Drive turbine and its protection method

Abstract

A drive turbine (1) comprising an inlet (2) configured to admit a drive fluid, and a pyrotechnic opening device (5) configured, in a standby state, to allow the drive fluid to enter the inlet (2), and in a safe state, to pyrotechnically trigger the opening of at least one drive fluid discharge outlet leading out of the inlet (2). Abstract figure: Figure 1

Description

Title of the invention: Drive turbine and method of protecting it Technical field

[0001] The present invention relates to the field of drive turbines.

[0002] In a known manner, a drive turbine, in particular a steam or compressed air turbine, comprises an alternation of rotor discs and stator discs provided with blades and surrounded by a casing. The circulation of a fluid in the turbine makes it possible to drive the rotor discs in rotation, and consequently a rotating shaft on which the rotor discs are secured.

[0003] It is known to use drive turbines in test facilities for testing the aerodynamic and acoustic performance of rotating machines, such as a fan or a compressor intended to be mounted in an aircraft. The test rotating machine is driven in rotation by coupling with the rotating shaft of the turbine.

[0004] In practice, in the event of a break in the rotating shaft of the turbine, the turbine is likely to quickly enter an overspeed regime. Such an overspeed regime is undesirable because it can lead to accelerated wear of the turbine or even damage, and in certain cases a risk of projections into the environment of the test installation. Such a risk can also appear in the presence of an unbalance on the rotating test machine, caused for example by the loss of a blade.

[0005] Patent application US2016 / 0251977A1 ​​discloses an aircraft turbomachine in which a braking assembly is mounted on the rotating shaft secured to the turbine. In overspeed conditions, the braking assembly, which may be hydraulic, mechanical or magnetic, makes it possible to apply a resistive torque to the rotating shaft and thus reduce the turbine speed. However, such a braking assembly does not make it possible to avoid the occurrence of overspeeds.

[0006] It is also known from patent application EP2990628A1 to add a valve upstream of the burner of a gas turbine in order to close the fuel supply when an unbalance is measured to reduce the rotational speed of the shaft. However, the valves have the disadvantage of having a long reaction time, in particular in the presence of high feed rates as is the case in steam or compressed air turbines. This does not allow the turbines to be effectively protected from overspeeds.

[0007] The invention thus aims at rapid protection of drive turbines, in particular steam or compressed air turbines, in the event of an event which could lead to a overspeed. PRESENTATION OF THE INVENTION

[0008] A drive turbine comprising an inlet configured to admit a drive fluid is disclosed.

[0009] The invention is remarkable in that it comprises a pyrotechnic opening device configured: • in a waiting state, to allow the admission of the drive fluid into the inlet, and • in a safety state, to pyrotechnically trigger the opening of at least one drive fluid discharge outlet opening out of the inlet.

[0010] The opening device is said to be pyrotechnic in that it comprises controlled explosive actuation means, having a very short response time, in practice of the order of one millisecond. Preferably, the explosive actuation means are controlled electrically, in particular, following detection by a sensor. This advantageously makes it possible to discharge substantially immediately at least a portion of the drive fluid from the inlet of the drive turbine when it is likely to enter an overspeed regime. The early opening of the discharge outlet advantageously makes it possible to quickly reduce the pressure of the drive fluid supplying the drive turbine and consequently to effectively reduce the drive of the rotary shaft, so as to prevent it from reaching an overspeed regime.The integrity of the drive turbine is advantageously preserved by avoiding its accelerated wear and / or deterioration. In addition, the test is made safe by avoiding a risk of projections into the environment of the test installation.

[0011] According to one aspect of the invention, the pyrotechnic opening device is in the form of a valve comprising at least one flap closing the discharge outlet and configured to be opened by pyrotechnic actuation. The very short response time of such a valve makes it possible to redirect almost immediately at least part of the drive fluid out of the inlet, in a simple and practical manner.

[0012] According to one aspect of the invention, in the safety state, the pyrotechnic opening device prevents the admission of the drive fluid into the inlet. The admission of the drive fluid is advantageously stopped almost immediately without the occurrence of a water hammer, thanks to the redirection of the fluid into the discharge outlet. This is particularly advantageous in the presence of high fluid flow rates, as is the case in steam or compressed air turbines. used on test bench.

