Positioning of a turbomachine air intake port

Abstract

The present invention relates to a turbomachine assembly (1), comprising: - a high-pressure compressor (5) configured to be driven by a high-pressure shaft (12); - a low-pressure compressor (4) configured to be driven by a low-pressure shaft (11), the low-pressure shaft (11) being configured to be driven at a lower speed than the high-pressure shaft (12); - a first power converter (21) configured to be driven by the high-pressure shaft (12); - an air-circulation system comprising a first air bleed port (9) positioned in the high-pressure compressor (5) and a second air bleed port (3) positioned upstream of the first air bleed port (9); - means (50) for determining an operating condition of the turbomachine assembly (1); and - a controller (40) configured to send, to the first power converter (21), instructions to transfer power from the high-pressure shaft (12) to the low-pressure shaft (11) or power from the low-pressure shaft (11) to the high-pressure shaft (12), according to the operating condition.

Description

[0001] Positioning of an air intake port of a turbomachine

[0002] FIELD OF THE INVENTION

[0003] This application generally concerns the field of turbomachines, and more particularly the sizing of the air intake on a high pressure compressor.

[0004] STATE OF THE ART

[0005] A turbomachine has a main direction extending along a longitudinal axis, and typically comprises, from upstream to downstream in the direction of gas flow, a fan and a primary body comprising a compression section which may comprise a low-pressure compressor, a high-pressure compressor, a combustion chamber, and a turbine section which may comprise a high-pressure turbine and a low-pressure turbine. The turbomachine may comprise two intake ports, a high-pressure intake port placed in the vicinity of the outlet of the high-pressure compressor and an intermediate intake port placed upstream. The two compressors can bilaterally transfer part of their mechanical power via electromechanical converters directly mounted on each shaft integral with the high-pressure and low-pressure compressors. This is referred to as a hybrid architecture.Reference can be made to document WO 2020 / 245516 for information on this type of architecture.

[0006] Reducing aircraft fuel consumption involves improving performance in terms of air intake needed to pressurize the cabin during all phases of flight.

[0007] These performances are intrinsically linked to the position of the bleed ports in the turbomachine. The turbomachine can thus include two ports at the compressor level. When the pressure at the most upstream port is too low, the air is bled at the port located at the compressor outlet. However, if the bled pressure is too high during a given flight phase, the efficiency of the corresponding compressor is intrinsically reduced. In addition, using air with too high a pressure requires oversizing the air cooling system, which implies additional costs in terms of consumption and equipment.

[0008] STATEMENT OF THE INVENTION An aim of the invention is therefore to remedy the problems of overpressure of the air taken from the low pressure compressor for the operation of the aircraft during the different phases of flight while maintaining the air pressure above a critical tipping point on a high pressure intake port.

[0009] For this purpose, a set of a turbomachine is proposed comprising:

[0010] - a high pressure compressor configured to be driven by a high pressure shaft;

[0011] - a low pressure compressor configured to be driven by a low pressure shaft, the low pressure shaft being configured to be driven at a lower speed than the high pressure shaft;

[0012] - a first power converter configured to be driven by the high pressure shaft;

[0013] - an air circulation system comprising a first air sampling port positioned in the high pressure compressor and a second air sampling port positioned upstream of the first air sampling port;

[0014] - means for determining an operating condition of the turbomachine assembly; and

[0015] - a controller configured to send instructions to transfer to the first power converter a power from the high pressure shaft to the low pressure shaft or a power from the low pressure shaft to the high pressure shaft depending on the operating condition.

[0016] It may be provided that the means for determining the operating condition comprise at least one of the following elements:

[0017] - a pressure sensor positioned at the second air sampling port;

[0018] - a calculator configured to estimate a pressure at the second air sampling port.

[0019] The first power converter can be provided to be an electromechanical converter operating in generator mode, the first power converter being able to take power from the high pressure shaft or transfer power to the high pressure shaft.

[0020] It may be provided that the assembly further comprises a second power converter receiving power from the first power converter, the second power converter being able to take power from the low pressure shaft or transfer power to the low pressure shaft.

[0021] The second power converter can be expected to be an electromechanical converter operating in motor mode.

[0022] The second air sampling port can be positioned in the high pressure compressor.

[0023] The high pressure compressor may be provided to comprise a given number of compression stages, the second port being positioned between the second stage and the fourth stage, preferably between the second stage and the third stage.

[0024] The invention also provides a turbomachine comprising the assembly as described above.

