VARIABLE PITCH VANE INCLUDING A MEASURING COLUMN

Abstract

Variable-pitch blade (9a) for an aircraft turbomachine, the blade (9a) comprising a blade (10) defined by a stacking axis (E) and a measuring column (19) which is integral with the blade (10), the measuring column (19) comprising a profiled body (20) arranged at a distance downstream of the blade (10), the body (20) extending along an elongation axis (A) which is substantially parallel to the stacking axis (E) of the blade (10), the body (20) carrying at least one measuring instrument (21) configured to measure at least one parameter of an air flow downstream of the blade (10). Figure for abstract: 2

Description

Title of the invention: VARIABLE PITCHING BLADE COMPRISING A MEASURING COLUMN Technical field of the invention

[0001] The present invention relates to a variable-pitch blade comprising a measuring column, as well as a turbomachine comprising such a blade. 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 modes (in particular "propellant" and "reverser") and at different operating speeds, with the aim in particular of validating or not certain technical solutions implemented.

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

[0004] Thus, to measure for example the parameters of the air flow generated by 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] Engine manufacturers also note that a static measuring device inevitably disturbs (by its presence) the flows flowing in the turbomachine. These disturbances are all the more significant when the blades are variable pitch. These disturbances distort the results obtained, without being able to precisely quantify the inaccuracy of the results.

[0006] 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 a moving element of the turbomachine 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.

[0007] The objective of the present invention is therefore to provide a simple, effective solution and economical to respond to the aforementioned problems. Summary of the invention

[0008] The invention thus proposes a variable-pitch blade for an aircraft turbomachine, the blade comprising a blade defined by a stacking axis E and a measuring column which is integral with the blade, the measuring column comprising a profiled body arranged at a distance downstream of the blade, the body extending along an elongation axis A which is substantially parallel to the stacking axis E of the blade, the body carrying at least one measuring instrument configured to measure at least one parameter of an air flow F downstream of the blade.

[0009] Unlike the prior art, the measuring column is here dynamic and moves together with the blade, which has the following advantages: - fixing the measuring column does not require the presence of a fixed element near the area to be studied; - the measuring column adapts to the blade setting, so as to limit the disturbances generated in the flows and to quantify the aerothermal parameters with very high precision, whatever the blade setting; - the aerodynamic and mechanical behavior of the blade is only very slightly disturbed by the presence of the measuring column; - the measuring column can be used to measure the parameters of the boundary layer formed in the immediate vicinity of an element which is integral with it; - the measuring column is compact and arranged in an open space.

[0010] The blade according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another: - the body is fixed to a trailing edge of the blade via at least two legs, the legs being spaced apart from each other; - the measuring instrument comprises at least one cable which passes internally through one of the two legs; - the body comprises at least two portions connected to each other via a flexible element, so as to be able to adapt to the deformations of the blade in operation; - the body comprises at least two sections fitted into one another, and movable in translation and rotation relative to one another along the elongation axis A, so as to be able to adapt to the deformations of the blade in operation; - the two sections are guided in translation and rotation relative to each other via at least one joint; - the measuring column is balanced, the internal part of the measuring column having a greater mass than the external part of the measuring column; - the measuring column comprises a row of measuring instruments along the axis of elongation A, the measuring instruments being carried by the body; - the body extends along the elongation axis A from an internal end of the blade to an external end of the blade.

[0011] The present invention also relates to an aircraft turbomachine comprising an unducted mobile fan and an unducted fixed rectifier, the fan and / or the rectifier comprising at least one blade as described above. Brief description of the figures

[0012] 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:

[0013] [Fig-1] [Fig.l] is a schematic view in longitudinal half-section of a tur machine comprising an unducted fan provided with a blade according to the invention;

[0014] [Fig.2] [Fig.2] is a detail view of the blade illustrated in [Fig.l];

[0015] [Fig.3] [Fig.3] is a detail view of a flexible element of a measuring column according to a first embodiment variant;

[0016] [Fig.4] [Fig.4] is a perspective view of a measuring column along a second variant of implementation;