[0013] According to one aspect of the invention, the drive turbine comprises: • a rotating shaft and a braking device controllable between an active state, in which it applies a resistive torque to the rotating shaft, and an inactive state, • a cooling pipe into which the discharge outlet opens and configured to guide the drive fluid into contact with the braking device.

[0014] The braking device advantageously allows, in addition to the pyrotechnic valve, rapid safety of the turbine. The cooling pipe allows for cooling by thermal convection of the braking device by cleverly reusing the redirected drive fluid, thus avoiding overheating of the braking device which has to dissipate a very large amount of kinetic energy. This allows for space savings and reduces energy costs.

[0015] According to one aspect of the invention, the braking device is of the magnetic type, preferably eddy current. Such a device has a large heat exchange surface, which facilitates its cooling.

[0016] According to one aspect of the invention, the drive turbine comprises a first discharge outlet opening into the cooling pipe and a second discharge outlet opening out of the drive turbine, the pyrotechnic opening device being configured, in the safety state, to prohibit the admission of the drive fluid into the first discharge outlet if the temperature of the drive fluid is higher than a predetermined threshold. This makes it possible to use the fluid for cooling purposes only if it has a temperature lower than a predetermined threshold. The fluid is otherwise discharged to the outside in a simple and practical manner.

[0017] According to one aspect of the invention, the pyrotechnic valve is mounted adjacent to the inlet of the drive turbine. Closing the valve thus allows immediate cut-off of the fluid supply to the turbine, and therefore early safety.

[0018] According to one aspect of the invention, the drive turbine is of the steam or compressed air type. The pyrotechnic opening device is particularly suitable for such turbines having a high compressed air or steam supply flow rate, allowing very rapid shutoff without risk of water hammer, unlike other types of valves.

[0019] The invention also relates to a test bench comprising a drive turbine as described above. Thanks to the invention, the test bench can be quickly secured in the event of blade loss or breakage of the rotating shaft during testing.

[0020] The invention also relates to a method for protecting a drive turbine as described above, in which the pyrotechnic opening device is initially in the standby state, the method comprising a step of pyrotechnic triggering of the safety state of the pyrotechnic opening device following detection of a risk of overspeed of the drive turbine. In particular, the safety state is triggered if the rotation speed of the drive turbine exceeds a predetermined threshold speed.

[0021] According to a preferred aspect of the invention, the braking device being initially in the inactive state, the method comprises a step of controlling the active state of the braking device following the detection of the risk of overspeed of the drive turbine.

[0022] According to a preferred aspect of the invention, the redirection valve being initially in the second state, the method comprises a step of controlling the first state of the redirection valve so as to cool the braking device in the active state.

[0023] According to a preferred aspect of the invention, the pyrotechnic triggering step consists of pyrotechnically triggering the opening of the first discharge outlet opening into the cooling pipe if the temperature of the drive fluid is higher than a predetermined threshold. The drive fluid is advantageously reused to cool the braking device, to reduce the overall energy cost.

[0024] According to a preferred aspect of the invention, the pyrotechnic triggering step consists of pyrotechnically triggering the opening of the second discharge outlet leading out of the drive turbine if the temperature of the drive fluid is below a predetermined threshold. The drive fluid is advantageously reused for cooling if its temperature allows sufficient heat exchanges and is discharged to the outside otherwise. PRESENTATION OF THE FIGURES

[0025] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0026] [Fig.l] is a schematic representation of a drive turbine according to one embodiment of the invention.

[0027] [Fig.2] is a schematic representation of a drive turbine according to another embodiment of the invention outside of an event likely to cause overspeed.

[0028] [Fig.3] and [Fig.4] are schematic representations of the turbine [Fig.2] training during an event likely to cause overspeed.

[0029] [Fig.5] is a schematic representation of a method for protecting the drive turbine of [Fig.1] according to an embodiment of the invention.

[0030] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0031] With reference to [Fig. 1], the invention relates to a drive turbine 1 conventionally comprising an alternation of rotor discs 3 and stator discs provided with blades and surrounded by a casing. The drive turbine 1 conventionally comprises a rotary shaft 4 on which the rotor discs 3 are secured as well as an inlet 2 configured to admit a drive fluid F ([Fig. 2]). In this example, the drive turbine 1 is supplied by a supply pipe 15 opening into the inlet 2. The circulation of the drive fluid F in the turbine 1 makes it possible to drive the rotor discs 3 in rotation, and consequently the rotary shaft 4. The drive turbine 1 thus makes it possible to drive in rotation one or more loads 20 which are mechanically coupled to the rotary shaft 4.

