Turbomachine propeller comprising a high-power de-icing system

Abstract

An aircraft turbomachine propeller comprising a propeller cone and blades, the propeller cone and the blades comprising a plurality of heating members (220), and a system (222) for supplying electrical power to said plurality of heating members, mounted in the propeller cone and configured to generate electrical energy autonomously from the rotation of a main shaft of the turbomachine (216) driving the propeller in rotation, the electrical power supply system comprising an electric machine (290) comprising a rotating stator (230B) fulfilling an armature function and constrained to rotate with the main shaft of the turbomachine, and a rotor (230A) performing an inductor function and constrained to rotate with a high-speed auxiliary shaft (232) rotating at a rotational speed greater than the rotational speed of the main shaft of the turbomachine.

Description

[0001] Description

[0002] Title of the invention: Turbomachine propeller comprising a high-power de-icing system

[0003] Technical Field

[0004] The present invention relates to the field of electrical (electrothermal) deicing of the cone and propeller blades of an aircraft turbomachine.

[0005] Prior art

[0006] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those currently in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0007] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of these aircraft.

[0008] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity. This sustained research and development work covers new generations of aircraft turbomachines, the weight reduction of aircraft, in particular through the materials used and lighter onboard equipment, the development of the use of electric technologies to provide propulsion, and, as essential complements to technological progress, aeronautical biofuels.

[0009] However, on electric or hybrid aircraft as on conventional aircraft, there are several surfaces to be protected against ice on the fixed and rotating parts of the turbomachine when it operates in icing conditions (altitude, cloud, fog). The accumulation of ice in fact impairs the dynamic performance of the propeller blades by creating an imbalance and by degrading their aerodynamic profile. The protection then envisaged to remedy this accumulation is generally exclusively electrothermal based on electric heating mats formed of layers of resistors covering the surfaces to be protected mounted in different areas of the turbomachine. These resistors are interconnected by power and signal harnesses over long distances and pass through different areas of the turbomachine.These harnesses also require specific protections, in particular shielding to protect against external attacks and also protect surrounding systems against electromagnetic disturbances, which by significantly increasing their size make their routing and integration very difficult or sometimes impossible in the very constrained space of a turbomachine.

[0010] It is also known, to ensure the transfer of power and therefore convey the electrical energy from the fixed part to the rotating part where the electric heating mats are installed, to use a device called a "slip ring" whose principle consists of rubbing several fixed conductive rings secured to the fixed part on circular conductive tracks secured to the rotating part, in order to create an electrical connection between the fixed part and the rotating part of the turbomachine. However, the major disadvantage of this solution lies in its very limited service life due to the wear of the parts in continuous friction, which therefore generates unacceptable operating costs on a single-aisle commercial aircraft of the A320 or B737 type where the rotating part endures multiple rotations.

[0011] There is therefore still a need today for an electrical generation solution synchronized with the rotating reference of the propeller blades, making it possible to do without power harnesses between the fixed reference and the rotating reference of the turbomachine and which is also particularly suitable for cases where the power required for de-icing is very high.

[0012] The invention application described in this document advantageously proposes a solution for reducing mass, offering gains enhanced by a better balance in terms of consumption at the level of the turbomachine.

[0013] Statement of the invention

[0014] To this end, the invention is the result of technological research aimed at significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of these aircraft.

[0015] To this end, the main aim of the present invention is to generate electrical power directly in the rotating reference frame without an additional transfer mechanism and this from mechanical power taken from a rotating part of the turbomachine. Another aim is to enable control of the level of power taken according to the demand of the supervisory computer of the turbomachine de-icing system. Yet another aim is to propose a compact system facilitating its installation in the nose cone and maintenance operations on the propeller.

[0016] These aims are achieved by an aircraft turbomachine propeller comprising a propeller cone and blades, the propeller cone and the blades comprising a plurality of heating members, and an electrical power supply system for said plurality of heating members, mounted in the propeller cone and configured to generate electrical energy autonomously from the rotation of a main shaft of the turbomachine driving the propeller in rotation, the electrical power supply system comprising an electrical machine comprising a rotating stator fulfilling an armature function and integral in rotation with the main shaft of the turbomachine, and a rotor fulfilling an inductor function and integral in rotation with a fast auxiliary shaft rotating at a rotation speed greater than the rotation speed of the main shaft of the turbomachine.

