Modular autonomous components for detecting the angular position of impeller blades and modular autonomous components for detecting damage to turbine engine impeller blades

Abstract

A modular autonomous assembly (1) for detecting the angular position of impeller blades, the assembly being intended to be mounted on a turbine engine (10), the assembly (1) comprising at least one power supply (711b, 71b, 72b) allowing the elements of the detection assembly (1) to operate independently of the turbine engine on which it is intended to be carried, at least one first sensor (71) intended to be associated with a first impeller, at least one second sensor (72) intended to be associated with a second impeller, and a main housing (711) comprising a processing unit (711e) and storage means (711c).

Description

Technical Field

[0001] The present invention relates to the field of aircraft engine monitoring, and more particularly to the individual identification of blades in a blading group, in particular for detecting possible damage or imbalance on one or more movable blades on one or more impellers of an aircraft engine. Background Art

[0002] The fans of the new generation of aircraft engines are equipped with composite blades. Integrating these blades into the fan can significantly improve its performance and save non-negligible mass.

[0003] However, monitoring the health of composite blades has proven to be complex.

[0004] While a simple visual inspection of metal blades can directly detect possible damage, this type of inspection has proven to be limited for composite blades. For example, impacts on composite blades can cause delamination and internal damage that is not visible to the naked eye and is therefore more difficult to detect.

[0005] Composite blades, as products with high added value, are highly desirable for conditional maintenance to be planned in advance to reduce delays and costs in aircraft ground maintenance. Therefore, such maintenance planning requires high-performance detection and identification of any possible damage to the blades.

[0006] One known method for detecting blade damage involves the use of blade tip timing sensors. These sensors detect and count the passage of the blade relative to a time reference. The tip timing sensor measurements are then used to calculate the natural frequency of each blade, which provides information about the blade's health.

[0007] In practice, this approach requires a large number of blade tip timing sensors to perform measurements, as well as significant computational resources to determine the natural frequency of each blade. Therefore, this solution is only suitable for test benches where integration constraints (e.g., volume, mass, available computational resources) are small. However, given the integration constraints and the required computational resources, this type of solution is not transferable to systems carried on aircraft. Therefore, in-flight monitoring of blade health is not possible without anchoring the aircraft's engine to the ground.

[0008] Another known solution for detecting damage involves monitoring the natural frequency of each blade through a "ping test." In this test, each blade is excited with a shock-type pulse, and measuring the pulse frequency response of each blade can detect possible damage. However, this type of method also requires the aircraft engine to be fixed.

[0009] There is a need for an onboard solution on an aircraft that allows checking the health of each blade and provides monitoring of its flight health. Generally speaking, this need concerns all types of blades, the latter being made of composite materials as well as any other material, such as metal.

[0010] Individual identification of blades in a blading group is crucial for balancing the blades and monitoring their health. This identification can be performed by detecting information called "Top-Turn."

[0011] The top-turn is a fixed reference point relative to a rotating element (such as the low-pressure or high-pressure shaft), such as an engine casing. This position tells us the angular position of the low-pressure shaft relative to the casing (in a fixed reference frame).

[0012] In fact, the rotors of aircraft engines must be balanced to ensure good adherence to the engine's vibration limits. To do this, it is necessary to compensate for measured imbalances or misalignments by positioning one or more masses at precise angular positions in a fixed reference frame. Top-Turn can then define the connection locations of these masses. This manual identification must be consistent with the supporting machine (onboard system) identification.

[0013] Typically, one method for detecting top-turns involves using a sensor, known as a top-turn sensor, that detects the passage of a tooth or blade facing it, particularly a single tooth of a blade assembly (here, an impeller). This type of sprocket is known as a tonic sprocket and is characterized by an anomaly, such as an excess of material or a partial absence of material on the sprocket. This anomaly can be detected using, for example, a capacitive sensor or a Hall effect sensor. Detecting this anomaly allows the reference angular position of the entire sprocket to be determined.

[0014] The tone wheel has no other function other than to provide this angular reference and serve as a point from which to measure the rotational speed of the rotating part to which it is attached.

[0015] The tone wheel does not see the flow. It has no so-called aerodynamic function and therefore does not participate in the propulsion of the engine.

[0016] However, this tone wheel has an impact on the mass of the aircraft, especially when it rotates, and also on integration, considering that this particular component is added to the low-pressure shaft of the engine and that it is necessary to integrate the sensor into the tone wheel, especially with regard to the difficulties associated with implementing tolerances.

[0017] Therefore, it is advantageous not to integrate a tone wheel and to obtain the Top-Turn information by other methods.

[0018] From document US 2012 / 148400, it is known to detect a Top-Turn based on the detection of singularities on a blade in a blade arrangement other than a tone wheel, so as to be able to eliminate it.

[0019] Document EP 2 661 611 also discloses a system for replacing speed measurement systems using a tone wheel. If a shaft is sectioned, the tone wheel located upstream of the break is unable to measure the turbine's rotational speed. This information is crucial for regulation to prevent the turbine from overspeeding.