[0017] [Fig.5] [Fig.5] is a view of a joint illustrated in [Fig.4] with a detail showing the section of the joint;

[0018] [Fig.6] [Fig.6] is a front view of a measuring column according to a third embodiment variant;

[0019] [Fig.7] [Fig.7] is a schematic view in longitudinal half-section of a tur machine comprising an unshrouded rectifier provided with a blade according to the invention;

[0020] [Fig.8] [Fig.8] is a detail view of the blade illustrated in [Fig.7]. Detailed description of the invention

[0021] In Figures 1 and 7, a turbomachine 1 with longitudinal axis X for an aircraft, such as an airplane, is schematically represented. The turbomachine 1 comprises an unducted mobile fan 2 and an unducted fixed rectifier 3. Such a turbomachine 1 is better known by the English acronym USF for “Unducted Single Fan”.

[0022] The term "unducted" associated with the fan 2 means that the blades 9, 9a of the fan 2 are not surrounded at their free end by a shroud. In the same way, the term "unducted" associated with the rectifier 3 means that the blades 17, 17a of the rectifier 3 are not surrounded at their free end by a shroud.

[0023] As illustrated in Figures 1 and 7, the blower 2 is rotatable around the X axis. The fan 2 is driven in rotation by a power turbine 4 associated with a gas generator 5, the power turbine 4 and the gas generator 5 both being arranged downstream of the fan 2.

[0024] The examples illustrated in Figures 1 and 7 are in no way limiting; the turbomachine could, for example, comprise an unducted fan arranged downstream of the power turbine and the gas generator.

[0025] As illustrated in Figures 1 and 7, the fan 2 is rotated by the power turbine 4 via a speed reducer 6. The speed reducer makes it possible to reduce the rotational speed of the fan relative to that of the power turbine, while increasing its torque. The speed reducer 6 is, for example, an epicyclic gear reducer.

[0026] The gas generator 5 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 connected to each other via a transmission shaft. The gas generator 5 is supplied with air by an air inlet 7 which opens between the blower 2 and the rectifier 3.

[0027] When the turbomachine 1 operates in “propulsor” mode, the fan 2 generates a direct air flow F which flows generally from upstream to downstream around the outer fairings of the streamlined body 8 of the turbomachine 1, so as to propel or move the aircraft forward. A minor part of this air flow F is taken by the air inlet 7 to supply the gas generator 5.

[0028] By convention in the present application, the terms “upstream” and “downstream” are defined relative to the direction of circulation of the direct air flow F, the turbomachine 1 then being in “propulsor” mode.

[0029] The turbomachine 1 is here also configured to operate in “reverser” mode, the fan 2 then generates a reverse air flow which flows generally from downstream to upstream around the external fairings of the body 8 of the turbomachine 1, so as to brake the aircraft at the time of its landing.

[0030] As illustrated in Figures 1 and 7, the fan 2 comprises an annular row of blades 9, 9a with variable pitch, each blade 9, 9a being pitched around an axis of rotation which is substantially perpendicular to the axis X.

[0031] Each blade 9, 9a of the fan 2 comprises a blade 10 defined by a stacking axis E and a root mounted in a cell of a pivot of the fan 2. Each blade 10 extends along the stacking axis E from an inner end 11 (adjacent to the root) to an outer end 12 (commonly called the “top”). Each blade 10 comprises a pressure face 13 and an extrados face connected to each other by a leading edge 14 and a trailing edge 15.

[0032] The fan 2 comprises a control system 16 for the timing of the blades 9, 9a. better known by the English acronym PCM for “Pitch Change Mechanism”. The control system 16 can be common to all the blades 9, 9a or specific to each of the blades 9, 9a.

[0033] As illustrated in Figures 1 and 7, the rectifier 3 is fixed in rotation about the axis X. The rectifier 3 is configured to straighten at least part of the air flow F generated by the blower 2. The rectifier 3 is arranged here directly downstream of the blower 2.

[0034] The rectifier 3 comprises an annular row of vanes 17, 17a (known by the English acronym “OGV” for “Outlet Guide Vane”) with variable pitch, each vane 17, 17a being pitched around an axis of rotation which is substantially perpendicular to the axis X.

