Aircraft turbomachine fuel supply system

Abstract

The invention relates to a turbomachine fuel supply system (1), comprising: - a main circuit (12) for supplying fuel to a turbomachine combustion chamber, including a pressurization member (4) for delivering pressurized fuel into the main circuit (12) and having a maximum output power, and a fuel metering device (6) for regulating the fuel flow circulating in the main circuit (12), - an electrical power supply means for supplying power to the pressurization member (4) with a controllable power supply, - a saturation means (15) configured to limit the output power of the pressurization member (4) to a predetermined saturation power, which is less than or equal to the maximum output power of the pressurization member (4).whereby the rotational speed of a turbomachine equipped with the power supply system is limited to an overspeed value. See Figure 1 for the abbreviated version.

Description

Title of the invention: Fuel supply system for aircraft turbomachinery. Field of the invention

[0001] The present invention relates to the field of aeronautics, and more specifically, to aircraft turbomachinery.

[0002] More particularly, the invention relates to a fuel supply system for an aircraft turbomachine.

[0003] The invention also relates to a turbomachine comprising such a system, and an aircraft comprising such a turbomachine. Prior art

[0004] Fuel supply systems for aircraft turbomachinery are known from upstream to downstream in the direction of fuel flow in the system, comprising a fuel tank, at least one fuel pressurization device, a fuel metering device, and fuel injectors opening into a combustion chamber of the turbomachine.

[0005] At least one pressurization unit may be formed by at least one pump, and the system may for example include a first pressurization unit which is a low pressure pump and a second pressurization unit which is a high pressure pump, and which are connected to each other in series by a fuel line.

[0006] At least one pressurization device delivers fuel into the main circuit at a predetermined outlet pressure, so as to inject fuel into the combustion chamber at a pressure higher than the pressure prevailing in the combustion chamber. For this purpose, in known systems, at least one pressurization device is driven directly by a drive shaft of the turbomachine; that is, the rotational speed of the pump is dependent on the rotational speed of the turbomachine.

[0007] The fuel metering device allows the flow of fuel injected into the combustion chamber to be regulated, according to the desired operating regime of the turbomachine.

[0008] The fuel metering unit, also called FMU for "Fuel Metering Unit" in English terminology, conventionally comprises a metering valve, called FMV for "Fuel Metering Valve" in English terminology, controlled by a pilot current from an engine control unit, called ECU for "Engine Control Unit" in English terminology, of the turbomachine, which may itself be part of a system of full authority electronic regulation, known as FADEC for "Full Authority Digital Engine Control" in English terminology, of the turbomachine.

[0009] Patent application FR 2989735 Al of applicant Safran Aircraft Engines describes a system for controlling the opening position of such a fuel metering device.

[0010] However, it is known that failures can occur in the control of the fuel metering device, and in particular in the pilot current of the metering valve.

[0011] Such a malfunction can, in particular, cause the metering valve to open to a maximum passage area, allowing a high fuel injection rate into the combustion chamber. Injecting a significant quantity of fuel into the combustion chamber results in an increase in engine speed, i.e., the rotational speed of the turbomachine.

[0012] Such a situation, which can occur suddenly, leads to an overspeed phenomenon of the turbomachine, which represents a significant risk of deterioration of the turbomachine.

[0013] A known solution involves integrating a shut-off valve, also called an HPSOV (High Pressure Shut Off Valve), into the main circuit, for example between the fuel metering unit and the injectors, along with one or more sensors to detect overspeed, such as turbomachine speed sensors. When overspeed is detected, the shut-off valve closes to interrupt the fuel supply to the turbomachine.

[0014] However, this solution is implemented once the overspeed phenomenon has already occurred, in order to avoid exceeding the rotor speed limit, which could lead to the bursting of certain parts and the subsequent ejection of high-energy debris. Ideally, it would be preferable to prevent such an overspeed phenomenon from occurring in a turbomachine. Description of the invention

[0015] The present invention aims to remedy all or part of the disadvantages of the prior art mentioned above.

[0016] The invention relates, according to a first aspect, to a fuel supply system for an aircraft turbomachine, comprising: - a main circuit for supplying fuel to a turbomachine combustion chamber, the main circuit comprising a pressurizing device configured to deliver pressurized fuel into the main circuit and having a maximum output power Ppjnax, and a fuel metering device arranged downstream of the pressurizing device, configured to regulate a fuel flow circulating in the main circuit, - a means of supplying electrical power, configured to supply power to the pressurization unit with a controllable supply power P^j^, the power supply system further comprising: - a saturation means configured to limit an output power Pp of the pressurizing device to a predetermined saturation power PprSat, which is less than or equal to the maximum output power Ppjnax of the pressurizing device, whereby a rotational speed of a turbomachine equipped with the feed system is limited to an overspeed value.