[0020] In this method, in order to obtain information, a blade must have different profiles in order to produce different pressure curves.

[0021] A method for monitoring FOD in a turbofan engine using Top-Turn information is also known from document US Pat. No. 8,528,317: the "beep per revolution" of a tone wheel.

[0022] Another known method is to identify top-turns by differences in the distribution of tone wheel teeth. These differences in proximity affect the time of passage detected by the top-turn sensor. Through algorithmic processing, these differences in time increments can identify differences in the distribution of blades, and thus the angle reference.

[0023] All the known and mentioned solutions above suggest achieving the Top-Turn by creating singularities in the blade arrangement or the tone wheel.

[0024] The introduction of singular blades in turbine engines has various disadvantages, such as the need to develop specific components and provide production management for different blades, resulting in different behavior compared to other blades in the turbine engine. There are also problems with turbine engine certification and increased complexity in turbine engine maintenance, as well as the aerodynamic and vibration disturbances caused by the singularity of the singular blade, and the resulting performance degradation.

[0025] The known method also has the disadvantage of producing an uneven distribution of blades, i.e., irregular angles relative to the other blades. The blades can be distributed unevenly within the blading group, but this also leads to manufacturing limitations and aerodynamic disturbances that negatively affect engine performance.

[0026] The above-mentioned known method also has the disadvantage that the sensor must have sufficient bandwidth to detect the passage of all blades for all speed ranges used. In fact, if the speed is too fast or the number of blades is too large, the capacitive sensor will not be able to distinguish the blades and optical sensors, for example, will need to be used.

[0027] Finally, the known methods and systems described above also have the disadvantage of requiring the return of information related to Top-Turn via a computer capable of processing it. This raises the question of the proposed monitoring independence relative to a FADEC (Full Authority Digital Engine Control) type system, in particular the digital engine control unit ECU (Engine Control Unit) or the unit for monitoring the engine's health status EMU (Engine Electric Unit), as well as other integration problems and corresponding quality impacts, since the proposed solutions are intended to be permanently integrated into the turbine engine. Summary of the Invention

[0028] The purpose of the present invention is to remedy the above-mentioned drawbacks by providing a detachable solution independent of the turbine engine's computer and the turbine engine's power supply, and allowing the generation of a Top-Turn angle reference and the storage of the generated signal.

[0029] To this end, the invention proposes a modular autonomous assembly for detecting the angular position of impeller blades, which assembly is intended to be installed on a turbine engine.

[0030] According to a general characteristic of the invention, the assembly comprises at least one power source allowing the elements of the detection assembly to operate independently of the turbine engine intended to host it, as well as at least one first sensor intended to be associated with a first impeller, at least one second sensor intended to be associated with a second impeller, and a main housing including a main processing unit and memory means.

[0031] The present invention also allows for a solution to be provided in the form of a kit, independent of any turbine engine, comprising a main housing and the various sensors. Thus, the kit according to the present invention can be mechanically connected to a turbine engine to perform its task of detecting angular position, while remaining independent of the turbine engine in terms of power supply due to the power supply and information processing capabilities due to the main processing unit—in other words, independent of the turbine engine's computer. This does not affect the operation of the turbine engine.

[0032] The autonomy of the modular measurement assembly powered by the mains allows for intermittent installation of the modular assembly on the turbine engine, thus reducing quality impacts over time.

[0033] According to the first aspect of the autonomous modular detection assembly, the main housing, the at least one first sensor and the at least one second sensor may each comprise reversible manual connection means allowing them to be removably mounted on the turbine engine.

[0034] Manual couplings are devices that allow the connection of turbine engines without the use of any tools. Thus, each element of the assembly can be easily installed and removed from the turbine engine without the use of any tools.

[0035] The mass of such a test assembly is less than 1 kg. The modularity of the assembly, due to its removability, allows to have only intermittent mass impacts on the turbine engine and, by extension, on the aircraft, in the long term, which are related to the load-bearing of an assembly of this type on the turbine engine. In fact, the monitoring of the turbine engine blade assembly does not necessarily have to be carried out continuously. Should the degradation of the health state of the blade assembly to be identified be permanent, intermittent checks, after or during flights, for example every three flights or after an event (such as the ingestion of foreign objects), are sufficient. The entire assembly is monitored during the component load-bearing check before removal from the turbine engine.

[0036] Furthermore, the modularity of the onboard components as a plug-and-play kit enables them to be installed intermittently on at least one turbine engine, thus avoiding the need to install two onboard systems on the same aircraft.

[0037] The modularity of the components also allows the option of using components only on the ground, which avoids the need for component certification, which is necessary for any equipment carried in flight.

[0038] The memory device allows the data collected by the sensors to be stored so that they can be processed in flight by the processing unit of the main housing. The memory device also allows the necessary and appropriate information to be carried to adapt the reference datum to each stage of the blade assembly being monitored, thus allowing in-flight inspections.

