Management of mechanical energy storage from a two-shaft

Abstract

The invention relates to a method and a system for managing the acquisition of mechanical energy from a two-shaft or three-shaft turbine engine (1) of an aircraft, in which at least two motors (3, 4) are adapted to recover mechanical energy, one motor recovering mechanical energy from a shaft driven by one of a plurality of turbines of the turbine engine (1), and the other motor recovering mechanical energy from a shaft driven by a plurality of turbines of the turbine engine (1). One of the two motors (3, 4) recovers mechanical energy from a shaft driven by one turbine, the other recovers mechanical energy from a shaft driven by the other turbine, and the acquisition distribution between one and the other of the two motors (3, 4) is dynamically controlled according to the flight phase.

Description

Technical Field

[0001] The present invention relates to systems and methods for managing mechanical energy extraction from a dual-shaft or triple-shaft turbine engine. Background Art

[0002] Typically, in addition to generating thrust, aircraft turbine engines also serve as a source of mechanical energy for generating the electrical energy required by the aircraft. Typically, this mechanical energy from the turbine engine is taken from the high-pressure shaft, which imposes severe restrictions on the operability of the high-pressure compressor and the operability of the low-pressure compressor (or "thruster").

[0003] Furthermore, the system for managing the electrical energy harvesting considers the engine as a continuously available source. As long as the energy consumption demand is currently within a range that is considered acceptable, no attempt is made to control or optimize the energy level harvested.

[0004] However, such operation is increasingly incompatible with the significant reduction in idle thrust requirements of the latest generation aircraft, as a result of the increase in the aircraft's lift-to-drag ratio.

[0005] The descent phase is particularly affected. Specifically, this phase is characterized by the aircraft speed (in feet per minute) or the aircraft's descent gradient (in degrees), and is fundamentally limited by the aircraft's lift-to-drag ratio, which affects the descent rate by up to 90%. Therefore, an increase in the lift-to-drag ratio must be compensated by a significant reduction in idle thrust to maintain the target descent rate.

[0006] However, the reduction of idle thrust is in conflict with the need to capture electrical energy: since the dimensions of the engine components, the HP compressor and the LP compressor ("thruster"), must take into account the failure of the generator, the surge margin and the acceleration capability of the HP compressor are limited by the relative energy capture of the HP turbine.

[0007] Recently, in the context of hybrid drive propulsion units, new architectures that implement multiple mechanical acquisitions have also been proposed. The first mechanical acquisition remains unchanged: energy is extracted from the HP shaft. In addition, a second mechanical acquisition is performed from the LP shaft. Summary of the invention

[0008] The general purpose of the invention is to improve the management of mechanical and electrical energy extraction in order to make the development of idle thrust reduction and the need for electrical energy extraction as compatible as possible.

[0009] According to one aspect, for this purpose, the invention provides a system for managing the extraction of mechanical energy from a two-shaft or three-shaft aircraft turbine engine comprising at least a first turbine and a second turbine,

[0010] wherein at least the first and second electric machines are adapted to recover mechanical energy,

[0011] the first electric machine recovers mechanical energy from a shaft driven by a first turbine of the turbine engine,

[0012] the second electric machine recovers mechanical energy from a shaft driven by a second turbine of the turbine engine,

[0013] The system comprises:

[0014] a management unit that controls the acquisition of electrical energy and the way in which it is distributed between the various equipment and consumer systems of the aircraft, and

[0015] a control unit adapted to send an acquisition allocation to the management unit, the acquisition allocation being determined by the control unit as a function of the flight phase of the aircraft,

[0016] Therefore, the inventors have realized that the way of distribution of the harvest has an impact on the operation of the turbine engine. Specifically, the mechanical harvest affects the overall serviceability of the turbine engine and the operating point of the components. Therefore, for the same overall mechanical energy demand, the distribution method will affect the consumption of fuel or the engine thrust.

