Method and system for the protection of a turbomachine and / or an operator in case a turbomachine overspeeds on a test bench

Abstract

The invention relates to a method for protecting a turbomachine and / or an operator in case a turbomachine overspeeds on a test bench. The invention makes it possible to improve the level of security and to ensure an autonomous and rapid intervention in order to protect both staff and the equipment.

Description

Method and system for protecting a turbomachine and / or an operator in the event of overspeed of a turbomachine in a test bench Technical field

[0001] The present invention relates to a method for protecting a turbomachine and / or an operator in the event of overspeed of a turbomachine in a test bench. The present invention also relates to a protection system for implementing such a method. Prior art

[0002] Conducting tests on a turbomachine, particularly in the aeronautical field, is a complex task that requires special attention to personnel safety and equipment preservation. These tests aim to evaluate the performance and reliability of the turbomachine in controlled environments that mimic real-life operating conditions. However, these tests present significant risks due to the nature of turbomachines and the complexity of the control systems.

[0003] Technical incidents that may occur during these tests are often related to operating errors or control software failures, which can cause unforeseen acceleration of the turbomachine beyond pre-established safety limits. Such accelerations can have serious consequences, including serious injuries to personnel on site and / or the total destruction of the tested device if maximum tolerated speeds are exceeded.

[0004] The test bench operator is responsible for shutting down the turbomachine in the event of technical incidents. This is not sufficiently reliable. Summary of the invention

[0005] In the context of the present invention, the test bench comprises a control system for controlling the turbomachine during a test and an acquisition system for collecting operating parameters of the turbomachine during the test.

[0006] One of the aims of the present invention is to provide a method for protecting a turbomachine and / or an operator in the event of overspeed of the turbomachine during a test bench test, with a better level of safety.

[0007] To this end, the invention proposes a method for protecting a turbomachine and an operator in the event of overspeed of said turbomachine in a test bench, the protection method comprising the following steps: a. providing an autonomous system for limiting the speed of said turbomachine, said autonomous limitation system being independent of said control system and said acquisition system; b. monitoring the speed of the turbomachine using said autonomous system; c. when said operator is present at the test bench, stopping the turbomachine by the autonomous system when its speed is greater than a first threshold; d. when the speed of the turbomachine is greater than a second threshold greater than said first threshold, stopping the turbomachine by the autonomous system.

[0008] Generally speaking, a human operator's response time to initiate an emergency shutdown is limited. Often, the response time exceeds two seconds, which is high considering the speed at which a turbomachine can go from idle to full speed. For some turbomachines, the time to reach full power from a low-speed state, known as "snap" by those skilled in the art, is around 3 seconds.

[0009] Advantageously, the method according to the invention allows rapid and autonomous intervention, as soon as a critical threshold is exceeded. speed. The first threshold is established primarily for the purpose of protecting the operator. This safety level is designed to intervene before the situation becomes dangerous for individuals present at the test bench. The objective is to prevent injury or physical damage by acting quickly and effectively at the first indication of abnormal acceleration. The second threshold, on the other hand, is focused on the protection of the turbomachine itself. This level is defined to prevent material damage that may result from prolonged operation under abnormal or dangerous conditions. Therefore, the present invention provides a dual-threshold protection system, designed to ensure optimal safety for the operator and the turbomachine during bench tests.Unlike conventional solutions that apply a single cutoff in the event of overspeed regardless of the operator's presence, the dual-threshold approach allows for a progressive response tailored to the severity of the overspeed. The first threshold is set to intervene as soon as an operator is detected in the test area and the turbomachine reaches a critical speed. This level of protection acts preventively, immediately stopping the machine before the situation becomes dangerous for the operator. This approach eliminates the risk of delayed operator reaction and helps prevent accidents in the event of sudden overspeed. The second threshold is set to intervene regardless of the presence of an operator, when the turbomachine's speed exceeds the second threshold. This protection acts as a final barrier to prevent any mechanical or structural damage to the turbomachine.Thanks to this dual-threshold architecture, the invention ensures rapid intervention adapted to different risk levels, while guaranteeing safe operation of the test bench.

