MEASURING DEVICE FOR CHARACTERIZING AN AIRCRAFT ENGINE BLADE

Abstract

A measuring device for characterizing a blade (6) of an aircraft engine, comprising at least one measuring chain which includes: - a light wave emission module (1), comprising a laser emitter capable of emitting a light wave towards a targeted area of ​​the blade and at a predetermined distance from the blade, - a light wave reception module (2), capable of receiving a light wave reflected by the blade and producing an electrical signal, - a processing module (4) capable of processing the electrical signal produced by the light wave reception module and deducing data on the physical quantities of the blade, - a data analysis module (5), capable of analyzing the data on the physical quantities of the blade. Figure for the abstract: Figure 1

Description

Title of the invention: MEASURING DEVICE FOR CHARACTERIZING AN AIRCRAFT ENGINE BLADE technical field

[0001] The present invention relates to the monitoring of aircraft engine blades, in particular unfaired blades. More particularly, it relates to a measuring device for characterizing an aircraft engine blade by optical means. PRIOR ART

[0002] There is a need to characterize a blade at different pitch positions to understand and optimize the performance of the aircraft engine module.

[0003] Instrumentation solutions are known for engines with shrouded blades. These solutions implement measuring instruments mounted on the shroud. Therefore, these solutions are not applicable to engines with unshrouded blades.

[0004] To characterize an unshod blade, strain gauge measurement can be considered. This technique only partially meets the requirements due to the number of measurement points needed. It requires a lengthy and expensive design process followed by the risky use of remote sensing.

[0005] It is also possible to consider the Bragg network, but this solution is potentially intrusive and is not yet developed for use on rotating parts.

[0006] It is still possible to consider photogrammetry or videogrammetry, but this solution is strongly constrained by external environmental conditions and by the positioning of camera and lighting devices.

[0007] EP 3 013 685 discloses a method for integrated optical measurement under the wing and within the blade. However, this technique is limited to the vibrational characterization of blades. Furthermore, it is not a non-intrusive technique, since it requires the integration of an optical fiber within the blade, which can impact its vibrational response. In addition, the transmission of the measurement signal by the probe can be degraded by blade vibration. Description of the invention

[0008] The invention aims to solve the problems of the prior art by providing a measuring device for characterizing an aircraft engine blade, comprising at least one measuring chain which includes:

[0009] - a light wave emission module, comprising a laser emitter capable of to emit a light wave towards a targeted area of ​​dawn and at a predetermined distance from dawn,

[0010] - a light wave receiving module, capable of receiving a light wave reflected by the dawn and producing an electrical signal,

[0011] - a processing module capable of processing the electrical signal produced by the module of light wave reception and deduce data on the physical quantities of dawn,

[0012] - a data analysis module, capable of analyzing data of quantities Physics of dawn.

[0013] Thanks to the invention, it is possible to carry out a non-intrusive measurement allowing to measure distances, the presence of the blade in front of the receiver, speeds, deformations, displacements, deflections and pitch / untwist angles of an aircraft blade, without contact and under test conditions.

[0014] The invention applies particularly to unfaired blades, but also to faired blades, for example blades visible from outside the fairing.

[0015] The data obtained allows the study, monitoring or certification of the blades concerned.

[0016] According to a preferred feature, the light wave emission module is capable of emitting light pulses.

[0017] According to an alternative preferred feature, the light wave emission module is capable of emitting a frequency-modulated light wave.

[0018] According to a preferred feature, at least one measurement chain includes an optical probe capable of carrying the light waves emitted from the emitter to the targeted area of ​​dawn and the light waves reflected by the dawn to the receiver.

[0019] According to a preferred feature, the measuring device comprises several measuring chains capable of emitting a light wave towards a respective targeted area of ​​dawn.

[0020] According to a preferred feature, the several measuring chains are capable of each emitting a light wave in the direction of a respective targeted area of ​​the dawn, the targeted area being positioned at a respective height of the dawn, and / or at a respective angular position around the dawn, and / or in a respective plane.

[0021] According to a preferred feature, the measuring device comprises at least one measuring chain capable of emitting a light wave in the direction of the top of the dawn, and of determining at least one property among a time-passage deflection of the top of the dawn and a longitudinal deformation of the dawn.

[0022] According to a preferred feature, the measuring device comprises at least one measuring chain capable of emitting a light wave towards the edge of the blade, and of determining at least one property among: a deflection by measuring the time it takes for the edge of the blade to pass, a calibration / untwisting by measuring the angle of rotation of the blade along its axis relative to the motor and at a given blade height and an axial displacement of the blade.