[0039] For example, using four sensors and one main housing, four levels of the same shaft or two different shafts can be monitored.

[0040] According to a second aspect of the autonomous modular detection assembly, each of the first and second sensors may comprise a detection module, a local processing module and communication means configured to transmit measurement values ​​of the respective sensor to the main processing unit.

[0041] Sensors can have different configurations to suit the different environments of turbine engines. The temperature difference between the rear of the turbine fuselage and the compressor is about 200 to 250 degrees Celsius. Therefore, certain sensors can be configured to withstand the highest expected temperature.

[0042] According to a preferred embodiment of the second aspect, each of the first and second sensors further comprises a power supply for the sensor, and the communication means is a wireless communication means.

[0043] Using wireless communication means and power supplies for each sensor and the main housing facilitates mounting of the different components of the assembly, as the sensors can be connected to the main housing, thereby passing cables between the different components.

[0044] According to a third aspect of the autonomous modular detection component, wherein the component is intended to be installed on a turbine engine, the turbine engine comprising a first impeller comprising a first number of blades and a second impeller comprising a second number of blades, each of the two impellers having an airflow passing therethrough and being directly or indirectly coupled to each other, the first number of blades of the first impeller and the second number of blades of the second impeller being different and prime to each other, each of the sensors being configured to generate a signal each time a blade of the impeller in front of the sensor passes by, and the main processing unit being configured to determine a time interval between a blade detection of the first impeller and each blade detection of the second impeller.

[0045] This configuration thus allows the angular position of the turbine engine impeller blades to be detected without a tone wheel, which can save rotating mass and volume, or, in the absence of singularities on the impeller blades, avoid the introduction of aerodynamic disturbances in the turbine engine's airflow. This detection is achieved by using the time information of two blade arrangements having different numbers of blades.

[0046] Furthermore, this testing can be done both on the ground and in flight.

[0047] This configuration advantageously utilizes the existing blades on the turbine engine shaft, dedicated to propulsion. Thus, by comparing the time signals between the two blades, a top-turn type angular reference can be obtained. In fact, an angular reference can be formed based on the blade pitch of the two impellers moving relative to each other.

[0048] More specifically, by continuously comparing the passage time of the blades of the first impeller with the passage time of the blades of the second impeller, a pattern, or signature, can be identified. This signature allows each specific blade to be identified and defined as a Top-Turn.

[0049] If the first and second impellers are driven by the same shaft, they are directly driven. If the first and second impellers are driven by a first shaft and a second shaft respectively, and the first shaft and the second shaft are mechanically connected through a reduction gear, then both impellers are indirectly driven by the same shaft.

[0050] Furthermore, the assembly may comprise a determination module for determining a rotational speed of the shaft or shafts driving the two impellers, the determination of the relative angular position taking into account the determined rotational speed.

[0051] The signature changes depending on the shaft speed. The gaps are related to the distribution of the blades, and they can be normalized using the rotational speed of a known number of blades. In this sense, the Top-Turn detection logic is also independent of the shaft rotational speed.

[0052] According to a preferred embodiment of the third aspect, the component may include a first sensor and a second sensor to be installed on a first impeller of the turbine engine, and a third sensor and a fourth sensor to be installed on a second impeller of the turbine engine, the first and second sensors being of two different types, and the third and fourth sensors being of two different types, the types of sensors being particularly selected from optical, magnetic and capacitive types.

[0053] This pair of parameters, including the number of blades on the disk and the speed of the shaft, determines the sensor technology to ensure good resolution in the acquisition of the transit time and in the differentiation of the detected blades.

[0054] According to a fourth aspect of the autonomous modular detection assembly, the main housing may further include a clock module, and the at least one first sensor and the at least one second sensor are synchronized on the clock module.

[0055] The synchronization of sensors on the same time base can improve the measurement accuracy of detecting the time interval between blade passages.

[0056] According to a fifth aspect of the autonomous modular detection assembly, the at least one first sensor and the at least one second sensor may have a frequency bandwidth corresponding to a rotational speed of a shaft of the detection blade.

[0057] In another aspect of the invention, an assembly for detecting damage to turbine engine impeller blades is proposed, comprising a modular autonomous assembly for detecting the angular position of the impeller blades and a warning device.

[0058] In another aspect of the invention, a turbine engine is proposed, which is configured to receive a modular autonomous assembly for detecting the angular position of an impeller blade as described above, comprising a recess for each element of the main casing of the assembly, the at least one first sensor and the at least one second sensor, and a hatch for accessing the recess.

[0059] The connection areas of the elements or grooves of the assembly provided on the turbine engine guarantee easy access and allow installation and removal of the kit (i.e. assembly) in the same order of magnitude as an LRU (Light Replaceable Unit) component, i.e. 20 minutes, excluding manipulation of the covering.

