ASSEMBLY FOR A TURBOMACHINE INCLUDING A VARIABLE-PITCHING BLADE AND A MEASURING DEVICE

Abstract

Assembly for a turbomachine (1) comprising: - a variable-pitch fan blade (8) of an unfaired fan (2) including an aerodynamic blade and a base for mounting in a recess of a pivot (12); - a measuring device (25) comprising an aerodynamic body adjacent to and upstream of the blade, the body carrying at least one measuring instrument configured to measure at least one parameter of an airflow (F) upstream of the blade, the measuring device (25) being configured to be integral with the blade (8) and / or the pivot (12), such that the measuring device (25) moves in conjunction with the blade (8), so as not to disturb the aerodynamic and mechanical behavior of the blade (8). Figure for the abstract: 1

Description

Title of the invention: ASSEMBLY FOR A TURBOMACHINE COMPRISING A VARIABLE PITCHING BLADE AND A MEASURING DEVICE Technical field of the invention

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

[0002] As part 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 regimes (takeoff, cruise, thrust reversal, etc.), in particular with the aim of validating or not certain technical solutions implemented.

[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 parameters of the air flow upstream of a ducted fan, it is customary to mount the measuring device on the fixed casing which surrounds the fan. However, such a practice cannot be transposed to turbomachines comprising an unducted fan since there is no fixed element near the fan which could be used to support the measuring device.

[0005] For example, a turbomachine known by the English acronym “USF” for “Unducted Single Fan” comprises such an unducted fan.

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

[0007] Finally, engine manufacturers note that static measuring devices do not allow the parameters (pressure, temperature, etc.) of the boundary layer formed in the immediate vicinity of the fan cone or disk to be measured. Indeed, sufficient clearance must be maintained between a static measuring device and a moving element to avoid any collision, the parts being likely to deform when the turbomachine is in operation.

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

[0009] The invention thus proposes an assembly for a turbomachine comprising: - a variable-pitch blade of an unducted fan comprising an aerodynamic blade and a foot intended to be mounted in a cell of a pivot; - a measuring device comprising an aerodynamic body which is adjacent to the blade and arranged upstream of the blade, the body carrying at least one measuring instrument configured to measure at least one parameter of an air flow upstream of the blade, the measuring device being configured to be integral with the blade and / or the pivot, so that the measuring device moves jointly with the blade, so as not to disturb the aerodynamic and mechanical behavior of the blade.

[0010] Unlike the prior art, the measuring device is here dynamic and moves together with the blade, which has the following advantages: - the aerodynamic and mechanical behavior of the blade (and more generally of the fan) are not disturbed; - 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 the fan cone or disc.

[0011] The measuring device may be secured only to the blade, only to the pivot or to both.

[0012] The assembly according to the invention may comprise one or more of the characteristics, taken in isolation from one another or in combination with one another: - the measuring device and the blade are distinct from each other, the measuring device comprising a foot connected to the body, the foot of the measuring device being intended to be mounted jointly with the foot of the blade in the socket of the pivot; - the measuring device is mounted on an extension of the blade root; - the extension includes a through hole intended for the passage of the measuring instrument; - the body comprises a leading edge and a trailing edge connected to each other by two side walls; - the body is oriented relative to the blade, so as to guide the air flow exiting the trailing edge towards an extrados face of the blade; - the trailing edge of the body coincides with a leading edge of the blade; - the body includes a leading edge from which two facing wings extend from each other, the wings overlapping the intrados and extrados faces of the blade; - the body comprises at least one tube projecting from the leading edge, the tube having an inlet orifice at its free end, the tube forming a housing in which the measuring instrument is received.

[0013] The present invention also relates to a turbomachine comprising an unducted fan which comprises the assembly as described previously, the root of the blade being mounted in a cell of a pivot of the fan, the measuring device being integral with the blade and / or the pivot. Brief description of the figures

[0014] The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[0015] [Fig-1] [Fig.l] is a schematic view in longitudinal half-section of a tur bomachine comprising an assembly according to a first embodiment of the invention, the assembly comprising a variable-pitch blade and a measuring device;

[0016] [Fig.2] [Fig.2] is an exploded schematic view of a detail of [Fig.l];

[0017] [Fig.3] [Fig.3] is a side view of the assembly illustrated in [Fig.l];

[0018] [Fig.4] [Fig.4] is a top view of the assembly illustrated in [Fig.l];