[0023] The invention also relates to an aircraft comprising a measuring device as previously described.

[0024] The invention also relates to a measurement method for characterizing an aircraft engine blade, using the measuring device as previously described, the method comprising:

[0025] - the control of the light wave emission module, so that the Laser emitter emits a light wave towards a targeted area of ​​dawn and at a predetermined distance from dawn,

[0026] - the control of the light wave receiving module, so that it receives a light waves reflected by the dawn produce an electrical signal.

[0027] - the control of the processing module to process the electrical signal produced by the light wave reception module and deduce data on the physical quantities of dawn,

[0028] - the command for the data analysis module, to analyze the data of physical quantities of dawn.

[0029] The aircraft and the method have similar advantages to those of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages will become apparent from the following description of a preferred embodiment given by way of non-limiting example, described with reference to the figures in which:

[0031] [Fig-1] illustrates a measuring device for characterizing a motor blade aircraft, according to an embodiment of the invention.

[0032] [Fig.2] illustrates a measurement method for characterizing a blade of an aircraft engine, according to an embodiment of the invention.

[0033] [Fig.3] illustrates signals emitted and received during the use of the device in [Fig.1].

[0034] [Fig.4] illustrates an example of implementation of the device according to the invention.

[0035] [Fig.5] illustrates an example of implementation of the device according to the invention.

[0036] [Fig.6] illustrates an example of implementation of the device according to the invention.

[0037] [Fig.7] illustrates an example of implementation of the device according to the invention.

[0038] [Fig.8] illustrates an example of implementation of the device according to the invention.

[0039] Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0040] The different parts represented in the figures are not necessarily shown on a uniform scale, in order to make the figures more legible.

[0041] The different possibilities (variants and embodiments) should be understood as not being mutually exclusive and can be combined with each other.

[0042] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0043] The present invention applies to a blade of an aircraft engine. The engine conventionally comprises a stator and at least one rotor, preferably incorporating a propeller or a turbine rotating about an axis relative to the stator. The propeller comprises several blades.

[0044] The blades here are not shrouded. These are, for example, propeller blades of the open-rotor type. However, the invention applies to shrouded blades provided they are visible from the outside. The application of the invention is advantageous when the blades to be characterized are optically accessible.

[0045] According to a preferred embodiment shown in [Fig. 1], a measuring device for characterizing an aircraft engine blade is preferably integrated into the aircraft. The device comprises a light wave emission module 1, capable of emitting a light wave towards a targeted area of ​​a blade to be characterized 6. By light wave, we mean any signal whose spectrum is close to that of visible light (the visible, infrared, or ultraviolet spectrum). Thus, the device is based on LIDAR (Light Detection and Ranging). In the following, we consider a blade to be characterized, but the invention applies to each of the blades that successively pass in front of the measuring device during their rotation.

[0046] The light wave emission module 1 comprises a laser emitter and an associated electronic control circuit. The emitter emits light pulses.

[0047] As detailed below, the light pulses are directed towards the dawn to be characterized 6.

[0048] The measuring device also includes a light wave reception module 2, capable of receiving a light wave reflected by the louver 6 and producing an electrical signal in response to the received light wave. The light wave reception module 2 includes a light wave receiver and an associated processing circuit that transforms the received light waves into electrical signals.

[0049] The light wave emitter and receiver are preferably connected to an optical probe 3, which carries both the light waves emitted from the emitter towards the dawn and the light waves reflected by the dawn towards the receiver. The light waves are symbolized by arrows. It is also possible to have two physically separate probes for the emission and reception of the light waves.

[0050] The light wave emitter and receiver are also connected to a processing module 4 capable of processing the electrical signal produced by the light wave receiving module 2 and deducing data on physical quantities of dawn.

[0051] The electrical signal produced by the light wave receiving module 2 is a continuous signal, the amplitude of which is constant when the light wave is between two blades and varies, for example in the form of a peak, each time the light wave encounters a blade. The processing module 4 deduces physical quantities of the blade from measurements performed on the electrical signal produced by the light wave receiving module 2.

[0052] The processing module 4 is linked to a data analysis module 5, capable of analyzing the physical quantity data of the dawn in order to characterize the dawn according to different properties.

[0053] The time between two successive signal variations, for example between two successive peaks, is used to determine a deflection.

[0054] The signal amplitude at the level of a signal peak is used to determine an axial displacement and a blade elongation.

[0055] The width of a signal peak is used to determine a blade pitch / untwist.

