Method for monitoring torsion of a rotating shaft on a turbine engine of an aircraft

Abstract

A method of monitoring the torsion of a rotating shaft on an aircraft turbine engine, based on measurements from at least three sensors distributed along the rotating shaft, the at least three sensors dividing the shaft into at least two shaft sections, the method comprising: - for each sensor, a step of measuring a parameter dependent on the rotation of the shaft, - for each pair of achievable sensors, a step of calculating a parameter related to the torsion of the shaft, - a step of comparing the different calculated parameters related to the torsion of the shaft with a reference, - at the end of the comparison step, a step of detecting a damage on a shaft section, and - a step of indicating the positioning of the damage on the shaft from the shaft section for which a damage has been detected.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of monitoring an aircraft engine, and more particularly, to the field of monitoring the torsion of a rotating shaft on an aircraft turbine engine, wherein any damage on this shaft is located. BACKGROUND

[0002] Conventionally, the monitoring of the torsion of a rotating shaft of an aircraft is implemented using one or two sensors. A first sensor is installed near the low-pressure compressor or near the fan of the turbine engine, and a second sensor coupled with the first sensor is installed near the low-pressure turbine.

[0003] However, when the torsion monitoring is implemented from only two sensors, the shaft torsion monitoring is viable, not the location of the drift (that is to say, the identification of which shaft section is drifting with respect to the expected), although the effects of the anomaly are propagated over the entire shaft. The monitoring of the shaft then corresponds to a global monitoring of the torsion behavior of the rotating shaft (in this case, the low-pressure shaft). This monitoring is generally dedicated to tests.

[0004] A method is known for controlling the torque oscillations in a mechanical drive train of a power generation system providing electrical power to an isolated electrical grid, the method comprising the step of monitoring changes in the electrical state of the grid.

[0005] A method and a device are also known for monitoring the run-out of a shaft, in particular a shaft having a plurality of spacers or elements rotating with the shaft, the monitoring being implemented using an instrument for measuring the speed of the shaft via the use of a tone wheel.

[0006] These two methods use a specific instrument of the torsion meter type for measuring the current variations according to the torsion of the shaft, or a specific instrument of the tone wheel type for measuring the current variations according to the torsion of the shaft, which makes it necessary to embed on the turbine engine specific sensors or elements dedicated only to this use. This results in an additional volume and an additional mass on the turbine engine only for this purpose.

[0007] A gas turbine is also known comprising a fan section comprising a fan rotatable with a fan shaft, a turbine engine section comprising a turbine and a turbine engine shaft rotatable with the turbine, a power gear box mechanically coupled to the fan shaft and to the turbine engine shaft such that the fan shaft is rotatable through the gear box, the gear box comprising a gear. The turbine engine further comprises a torque monitoring system comprising a gear box sensor actuatable with the power gear and a shaft sensor actuatable with at least one of the shaft of the turbine engine or the shaft of the fan, by using the gear box sensor and the shaft sensor, a torque in the gas turbine engine is determined, the torque monitoring system determines an angular position of the gear of the gear box with respect to at least one of the shaft of the turbine engine or the shaft of the fan.

[0008] The method uses two sensors of the angular position of the gear, only one of the two sensors, typically a rotary counter sensor, is positioned on the shaft, upstream or downstream of the power gear box, to give the angular position of the shaft. The variation of the difference of position is correlated to the torque and only allows to determine if there is a damage on the shaft, without locating the specific section of the shaft on which the damage is located.

[0009] It is also known a controller for a gas turbine engine configured to measure a first rotational speed of an engine shaft at a first end of the shaft and to measure a second rotational speed of the shaft at a second end. The first end can be coupled to a turbine of the engine and the second end can be coupled to a compressor of the engine. The controller is further configured to determine a twist angle of the shaft from the first rotational speed and the second rotational speed, to determine if the twist angle of the shaft is within a predetermined monitoring range of a health state of the shaft, and to record the twist angle of the shaft. The controller can be configured to generate a maintenance alert in response to determining that the twist angle of the shaft is within the predetermined monitoring range of the health state of the shaft.

[0010] This known method uses two rotational speed sensors of the same shaft positioned at both ends of the shaft. The comparison of the speeds allows to monitor the twist of the shaft, in particular at transient phases such as acceleration or deceleration. However, this method also uses sensors dedicated only to this function.

[0011] It is also known a method for detecting a shaft break event, comprising the steps of storing in a memory a shaft oscillation signature determined from known characteristics of the shaft and associated with a shaft break event, monitoring a rotational speed of the shaft, detecting from the rotational speed an oscillation wave superimposed on the rotational speed, said oscillation wave having a wave modulation frequency and a wave modulation amplitude, comparing the oscillation signature with the oscillation wave, and detecting the shaft break event when the oscillation wave corresponds to the oscillation signature.

[0012] The method uses specific techniques to monitor the oscillating wave.

[0013] It is also known from document EP 2893158 a turbine engine comprising at least one rotating axial shaft in a turbine engine casing, an annular reference portion comprising a long reference tooth and a short reference tooth, a first device for detecting the passage of the two reference teeth and measuring the rotation speed of the shaft, an annular measuring portion comprising a longitudinal measuring tooth, and a second device for detecting the passage of the long reference tooth and the measuring tooth to measure the shaft torque.

