FR3094029A1 - Turbomachine adapted for improved cleaning and method of cleaning turbomachine - Google Patents

Abstract

The invention relates to a computer of a turbomachine, the computer comprising a module for controlling unloading valves of the turbomachine, the module for controlling unloading valves being configured to operate selectively in a normal operating mode and in a mode of operation. cleaning operation, said control module being configured to switch from normal operating mode to cleaning operating mode when a cleaning operating mode activation command and a cleaning operating mode unlocking command are activated, and being configured to control, in the cleaning operating mode, the at least partial closing of the unloading valves and preferably the at least partial closing of the sampling valves, to allow confinement of cleaning fluids in a primary stream of the turbomachine. Figure for the abstract: Fig. 3

Description

Turbomachine adapted for improved cleaning and method of cleaning turbomachine

The invention relates to the maintenance of turbomachines. The invention relates more particularly to a turbomachine regulation system allowing improved cleaning of the turbomachine as well as to an improved cleaning method.

A turbomachine with double flow and double body has a primary stream in which circulates a primary flow. The primary flow is compressed by a low pressure compressor and a high pressure compressor, then is burned within the combustion chamber and sets in motion a high pressure turbine and a low pressure turbine. The turbomachine also has a secondary vein which surrounds the primary vein.

The components of the turbomachine exposed to the air flow can become clogged during the operation of the turbomachine. Indeed, the incoming air can carry particles likely to adhere to the contact surfaces, for example dust. This phenomenon is known as “fouling”.

In the absence of cleaning, the particles thus ingested form an increasingly thick layer, for example on the blades of compressors and turbines. Fouling therefore compromises the aerodynamic performance of the turbomachine, in terms of mass flow and energy efficiency of the compressors.

Fouling also has a significant environmental impact, since it increases fuel consumption and amplifies the negative effects related to the heat of the exhaust gases.

Consequently, a cleaning operation inside the turbomachine is usually provided for in the maintenance cycles. We also speak of “water wash”, according to current terminology, for this maintenance operation. A simple water wash method consists of bringing cleaning water inside the turbomachine using pipes.

Cleaning fluids can be ingested into the primary and secondary veins at the air inlet. However, cleaning fluids ingested in the primary vein can escape into the secondary vein.

This results in less efficient deslagging of the compressors, turbines and combustion chamber, with a possible increased consumption of cleaning fluids and a lengthening of the water-wash time.

To overcome this problem, it has been proposed to ingest the cleaning fluids directly in the vicinity of the internal organs to be cleaned, for example in front of the compressors. It has thus been proposed to spray cleaning fluids at the compressor blades.

However, this complicates the architecture of the cleaning systems and increases the size and the mass not useful for propulsion.

GENERAL PRESENTATION OF THE INVENTION

There is therefore a need for improved cleaning of the internal organs of a turbomachine, in particular of the primary vein.

There is an additional need for a simple cleaning solution that does not increase the size or mass of the turbomachine.

Subsidiarily, a cleaning solution is sought which reduces the downtime of the aircraft comprising the turbomachine, the water-wash maintenance being usually carried out in a cleaning center.

As such, the invention relates according to a first aspect to a computer of a turbomachine, the computer being programmed with code instructions to control the turbomachine,

the computer comprising a turbine engine unloading valve control module, the unloading valve control module being configured to operate selectively in a normal operating mode and in a cleaning operating mode,

said control module being configured to switch from the normal operating mode to the cleaning operating mode when a cleaning operating mode activation command and a cleaning operating mode unlocking command are activated,

and being configured to control, in the cleaning mode of operation, the at least partial closing of the unloading valves, and preferably the at least partial closing of the take-off valves of the turbomachine, to allow containment of cleaning fluids in a stream turbomachine primary.

The engine computer of the invention comprises a control module for the unloading valves, for example the VBV and HBV valves at the level of the compressors, capable of operating according to two distinct modes, a normal operating mode and a cleaning operating mode. The at least partial closing of the unloading valves during the cleaning operations makes it possible to prevent the uncontrolled leakage of cleaning fluids through said valves.

The cleaning fluids are retained in the primary stream and the cleaning of the engine components present in the primary stream (in particular the compressors, the combustion chamber and the turbines) is thus improved.