[0032] According to one aspect of the invention, the drive turbine 1 is mounted on a test bench. The load 20 is in the form of a rotating test machine, such as a blower in the example of [Fig.l], or a compressor, the aerodynamic and acoustic performance of which, for example, it is desired to verify. The drive turbine 1 is preferably in the form of a steam turbine or a compressed air turbine. Such a turbine thus only discharges air or water, which makes its installation simple and practical in a test installation.

[0033] Still with reference to [Fig.l], according to the invention, the drive turbine 1 comprises a pyrotechnic opening device 5 configured: • in a waiting state O illustrated in [Fig.2], to allow the admission of the drive fluid F into the inlet 2 of the turbine 1, and • in a safety state D illustrated in figures 3 and 4, to pyrotechnically trigger the opening of at least one discharge outlet 11, 12 of the drive fluid F emerging from the inlet 2 of the turbine 1.

[0034] The opening device 5 is said to be pyrotechnic in that it comprises controlled explosive actuation means, having a very short response time, in practice of the order of one millisecond. Preferably, the explosive actuation means are controlled electrically, in particular from a sensor of a parameter of the drive turbine 1, for example, a speed sensor 9. In this example, a control member 8, such as a computer, makes it possible to collect the measurements from the sensors and to control the pyrotechnic opening device 5. The pyrotechnic opening device 5 has a fuse function and is preferably single-use.

[0035] The pyrotechnic opening device 5 is mounted in the supply line 15 and advantageously makes it possible to redirect, with a very short response time, at least a portion of the drive fluid F out of the inlet 2 when the drive turbine 1 is likely to enter an overspeed regime. The supply pressure is thus rapidly reduced in the inlet 2 in a simple and practical manner, without risk of water hammer, even in the presence of high flow rates, as is the case in a steam or compressed air turbine.

[0036] In practice, the overspeed regime is characterized by a rotational speed of the rotary shaft 4 whose value exceeds a speed threshold for which the drive turbine 1 has been designed, for example 20% above the maximum speed for which the drive turbine 1 is dimensioned. Such an overspeed regime may occur following a breakage event of the rotary shaft 4 of the turbine 1 or following the action of a decoupling device between the load 20 and the rotary shaft 4, such as connecting elements configured to break mechanically in the presence of an unbalance on the load 20. The safety state D may also be triggered in the presence of an unbalance on the test rotating machine, caused for example by the loss of a blade.

[0037] In the presence of such an event, measured for example by a speed sensor 9 of the rotating shaft 4 (see [Fig.2]), the control member 8 controls the safety state D of the pyrotechnic opening device 5. The low response time of the pyrotechnic opening device 5 allows rapid protection of the turbine 1. This makes it possible to preserve the integrity of the drive turbine 1 by avoiding its accelerated wear and / or damage. This also makes it possible to secure the test by avoiding a risk of projections into the environment of the test installation.

[0038] According to a preferred aspect illustrated in [Fig.l], the turbine 1 also comprises a braking device 7 controllable between an inactive state B illustrated in [Fig.2], and an active state A illustrated in [Fig.3], in which it applies a resistive torque R to the rotating shaft 4. The braking device 7 makes it possible, in addition to the pyrotechnic opening device 5, to secure the turbine 1 in the event of a risk of overspeed. The braking device 7 is maintained in the inactive state A during normal operation of the turbine 1, the pyrotechnic opening device 5 being in the standby state O. The control member 8 is configured to control the active state B of the braking device 7 in parallel with the safety state D of the device pyrotechnic opening 5. This makes it possible to apply a resistive torque R to the rotating shaft 4 opposite to the drive torque of the load 20, so as to reduce its rotation speed.

[0039] According to a preferred aspect, the braking device 7 is of the magnetic type, preferably eddy current. Such a frictionless braking device 7 advantageously makes it possible to better dissipate kinetic energy in the form of heat. According to a preferred aspect illustrated in FIGS. 2 and 3, to allow the turbine 1 to stop completely, the turbine 1 also comprises a stopping device 10 such as a friction brake. The stopping device 10 makes it possible, in a controllable active state, to apply a resistive torque to the rotating shaft 4 in a manner complementary to the braking device 7.