[0017] Typically, for example, in the case of a two-shaft turbine engine, having two generators suitable for recovering mechanical energy (one generator recovering mechanical energy from the HP shaft and the other generator recovering mechanical energy from the LP shaft), the impact caused by the generator on the LP shaft is different from that of the generator on the HP shaft, in particular with regard to the margin, thrust and specific fuel consumption (SFC) of the compressor.

[0018] The provided system has the advantage of enabling the following optimizations:

[0019] - Optimization of specific fuel consumption (SFC);

[0020] -Thrust optimization;

[0021] -Optimization of acceleration time;

[0022] -Optimization of turbine outlet temperature.

[0023] In particular, therefore, the presence of the generator on the LP shaft increases the degree of freedom making it possible to find the best compromise according to the desired criteria.

[0024] The invention also provides a method for managing the extraction of mechanical energy from a two-axis or three-axis aircraft turbine engine, the two-axis or three-axis aircraft turbine engine comprising at least a first turbine and a second turbine,

[0025] wherein at least the first and second electric machines are adapted to recover mechanical energy,

[0026] a first electric machine recovers mechanical energy from a shaft driven by a first turbine of the turbine engine, and

[0027] a second electric machine recovers mechanical energy from a shaft driven by a second turbine of the turbine engine,

[0028] The method performs control of the acquisition of electrical energy and the manner in which it is distributed between the various equipment and consumer systems of the aircraft,

[0029] The acquisition allocation mode between the first motor and the second motor is dynamically controlled according to the flight phase.

[0030] The invention also relates to an assembly comprising a two-axis or three-axis aircraft turbine engine, the two-axis or three-axis aircraft turbine engine comprising at least a first turbine and a second turbine,

[0031] wherein at least the first and second electric machines are adapted to recover mechanical energy,

[0032] a first electric machine recovers mechanical energy from a shaft driven by a first turbine of the turbine engine, and

[0033] a second electric machine recovers mechanical energy from a shaft driven by a second turbine of the turbine engine,

[0034] The components also include a management system as described above.

[0035] At least one of the electrical machines may be a generator.

[0036] In the case where the turbine engine is of the two-shaft type, the electric machines are suitable for recovering mechanical energy, one from the high-pressure shaft and the other from the low-pressure shaft.

[0037] In the case of a turbine engine with a three-shaft architecture, the third electric machine draws mechanical energy from the intermediate pressure (IP) shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other characteristics, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and non-limiting and must be read with reference to the accompanying drawings, in which:

[0039] Figure 1 Schematically illustrates an example of a management system according to an embodiment and possible implementation of the present invention;

[0040] Figure 2 The schematic diagram in more detail shows Figure 1 A possible implementation of the system. DETAILED DESCRIPTION

[0041] Figure 1 The components shown include a twin-shaft turboshaft engine 1, a control unit 2, a generator 3 that recovers mechanical energy from the high-pressure HP shaft using an energy transfer system (not shown), and a generator 4 that itself recovers mechanical energy from the low-pressure LP shaft using another energy transfer system (also not shown).

[0042] The management unit 5 controls the extraction of electrical energy from the outputs of the generators 3 and 4 and the way in which it is distributed between the various equipment and consumer systems of the aircraft.

[0043] The control unit 2 and the management unit 5 constitute a management system of the components proposed in this application.

[0044] The distribution of the energy drawn from the generators 3 and 4 (which is carried out by the management unit 5 ) is determined by the engine control unit 2 and sent to said management unit 5 .

[0045] Typically, the input data considered for this purpose in Unit 2 is as follows:

[0046] - Flight data of the aircraft ( Figure 1 The "AD (Flight Data)" box in the figure), the flight data of the aircraft participates in the reconstruction of the flight phase;

[0047] - the position of the throttle valve M, which in particular provides information about the thrust demand,

[0048] - data W provided by aircraft sensors, such as "weight on wheels" data or gear extension and gear fold,

[0049] - TM data provided by the sensors of the turbine engine, which in particular define the transient / steady-state state of the turbine engine and also provide information on limitations related to the operability of the compressor.