[0017] In the power supply system, the saturation means makes it possible to limit the output power Pp, and in particular a nominal output power, of the pressurizing element so that it is saturated, or limited, to a saturation power value PpiSat less than or equal to its maximum output power Pp,maximale-

[0018] The maximum output power Ppjnax of the pressurizing device corresponds to a maximum output power that the pressurizing device can provide while maintaining its physical integrity.

[0019] The pressurizing device can thus provide an output power Pp between 0 and Pp sat continuously during nominal operation of the device, i.e. at a maximum level continuously under normal conditions without causing damage or exceeding the operating specifications of the pressurizing device.

[0020] The output power Pp of the pressurizing device is defined by the product of the fuel pressure and the fuel flow rate, at the outlet of the pressurizing device.

[0021] In other words, at constant flow rate, the saturation of the output power Pp of the pressurizing device corresponds to a saturation of the output pressure of the pressurizing device.

[0022] In prior art fuel systems lacking a saturation means, in the event of a malfunction of the fuel metering device resulting in its maximum opening, the power supplied by the pressurization device increases sharply to compensate for the drop in pressure differential between the pressurization device and the combustion chamber, caused by the abrupt increase in the flow rate through the metering device. However, this increase in the quantity of fuel delivered to the combustion chamber leads to an increase in engine speed and therefore in pressure within it, causing the pressurization device to supply an even higher outlet pressure, which in turn leads to an increase in engine speed and so on, leading to an overspeed of the turbomachine.

[0023] The saturation device, by limiting the output power of the pressurizing element, prevents the occurrence of overspeed by limiting the saturation device's capacity to maintain the aforementioned pressure differential. However, when this pressure differential decreases, the flow rate through the metering device also decreases, this flow rate being dependent, in particular, on the pressure difference across the device. This results in a decrease in the amount of fuel injected into the combustion chamber, and therefore a decrease in engine speed.

[0024] In other words, the saturation means makes it possible to avoid the very occurrence of the overspeed phenomenon in a turbomachine.

[0025] In other words, a rotational speed N of a turbomachine equipped with the power supply system is asymptotically limited to an overspeed value Noverspeed. In other words, the rotational speed N can approach an overspeed value, while remaining strictly below this value Noverspeed.

[0026] It follows that the fuel system may in particular not use a shut-off valve for managing an overspeed case, or any other equivalent means of cutting off the fuel supply when an overspeed initiation occurs.

[0027] Such a limitation of the output power of the pressurization device is also made possible by its electrical power supply delivering a controllable power supply, i.e. in particular independent of a rotation speed of the turbomachine, making it possible to decouple the output power of the pressurization device from the operating regime of the turbomachine, unlike a power supply by a drive shaft of the turbomachine for example.

[0028] It should be specified that the value of the saturation power Pp / Sat can be fixed, or variable, for example according to an operating point of the turbomachine, and that its value can more generally be within an interval [0; Ppjnax]-

[0029] Preferably, the saturation power PpjSat is strictly less than the maximum output power Ppjnax-

[0030] Other preferential, particularly convenient and advantageous features of the power supply system are described below.

[0031] - The electrical power supply means may include a module power supply to provide electricity to the pressurization unit and a control device to control the supply power P delivered by the power supply module to the pressurizing device, and the saturation means can be configured to limit the supply power P to a predefined saturation power Psat, which is less than a maximum supply power Pmax that the power supply module is configured to deliver to the pressurizing device to provide its maximum output power Pax.

[0032] The saturation of the output power of the pressurizing device is here achieved by the saturation of the supply power, i.e. input, of the pressurizing device.

[0033] Saturating the supply power Pgj^ to a predefined saturation power Palim sat allows the output power Pp of the pressurization device to be saturated, which has an efficiency ^lp such that the output power Pp is directly related to the supply power P

[0034] - The saturation means can be located in the power supply module and / or in the control body.

[0035] - The saturation means may be located in the power supply module, and The saturation method is a current limiter.

[0036] A current limiter type device allows the energy supply to be limited or capped in the event of exceeding the saturation power Pa;7rn saP while maintaining the supply.