[0060] According to a first aspect of the turbine engine, the turbine engine may include a first impeller including a first number of blades and a second impeller including a second number of blades, each of the two impellers having an airflow passing therethrough and being directly or indirectly coupled to each other, the first number of blades of the first impeller and the second number of blades of the second impeller being different and being prime numbers to each other.

[0061] According to a second aspect of the turbine engine, the first number of blades is preferably at least equal to two blades and the second number of blades is at least equal to three blades.

[0062] Another object of the invention is to propose an aircraft comprising at least one turbine engine as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A modular autonomous assembly for detecting the angular position of an impeller blade according to one embodiment of the present invention is schematically shown.

[0064] Figure 2 A turbine engine according to one embodiment of the present invention is schematically shown, on which a modular autonomous assembly is installed for detecting Figure 1 Angular position of the impeller blades.

[0065] Figure 3 An assembly for detecting damage to moving blades of an aircraft turbine engine wheel having a first configuration is schematically shown.

[0066] Figure 4 An assembly for detecting damage to moving blades of an aircraft turbine engine impeller having a second configuration is schematically shown.

[0067] Figure 5 A flow chart illustrating a method of detecting the angular position of turbine engine impeller blades.

[0068] Figure 6 A flow chart shows a method for detecting damage to one or more movable blades constituting an impeller of an aircraft engine, the method comprising detecting the angular position of the impeller blades according to one embodiment of the present invention. DETAILED DESCRIPTION

[0069] The present invention is generally applicable within the context of predictive maintenance services performed by aircraft engine manufacturers.

[0070] Figure 1 A modular autonomous assembly 1 for detecting the angular position of an impeller blade according to one embodiment of the present invention is schematically shown, the detection assembly 1 being intended to be mounted on a turbine engine 10 .

[0071] exist Figure 1 In the embodiment shown, the modular autonomous detection assembly or kit 1 comprises a main housing 711, a first sensor 71 and a second sensor 72. In a variation, the assembly may comprise more than two sensors.

[0072] The main housing 711 includes a communication unit 711a, a main power battery 711b, a storage unit 711c, two reversible connection clips 711d and a main processing unit 711e.

[0073] A portion of the storage unit 711c is a random access memory of the RAM type dedicated to calculations, and another portion of the storage unit 711c is a read-only memory of the NVRAM type for storing results and configuration parameters of the main processing unit 711e such as a processor.

[0074] The reversible manual connection clamp allows the main housing 711 to be connected to the turbine engine 10 in an easily removable manner without the use of tools. The connection clamp 711d is a physical multi-point connection for mechanical connection to the turbine engine 10.

[0075] Each sensor 71 and 72 comprises a detection module, respectively indicated as 71 a and 72 a, such as a blade tip timing sensor of the capacitive, optical, inductive or pressure type, a local battery, respectively indicated as 71 b and 72 b, a communication module, respectively indicated as 71 c and 72 c, allowing communication with the communication unit 711 a of the main housing 71, two reversible connection clips, respectively indicated as 71 d and 72 d, and a local processing unit, such as a processor, respectively indicated as 71 e and 72 e.

[0076] The reversible manual connection clamp 71d or 72d allows the sensor 71 or 72 to be connected to the turbine engine 10 in an easily removable manner without the use of tools. The connection clamp 71d or 72d is a physical multi-point connection for mechanical connection to the turbine engine 10.

[0077] The information collected by the detection module 71a or 72a of the sensor 71 or 72 is transmitted to the local processing unit 71e or 72e, which prepares the signal before it is transmitted by the communication module 71c or 72c to the communication unit 711a of the main housing 711. The local processor 71e or 72e is capable of converting the raw information collected from the detection module 71a or 72a at a frequency of several tens of kHz into a transmittable signal (digitization, compression, pre-processing, blade passage detection).

[0078] exist Figure 1 In the illustrated embodiment, the communication modules 71c or 72c of the sensors 71 and 72 are adapted for wireless transmission and reception of information, and the communication unit 711a of the main housing 711 is configured and adapted to receive information transmitted via a wireless communication network.

[0079] In one variation, the detection assembly 1 may include a single power source, such as a battery, located in the main housing 711 and providing power to the sensors 71 and 72 via wired connections.

[0080] Figure 2 FIG schematically shows a turbine engine 10 according to an embodiment of the present invention, on which a detection device for detecting Figure 1Autonomous modular assembly for the angular position of impeller blades.

[0081] exist Figure 2 In the illustrated embodiment, a detection kit 1 comprising only a first sensor 71 and a second sensor 72 is installed on a turbine engine 10. The first sensor 71 is mounted on the nacelle of the turbine engine 10, facing the fan 11, to monitor the health of the fan 11's blades. The second sensor 72 is mounted on the nacelle of the turbine engine 10, facing the blades 12 of the low-pressure compressor stage. The main casing 711 itself is mounted on the fan casing of the turbine engine 10, located in the low-temperature zone.