[0050] The unit 2 uses these different data to determine the flight phase and the mechanical energy level required by the engine for the flight. The unit 2 derives from this the energy extraction distribution to be applied between the two generators 3 and 4. In the stable class of the turbine engine, for each flight phase and each desired mechanical energy level there is a corresponding optimized energy distribution, which is predetermined and stored in a memory in the unit 2.

[0051] Unit 2 can identify the flight phase as follows:

[0052] -Takeoff: The throttle valve M is in the takeoff position, and the altitude and speed are within the takeoff envelope;

[0053] - Climb: Throttle valve M is at or above the minimum "Climb" position; altitude and speed are outside takeoff phase conditions;

[0054] - Cruise: the level (or throttle M position) is between the cruise minimum and the climb threshold, and the altitude is greater than the cruise threshold altitude;

[0055] - descent: level (or throttle M position) below the threshold, landing gear retracted and altitude greater than the cruise threshold altitude;

[0056] - Approach: level (or throttle M position) below threshold, landing gear extended and not folded;

[0057] - Ground idle speed: the level (or throttle M position) is less than the threshold, the gear train extends and folds.

[0058] Therefore, the harvesting allocation will be dynamically managed during the flight phase according to the engine-specific requirements while meeting the overall energy needs of the aircraft.

[0059] The following table gives examples of how this might be allocated for different phases of flight.

[0060]

[0061] in:

[0062] NPE represents the level of non-propulsive energy and mechanical energy extracted from the engine.

[0063] 100% NPE represents a reference level relative to which the distribution between energy extraction from the HP axis and energy extraction from the BP axis is performed.

[0064] This distribution is determined by the unit 2 according to rules stored in the memory of the unit. The example given below enables the acquisition to be optimized with the goal of minimizing the SFC consumption of the engine. This example is particularly applicable to the case of bypass engine configurations with ultra-high bypass ratio (Ultra High Bypass Ratio, UHBR).

[0065] Take-off phase (TKOF):

[0066] o 100% of the electrical energy is obtained from generator 3 (HP shaft);

[0067] Climb

[0068] o Until 21,000 feet (6,400 m), 100% of the power is taken from Generator 3 (HP shaft) (“Climb 1500 ft (457 m) / M0.388” and “Climb 10 kft (3048 m) / M0.488” in the table above)

[0069] stage);

[0070] o Until 29,700 feet (9,052 m), 40% of the power is taken from generator 3 (HP shaft) and 60% from generator 4 (LP shaft) (the "climb 21,111 ft (6,434 m)" in the table above)

[0071] / M0.602” stage);

[0072] o From 29,700 feet (9,052 m) until 35,000 feet (10,668 m), 60% of the power is obtained from generator 3 (HP shaft) and 40% is obtained from generator 4 (LP shaft) (the "climb 29,753 ft (9,068 m) / M0.714" stage in the above table);

[0073] o Above 35,000 feet (10,668 m), 80% of the power is obtained from generator 3 (HP shaft) and 20% is obtained from generator 4 (LP shaft) (the "climb 35 kft (10,668 m)" in the above table)

[0074] / M0.77” stage).

[0075] Cruise (from 21,000 feet (6,400 m)):

[0076] o 40% of the electrical energy is obtained from generator 3 (HP shaft) and 60% from generator 4 (LP shaft)

[0077] (The “Cruise” phase in the table above).

[0078] By way of example, the quantities involved in terms of SFC consumption for such a UHBR engine are as follows:

[0079]

[0080] More generally, the control unit 2 has a distribution rule that is determined for a given engine or a given type of turbine engine, according to the desired optimization, according to the level of mechanical energy required by the engine for flight and according to the flight phase.

[0081] Optimization of SFC consumption is a possible optimization target for two-shaft or three-shaft turbine engines.

[0082] Therefore, the optimized table is as follows:

[0083]

[0084] The optimization may also depend on the overall level of energy harvested. Thus, the HP / LP split optimum level may vary depending on this harvest level.