[0037] - The saturation means can be a circuit breaker type device.

[0038] A circuit breaker-type device cuts off the power supply to the pressurizing unit in the event of an overload of the saturation power p alini, sat-

[0039] The circuit breaker-type device can be reset and the power supply restored when the supply power falls below the saturation power alini, sat-

[0040] - The saturation means can be located in the control organ, and the organ of control can be configured to limit the power supply P supplied to the pressurizing device by the power supply module to the saturation power Pan^^.

[0041] The saturation means is here formed by a particular configuration of the control element, which is configured so as to limit the supply power PaPin-

[0042] Preferably, the control unit is configured to execute a line of instructions limiting the supply power PaPm-

[0043] - The control unit can be configured to store a set of values ​​of saturation power each associated with a point in the flight domain of the turbomachine, and to limit the supply power P to a saturation power value which is selected by the control unit from said set of values ​​according to the point in the current flight domain of the turbomachine.

[0044] The saturation means here makes it possible to take into account in particular the point of flight of an aircraft comprising the system, and to select an appropriate saturation power.

[0045] - The saturation means can be located in the pressurization member and is configured to limit the output power Pp to the said saturation power Pp.sat regardless of the supply power P^^j absorbed by the pressurizing device.

[0046] The saturation means is here formed directly in the pressurization member, for example by a particular design of the pressurization member.

[0047] - The pressurization unit may include a high volumetric pump pressure.

[0048] The invention also relates, according to a second aspect, to a turbomachine comprising a fuel supply system as described above.

[0049] The invention also relates, according to a third aspect, to an aircraft comprising at least one turbomachine as described above. Brief description of the figures

[0050] The invention will be better understood, and other details, advantages and features thereof will become apparent from the following description, given by way of non-limiting example and with reference to the accompanying drawings, in which: • [Fig.1] is a schematic representation of a fuel supply system according to a first embodiment; • [Fig.2] is a schematic representation of a fuel supply system according to a second embodiment; • [Fig.3] is a schematic representation of a fuel supply system according to a third embodiment; • [Fig.4] is a schematic representation of a fuel supply system according to a fourth embodiment; • Fig. 5 represents several time evolution graphs of operational variables of the fuel supply system according to the invention, in comparison with a fuel supply system according to the prior art.

[0051] Detailed description of preferred embodiments

[0052] The present description is given by way of non-limiting agreement, each feature of an embodiment being able to be advantageously combined with any other feature of any other embodiment, according to any technically functional combination.

[0053] It should be noted from the outset that the figures are not necessarily to scale.

[0054] Figures 1 to 4 schematically represent a fuel supply system 1 for an aircraft turbomachine.

[0055] The power supply system 1 here comprises an upstream circuit 11 and a main circuit 12.

[0056] The "upstream" and "downstream" directions are defined in this document with respect to the general direction of flow of the fluid, i.e. of the fuel, in the main circuit 12.

[0057] The upstream circuit 11 includes a low-pressure pump 2.

[0058] The main circuit 12 includes a fuel metering device 6 and a pressurizing device 4, in particular high pressure, arranged between the low pressure pump 2 and the metering device 6.

[0059] The pressurization unit 4 may, for example, comprise a high-pressure positive displacement pump, for example, with a fixed displacement. As an alternative to a positive displacement pump, a centrifugal pump is also possible for the pressurization unit 4. The invention is not limited to a particular pumping technology, and any pumping means for delivering pressurized fuel may be considered.

[0060] The low pressure pump 2 can be a centrifugal pump, configured to pressurize the fuel supplying the pressurization member 4, for example from a fuel tank 17, so as to limit the risks of cavitation in the pressurization member 4.

[0061] The main circuit 12 supplies fuel to injectors 16 which are configured to inject fuel into a combustion chamber of the turbomachine.

[0062] The main circuit 12 may optionally include a shut-off valve 9, or stop valve, and possibly a flow meter 10, for example between the metering unit 6 and the injectors 16.

[0063] The turbomachine includes an electronic control system 3, for example a system known as FADEC, for "Full Authority Digital Engine Control". This electronic control system 3 may itself include an engine control unit, known as ECU for "Engine Control Unit".

[0064] The power supply system 1 also includes a control element 5 of the pressurization element 4.

[0065] The supply system 1 further includes a control unit 7 for the metering unit, which can be integrated into the electronic control system 3, to regulate the flow of fuel circulating through it.