[0035] Each blade 17, 17a of the rectifier 3 comprises a blade 10 defined by a stacking axis E and a root mounted in a cell of a pivot of the rectifier 3. Each blade 10 extends along the stacking axis E from an inner end 11 (adjacent to the root) to an outer end 12 (commonly called the “top”). Each blade 10 comprises a pressure face 13 and an extrados face connected to each other by a leading edge 14 and a trailing edge 15.

[0036] The rectifier 3 comprises a control system 18 for the timing of the blades 17, 17a, this control system 18 being able to be common to all the blades 17, 17a or specific to each of the blades 17, 17a.

[0037] A blade 9a, 17a according to the invention (hereinafter referred to as measuring blade 9a, 17a) comprises a measuring column 19 which is integral with the blade 10. The measuring column 19 comprises a profiled body 20 arranged at a distance downstream of the blade 10. The body 20 extends along an elongation axis A which is substantially parallel to the stacking axis E of the blade 10. The body 20 carries at least one measuring instrument 21 configured to measure at least one parameter of an air flow F downstream of the blade 10.

[0038] The blower 2 can of course comprise several measuring vanes 9a. In the same way, the rectifier 3 can of course comprise several measuring vanes 17a.

[0039] The fan 2 may comprise conventional blades 9 (blade not comprising a measuring column 19) and measuring blades 9a. In the same way, the rectifier 3 may comprise conventional blades 17 (blade not comprising a measuring column 19) and measuring blades 17a.

[0040] The blower 2 may comprise only measuring vanes 9a. In the same way, the rectifier 3 may comprise only measuring vanes 17a.

[0041] Advantageously, when the fan 2 comprises several measuring blades 9a, the measuring blades 9a are distributed regularly around the axis X, so as to have a balanced fan, and in other words to avoid imbalances.

[0042] Advantageously, when the rectifier 3 comprises several measuring vanes 17a, the measuring vanes 17a are distributed regularly around the axis X, so as to have a balanced rectifier, and in other words to avoid imbalances.

[0043] A turbomachine 1 can obviously comprise a fan 2 with one or more measuring blades 9a and a rectifier 3 with one or more measuring blades 17a.

[0044] The elongation axis A of the body 20 may have a geometry (or a profile) similar to the trailing edge 15 of the blade 10, in order to have an equal (or constant) distance between the different nozzles 29 of the measuring instruments 21 and the blade 10.

[0045] The body 20 of the measuring column 19 can be fixed to the trailing edge 15 of the blade 10 via at least two lugs 22, the lugs 22 being spaced apart from each other. Advantageously, in this configuration, the cable(s) of the measuring instrument 21 (or measuring instruments 21) pass internally through at least one of the two lugs 22.

[0046] To pass the cables, the blade 10 may be hollow. The measuring blade 9a, 17a may comprise different channels integrated at the time of its manufacture. The cables may be directly integrated into the blade 9a, 17a at the time of its manufacture. For example, for a blade 9a, 17a made of composite material, the cables may be integrated into the fiber preform before the resin injection.

[0047] The body 20 of the measuring column 19 may comprise at least two portions 23 connected to each other via a flexible element 24, so as to be able to adapt to the deformations of the blade 10 in operation. This configuration is particularly suitable for the blades 9a of the fan 2 whose blade 10 deforms significantly (untwisting, twisting, extension, etc.) in operation.

[0048] The flexible element(s) 24 make it possible not to impact the aeromechanical behavior of the blade 10. The behavior of a measuring blade 9a, 17a is thus similar to that of a non-instrumented or conventional blade 9, 17. Consequently, the flexible element(s) 24 make it possible to maintain dynamic homogeneity of the blade crown.

[0049] Advantageously, the flexible element 24 or the flexible elements 24 are located close to the area of the blade 10 which deforms the most during operation.

[0050] A flexible element 24 may be in the form of a bellows, and thus comprise several beads 25 connected to each other.

