System for supplying fuel to turbine engine

Abstract

The invention relates to a system for supplying fuel to a turbine engine (100), the system comprising a fuel circuit (102) comprising at least:-a counter-rotating centrifugal pump (200) comprising at least one outer impeller (2021) and at least one central impeller (2022) having opposite directions of rotation; -a turbomechanical unit (204) configured to control at least one outlet of fuel to the combustion chamber (108); the system is configured to adjust the flow of fuel to the combustion chamber (108) based on a flow setpoint (Pc) in the hydraulic circuit downstream of the turbomechanical unit by varying the rotational speed of the center impeller based on the evaluated pressure drop (P2) or based on the evaluated pressure difference (P1) to adapt the pressure supplied by the pump to a demand associated with the flow setpoint.

Description

Technical Field

[0001] This invention relates to the field of turbine engines. More specifically, it relates to a fuel supply system, a turbine engine including the supply system, and a method for regulating the fuel flow rate in the system. Background Technology

[0002] Existing technologies include documents FR-A1-3 078 551, EP-B1-3 077 681, and EP-B1-0 474 585.

[0003] The turbine engine mounted on the aircraft is equipped with a fuel supply circuit 102, which delivers fuel to the combustion chamber, which must be adjusted as needed according to flight conditions. (See reference...) Figure 1 The fuel supply circuit 102 typically includes a positive displacement high-pressure main pump 200, which delivers fuel toward the hydromechanical unit 204 before fuel is injected into the combustion chamber 108. This assembly is designed to ensure that the fuel flow toward the combustion chamber is regulated to the demand. The control room 222 typically controls the hydromechanical unit 204 such that the hydromechanical unit adapts the flow rate delivered by the pump 200 to the demand of the combustion chamber 108.

[0004] Typically, pump 200 is driven by the output shaft 106 of the accessory gearbox 104 of the turbine engine, and the output shaft itself is driven by the motor shaft of the main body of the turbine engine. Figure 1 (Not shown in the diagram) Driven. A transmission device 220 is typically mounted between the shaft of the accessory gearbox 104 and the pump 200 to adapt the rotational speeds between these two devices. This device determines the ratio K between the speed of the pump 200 and the rotational speed ω of the turbine engine's motor shaft. This device also typically drives the device 216 for supplying fuel to the circuit 102 from the fuel reservoir R. The linear characteristic Cyl of the fuel flow rate of the pump 200 and the pump's drive speed depends particularly on the pump's displacement. The pump 200 must be sized such that the displacement, and therefore the speed of the output shaft of the accessory gearbox 104 (whether low or high), enables the delivery of the flow rate required for all operating speeds of the turbine engine.

[0005] like Figure 2 You can see (in) Figure 2 It shows the variation of flow rate F as a function of the rotational speed ω of the turbine engine's motor shaft, and the nonlinear variation of fuel demand F1 as a function of the turbine engine's speed. The rotational speed ω of the turbine engine's motor shaft varies between a minimum value ωmin for turbine engine ignition and a maximum value ωmax for takeoff. The speed corresponding to cruise flight lies between these two extreme values.

[0006] Depending on the application, the key is either low-speed ignition or high-speed takeoff. Figure 2 In this critical point, located at the ignition point, the pump displacement must be selected such that the pump's linear characteristic equals the value Cyl1 to ensure sufficient flow under all flight conditions. This value Cyl1 may be significantly higher than the minimum value Cylmin required under some flight conditions (or even the value Cyl2 required during takeoff).

[0007] Based on this size design, the flow rate supplied by the pump therefore follows... Figure 2 The straight line L1 on the flow / rotation speed diagram. Therefore, during high drive speed phases (especially during cruise flight), the pump delivers a higher flow rate than required, and thus delivers excess fuel F2.

[0008] Therefore, the fluid machinery unit 204 must be routed via the recirculation loop B. rec This causes excess fuel F2, which is in excess of demand, to return to the pump.

[0009] like Figure 1 As shown, the problem of regulating fuel flow is further exacerbated when the fuel supply loop 102 is used to actuate the variable geometry 212 of the turbine engine. Actuation of the variable geometry 212 causes changes in fuel demand within the loop, affecting the size design of the pump 200, the operation of the fluid machinery unit 204, and the recirculation loop B. rec This must be taken into account in terms of its characteristics.