[0082] The first sensor 71 and the second sensor 72 are mounted in a recess 70 on the turbine engine, which is provided with a hatch for access from the nacelle. The access to the recess can be easily opened and closed to install or remove the sensors 71 and 72.

[0083] The main casing 711 can also be positioned to provide a dedicated access hatch for this purpose. The access hatch can also be shared with a recess dedicated to receiving another element of the turbine engine, such as a hatch for accessing fuel.

[0084] exist Figure 2 In the embodiment shown, turbine engine 10 includes three other locations 70 for receiving sensors similar to first and second sensors 71 and 72 .

[0085] The first and second of the three other positions 70, in Figure 2 The third of the three free positions 70 is located on the nacelle of the turbine engine 10, facing the high-pressure compressor stage 21.

[0086] Due to these positions 70 , in another configuration, two further sensors may be provided to monitor the high-pressure compressor stage 21 and the high-pressure turbine stage 22 coupled by the drive shaft 19 .

[0087] Figure 3 An assembly 20 for detecting damage to a bladed wheel 11 or a moving blade of an impeller of an aircraft turbine engine 10 having a first configuration is schematically shown.

[0088] The component 20 for detecting damage includes a component for detecting Figure 1 Kit 1 and warning device 9 for the position of the middle impeller blades.

[0089] To improve Figure 3 For ease of reading, not all components of Kit 1 are shown. Kit 1 includes Figure 1All elements described in, namely the main housing 711, the main housing including in particular a main processing unit 711e and a storage unit 711c in the form of one or more databases D1, D2, a first sensor 71 and a second sensor 72.

[0090] In addition to detecting the top turn, the first sensor 71 and the second sensor 72 of the component 1 for detecting the blade position also form a device 7 for collecting data of the component 20 for detecting damage.

[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 performing damage detection. Thus, the main processing unit is configured to execute a computer program comprising code instructions designed to implement the acquisition, signal processing, analysis, and alarm algorithms of the damage detection method according to the present invention.

[0092] The acquisition device 7 is configured to acquire a time signal S1 relating to moving blades 111 to 115 of an impeller 11 (for example an impeller of a fan or any other impeller of the engine 10 ).

[0093] Advantageously, the acquisition means 7 use the “tip timing” technique to measure the transit times / instantaneous TOA (“Time of Arrival”) of the moving blades 111 to 115 .

[0094] like Figure 2 As shown, the first sensor 71 of the acquisition device 7 is a blade tip timing sensor, which is mounted on the housing of the engine 10 and aligned with the impeller 11 of the fan so as to acquire a time signal S1 specific to the first sensor 71 .

[0095] More specifically, the tip timing sensor 71 detects and counts the passage of the tips of the blades 111 to 115 relative to a time base. Thus, the tip timing sensor 71 can measure the current passage time between blades 111 to 115 relative to a reference point (also referred to as "Top-Turn"). A specific time of passage (TOA) for each blade 111 to 115 can then be derived from the measured data by the main processing unit 711 e, in this case, by a calculation module 713 within the main processing unit 711 e.

[0096] In other words, the blade tip timing sensor 71 allows for acquisition of a measurement value related to the time / instant of passage of the blade tip of each active blade 111 to 115, which is consistent with a reference area of ​​the impeller 11. Furthermore, in order to limit the risk of losing a blade tip timing sensor 71 when multiple sensors 71 are used on the same impeller, the sensors 71 can be positioned so as to maximize their azimuth distance, thereby separating them from one another as much as possible. Thus, in the event of a localized failure of a sensor 71 (e.g., impact of debris on a blade 111, contamination of a sensor 71), the risk of all sensors 71 being affected is minimized.

[0097] In normal operation, blades 111 to 115 will regularly pass in front of the same blade tip timing sensor 71. At a given speed, sensor 71 will measure the time interval Δt between two consecutive blade passes.

[0098] On the other hand, a change in the state of the blade, such as wear due to ingestion of foreign matter FOD (“foreign object damage”), can be converted into a change in the position of the blade when passing in front of the at least one sensor 71 .

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

[0100] In this embodiment, the angle reference is provided by the kit 1 for detecting Figure 1 The "Top-Turn", which in particular allows to avoid the use of a tone wheel.

[0101] The component 1 for detecting "Top-Turn" is configured to detect the relative angular position of the blades of a first impeller (such as the impeller 11 of a fan) and a second impeller 12. The damage of the blades of the first impeller is monitored by a first sensor 71. The same air flow passes through the first and second impellers 11 and 12. Figure 3 In the embodiment shown, it is driven by the same shaft 19 as the turbine engine 10 .

[0102] Damage to the blades of the second impeller 12 may also be monitored in the same manner as for the first impeller 11 by means of other blade tip timing sensors, such as the second sensor 72 , mounted opposite the second impeller 12 .