In addition, the cleaning operating mode is activated if both the activation command and the unlocking command are activated in the computer. The need for an unlocking command makes it possible to control the activation of the cleaning operating mode and the selective and voluntary closing of the unloading valves. In particular, this prevents the valves from being closed following a malicious act, or at a time when the operational conditions are not conducive to the water-wash operation.

Optionally and without limitation, a computer of the invention may have the following characteristics taken alone or in any of their technically possible combinations:

- the control module is configured to control, in the cleaning operating mode, the total closing of the unloading valves;

- the unloading valves comprise at least a first unloading valve between a low pressure compressor and a high pressure compressor of the turbomachine, and/or at least a second unloading valve between the high pressure compressor and a combustion chamber of the turbomachine ;

- the computer comprises an activation interface configured to receive the cleaning mode activation command via a communication network and/or from an actuator, for example a switch located in the cockpit;

the computer is configured to determine an activated or deactivated state of the cleaning operating mode activation command according to a fouling indicator of the turbomachine and/or according to environmental conditions, preferably weather conditions;

- the computer comprises an unlocking interface adapted to receive an unlocking signal from an aircraft cockpit actuator.

- the computer being configured to determine an activated or deactivated state of the unlocking command as a function of one or more parameters taken from the following list: an altitude of an aircraft containing the turbomachine, a connected or unconnected state of a cleaning device, a signal that an aircraft containing the turbine engine is resting on landing gear, a recommendation to clean the turbine engine, environmental and preferably weather conditions;

- the computer further comprises a control interface for a combustion chamber of the turbomachine, configured to control the extinction or maintenance in the off position of the combustion chamber in a chamber off sub-mode of the cleaning operating mode , and a control interface for a fan of the turbomachine configured to control a slow ventilation rotation of the fan in the chamber-off sub-mode;

- the combustion chamber control interface is configured to control the combustion chamber to be ignited or kept in the ignited position in a chamber-on sub-mode of the cleaning operating mode, and to control a normal rotation of the blower in the chamber-on sub-mode,

- the computer can then be configured to raise the temperature of the turbomachine, in the sub-mode with the chamber on, according to a pressure setpoint and a predetermined temperature setpoint;

- the computer can then be configured to partially open the wastegates in order to respect the temperature and pressure setpoints in the combustion chamber of the turbomachine, to be able to maintain the chamber-on sub-mode while maximizing ingestion liquid in the chamber;

- the computer is configured to control a first turbine engine of an aircraft and to operate jointly with a second computer configured to operate a second turbine engine of the aircraft.

The invention relates, according to a second aspect, to a turbomachine comprising a computer as defined above.

The invention also relates, according to a third aspect, to a method for cleaning a turbine engine of an aircraft, the turbine engine comprising unloading valves, the method comprising the steps of:

- detection of an activated state of a cleaning mode activation command,

- detection of an activated state of a cleaning mode unlocking command,

- switching from a normal operating mode to a turbomachine cleaning operating mode,

- at least partial closure of the unloading valves,

- ingestion of cleaning fluids in a primary stream of the turbomachine.

This method can be implemented via a turbomachine computer as defined above.

A method of the invention may also have the following non-limiting characteristics, taken alone or in combination:

- during the ingestion of the cleaning fluids, a filtering of the waste water resulting from the circulation of the cleaning fluids is carried out;

- the method comprises an additional step of connecting a cleaning device to the turbomachine, the cleaning device injecting, during the ingestion step, cleaning fluids into the primary vein;

- the cleaning fluid is rainwater, said rainwater being ingested from an environment external to the aircraft.

GENERAL PRESENTATION OF FIGURES

Other characteristics, aims and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, accompanied by the appended drawings, among which:

Figure 1 is an overall diagram of a turbofan engine;

Figure 2 shows the elements of a turbine engine and a cleaning system;

FIG. 3 is a block diagram of the regulation logic of a computer according to a first embodiment of the invention;

FIG. 4 schematically represents the steps of a turbomachine cleaning method according to one embodiment of the invention;

Figure 5 is a representative diagram of a primary stream and a secondary stream of a turbomachine equipped with the computer of Figure 3, during cleaning;

FIG. 6 is a block diagram of the regulation logic of a computer according to a second embodiment of the invention;

FIG. 7 is a block diagram of the regulation logic of a computer according to a third embodiment of the invention;

Figure 8 schematically represents the steps of a turbomachine cleaning method according to another embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In the computer examples presented below, the unloading valve control module is able to control a level of closure of the VBV valves (for "Variable Bleed Valve") located between the low pressure compressor and the high pressure compressor, and HBV valves (for "Handling Bleed Valve") located between the high pressure compressor and the combustion chamber.