[0010] This fuel supply system architecture has several drawbacks. Excessive flow injected by pump 200 results in more energy being extracted from the accessory gearbox 104 than required, which negatively impacts the efficiency of the turbine engine. The excess mechanical energy is converted into energy in the recirculation loop B. res The heat energy dissipated in the fuel circuit must be discharged. This has a negative impact on the size and quality of the fuel circuit, especially on the heat exchanger (not shown) that is configured to discharge heat from the circuit.

[0011] Therefore, it may be desirable to provide a fuel supply system that avoids at least some of the problems and constraints mentioned above. Summary of the Invention

[0012] Therefore, a system for supplying fuel to a turbine engine is proposed, the turbine engine including at least one accessory gearbox, the accessory gearbox including at least one output shaft, the system including a fuel circuit, the fuel circuit including: - Output shaft of accessory gearbox; - Counter-rotating centrifugal pump, which includes at least two concentric impellers: At least one external impeller is configured to be driven to rotate in a first direction by the output shaft of the accessory gearbox of the turbine engine to deliver a certain flow rate of fuel into the circuit; At least one central impeller, the at least one central impeller being configured to rotate in a second direction opposite to a first direction of the outer impeller; A fluid machinery unit, configured to control at least one fuel outlet toward the combustion chamber; The system is configured to regulate the flow rate of fuel toward the combustion chamber based on a flow setpoint in the hydraulic circuit downstream of the fluid machinery unit, characterized in that: - The fluid machinery unit includes at least one measuring device, configured to assess a pressure difference based on the flow setpoint or to assess a pressure drop relative to the flow setpoint; and The system also includes a speed regulating device and at least one control unit. The speed regulating device is configured to control the rotational speed of the central impeller, and the at least one control unit is used to control the speed regulating device to change the rotational speed of the pump's central impeller according to an assessed pressure drop or an assessed pressure difference, so that the pressure supplied by the pump via the drive of the outer impeller is adapted to the demand associated with the flow setpoint.

[0013] The inventors have observed certain technical problems in some turbine engines when using hybrid power solutions (where the output shafts of an electric motor and an accessory gearbox of a turbine engine are combined to drive a positive displacement pump via a planetary gear system). These problems affect the lifespan of the positive displacement pump's bearings (at very low operating speeds) or cause significant variations in injection flow (at high power operating speeds) at both the very low operating speeds and the high power operating points. It has also been noted that solutions to overcome these constraints may involve increasing the pump's mass and overall size, as well as increasing the power of the electric motor.

[0014] The described solution also enables the speed of the equipment to be controlled by regulating the pressure drop at the valve port or by the pressure difference at the metering device port, allowing the pump to be driven at high speeds while maintaining efficiency compatible with the need to reduce thermal rejection. In particular, a recirculation loop is no longer necessary. The invention also saves energy and material resources by adapting to pressure requirements while avoiding oversized pump components to achieve maximum power.

[0015] The present invention may also include one or more of the following optional features in any technically possible combination: - The pump consists of two impellers (an outer impeller and an inner impeller), which can be mechanical or electric; - The pump includes at least one mechanical impeller and one electric impeller; -The electric impeller is a central impeller, and the speed regulation device is an electric motor; - The size of the central impeller is designed to supply approximately 25% of the total power required for the flow setpoint, and the size of the outer impeller is designed to supply approximately 75% of the total power. - The dimensions of the central impeller and the outer impeller are designed such that the rotational speed of the central impeller driven by the speed regulating device is + / -30% of the rotational speed of the outer impeller driven by the output shaft of the auxiliary gearbox of the turbine engine.