[0040] According to a preferred aspect, the pyrotechnic opening device 5 extends adjacent to the inlet 2 of the drive turbine 1. This makes it possible to limit the fluid F admitted into the turbine 1 once the pyrotechnic opening device 5 is in the safety state D. The protection of the turbine 1 is all the more effective.

[0041] In the example of [Fig. 2], the pyrotechnic opening device 5 is in the form of a valve mounted in the supply line 15 and comprising one or more flaps 6, 13 configured to be actuated pyrotechnically to open one or more discharge outlets 11, 12. In the standby state O, the discharge outlet(s) 11, 12 are kept closed by the flap(s) 6, 13, for example by means of a return member such as a spring mechanically retaining the flaps 6, 13 in a closed position.

[0042] The pyrotechnic actuating means are for example in the form of one or more explosive cartridges configured to be electrically ignited by an electric current, preferably supplied by the control member 8. This makes it possible to release a high-pressure gas into a valve body, at a pressure greater than the return force of the spring, which makes it possible to move a piston secured to the valve 6, 13 to open the discharge outlet 11, 12. The pressure of the fluid F also participates in opening the valve(s) 6, 13. Such a pyrotechnic valve 5 is for single use. Once triggered, the pyrotechnic valve 5 remains in the safety state D.

[0043] Alternatively, the discharge outlet(s) 11, 12 are in the form of openings formed in the wall of the supply pipe 15 and closed by one or more valves 6, 13, such as covers, configured to be actuated pyrotechnically. The pyrotechnic actuating means are, for example, in the form of single-use explosive bolts. The pressure of the fluid F helps to open the pyrotechnically actuated valves 6, 13.

[0044] According to a preferred aspect illustrated in Figures 2 and 3, the pyrotechnic opening device 5 comprises a first exhaust outlet 11 and a second exhaust outlet 12. The first exhaust outlet 11 opens into a cooling pipe 14 which itself opens at the braking device 7, and preferably also at the stopping device 10. The second exhaust outlet 12 opens externally to the drive turbine 1. In the case of a steam or compressed air type turbine 1, the exhaust outlet 12 can open in a simple and practical manner into the test installation. In the standby state O, a first valve 6 and a second valve 13 respectively keep the first exhaust outlet 11 and the second exhaust outlet 12 closed.

[0045] With reference to [Fig. 3], preferably, in the safety state D, the first discharge outlet 11 is open if the temperature T of the drive fluid F, measured for example by a temperature sensor in the supply line 15, is greater than a predetermined threshold Tref. The second discharge outlet 12 is preferably kept closed. This makes it possible to guide the drive fluid F into contact with the braking device 7 in the active state A, so as to cool it by thermal convection. The fluid F is thus advantageously reused for cooling, which allows energy savings.

[0046] With reference to [Fig. 4], preferably, in the safety state D, the second discharge outlet 12 is open if the temperature T of the drive fluid F is higher than the predetermined threshold Tref, the first discharge outlet 11 being kept closed. The drive fluid F is thus discharged to the outside if its temperature does not allow effective cooling of the braking device 7.

[0047] Alternatively, the pyrotechnic opening device 5 comprises a single discharge outlet 12 opening into a cooling pipe 14 itself opening at the braking device 7, and preferably also at the stopping device 10. In the safety state D, the drive fluid F is thus systematically reused for cooling purposes.

[0048] Alternatively, the pyrotechnic opening device 5 comprises a single discharge outlet 11 opening externally to the drive turbine 1 to discharge the drive fluid F into the external environment in the safety state D.

[0049] Alternatively, the pyrotechnic opening device 5 comprises a single discharge outlet in which a valve configured to guide the drive fluid F is mounted: • in the cooling line 14 if the temperature T of the fluid F is lower than the predetermined threshold Tref, and • towards the outside if the temperature T of the fluid F is higher than the predetermined threshold Tref.

[0050] According to a preferred aspect illustrated in Figures 3 and 4, the pyrotechnic opening device 5 is also configured, in the safety state D, to prohibit the admission of the drive fluid F into the inlet 2, for example by means of a third valve 16 whose closure is actuated pyrotechnically. This makes it possible to cut off the power supply to the turbine 1 without causing water hammer, thanks to the redirection of the fluid F into the discharge outlet(s) 11, 12, in particular for high flow rates of fluid F.