[0103] First impeller 11 includes a first number of blades N1, and second impeller 12 includes a second number of blades N2. The first number of blades N1 of first impeller 11 and the second number of blades N2 of second impeller 12 are different and have no common divisor. Therefore, the first and second numbers of blades N1 and N2 are prime numbers to each other. The blades are regularly distributed on each impeller 11 and 12. Therefore, on the same impeller 11 or 12, two adjacent blades are separated by the same angular interval.

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

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

[0106] Each time a blade of first impeller 11 passes in front of first onboard sensor 71, first onboard sensor 71 returns a first time signal S1. Each time a blade of second impeller 12 passes in front of first onboard sensor 72, second onboard sensor 72 returns a second time signal S2. The time interval between each detection, i.e., ΔT1 for first impeller 11 and ΔT2 for second impeller 12, depends on the rotational speed of shaft 19 and the number of blades on impellers 11 or 12, respectively.

[0107] Figure 4 An assembly 20 for detecting damage to moving blades of an impeller 11 of an aircraft turbine engine 10 having a second configuration is schematically shown.

[0108] Figure 4 The second configuration of the turbine engine 10 is shown with Figure 3 The first configuration of the turbine engine 10 shown differs in that the air flows (possibly different) pass through the first and second impellers 11 and 12 , respectively, which are driven by two different shafts 190 and 195 , interconnected by a reduction gear 198 .

[0109] Figure 5 FIG2 is a flow chart of a method for detecting the angular position of a turbine engine impeller blade according to an embodiment of the present invention. The assembly 1 for detecting top-turn can implement the method for detecting top-turn.

[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 the second step 210 , the second sensor 72 detects the passage of each blade 121 to 127 of the second impeller 12 .

[0112] One disk is equivalent to 2π radians. Therefore, by relating it to the rotation speed of the shaft, we get 1rpm = 2π / 60rad.s -1 .

[0113] For a fixed rotational speed, hereinafter expressed as RPM, the time interval between two consecutive blade passes of an impeller having N blades in front of a sensor associated with the impeller is determined by the following formula.

[0114]

Mathematical formula 1

[0115]

[0116] Thus, for the first impeller 11 and the first dedicated sensor 71 facing it, we obtain:

[0117]

Mathematical formula 2

[0118]

[0119] For the second impeller 12 and the second dedicated sensor 72 facing it, we obtain:

[0120]

Mathematical formula 3

[0121]

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

[0123] exist Figure 3 and Figure 4 In the embodiment shown, the first impeller 11 includes five blades, or N1=5, labeled 111 to 115, and the second impeller 12 includes seven blades, or N2=7, labeled 121 to 127. For ease of calculation, the speed of the shaft is considered to be equal to 60 / 2π revolutions per minute, or RPM=60 / 2π revolutions.

[0124] With these characteristics, and taking into account that for simplicity the sensors have the same angular position, the following list of passage times of the blades at the completion of the first step 200 and the second step 210 is obtained:

[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 blade is not necessarily facing the sensor initially, which introduces a delay before the first detection.

[0128] In a third step 220 , the main processing unit 711 e calculates a time interval πt between the passage of one blade of the first impeller 11 and each blade 121 to 127 of the second impeller 12 .

[0129] If in Figure 3 In the first embodiment shown, the two impellers 11 and 12 are driven by the same shaft 19, and the arrival times of the blades 111 to 115 of the first impeller 11 are compared with the arrival times of the blades 121 to 127 of the second impeller 12, resulting in this matrix:

[0130]

Table 2

[0131]

[0132] The values ​​of the matrix correspond to the differences between the arrival times of the blades 111 to 115 of the first impeller 11 and the arrival times of the blades 121 to 127 of the second impeller 12 , ie the time interval denoted ΔT.

[0133] In a variant, the calculation of the time interval ΔT may take into account the deceleration coefficient of the deceleration device 198 (if present).

[0134] For example, in Figure 4 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 driven by a shaft with a coefficient C 减速 Therefore, for the first impeller 11 and the first dedicated sensor 71, we obtain:

[0135]

Mathematical formula 4

[0136]

[0137] For the second impeller 12 and the second dedicated sensor 72 facing it, we obtain:

[0138]

Mathematical formula 5

[0139]

[0140] If a similar comparison is performed in the second embodiment, but this time by calculating the coefficient corresponding to C 减速 The difference between the first time which is the product of 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 results in the same matrix as shown in Table 2.

[0141] Therefore, the matrix table provides as many angular references as needed. As shown in the matrix table, the blades are no longer aligned from one impeller to the other. If the two impellers are aligned so that one blade of each impeller is aligned with the other, there is a cell in the table with a difference of zero.

[0142] Algorithms can then use this type of database.

[0143] In a variant, the calculation of the time interval ΔT can be normalized with respect to the speed of rotation of the shaft 19 driving the two impellers 11 and 12 , so that the calculation is independent of the speed of rotation.