[0016] -The fluid machinery unit also includes at least: A metering device, configured to deliver a flow rate equal to the flow setpoint toward the fuel outlet; A servo valve is configured to receive a flow setpoint and control the position of the metering device. A regulating valve is located downstream of the metering device and configured to maintain a constant pressure differential at the port of the metering device. - Measuring equipment should include at least: A first pressure sensor is positioned at the port of the metering device to assess the pressure difference relative to the flow setpoint. The second pressure sensor is configured to evaluate the pressure drop at the port of the control valve, which corresponds to the change in pressure. - The circuit also includes: A supply device for supplying the circuit, driven by the output shaft of the accessory gearbox of the turbine engine or a speed regulating device; Variable geometry supply loop for turbine engines; A filter is connected at least to a supply unit, a variable geometry supply loop, and a pump to at least capture contaminants from the fuel.

[0017] The present invention also relates to a turbine engine comprising the system described above.

[0018] The present invention also relates to a method for regulating a centrifugal pump of a turbine engine as described above, the method executing a control rule for controlling the rotational speed of the impeller of the centrifugal pump, the control rule increasing or correspondingly decreasing the speed when the pressure difference or pressure drop decreases or increases, such that the flow rate and pressure at the outlet of the loop are adapted to the flight conditions of the aircraft.

[0019] The method may also include one or more of the following optional features in any technically feasible combination: - The control rules are configured to also adapt the pressure supplied by the pump and the pressure in the circuit to the operating conditions of the secondary supply circuit or variable geometry. - Control rules should include at least: Received flow setpoint; Evaluate the pressure difference relative to the flow setpoint or evaluate the pressure drop relative to the flow setpoint; The rotational speed of the pump's central impeller is changed based on the assessed pressure difference or the assessed pressure drop to adapt the pressure supplied by the pump to the flow setpoint requirements. Attached Figure Description

[0020] The invention will be better understood through the following description, given only by way of example and with reference to the accompanying drawings, in which: - Figure 1 The diagram schematically illustrates a fuel circuit according to the prior art. - Figure 2 A diagram showing rotational speed and flow rate is provided, illustrating the flow rate supplied by the fuel pump and, for example... Figure 1 The difference between the required flow rates of the loops shown; - Figure 3 A schematic half-section of a turbine engine from which the present invention can be used is shown; - Figure 4 A first embodiment of the fuel supply system according to the present invention is illustrated schematically. - Figure 5 An exploded view of a counter-rotating centrifugal pump that can be used with the present invention is shown; - Figure 6 The structure of the fluid machinery unit according to the present invention is shown very schematically; - Figure 7 A variation of a first embodiment of the fuel supply system according to the invention is shown very schematically; and - Figure 8 The steps in the control rules for controlling the pump according to the invention are shown very schematically. Detailed Implementation

[0021] The above has been described Figure 1 and Figure 2 .

[0022] Reference Figure 3 The present invention will describe a turbine engine 100 according to the present invention.

[0023] In this example, the turbine engine is a dual-flow turbine engine. The turbine engine 100 includes at least one fan 110, a low-pressure compressor 114 and a high-pressure compressor 118, a combustion chamber 108, a high-pressure turbine 120 and a low-pressure turbine 122.

[0024] The turbine engine also includes a motor shaft 116. Typically, the components of the high-pressure compressor 118 and the high-pressure turbine 120 rotate as units on the motor shaft 116 and together with the combustion chamber 108 form the motor portion of the turbine engine 100.

[0025] The turbine engine may also include an accessory gearbox 104 and a fuel supply circuit 102. The accessory gearbox 104 may include multiple gear trains connected to output shafts for driving various devices. Here, one of the output shafts, output shaft 106, is connected to the fuel supply circuit 102 for supplying the combustion chamber.

[0026] Typically, the accessory gearbox 104 serves as the connection between the motor shaft 116 and the starter / generator ( Figure 3 The connection between the starter / generator (not shown in the image) and the turbine engine 100 can be used to drive the turbine engine 100 during the start-up phase or to generate current when the turbine engine is ignited.

[0027] As previously mentioned, the turbine engine may also include variable geometry 212 ( Figure 3 (Not shown in the image), the variable geometry can be activated under certain operating conditions. These variable geometries 212 are, for example and in a non-limiting manner, variable pitch blades at the inlet of a high-pressure compressor.

