FR3127286A1 - Triggering by laser of an electrical or electronic device located in the rotating part of a rotating machine - Google Patents

Abstract

The invention relates to a system for triggering the operation of an electrical or electronic device integrated in the rotating part of a rotating machine, the system comprising: - a laser source, for emitting a laser beam of a determined wavelength ; - an optoelectronic detector, integrated in the rotating part, to receive an optical signal transmitted by the laser beam, convert this optical signal into an electrical signal, and transmit the electrical signal to the device, so as to trigger the operation of the device. The optoelectronic detector comprises: - an optical fiber, for guiding light beams towards a selective optical sensor, a first end of the optical fiber being arranged on the surface of the rotating part and a second end being connected to the selective optical sensor, the first end and the laser source being oriented with respect to each other such that during one full rotation of the rotating part the laser beam penetrates the first end at least once; - the selective optical sensor, configured to receive optical signals, select the optical signal of determined wavelength from among the optical signals received, convert the optical signal of determined wavelength into an electrical signal capable of triggering the operation of the device and transmitting the electrical signal to the device. Figure for abstract: none

Description

Triggering by laser of an electrical or electronic device located in the rotating part of a rotating machine

The field of the invention is that of the rotational tests of rotating machines requiring the triggering of a device by electrical impulse.

The invention can for example be applied to the case where the device is a detonator of an explosive charge, used in FBO tests.

PRIOR ART

There are many rotational tests that require the triggering of a device by electrical impulse. As a reminder, rotational tests are tests carried out on a rotating machine, a rotating machine which can be, for example, a turbojet, a gas turbine, a hydraulic turbine, etc.

The most representative type of rotational test consists of simulating the failure of a turbojet fan blade when it is at full power. To do this, an explosive charge is placed at the foot of a fan blade and, by means of a rotating transformer which is integrated in the turbojet engine, which receives a strong electrical impulse and which transmits it to a detonator connected to the explosive charge, the explosive charge breaks the foot of the dawn. This type of firing device (rotating transformer + detonator) is used in particular for so-called FBO tests (for “Fan Blade Out”).

For FBO tests, the rotating transformer of the current firing device is integrated into the element under test. By way of example, if the element under test is a turbojet equipped with a motor and a fan, the transformer is cut into two modules, the stator (primary), which is fixed to the body of the motor, and the (secondary) rotor, which is attached to the fan shaft.

For the firing process with the current device ( ), a firing system 1 makes it possible to send a high-current pulse into the fixed primary 3 of the rotating transformer 2; the rotating secondary 4 of the rotating transformer recovers the result of the pulse and sends it directly to the detonator 5 connected to the explosive charge. Reference 6 represents the rotating shaft of the rotating machine.

The current firing device has the advantage of having a very simple operating principle, but it also has many disadvantages.

The efficiency of the rotary transformer is very low. Thus, to trigger the detonator, it is necessary to inject a strong current into the primary of the rotating transformer, which has the effect of disturbing the measurements of the element under test (for example, the turbojet, in the case of tests failure of a fan blade).

In addition, the manufacture of the rotating transformer is delicate and there are disparities in yields from one transformer to another.

The integration of the rotating transformer on the element under test has an impact on the configuration of the element under test.

In addition, the rotary transformer must be adapted to each element under test. For example, in the case of a turbojet, the rotating transformer must be adapted to each engine under test and in the event of a fault in this one, its undocking of the low pressure compressor (booster) is very time consuming.

Furthermore, it is necessary to set up electrical conductor cables of great length and of large section in the test bench in order to connect the firing system and the firing device.

The known impacts of the current firing system (firing system + firing device) in the event of problems are numerous.

For example, in the case of damaged electrical conductors, the search for the damaged conductor takes time and the difficulty of access to the element under test must also be taken into account.

It is also necessary to take into account the electromagnetic disturbances due to the environment of the element under test or the test bench, which are likely to cause an accidental triggering of the explosive charge.

It is also necessary to take into account the fact that there is a delay between the firing order and the activation of the explosive charge due to the inductances and capacitances of the cables and the rotating transformer.

The object of the invention is to limit, or even eliminate, the drawbacks mentioned above in order to propose a system for triggering a device integrated in the rotating part of a rotating machine, which is safer than those of the prior art. .