[0051] The body 20 of a measuring column 19 may comprise at least two sections 26a-26b, 27a-27c fitted into one another, and movable in translation and rotation relative to one another along the elongation axis A, so as to be able to adapt to the deformations of the blade 10 in operation. This configuration is particularly suitable for the blades 9a of the fan 2 whose blade 10 deforms if significantly (untwisting, twisting, extension, etc.) in operation.

[0052] This or these interlockings make it possible not to impact the aeromechanical behavior of the blade 10. The behavior of a measuring blade 9a, 17a is thus similar to that of a non-instrumented or conventional blade 9, 17. Consequently, this or these interlockings make it possible to maintain dynamic homogeneity of the blade crown.

[0053] Advantageously, the nesting or nestings are located close to the area of the blade 10 which deforms the most during operation.

[0054] Two sections 26a-26b, 27a-27c can be guided in translation and in rotation relative to each other via at least one joint 28. The joint 28 can have a lobed profile in section.

[0055] Advantageously, the measuring column 19 is balanced, the internal part of the measuring column 19 having a mass greater than the external part of the measuring column 19. The balancing makes it possible in particular to avoid imbalances. The balancing advantageously places the center of gravity of the measuring column 19, so as not to adversely impact that of the measuring blade 9a, 17a.

[0056] The measuring column 19 may comprise several measuring instruments 21 carried by the body 20, each measuring instrument 21 being configured to measure at least one parameter of the air flow F downstream of the blade 10.

[0057] The measuring instruments 21 can be arranged in the form of a row along the elongation axis A.

[0058] Each measuring instrument 21 can of course be configured to measure several parameters of the air flow F downstream of the blade 10.

[0059] The measuring instrument(s) 21 are for example pressure sensors (or pressure probes) and / or temperature sensors (or temperature probes).

[0060] A measuring instrument 21 may comprise a nozzle 29 projecting from an inlet edge 30 of the body 20. Advantageously, each nozzle 29 is oriented according to the aerodynamic profile of the body 20, so as to minimize disturbances and optimize measurements.

[0061] Advantageously, the body 20 of the measuring column 19 can be made of a flexible material (for example an elastomer), so as to deform easily when the associated blade 10 deforms (untwisting, twisting, extension, etc.) during operation.

[0062] As illustrated in Figures 1 and 2, the fan 2 comprises one or more measuring blades 9a.

[0063] More precisely, the body 20 of the measuring column 19 extends along the elongation axis A from the internal end 11 of the blade 10 to the top 12 of the blade 10. The body 20 is fixed to the trailing edge 15 of the blade 10 via two tabs 22 distant from each other, one of them being located near the inner end 11 of the blade 10 and the other being located near the top 12 of the blade 10. The cables of the measuring instruments 21 pass internally through the legs 22. The measuring column 19 comprises a row of measuring instruments 21 along the axis of elongation A, the measuring instruments 21 being carried by the body 20. Each measuring instrument 21 comprises a nozzle 29 projecting from an inlet edge 30 of the body 20. The lowest measuring instrument 21 of the row is arranged near an envelope covering the roots of the different blades, so as to measure the parameters of the boundary layer of the air flow F which is formed in the immediate vicinity of the envelope. The uppermost measuring instrument 21 is arranged opposite the top 12 of the blade 10, so as to measure the parameters of the air flow F at the top 12 of the blade 10.

[0064] According to a first variant embodiment illustrated in [Fig. 3], the body 20 of the measuring column 19 comprises two portions 23 connected to each other via a flexible element 24. The flexible element 24 is here in the form of a bellows which comprises four beads 25 connected to each other.

[0065] According to a second embodiment variant illustrated in [Fig.4], the body 20 of the measuring column 19 comprises three sections 26a-26b, having a central section 26a and two end sections 26b. The sections 26a-26b are fitted into each other. The sections 26a-26b are movable in translation and rotation relative to each other along the elongation axis A, and otherwise the sections 26a-26b slide and pivot relative to each other. The sections 26a-26b have different diameters, namely D1, D2 and D3. The central section 26a is guided in translation and in rotation relative to each of the end sections 26b via a joint 28. As illustrated in [Fig.5], each joint 28 has in section a lobed profile which comprises four lobes 31. The fixing lugs 22 are each arranged at the level of an end section 26b.