[0028] Still refer to Figure 3 The airflow at the outlet of fan 110 is split into a main flow Q entering the motor and a secondary flow S surrounding the motor. Therefore, the main flow passes through the low-pressure compressor 114 and the high-pressure compressor 118, the combustion chamber 108 supplied by the aforementioned fuel supply circuit 102, and then through the high-pressure turbine 120 and the low-pressure turbine 122.

[0029] refer to Figure 4 The fuel supply system according to the present invention will be described.

[0030] The system includes a circuit 102. The circuit 102 includes at least the output shaft 106 of the accessory gearbox 104 of the turbine engine 100 described above.

[0031] and Figure 1Unlike the circuit described in the previous section, the circuit 102 of the present invention also includes a counter-rotating pump 200 and a fluid electrical unit 204. The counter-rotating pump is at least connected to the output shaft 106 of the accessory gearbox 104 of the turbine engine 100, and the fluid electrical unit is connected to the pump 200 and configured to control at least one fuel outlet toward the combustion chamber 108.

[0032] The counter-rotating centrifugal pump 200 includes at least a so-called first outer impeller 2021 and a so-called second central impeller 2022. The outer impeller 2021 and the inner impeller 2022 are concentric, for example... Figure 5 shown.

[0033] The outer impeller 2021 and the inner impeller 2022 can be mechanical or electric. Preferably, the pump 200 includes at least one mechanical impeller and at least one electric impeller. Preferably, the electric impeller is the central impeller 2022.

[0034] Pump 200 may also include at least one shaft 210 that carries at least one impeller, such as Figure 5 As shown. Shaft 210 is preferably coaxial with the drive shaft of the outer impeller 2021.

[0035] The outer impeller 2021 is configured to rotate in a first direction S1 driven by the output shaft of the accessory gearbox 104 of the turbine engine to deliver a certain flow rate of fuel to the supply circuit 102.

[0036] The pump also includes a volute 203 for conveying fuel through circuit 102. The volute 203 is the main body of the pump 200, serving as a pressure control vessel and guiding the fuel flow into and out of the pump 200. The volute 203 receives the fuel flow accelerated by the rotation of the outer impeller 2021 and / or the central impeller 2022, converting the kinetic energy of the fuel flow into pressure. Depending on sizing requirements, the cross-section of the volute 203 can be variable or constant.

[0037] The supply system also includes a speed regulating device 208 connected to the central impeller 2022 to drive the central impeller to rotate in a second direction S2 opposite to the direction of the outer impeller 2021. The electrical device or motor includes at least one motor shaft 207 for driving the central impeller 2022.

[0038] The speed regulating device 208 can be an electric, mechanical, or hydraulic system. Preferably, the device 208 is an electric motor.

[0039] The speed regulating device is configured to control the speed of the central impeller independently of the speed of the gearbox's output shaft.

[0040] In some embodiments, the connection between the outer impeller 2021 and the central impeller 2022 can also be reversed, i.e., the central impeller is driven by the output shaft 106 of the accessory gearbox 104, and the outer impeller is driven to rotate by the electric motor 208. In this case, the outer impeller 2021 is an electric impeller, and the central impeller is a mechanical impeller.

[0041] In some embodiments, the central impeller 2022 may not be directly driven by an electric device or motor 208. For example, but not limitingly, the drive may be performed via a planetary gear train driven by the output shaft of the accessory gearbox 104 and having elements adjusted by the adjusting device 208.

[0042] The circuit 102 also includes a control unit 206, which is configured to control an electric device or a motor 208.

[0043] The circuit 102 also includes a supply device 216 for supplying power to the circuit 102, which is driven by the output shaft 106 of the accessory gearbox 104 of the turbine engine 100. According to a variant not shown, the supply device 216 for supplying power to the circuit 102 may be driven by an electric device or a motor 208.

[0044] As previously described, supply device 216 is connected to Figure 4 Storage section R, not shown in the diagram.

[0045] The circuit 102 also includes a variable geometry supply loop 212 for the turbine engine 100, which connects the pump 200 and the variable geometry 212.

[0046] The circuit may also include a filter 214. The filter 214 may be connected to the supply device 212, the variable geometry supply loop 212 and the pump 200 to capture, for example, contaminants in the circuit, particularly contaminants from the variable geometry 212 or from the storage unit R, as well as contaminants on the path of the fuel toward the pump 200.