[0056] It is possible to duplicate the measurement chain described above to target several areas of the dawn in order to characterize the dawn according to different properties, depending on the targeted areas of the dawn. In particular, it is possible to target areas distributed over different heights of the dawn, but also in several angular positions around the dawn and in different planes.

[0057] The operation of the measuring device for characterizing an aircraft engine blade is illustrated by the measurement method for characterizing an aircraft engine blade in [Fig. 2]. The method comprises steps E1 to E4.

[0058] Step El is the command of the light wave emission module, so that the Laser emitter emits a light wave towards a targeted area of ​​dawn and at a predetermined distance from dawn.

[0059] The emitter of the light wave emission module 1 is controlled to emit a light wave, in the form of light pulses. In [Fig. 3], the emitted pulses are represented schematically by a square wave signal U(t), where t represents time.

[0060] By way of example, the transmitter comprises a pulsed laser source that delivers a light signal with a wavelength between 800 and 1000 nm, for example 905 nm, with a pulse duration of 100 ns. The electrical power is 100 W. The receiver has a peak spectral sensitivity between 900 and 1000 nm, for example 900 nm.

[0061] The next step E2 is the command of the light wave receiving module, so that it receives a light wave reflected by the dawn and produces an electrical signal.

[0062] The receiver of the light wave receiving module 2 receives light pulses V(t) reflected by the dawn. They are also schematically represented by a square wave signal in [Fig.2].

[0063] The next step E3 is the command of the processing module to process the electrical signal produced by the light wave receiving module and to deduce data on physical quantities of dawn.

[0064] The received signal is delayed relative to the emitted signal by a duration At which is the travel time for the emitted and received signals to travel the distance between probe 3 and dawn 6. Since the speed of light waves is constant, the travel time At allows the distance between probe 3 and dawn 6 to be calculated.

[0065] When a signal reflected by the blade 6 is received by the optical probe, the frequency of the reflected signal is measured. By referring to the instant when the same frequency value was emitted, the time between the emission and reception of this frequency is measured and allows the distance between the optical probe 3 and the blade 6 to be calculated.

[0066] Alternatively, the laser source is sustained and frequency modulated. This is an FMCW lidar (Frequency Modulated Continuous Wave). The emitted signal is not in the form of light pulses, but is a frequency-modulated light wave.

[0067] The next step E4 is the command of the data analysis module, to analyze the physical quantity data of the dawn in order to characterize the dawn according to different properties.

[0068] It is assumed that the optical probe 3 is positioned at a known distance from the blade 6 to be characterized. Examples of such arrangements are described below.

[0069] For light waves emitted towards the dawn peak:

[0070] - it is possible to determine a deflection by measuring the transit time of the tip timing (in English: tip timing);

[0071] - it is possible to determine a longitudinal deformation (elongation) of the blade by measuring the signal amplitude at a signal peak;

[0072] For light waves emitted towards the edge of dawn:

[0073] - it is possible to determine a deflection by measuring the transit time of leading and trailing edges of the dawn (in English: edge timing);

[0074] - it is possible to determine a timing / untwisting by measuring the angle of rotation of the blade along its axis relative to the motor and at a given blade height;

[0075] - it is possible to determine an axial displacement of the blade by measuring the amplitude of the signal at the level of a signal peak.

[0076] Figures 4 to 8 show examples of implementation of the device according to the invention. In each of Figures 4 to 8, among the elements described above, the only elements shown are the light wave emission module 1, the The light wave receiving module 2, the optical probe 3, and the vane 6 are shown. The paths of the light waves are indicated by arrows. The examples in Figures 3 to 7 each include several optical probes. In practice, each optical probe 3 is associated with a light wave emission module 1 and a light wave receiving module 2. However, only one emission module and one receiving module are shown in Figures 3 to 7 for simplicity.

[0077] The implementation of [Fig.4] relates to unfaired blades of an engine architecture with an unfaired fan (in English: open fan) and can be used both during ground tests and in flight.

[0078] Two types of measurements are possible. The emitted and reflected waves are transported by an optical probe to and from the tip of the dawn 6. The emitted and reflected waves are also transported by another optical probe to and from the edge of the dawn 6. It is possible to determine the deflection by measuring the time of passage of the tip of the dawn ("tip timing") and the deflection by measuring the time of passage of the edge of the dawn ("edge timing").

[0079] For each wave path between the optical probe and the dawn top or edge, the distance can be between a few centimeters and several meters.

[0080] Fig. 5 represents a similar implementation to that of Fig. 3, but on a turboprop engine of an aircraft.

