WIND MODULE FOR AN AIRCRAFT TURBOMACHINE TEST BENCH

Abstract

The invention relates to a blower module (110) comprising: - a drive shaft (114) movable in rotation about a main axis (X), - a blower (110) driven by the drive shaft and comprising a blower disc (116) centered on the main axis (X) and carrying blades (118) extending substantially radially outwards from the blower disc, the blower disc comprising a concentric inner wall (116A) and an outer wall (116B), and - a drum brake (140) configured to brake the rotation of the blower disc in case of an anomaly, said brake being arranged radially inside the blower disc and comprising a flange (142) centered on the main axis (X), a drum (144) integral with the inner wall of the blower disc and brake segments (146) arranged between the flange and the drum and configured to cooperate with the drum in case of a malfunction. Figure for the abbreviation: Figure 4

Description

Title of the invention: WIND MODULE FOR AN AIRCRAFT TURBOMACHINE TEST BENCH Technical field

[0001] The present invention relates to a blower module, in particular for an aircraft turbomachine test bench. Prior art

[0002] An aircraft turbomachine conventionally comprises, from upstream to downstream with reference to the flow of gases in the turbomachine, a blower, one or more compressors, an annular combustion chamber, one or more turbines and a gas ejection system.

[0003] To facilitate its manufacture and assembly, a turbomachine is generally modular, meaning that it comprises several modules that are manufactured independently of each other and then assembled together. The modularity of a turbomachine also facilitates its maintenance.

[0004] In the present application, "blower module" means a turbomachine module which includes in particular a blower and its drive shaft.

[0005] Fig. 1 shows an example of a fan module 10 of an aircraft turbomachine 100. The module 10 comprises a fan 12 and a drive shaft 14 which extends along a main axis denoted X.

[0006] The drive shaft 14 is mobile in rotation around the main axis X and is, for example, part of a low-pressure body of the turbomachine 100.

[0007] The blower 12 comprises a blower disk 16 centered on the X axis and carrying blades 18.

[0008] Each blade 18 comprises a foot, generally dovetailed, fitted into a recess in the disc 16 and a blade which extends substantially radially outwards from the disc 16.

[0009] The disc 16 is rotationally secured to the drive shaft 14 by a set of splines. In this type of aircraft turbomachine, the fan disc 16 is directly connected to the drive shaft 14.

[0010] In the present application, the focus is more particularly on a fan module for a test bench or for a test bench turbomachine.

[0011] This type of fan module generally comprises a thrust balance 19 mounted between the fan 12 and the drive shaft 14.

[0012] A thrust balance (or component balance or rotating measuring balance) is a device that is attached to a propulsion stage via dyna meters used for the determination of forces and moments generated in static operation.

[0013] During the operation of a fan module on a test bench, a fan blade may accidentally break, causing significant mechanical and aerodynamic imbalance on the fan drive shaft. Such imbalance results in loads and vibrations on the drive shaft bearings, which are transmitted via their support parts to the fixed structure of the turbomachine, which must be dimensioned accordingly. Such a blade breakage can also occur during the operation of an aircraft turbomachine, i.e., in flight. This can lead to shaft failure and the release of the fan module and / or limit the operability and performance of the fan module, the turbomachine, and the aircraft.

[0014] To overcome this problem, it is known to equip the fan module for a test bench with a fan disk retaining element also called a catcher device. Such a retaining element 20 is shown in [Fig.l]. It is a rigid part configured to axially retain the fan 12 and in particular the fan disk 14 in the event of a problem in order to prevent the latter from being ejected from the test bench and thus protect the test bench.

[0015] More specifically, in the event of the loss of at least one fan blade 18, the radial force in the plane of the fan is such that it leads to the rupture of fusible screws 22 provided for this purpose, which allow the fan rotor disc to be separated from the thrust balance 19. However, the fan 12 is still driven in free rotation, also known as "windmilling." This free rotation causes the fan 12 to move upstream of the fan module 10, which can lead to its ejection from the test bench.