[0019] [Fig.5] [Fig.5] is a first perspective view of the assembly illustrated in the [Fig.l];

[0020] [Fig.6] [Fig.6] is a second perspective view of the assembly illustrated in [Fig.l];

[0021] [Fig.7] [Fig.7] is a first perspective view of an assembly according to a second embodiment of the invention;

[0022] [Fig.8] [Fig.8] is a second perspective view of the assembly illustrated in [Fig.7], an upstream portion of the blade root extension being hidden to illustrate the mounting of the measuring device on the extension. Detailed description of the invention

[0023] In [Fig.l] a turbomachine 1 with longitudinal axis X is schematically represented. The turbomachine 1 comprises an unducted propulsive fan 2 and an unducted fixed rectifier 3. Such a turbomachine 1 is better known by the English acronym USF for “Unducted Single Fan”.

[0024] As illustrated in [Fig.l], the fan 2 is driven in rotation about the axis X by a motor 4 arranged downstream of the fan 2. Such an arrangement of the turbomachine 1 is better known under the designation "tractor" in French or "puller" in English. In such an arrangement, the rectifier 3 is arranged longitudinally downstream of blower 2.

[0025] The example illustrated in [Fig.l] is in no way limiting, the turbomachine could for example comprise an unducted fan arranged downstream of the engine, or even two unducted counter-rotating fans arranged upstream or downstream of the engine.

[0026] The turbomachine 1 is defined along the longitudinal axis X which corresponds to the axis of rotation of the fan 2.

[0027] 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.

[0028] The blower 2 generates a propulsive airflow F which flows upstream to downstream around the outer fairings of the streamlined body 6 of the turbomachine 1, a minor part of this flow F being taken by the air inlet 5 to supply the gas generator.

[0029] By convention in the present application, the terms “upstream” and “downstream” are defined in relation to the direction of circulation of the air flow F.

[0030] Similarly, by convention in the present application, “longitudinal” or “longitudinally” means any direction parallel to the X axis of the turbomachine 1, and “radial” or “radially” means any direction perpendicular to the X axis of the turbomachine 1.

[0031] As illustrated in [Fig.l], the fan 2 comprises a disk 7 carrying an annular row of variable-pitch blades 8, each blade 8 being set around an axis of rotation Y which is specific to it and which is substantially perpendicular to the axis X.

[0032] As illustrated in the figures, each variable-pitch blade 8 comprises an aerodynamic (or profiled) blade 9 and a root 10 intended to be mounted in a cell 11 of a pivot 12 of the fan 2.

[0033] The blade 9 extends along a stacking axis from the root 10 to a tip 13. Each blade 9 comprises a lower surface face 14 and an upper surface face 15 connected to each other by a leading edge 16 and a trailing edge 17. The leading edge 16 is arranged upstream of the trailing edge 17. The leading and trailing edges 16, 17 are each in the form of a rounded shape.

[0034] The foot 10 has a constant section and extends along an elongation axis which is substantially perpendicular to the stacking axis.

[0035] The foot 10 may be presented in section for example in the form of a bulb, of a dovetail or fir tree. The foot 10 is for example obtained by broaching. The socket 11 of the pivot 12 has a shape complementary to that of the foot 10 to allow its assembly.

[0036] As illustrated in [Fig.l], the pivot 12 associated with each blade 8 is mounted to move about the Y axis in a housing 18 of the disc 7 via two rolling bearings. The disc 7 is annular about the X axis, and can be monobloc (or in one piece) or formed of two half-discs joined to each other. The disc 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 with both the power shaft 19 and the disc 7. The fan 2 also comprises an inlet cone 21 which is secured to the disc 7.

[0037] As illustrated in [Fig.l], the fan 2 comprises a control system 22 for the pitch of the blades 8, better known by the English acronym PCM for “Pitch Change Mechanism”. The control system 22 may for example comprise an actuator 23 common to all the blades 8 and a mechanism 24 specific to each of the blades 8, this mechanism 24 making it possible to transform the movement initiated by the actuator 23 into a rotational movement of the corresponding blade 8. The movement of the actuator 23 makes it possible to adjust the pitch of all the blades 8 in a synchronized manner, in particular via the different mechanisms 24.

[0038] According to the invention, a measuring device 25 is associated with at least one of the variable-pitch blades 8 of the fan 2.