[0017] The autonomous power supply, optimized in mass and size, thus produced facilitates integration into the front cone (rotating part) of the turbomachine and makes it possible to overcome the constraint of routing the harnesses through several modules of the turbomachine despite the harsh environment to which it is subjected.

[0018] The turbomachine and its main shaft which drive the propeller are external to the propeller according to the invention. The propeller of the invention is adapted for coupling with this shaft, in other words the propeller is configured to be driven in rotation with a main shaft of the turbomachine.

[0019] Preferably, the rotation of the fast auxiliary shaft is obtained by a multiplier mounted between the main shaft and a fixed shaft. The multiplier may be a multiplier with reversing direction of rotation.

[0020] According to the embodiment envisaged, the electrical machine is either a three-stage synchronous generator comprising a synchronous machine, a main exciter generator and a secondary exciter generator associated with a control module; or a three-stage synchronous generator comprising two generators connected in cascade and an exciter associated with a control module. The secondary exciter generator and the exciter preferably comprise an inductor in the form of a permanent magnet rotor.

[0021] In the first embodiment, an armature of the main exciter generator and an armature of the secondary generator are integral with the high-speed auxiliary shaft, and an armature of the main exciter generator, an armature of the secondary generator and the control module are integral with either the main shaft or a fixed shaft.

[0022] In the second embodiment, an inductor of a first generator is polyphase and powered directly by a polyphase armature of a second generator and the phases of the polyphase armature of the second generator are crossed so that the direction of rotation of the rotating field of the polyphase inductor of the first generator is reversed relative to the rotating field of the polyphase armature of the second generator.

[0023] Preferably, to deliver a current or voltage measurement to the control module, a non-rotating contactless sensor is mounted between the fixed shaft and the main shaft when the control module is secured to the fixed shaft.

[0024] Advantageously, the multiplier is integrated into the electric machine or into a speed reduction box of the turbomachine.

[0025] The invention also relates to an aircraft turbomachine comprising a propeller as mentioned above.

[0026] Brief description of the drawings

[0027] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting character and in which:

[0028] [Fig. 1] Figure 1 is a schematic view of the front part of an aircraft turbomachine with propeller according to the invention,

[0029] [Fig. 2A] Figure 2A shows a first example of the embodiment of the power supply system for the heating elements ensuring the defrosting of the propeller of Figure 1 in the case where the multiplier is internal to the electric machine,

[0030] [Fig. 2B] Figure 2B shows the first example of embodiment of Figure 2A in the case where the multiplier is external to the electric machine,

[0031] [Fig. 3] Figure 3 shows a second example of the system for supplying the heating elements ensuring the defrosting of the propeller of Figure 1, and [Fig. 4] Figure 4 shows a third example of the system for supplying the heating elements ensuring the defrosting of the propeller of Figure 1.

[0032] Description of the embodiments

[0033] The principle of the invention is based on the use of an electrical machine, the armature of which (considered as the stator of the machine) is rotating in the same frame of reference as the loads to be supplied and the inductor, also rotating (and considered as the rotor of the machine) is integral with a fast auxiliary shaft having a speed differential greater than that existing between the armature and the inductor, when the inductor is integral with the fixed frame of reference of the turbomachine.

[0034] Thus it becomes possible to increase the differential speed which is the sum (sum taking into account the direction of rotation, i.e. whether the shaft is counter-rotating or not) of the speed of the slow shaft (carrying the loads) and the speed of the fast auxiliary shaft, at the air gap between the armature and the inductor of the machine. This makes it possible to propose a solution with reduced mass and small size because at iso power and constant thermal environment, the mass and size of an electrical machine are directly linked to the differential speed seen at the air gap between the rotor and the stator.