[0014] The monitoring method of the present document uses two different rotating reference elements on the shaft to provide two angular references on the same shaft, which adds weight to the turbine engine for this monitoring. SUMMARY

[0015] The aim of the present invention is to provide a method for monitoring the health of a shaft of a turbine engine from at least three sensors whose initial function is not a blade tip timing sensor or monitoring the shaft torsion.

[0016] To this end, the invention proposes a method for monitoring the torsion of a rotating shaft on an aircraft turbine engine, based on measurements from at least three sensors distributed along the rotating shaft, said at least three sensors dividing the shaft into at least two shaft sections, the method comprising:

[0017] - for each sensor, a step of measuring a parameter dependent on the rotation of the shaft,

[0018] - for each pair of achievable sensors, a step of calculating a parameter related to the torsion of the shaft,

[0019] - a step of comparing the different calculated parameters related to the torsion of the shaft with a reference,

[0020] - at the end of the comparison step, a step of detecting a damage on a shaft section, and

[0021] - from the shaft section for which a damage has been detected, a step of indicating the localization of the damage on the shaft.

[0022] The method according to the invention thus allows the use of a set of these sensors whose main function is not to measure the torsion of the shaft. Each sensor can thus have different properties and measure different physical signals (radiation emission, capacitance, magnetic, resistance, field, etc.).

[0023] The method according to the invention thus allows to extend the ability to monitor the health of a shaft of a turbine engine by operating a turbine engine equipped with at least three permanently installed or modular sensors.

[0024] Thus, the method according to the application allows to have the case where N sensors are distributed along the shaft on several axial planes, then the shaft is divided into N-1 discrete sections (the space between two sensors). The combination of two measurements among the N measurements allows to produce a torsion monitoring of the shaft section that connects the sensor of the first measurement with the sensor of the second measurement: that is to say, 3 sections are monitored when there are 3 sensors. Thus, when there are N sensors, the method according to the application offers the possibility to generate 2 combined monitoring actions in N sections.

[0025] The sensors are configured to measure at least one parameter related to the rotation of the shaft, in order to be able to track the angular speed of the shaft. For example, according to their main function, they can have a blade tip timing or revolutions per minute (rpm) measurement function, even if the latter is not the initially intended function.

[0026] Based on the data received by the sensors, two shaft monitoring actions can be jointly performed in the following actions:

[0027] When the turbine drives the compressor through the shaft, the static torsion behavior related to the inertial load of the shaft is monitored. This monitoring can include studying: the drift of the expected static behavior on the sections, the limits of the static torsion allowed, the control of the shaft after bird ingestion or blade losses that cause the generation of a fast over-torque that can cause damage that will reduce the life of the shaft, or the detection of wear of the connecting elements between the different parts of the shaft, such as splines.

[0028] The monitoring of the dynamic behavior (oscillations around the static angular position) can include: the cumulative time spent at the vibration level of each section, the detection of behavior drift, the presence of two or more measurement planes that allows to check that the modes observed at the frequencies are indeed torsion modes. Indeed, at high frequencies, it is not rare to observe several modes at the same frequency. The multiplication of the planes allows to filter the modes that are not torsion modes and to analyze the real amplitude of the torsion modes separately.

[0029] A monitoring of a reduction gear shaft, including: tracking the torsion modes (high frequency modes, engine harmonics multiplied by the number of teeth of the gear) excited by the presence of the gearbox, the detection of gear wear, the detection of back-off modes for which the sensors must be placed on each side of the gearbox.

[0030] These multiple monitoring actions on the multiple sections of the shaft are then converted into a combination of health indicators that allows to estimate the behavior drift and the severity of the health (mechanical health of the shaft) degradation. These indicators are then compared and aggregated with each other to locate the raising of an alert that will then allow to orient the inspection and maintenance operators.

[0031] Thus, the method according to the application allows to distinguish higher order vibration modes with an optimized number of sensors and segments, and to overcome possible presence of nodes with respect to the sensors, and finally to segment the monitoring by taking into account possible presence of reduction gears.

[0032] According to a first aspect of the method for monitoring the torsion of a rotating shaft, at least one of the sensors used to locate the damaged sensor can be a sensor permanently installed on the turbine engine.

[0033] By using sensors already present on the turbine engine and dedicated to functions other than the function of monitoring the torsion of the shaft, the volume and weight necessary for such monitoring are minimized.

[0034] According to a second aspect of the method for monitoring the torsion of a rotating shaft, the method can further comprise a preliminary step of installing at least one removable autonomous modular sensor, at least one of the sensors used to locate the damaged sensor being a modular, autonomous and removable sensor.

[0035] Thus, the use of a removable sensor allows to occasionally add a sensor at a specific location on the turbine engine in order to segment the monitoring of the shaft in a specific way only when any damage on the shaft is isolated and located.