[0010] The method according to the invention has other advantages. The method can be easily implemented in existing control and security systems, thus improving security measures without requiring major modifications to the existing infrastructure.

[0011] Therefore, the expression "put on hold" in the context of this document is preferably used, in the sense that the autonomous system of limitation of regime does not act directly on the physical elements of the turbomachine. Instead, the autonomous system sends a signal or command to an existing shutdown control system of the turbomachine. This shutdown control system may be, for example, the Emergency Shutdown System (ESD), which is known to those skilled in the art. Thus, the command from the autonomous system serves as an input for the emergency shutdown system of the turbomachine.

[0012] The use in this document of the verb "to understand", its variants, and its conjugations, cannot in any way exclude the presence of elements other than those mentioned. Similarly, the use in this document of the indefinite article "un", "une", or the definite article "le", "la" or "I'", to introduce an element does not exclude the presence of a plurality of these elements.

[0013] The terms "first", "second", "third", etc. are used in this document exclusively to differentiate between different elements, without implying any order between these elements.

[0014] In one possible embodiment, the first threshold corresponds to a speed value when the turbomachine is in an idle speed. The idle speed, as known to those skilled in the art, refers to the minimum operational state of the turbomachine, where it rotates at the lowest possible speed while remaining active and functional. The choice of this speed as the threshold for automatic shutdown provides increased safety for personnel present near the turbomachine during testing. For example, on a CFM56-5B type turbomachine, this first threshold is preferably between 1000 rpm and 1200 rpm.

[0015] In one possible embodiment, the second threshold corresponds to a speed value when the turbomachine is in a maximum permissible speed. This is intended to establish a final safety barrier before the turbomachine reaches speeds that can lead to catastrophic failures. The maximum permissible speed, as known to those skilled in the art, is defined as the maximum speed at which the turbomachine can operate without suffering irreversible damage. The second threshold is therefore set just below the design limits of the turbomachine. For example, on the CFM56-5B turbomachine, this second threshold is preferably between 5000 rpm and 5200 rpm.

[0016] In one embodiment, the maximum permissible speed comes from a turbomachine manufacturer. Indeed, manufacturers determine this threshold after a series of tests and analyses, taking into account the design characteristics, the materials used, the optimal operating conditions and the safety margins necessary to ensure reliable and safe operation. The advantage of relying on the maximum permissible speed specified by the manufacturer lies in its accuracy and reliability.

[0017] In one embodiment, the shutdown is imposed at step c. in a time interval of less than 10 ms, once the speed of the turbomachine exceeds the first threshold. Advantageously, this allows rapid intervention to effectively prevent human risks associated with overspeed of the turbomachine.

[0018] In one embodiment, the shutdown is imposed in step d. in a time interval of less than 10 ms, once the speed of the turbomachine exceeds the second threshold. Advantageously, this allows a rapid reaction in the event of exceeding a speed even more critical than that considered in step c.

[0019] In one embodiment, the method according to the invention further comprises a step of stopping the turbomachine in the event of a power cut to the autonomous speed limitation system. Indeed, the autonomous speed limitation system is generally powered by electricity, which allows it to monitor the speed of the turbomachine and react to threshold exceedances. However, dependence on electricity also introduces the risk of power cuts which can compromise its functionality. This embodiment then makes it possible to add an additional layer of security to manage cases of electrical failure or other incidents which can affect the normal operation of the autonomous system.

[0020] In one embodiment, the autonomous rev-limiting system comprises a housing with on-board electronics capable of stopping the turbomachine in both cases corresponding to steps c. and d. Advantageously, the housing is compact, integrating all the components necessary to monitor the speed of the turbomachine and execute the shutdown commands. Advantageously, the on-board electronics are designed to operate autonomously, to continuously monitor the speed of the turbomachine and decide whether to shut it down if the predefined thresholds are exceeded.

[0021] The invention further provides an autonomous speed limitation system suitable for use in a test bench for testing a turbomachine and comprising: - a housing comprising: o electronic components for receiving information relating to the speed of a turbomachine; o a non-volatile memory for storing a first and a second threshold of a speed of the turbomachine; o a microcontroller for generating a command to stop the turbomachine based on information relating to a speed of the turbomachine and based on the first and second thresholds; - connection means for sending said command to stop the turbomachine from the housing; the autonomous speed limitation system being independent of any test bench control and acquisition system.