[0085] Of course, other optimization goals are possible.

[0086] In particular, the optimization logic can be very different from one stage to another.

[0087] In particular, the acquisition distribution is carefully selected to minimize thrust at the idle (ground and descent) points.

[0088] In the case of an optimization of the thrust during the descent phase, the acquisition distribution is established according to the architecture of the aircraft, in particular according to the idle thrust specification of the aircraft, which is related in particular to the lift-to-drag ratio of the wing.

[0089] For example, the optimization table for descent thrust can be as follows:

[0090]

[0091]

[0092] Where a negative distribution corresponds to an injection of energy, the value is chosen so that the energy transfer between the axes is balanced and the motor does not take any energy from other sources of the aircraft.

[0093] At the same time, minimizing the “idle ground” thrust makes it possible to limit brake wear and temperatures during the taxiing phase of the aircraft.

[0094] Another possibility is to optimize the acquisition distribution to limit the turbine outlet temperature (TGT). In particular, operation in the ground idle phase under hot ambient temperature conditions is usually limited by the turbine outlet temperature, which makes it necessary to increase the idle level again to obtain an acceptable turbine outlet temperature for the material of the rear body of the turbine engine. A careful choice of the dynamic distribution of the acquisition makes it possible to limit the turbine outlet temperature.

[0095] For this goal, the optimal distribution is as follows: 60% HP / 40% LP

[0096] Another possible optimization, especially for the approach phase, is to minimize the acceleration time.

[0097] For this goal, the optimized distribution is as follows: 0% HP / 100% LP

[0098] like Figure 2 As shown, the control unit 2 incorporates subunits 6a to 6e for optimization according to different possible logics, a selection logic 7, a subunit 8 for determining the flight phase, and a subunit 9 for determining the steady state of the turbine engine.

[0099] The subunits 6 a to 6 e are supplied with flight data (altitude, speed, etc.) and also with data TM from sensors of the turbine engine 1 (for example the turbine outlet temperature).

[0100] The subunit 8 for determining the flight phase receives data such as the position of the throttle valve M, which in particular provides information on the thrust demand, or other data W provided by the sensors of the aircraft (for example “gear extended” and “gear folded”).

[0101] The subunit 9 simultaneously receives engine data TM provided by sensors of the turbine engine, in particular for defining transient / steady-state conditions of the turbine engine and also for providing information on limits relating to the operability of the compressor.

[0102] The output of the unit 8 for determining the flight phase is sent to the selection logic 7, which queries one of the subunits 6a to 6e according to the identified flight phase, so that the selected subunit uses the stored optimization table to provide an optimized acquisition distribution method according to these data and according to the optimization objectives corresponding thereto and corresponding to the flight phase.

[0103] An example of optimal selection according to the phase can be as follows (stable engine):

[0104] - Take-off: Optimization of specific fuel consumption (SFC) (subunit 6a);

[0105] - Climb: Optimization of specific fuel consumption (SFC) (subunit 6a);

[0106] - Cruising: Optimization of specific fuel consumption (SFC) (subunit 6a);

[0107] - descent: optimization of thrust (subunit 6b);

[0108] - Landing approach: Optimization of acceleration time (subunit 6c);

[0109] - Ground idle: Optimization of turbine outlet temperature TGT (subunit 6d).

[0110] Other optimization options are of course possible (subunit 6e). In particular, for the idle phase, it is also possible to optimize for the residual thrust, or for a compromise between optimization for the residual thrust and optimization for the turbine outlet temperature TGT.