[0051] With reference to [Fig. 5], the invention also relates to a method for protecting the turbine 1. Initially, as illustrated in [Fig. 2], the pyrotechnic opening device 5 is in the standby state O and guides the drive fluid F into the inlet 2 according to a normal operation of driving the load 20 with the rotating shaft 4. The discharge outlet(s) 11, 12 are kept closed by the valves 6, 13. The third valve 16 is kept open. Preferably, the braking device 7 and the stopping device 10 are initially in the inactive state B and do not exert any resistive torque R on the rotating shaft 4.

[0052] As illustrated in [Fig.5], the method comprises: • a pyrotechnic triggering step El of the safety state D of the pyrotechnic opening device 5 following detection of a risk of overspeed of the drive turbine 1, and • preferably, a control step E2 of the active state A of the braking device 7, and preferably of the stopping device 10.

[0053] According to a preferred aspect illustrated in Figures 3 and 4, the control member 8 receives one or more parameters for monitoring the state of the turbine 1, such as the speed of the rotating shaft 4, provided for example by the speed sensor 9. This makes it possible to check at regular or irregular intervals the correct operation of the turbine 1. Initially, the parameters received OK are below a predetermined overspeed threshold. The protection method is implemented upon receipt of one or more POK parameters exceeding the predetermined overspeed threshold, or for example in the presence of an unbalance on the rotating test machine.

[0054] According to a preferred aspect, the triggering step E1 and the control step E2 are implemented simultaneously for immediate protection. Preferably, the pyrotechnic triggering step E1 consists of opening the first discharge outlet 11 if the temperature T of the fluid F is higher than the predetermined threshold Tref and the second discharge outlet 12 otherwise. Also preferably, the pyrotechnic triggering step E1 also consists of prohibiting the admission of fluid F into the inlet 2, for example by closing the third valve 16.

[0055] Such a method advantageously allows immediate safety of a turbine 1 in the event of an event likely to generate an overspeed or in the presence of an unbalance on the rotating test machine. In addition, the reuse of the fluid F to cool the braking device 7 makes it possible to dispense with a dedicated cooling device. The turbine 1 thus has a reduced size, a reduced cost and is less energy-intensive.

Claims

Claims

1. Drive turbine (1) comprising an inlet (2) configured to admit a drive fluid (F) and characterized in that it comprises a pyrotechnic opening device (5) configured: • in a standby state (0), to authorize the admission of the drive fluid (F) into the inlet (2), and • in a safety state (D), to pyrotechnically trigger the opening of at least one discharge outlet (11, 12) of the drive fluid (F) emerging from the inlet (2).

2. Drive turbine (1) according to claim 1, wherein the pyrotechnic opening device (5) is in the form of a valve comprising at least one flap (6, 13) closing the discharge outlet (11, 12) and configured to be opened by pyrotechnic actuation.

3. Drive turbine (1) according to one of claims 1 and 2, wherein, in the safety state (D), the pyrotechnic opening device (5) prevents the admission of the drive fluid (F) into the inlet (2).

4. Drive turbine (1) according to one of claims 1 to 3, comprising: • a rotating shaft (4) and a braking device (7) controllable between an active state (A), in which it applies a resistive torque (R) to the rotating shaft (4), and an inactive state (B), • a cooling pipe (14) into which the discharge outlet (11) opens and configured to guide the drive fluid (F) into contact with the braking device (7).

5. Drive turbine (1) according to claim 4, wherein the braking device (7) is of the magnetic type, preferably eddy current.

6. Drive turbine (1) according to one of claims 4 and 5, comprising a first discharge outlet (11) opening into the cooling pipe (14) and a second discharge outlet (12) opening out of the drive turbine (1), the device

7.

8.

9.

10. pyrotechnic opening device (5) being configured, in the safety state (D), to prohibit the admission of the drive fluid (F) into the first discharge outlet (11) if the temperature (T) of the drive fluid (F) is greater than a predetermined threshold (Tref). Drive turbine (1) according to one of claims 1 to 6, wherein the pyrotechnic opening device (5) is mounted adjacent to the inlet (2) of the drive turbine (1). Drive turbine (1) according to one of claims 1 to 7, of steam or compressed air type. Test bench (30) comprising a drive turbine (1) according to one of claims 1 to 8. Method for protecting a drive turbine (1) according to one of claims 1 to 8, in which the pyrotechnic opening device (5) is initially in the standby state (O), the method comprising a step of pyrotechnic triggering (El) the safety state (D) of the pyrotechnic opening device (5) following detection of a risk of overspeed of the drive turbine (1).

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