[0066] The control member 5 and the control unit 7 receive orders from the electronic control system 3, respectively for controlling an output pressure of the pressurizing member 4 and for controlling an opening of the metering device 6.

[0067] The general structure of such a power supply system is described in particular in patent application FR 3068114 Al of the applicant Safran Aircraft Engines.

[0068] Other feeding systems exist, including, for example, pressurization devices such as metering pumps, particularly variable displacement pumps, thus eliminating the need for a metering unit. However, these systems are quite different and fall outside the scope of the present invention.

[0069] In the supply system 1 according to the present invention, the pressurization member 4, which includes in particular a high-pressure volumetric pump, is actuated by an actuator, in particular an electric one.

[0070] The electric actuator is preferably a variable-speed rotary electric motor. The motor's rotational speed is controlled by the control unit 5, thus allowing variation of the flow rate and outlet pressure of the pressurizing unit 4, particularly if the unit 4 is a positive displacement pump, and therefore a differential pressure across the metering valve 6 and an outlet flow rate downstream of the metering valve depending on its opening. Conventionally, a fuel recirculation line can be provided to reinject upstream of the unit 4 any excess fuel flow taken from the section of the circuit 12 between the unit 4 and the metering valve 6.

[0071] The pressurization unit 4 is therefore driven here independently of a drive shaft of the turbomachine or of any element of the turbomachine whose rotational speed depends on a rotational speed of the turbomachine.

[0072] In other words, the rotational speed with which the pressurization member 4 is driven is independent of a rotational speed of the turbomachine.

[0073] The power supply system 1 here includes an electrical power supply module 13 which is configured to supply electricity to the pressurization unit 4. The electrical power supply module 13 can itself draw electrical energy from an on-board electrical network of an aircraft on which the turbomachine is mounted, or from any other source of electrical energy on-board in the turbomachine (denoted E in Figures 1 to 4).

[0074] The power supply module 13 is connected to the control unit 5, which is configured to control the power supplied by the power supply module 13 to the pressurization unit 4.

[0075] The control unit 5 and the power supply module 13 are here part of an electrical power supply means, which makes it possible to supply the pressurizing unit with a supply power P that is controllable independently of the rotational speed of the turbomachine

[0076] The pressurization member 4 has a maximum output power Ppjnax, that is to say a maximum power with which fuel can be delivered into the main circuit 12 at the outlet of the member.

[0077] The output power Pp of the pressurizing device depends directly on the supply power Papm of the pressurizing device 4, which is here an electrical supply power P^pn of the pressurizing device 4 provided by the power supply module 13 and controlled by the control device 5.

[0078] The pressurization device 4 has an efficiency ^Ip which is defined by the ratio between the output power and the input power, that is to say here by the ratio between the output power Pp and the input power Papnr, i.e., _ Pp . lP~ Palim

[0079] The yield ^lp is classically between 0.1 and 1.

[0080] The maximum output power Pp^ax is thus delivered by the pressurization element 4 when it is supplied with a maximum supply power Palimpiax ■

[0081] The maximum supply power Papm is classically between 20 and 200 kW (kilowatts).

[0082] The power supply system 1 further includes a saturation means 15, which is configured to saturate the output power Pp of the pressurizing device to a power that is less than or equal to a predefined saturation power Pp^at.

[0083] The saturation power Pp^at is itself less than or equal to the maximum output power Ppjnax of the pressurization member 4.

[0084] In other words, in the supply system 1, the pressurization device 4 is configured to deliver an output power Pp from 0 up to the saturation power PpfSa^ according to the needs of the turbomachine, without however exceeding the saturation power PpiSah even though the pressurization device 4 is structurally and functionally capable of providing up to an output power Ppjnax greater than or equal to the saturation power Pp^at, under normal operating conditions of the pressurization device 4.

[0085] The saturation of the output power Pp of the pressurizing element 4 results in the saturation of the maximum fuel pressure that the pressurizing element 4 can deliver in the main circuit 12, which in turn results in the limitation of the pressure differential across the terminals of the metering device 6 and therefore of the flow circulating through it.

[0086] It follows that the supply system 1 is capable of limiting an uncontrolled increase in the engine speed of the turbomachine in the event of failure of the regulation system, in particular in the event of loss of control of the opening of the metering valve 6 and even if this opening of the metering valve suddenly becomes maximum, and therefore makes it possible to avoid the subsequent occurrence of an overspeed phenomenon of the turbomachine.