[0016] In addition, this "fan catcher" retaining element is only suitable for small diameters of blower disc. Furthermore, it is very difficult to correlate a mechanical calculation with a failure scenario, particularly because it is a multi-parameter calculation. Indeed, for such a calculation, assumptions are made that take into account certain parameters, such as the number of broken blades (a broken blade can break neighboring blades), the machine's rotational speed at the time of breakage, etc., while other parameters are omitted, for example, the case of bird ingestion, which would add an impact force transmitted through the blade. If the machine is running at too high a speed, the energy from the blade loss and the resulting imbalance will be greater and will promote the failure of the shear screw. Conversely, an underspeed might not trigger the failure of the shear screw but could create a cyclic imbalance that would damage the bearings. Finally, the behavior of the detached blower at the beginning of overspeed is unknown and it would be very useful to be able to study it.

[0017] In this context, it is interesting to overcome at least some of the drawbacks of the prior art, by integrating a simple and effective safety function - on a blower module in particular for a test bench. Summary of the invention

[0018] The present invention proposes a solution to at least part of the aforementioned problems, which is efficient and relatively easy to integrate, and therefore economical.

[0019] To this end, the invention relates to a blower module comprising: - a drive shaft movable in rotation about a main axis, - a blower driven by the drive shaft and comprising a blower disc centered on the main axis and carrying blades extending substantially radially outwards from the blower disc, the blower disc comprising a concentric inner wall and an outer wall, and - a drum brake configured to brake the rotation of the blower disc in case of an anomaly, said brake being arranged radially inside the blower disc and comprising a flange centered on the main axis, a drum integral with the inner wall of the blower disc and brake segments arranged between the flange and the drum and configured to cooperate with the drum in case of an anomaly.

[0020] The invention thus makes it possible to achieve the aforementioned objective. In particular, the addition of a drum brake type braking system to the blower module according to the invention makes it possible to effectively brake the blower disc in the event of a malfunction and thus makes it possible to easily solve the problem of blower disc ejection and consequently to protect the test bench equipped with the blower module or the turbomachine, as applicable.

[0021] In the case of a blower module for a test bench, the measuring instruments, and in particular the thrust balance, are protected. Furthermore, it is then possible to study the behavior of the blower at the beginning of overspeed.

[0022] In the case of a fan module for a turbomachine, braking the fan disc advantageously makes it possible to reduce the air supply to the rest of the turbomachine, which will stop naturally. This thus makes it possible to remove the fan disc and easily change the worn and / or damaged parts, then to replace the fan disc without any parts with high manufacturing costs and time being damaged.

[0023] The blower module according to the invention may comprise one or more of the following features, taken individually or in combination with each other in all technically possible combinations:

[0024] - the drum is formed in continuity of material with the fan disc.

[0025] - the drum brake is of the cam type actuated by a mechanical control.

[0026] - the drum brake is of the piston type actuated by a hydraulic control.

[0027] - the blower module comprises a sensor for detecting an anomaly, said sensor being arranged upstream of the fan disc and configured to actuate the drum brake in the event of an anomaly.

[0028] - the sensor is chosen from the list comprising: - - a contact sensor configured to detect movement of the fan disc upstream of the fan module, - - a speed sensor configured to detect drive shaft overspeed, - - a sensor for detecting an imbalance in the blower.

[0029] The invention also relates to a turbomachine, in particular for aircraft, comprising a blower module according to the invention and as described above.

[0030] The invention also relates to a test bench comprising a turbomachine according to the invention and as described above or a blower module according to the invention and as described above and an air supply system for the blower module, the supply system being of the compressed air or steam type.

[0031] The test bench according to the invention may comprise one or more of the following features, taken individually or in combination with each other in all technically possible combinations:

[0032] - the test bench includes an ultra-fast pyrotechnic discharge system of the air turbine power supply system in case of anomaly, the pyrotechnic system being arranged upstream of the blower module inlet.