[0047] Fuel passing through the filter can also be directed toward other hydraulic circuits.

[0048] The circuit also includes a fluid mechanical unit 204 configured to control at least one fuel outlet toward the combustion chamber 108.

[0049] The fluid machinery unit 204 can be configured to receive the flow setpoint P from the computer (not shown) of the turbine engine 100. c To meet demand. For example, but not exclusively, takeoff.

[0050] The fluid machinery unit 204 can also be connected to the control unit 206 of the electric device or motor 208 to send signals to the flow setpoint P. c At least one relevant calibration setpoint. The calibration setpoint can be the pressure variation to be supplied. P reg And / or the action or series of actions to be applied to the centrifugal pump 200 to achieve a pressure change. P reg This is to regulate the fuel supply in circuit 102 and meet the needs of turbine engine 100. These actions may, for example but not limited to, increase or decrease the rotational speed of at least one impeller 2021, 2022 of centrifugal pump 200.

[0051] In another variation, the fluid electrical unit can be directly connected to the electrical equipment or motor 208. In this configuration, the control unit 206 of the speed regulation device can be integrated into the fluid mechanical unit 204.

[0052] Reference Figure 6 The fluid mechanical unit will now be described.

[0053] The fluid machinery unit 204 includes at least one metering device 302, which is configured to deliver fuel to the fuel outlet at a flow rate equal to or corresponding to the flow setpoint P. c Traffic.

[0054] The fluid machinery unit 204 also includes a servo valve 300 connected to the metering device 302. The servo valve is configured to receive a flow setpoint P. c The position of the metering device 302 is controlled.

[0055] When the turbine engine is ignited, pump 200 is driven at minimum rotational speed and supplies pressure P at the outlet (e.g., P=P0). When servo valve 300 receives setpoint P... c When activated, the servo valve controls the position of the metering device 302, ensuring that the pressure downstream of the metering device equals the pressure P. c This will cause a pressure change at the port of metering device 302. P1.

[0056] The fluid machinery unit 204 also includes a regulating valve 304, which is disposed downstream of the metering device 302 and configured to maintain a pressure difference or pressure change at the port of the metering device 302. P1 is constant. The regulating valve generates a variable constraint, thereby changing the constant pressure at the port of the metering device. P1 is configured to adapt to the characteristics of centrifugal pump 200. For example, if there is high pressure upstream of the control valve relative to a given pressure in the downstream loop (which depends on flow rate and flight conditions), a large pressure drop will occur. The passage cross-section (constraint) of the control valve will open. This will reduce the upstream pressure until the desired pressure difference or pressure change is achieved. Therefore, control valve 304 is controlled by metering device 302. P1 is hydraulically controlled at a constant value, but the pressure drop at the port of regulating valve 304 is variable. This pressure drop corresponds to pressure changes. P2.

[0057] The fluid machinery unit may also include a shut-off valve 310 located downstream of the regulating valve for injecting fuel into the combustion chamber 108 to shut off fuel injection and ensure that the circuit is sealed.

[0058] Still refer to Figure 6 The fluid machinery unit 204 also includes a measuring device 3062 disposed at the port of the regulating valve 304, relative to the flow setpoint P. c Detect or assess pressure drop P2.

[0059] Measuring device 3062 can be a pressure sensor or a valve core / locking element, the movement of which is caused by pressure drop. P1 controls the movement of the components and its position can change the speed of the impeller (e.g., via a continuously variable transmission). Preferably, the measuring device 3062 is a pressure sensor.

[0060] The fluid machinery unit 204 may also include a measuring device 3061 (e.g., a pressure sensor or valve core / locking mechanism), which is arranged at the port of the metering device to measure the flow rate setpoint P. c Detect or assess pressure difference.