[0036] In another object of the application, an assembly for monitoring the torsion of a rotating shaft on an aircraft turbine engine is proposed, the assembly comprising:

[0037] - at least three sensors for measuring a parameter dependent on the rotation of the shaft, said sensors being distributed along the rotating shaft so as to divide the shaft into at least two shaft segments,

[0038] - a computing device configured to compute a parameter related to the torsion of the shaft for each pair of achievable sensors,

[0039] - a comparison device configured to compare the different computed parameters related to the torsion of the shaft with a reference,

[0040] - a device for detecting a damage on a shaft segment from the information transmitted by the comparison device, and

[0041] - a device for indicating the location of the damage on the shaft, said device being configured to indicate the damaged segment from the indication of the shaft segment for which a damage has been detected by the detection device.

[0042] According to a first aspect of the assembly for monitoring the torsion of a rotating shaft, one of the sensors used to locate the damaged sensor can be a modular, autonomous and removable sensor.

[0043] According to a second aspect of the assembly for monitoring the torsion of a rotating shaft, each sensor is selected from a magnetic sensor, an acoustic sensor, a capacitive sensor and an optical sensor.

[0044] In another object of the application, a turbine engine is proposed, configured to receive an assembly for monitoring the torsion of a rotating shaft as defined above, comprising a casing and an opening of said casing for accessing each sensor contact.

[0045] According to a first aspect of the turbine engine, at least one of the sensors can be a sensor permanently installed on the turbine engine.

[0046] Another object of the application proposes an aircraft comprising at least one turbine engine as defined above. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 A flowchart of a method for monitoring the torsion of a rotating shaft of an aircraft turbine engine according to one embodiment of the application is presented.

[0048] Figure 2 An example of a segment of the monitoring of a rotating shaft according to one embodiment of the application is shown.

[0049] Figure 3 An example of a sensor intended to be temporarily installed on a turbine engine to implement the torsion monitoring and other functions is schematically shown.

[0050] Figure 4 A turbine engine according to one embodiment of the application is schematically shown on a drawing on which a turbine engine 10 according to one embodiment of the application is schematically shown, on which a permanent sensor and a modular and autonomous assembly for detecting Figure 3 the angular position of the blades of a bladed impeller are installed.

[0051] Figure 5 A damage detection assembly for the blades of a bladed impeller of an aircraft turbine engine having a first configuration is schematically shown.

[0052] Figure 6 A damage detection assembly for the blades of a bladed impeller of an aircraft turbine engine having a second configuration is schematically shown.

[0053] Figure 7 A flowchart of a method for detecting the angular position of the blades of a turbine engine impeller is presented.

[0054] Figure 8A flowchart of a method for detecting damage to one or several blades of a wheel constituting an aircraft engine according to an implementation of the application is presented, the method comprising detecting the angular position of the blades of the wheel. DETAILED DESCRIPTION

[0055] The application applies generally in the case of a predictive maintenance service implemented by an aircraft engine manufacturer.

[0056] Figure 1 A flowchart of a method for monitoring the torsion of a rotating shaft of an aircraft turbine engine according to an implementation of the application is shown.

[0057] The monitoring method comprises a first step 100 in which each sensor measures a parameter dependent on the rotation of the shaft.

[0058] In a next step 110, pairs of measurements are constituted, each measurement being associated with a measurement from another sensor, and a parameter related to the torsion of the shaft is calculated for each pair. For N sensors, there will thus be a number equal to N(N-1) / 2 possible to form.

[0059] In a next step 120, the different parameters related to the torsion of the shaft calculated in step 110 are compared with respective reference values.

[0060] In a next step 130, it is detected whether there is damage on the shaft section based on the result of the comparison step 120.

[0061] Finally, if a section is detected as damaged, in a next step 140, the damage on the shaft is located from the shaft section where the damage was detected in step 130.

[0062] Figure 2 An embodiment of the segmentation of the monitoring of the rotating shaft 19 is shown from a first sensor mounted facing the first end of the shaft 19, from a second sensor 73 mounted between the two ends of the shaft 19, and from a third sensor 75 mounted facing the second end of the shaft 19. The three sensors 71, 73 and 75 are coupled to a main casing 80 configured to perform the calculations of the method.

[0063] The three sensors 71, 73, 75 form three sections. A first section A extending between the first sensor 71 and the second sensor 73, a second section B extending between the second sensor 73 and the third sensor 75, and a third section C extending between the first sensor 71 and the third sensor 75. The third section C thus has a length equal to the sum of the first section A and the second section B. The addition of sensors thus allows to pass from a single torque measurement to three torque measurements compared to a configuration with two sensors.

[0064] Advantageously, the comparison of the three measurements with the benchmark allows for the identification of the segment that has drifted the most (static or dynamic) compared to the expected value, and thus allows for directional inspection in this direction. This is the location of the damage (E): the drift is concentrated in the first segment A and no longer concentrated in the large segment C.

[0065] The segment is determined by the number of available sensors, such as the number of available sensors for measuring the angular position of the elements used to actuate the shaft (comparison of the passage time of a specific element). The discretized sensor positioning of the actuating shaft is consistent with the shape and / or Young's modulus variations based on the shaft's design and manufacturing under nominal conditions.

[0066] This method is applicable to different turbine engine architectures, allowing for the monitoring of shaft torsion while minimizing the impact of integration on the turbine engine.

[0067] In one configuration, sensor data from a first set of sensors permanently mounted on the turbine engine for other tasks may be used. In another configuration, in addition to data from the first set of sensors, sensor data from a second set of sensors temporarily mounted to perform torsion monitoring and / or other tasks may also be used.

