 8, 8a being pitched around an axis of rotation Y which is substantially perpendicular to the axis X.

[0035] As illustrated in the figures, each variable pitch blade 8, 8a is defined by a vertical axis V and a transverse axis T which are perpendicular to each other.

[0036] Each variable pitch blade 8, 8a comprises an aerodynamic (or airfoil) blade 9 and a foot 10 intended to be mounted in a recess of a pivot 11 of the fan 2. The blade 9 extends vertically from the foot 10 to a top 12. Each blade 9 comprises an intrados face 13 and an extrados face 14 connected to each other by a leading edge 15 and a trailing edge 16. The leading edge 15 is located upstream of the trailing edge 16. The foot 10 extends transversely and has a bulbous, dovetail shape in cross-section.

[0037] As illustrated in [Fig. 1], the pivot 11 associated with each blade 8, 8a is mounted to move about the Y axis in a housing 17 of the disk 7 via one or more bearings 18. The disk 7 is driven by the power turbine via a power shaft 19 centered on the X axis and a transmission member 20 coupled in rotation to both the power shaft 19 and the disk 7. The blower 2 also includes an inlet cone 21 which is fixed to the disk 7.

[0038] As illustrated in [Fig. 1], the blower 2 includes a control system 22 for the pitch of the blades 8, 8a, better known by the English acronym PCM for "Pitch Change Mechanism". The control system 22 may, for example, include an actuator 23 common to all the blades 8, 8a and a mechanism 24 specific to each of the blades 8, 8a. This mechanism 24 transforms the movement initiated by the actuator 23 into a rotational movement of the corresponding blade 8, 8a. The movement of the actuator 23 allows for the synchronized adjustment of the pitch of all the blades 8, 8a, notably via the various mechanisms 24.

[0039] The fixed rectifier 3 comprises an annular row of guide vanes 25 (or stator vanes), these being able to be variable pitch or not.

[0040] A variable-pitch blade 8a according to the invention (hereinafter referred to as measuring blade 8a) comprises a measuring device 26 housed in a recess 27 (or notch) formed in the blade 9, the recess 27 opening simultaneously onto the upper and lower surfaces 13, 14 and the leading edge 15 of the blade 9. The measuring device 26 is clipped onto the blade 9 and comprises a profiled body 28 whose outer surface 29 is complementary to the outer surface 30 of the blade 9 to ensure aerodynamic continuity. The body 28 of the measuring device 26 carries to the less one measuring instrument 31 configured to measure at least one parameter of the airflow F upstream of the blade 9.

[0041] The blower 2 can obviously include several measuring blades 8a.

[0042] The blower 2 can include conventional blades (blades 8 with variable pitch not including a measuring device 26) and measuring blades 8a.

[0043] The blower 2 may only include measuring blades 8a.

[0044] Advantageously, when the blower 2 includes several measuring vanes, the measuring vanes 8a are distributed regularly around the X axis, so as to have a balanced blower, and in other words avoid imbalances.

[0045] By way of example, when the blower 2 includes two measuring blades 8a and conventional blades, the measuring blades 8a are mounted in opposition with respect to the X axis, for example at 12 o'clock and 6 o'clock by analogy to the dial of a watch or clock.

[0046] A measuring blade 8a can include several measuring devices 26 distributed over its height, each measuring device 26 being associated with a recess 27 formed in the blade 9.

[0047] A measuring device 26 can obviously include several measuring instruments 31 carried by the body 28 of the measuring device 26.

[0048] A measuring device 26 can be located at any height of the blade 9, for example near the foot 10 or near the top 12.

[0049] Each measuring instrument 31 can obviously be configured to measure several parameters of the airflow F upstream of the blade 9.

[0050] The measuring instrument(s) 31 are, for example, pressure sensors (or pressure probes) and / or temperature sensors (or temperature probes).

[0051] A measuring instrument 31 may include a nozzle 32 projecting from a leading edge 33 of the body 28. Advantageously, each nozzle 32 is oriented along the aerodynamic profile of the blade 9 (and more precisely along the tangent to the mean line (or the camber line) at the level of the leading edge in the portion of the blade considered), so as to minimize disturbances and optimize measurements.

[0052] Advantageously, the body 28 of the measuring device 26 is metallic to offer good mechanical strength (and in particular for the wings), and to impact the untwisting of the measuring blade 8a as little as possible.

