Search

EP-4735747-A1 - FUEL BOOST SYSTEM FOR A FUEL CIRCUIT

EP4735747A1EP 4735747 A1EP4735747 A1EP 4735747A1EP-4735747-A1

Abstract

The invention relates to a fuel boost system (1) for a fuel circuit, the system comprising: - a hydraulic subassembly (2) comprising a rotary part capable of circulating the fuel (C), which part is mounted in a first chamber (E1); - an electric motor (3) capable of driving the hydraulic subassembly (2); - a driven rotor (4) mechanically coupled to the rotary part of the hydraulic subassembly (2) and mounted in the first chamber (E1) and; - a driving rotor (6) mechanically coupled to a rotor of the electric motor (3) and mounted in a second chamber (E2), the driving rotor (6a) and the driven rotor (4a) being magnetically coupled.

Inventors

  • MIGLIORERO, Vincent
  • VOZY, Thibaut
  • EPALLE, Patrick
  • MASSON, BRUNO

Assignees

  • Safran Aerosystems

Dates

Publication Date
20260506
Application Date
20240611

Claims (10)

  1. Fuel feeding system (1) for a fuel circuit (C) of an aircraft turbomachine, comprising: a hydraulic subassembly (2) comprising a rotating part (21), capable of generating a circulation of the fuel (C), mounted in a first enclosure (E1), and an electric motor (3), capable of driving the hydraulic subassembly (2) and supplied with high direct or alternating voltage, a driven rotor (4) mechanically coupled to the rotating part (21) of the hydraulic subassembly (2) and mounted in the first enclosure (E1), and a driving rotor (6) mechanically coupled to a rotor (31) of the electric motor (3) and mounted in a second enclosure (E2), the driving rotor (6) and the driven rotor (4) being magnetically coupled, the second enclosure (E2) being sealed against the fuel (C) and defining a pressurized cavity.
  2. Fuel feeding system (1) according to claim 1, in which an internal wall (5) impervious to the fuel (C) is interposed between the driving rotor (6) and the driven rotor (4), in particular common to the first enclosure (E1) and to the second enclosure (E2).
  3. Fuel feeding system (1) according to claim 2, wherein: the hydraulic subassembly (2) comprises a pump body (20) surrounding the rotating part (21), the internal wall (5) being fixed in a sealed manner to the pump body (20) so as to form the first enclosure (E1), and/or the electric motor (3) comprises a motor wall (30) surrounding the rotor (31) and a stator (32) of the electric motor (3), the motor wall (30) being fixed in a sealed manner to the first enclosure (E1) so as to form the second enclosure (E2).
  4. Fuel feeding system (1) according to claim 2, wherein: the hydraulic subassembly (2) extends in a housing (11), the internal wall (5) being fixed in a sealed manner to the housing (11) so as to form the first enclosure (E1), and/or the electric motor (3) extends into a cartridge (10), the cartridge (10) being fixed in a sealed manner to the first enclosure (E1) so as to form the second enclosure (E2).
  5. Fuel feeding system (1) according to any one of the preceding claims, wherein the electric motor (3) is electrically supplied with a direct voltage greater than 320VDC or an alternating voltage greater than 203VAC.
  6. Fuel feeding system (1) according to any one of the preceding claims, wherein the second enclosure (E2) is explosion-proof.
  7. Fuel feeding system (1) according to any one of the preceding claims, in which the second enclosure (E2) is fixed against the first enclosure (E1), in particular by removable fixing members (7, 8).
  8. Fuel feeding system (1) according to claim 7, in which the fixing members (8) are associated with at least one seal.
  9. Aircraft turbomachine comprising a fuel circuit (C) comprising a fuel boosting system (1) according to one of the preceding claims.
  10. Method of using an aircraft turbomachine in flight according to claim 9, in which the rotor (31) of the electric motor (3) of the fuel supply system (1) drives, from the second enclosure (E2) defining a pressurized cavity, the rotating part (21) of the hydraulic subassembly (2) via the driving rotor (6) and the driven rotor (4) magnetically coupled.