[0087] In this document, "saturation" of power means a limitation of power to a maximum (in absolute value) of power.

[0088] Power saturation can take the form of power limiting, meaning that the pressurization device 4 does not deliver power exceeding the saturation power PpSab, regardless of the power absorbed and / or the power command received. In other words, power saturation can be a power limitation to a maximum power threshold.

[0089] Power saturation can also take the form of a power cut-off, i.e., the pressurization device 4 is no longer supplied with power as soon as its output power Pp exceeds the saturation power Pp,sat-

[0090] Power saturation can be fixed, i.e. predefined, or variable, i.e. present a maximum and / or minimum power plateau that varies according to the operating conditions of the power supply system 1.

[0091] Power saturation may, for example, depend on the domain or point of flight of an aircraft (including in particular its flight altitude, and / or its speed or "mach", and / or the surrounding temperature).

[0092] In a first preferred embodiment, illustrated in [Fig.1], power saturation is achieved directly at the power supply module 13.

[0093] The saturation means 15 is located in the power supply module 13, and is configured to limit the supply power P provided to the pressurization member 4 to a predefined saturation supply power P^^sat.

[0094] It follows that the output power Pp of the pressurization element 4 is also limited to a saturation power PPiSab which depends directly on the saturation supply power Palim,sat-

[0095] The saturation supply power Psaj is in particular less than a maximum supply power Pajnn inax that the power supply module 13 is capable of delivering to the pressurizing device to provide a maximum output power Ppjnax-

[0096] Of course, the control member 5 can control the power supplied to the pressurization member 4 so as to provide any necessary power supply, in particular less than the saturation power supply Palimsat' within the limit of the saturation power supply P alîm sat-

[0097] The saturation means 15 can for example be a current limiter, parameterized so that the power supply module can provide the maximum predefined Palimsat saturation supply power.

[0098] In this example, power saturation takes the form of power limiting, that is to say, for any command from the electronic control system 3 which orders the supply of a power supply greater than the saturation power supply Palimsat to the pressurizing device 4, the power supplied to the pressurizing device 4 corresponds to the saturation power supply Passât-

[0099] In this example, the outlet pressure, denoted Pp, delivered by the pressurization device 4 in the main circuit 12 is limited by the saturation supply power Pp. It also depends on the flow rate passing through the pressurization device 4, which corresponds to the flow rate passing through the metering device 6, denoted QPMV-

[0100] The maximum outlet pressure Pp, corresponding to a saturation pressure Pp sat', is defined by: . ^aUm,sat . Pp, sat “ Qp^Hp

[0101] In a second embodiment, illustrated in [Fig.2], power saturation is achieved at the control element 5.

[0102] The saturation means 15 is formed by the control member 5, which is configured so as to limit the supply power Paiim supplied to the pressurization member 4 by the power supply module 13 to a predefined saturation supply power Palimsat.

[0103] It follows here also that the output power Pp of the pressurization element 4 is limited to a saturation power Pp:Sab, which depends directly on the saturation supply power Palimsat-

[0104] Of course, the control member 5 can control the power supplied to the pressurizing member 4 so as to provide any power supply necessary, in particular lower than the saturation power supply Palim,sat' within the limit of the saturation power supply P aHmiSat-

[0105] The saturation means 15 is for example formed by the configuration of the operating instructions of the control unit 5 so that the supply power P alim is limited to the saturation supply power Palimsat' 9ueUe that s°it the power supplied by the power supply module 13 and whatever the order received by the electronic control system 3.

[0106] By way of example, the operating instructions stored and executed by the control unit 5 may include an instruction line checking the value of the power supplied to the pressurizing unit 4, and regulating the supply current and / or voltage to provide a power not exceeding the saturation supply power PaijD1Sat^ when the power value reaches or exceeds the saturation supply power P alîmsat-

[0107] In this example, the saturation supply power PaHniiSat can be a fixed, predefined value stored in a non-volatile storage memory of the control unit 5.

[0108] The saturation power supply Panm sat can also be selected from a set of saturation power values, the set of values ​​being stored in a non-volatile storage memory of the control unit 5. In this set of values, the saturation power values ​​are each associated with a point in the flight domain of the turbomachine. The supply power Pgj^ is then limited to a saturation power supply P alîmsat corresponding to the current point in the flight domain of the turbomachine. This makes it possible to optimize protection against the occurrence of overspeed while taking into account, in particular, the requirements of the turbomachine in transient operating regimes and / or taking into account the current point in the flight domain, including in particular the flight altitude of the aircraft, and / or its flight speed or "Mach", and / or the ambient temperature.