[0068] Figure 3 An embodiment of a sensor is schematically illustrated, which is intended to be temporarily mounted on a turbine engine to perform torsion monitoring and another function.

[0069] The sensor is in the form of a modular and autonomous component 1 for detecting the angular position of the impeller blades, and the detection component 1 is designed to be mounted on the turbine engine 10. Therefore, component 1 has the primary function of detecting the angular position of the impeller blades and is further used for monitoring the torsion of the turbine engine shaft.

[0070] exist Figure 3 In the illustrated embodiment, the modular and autonomous detection component or kit 1 includes a main housing 711, which can be connected with... Figure 2 The first sensor 71 is the same as the second sensor 72. Alternatively, the component may include more than two sensors.

[0071] Can be with Figure 2 The main housing 80 and the main housing 711 include a communication unit 711a, a main power battery 711b, a storage unit 711c, two reversible manual fastening clips 711d, and a main processing unit 711e.

[0072] Part of the storage unit 711c is a RAM-type random access memory dedicated to computation, and another part of the storage unit 711c is an NVRAM-type read-only memory used to store the results and configuration parameters of the main processing unit 711e (such as a processor).

[0073] The reversible manual fastening clip allows the main housing 711 to be fastened to the turbine engine 10 without tools and in an easily removable manner. The fastening clip 711d is a multi-point physical fastener for mechanical attachment to the turbine engine 10.

[0074] Each sensor 71 and 72 includes a detection module, denoted as 71a and 72a respectively, such as a leaf-end timing sensor of the capacitive, optical, inductive, or pressure type; a local battery, denoted as 71b and 72b respectively; a communication module, denoted as 71c and 72c respectively, which allows communication with the communication unit 711a of the main housing 71; two reversible manual clamps, denoted as 71d and 72d respectively; and a local processing unit, such as a processor, denoted as 71e and 72e respectively.

[0075] Reversible manual clamps 71d or 72d allow for tool-free and easy-to-remove fastening of sensors 71 or 72 to the turbine engine 10. Clamps 71d or 72d are multi-point physical fasteners for mechanical attachment to the turbine engine 10.

[0076] Information picked up by the detection module 71a or 72a of sensor 71 or 72 is transmitted to the local processing unit 71e or 72e, which prepares the signal before the communication module 71c or 72c transmits the signal to the communication unit 711a of the main housing 711. The local processor 71e or 72e is capable of converting the raw information acquired at tens of kHz from the detection module 71a or 72a into a transmittable signal (digitization, compression, preprocessing, blade pass detection).

[0077] exist Figure 3 In the illustrated embodiment, the communication modules 71c or 72c of sensors 71 and 72 are adapted to transmit and receive wireless information, and the communication unit 711a of the main housing 711 is configured and adapted to receive information transmitted via a wireless communication network.

[0078] Alternatively, the detection component 1 may include a single power source, such as a battery, which is located in the main housing 711 and supplies power to the sensors 71 and 72 via a wired connection.

[0079] Figure 4 A turbine engine 10 according to one embodiment of the present invention is schematically shown, on which permanent sensors are mounted and for detection. Figure 3Modular and autonomous assembly of the angular position of the blades of the impeller of a wind turbine.

[0080] In Figure 4 In the embodiment illustrated, the detection kit 1 comprising only the first sensor 71 and the second sensor 72 is installed on the turbine engine 10. The first sensor 71 is installed on the nacelle of the turbine engine 10, facing the fan 11, to allow it to implement monitoring of the health of the blade arrangement of the fan 11. The second sensor 72 is installed on the nacelle of the turbine engine 10, facing the blade arrangement 12 of the stages of the low-pressure compressor. The main casing 711 is installed on the low-temperature zone of the casing of the fan of the turbine engine 10 as such.

[0081] The first sensor 71 and the second sensor 72 are installed in housings 70 on the turbine engine, which are provided for this purpose and equipped with an access opening to the nacelle, which allows easy opening and closing of access to these housings, to install or remove the sensors 71 and 72.

[0082] The main casing 711 can also be housed in a location provided with a dedicated access opening for this purpose. This access opening can also be shared with a casing dedicated to receiving another element of the turbine engine, such as an oil access opening.

[0083] In Figure 4 In the embodiment illustrated in

[0084] In Figure 4 The first and second of the three other locations 70 are positioned at the rear of the turbine engine 10, one facing the stages 13 of the low-pressure turbine engine and the other facing the stages 22 of the high-pressure turbine engine. The third of the three other free locations 70 is positioned on the nacelle of the turbine engine 10, facing the stages 21 of the high-pressure compressor.

[0085] Thanks to these locations 70, in another configuration, it will be possible to have two other sensors positioned to monitor the stages 21 of the high-pressure compressor and the stages 22 of the high-pressure turbine coupled by the transmission shaft 19.

[0086] In a configuration in which the turbine engine will comprise a reduction gear between the fan 11 and the low-pressure compressor 12 and / or a reduction gear between the high-pressure turbine 22 and the low-pressure turbine 13, the turbine engine can also comprise a location 70 for receiving a sensor at the reduction gear.

[0087] Figure 5An assembly 20 is schematically shown for detecting damage to the bladed impeller 11 or the blades of the impeller of an aircraft turbine engine 10 with a first configuration.