[0081] The implementation of [Fig.6] relates to fairinged blades visible from the outside, and can be used both during ground tests and in flight.

[0082] As in the previous example, two types of measurements are possible. The emitted and reflected waves are transported by an optical probe to and from the tip of the leaf 6. The emitted and reflected waves are also transported by another optical probe to and from the edge of the leaf 6. It is possible to determine the deflection by measuring the time of passage of the tip of the leaf ("tip timing") and the deflection by measuring the time of passage of the edge of the leaf ("edge timing").

[0083] The implementation of [Fig.7] relates to unshod blades for example of turboprop, open fan engine or open rotor, or shod blades visible from the outside, and can be used both during ground tests and in flight.

[0084] The emitted and reflected waves are transported by an optical probe to and from the edge of the dawn 6. The distance between the optical probe and the edge of the dawn can be between a few centimeters and several meters.

[0085] This implementation makes it possible to measure an axial displacement of the blade 6, based on the measurement of the amplitude of the electrical signal produced by the light wave receiving module 2, at the level of a signal peak.

[0086] The implementation of [Fig. 8] relates to unshod blades, for example, of turboprop engines, open-fan engines, or open rotors, or to shod blades visible from the outside, and can be used both during ground testing and in flight. [Fig. 7] illustrates more specifically an unshod blade of an open-fan engine architecture.

[0087] Two types of measurements are possible. The emitted and reflected waves are transported by optical probes to and from several points on the top of the dawn 6. The emitted and reflected waves are also transported by optical probes to and from several points on the edge of the dawn 6 located at different heights of the dawn.

[0088] These probes are distributed to target different angular positions.

[0089] This implementation makes it possible to determine a deflection by measuring the time of passage of the tip of the blade (tip timing), a deflection by measuring the time of passage of the edge of the blade (edge ​​timing), an axial displacement, a pitch / untwist and an elongation of the blade.

Claims

Demands

1. A measurement device adapted for characterizing a blade (6) of an aircraft engine, comprising at least one measurement chain which includes: - a light wave emission module (1), comprising a Laser emitter capable of emitting a light wave towards the top of the blade and at a predetermined distance from the blade, - a light wave reception module (2), capable of receiving a light wave reflected by the blade and producing an electrical signal, - a processing module (4) capable of processing the electrical signal produced by the light wave reception module and deducing data on physical quantities of the blade, - a data analysis module (5), capable of analyzing the data on physical quantities of the blade and determining at least one property among a time-passage deflection of the top of the blade and a longitudinal deformation of the blade.

2. Measuring device according to claim 1, wherein the light wave emission module (1) is capable of emitting light pulses.

3. Measuring device according to claim 1 or 2, wherein the light wave emission module (1) is capable of emitting a frequency-modulated light wave.

4. A measuring device according to any one of claims 1 to 3, wherein at least one measuring chain comprises an optical probe (3) capable of carrying the light waves emitted from the emitter to the targeted area of ​​the dawn and the light waves reflected by the dawn to the light wave receiving module.

5. A measuring device according to any one of claims 1 to 4, comprising several measuring chains capable of emitting a light wave in the direction of a respective targeted area of ​​dawn.

6. A measuring device according to claim 5, wherein the several measuring chains are each capable of emitting a light wave in the direction of a respective targeted area of ​​dawn, the targeted area being positioned at a respective height of the blade, and / or at a respective angular position around the blade, and / or in a respective plane.

7. A measuring device according to any one of claims 1 to 6, comprising at least one measuring chain capable of emitting a light wave towards the edge of the blade, and of determining at least one property among: a deflection by measuring the time of passage of the edge of the blade, a timing / untwisting by measuring the angle of rotation of the blade about its axis with respect to the motor and at a given blade height and an axial displacement of the blade.

8. Aircraft comprising a measuring device according to any one of claims 1 to 7.

9. A measurement method for characterizing an aircraft engine blade, by means of the measuring device according to any one of claims 1 to 7, the method comprising: - the control (E1) of the light wave emission module, so that the Laser emitter emits a light wave towards the top of the blade and at a predetermined distance from the blade, - the control (E2) of the light wave reception module, so that it receives a light wave reflected by the blade and produces an electrical signal, - the control (E3) of the processing module to process the electrical signal produced by the light wave reception module and deduce data on physical quantities of the blade, - the control (E4) of the data analysis module, to analyze the data on physical quantities of the blade and determine at least one property among a time-passage deflection of the top of the blade and a longitudinal deformation of the blade.

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