[0109] In a third embodiment, illustrated in [Fig.3], the saturation means 15 is formed by a circuit breaker type device, which can be located on the power supply module 13 and / or in the control unit 5.

[0110] The circuit breaker-type device is configured to cut off the electrical power supplied to the pressurizing unit 4 when the electrical power supply reaches or exceeds the saturation power supply PaUm^at-

[0111] In this embodiment, power saturation is a cutoff of the supply power when it exceeds the saturation supply power Pan^at-

[0112] The circuit breaker-type device can be reset, preferably automatically, when the supply power again becomes equal to or less than the saturation supply power Pai!msat-

[0113] In a fourth embodiment, illustrated in [Fig.4], the saturation means 15 is formed at the pressurization member 4.

[0114] As mentioned above, the pressurization unit 4 may include a pump comprising a pump turbine, driven by the electric actuator.

[0115] The saturation means 15 may, for example, be located between the electric actuator and the pump turbine, and comprise a mechanical element configured to mechanically limit the output power of the pressurization element, i.e., at the outlet of the pump turbine, to the saturation power Pp^at-

[0116] For example, the pressurization device 4 may include a geometry and / or arrangement of its components such that the efficiency of the pressurization device drops significantly as soon as the Papin supply power exceeds the Papmsat saturation supply power.

[0117] It is specified that the first to fourth embodiment described above are freely combinable, so that the saturation module 15 can be located in the power supply module 13, and / or in the control member 5, and / or in the pressurization member 4. This makes it possible in particular to produce redundancies in the saturation of the output power.

[0118] The operation of the feed system 1 is described with reference to Figure 5, which shows time-evolution graphs of the pilot current ip^y of the metering valve 6, the flow area SpMy of the metering valve 6, the outlet pressure Pp of the pressurizing device 4, and the pressure Pc in the combustion chamber, as well as the differential pressure Ap, the flow rate Q through the main circuit 12, and the rotational speed N of the turbomachine. In the graphs of [Fig. 5], the solid lines illustrate the operation of the feed system 1 equipped with a saturation means 15, while the dashed lines illustrate the operation of a conventional feed system without such a saturation means.

[0119] In the context of a normally functional operation of the feed system 1, the metering unit 6 is controlled by the electronic control system 3 according to the desired operating regime of the turbomachine, as illustrated in the time period Tl on the graphs of [Fig.5].

[0120] In particular, the metering device 6 receives a pilot current ip^y which allows the latter to be opened or closed so as to vary the Sp^y passage section of the metering device 6 and thus vary the flow rate Q passing through the metering device 6.

[0121] For example, when the operating speed needs to be increased, the metering valve 6 is opened in a controlled manner so as to increase the flow rate Q passing through it, and inject more fuel into the combustion chamber. This results in an increase in the pressure Pc in the combustion chamber, and the outlet pressure Pp delivered by the pressurization device 4 also increases, in order to maintain a sufficient positive pressure differential Ap between the pressurization device 4 and the combustion chamber.

[0122] In the event of a malfunction of the supply system 1, as illustrated in the time period T2 on the graphs of figure 5, it is possible that the metering device 6 is no longer correctly controlled by the electronic control system 3. In particular, it is possible that an error in the pilot current iFM causes the metering device 6 to open abruptly to its maximum opening SpMy = Sniax^ i.e. that the passage area of ​​the metering device 6 is at its maximum.

[0123] In reaction to this maximum opening of the metering device 6, the pressure differential Ap between the pressurizing member 4 and the combustion chamber is also caused to drop abruptly, in response to which the pressurizing member 4 would classically be led to increase its outlet pressure Pp, which can go up to a maximum outlet pressure Pnlax delivered at the maximum power Pp^iax, in order to increase its outlet pressure to restore said pressure differential and to follow the rise in pressure in the combustion chamber following the abrupt increase in flow (see the dashed curves Pc and Pp in time period 3 on the graphs of [Fig.5]).