[0088] The component 20 for detecting damage includes a method for detecting... Figure 5 The kit 1 shows the position of the impeller blades and the alarm device 9.

[0089] In order to improve Figure 5 For readability reasons, not all components of Kit 1 are shown. Kit 1 actually includes... Figure 3 All the components described herein, namely, the main housing 711, the first sensor 71 and the second sensor 72, the main housing 711 specifically includes a main processing unit 711e and a storage unit 711c in the form of one or more databases D1, D2.

[0090] The first sensor 71 and the second sensor 72 of the component 1 used to detect the position of the blade, in addition to being used to detect the rotation counter, also form the data acquisition device 7 of the damage detection component 20.

[0091] When the blade position detection kit 1 is integrated into the damage detection assembly 20, the main processing unit 711e includes additional means for detecting damage. Therefore, the main processing unit is configured to execute a computer program comprising code instructions designed to perform acquisition, signal processing, analysis, and alarm algorithms according to the damage detection method of the present invention.

[0092] The acquisition device 7 is configured to acquire time signals S1 associated with the blades 111 to 115 of the bladed impeller 11 (e.g., the bladed impeller of the fan of the engine 10 or any other bladed impeller).

[0093] Advantageously, the acquisition device 7 uses blade tip timing technology to measure the passage time / time of arrival (TOA) of blades 111 to 115.

[0094] like Figure 4 As shown, the first sensor 71 (which is a blade timing sensor) of the acquisition device 7 is mounted on the housing of the engine 10 and aligned with the bladed impeller 11 of the fan in order to acquire a time signal S1 specific to the first sensor 71.

[0095] More specifically, the blade tip timing sensor 71 detects and counts the passage of the blade tips of blades 111 to 115 relative to a time base. Therefore, the blade tip timing sensor 71 can measure the current passage time (also known as a "rotation counter") between blades 111 to 115 relative to a reference point. For the blade tip timing sensor 71, the passage time (TOA) specific to each blade 111 to 115 can then be derived from the data measured by the main processing unit 711e, via a calculation module 713 within the main processing unit 711e.

[0096] In other words, the blade tip timing sensor 71 allows for the acquisition of measurements related to the passage time / moment of the blade tip of each blade 111 to 115, which passes over a reference area of ​​the impeller 11 equipped with the blades. Furthermore, when several sensors 71 are used on the same impeller, to limit the risk of loss of the blade tip timing sensors 71, the sensors 71 can be positioned such that their azimuth distance is maximized, keeping them as far apart as possible. Therefore, in the event of a partial failure of a sensor 71 (e.g., impact of debris on the blade 111, contamination of the sensor 71), the risk of affecting all sensors 71 is minimized.

[0097] During normal operation, blades 111 to 115 will pass in front of the same blade tip timing sensor 71 in a regular pattern. Therefore, at a given revolutions per minute (rpm), the time interval Δt between the passing of two successive blades for sensor 71 is measured.

[0098] Conversely, when the blade passes in front of at least one sensor 71, a change in the state of the blade (e.g., due to wear or due to the ingestion of foreign matter (FOD) (foreign matter damage)) will cause a change in the position of the blade.

[0099] In order to identify each blade 111 to 115 independently of their state, the main processing unit 711e is configured to analyze different time signals S1 relative to the angular reference.

[0100] In this implementation, by Figure 5 Kit 1, used for detecting the "rotation counter", provides an angular reference and specifically avoids the use of a tone wheel.

[0101] The "rotation counter" detection component 1 is configured to detect the relative angular position of the blades of a first impeller and the blades of a second impeller 12. The first impeller, such as the impeller 11 of a fan whose blades are monitored for damage using a first sensor 71, is traversed by the same airflow. Figure 5 In the embodiment shown, it is driven by the same shaft 19 of the turbine engine 10.

[0102] The damage of the blades of the second impeller 12 can also be monitored by using other blade end timing sensors, such as the second sensor 72, mounted facing the second impeller 12, in the same way as the first impeller 11.

[0103] The first impeller 11 comprises a first number of blades N1 and the second impeller 12 comprises a second number of blades N2, the first number of blades N1 of the first impeller 11 and the second number of blades N2 of the second impeller 12 being different and not having a common divisor. Thus, the first and second number of blades N1 and N2 are coprime. The blades are evenly distributed on each of the impellers 11 and 12. Thus, on the same impeller 11 or 12, two adjacent blades are separated by the same angular interval.

[0104] The first sensor 71 and the second sensor 72 are time-synchronized on the same clock and are configured to generate a signal at each passage of a blade of the first impeller 11 or of the second impeller 12 in front of the respective sensor 71 or 72.

[0105] The main processing unit 711e of the detection kit 1 is configured to determine the time interval separating the detection of a blade of the first impeller 11 and the detection of each blade of the second impeller 12.

[0106] The first embedded sensor 71 returns a first time signal S1 each time a blade of the first impeller 11 passes in front of it. The second embedded sensor 72 returns a second time signal S2 each time a blade of the second impeller 12 passes in front of it. The time interval between the detections, AT1 for the first impeller 11, AT2 for the second impeller 12, depends on the rotation speed of the shaft 19, on the number of blades of each impeller 11, 12.