[0025] The invention also provides a method for controlling the turbomachine assembly as described above, comprising the following steps:

[0026] - determine an operating condition of the turbomachine assembly; and

[0027] - transferring power from the high pressure shaft to the low pressure shaft or power from the low pressure shaft to the high pressure shaft depending on the operating condition so as to increase a pressure at the second sampling port.

[0028] The invention also provides a method for dimensioning the turbomachine assembly as described above, comprising the following steps:

[0029] - determine a target pressure in the cruising phase of the turbomachine; and

[0030] - position the second sampling port so that the pressure at the second sampling port is equal to the target pressure.

[0031] DESCRIPTION OF FIGURES

[0032] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: Figure 1 schematically illustrates a half-section of an example of an aircraft turbomachine according to an embodiment of the invention;

[0033] Figure 2a is a simplified view of an example of a conventional turbomachine;

[0034] Figure 2b is a simplified view of another example of an aircraft turbomachine according to an embodiment of the invention;

[0035] Figure 3a is a graph showing the evolution of the pressure in the compressor of Figure 2b (in broken lines) and the compressor of Figure 2a (in solid lines) as a function of the position of the upstream air sampling port at takeoff and during climb;

[0036] Figure 3b is a graph representing the evolution of the pressure in the compressor of Figure 2b (in broken lines) and the compressor of Figure 2a (in solid lines) as a function of the position of the upstream air sampling port during cruising;

[0037] Figure 4 partially illustrates an information and power chain in which the steps of an implementation mode of the control method of the invention are detailed; and

[0038] Figure 5 is a flowchart illustrating an embodiment of the dimensioning method of the invention.

[0039] Throughout the figures, similar elements have identical references.

[0040] DETAILED DESCRIPTION OF THE INVENTION

[0041] A turbomachine 1 has a main direction extending along a longitudinal axis X, and typically comprises, from upstream to downstream in the direction of gas flow, a fan 2, a primary body comprising a compression section which may comprise a low-pressure compressor 4 and a high-pressure compressor 5, a combustion chamber 6, and a turbine section which may comprise a high-pressure turbine 7 and a low-pressure turbine 8. In one embodiment, the fan 2 may be ducted and housed in a retention casing and comprises a nacelle 10 defining an aerodynamic envelope of the engine 1. Alternatively, the fan may be unducted. The airflow entering the turbomachine 1 is divided into a primary flow configured to pass through the primary body and a secondary flow which bypasses the primary body and is compressed by the fan 2.

[0042] In addition, the turbomachine 1 can be shrouded and comprise more than two bodies.

[0043] The turbomachine 1 comprises at least two drive shafts, typically a high pressure shaft 12 and a low pressure shaft 11. The high pressure shaft 12 is connected to the high pressure turbine 7 and is configured to drive the high pressure compressor 5.

[0044] The low pressure shaft 11 is connected to the low pressure turbine 8 and is configured to drive the low pressure compressor 4.

[0045] In the case of a twin-spool turbomachine, the fan 2 is driven by the low-pressure shaft 11, either directly (as illustrated for example in figures 2a and 2b) by the low-pressure turbine, or via a reduction mechanism which may include an epicyclic reducer of the planetary or star type (see figure 1).

[0046] In the case of a triple-spool turbomachine, the fan 2 is driven by a third shaft connected to an intermediate turbine extending between the high-pressure turbine 7 and the low-pressure turbine 8. The low-pressure turbine 8 then only drives the low-pressure compressor 4, directly or via a reduction mechanism.

[0047] In the present application, upstream and downstream are defined relative to the normal flow direction of the gas in the turbomachine 1. Thus, the X axis of the turbomachine 1 corresponds to the axis of rotation of its rotor parts.

[0048] Turbomachine 1 also includes:

[0049] - a first power converter 21, or HP converter 21, configured to be driven by the high pressure shaft 12;

[0050] - an air circulation system comprising two upstream 3 and downstream 9 sampling ports; and

[0051] - means for determining an operating condition 50 of the turbomachine 1 and a controller 40 configured to send instructions to transfer to the first power converter 21 a power from the high pressure shaft 12 to the low pressure shaft 11 or a power from the low pressure shaft 11 to the high pressure shaft 12 depending on the operating condition.

[0052] The downstream port 9 is positioned in the high pressure compressor 5. The upstream port 3 is placed upstream of the downstream port 9. In one embodiment, the upstream port 3 is also positioned in the high pressure compressor 5.