[0033] - the test bench includes a redirection device configured to redirect ra quickly the fluid from the fuel system to the drum brake. Brief description of the drawings

[0034] The present invention will be better understood and other details, features and advantages of the present invention will become more apparent upon reading the description of a non-limiting example that follows, with reference to the accompanying drawings in which: - the [Fig.1], already described, is a partial schematic half view in axial section of a fan module of an aircraft turbomachine according to the prior art; - [Fig.2], a partial schematic half view in axial section of a blower module according to the invention; - [Fig.3], illustrates a three-dimensional exploded view of a fan module of the [Fig.2] equipped with a drum brake; - [Fig.4] illustrates a cross-sectional view of a blower module similar to that of [Fig.3] when the brake shoes of the drum brake are in their rest position; - [Fig.5] illustrates a cross-sectional view of the blower module of [Fig.4] when the brake shoes of the drum brake are in their actuated position; - [Fig.6] represents a schematic view of a test bench according to the invention.

[0035] Elements having the same functions in different implementations have the same references in the figures. Description of the embodiments

[0036] [Fig. 1] has already been described in the above.

[0037] Reference is now made to Figures 2 and 3, which depict an embodiment of a fan module 110 for a test bench 200 of an aircraft turbomachine, for example, of the twin-spool, twin-flow type. Such a turbomachine generally comprises such a fan module 110 and a primary casing. The primary casing includes, in the direction of gas flow, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and a gas exhaust nozzle.

[0038] By blower, we mean any type of blower whether it is enclosed or not, that is to say that this term also covers the case of a propeller.

[0039] The test bench 200 includes module 110 and possibly other modules of the turbomachine. It may also include the turbomachine as a whole.

[0040] The purpose of a test bench is, as its name suggests, to carry out functional tests of one or more modules of the turbomachine.

[0041] For this purpose, the test bench according to the invention generally comprises an air turbine supplied by a pressurized air line or an electric motor.

[0042] The blower module 110 classically comprises a blower 112 and a drive shaft 114 which extends along a main axis denoted X.

[0043] The drive shaft 114 is free to rotate about the main axis denoted X, which corresponds to the longitudinal axis of the module and therefore of the turbomachine. Only a portion of the upstream end of the drive shaft 114 is visible in [Fig.2]. For example, the drive shaft 114 may be a low-pressure shaft of a low-pressure body of the turbomachine, this shaft being intended to connect a rotor of a low-pressure compressor to a rotor of a low-pressure turbine of the turbomachine. The drive shaft 114 is guided in rotation within an intermediate housing of the blower module by a series of bearings. Conventionally, each bearing is mounted in a bearing support.

[0044] The fan 112 comprises a fan disk 116 centered on the X-axis and carrying blades 118 extending substantially radially outwards from the disk. When the fan disk 116 is rotated, the blades drive the airflow into the primary and secondary flow spaces of the turbomachine.

[0045] The terms "lower," "inner," or "internal" refer to any positioning close to the X-axis along the radial direction R, while "upper," "outer," or "external" refer to any positioning further from the X-axis along the radial direction than the lower positioning. Furthermore, the terms "upstream" and "downstream" are defined with respect to the gas flow within the blower module, with the gases flowing from upstream to downstream.

[0046] Each blade 118 comprises a foot, generally dovetailed, fitted into a recess in the disc 116 and a blade which extends substantially radially outwards from the disc 116.

[0047] The disc 116 is rotationally secured to the drive shaft 114 by a set of splines. In this type of aircraft turbomachine, the fan disc 116 is directly connected to the drive shaft 114.

[0048] The blower disc 116 is annular and radially delimited by an inner wall 116A and an outer wall 116B. The two inner and outer walls are therefore concentric and have axis X.