[0022] Advantageously, the autonomous speed limitation system minimizes the risk of accidents, thus protecting equipment and personnel, by acting autonomously to stop the turbomachine when overspeed is detected. In addition, its compact design including a housing, with connection means for sending stop commands, ensures high reliability with minimal maintenance. Furthermore, thanks to the microcontroller, the autonomous system is able to quickly process speed information and generate a stop command in real time. This ability to react instantly when established thresholds are exceeded ensures that actions are taken well before the situation becomes critical. Non-volatile memory, for its part, offers the possibility of storing and modifying these speed thresholds, allowing great flexibility, adapted to the specificities of each turbomachine and the test conditions.

[0023] In a particular embodiment, the connection means comprise electrical cables enabling wiring between the housing and the turbomachine. Advantageously, the electrical cables thus provide a physical and direct connection, which reduces the risks of disturbance or interference which could affect wireless communication means.

[0024] In one possible embodiment, the microcontroller is configured to shut down the turbomachine in the event of a power outage to the housing. Indeed, the housing includes electronic components, such as the microcontroller, non-volatile memory, and other circuits necessary for data processing, speed threshold detection, and shutdown command generation. These components require a source of electrical power to operate properly. However, under certain circumstances, the power supply may be unstable and subject to interruptions. In this embodiment, the fact that the microcontroller is configured to shut down the turbomachine in the event of a power outage to the housing adds an additional layer of safety to the autonomous speed limitation system.This feature ensures that, even in the event that the system itself is compromised by a loss of power, the turbomachine is automatically shut down to prevent any potential risk.

[0025] The inventors also propose a protection system for implementing a method according to any of the aforementioned embodiments, and comprising: • a first sensor to detect the presence of the operator in a given area; • a second sensor to measure the speed of the turbomachine; an autonomous rev limiting system according to any one of the three aforementioned embodiments. Brief description of the figures

[0026] Other characteristics and advantages of the present invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended figures, among which: - figure 1 illustrates a schematic representation of the steps of the method according to the invention; - figure 2 illustrates a schematic representation of a system for implementing the method according to the invention; - Figure 3 illustrates a view of an operator present in a given area of ​​the test bench.

[0027] The drawings of the figures are not to scale. Like elements are generally denoted by like references in the figures. For the purposes of this document, identical or similar elements may bear the same references. Furthermore, the presence of reference numbers or letters in the drawings cannot be considered as limiting, including when these numbers or letters are indicated in the claims. Detailed Description of Certain Embodiments of the Invention

[0028] This section presents a detailed description of certain embodiments of the present invention. The latter is described with particular embodiments and references to figures but the invention is not limited by them. In particular, the drawings and figures described below are only schematic and are not limiting.

[0029] Figure 1 illustrates a schematic representation of the steps of the method for protecting a turbomachine and an operator in the event of overspeed of the turbomachine in a test bench. The test bench comprises a control system for controlling the turbomachine during a test and an acquisition system for collecting operating parameters of the turbomachine during the test. The method according to the invention comprises a step a. consisting of providing a system autonomous turbomachine speed limitation system. The autonomous limitation system is independent of the control system and the turbomachine acquisition system. A step b. of the method consists of monitoring the turbomachine speed using the autonomous system. A step c. of the method consists of, when the operator is present at the test bench, stopping the turbomachine using the autonomous system when its speed is greater than a first threshold. A step d. of the method consists of, when the turbomachine speed is greater than a second threshold greater than the first threshold, stopping the turbomachine using the autonomous system. Preferably, the first threshold corresponds to a speed value when the turbomachine is in an idle speed. Preferably, the second threshold corresponds to a speed value when the turbomachine is in a maximum admissible speed.The maximum permissible speed preferably comes from a turbomachine manufacturer. For example, on a CFM56-5B type turbomachine, the first threshold is preferably set at 1150 rpm (Ground Idle) and the second threshold is preferably set at 5100 rpm. Preferably, the protection method according to the invention further comprises a step (not shown) of stopping the turbomachine in the event of a power cut to the autonomous speed limitation system.