[0053] The pressure of the air taken from each port 3, 9 depends on the position of the port in the high pressure compressor 5. The further upstream the port is, the lower the pressure taken.

[0054] The air taken by each port 3, 9 passes through an expansion member making it possible to adapt the pressure and the temperature for different applications such as air conditioning for an aircraft cabin or de-icing the wings of an aircraft. The turbomachine 1 comprises a first electromechanical converter 21 mechanically connected to the high pressure shaft 12 via an accessory box 20 and a second electromechanical converter 31 mechanically connected to the low pressure shaft 11 via a coupling device 30 and electrically to the first converter 21 via an internal electrical network 14.Depending on the operating condition of the turbomachine 1, the first converter 21 is configured to take power from the high pressure shaft 12 and transfer this power to a part of the turbomachine 1, for example to the low pressure shaft 11 and the second electromechanical converter 31 configured to be driven by the low pressure shaft 11 and receive the power from the first converter 21. The first converter 21 then operates in generator mode and the second converter 31 then operates in motor mode. Alternatively, the second converter 31 may be configured to take power from the low pressure shaft 11 and transfer this power to a part of the turbomachine 1, for example to the high pressure shaft 12 and the first electromechanical converter 21 may be configured to be driven by the high pressure shaft 12 and receive the power from the second converter 31.The second converter 31 then operates in generator mode and the first converter 21 then operates in motor mode. It will be noted that the operation (motor / generator) of the first and second converters 21, 31 depends on the operating condition of the turbomachine 1 (which is defined later in the description).

[0055] The first and second converters 21 and 31 are therefore preferably reversible type rotating electrical machines capable of operating in a motor mode and in a generator mode. In the motor mode, a rotating electrical machine transforms electrical energy taken from the internal electrical network 14 into mechanical energy injected onto the low pressure shaft 11 or the high pressure shaft 12. For this purpose, the electrical power module 22, 32 operates in an inverter mode to transform a direct voltage from the internal electrical network 14 into a polyphase alternating voltage applied to the phases of the corresponding rotating electrical machine.

[0056] In the generator mode, a rotating electrical machine transforms mechanical energy taken from the low pressure shaft 11 or the high pressure shaft 12 into electrical energy injected into the internal electrical network 14 of the turbomachine 1. For this purpose, the electrical power module 22, 32 operates in a rectifier mode to transform a polyphase alternating voltage generated by the rotating electrical machine into a direct voltage applied to the internal electrical network 14.

[0057] The first and second converters 21 and 31 are preferably permanent magnet synchronous type machines. Alternatively, the first and second converters 21 and 31 may comprise asynchronous type electrical machines or any other type of electrical machine suitable for the application.

[0058] In the following, the invention will be mainly described in the operating case where the first converter 21, or HP converter 21, operates in generator mode and the second converter, or LP converter 31, operates in motor mode to simplify the description. As indicated above, the first converter 21 can however operate in motor mode and the second converter 31 can operate in generator mode, depending on the operating condition of the turbomachine 1.

[0059] Where appropriate, the coupling device 30 may integrate a mechanical function for uncoupling the BP converter 31, particularly in the event of a malfunction of the latter.

[0060] The internal electrical network 14 of the turbomachine 1 is preferably a continuous electrical network.

[0061] Electrical power modules 22, 32 can be electrically connected to the BP 31 and HP 21 converters. In this case, the electrical power modules 22, 32 are electrically connected to the internal electrical network 14 of the turbomachine 1.

[0062] In the embodiment illustrated in the figures, the power flow is directed from the high pressure shaft 12 to the low pressure shaft 11. Thus, a mechanical rotational power of the high pressure shaft 12 is converted by the HP converter 21 into alternating electrical power and then modulated by the electrical power module 22 as a rectifier in order to be transported in the form of continuous electrical power to the inverter 32 making it possible to obtain at the output an alternating electrical power converted by the LP converter 31 into a mechanical rotational power transmitted to the low pressure shaft 11.

[0063] The means for determining the operating condition 50 of the turbomachine 1 may comprise at least one of the following means, configured to measure and / or estimate given parameters:

[0064] - a pressure sensor positioned at the upstream port 3;

[0065] - a computer configured to estimate a pressure at the second air sampling port 3, the computer being able to implement for example an algorithm or a map modeling the turbomachine 1 obtained by ground tests or by calculations.