[0107] Figure 6 A kit 20 for detecting the damage of the blades of an impeller 11 of an aircraft turbine engine 10 having a second configuration is schematically shown.

[0108] Figure 6 The second configuration of the turbine engine 10 shown in Figure 5 The second configuration of the turbine engine 10 shown in

[0109] Figure 7 A flowchart of a method for detecting the angular position of the blades of an impeller of a turbine engine according to one embodiment of the application is presented. The rotating counter detection kit 1 can implement this method to detect the rotating counter.

[0110] The method comprises a first step 200 in which the first sensor 71 detects the passage of each blade 111 to 115 of the first impeller 11.

[0111] At the same time, in a second step 210, the second sensor 72 detects the passage of each blade 121 to 127 of the second impeller 12.

[0112] The disc measures 2π radians. Moreover, by association with the rotational speed of the shaft, 1 revolution / minute = 2π / 60 rad.s is obtained -1 .

[0113] For a fixed rotational speed (expressed below in revolutions per minute (RPM)), the time interval separating the passage of two successive blades of the same impeller, which has N blades in front of the sensor associated with the impeller, is determined by the following equation:

[0114] [Equation 1]

[0115]

[0116] For the first impeller 11 and its dedicated first sensor 71, it is thus obtained:

[0117] [Equation 2]

[0118]

[0119] And for the second impeller 12 and its dedicated second sensor 72, it is thus obtained:

[0120] [Equation 3]

[0121]

[0122] Thus, in the same shaft rotation, the first and second sensors will not have the same number of detections of blade passages.

[0123] In the embodiment illustrated in Figure 3 and Figure 4 , the first impeller 11 comprises five blades, that is to say N1=5, marked 111 to 115, and the second impeller 12 comprises seven blades, that is to say N2=7, marked 121 to 127. For ease of calculation, the speed of the shaft equal to 60 / 2π revolutions / minute is considered, that is to say revolutions per minute (RPM) = 60 / 2π revolutions per minute (rpm).

[0124] With these characteristics, and for simplicity considering that the sensors have the same angular position, it is obtained at the end of the first step 200 and of the second step 210, the recording of the passage times of the following blades:

[0125] [Table 1]

[0126] First sensor 71 Second sensor 72 0.100 0.050 0.300 0.192 0.500 0.335 0.700 0.478 0.900 0.621 1.100 0.764 1.300 0.907

[0127] It is important to note that the blades do not necessarily need to be initially facing the sensor, which introduces a time constraint before the first detection.

[0128] In the third step 220, the main processing unit 711e calculates the time interval Δt at which the blades of the first impeller 11 pass through each of the blades 121 to 127 of the second impeller 12.

[0129] exist Figure 5 In the first embodiment shown, the two impellers 11 and 12 are driven by the same shaft 19. By comparing the arrival times of blades 111 to 115 of the first impeller 11 with the arrival times of blades 121 to 127 of the second impeller 12, a matrix is ​​obtained:

[0130] [Table 2]

[0131]

[0132]

[0133] The value of the matrix corresponds to the difference between the arrival times of blades 111 to 115 of the first impeller 11 and the arrival times of blades 121 to 127 of the second impeller 12, that is, the time interval represented by ΔT.

[0134] Alternatively, the calculation of the time interval ΔT can take into account the deceleration coefficient of the deceleration device 198 (if it exists).

[0135] For example, in Figure 6 In the second embodiment shown, the two impellers 11 and 12 are not located on the same shaft, but are driven by two different shafts 190 and 195, which are connected by C 减速齿轮 The reduction gear 198 is connected together. Therefore, for the first impeller 11 and its dedicated first sensor 71, the following is obtained:

[0136] [Mathematical Expression 4]

[0137]

[0138] Furthermore, for the second impeller 12 and its dedicated first sensor 72, the following is thus obtained:

[0139] [Mathematical Expression 5]

[0140]

[0141] If a similar comparison is made in the second embodiment, but this time by calculating the difference between the first time, corresponding to the arrival time of the blades 111 to 115 of the first impeller 11, and the second time, corresponding to the arrival time of the blades 121 to 127 of the second impeller 12, the same matrix as that indicated in the table called Table 2 is obtained. 减速齿轮 the product of the coefficient with the arrival time of the blades 111 to 115 of the first impeller 11, the second time corresponding to the arrival time of the blades 121 to 127 of the second impeller 12, the same matrix as that indicated in the table called Table 2 is obtained.

[0142] The matrix table thus provides as many angular references as expected. The blades from one impeller to the other do not have to be aligned as indicated in the matrix table. If the two impellers are aligned so that one blade of each aligned impeller is aligned with the other, we will have a cell in the table for which the difference will be zero.

[0143] This database can then be manipulated by algorithms.

[0144] Alternatively, it is also possible to normalize the calculation of the time interval AT with respect to the rotational speed of the shaft 19 driving the two impellers 11, 12, so that the calculation is independent of the rotational speed.

[0145] Next, in a fourth step 230, the main processing unit 711e determines the relative angular position of each blade 111 to 115 of the first impeller 11 with respect to the angular position of the blades 121 to 127 of the second impeller 12, as a function of the values of the interval AT and the number of revolutions per minute (rpm) of the first and second impellers 11, 12.