[0035] This fast auxiliary shaft can be counter-rotating to obtain a greater speed differential (a slow shaft at 1000 rpm with a fast shaft at 20000 rpm provides a differential speed of 19000 rpm while with a counter-rotating fast shaft of the same speed the differential speed is 21000 rpm). In this configuration, the armature and the field winding rotate in opposite directions relative to a common fixed reference frame (RF). The armature is integral and therefore synchronized with the rotating part of the turbomachine driving the propeller blades and therefore in the reference frame of the loads to be supplied called the Slow Reference Frame (RL). The field winding is driven in the opposite direction to the armature at a higher speed by introducing a multiplier with reversal of direction of rotation between the armature shaft corresponding to the slow reference frame and the field winding shaft corresponding to a Fast and counter-rotating Reference Frame (RR).

[0036] Figure 1 schematically shows an aircraft turbomachine propeller. The propeller 10 comprises a propeller cone 12, extending axially along a longitudinal axis XX of the turbomachine, and blades 14 which extend substantially radially relative to the axis XX. The propeller is configured to be driven in rotation by a main shaft 16 of the turbomachine in order to rotate the blades and generate propulsion work. Conventionally, the propeller comprises a speed reduction box RGB 18 (“Reduction Gear Box” in English) mounted between the main shaft of the turbomachine and the propeller cone, in order to modify the speed ratio. In order to allow de-icing, the propeller comprises a plurality of heating members 20 which, in a known manner, are in the form of a heating mat comprising a plurality of resistors which are positioned on a leading edge of a blade 14 and on the external surface of the propeller cone 12.In the presence of icing conditions, the heating members 20 are activated intermittently in order to detach the layers of frost which are then ejected due to the centrifugal force linked to the rotation of the propeller. The propeller 10 comprises an electrical power supply system 22 to power the heating members 20 ensuring this defrosting.

[0037] According to the invention, the electrical power supply system 22 is mounted in the propeller cone 12 of the propeller and is autonomous and independent of the electrical system of the aircraft. By autonomous, it is meant that the electrical power supply system 22 generates electrical energy only from the mechanical torque provided by the main shaft 16 of the turbomachine, without resorting to an external source as in the prior art. This advantageously makes it possible to do without power supply harnesses which increase the mass, size and complexity of the electrical power supply system which can therefore be maintained and replaced in a practical and rapid manner.

[0038] Figures 2A and 2B illustrate a first example embodiment of the electrical power supply system for the heating members 220 ensuring the deicing of the propeller of the turbomachine. The electrical power supply system 222 comprises an electrical machine 290 comprising a rotating stator 230B fulfilling an armature function and rotationally fixed to the main shaft of the turbomachine 216, and a rotor 230A fulfilling an inductor function and rotationally fixed to a fast auxiliary shaft 232 rotating at a higher rotation speed and in a direction opposite to the main shaft of the turbomachine 216 (counter-rotating rotor) due to the introduction of a rotation direction reversing multiplier 234. The multiplier 234 may be internal to the electrical machine 290, as shown in Figure 2A or external to the electrical machine 290, as shown in Figure 2B.Whether internal or external to the electric machine 290, the multiplier 234 is mounted between the main shaft 216 and a fixed shaft 238, and ensures the rotation of the fast auxiliary shaft 232. In the configuration of FIG. 2B, that is to say when the multiplier 234 is external to the electric machine 290, three shafts are in interface between the electric machine 230 and the speed reduction box but in the configuration of FIG. 2A, that is to say when the multiplier 234 is internal to the electric machine 290, two shafts are in interface. This fast auxiliary shaft 232, being able to rotate in the opposite direction in the case of a counter-rotating fast auxiliary shaft, makes it possible to increase the differential speed between the armature and the inductor of the electric machine 290 and therefore to reduce its mass and size.

[0039] The coupling of the 290 electric machine upstream of the speed reduction gearbox (RGB) allows an optimization of the solution (the machine having its own bearings allows a small air gap of the order of 1 mm and less than 2 mm while freeing itself from radial and axial displacements) and a sharing of cooling resources (in particular the bearing oil already available at the RGB) while facilitating its integration at the level of the front cone (accessible area for maintenance operations). It also allows to reduce the quantity of power electronic components on the rotating parts.