[0144] Then, 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 relative to the angular position of the blades 121 to 127 of the second impeller 12 based on the value of the time interval ΔT and the speed values ​​of the first and second impellers 11 and 12.

[0145] exist Figure 1 and Figure 2 In the example illustrated in the table above, at the end of a turn, the last two blades 115 and 127 with the smallest time interval Δt are detected. However, this result is still random, as it depends on the offset of the first detection. The offset difference between the two impellers 11 and 12 is itself related to the installation of the first and second impellers 11 and 12 on the shaft 19, as well as the angular position of the first and second sensors 71 and 72. Therefore, this offset is related to the production and assembly of the turbine engine 10.

[0146] With the first and second sensors 71 and 72 aligned to the same angular reference, the offset is only related to the mounting of the impellers 11 and 12 on the shaft 19 and their relative alignment.

[0147] This offset is characteristic of turbine engine 10, and the resulting alignment between the blades of one impeller and the other is inherent to turbine engine 10. This alignment, shown here as the time of passage of the blades relative to the blade tip timing sensor, is ultimately a temporal signature of this alignment of the blades.

[0148] Finally, in a fifth step 240 , the main processing unit 711 e designates the blade of the first impeller 11 having the smallest time gap Δt with the blade of the second impeller 12 as the angle reference, ie, Top-Turn.

[0149] As described above, the fifth blade 115 of the first impeller 11 and the seventh blade 127 of the second impeller 12 are most aligned.

[0150] This special arrangement can arbitrarily determine that the fifth blade 115 of the first impeller 11 is regarded as Top-Turn, that is, as an angle reference. According to the analysis of the above matrix table, another blade of the first impeller 11 can be arbitrarily designated as Top-Turn.

[0151] The alignment of the blades of one impeller to the other remains the same as it relates to the assembly and the number of blades on each impeller. Identification of a top-turn only requires the deployment of an algorithm to identify a turn.

[0152] Thus, in each flight of an aircraft including a turbine engine 10, the first turn of the engine 10 can be used to reconstruct the Top-Turn. Each detection of the blade selected as the Top-Turn will then give a time reference (in terms of tip timing) and an angular reference for the Top-Turn.

[0153] The system 20 for detecting blade damage seeks to detect a sustained degradation in the performance of one or more blades 111 to 115 associated with the damage, rather than a simple, temporary perturbation observable on signal S1. Therefore, the aforementioned angle reference (Top-Turn T12) is used only to identify each blade 111 to 115 relative to the other blades. Consequently, the blade damage detection described below does not involve simply observing or detecting a change in the pulse spacing Δt measured by each blade tip timing sensor 71 between blades 111.

[0154] At least one blade tip timing sensor 71 may be used to measure the rotational speed of the aircraft engine 10 .

[0155] Each blade tip timing sensor 71 can be a capacitive type, an inductive type, a Foucault current type, or even an optical probe. These different types of sensors are durable, accurate, and require little space.

[0156] One embodiment of a method for detecting damage to one or more moving blades 111 constituting an impeller, implemented by the assembly 20 for detecting damage, will now be described.

[0157] like Figure 6 As shown, the method includes the step of measuring the rotational speed of the E1 engine 10 by means of the acquisition device 7. As mentioned above, the measurement of the rotational speed of the engine 10 can be accomplished by means of the blade tip timing sensor 71.

[0158] At the same time, the blade tip timing sensor 71 or 72 of the impeller 11 or 12 performs measurements related to the time / instant of passage of the tip of each active blade aligned with the sensor. The processing device 11 then conditions the measurements originating from the blade tip timing sensor 71 or 72. This conditioning involves identifying each blade in real time from the time signal measured by the angle reference, extracting the time of passage (TOA) associated with the identified blade from the time signal, and associating the extracted time of passage and information related to the number of turns of the blade with the identified blade (step E2).

[0159] For each acquisition of the blade's transit time (TOA), the main processing unit 711e calculates the deflection of the blade tip through the calculation module 713 (step E3), ie, the spatial clearance of the blade tip 111 relative to its theoretical static position.

[0160] Then, during a step E4, the main processing unit 711e processes the Figure 3 The extraction module 712 shown extracts the dynamic component of each calculated deflection, ie, isolates it from the static component. The extraction of the dynamic component is accomplished by isolation methods known in the art (eg, averaging, or using a high-pass filter to extract high-frequency components).

[0161] The main processing unit 711e further performs the step of selecting (S) one or more engine 10 speed ranges via the selection module 714, assuming that all blades of the impeller 11 are synchronized, i.e., assume that they have the same vibration behavior within the same engine 10 speed range. The engine 10 speed ranges are predetermined relative to a reference database (e.g., database D1) to ensure that all blades have the same vibration behavior when passing the blade tip timing sensor 71 or 72.

[0162] In order to identify possible damage to one or more blades in each selected range of speed of the engine 10 during the selection step S, the processing device 11 further comprises a processing module 715 having as input the dynamic components selected by the selection module 714 .