To do this, the subject of the invention is a system for triggering the operation of an electrical or electronic device integrated in the rotating part of a rotating machine, the system comprising:
- a laser source configured to emit a laser beam of a determined wavelength;
- an optoelectronic detector, integrated in the rotating part, configured to receive an optical signal transmitted by the laser beam, convert the optical signal into an electrical signal, and transmit the electrical signal to the electrical or electronic device, so as to trigger the operation of said device ;
wherein the optoelectronic detector comprises:
- an optical fiber configured to guide light beams, including the laser beam coming from the laser source, towards a selective optical sensor, a first end of the optical fiber being arranged on the surface of the rotating part and a second end being connected to the selective optical sensor, the first end and the laser source being oriented with respect to each other so that, during a complete rotation (i.e. 360°) of the rotating part, the laser beam of determined wavelength emitted by the laser source penetrates at least once into the first end;
- the selective optical sensor, configured to receive optical signals, select the optical signal of determined wavelength from among the optical signals received, convert the optical signal of determined wavelength into an electrical signal able to trigger the operation of the device and transmitting the electrical signal to the device.

As a reminder, a rotating machine comprises a rotating part and a fixed part; the two parts are generally coaxial and the rotating part rotates along this axis.

The laser source can emit UV or IR beams.

According to a variant, the selective optical sensor comprises:
- a detection cell, configured to convert an optical signal into an electrical signal and transmit the electrical signal to the device;
- a filtration system of order greater than or equal to 2, arranged between the second end of the optical fiber and the detection cell, forming a band-pass filter capable of stopping the light beams other than the laser beam with a length of determined wave coming out of the optical fiber and transmitting the laser beam to the cell.

These light beams (or optical beams) other than the laser beam of determined wavelength can be stray light beams for the cinematography of the test.

Advantageously, the filtration system is obtained by combining at least one low-pass filter of order 2 or higher and at least one high-pass filter of order 2 or higher, the sum of the orders of the filters being greater than 2.

According to a variant of the invention, the electrical or electronic device is a detonator connected to an explosive charge. The triggering of the operation is therefore here the triggering of the firing of the detonator.

The invention also relates to a method for using a system as defined above, the method comprising a phase of triggering the operation of the electrical or electronic device, the triggering phase comprising the steps of:
- emission, by the laser source, of a laser beam of determined wavelength on the rotating part of the rotating rotating machine, during at least one complete rotation of the rotating part, so that the first end of the optical fiber can capture the laser beam at least once;
- Reception, by the optoelectronic detector, of the laser beam of determined wavelength and of light beams other than the laser beam of determined wavelength;
- selection, among the light beams received, of the laser beam of determined wavelength;
- conversion of the selected optical signal into an electrical signal;
- transmission of the electrical signal to the electrical or electronic device.

Advantageously, the method further comprises, before the triggering phase, a phase of adequate positioning of the laser source which comprises:
- the emission, on the rotating rotating part, of a laser beam of determined wavelength and displacement of the laser source until the reception, by the optoelectronic detector, of the optical signal transmitted by the laser beam;
- the conversion of the optical signal into an electrical signal;
- the transmission of the electrical signal to a control device integrated in the rotating part and provided with an indicator light which is arranged on the surface of the rotating part of the rotating machine;
- Lighting of the indicator light, so as to indicate to a user that the laser source is correctly positioned.

Advantageously, the method further comprises, before the triggering phase and after the possible phase of adequate positioning of the laser source, a phase for securing the device preventing its operation which comprises:
- A de-energization of the optoelectronic sensor, so as to prevent transmission of an electrical signal to the device; And
- When the device can be used, a tensioning of the optoelectronic sensor, so as to make possible a transmission of an electrical signal to the device.

This safety phase is particularly useful when the device is a detonator. It prevents accidental firing of the detonator.

The system and the method according to the invention make it possible to eliminate the risks of damage to the electrical conductors routed in the rotating machines under test.

They make it possible to reduce modifications to the configuration of the rotating machine. For example, for the blade retention test, removing the rotating transformer allows the energy needed to trigger the explosive charge to be routed.

They make it possible to use a method which does not use position sensors to give the angular position of the rotating part of the rotating machine. For example, in the case of a blade retention test, position sensors are not used to give the position of the fan in order to trigger the explosive charge at the desired moment. This is advantageous because often, for this type of test in the prior art, the sensors were not equipped with a sufficient number of outputs and it was necessary to install additional measurement lines on the rotating machine.

They also make it possible to suppress electromagnetic disturbances on the measurements to be recorded during a rotating test when the explosive charge is triggered; indeed, in the prior art, disturbances are generated by the high current pulse which passes through the electrical conductors allowing the ignition of the explosive charge.

The system according to the invention also has numerous advantages.

The optoelectronic detector of the system according to the invention has very little impact on the definition of the rotating part under test, because it is light and is contained in the rotating part of the rotating machine, for example in the cone of the fan. a turbojet engine.