[0040] In the configuration illustrated in Figure 2, the electrical machine 290 coupled to the reversing multiplier 234 is a so-called three-stage synchronous generator consisting of: the synchronous machine itself 230 composed of an internal wound inductor 230A secured to the fast auxiliary shaft 232 forming the fast reference frame RR and an external wound armature 230B secured to the main shaft 216 forming the slow reference frame RL and synchronized with the rotating reference frame of the propeller blades; of a main exciter generator 236 composed of a fixed inductor 236A secured to a fixed shaft 238 and an armature 236B secured to the fast auxiliary shaft 232 forming the fast reference frame RR, the armature 236B of the exciter supplying the inductor 230A of the synchronous machine through a rotating diode bridge 240 and secured to the fast auxiliary shaft 232;and a secondary exciter generator 242 composed of an inductor 242A in the form of a rotor with permanent magnets 244 secured to the fast auxiliary shaft 232 and a fixed armature 242B secured to the fixed shaft 238 and supplying alternating current to a control module GCU 246 (“Generator Control Unit” in English) secured to the fixed shaft 238, which improves its reliability and overall the mass of this configuration.;

[0041] The control of the electrical machine 290 is ensured by the control module 246 which is responsible for converting the alternating current received from the secondary exciter 242 into direct current to provide the continuous excitation to the fixed part of the main exciter 236 according to the current to be provided to the heating mats 220 or any other loads installed in the fixed reference. The control module 246 receives the current (or voltage) measurement of the load via a contactless rotary sensor 248 mounted between the main shaft 216 and the fixed shaft 238.

[0042] The rotation direction reversing multiplier 234 inserted between the main shaft 216 and the fixed shaft 238 and ensuring the rotation of the fast auxiliary shaft 232 has a multiplication ratio that a person skilled in the art will be able to choose according to criteria of mass reduction, size and reliability.

[0043] Figure 3 illustrates a second embodiment of the electrical power supply system 322 of the heating members 320 in which, unlike the previous one, the inductor 336B of the main exciter 336, the armature 342A of the secondary exciter 342 and the control module 346 are all three integral with the main shaft 316 instead of being with the fixed shaft 338 and are therefore located in the slow rotating frame of reference RL of the load. But the diode bridge 340 remains integral with the fast auxiliary shaft 332 and therefore rotating. The advantage compared to the previous configuration lies in the fact that the control module 346 receives the current (or voltage) measurement of the load by a direct sensor (not shown) given that it is located in the same frame of reference as the load.

[0044] In this second exemplary embodiment, the multiplier 334 is internal to the electrical machine 390. As for the first exemplary embodiment (figure 2B), the multiplier 334 can also be external to the electrical machine 390.

[0045] In these two embodiments, the size differences (although schematic) existing between the main exciters 336 and secondary exciters 342 and the main synchronous machine 390 will be noted. Typically, there is a power / size ratio of approximately 10 between the main machine and the main exciter and a ratio of approximately 1 / 100 between the main machine and the secondary exciter.

[0046] Figure 4 illustrates a third embodiment making it possible to dispense with the rotating diode bridge 240 and 340 of Figures 2A, 2B and 3 and in which the electrical machine 490 coupled to the reversing multiplier 434 is also a so-called three-stage synchronous generator but this time comprising two generators 450, 452 connected in cascade. More precisely, it is constituted by: a first generator 450 composed of a polyphase inductor 450A secured to the counter-rotating fast auxiliary shaft 432 forming the fast reference frame RR and a rotating armature 450B secured to the main shaft 416 forming the slow reference frame RL and synchronized with the rotating reference frame of the propeller blades; of a second generator 452 composed of a fixed direct current inductor 452A and a polyphase armature 452B secured to the fast auxiliary shaft 432.The armature 452B of the second generator 452 directly supplies the inductor 450A of the first generator 450 according to the known principle of cascades, and an exciter 442 composed of an inductor 442A in the form of a rotor with permanent magnets 444 secured to the fast auxiliary shaft 432 and a fixed armature 442B supplying alternating current to the control module 446 also secured to the fixed shaft 438 which is located in the fixed reference frame RF.

[0047] Two of the three phases (in the case of a three-phase generator) of the armature 452B of the second generator 452 are crossed so that the direction of rotation of the rotating field of the inductor 450A of the first generator 450 is reversed with respect to that of this armature 452B. As a result, and as is known, the mechanical speed of the support shaft (counter-rotation) and the electrical speed of the rotating field of the inductor of the main machine are added.