[0053] Advantageously, the body 28 of the measuring device 26 is produced by additive manufacturing (for example, additive manufacturing by selective powder bed fusion). Additive manufacturing has the advantage of being able to obtain complex shapes.

[0054] According to the embodiment illustrated in figures 1 to 6, the measuring blade 8a comprises a single measuring device 26 located in the vicinity of the foot 10.

[0055] Such a positioning of the measuring device 26 makes it possible to measure the parameters of the airflow boundary layer F which is formed in the immediate vicinity of the inlet cone 21.

[0056] As illustrated in particular in Figures 4 and 6, the body 28 of the measuring device 26 comprises a core 34 from which extend two elastically deformable clip wings 35 (or cheeks) facing each other. The core 34 has an external leading edge 33. Each wing 35 comprises a free end 36 which carries an internal claw 37 (or internal barb). The claws 37 are housed (or fitted) into notches 38 which are formed in a receiving edge 39 of the blade 9, so as to clip the measuring device 26 onto the blade 9.

[0057] The leading edge 33 of the web 34 is complementary to the leading edge 15 of the blade 9, to ensure aerodynamic continuity. Similarly, the outer faces 40 of the wings 35 are complementary to the upper and lower surfaces 13, 14 of the blade 9.

[0058] As illustrated in particular in Figures 4 and 6, each of the claws 37 extends in a straight line along the vertical axis V of the blade 8a. Each claw 37 has a salient angle in cross-section and comprises a stop plate 41 and a guide plate 42 connected to each other. The stop plate 41 is perpendicular to the mounting direction of the measuring device 26 on the blade 9. The guide plate 42 is substantially inclined along the corresponding side wall 43 of the free end 44 of the receiving edge 39, to facilitate the mounting of the measuring device 26.

[0059] The notches 38 of the receiving edge 39 each have a shape that is complementary to the received claw 37. The free end 44 of the receiving edge 39 tapers (or converges) along the axis T from the notches 38, to facilitate the mounting of the measuring device 26.

[0060] The measuring device 26 is clipped in a removable manner. Indeed, to disassemble the measuring device 26, an operator equipped with a specific tool opens (or spreads apart) the wings 35 to release the claws 37, so as to unclip the measuring device 26. The fact that the measuring device 26 is mounted in a removable manner allows an operator to quickly interchange the measuring device with another that has, for example, a different arrangement of the measuring instruments 31.

[0061] Alternatively, each claw could be in cross-section in the form of a lobe or a bulge or a protuberance.

[0062] Alternatively, each claw could be divided into sections spaced apart from each other.

[0063] As illustrated in Figures 3 and 6, the measuring device 26 comprises four ins Measuring instruments 31 are carried by the body 28. The measuring instruments 31 are arranged in a column and spaced vertically from each other at regular vertical intervals. Each measuring instrument 31 includes a nozzle 32 projecting from the leading edge 33, the nozzle 32 having an inlet orifice 45 at its free end. The nozzles 32 are oriented according to the aerodynamic profile of the blade 9, so as to minimize disturbances and optimize measurements. The inlet orifices 45 of the measuring instruments 31 are vertically aligned.

[0064] The measuring device 26 here includes a shim 46 (visible in [Fig. 4]) placed in a cavity 47 defined between the two wings 35. The shim 46 is located between an inner face 48 of the web 34 and the receiving edge 39 of the blade 9. The shim 46 is configured to counteract the aerodynamic forces acting on the body 28, so that the measuring device 26 does not detach. The shim 46 includes a notch 49 for the passage of the cables 50 of the various measuring instruments 31. The cavity 47 opens to the outside via a lower opening 51 located at the base 10 (visible in [Fig. 3]), to allow the passage of the cables 50 of the various measuring instruments 31.

[0065] The measuring instruments 31 are connected to a common (or centralized) connector on the measuring device 26. This common connector is intended to be connected to an additional connector located at a pivot 11 associated with the measuring vane 8a. This type of connection (more commonly known as "plug and play") optimizes the assembly and disassembly time of the measuring device 26.

[0066] According to the first embodiment illustrated in [Fig.7], the measuring device 26 comprises five measuring instruments 31 carried by the body 28. The measuring instruments 31 are arranged in a column and spaced vertically from each other at a regular vertical pitch.