[0146] In Figure 1 and Figure 2 In the example shown in the above table and above, the last two blades 115 and 127 to be detected at the end of rotation have the smallest time deviation At. But this result remains random since it is related to the shift offset of the first detection. The offset difference between the two impellers 11 and 12 as such will be related to the mounting of the first and second impellers 11 and 12 on the shaft 19 and to the angular position of the first and second sensors 71 and 72. This offset therefore falls within the production and assembly of the turbine engine 10.

[0147] In the case where the first sensor 71 and the second sensor 72 are aligned with the same angular reference, the offset is only related to the assembly of the impellers 11 and 12 on the shaft 19 and to their relative alignment.

[0148] This offset is a characteristic of the turbine engine 10 and the resulting alignment between the blades from one impeller to the other is inherent to the turbine engine 10. Here, this alignment is presented with respect to the passage time of the blade end timing sensors with respect to the blades, which is ultimately a time feature of this alignment of the blades.

[0149] Finally, in a fifth step 240, the main processing unit 711e designates as the angular reference, that is to say, the rotation counter, the blade of the first impeller 11 having the smallest time deviation At from the blade of the second impeller 12.

[0150] As mentioned above, the fifth blade 115 of the first impeller 11 and the seventh blade 127 of the second impeller 12 are the most aligned blades.

[0151] This property of alignment allows to arbitrarily determine that the fifth blade 115 of the first impeller 11 will be considered as the rotation counter, that is to say, as the angular reference. Based on the analysis of the matrix table described above, another blade of the first impeller 11 can have been arbitrarily designated as the rotation counter.

[0152] The alignment of the blades from one impeller to the other remains the same as it is related to the assembly and to the number of corresponding blades of the impellers. The identification of the rotation counter only requires the identification of one rotation by the deployed algorithm.

[0153] Thus, in each flight of the aircraft comprising the turbine engine 10, the first rotation of the engine 10 allows to reconstitute the rotation counter. Then, each detection of a blade selected as the rotation counter will give a time reference within the meaning of the blade tip timing and an angular reference within the meaning of the rotation counter.

[0154] The blade damage detection system 20 seeks to detect a lasting degradation of the performance of one or several blades 111 to 115 related to a damage, and not a simple temporary disturbance observable on the signal S1. Thus, the angular reference described above (rotation counter T12) is only used to identify each of the blades 111 to 115 with respect to the other blades. Thus, the detection of the damage of the blades described later does not comprise here a simple observation or a detection of a variation of the interval At between the pulses measured by each blade tip timing sensor 71 between the blades 111.

[0155] The at least one blade tip timing sensor 71 can be used to measure the revolutions per minute (rpm) of the engine 10 of the aircraft.

[0156] Each blade tip timing sensor 71 can be a capacitive, inductive, eddy current type or optical probe, these different types of sensors being robust, accurate and not bulky.

[0157] An exemplary implementation of a method for detecting a damage of one or several blades 111 constituting an impeller equipped with blades, implemented by the damage detection assembly 20, will now be described.

[0158] As Figure 8As shown, the method comprises a step El of measuring the revolutions per minute (rpm) of the engine 10, implemented by the acquisition device 7. As mentioned above, the measurement of the revolutions per minute (rpm) of the engine 10 can be implemented by the blade tip timing sensor 71.

[0159] At the same time, the blade tip timing sensor 71 or 72 of the impeller 11 or 12 performs a measurement related to the time / moment of passage of the blade tip of each blade aligned with each sensor. Then, the processing device 11 performs a conditioning resulting from the measurement of the blade tip timing sensor 71 or 72. This conditioning consists in identifying in real time each blade in the time signal measured using the angular reference, extracting from the temporal signal the passage time (TOA) related to the identified blade, associating the extracted passage time thereof and the information related to its revolution to the identified blade (step E2).

[0160] For each acquisition of the passage time (TOA) of a blade, the main processing unit 711e calculates, via the calculation module 713, the deflection at the blade tip of this blade (step E3), that is to say the spatial deviation of the blade tip 111 with respect to the theoretical position of the blade at rest.

[0161] Then, during a step E4, the main processing unit 711e extracts, via the extraction module 712 shown in Figure 5 the dynamic component, that is to say separates it from the static component, for each calculated deflection. The extraction of the dynamic component is implemented using separation methods known from the prior art (for example: use of a high-pass filter average or extraction of high-frequency components).

[0162] The main processing unit 711e further implements, via the selection module 714, a selection step S of one or several revolutions per minute (rpm) ranges of the engine 10 for which it is assumed that all the blades of the impeller 11 equipped with blades are synchronized, that is to say that it is assumed that they have the same vibratory behavior for identical revolutions per minute (rpm) ranges of the engine 10. Here, the revolutions per minute (rpm) ranges of the engine 10 are pre-identified with respect to a reference database (for example the database Dl) to ensure that all the blades have the same vibratory behavior when they pass in alignment with the blade tip timing sensor 71 or 72.

[0163] In order to identify any damage to one or several blades for each revolution per minute (rpm) range of the engine 10 selected during the selection step S, the processing device 11 further comprises a processing module 715 which takes as input the dynamic components selected by the selection module 714.