[0048] In this third exemplary embodiment, the multiplier 434 is internal to the electrical machine 490. As for the first exemplary embodiment (figure 2B), the multiplier 434 can also be external to the electrical machine 490.

[0049] Thus, to ensure protection against icing of the propeller of an aircraft turbomachine, the invention provides an autonomous, optimized and compact generation solution based on the principle of a fast auxiliary shaft to power the heating mats of the cone and the propeller blades and makes it possible to meet the following objectives compared to the prior art:

[0050] - synchronize the power supply to the rotating reference of the propellers without adding a transfer mechanism,

[0051] - facilitate maintenance operations by integrating the electrical power system into the propeller cone, - in an advantageous configuration, install the control module (GCU) on a fixed part to improve its reliability.

Claims

Claims

1. Propeller (10) of an aircraft turbomachine comprising a propeller cone (12) and blades (14), the propeller cone and the blades comprising a plurality of heating members (20, 220, 320, 420), and an electrical power supply system (22, 222, 322, 422) for said plurality of heating members, mounted in the propeller cone and configured to generate electrical energy autonomously from the rotation of a main shaft of the turbomachine (16, 216, 316, 416) driving the propeller in rotation, the electrical power supply system comprising an electrical machine (290, 390, 490) comprising a rotating stator (230B, 330B, 450B) fulfilling an armature function and integral in rotation with the main shaft of the turbomachine, and a rotor (230A, 330A, 450A) fulfilling an inductor function and rotationally connected to a fast auxiliary shaft (232, 332,432) rotating at a rotational speed greater than the rotational speed of the main shaft of the turbomachine.,

2. Aircraft turbomachine propeller according to claim 1, in which the rotation of the fast auxiliary shaft (232, 332, 432) is obtained by a multiplier (234, 334, 434) mounted between the main shaft (216, 316, 416) and a fixed shaft (238, 338, 438).

3. An aircraft turbomachine propeller according to claim 1 or claim 2, wherein the electrical machine (290, 390) is a three-stage synchronous generator comprising a synchronous machine (230, 330), a main exciter generator (236, 336) and a secondary exciter generator (242, 342) associated with a control module (246, 346).

4. Aircraft turbomachine propeller according to claim 3, in which an armature (336A) of the main excitation generator and an inductor (342B) of the secondary generator are integral with the fast auxiliary shaft (332), and an inductor (336B) of the excitation generator main, an armature (342A) of the secondary generator and the control module (346) are integral with the main shaft (316).

5. Aircraft turbomachine propeller according to claim 3, in which an armature (236B) of the main excitation generator and an inductor (242A) of the secondary generator are integral with the fast auxiliary shaft (232), and an inductor (236A) of the main excitation generator, an armature (242B) of the secondary generator and the control module (246) are integral with a fixed shaft (238).

6. Aircraft turbomachine propeller according to claim 1 or claim 2, wherein the electrical machine (490) is a three-stage synchronous generator comprising two generators (450, 452) connected in cascade and an exciter (442) associated with a control module (446).

7. Aircraft turbomachine propeller according to claim 6, in which an inductor (450A) of a first generator (450) is polyphase and powered directly by a polyphase armature (452B) of a second generator (452) and the phases of the polyphase armature of the second generator are crossed so that the direction of rotation of the rotating field of the polyphase inductor (450A) of the first generator is reversed relative to the rotating field of the polyphase armature (452B) of the second generator.

8. An aircraft turbomachine propeller according to claim 3 or claim 6, wherein the secondary exciter generator (242, 342) and the exciter (442) comprise an inductor (242A, 342A, 442A) in the form of a permanent magnet rotor.

9. An aircraft turbomachine propeller according to claim 3 or claim 6, further comprising a rotating non-contact sensor (248, 348, 448) mounted between the fixed shaft (238, 338, 438) and the main shaft (216, 316, 416) for delivering a current or voltage measurement to the control module.

10. Aircraft turbomachine propeller according to any one of claims 1 to 9, in which the multiplier is a rotation direction reversing multiplier (234, 334, 434).

11. Aircraft turbomachine comprising a propeller according to any one of claims 1 to 10.

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