Description

Fuel feeding system for a fuel circuit The present invention relates to the field of fuel supply systems for a fuel circuit, in particular for an aircraft turbomachine. In a known manner, an aircraft comprises one or more turbomachines comprising a combustion chamber into which air and fuel enter, configured to react together following a combustion reaction, so as to release the energy necessary for the thrust of the aircraft. The air comes from outside the turbomachine and is guided towards the combustion chamber by an air stream. The fuel comes from a fuel circuit opening into the combustion chamber. The fuel circuit can traditionally include, in particular depending on the direction of fuel flow: one or more fuel storage tanks, a fuel pump, a filter for retaining solid particles contained in the fuel, a mechanical pump, a metering valve for a mass flow of fuel and one or more injectors to spray the mass flow into the combustion chamber. If there are multiple fuel storage tanks, one or more transfer pumps are additionally used to transfer fuel between the fuel storage tanks. Particularly known are fuel and transfer pumps, known as "submersible motor" pumps, in which an electric drive motor is immersed in the fuel, to ensure cooling of the electric motor and lubrication of the rotating guide bearings of the rotor of the electric motor. The electric motor is said to be "submerged" in that the fuel circulates in the cavity of the motor in contact with the rotor and the stator. The electric motor is typically an asynchronous motor connected directly to the aircraft's AC electrical network, with a voltage of 115VAC, an acronym for "Volts Alternating Current" in English, or a permanent magnet synchronous motor controlled by an electronic control unit, also known as "ECU" for "Electronic Command Unit (ECU)" in English, supplied with a DC voltage typically of 270VDC, an acronym for "Volts Direct Current" in English, or an AC voltage of 115VAC. One of the current challenges for reducing fuel consumption in aircraft is to reduce the on-board mass of aircraft, particularly that of wiring. One possibility for reducing the cross-section of wiring while maintaining electrical power is to work with higher voltages, typically a direct voltage of 540VDC or more, or an alternating voltage of 230VAC or more. Such voltages associated with traditional construction methods of wound motors have the disadvantage of causing partial discharges, namely the appearance of a partial short circuit within the cavities present in the insulators between two electrical conductors due to the presence of a strong local electric field ionizing the conductive gas. Such partial discharges can in the long term deteriorate the insulators between the electrical conductors and ultimately lead to electric arcs. In submersible pump designs, such partial discharges, in contact with fuel vapors, are likely to cause a risk of ignition and/or explosion. Such a risk is increased by the fact that submersible pumps are in a non-pressurized area, whose pressure can vary from approximately 1013HPa on the ground to approximately 100HPa at 16km altitude in flight. Low pressures are more likely to cause partial discharges according to Paschen's law. In fact, a decrease in pressure lowers the voltage at which partial discharges occur. To protect against this, according to the CS 25.981 standard, it is known to add a set of protective barriers in the architectures of submersible motor pumps to make the presence of ignition sources extremely unlikely, in particular that it does not result from a simple failure. The rotor and the stator are, for example, covered with one or more layers of electrically insulating coating, such as an overmolding and an impregnation resin. The body in which the motor is mounted is also explosion-proof. However, such barriers are likely to be insufficient to demonstrate that the risks of ignition remain extremely improbable in the context of high voltage power supply, because these would not be independent of the degradation linked to partial discharges. In this context, the invention aims to maintain a level of safety in accordance with standard CS 25.981, when the motor of the aircraft electric motor pump is supplied with voltages likely to cause partial discharges, in particular intended to be supplied by high voltages. In the case of pumps with electric motors powered by low voltages, it is known from application BE1028023A1 to drive the motor by magnetic coupling and to offset it axially relative to the pump to make the size of the pump independent of that of the motor. A magnetic coupling is also taught by US20040109773A1 and US20150267704A1 in automotive and underwater fuel pumps respectively, which are not exposed to low pressures at high altitude. None of these architectures is exposed to the risk of occurrence of partial discharges and adapted to deal with it. Another disadvantage of fuel booster and transfer pumps is related