Claims

1. A system for managing the extraction of mechanical energy from a two-axis or three-axis aircraft turbine engine (1), the two-axis or three-axis aircraft turbine engine comprising at least a first turbine and a second turbine, in, At least the first electric machine (3) and the second electric machine (4) are adapted to recover mechanical energy: As for the first electric machine (3), the first electric machine recovers mechanical energy from a shaft driven by a first turbine of the turbine engine, As for the second electric machine (4), the second electric machine recovers mechanical energy from a shaft driven by a second turbine of the turbine engine, Wherein, the system comprises: - a management unit (5) which controls the acquisition of electrical energy and the manner in which it is distributed between the various equipment and consumer systems of the aircraft, and a control unit adapted to send an acquisition allocation to the management unit (5), the control unit determining the acquisition allocation according to the flight phase of the aircraft, - the control unit (2) is suitable for storing acquisition allocation rules for different optimization logics, the stored acquisition allocation rules corresponding to an optimization logic selected from the following group: optimization of specific fuel consumption (SFC) and / or optimization of thrust and / or optimization of acceleration time and / or optimization of turbine outlet temperature.

2. A method for managing the extraction of mechanical energy from a two-axis or three-axis aircraft turbine engine (1), the two-axis or three-axis aircraft turbine engine comprising at least a first turbine and a second turbine, in, At least the first electric machine (3) and the second electric machine (4) are adapted to recover mechanical energy: - for the first electrical machine (3), said first electrical machine recovers mechanical energy from a shaft driven by a first turbine of said turbine engine (1), and - for the second electric machine (4), the second electric machine recovers mechanical energy from a shaft driven by a second turbine of the turbine engine, The method performs control of the acquisition of electrical energy and the manner in which it is distributed between the various equipment and consumer systems of the aircraft, The acquisition distribution mode between the first motor (3) and the second motor (4) is dynamically controlled according to the flight phase, wherein the control unit (2) stores acquisition distribution rules for different optimization logics, and the stored acquisition distribution rules correspond to the optimization logic selected from the following group: optimization of specific fuel consumption (SFC) and / or optimization of thrust and / or optimization of acceleration time and / or optimization of turbine outlet temperature.

3. The method according to claim 2, wherein: In particular, the control unit (2) determines the flight phase of the aircraft based on the information items (AD) sent by the aircraft and sends the distribution method to be applied to the management system (5) controlling the acquisition of electrical energy, the distribution method being based on an optimization logic specific to the determined flight phase.

4. The method according to claim 3, wherein: The control unit determines the flight phase and the allocation method according to input data, wherein the input data includes - flight data (AD) of the aircraft; - thrust demand and / or throttle (M) position; - data (W) provided by the aircraft sensors, such as landing gear deployment and landing gear folding, - data (TM) provided by sensors of the turbine engine (1), in particular data provided by sensors of the turbine engine for defining transient / steady-state conditions of the turbine engine.

5. The method according to claim 4, wherein: The optimization logic for different flight phases includes: -Takeoff: Optimization of specific fuel consumption (SFC); - Climb: Optimization of specific fuel consumption (SFC); - Cruise: Optimization of specific fuel consumption (SFC).

6. The method according to the preceding claim, wherein: The optimization logic for different flight phases also includes: -Descent: optimization of thrust; - Landing approach: Optimization of acceleration time; - Ground idle: Optimization of turbine outlet temperature TGT.

7. The method according to claim 5 or 6, wherein: The stored acquisition allocation rules take into account the altitude of the aircraft.

8. An assembly comprising a two-axis or three-axis aircraft turbine engine (1), the two-axis or three-axis aircraft turbine engine comprising at least a first turbine and a second turbine, in, At least the first electric machine (3) and the second electric machine (4) are adapted to recover mechanical energy: - the first electric machine (3) recovers mechanical energy from a shaft driven by a first turbine of the turbine engine (1), and - the second electric machine (4) recovers mechanical energy from a shaft driven by a second turbine of the turbine engine, Wherein, the component further comprises a management system according to claim 1.

9. The assembly according to claim 8, wherein: The turbine engine is of a dual-shaft type, and the electric motors are two generators suitable for recovering mechanical energy, one generator recovering mechanical energy from the high-pressure shaft of the turbine engine, and the other generator recovering mechanical energy from the low-pressure shaft.

10. An aircraft comprising a system according to claim 1 or an assembly according to claim 8 or 9.

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