[0067] According to the second embodiment illustrated in [Fig.8], the measuring device 26 comprises five measuring instruments 31 carried by the body 28. The measuring instruments 31 are distributed in two sub-assemblies spaced vertically apart from each other, namely a lower sub-assembly 52 comprising three measuring instruments 31 and an upper sub-assembly 53 comprising two measuring instruments 31.

[0068] According to the third embodiment illustrated in [Fig.9], the measuring device 26 comprises five measuring instruments 31 carried by the body 28. The measuring instruments 31 are distributed in three sub-assemblies spaced vertically apart from each other, namely a lower sub-assembly 54 comprising two measuring instruments 31, a central sub-assembly 55 comprising a single measuring instrument 31, and an upper sub-assembly 56 comprising two measuring instruments 31.

[0069] According to the fourth embodiment illustrated in [Fig. 10], the free end 36 of each wing 35 is curved and extends over an angle α of approximately 180°. Each of the claws 37 thus extends curvedly over an angle α of approximately 180°. This geometry of the claws 37 makes it possible to strengthen the attachment of the measuring device 26 to the blade 9 by limiting, in particular, the play between the claws 37 and the associated notches 38.

[0070] According to the second embodiment illustrated in [Fig. 1 1], the measuring blade 8a comprises a single measuring device 26 located in the vicinity of the apex 12. Such a positioning of the measuring device 26 makes it possible to measure the parameters of the airflow F in the immediate vicinity of the apex 12. The measuring device 26 can obviously have all the characteristics explained above in relation to the first embodiment.

Claims

Demands

1. Variable pitch fan blade (8a) for an unfaired fan (2) of a turbomachine (1), the fan blade (8a) comprising an aerodynamic blade (9) and a foot (10), the blade (9) comprising a recess (27) opening simultaneously onto intrados and extrados faces (13, 14) and a leading edge (15) of the blade (9), the fan blade (8a) further comprising a measuring device (26) carried in the recess (27) and clipped onto the blade (9), the measuring device (26) comprising a streamlined body (28) the outer surface (29) of which is complementary to the outer surface (30) of the blade (9) to ensure aerodynamic continuity, the body (28) carrying at least one measuring instrument (31) configured to measure at least one parameter of an airflow (F) upstream of the blade (9).

2. Blade (8a) according to claim 1, characterized in that the measuring device (26) is clipped onto the blade (9) in a removable manner, so as to be able to quickly interchange the measuring device (26).

3. Blade (8a) according to any one of the preceding claims, characterized in that the body (28) comprises a web (34) from which extend two clipping wings (35) which are elastically deformable and facing each other, the web (34) having externally a leading edge (33), each wing (35) comprising a free end (36) which carries an internal claw (37), the claws (37) being housed in notches (38) which are formed in a receiving edge (39) of the blade (9), so as to clip the measuring device (26) onto the blade (9).

4. Blade (8a) according to claim 3, characterized in that each of the claws (37) extends in a straight line, for example along a vertical axis (V) of the blade (8a).

5. Blade (8a) according to claim 3, characterized in that each of the claws (37) extends in a curved manner, each claw (37) extending over an angle (a) of at least 100°, and for example over an angle (a) of 180°.

6. Blade (8a) according to any one of claims 3 to 5, characterized in that each claw (37) is in section in the form of a salient angle, and comprises a stop plate (41) and guide plate (42) connected to each other, the stop plate (41) preferably being perpendicular to the mounting direction of the measuring device (26) on the blade (9).

7. Blade (8a) according to any one of claims 3 to 6, characterized in that the measuring device (26) includes a wedge (46) placed in a cavity (47) defined between the two wings (35), the wedge (46) being located between an inner face (48) of the web (34) and the receiving edge (39) of the blade (9), the wedge (46) being configured to counter the aerodynamic forces exerted on the body (28), so that the measuring device (26) does not unclip.

8. Blade (8a) according to any one of claims 3 to 7, characterized in that the measuring instrument (31) comprises at least one nozzle (32) projecting from the leading edge (33), the nozzle (32) having an inlet orifice (45) at its free end.

9. Blade (8a) according to any one of the preceding claims, characterized in that the measuring instrument (31) is connected to a common connector, the common connector being intended to be connected to a complementary connector placed at a pivot (11) which is associated with the blade (8a).

10. Turbomachine (1) comprising an unshod fan (2), the fan (2) carrying at least one variable-pitch blade (8a) according to one of the preceding claims.

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