[0049] Conventionally and as indicated previously, the fan disk 116 comprises at its external periphery, that is to say on the external wall 16B, cells for receiving the roots of the blades 118. The roots of the blades 118 and the cells of the disk 116 have complementary shapes and the fitting of the roots in the cells is sufficient to ensure the retention of the blades 118 on the disk 116 in the radial direction R.

[0050] The fan blades 118 can have variable pitch as illustrated in [Fig. 2]. The module then includes a mechanism for modifying the blade pitch angle to adapt the thrust generated by the fan according to the different flight phases. The angular pitch of the fan blades also optimizes the fan's efficiency as a function of aircraft speed and optimizes the turbomachine's pumping margin to reduce its fuel consumption during the different flight phases.

[0051] Furthermore, the blower module 110 includes a thrust balance 119 mounted between the blower 112 and the drive shaft 114. The thrust balance is configured to determine the forces and moments of the blower generated during static operation. In a known manner, and more specifically, the thrust balance 119 comprises a first rotating thrust balance configured to capture the deformation on the rotating parts of the blower module and a second static thrust balance configured to capture the deformation on the static skins of the module of the fan. It also includes a telemetry device for transmitting the rotating information acquired by the rotating thrust balance to a stator part and then to an integrated computer.

[0052] The thrust balance 119 is centered on the main axis X. The first rotating thrust balance and the telemetry device are connected to the fan shaft by splines and held in position by a large diameter nut.

[0053] In addition, to limit the dynamic loads of the fan and to lighten the engine, the module further comprises a decoupling device 120 which makes it possible to limit the forces by decoupling the bearings which support the drive shaft 114 of the fan 110 relative to the intermediate casing of the fan module. For this purpose, the decoupling device 120 comprises at least one shear screw 122 arranged and configured to detach the rotor disk of the fan from the thrust balance 119 of the fan module of the turbomachine.

[0054] According to the invention, the blower module 110 further comprises a drum brake 140 configured to brake the rotation of the blower disc 116 in the event of a malfunction. A malfunction is understood to mean a significant imbalance of the blower, for example, following the accidental breakage of a blower blade, a displacement of the blower disc towards the upstream side of the module, or an overspeed of the drive shaft.

[0055] The drum brake 140 is advantageously arranged radially inside the fan disc 116. The drum brake 140 comprises a flange 142, a drum 144 integral with the inner wall 116A of the blower disc and brake segments 146 arranged between the flange 142 and the drum 144. The brake segments 146 are configured to cooperate with the drum in case of malfunction.

[0056] The flange 142 is centered on the main axis X and extends in a plane perpendicular to the main axis.

[0057] According to the example illustrated in [Fig. 2], the drum 144 is formed in continuous material with the blower disc 116 and more specifically with the inner wall 116A of the blower disc. In other words, the inner wall 116A of the blower disc forms the drum 144. That is to say, the blower disc 116 and the drum 144 form a single piece.

[0058] Alternatively, and according to another example illustrated in [Fig. 3], the blower disc 116 and the drum 144 are two separate parts. The drum 144 is integral with the inner wall 116A of the blower disc. Furthermore, the brake system may include a replaceable intermediate piece for connecting the drum 144 to the inner wall 116A of the blower disc. This piece may advantageously be ventilated to cool the drum brake during operation. For example, this piece may have a surface made of contact with the drum surface and having axial holes to dissipate friction heat.

[0059] The brake segments are more clearly visible in [Fig. 3]. In the illustrated example, the drum brake 140 has two brake segments. However, a greater number of brake segments can be fitted to the drum brake 140.

[0060] Each brake segment 146 comprises a brake shoe 147 equipped with a brake lining 148, an actuator 149 and a return means 150.

[0061] The brake shoe 147 is movable between a rest position and an actuated position in which the shoe 147 is configured to rub, via the brake lining 148, against an inner surface of the brake drum 144 in the event of a malfunction. The brake shoes are at least partially complementary in shape to the inner wall of the drum, i.e., in the form of an arc.