[0061] The fluid machinery unit 204 is also configured to detect or evaluate pressure drop relative to the flow setpoint. P2 or relative to the flow setpoint P c Detecting or assessing pressure difference In the case of P1, the calibration setpoint is sent to the control unit 206 of the speed regulation device 208, so that the control unit 206 bases the calibration setpoint on the assessed pressure drop. P2 or based on the assessed pressure difference P1 controls the speed regulating device 208 to change the rotational speed of the pump's central impeller 2022, thereby adapting the pressure supplied by the centrifugal pump 200 to the needs of the hydraulic circuit downstream of the regulating valve or fluid machinery unit.

[0062] The fluid machinery unit may also include a selector (not shown) to select pressure drop or pressure difference according to predetermined criteria.

[0063] The center impeller 2022 is sized to supply approximately 25% of the total power required for the flow setpoint, and the outer impeller 2021 is sized to supply approximately 75% of the total power.

[0064] Furthermore, the dimensions of the central impeller 2022 and the outer impeller 2021 are designed such that the rotational speed of the central impeller 2022 driven by the speed regulating device 208 is preferably + / -30% of the rotational speed of the outer impeller 2021 driven by the output shaft 106 of the accessory gearbox 104 of the turbine engine 100.

[0065] As described, the counter-rotating centrifugal pump 200 enables pressure to be obtained with a smaller overall radial dimension than a conventional single-stage centrifugal pump, and an overall radial dimension on the same order of magnitude as a two-stage centrifugal pump.

[0066] During operation, the pressure supplied at the outlet by the counter-rotating pump 200 The change in P can be described by the following relationship: [Mathematical Expression 1]

[0067] Where s, e, and i are exponents representing parameters considered at the pump outlet, pump inlet, and the junction of the central and outer impellers; U is the tangential velocity of the impeller; Cu is the tangential velocity of the fuel; and g is the intensity of the gravitational field. The density of the fuel; For efficiency.

[0068] The combined effect of the junction between the two impellers increases the outlet pressure.

[0069] Now we will describe illustrative and non-restrictive examples of how the supply system works.

[0070] For a given requirement associated with a flight point (e.g., takeoff, in a non-restrictive manner), the flow setpoint P c The setpoint current is sent from the aforementioned computer of the turbine engine 100 to the servo valve 300. The servo valve 300 is then activated and controls the position of the metering device 302 to deliver the required flow rate. Based on the pressure P delivered by the centrifugal pump 200 and the flow rate demand, a pressure drop will be obtained at the port of the regulating valve 304. P2.

[0071] For example, for high rotational speeds and low flow rate requirements in the circuit downstream of fluid machinery unit 204 or control valve 304, the pump pressure will be high. Control valve 304 will then close to obtain the corrected pressure drop at the control valve port as measured by measuring device 3062. Pressure change at port P2 or metering device 302 P1. If the pressure drops... Pressure difference at the port of P2 or the metering device P1 is greater than the second given threshold, which means that the pressure P supplied by the pump upstream of the metering device 302 is too high, and the rotational speed of the pump 200 must be reduced to reduce the pressure P at the outlet of the pump 200.

[0072] Then, the calibration setpoint is sent from the fluid machinery unit 204 to the control unit 206 of the speed regulating device 208. Upon receiving the calibration setpoint, the control unit adjusts the rotational speed of the central impeller 2022, causing the pressure to drop. P2 or pressure difference P1 equals the pressure received at the calibration setpoint. P reg .

[0073] Similarly, under flow demand from variable geometry 212, the pressure P at the pump outlet will decrease. To adapt to the pump's characteristics, regulating valve 304 opens, reducing its pressure drop. P1. This will cause the rotational speed of device 208 to increase, thereby increasing the pressure P at the outlet of pump 200.

[0074] The invention described also enables coverage of the entire flight domain in the event of the loss of sensors 3061 and 3062. If sensors 3061 and 3062 cease to function, adjustment can result in the maximum speed of the impeller of pump 200, in which case the pump will deliver at a high power level. The power may no longer be suitable for a given operating point, but the supply system described above enables the turbine engine's needs to be met at all operating points within the domain.

[0075] Advantageously, those skilled in the art will understand that the mixed-fuel circuit architecture, as described, which uses the output shaft 106 of the turbine engine 100 and the speed regulation device 208 to drive the impellers 2021, 2022 of the counter-rotating centrifugal pump, enables the regulation of pressure levels to suit the needs of the turbine engine 100 and thus achieves a drive power gain.