[0164] The processing module 715 is configured to determine any change in the dynamic behavior of each blade by determining the changes in the dynamic components of each blade and by correlating these changes with the reference database (step E5). Moreover, the result of the determination step E5 is added to the monitoring database (here database D2). Thus, the determination step E5 can be seen as a step of analyzing the dynamic vibration behavior of each blade for each engine revolutions per minute (rpm) range selected during the selection step S.

[0165] Then, the main processing unit 711 e proceeds to a comparison step E6, after the determination step E5, via the comparator 716. The comparison step E6 consists in comparing each detected change in the dynamic component of the deflection of the blade 111 (that is to say each change in its dynamic behavior) with one or several threshold values previously recorded in the reference database Dl.

[0166] During this step E6, the detected change in each dynamic component of the blade 111 (and thus in the dynamic behavior) is in particular compared with a first change threshold value, which indirectly corresponds to the health state of the blade. This first threshold value is related to a second threshold value which relates to the change in the natural frequency of the blade 111, up to this threshold value corresponding to the damage of the blade 111.

[0167] The first and second threshold values are determined and then recorded in the reference database Dl during an initial learning phase E9.

[0168] Thus, the detection of a change in the dynamic component of the deflection of the blade 111 (that is to say, in its dynamic behavior) is here related to the indirect detection of a drift in the natural frequency of this blade 111 which exceeds a predetermined threshold value reflecting its damage.

[0169] Thus, if the change in the dynamic component of the deflection / dynamic behavior of the blade 111 is greater than the first change threshold value, this means that the natural frequency of the blade 111 itself has a drift reflecting the damage of the blade 111. Indeed, the damage of the blade 111 causes a drift in its natural frequency and thus in the dynamic component of its deflection.

[0170] Thus, when the comparator 716 detects that the change in the dynamic component of the deflection / dynamic behavior of the blade 111 is greater than or equal to the first threshold value, the blade 111 is identified (step E7) as being damaged.

[0171] Then, an alert is emitted to the alert device 9 (step E8) indicating the damage of the blade 111 (via for example, a sound and / or a display device). Similarly, a message to be sent or made available for maintenance can be triggered during the alert emission.

Claims

1. A method of monitoring torsion of a rotating shaft on an aircraft turbine engine based on measurements from at least three sensors, wherein, The at least three sensors comprise a first sensor, a second sensor and a third sensor distributed along the rotating shaft, the at least three sensors dividing the shaft into at least two shaft sections, the method comprising: - for each sensor, a step of measuring a parameter dependent on the rotation of the shaft, - for each pair of achievable sensors, a step of calculating a parameter related to the torsion of the shaft, wherein the achievable sensors comprise the first sensor and the second sensor, the first sensor and the third sensor and the second sensor and the third sensor, - a step of comparing the different calculated parameters related to the torsion of the shaft with a reference, - at the end of the comparison step, a step of detecting a damage on a shaft section, and - a step of indicating the location of the damage on the shaft from the shaft section for which a damage has been detected.

2. The method of monitoring torsion of a rotating shaft on a turbine engine of an aircraft based on measurements from at least three sensors of claim 1 wherein, At least one of the sensors for locating the damage is a sensor permanently installed on the turbine engine.

3. Method for monitoring the torsion of a rotating shaft on a turbine engine of an aircraft based on measurements from at least three sensors according to claim 1 or 2, comprising a preliminary step of installing at least one removable autonomous modular sensor, at least one of the sensors for locating the damage being a modular, autonomous and removable sensor.

4. Assembly for monitoring the torsion of a rotating shaft on a turbine engine of an aircraft, the assembly comprising: - at least three sensors, wherein the at least three sensors comprise a first sensor, a second sensor and a third sensor for measuring a parameter dependent on the rotation of the shaft, the sensors being distributed along the rotating shaft so as to divide the shaft into at least two shaft sections, - a calculation device configured to calculate a parameter related to the torsion of the shaft for each pair of achievable sensors, wherein the achievable sensors comprise the first sensor and the second sensor, the first sensor and the third sensor and the second sensor and the third sensor, - a comparison device configured to compare the different calculated parameters related to the torsion of the shaft with a reference, - a device for detecting a damage on a shaft section from the information transmitted by the comparison device, and - a device for indicating the location of the damage on the shaft, the device being configured to indicate the damaged section from the indication of the shaft section for which a damage has been detected by the detection device.

5. The assembly for monitoring torsion of a rotating shaft on an aircraft turbine engine of claim 4, wherein, At least one of the three sensors for locating the damage is a modular, autonomous and removable sensor.

6. The assembly for monitoring torsion of a rotating shaft on an aircraft turbine engine of claim 4 or 5, wherein, Each sensor is chosen from among a magnetic sensor, an acoustic sensor, a capacitive sensor and an optical sensor.

7. A turbine engine configured to receive an assembly for monitoring the torsion of a rotating shaft on a turbine engine of an aircraft according to any one of claims 4 to 6, the turbine engine comprising a casing and an opening of the casing for accessing each sensor.

8. The turbine engine of claim 7, wherein, At least one of the sensors is a sensor permanently installed on the turbine engine.

9. An aircraft comprising at least one turbine engine according to any one of claims 7 or 8.

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