[0062] Figure 4 illustrates a cross-sectional view of a blower module similar to that of Figure 3 when the brake shoes 147 of the drum brake 140 are in their rest position. In this example, only four vanes 118 are partially shown. Figure 5 represents the blower module of Figure 4 when the brake shoes 147 of the drum brake 140 are in their actuated position.

[0063] The actuator 149 is arranged between the flange 142 and the brake shoe 146 to move said shoe from the rest position to the actuated position in case of an anomaly.

[0064] In the example illustrated in [Fig. 3], the drum brake 150 is of the cam-operated type, actuated by a mechanical control. In other words, the drum brake 140 has one or two cams arranged and configured to push the shoes against the drum to brake the blower disc.

[0065] Alternatively, the drum brake may be of the hydraulically actuated piston type. In this case, the drum brake has one or two pistons arranged and configured to push the shoes against the drum to brake the blower disc. This is notably the case for the drum brake equipping the blower module illustrated in Figures 4 and 5. In the example shown, the actuator 149 is a hydraulic cylinder. However, other types may be used.

[0066] The return means 150, for example a spring, is arranged between the flange 142 and the brake shoe 146 to return the brake shoe 147 to its rest position in which the brake shoe 147 is away from the drum 144. The return means 150 is arranged and configured to prevent the shoes 147 from moving spontaneously towards the drum 144 and also ensures automatic movement to the rest position.

[0067] The brake segment actuators 146 are actuated by a blower module control unit based on information provided by a sensor of anomalies 160 equipping the blower module. The sensor 160 is for example arranged upstream of the blower disc 116 and configured to activate the drum brake 140 in case of an anomaly.

[0068] Preferably, the sensor 160 is a contact sensor configured to detect a movement of the blower disc 116 upstream of the blower module.

[0069] Alternatively, the sensor 160 is a speed sensor configured to detect an overspeed of the drive shaft or the blower disc.

[0070] Alternatively, the sensor 160 is a sensor for detecting an imbalance in the blower 110. Such a sensor is arranged as close as possible to the source of the imbalance, i.e., the rotor in the disc area and preferably on the shaft. The imbalance detection sensor may comprise several gauges adapted to measure a stretch or several proximity sensors arranged between the shaft and the stator.

[0071] During operation of a fan module on a test bench or during operation of an aircraft turbomachine, a fan blade may accidentally break, causing significant mechanical and aerodynamic imbalance on the fan drive shaft. In the case of an imbalance detection sensor or a speed sensor configured to detect overspeed of the drive shaft or blower disc, the sensor detects an imbalance or imminent blade breakage that can cause overspeed of the blower, enabling the drum brake 140 to be activated, and more specifically the drum brake 140 actuators.

[0072] In the case of a contact sensor, the imbalance caused by the breakage of a blade leads to the rupture of a shear screw 122, which releases the blower disc 116 carrying the other blades 118. The free rotation of the blower, the aerodynamics of the blower blades, and the absence of fasteners move the blower (disc and blades) upstream of the blower module 110. This movement is detected by the contact sensor arranged upstream of the blower disc 116, which then activates the drum brake 140, and more specifically the drum brake actuators 140.

[0073] When the drum brake 140 is actuated, the cam or piston actuators move the brake shoes towards the inner surface of the drum. The brake linings make contact with the blower disc via the drum, centering it and slowing it down until it regains the speed of the drive shaft to a stop, or bringing it to a complete stop. Thus, the action of the linings against the blower disc allows the blower to return from an "overspeeding" speed to a "normal decreasing" speed and keeps the disc "free," centered on the shaft and held in its axial position.

[0074] The test bench, in particular the thrust balance and other measuring tools, is thus protected.