[0066] All or part of the measured and / or estimated parameters thus make it possible to define the operating condition of the aircraft. The controller 40 is configured to receive the measured and / or estimated parameters as input and send instructions to transfer power from the high pressure shaft 12 to the low pressure shaft 11 to the HP converter 21 as a function of these parameters. The power level to be taken from the high pressure shaft 12 is estimated by the controller 40 from the target pressure value to be reached at the upstream port 3. The controller then transmits, as output, a torque setpoint to control the electromechanical converter 21 via the electrical power module 22. The power module can be in a PWM or full wave mode.

[0067] E0 control method according to an embodiment of the invention

[0068] The hybrid architecture with an HP converter 21 and a LP converter 31 allows power transfers that can be used to increase, depending on the flight phases, the pressure of the air taken from the upstream port 3. Thus, the upstream port 3 is virtually “moved” according to the power transferred to the low pressure shaft 11. It is therefore possible to adapt the pressure at the upstream port 3 as closely as possible according to the pressure requirements of the aircraft and / or to place the upstream port 3 in a stage of the high pressure compressor 5 further upstream than in conventional turbomachines.

[0069] Thus, when the high pressure compressor 5 comprises between 6 and 12 stages, the upstream port 3 can be positioned between the second stage and the fourth stage of the high pressure compressor 5, preferably at the second stage or the third stage of the high pressure compressor 5. Indeed, when the pressure at the upstream port 3 is too low to ensure sufficient pressurization of the cabin, increasing the rotation speed of the low pressure shaft 11 by means of the controller 40 and the HP converter 21 makes it possible to increase the pressure at the upstream port 3.

[0070] It should be noted that each operating condition implies different pressure conditions at the compression assembly. Thus, for the same stage of a compressor 4, 5, the pressure can change at this stage between two flight phases. Therefore, the pressure at the sampling ports 3, 9 is modified, which implies an increase in the consumption of the air regulation equipment.

[0071] For example, in the configuration of the turbomachine 1 illustrated in Figure 2a, the upstream port 3 is placed so that the intake pressure is at a value close to a target pressure corresponding to the aircraft's requirement during the most demanding flight phase, for example the waiting or end-of-cruise phase. In Figure 3a, this point corresponds to a pressure value P1 located at the limit of the pressure requirements represented by a horizontal line at the pressure value P3.

[0072] During the cruise flight phase, the operating conditions of the turbomachine change, in particular the pressure at the compression section. The pressure required by the aircraft, represented by the horizontal line at the pressure value P4, is then lower than the effective pressure P2 at the upstream port 3, which is fixed in the high-pressure compressor 5. There is then a pressure difference AP between the pressure point P2 and the pressure requirement P4, since the pressure taken is too high compared to the required pressure P4. This pressure difference AP, however, reduces the efficiency of the high-pressure compressor 5 and causes excess fuel consumption.

[0073] The use of the HP converter 21 makes it possible to move the upstream port 3 upstream, so that the pressure point P2 corresponds to the target value P4 in the cruise phase (which generally corresponds to the longest flight phase during a mission), while compensating for the missing pressure during the most demanding flight phase by ensuring a pressure equal to the target value P3 thanks to the power draw from the high pressure shaft 12. The pressure P2 at the upstream port 3 is therefore equal to the pressure P4 required in the cruise phase, so it is normally not necessary to draw power from the high pressure shaft 12. On the other hand, during the most demanding flight phase, the power flow 13 transferred from the high pressure shaft 12 to the low pressure shaft 11 makes it possible to maintain the operating point at pressure P3.Indeed, the evolution of the pressure in the case of the architecture of figure 2b is identical in figure 3a and in figure 3b.

[0074] The method for controlling the HP converter 21 and the LP converter 31 of the turbomachine 1, illustrated in Figure 4, has the following steps.

[0075] During a step E1, an operating condition of the turbomachine is determined from the data from the sensors 50.

[0076] During a step E2, the controller 40 compares the operating condition thus determined (for example, the pressure at the upstream port 3) with a predefined operating condition (for example the pressure P3 or P4) and, if necessary, controls the HP converter 21 and, optionally, the LP converter 31, so as to transfer power from the high pressure shaft 12 to the low pressure shaft 11 or power from the low pressure shaft 11 to the high pressure shaft 12 depending on the operating condition thus determined. The pressure at the upstream port 3 is then modified.