[0039] The turbomachine 1 can obviously comprise several measuring devices 25, each measuring device 25 being associated with a variable-pitch blade 8.

[0040] Advantageously, when the blower 2 comprises several measuring devices 25, the measuring devices 25 are distributed regularly around the axis X, so as to have a balanced blower, and in other words to avoid imbalances.

[0041] A measuring device 25 comprises an aerodynamic (or profiled) body 26 which is adjacent to the blade 9 of the associated vane 8 and arranged upstream of this blade 9. The body 26 carries at least one measuring instrument 27 (visible in [Fig. 2]) configured to measure at least one parameter (pressure, temperature, etc.) of the air flow F upstream of the blade 9. The measuring device 25 is configured to be integral with the vane 8 and / or the pivot 12, so that the measuring device 25 moves jointly with the vane 8, in particular so as not to disturb the aerodynamic and mechanical behavior of the vane 8.

[0042] The body 26 of each measuring device 25 can obviously comprise several measuring instruments 27, each measuring instrument 27 being configured to measure one or more parameters of the air flow F upstream of the blade 9. The measuring instrument(s) 27 are for example pressure sensors (pressure) and / or thermocouples (temperature).

[0043] The fact of securing the measuring device 25 to the blade 8 (which is secured to the pivot 12) or directly to the pivot 12, makes it possible to route the measuring instruments 27 or the associated cables in the pivot 12. This avoids having to resort to one or more loops of excess length which could not be fixed in any case and which would become damaged or detached during rotation of the fan.

[0044] According to the first embodiment illustrated in Figures 1 to 6, the measuring device 25 is mounted on an extension 28 of the root 10 of the blade 8. The extension 28 of the root 10 extends in the extension of its main portion 29 located under the blade 9.

[0045] The measuring device 25 comprises a foot (not visible in FIGS. 1 to 6) and a body 26 which extends radially from this foot.

[0046] More precisely, the body is slightly inclined upstream. The body 26 comprises a leading edge 30 and a trailing edge 31 connected to each other by two side walls 32. The leading edge 30 is arranged upstream of the trailing edge 31. The leading and trailing edges 30, 31 are each in the form of a rounded portion. The trailing edge 31 of the body 26 coincides with the leading edge 16 of the blade 9.

[0047] The body 26 is arranged upstream of the blade 9 and is oriented with respect to the blade 9, so as to guide the airflow F exiting the trailing edge 31 towards the extrados face 15 of the blade 9.

[0048] The body 26 comprises one or more interior cavities (not visible in FIGS. 1 to 6) to allow the passage of the measuring instrument(s) 27.

[0049] The body 26 comprises, for example, five tubes 33 projecting from the leading edge 30. The tubes 33 are spaced radially from each other at a regular pitch. Each tube 33 has an inlet orifice 34 at its free end. The tubes 33 have different lengths so that the different inlet orifices 34 are aligned radially. Each tube 33 forms a housing in which one or more measuring instruments 27 can be received, each tube 33 being connected with at least one internal cavity of the body 26. The different tubes 33 are here located in the immediate vicinity of the cone 21 and the disc 7, to measure the parameters of the air flow F at its boundary layer.

[0050] The foot of the measuring device 25 is mounted in a groove made in the extension 28, the groove having a shape which is complementary to that of the foot to allow its mounting. The foot of the measuring device 25 is for example in the form of a dovetail, so as to take up the centrifugal forces to which it is subjected when the turbomachine is in operation.

[0051] The extension 28 comprises a through hole 35 intended for the passage of the measuring instrument(s) 27. The through hole 35 is formed partly in a bulge 36 which projects upstream of the extension 28.

[0052] The measuring device 25 is here fixed to the blade 8 and moves jointly with blade 8, when its timing is changed.

[0053] According to the second embodiment illustrated in figures 7 and 8, the measuring device 25 is also mounted on an extension 28 of the foot 10 of the blade 8.

[0054] The measuring device 25 comprises a foot 37 (visible in [Fig.8]) and a body 26 which extends radially from this foot 37.

[0055] More precisely, the body 26 comprises a leading edge 30 from which two wings 38 extend opposite one another, the wings 38 overlapping intrados and extrados faces 14, 15 of the blade 9.

[0056] The body 26 includes an internal cavity 39 to allow the passage of the measuring instrument(s).