[0076] This invention also enables the elimination of, for example Figure 1 The described recirculation loop B rec .

[0077] Furthermore, regulating by measuring the pressure drop at the port of regulating valve 304 means that the fuel supply system will always be operational even if the measuring device at the valve port fails. Therefore, regulation is improved.

[0078] Reference Figure 7It describes a variation of the fuel supply system.

[0079] The fuel supply system includes a circuit 102' similar to the circuit 102 described above, except that circuit 102' also includes a secondary fuel circuit 218. Therefore, circuit 102' includes a main circuit and a secondary circuit 218, the main circuit including a supply branch for combustion chamber 108.

[0080] The secondary fuel circuit 218 may include a hydromechanical unit 204' configured to control at least one fuel outlet for circuit 124, which supplies fuel to another area of ​​the turbine engine.

[0081] Adjustments to the fuel supply in the secondary circuit 218 do not result in adjustments to the primary circuit. The system is configured such that adjustments occur via a branch of the circuit (which includes the supply to the combustion chamber 108, i.e., the primary circuit). Therefore, if there is a demand for fuel in the secondary circuit 218, this will result in a fuel shortage in the primary circuit. Adjustments as described above can then be performed.

[0082] Advantageously, those skilled in the art will understand that, due to the architecture of the supply circuit as described above, multiple secondary circuits can be supplied via the centrifugal pump 200, which serves as a pressure source, while ensuring the regulation of fuel supply in the main circuit.

[0083] The present invention also relates to a method for regulating a fuel pump in a turbine engine of an aircraft, the turbine engine including a supply system according to the invention.

[0084] The method for regulating pump 200 executes a control rule 400 for the rotational speed of the impeller of pump 200, which increases or decreases the speed accordingly when the pressure difference or pressure drop decreases or increases, so that the flow rate and pressure at the outlet of loop 102 are adapted to the flight conditions of the aircraft.

[0085] The control rule 400 is configured to also adapt the flow rate supplied by pump 200 and the pressure in loop 102 to the operating conditions of secondary supply loop 218 or variable geometry 212.

[0086] Reference Figure 8 Control rule 400 must include at least: -Receives 500 flow rate setpoints; - Relative to the flow setpoint P c Assess the pressure difference of 502 P1 or relative to the flow setpoint P c Assessing stress reduction P2; -Based on the assessed pressure difference P1 or pressure drop based on assessment P2 changes the rotational speed of the central impeller 2022 of pump 504 200 according to the flow setpoint P. c The relevant requirements are adapted to the pressure supplied by pump 200.

[0087] As can be clearly seen from the above, the present invention (particularly controlling the speed of the speed regulating device by regulating the pressure drop at the port of the valve or by the pressure difference at the port of the metering device) enables the pump to be driven at both low and high speeds while achieving efficiency adapted to demand to reduce thermal rejection. In particular, a recirculation loop is no longer required.

[0088] The present invention also saves energy and material resources by adapting to pressure requirements while avoiding excessively large pump components to achieve maximum power or by adding a rotating gear system to control the speed of the pump impeller.

Claims

1. A system for supplying fuel to a turbine engine (100), the turbine engine (100) including at least one accessory gearbox (104) including at least one output shaft, the system including a fuel circuit (102) comprising: - The output shaft (106) of the accessory gearbox (104); - A counter-rotating centrifugal pump (200), the counter-rotating centrifugal pump comprising at least two concentric impellers (2021, 2022): At least one outer impeller (2021) is configured to be driven to rotate in a first direction by the output shaft of the accessory gearbox (104) of the turbine engine to deliver a certain flow rate of fuel to the circuit (102); At least one central impeller (2022) is configured to rotate in a second direction opposite to a first direction of the outer impeller; - A fluid mechanical unit (204) configured to control at least one fuel outlet toward the combustion chamber (108); The system is configured to operate based on a flow setpoint (P) in the hydraulic circuit downstream of the fluid machinery unit (204). c To regulate the flow rate of fuel toward the combustion chamber (108), Its features are: - The fluid machinery unit (204) includes at least one measuring device (3061, 3062), the at least one measuring device being configured to measure the flow rate setpoint (P). c Assess the pressure difference ( P1) or relative to the flow setpoint (P) c Assess the pressure drop ( P2); and The system further includes a speed regulating device (208) and at least one control unit (206), the speed regulating device being configured to control the rotational speed of the central impeller (2022), and the at least one control unit being used to control the speed regulating device (208) according to the assessed pressure drop ( P2) or based on the assessed pressure difference ( P1) Change the rotational speed of the central impeller (2022) of the pump so that the pressure supplied by the pump (200) via the drive of the outer impeller (2021) is adapted to the flow setpoint (P). c (Related needs) 2. The system according to claim 1, wherein, The pump (200) includes at least one mechanical impeller and one electric impeller.