[0124] In the described fuel supply system 1, the outlet pressure Pp is limited to a saturation pressure Ppsat due to the limitation of the output power Pp to a saturation power Ppat. This has the effect of limiting the outlet pressure of the pressurization device 4, and therefore reducing the pressure differential between the pressurization device 4 and the combustion chamber. In particular, the pressurization device 4 does not reach the maximum outlet pressure Pmax. As a result, the flow rate Q in the main circuit 12, which depends on the opening of the metering valve 6 (which remains at its maximum here) and also on the pressure differential between the pressurization device 4 and the combustion chamber, stabilizes or decreases.This in turn leads to a decrease or limitation of the pressure Pc in the combustion chamber, and thus a decrease or limitation of the operating regime of the turbomachine, i.e. its rotational speed N which thus remains lower than a rotational speed Noverspeed resulting in the overspeed phenomenon (see the solid line curves in the time period T3 on the graphs of [Fig.5]).

[0125] The saturation means 15, which is configured to limit the output power Pp of the pressurizing element 4 to a saturation power Pp^at which is less than the maximum output power Ppjnax of the pressurizing element 4, in a supply system 1 in which the pressurizing element is supplied with energy by a dedicated supply means, i.e. in particular uncorrelated with the operating regime of the turbomachine, thus makes it possible to avoid the occurrence of any overspeed phenomenon of the turbomachine.

[0126] It is more generally recalled that the invention is not limited to the examples described and illustrated.

[0127] The invention is more broadly applicable to any fluid supply system and any type of fuel, whether intended for the fuel supply of a turbomachine or not.

[0128] The invention also relates to a turbomachine, comprising a power system as described above, and to an aircraft comprising at least one such turbomachine, and preferably between one and four such turbomachines.

Claims

Demands

1. Fuel supply system (1) for an aircraft turbomachine, comprising: - a main circuit (12) for supplying fuel to a turbomachine combustion chamber, the main circuit (12) having a pressurization member (4) configured to deliver pressurized fuel into the main circuit (12) and having a maximum output power Pp^ax^ and a fuel metering device (6) arranged downstream of the pressurization member (4), configured to regulate a fuel flow circulating in the main circuit (12), - an electrical power supply means, configured to supply power to the pressurization member (4) with a controllable supply power Pp, the supply system being characterized in that it further comprises: - a saturation means (15) configured to limit an output power Pp of the pressurization member (4) to a predetermined saturation power Pp)Sat,which is less than or equal to the maximum output power Ppjnax of the pressurizing device (4), whereby a rotational speed (N) of a turbomachine equipped with the feed system is limited to an overspeed value (N overspeed)',

2. Power supply system (1) according to claim 1, characterized in that the power supply means comprises a power supply module (13) for supplying power to the pressurizing device (4) and a control device (5) for controlling the power supply PJ delivered by the power supply module (13) to the pressurizing device (4), and in that the saturation means (15) is configured to limit the power supply PA to a predefined saturation power PA, which is less than a maximum power supply PA that the power supply module (13) is configured to deliver to the device pressurization (4) to provide its maximum output power P p,max-

3. Power supply system (1) according to claim 2, characterized in that the saturation means (15) is located in the power supply module (13) and / or in the control element (5).

4. Power supply system (1) according to claim 3, wherein the saturation means (15) is located in the power supply module (13), characterized in that the saturation means (15) is a current limiter.

5. Power supply system (1) according to any one of claims 3 or 4, characterized in that the saturation means is a circuit breaker type device.

6. Power supply system (1) according to any one of claims 3 to 5, wherein the saturation means (15) is located in the control member (5), characterized in that the control member (5) is configured to limit the power supply Palim supplied to the pressurization member (4) by the power supply module (13) to the saturation power Pa]1]n saf.

7. Power supply system (1) according to claim 6, characterized in that the control member (5) is configured to store a set of saturation power values ​​each associated with a point in the flight domain of the turbomachine, and to limit the supply power P^^ to a saturation power value which is selected by the control member (4) in said set of values ​​as a function of the point in the current flight domain of the turbomachine.

8. Power supply system (1) according to any one of claims 1 to 7, characterized in that the saturation means (15) is located in the pressurizing member (4) and is configured to limit the output power Pp to said saturation power Pp,sat regardless of the supply power Pgjj^ absorbed by the pressurizing member (4).

9. Feeding system (1) according to any one of claims 1 to 8, characterized in that the pressurization member (4) comprises a high-pressure volumetric pump.

10. Turbomachine comprising a fuel supply system according to any one of claims 1 to 9.

11. Aircraft comprising at least one turbomachine according to claim 10.