[0030] Figure 2 illustrates a schematic representation of a protection system 40 intended for implementing the method according to the invention. As illustrated in Figure 2, the autonomous speed limitation system 5 comprises a housing 3. The housing 3 provides optimal protection against dust and humidity, thus ensuring the optimal operation of the electronic components it houses.

[0031] The housing 3 comprises electronic components 16 designed to receive information relating to the speed of a turbomachine. They preferably include amplifiers and signal conditioners. The latter ensure the adjustment and filtering of the incoming signals so that their amplitude and format are adapted to the processing. This is ensured by a microcontroller 11 which is capable of generating a command to stop the turbomachine, in based on received speed data and predefined thresholds stored in non-volatile memory 10.

[0032] The non-volatile memory 10 may, for example, take the form of an EEPROM (Electrically-erasable programmable read-only memory). This makes it possible to retain data, such as the speed thresholds for stopping the turbomachine, even in the event of a power outage. Thanks to its ability to be electrically reprogrammed, the memory 10 allows the thresholds to be updated as needed, without requiring the autonomous speed limitation system 5 to be completely replaced.

[0033] Preferably, the microcontroller 11 does not directly intervene on the physical components of the turbomachine. The microcontroller 11 preferably transmits a signal or command to an existing shutdown control system of the turbomachine, such as the Emergency Shutdown System (ESD), well known to those skilled in the art. The command from the microcontroller 11 then serves as an input to the emergency shutdown system of the turbomachine, adding an additional layer of safety without requiring major modifications to the main control system of the turbomachine.

[0034] The microcontroller 11 may, for example, be an AVR microcontroller from Atmel, programmed to analyze the input signals, compare this data to the thresholds stored in the memory 10, and generate shutdown commands if necessary.

[0035] Preferably, the microcontroller 11, the non-volatile memory 10 and the electronic components dedicated to receiving the speed information are integrated on a printed circuit board (PCB). This integration aims to create a compact, robust and easy-to-install system.

[0036] The housing 3 is generally powered by a standard electricity source of the installation. Preferably, the microcontroller 11 is configured to initiate a shutdown of the turbomachine in the event of a power failure of the housing 3, thus adding additional protection. This functionality is possible, for example, thanks to a power failure detector circuit, designed to deactivate the microcontroller 11 immediately when the supply voltage falls below a critical threshold, without the need to use a battery-type backup device. By construction, if the microcontroller is deactivated, the protection is still active (safety logic).

[0037] The connection between the housing 3 and the turbomachine is established by means of connection means 9 for sending the command to stop the turbomachine from the housing 3. These connection means 9 are preferably in the form of electrical cables for direct wiring. This ensures efficient and immediate transmission of the stop commands.

[0038] Finally, the protection system 40 also includes a first 12 and a second 13 sensors. The first sensor 12 has the role of detecting the presence of the operator in a given area of ​​the test bench. This sensor 12 may be, for example, a TOR sensor at the access door to the test bench. The sensor activates a signal which is sent to the autonomous speed limitation system 5. A TOR or All Or Nothing sensor is known to a person skilled in the art.

[0039] The second sensor 13, meanwhile, is responsible for measuring the speed of the turbomachine. An example of a sensor 13 is the Hall effect sensor, used for precise and real-time measurement of the rotational speed of the turbomachine, or the original sensor installed on the turbomachine.

[0040] These sensors, through their functionality and their integration into the autonomous rev limitation system 5, make it possible to provide essential data to the microcontroller 11 for rapid and efficient decision-making, thus guaranteeing optimal safety at the test bench level.

[0041] Figure 3 illustrates a view of an operator 22 present in a given area of ​​the test bench 7. In the test bench 7, there is preferably a central area where a turbomachine 15 is tested equipped with various instruments to test its performance, the test bench 7 is provided, for example, with side walkways. These walkways, designed for safety and accessibility, allow an operator to closely monitor the test operations while moving easily along the test bench 7. They are equipped, for example, with guards body to prevent accidental falls and ensure operator safety during testing.