3. The system according to claim 1 or 2, wherein, The electric impeller is a central impeller (2022), and the speed regulating device (208) is an electric system or a motor.

4. The system according to any one of claims 1 to 3, wherein, The dimensions of the central impeller (2022) are designed to supply the flow setpoint (P). c The outer impeller (2021) is sized to supply approximately 75% of the total power required, which is about 25% of the total power.

5. The system according to any one of claims 1 to 4, wherein, The dimensions of the central impeller (2022) and the outer impeller (2021) are designed such that the rotational speed of the central impeller (2022) driven by the speed regulating device (208) is + / -30% of the rotational speed of the outer impeller (2021) driven by the output shaft (106) of the accessory gearbox (104) of the turbine engine (100).

6. The system according to any one of claims 1 to 5, wherein, The fluid machinery unit (204) further includes at least: - Metering device (302), the metering device being configured to deliver a flow rate equal to the setpoint (P) toward the fuel outlet. c ) traffic; - Servo valve (300), the servo valve being configured to receive the flow setpoint (P) c And control the position of the metering device (302); - A regulating valve (304), which is disposed downstream of the metering device (302) and configured to maintain a pressure difference at the port of the metering device (302). P1) constant.

7. The system according to claim 6, wherein, The measuring devices (3061, 3062) include at least: - A first pressure sensor (3061), which is disposed at the port of the metering device (302) relative to the flow setpoint (P). c Assess the pressure difference ( P1); - A second pressure sensor (3062), configured to evaluate the pressure drop at the port of the regulating valve (304). P2), the pressure drop corresponds to the change in pressure.

8. The system according to any one of claims 1 to 7, wherein, The circuit (102) also includes: - A supply device (216) for supplying the circuit (102), the supply device being driven by the output shaft (106) of the accessory gearbox (104) of the turbine engine (100) or the speed regulating device (208); - Variable geometry supply loop (212) for the turbine engine (100); - Filter (214), which is connected at least to the supply device (216), the variable geometry supply loop (212) and the pump (200) to at least capture contaminants in the fuel.

9. A turbine engine (100) comprising the system according to any one of the preceding claims.

10. A method for regulating a centrifugal fuel pump (200) of a turbine engine (100) according to claim 9 in an aircraft, characterized in that, The method executes a control rule (400) for controlling the rotational speed of the impeller of the pump (200), the control rule increasing or decreasing the speed accordingly when the pressure difference or the pressure drop decreases or increases, so that the flow rate and pressure at the outlet of the circuit (102) are adapted to the flight conditions of the aircraft.

11. The method for regulating a pump according to the preceding claim, wherein, The control rule (400) is configured to also adapt the pressure supplied by the pump and the pressure in the circuit (102) to the operating conditions of the secondary supply circuit (218) or the variable geometry (212).

12. The method for regulating a pump according to claim 10 or 11, wherein, The control rule (400) includes at least: - Receive (500) flow setpoint (P) c ); - Relative to the flow setpoint (P) c ) Assessment (502) pressure difference ( P1) or relative to the flow setpoint (P) c Assess the pressure drop ( P2); -Based on the assessed pressure difference ( P1) or based on the assessed pressure drop ( P2) Change the rotational speed of the central impeller (2022) of the pump (200) according to the flow setpoint (P c The relevant requirements are adapted to the pressure supplied by the pump (200).

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