Its installation, dismantling and replacement are quick.

An investigation in case of malfunction of the optoelectronic detector is facilitated. For example, in the case of a turbojet fan, this investigation only requires disassembly of the fan cone to be able to access the optoelectronic detector.

The optoelectronic detector has no impact on the quality of the measurements made on the rotating part under test.

The adjustment of the trigger angle of the device is facilitated, because it is done by simply changing the position of the laser beam on the cone of the fan; there is no need to use a position sensor integrated in the rotating part under test (for example, a sensor of the top turn type).

Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of a preferred embodiment thereof, given by way of non-limiting example, and made with reference to the attached drawings on which:

- , already described, represents a schematic view of a current firing device using a rotary transformer;

- represents, according to a schematic sectional view, the system according to the invention;

- shows, in a sectional view, the detail of various elements of the system according to the invention which are located in the rotating part of a rotating machine;

- represents, according to a front view, a turbojet fan and makes it possible to see the trace of the flat laser beam on the cone of the fan.

DETAILED DISCUSSION OF PARTICULAR EMBODIMENTS

The system and the method according to the invention can be adapted to all rotating machines requiring the triggering with angular precision of an electrical or electronic device integrated in the rotating part of the rotating machine, for example for recording of a measure. Indeed, the optoelectronic detector of the system according to the invention can be integrated into the rotating part of any rotating machine to trigger all kinds of electrical devices, such as for example a detonator connected to an explosive charge in the case of an FBO test.

The system and the method described above can in particular be used to carry out all rupture tests of a part by explosive charge on a rotating part of a rotating machine, where a precise angular position of the rotating part is required.

To illustrate the invention, we will precisely describe the laser triggering of a pyrotechnic charge during a blade retention test on a turbojet engine.

During such a test, the aim is to trigger an explosive charge when the turbojet engine is at full power, in order to cut off a turbojet fan blade at its base. The blade must be cut in a precise angular position of the fan.

In the is illustrated a laser beam 7, coming from a laser source 8, arriving on the cone 9 of a fan 17 of a turbojet engine.

In the is illustrated the detail of the interior of the cone 9. It can be seen that it contains an optoelectronic detector, comprising here an optical fiber 10 whose one end 11 (symbolized by a circle), which is flush with the surface of the cone 9, will be able to capture the laser beam 7, as well as an optical sensor 12. The optical sensor 12 is electrically connected to the device to be triggered 13 (detonator), which here is a detonator which is arranged at the base of a blade 16. In this representation , there is also an indicator light 14, which is arranged on the surface of the cone 9.

The triggering of the explosive charge by the detonator 13 is activated by a laser beam 7 aiming at a small optoelectronic detector which is integrated in the cone of the fan of the turbojet engine. Advantageously, the laser beam is aimed at an end 11 of an optical fiber 10, connected to an optical sensor 12, the end 11 being placed on the surface of the rotating part of the rotating machine (for example, the optical fiber passes through the wall of the fan cone so that the end is flush with the surface level of the cone).

The method according to the invention allows the following:
- the position of the optoelectronic detector (or, advantageously, of the end of the optical fiber of the optoelectronic detector) on the rotating part of the specimen under test;
- the position of the laser beam aimed at an area containing the optoelectronic detector; And
- the point of intersection of the optoelectronic detector (and preferably, of the end of the optical fiber of the optoelectronic detector) and the laser beam;
to be able to trigger the explosive charge in a precise angular position of the fan.

During an FBO test, when a laser beam illuminates an area of the rotating part of the rotating machine, the optical fiber, one end of which is located on the surface of the cone of the fan, will cross the laser beam during the rotation of the rotating part; the laser light will therefore be transmitted to the selective laser sensor located in the cone, and the sensor 12 will transmit an electrical signal to the detonator 13, which triggers the firing of the detonator.

Before the FBO test, the position of the laser beam on the cone of the fan can be adjusted under the same conditions as the FBO test. This adjustment is to be made dynamically, because the position of the engine can vary due to the thrust balance of the bench, its thrust or other.

Preferably, one or more diffraction lenses arranged in front of the laser source 8 are used in order to generate a flat laser beam 7; thus, when it reaches the rotating part, the meeting of the laser beam with the surface of the rotating part forms a line. This laser line can be located between the axis of rotation of the rotating part and its periphery. Thus, during a complete rotation of the rotating part, it is easier for the laser beam to intercept the end of the optical fiber when it is in the form of a flat laser beam than when it is under the shape of a point.