[0057] The body 26 comprises, for example, two tubes 33 projecting from the leading edge 30. Each tube 33 has an inlet orifice 34 at its free end. Each tube 33 forms a housing in which one or more measuring instruments can be received, each tube 33 being connected to the interior cavity 39 of the body 26. The two tubes 33 are here located in the immediate vicinity of the cone 21 and the disc 7, to measure the parameters of the air flow F at the level of its boundary layer.

[0058] The foot 37 of the measuring device 25 is mounted in a groove 40 made in the extension 28, the groove 40 having a shape which is complementary to that of the foot 37 to allow its mounting. The foot 37 of the measuring device 25 is here in the form of a dovetail, so as to take up the centrifugal forces to which it is subjected when the turbomachine is in operation.

[0059] The extension 28 comprises a through hole 35 intended for the passage of the measuring instrument(s). The through hole 35 is formed partly in a bulge 36 which projects upstream of the extension 28.

[0060] The measuring device 25 is here fixed to the blade 8 and moves jointly with the blade 8 when its positioning is changed.

[0061] According to an embodiment not shown, the measuring device 25 and the associated blade 8 are distinct from one another. The measuring device 25 comprises a foot connected directly or indirectly to the body, this foot of the measuring device 25 being mounted jointly with the foot 10 of the associated blade 8 in the cell 11 of the corresponding pivot 12. The measuring device 25 is here secured to the pivot 12 and moves jointly with the blade 8 (the blade 8 is also secured to the pivot 12), when its setting is modified.

[0062] Advantageously, the foot of the measuring device 25 and the foot 10 of the blade 8 have identical dimensional and geometric characteristics.

[0063] The body of such a measuring device 25 may have the characteristics of the body 26 of the measuring device 25 according to the first embodiment and / or the characteristics of the body 26 of the measuring device 25 according to the second embodiment.

Claims

Claims

1. Assembly for a turbomachine (1) comprising: - a variable-pitch blade (8) of an unducted fan (2) comprising an aerodynamic blade (9) and a root (10) intended to be mounted in a cell (11) of a pivot (12); - a measuring device (25) comprising an aerodynamic body (26) which is adjacent to the blade (9) and arranged upstream of the blade (9), the body (26) carrying at least one measuring instrument (27) configured to measure at least one parameter of an air flow (F) upstream of the blade (9), the measuring device (25) being configured to be integral with the blade (8) and / or the pivot (12), so that the measuring device (25) moves jointly with the blade (8), so as not to disturb the aerodynamic and mechanical behavior of the blade (8).

2. Assembly according to claim 1, characterized in that the measuring device (25) and the blade (8) are distinct from each other, the measuring device (25) comprising a foot connected to the body, the foot of the measuring device (25) being intended to be mounted jointly with the foot (10) of the blade (8) in the socket (11) of the pivot (12).

3. Assembly according to claim 1, characterized in that the measuring device (25) is mounted on an extension (28) of the root (10) of the blade (8).

4. Assembly according to the preceding claim, characterized in that the extension (28) comprises a through hole (35) intended for the passage of the measuring instrument (27).

5. Assembly according to one of the preceding claims, characterized in that the body (26) comprises a leading edge (30) and a trailing edge (31) connected to each other by two side walls (32).

6. Assembly according to the preceding claim, characterized in that the body (26) is oriented relative to the blade (9), so as to guide the air flow (F) leaving the trailing edge (31) towards an extrados face (15) of the blade (9).

7. Assembly according to one of claims 5 or 6, characterized in that the trailing edge (31) of the body (26) coincides with a leading edge (16) of the blade (9).

8. Assembly according to one of claims 1 to 4, characterized in that the body (26) comprises a leading edge (30) from which two wings (38) extend opposite each other, the wings (38) overlapping intrados and extrados faces (14, 15) of the blade (9).

9. Assembly according to one of claims 5 to 8, characterized in that the body (26) comprises at least one tube (33) projecting from the leading edge (30), the tube (33) having an inlet orifice (34) at its free end, the tube (33) forming a housing in which the measuring instrument (27) is received.

10. Turbomachine (1) comprising an unducted fan (2) which comprises the assembly according to one of the preceding claims, the root (10) of the blade (8) being mounted in a cell (11) of a pivot (12) of the fan (2), the measuring device (25) being integral with the blade (8) and / or the pivot (12).

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