[0163] Processing module 715 is configured to determine (step E5) possible changes in the dynamic behavior of each blade by determining changes in the dynamic components of each blade and correlating these changes with a reference database. Furthermore, the results of determination step E5 are added to a monitoring database, here, database D2. Thus, determination step E5 can be considered a step for analyzing the dynamic vibration behavior of each blade within each engine speed range selected during selection step S.

[0164] The main processing unit 711e then performs a comparison step E6 after the determination step E5 via the comparator 716. The comparison step E6 consists in comparing each detected variation of the dynamic component of the deflection of the blade 111, ie each variation of its dynamic behavior, with one or more pre-recorded thresholds in the reference database D1.

[0165] During this step E6, in particular, each variation of the dynamic component detected for blade 111 (and therefore of its dynamic behavior) is compared with a first variation threshold value that indirectly corresponds to the state of health of the blade. This first threshold value is associated with a second threshold value related to the variation of the natural frequency of blade 111, the reaching of which is equivalent to damage to blade 111.

[0166] The first and second threshold values ​​are determined and then recorded in the reference database D1 during an initial learning phase E9.

[0167] Thus, the detection of changes in the dynamic component of the deflection of the blade 111, ie changes in its dynamic behavior, is here coupled with the indirect detection of deviations from the natural frequency of this blade 111 which, exceeding a predetermined threshold, translate into damage thereto.

[0168] Therefore, if the variation of the dynamic component of the deflection / dynamic behavior of the blade 111 is greater than the first variation threshold, this means that the natural frequency of the blade 111 itself has deviated, which translates into damage to the blade 111. In fact, damage to the blade 111 results in a deviation of its natural frequency and therefore a deviation of the dynamic component of its deflection.

[0169] Thus, when the comparator 716 detects a change in the dynamic component / dynamic behavior of the deflection of the blade 111 that is greater than or equal to the first threshold, the blade 111 is identified (step E7 ) as damaged.

[0170] The warning indicating damage to the blade 111 is then transmitted (step E8) to the warning means 9 (for example by sound and / or display means). Likewise, during the transmission of the warning, a message to be sent or available for maintenance may be triggered.

Claims

1. A modular autonomous detection assembly for detecting the angular position of a turbine engine blade, the modular autonomous detection assembly being configured to be removably mounted on a turbine engine, the turbine engine comprising a first impeller having a first number of blades and a second impeller having a second number of blades, each of the two impellers having an airflow passing therethrough and being directly or indirectly coupled to each other, the first number of blades of the first impeller being different from the second number of blades of the second impeller being prime to each other; in, The modular autonomous detection component includes: at least one power source allowing the elements of the modular autonomous detection assembly to operate independently of the turbine engine on which it is intended to be carried; at least one first sensor configured to be associated with the first impeller; at least one second sensor configured to be associated with the second impeller, and a main housing including a main processing unit and a storage device; Each of the first and second sensors is configured to generate a signal each time a blade of an impeller passes in front of the sensor, and the main processing unit is configured to determine a time interval between detection of a blade of the first impeller and each detection of a blade of the second impeller.

2. The modular autonomous detection assembly according to claim 1, wherein: The main housing, the at least one first sensor and the at least one second sensor each include reversible manual connection means allowing them to be removably mounted on the turbine engine.

3. The modular autonomous detection assembly according to claim 1, wherein: Each of the first and second sensors comprises a detection module, a local processing module and communication means configured to communicate the measurement values ​​of the respective sensor to the main processing unit.

4. The modular autonomous detection assembly according to claim 3, wherein: Each of the first and second sensors further comprises a power source for the sensor, and the communication means is a wireless communication means.

5. The modular autonomous detection assembly according to claim 1, wherein: The main housing further includes a clock module on which the at least one first sensor and the at least one second sensor are synchronized.

6. The modular autonomous detection assembly according to claim 1, wherein: The at least one first sensor and the at least one second sensor have a frequency bandwidth corresponding to detecting a rotational speed of a shaft of the blade.

7. An assembly for detecting damage to turbine engine impeller blades, comprising a modular autonomous detection assembly for detecting the angular position of a turbine engine blade and a warning device according to any one of claims 1 to 6.

8. A turbine engine comprising a modular autonomous detection assembly for detecting the angular position of a turbine engine blade according to any one of claims 1 to 6 or an assembly for detecting damage to a turbine engine impeller blade according to claim 7, said turbine engine comprising recesses for each of the main casing of said assembly, said at least one first sensor and said at least one second sensor, and hatches for accessing said recesses.

9. The turbine engine according to claim 8, comprising a first impeller including a first number of blades and a second impeller including a second number of blades, wherein airflow passes through each of the two impellers and the two impellers are directly or indirectly coupled to each other, and the first number of blades of the first impeller and the second number of blades of the second impeller are different and are prime numbers to each other.

10. Aircraft comprising at least one turbine engine according to any one of claims 8 to 9.

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