[0075] [Fig. 6] illustrates a test bench 200 according to the invention. As indicated previously, the test bench comprises an air turbine 212 supplied by a pressurized air line 215 or an electric motor forming an air supply system 210 for the blower module.

[0076] The 210 power supply system is of the compressed air or steam type.

[0077] Furthermore, when the test bench 200 comprises other modules of the turbomachine and in particular a turbine module, the test bench 200 advantageously comprises a pyrotechnic system for ultra-rapid discharge of the supply system 210 of the air turbine 212 in the event of an anomaly. The pyrotechnic system is arranged upstream of the inlet of the fan module.

[0078] Indeed, the power supply to a compressed air or steam turbine cannot be cut off as quickly as the fuel supply to a gas or oil turbine since the high flow valves of the power system have a certain response time. In addition, there necessarily remains fluid under pressure downstream of these valves.

[0079] Such a pyrotechnic pressure relief device according to the invention located just before the turbine inlet has a definite advantage in terms of reaction time for cutting off the pressurized air / steam supply in the event of loss of resistive torque on the turbine.

[0080] In addition, the test bench advantageously includes a redirection device configured to quickly redirect the fluid from the supply system to the drum brake.

[0081] In the preceding description, the fan module is installed on a test bench. However, as previously stated, the test bench may also include other modules of the turbomachine. It may also include the turbomachine as a whole. Furthermore, such a fan module can be fitted to a turbomachine. In these latter cases, the drum brake can be attached directly to a stator element of the module for use as a turbomachine drive, thus allowing the fan disc to be slowed down or completely braked according to the desired braking force. Without the fan being driven, the rest of the turbomachine will no longer receive sufficient air and will stop naturally. This allows the fan disc to be removed and worn and / or damaged parts to be easily replaced, and then the fan disc to be replaced without damaging any costly and time-consuming parts.

Claims

Claims

1. A fan module (110) comprising: - a drive shaft (114) rotatable about a main axis (X), - a fan (110) driven by the drive shaft and comprising a fan disc (116) centered on the main axis (X) and carrying blades (118) extending substantially radially outward from the fan disc, the fan disc having a concentric inner wall (116A) and an outer wall (116B), and - a drum brake (140) configured to brake the rotation of the fan disc in the event of an anomaly, said brake being arranged radially inside the fan disc and comprising a flange (142) centered on the main axis (X), a drum (144) secured to the inner wall of the fan disc and brake segments (146) arranged between the flange and the drum and configured to cooperate with the drum in the event of an anomaly.

2. A blower module according to claim 1, wherein the drum (144) is formed in material continuity with the blower disc (116).

3. A blower module according to claim 1 or 2, wherein the drum brake (140) is of the cam type actuable by a mechanical control.

4. A blower module according to claim 1 or 2, wherein the drum brake is of the piston type actuable by a hydraulic control.

5. Blower module according to one of the preceding claims, comprising a sensor (160) for detecting an anomaly, said sensor being arranged upstream of the blower disc and configured to actuate the drum brake (140) in the event of an anomaly.

6. Blower module according to claim 5, in which the sensor (160) is chosen from the list comprising: - a contact sensor configured to detect a movement of the blower disc upstream of the blower module, - a speed sensor configured to detect an overspeed of the drive shaft, - a sensor for detecting an imbalance of the blower.

7. Turbomachine, in particular for an aircraft, comprising a module of blower according to one of the preceding claims.

8. Test bench comprising a turbomachine according to claim 7 or a fan module according to one of claims 1 to 6 and an air supply system for the fan module comprising an air turbine, the supply system being of the compressed air or steam type.

9. Test bench according to claim 8, comprising a pyrotechnic system for ultra-rapid discharge of the air turbine supply system in the event of an anomaly, the pyrotechnic system being arranged upstream of the inlet of the fan module.

10. A test bench according to claim 8 or 9, comprising a redirection device configured to rapidly redirect fluid from the supply system to the drum brake.

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