[0066] According to a third embodiment variant illustrated in [Fig. 6], the body 20 of the measuring column 19 is telescopic and comprises three sections 27a-27c fitted into one another. The sections 27a-27c are referenced from the inside to the outside as follows: first section 27a, second section 27b and third section 27c. The sections 27a-27c are movable in translation and rotation relative to one another along the elongation axis A, and otherwise the sections 27a-27c slide and pivot relative to one another. The sections 27a-27c have decreasing diameters, from the first section 27a to the third section 27c. The measuring column 19 is balanced here, to avoid imbalances. The fixing lugs 22 are arranged at the level of the first and third sections 27a, 27c.

[0067] As illustrated in Figures 7 and 8, the rectifier 3 comprises one or more vanes of measure 17a.

[0068] More precisely, the body 20 of the measuring column 19 extends along the axis of elongation A from the inner end 11 of the blade 10 to the top 12 of the blade 10. The body 20 is fixed to the trailing edge 15 of the blade 10 via two lugs 22 spaced apart from each other, one of them being located near the inner end 11 of the blade 10 and the other being located near the top 12 of the blade 10. The cables of the measuring instruments 21 pass internally through the lugs 22. The measuring column 19 comprises a row of measuring instruments 21 along the axis of elongation A, the measuring instruments 21 being carried by the body 20 and distributed regularly. Each measuring instrument 21 comprises a nozzle 29 projecting from an inlet edge 30 of the body 20. The uppermost measuring instrument 21 is arranged opposite the top 12 of the blade 10, so as to measure the parameters of the air flow F at the top 12 of the blade 10.

Claims

Claims

1. Variable-pitch blade (9a, 17a) for an aircraft turbomachine (1), the blade (9a, 17a) comprising a blade (10) defined by a stacking axis (E) and a measuring column (19) which is integral with the blade (10), the measuring column (19) comprising a profiled body (20) arranged at a distance downstream of the blade (10), the body (20) extending along an elongation axis (A) which is substantially parallel to the stacking axis (E) of the blade (10), the body (20) carrying at least one measuring instrument (21) configured to measure at least one parameter of an air flow (F) downstream of the blade (10).

2. Blade (9a, 17a) according to claim 1, characterized in that the body (20) is fixed to a trailing edge (15) of the blade (10) via at least two tabs (22), the tabs (22) being spaced from each other.

3. Blade (9a, 17a) according to claim 2, characterized in that the measuring instrument (21) comprises at least one cable which passes internally through one of the two legs (22).

4. Blade (9a, 17a) according to one of the preceding claims, characterized in that the body (20) comprises at least two portions (23) connected to each other via a flexible element (24), so as to be able to adapt to the deformations of the blade (10) in operation.

5. Blade (9a, 17a) according to one of the preceding claims, characterized in that the body (20) comprises at least two sections (26a-26b, 27a-27c) fitted into one another, and movable in translation and in rotation relative to one another along the axis of elongation (A), so as to be able to adapt to the deformations of the blade (10) in operation.

6. Blade (9a, 17a) according to the preceding claim, characterized in that the two sections (26a-26b, 27a-27c) are guided in translation and in rotation relative to each other via at least one joint (28).

7. Blade (9a, 17a) according to one of the preceding claims, characterized in that the measuring column (19) is balanced, the internal part of the measuring column (19) having a mass greater than the external part of the measuring column (19).

8. Blade (9a, 17a) according to one of the preceding claims, characterized in that the measuring column (19) comprises a row of measuring instruments (21) along the axis of elongation (A), the measuring instruments (21) being carried by the body (20).

9. Blade (9a, 17a) according to one of the preceding claims, characterized in that the body (20) extends along the elongation axis (A) from an internal end (11) of the blade (10) to an external end (12) of the blade (10).

10. Aircraft turbomachine (1) comprising an unducted mobile fan (2) and an unducted fixed rectifier (3), the fan (2) and / or the rectifier (3) comprising at least one blade (9a, 17a) according to one of the preceding claims.

Images