[0042] The operator 22 is, for example, shown standing on one of these walkways. The first sensor 12 is, for example, mounted on the access door of the test bench. The first sensor 12 detects the presence of the operator 22 in the designated area, and sends a signal to the autonomous speed limitation system 5 which stops the turbomachine 15 when its speed exceeds the first threshold. This, preferably, corresponds to a speed value when the turbomachine 15 is in an idle speed.

[0043] In summary, the invention relates to a method for protecting a turbomachine 15 and / or an operator 22 in the event of overspeed of a turbomachine 15 in a test bench 7. The invention makes it possible to reinforce the level of safety and guarantee autonomous and rapid intervention, to protect both personnel and equipment.

[0044] The present invention has been described above in relation to specific embodiments, which are of purely illustrative value and should not be considered as limiting. It will be readily apparent to those skilled in the art that the invention is not limited to the examples illustrated or described above, and that its scope is more broadly defined by the claims introduced below.

Claims

Claims 1. Method for protecting an aircraft turbomachine (15) and / or an operator (22) in the event of overspeed of said turbomachine (15) in a test bench (7), said test bench (7) comprising a control system for controlling the turbomachine (15) during a test and an acquisition system for collecting operating parameters of the turbomachine during said test, the protection method comprising the following steps: a. providing an autonomous system (5) for limiting the speed of said turbomachine (15), said autonomous limitation system (5) being independent of said control system and said acquisition system; b. monitoring the speed of the turbomachine using said autonomous system (5); c. when said operator (22) is present at the test bench (7), stopping the turbomachine (15) by the autonomous system (5) when its speed is greater than a first threshold; d.when the speed of the turbomachine (15) is greater than a second threshold greater than said first threshold, stopping the turbomachine (15) by the autonomous system (5).

2. Method according to claim 1, characterized in that said first threshold corresponds to a speed value when the turbomachine (15) is in an idle speed.

3. Method according to any one of the preceding claims, characterized in that said second threshold corresponds to a speed value when the turbomachine (15) is in a maximum admissible speed.

4. Method according to the preceding claim, characterized in that the maximum admissible speed comes from a manufacturer of the turbomachine (15).

5. Method according to any one of the preceding claims, characterized in that the stop is imposed in step c. in a time interval of less than 10 ms, once the speed of the turbomachine (15) is greater than the first threshold.

6. Method according to any one of the preceding claims, characterized in that the stop is imposed in step d. in a time interval of less than 10 ms, once the speed of the turbomachine (15) is greater than the second threshold.

7. Method according to any one of the preceding claims, further comprising a step of stopping the turbomachine (15) in the event of a power cut in said autonomous speed limitation system (5).

8. Method according to any one of the preceding claims, characterized in that the autonomous speed limitation system comprises a housing (3) with on-board electronics capable of stopping the turbomachine (15) in the two cases corresponding to steps c. and d.

9. Autonomous system (5) for limiting speed suitable for use in a test bench (7) for testing a turbomachine (15) and comprising: - a housing (3) comprising: o electronic components (16) for receiving information relating to the speed of a turbomachine (15); o a non-volatile memory (10) for storing a first and a second threshold of a speed of the turbomachine (15); o a microcontroller (11) for generating a command to stop the turbomachine (15) on the basis of information relating to a speed of the turbomachine (15) and based on the first and second thresholds; - connection means (9) for sending said command to stop the turbomachine (15) from the housing (3); said autonomous speed limitation system (5) being independent of any control and acquisition system of the test bench (7).

10. Autonomous system (5) for limiting the speed according to the preceding claim, characterized in that the connection means (9) comprise electrical cables allowing wiring between the housing (3) and the turbomachine (15).

11. Autonomous system (5) for limiting the speed according to any one of the two preceding claims, characterized in that the microcontroller (11) is configured to stop the turbomachine (15) in the event of a power cut to said housing (3).

12. Protection system (40) for implementing a method according to any one of claims 1 to 8 and comprising: • a first (12) sensor to detect the presence of the operator in a given area; • a second (13) sensor to measure the speed of the turbomachine; • an autonomous system (5) for limiting the speed according to any one of the three preceding claims.

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