[0077] Steps E1 and E2 are repeated until the determined operating condition matches the predefined operating condition. The method has the advantage of theoretically saving up to 1% of the fuel carried by the aircraft. By advancing the upstream port 3 by one stage (for example, a change from the fourth to the third stage of a ten-stage high-pressure compressor 5), the fuel saving can reach 0.5%.

[0078] E10 dimensioning method according to one embodiment of the invention

[0079] There is a position of upstream port 3 for which, in cruise phase, the pressure at upstream port 3 corresponds to the pressure corresponding to the aircraft requirement P4. This point implies undersizing upstream port 3 during other flight phases and using the power transfer between high pressure shaft 12 and low pressure shaft 11 to maintain the intake pressure at the target pressure value P3.

[0080] The process of sizing a turbomachine assembly 1 to find this position is illustrated by the flowchart in Figure 5, each of the steps of which is detailed below.

[0081] During a step E10, a target pressure P4 is determined in the cruise phase. The target pressure P4 may, for example, correspond to the pressure requirement of the aircraft in the cruise phase.

[0082] During a step E11, the upstream port 3 is positioned in the compression section, for example in the high-pressure compressor 5, so that the pressure at the upstream port 3 is equal to the target pressure P4 in the cruise phase. The pressure levels at each stage of the high-pressure compressor 5 are mapped precisely, by ground tests or by calculations, in order to evaluate the pressure levels for all operating conditions of the turbomachine 1.

[0083] An example of upstream port positioning from the sizing process is illustrated in Figure 3b.

[0084] Furthermore, the above method makes it possible to size the upstream port but also the HP 21 and LP 31 converters and the electrical power modules 22, 32, knowing the rotation speed at the take-off and climb speeds of the high pressure shaft 12 and the low pressure shaft 11.

Claims

CLAIMS 1. Set of a turbomachine (1) comprising: - a high pressure compressor (5) configured to be driven by a high pressure shaft (12); - a low pressure compressor (4) configured to be driven by a low pressure shaft (11), the low pressure shaft (11) being configured to be driven at a lower speed than the high pressure shaft (12); - a first power converter (21) configured to be driven by the high pressure shaft (12); - an air circulation system comprising a first air sampling port (9) positioned in the high pressure compressor (5) and a second air sampling port (3) placed upstream of the first air sampling port (9); - means for determining an operating condition (50) of the turbomachine assembly (1); and - a controller (40) configured to send instructions to transfer to the first power converter (21) a power from the high pressure shaft (12) to the low pressure shaft (11) or a power from the low pressure shaft (11) to the high pressure shaft (12) depending on the operating condition.

2. Assembly according to claim 1, in which the means for determining the operating condition (50) comprise at least one of the following elements: - a pressure sensor positioned at the second air sampling port (3); - a calculator configured to estimate a pressure at the second air sampling port (3).

3. Assembly according to one of claims 1 and 2, in which the first power converter (21) is an electromechanical converter operating in generator mode, the first power converter (21) being able to take power from the high pressure shaft (12) or transfer power to the high pressure shaft (12).

4. Assembly according to one of claims 1 to 3, further comprising a second power converter (31) receiving the power from the first power converter (21), the second power converter (31) being able to take the power from the low pressure shaft (11) or transfer the power to the low pressure shaft (11).

5. Assembly according to claim 4, in which the second power converter (31) is an electromechanical converter operating in motor mode.

6. Assembly according to one of claims 1 to 5, in which the second air sampling port (3) is positioned in the high pressure compressor (5).

7. Assembly according to one of claims 1 to 6, in which the high pressure compressor (5) comprises a given number of compression stages, the second port (3) being positioned between the second stage and the fourth stage, preferably between the second stage and the third stage.

8. Turbomachine (1) comprising an assembly according to one of claims 1 to 7.

9. Method for controlling (EO) a turbomachine assembly (1) according to one of claims 1 to 7, comprising the following steps: - determine (E1) an operating condition of the turbomachine assembly (1); and - transferring (E2) a power from the high pressure shaft (12) to the low pressure shaft (11) or a power from the low pressure shaft (11) to the high pressure shaft (12) depending on the operating condition so as to increase a pressure at the second sampling port (3).

10. Method for dimensioning (E10) a turbomachine assembly (1) according to one of claims 1 to 7, comprising the following steps: - determine (E11) a target pressure (P4) in the cruising phase of the turbomachine (1); and - position (E12) the second sampling port (3) so that the pressure at the second sampling port (3) is equal to the target pressure (P4).

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