In the , the trace 15 of the flat laser beam 7 is represented on the cone. You can also see the circles which respectively represent the end 11 of the optical fiber and the indicator light 14.

To adjust the position of the laser beam, the laser source can, for example, be equipped with a motor controlled in XYZ.

As a safety precaution, the optoelectronic detector can be switched off outside of the actual FBO test. The transmission of an electrical signal between the optoelectronic detector and the device to be triggered is then not possible. Once the position of the laser beam is adjusted, the cone is removed in order to power up the optoelectronic detector, then the cone is put back in place.

According to another safety measure, it is also possible, before starting the engine of the turbojet or during the idling phase, to send an order to the optoelectronic sensor, for example via an HF link, in order to authorize the future triggering of the device. A return is then obtained, for example by an indicator light 14 visible on the cone of the fan via cameras or else by a return HF link, indicating that the device is ready to be triggered. This is particularly useful when the device to be triggered is a detonator of an explosive charge and it is desired to check whether the detonator is ready to be triggered (for example, when it has been verified that no one is located in the area near the explosive charge). Then, the motor is put under the expected test conditions. And finally, a pulse of the laser beam is triggered on the cone; preferably, the pulse time is equivalent to one revolution of the fan.

Claims (7)

System for triggering the operation of an electric or electronic device (13) integrated in the rotating part (9) of a rotating machine (2), the system comprising:
- a laser source (8) configured to emit a laser beam (7) of a determined wavelength;
- an optoelectronic detector, integrated in the rotating part, configured to receive an optical signal transmitted by the laser beam (7), to convert the optical signal into an electrical signal, and to transmit the electrical signal to the electrical or electronic device, so as to trigger the operation of said device (13);
wherein the optoelectronic detector comprises:
- an optical fiber (10) configured to guide light beams, including the laser beam (7) coming from the laser source, towards a selective optical sensor (12), a first end (11) of the optical fiber being arranged at the surface of the rotating part and a second end being connected to the selective optical sensor, the first end and the laser source being oriented with respect to each other so that, during a complete rotation of the rotating part, the laser beam (7) of determined wavelength emitted by the laser source penetrates at least once into the first end (11);
- the selective optical sensor, configured to receive optical signals, select the optical signal of determined wavelength from among the optical signals received, convert the optical signal of determined wavelength into an electrical signal able to trigger the operation of the device and transmitting the electrical signal to the device. A system according to claim 1, wherein the selective optical sensor comprises:
- a detection cell, configured to convert an optical signal into an electrical signal and transmit the electrical signal to the device;
- a filtration system of order greater than or equal to 2, arranged between the second end of the optical fiber and the detection cell, forming a band-pass filter able to stop light beams other than the laser beam with a length of determined wave coming out of the optical fiber and transmitting the laser beam to the cell. Device according to Claim 2, in which the filtration system is obtained by associating at least one low-pass filter of order 2 or higher and at least one high-pass filter of order 2 or higher, the sum of the orders of the filters being greater than 2. A system according to any of claims 1 to 3, wherein the device is a detonator connected to an explosive charge. Method of using a system according to any one of claims 1 to 4, the method comprising a phase of triggering the operation of the electrical or electronic device, the triggering phase comprising the steps of:
- emission, by the laser source, of a laser beam of determined wavelength on the rotating part of the rotating rotating machine, for at least one complete rotation of the rotating part, so that the first end of the optical fiber can capture the laser beam at least once;
- reception, by the optoelectronic detector, of the laser beam of determined wavelength and of light beams other than the laser beam of determined wavelength;
- selection, among the light beams received, of the laser beam of determined wavelength;
- conversion of the selected optical signal into an electrical signal;
- transmission of the electrical signal to the electrical or electronic device. Method according to claim 5, further comprising, before the triggering phase, a phase of adequate positioning of the laser source which comprises:
- the emission, on the rotating rotating part, of a laser beam of determined wavelength and displacement of the laser source until the reception, by the optoelectronic detector, of the optical signal transmitted by the laser beam;
- the conversion of the optical signal into an electrical signal;
- transmission of the electrical signal to a control device integrated in the rotating part and provided with an indicator light (14) which is arranged on the surface of the rotating part of the rotating machine;
- the lighting of the indicator light, so as to indicate to a user that the laser source is correctly positioned. Method according to claim 5 or claim 6, further comprising, before the triggering phase and after any phase of adequate positioning of the laser source, a phase of securing the device preventing its operation which comprises:
- de-energization of the optoelectronic sensor, so as to prevent transmission of an electrical signal to the device; And
- when the device can be used, energizing the optoelectronic sensor, so as to make it possible to transmit an electrical signal to the device.