A VBV valve is used to deflect air between the compressors and an HBV valve is used to take air from the high pressure compressor outlet to discharge said air into the primary stream or into the secondary stream. These two types of valves are positioned in the intermediate casing.

However, the invention can be applied with the same advantages for closing other valves located on the passage of cleaning fluids during water wash operations.

Throughout the following, similar elements in the appended figures are designated by the same reference numerals.

Turbomachine and cleaning system

There is shown schematically in Figure 1 an upper half of a twin body turbomachine and turbofan of an aircraft.

The turbomachine 1 has, from upstream to downstream along the axis X of the turbomachine in the direction of gas flow, a fan 2, a low pressure (or LP) compressor 3, a high pressure (or HP) compressor 4 , a combustion chamber 5, a high pressure turbine 6, and a low pressure turbine 7.

A primary vein which includes compressors 3 and 4, combustion chamber 5 and turbines 6 and 7 extends downstream of the fan. A secondary vein extends around the primary vein, also downstream of the fan. The primary stream and the secondary stream are separated by an intermediate casing. Also shown is an air inlet 8 of the turbomachine.

In a known manner, each of the compressor and turbine stages consists of a moving member (rotor) and a fixed member (rectifier). The fixed and moving parts of compressors and turbines include blades.

The useful surfaces of the blades are in direct contact with the air flows passing through the inlet 8. When air laden with dust or laden with other particles in suspension is admitted into the engine, a fouling phenomenon may occur. produce, particularly in the combustion chamber and on the blades of compressors and turbines.

In what follows, turbomachine regulation logic adapted for the regular implementation of cleaning processes (also called water wash) will be described in order to return as close as possible to the state of the turbomachine before fouling. One objective of these cleaning operations is to restore the performance of the turbomachine.

FIG. 2 shows functional elements of the turbine engine 1 as well as a cleaning system 34 and controls 30 for piloting and maintenance. The controls 30 are located either in the piloting zones of an aircraft which contains the turbine engine, such as the cockpit, or on an external part of the turbine engine.

The turbomachine comprises an engine computer 10. In what follows, the computer 10 is a full authority regulator, commonly known by the name of FADEC, for “Full Authority Digital Engine Controller”, located at the interface of the turbomachine with the cockpit of the aircraft. The computer 10 has in particular the functions of monitoring the operational conditions of the engine (temperatures of the engine components, speeds of the rotating elements, etc.) and of regulating the engine accordingly.

However, the control logics and cleaning processes described below can be applied with the same advantages for other types of computer.

The computer 10 communicates with actuators 21 capable of controlling a propulsion system 20.

The computer 10 is also connected to sensors 33 capable of measuring operational parameters of the propulsion system. The sensors 33 may in particular comprise one or more exhaust gas temperature sensors, or EGT sensors.

Finally, the computer 10 communicates with unloading valves 22 of the turbomachine. The unloading valves 22 comprise VBV valves (for "Variable Bleed Valve") located between the low pressure compressor and the high pressure compressor, and HBV valves (for "Handling Bleed Valve") located between the high pressure compressor and the chamber burning.

Unloading valves ensure the aerodynamic stability of the compressors. By way of example, the VBV and/or HBV valves can be opened to evacuate air flows at the outlet of the compressors, in order to avoid a surge phenomenon at the level of the compressors and a possible stall, in particular in the event of a change of engine speed.

The turbomachine also includes sampling valves (not shown in the figure). For example, an air bleed valve can be located near the low pressure compressor in the primary duct. In addition, the turbomachine comprises bleed valves for the thermal control of the clearances at the level of the low pressure and high pressure turbines, in order to cool the casings and the blades of said turbines. For electronic communication with the unloading valves, the computer 10 comprises a module 12 for controlling unloading valves. Through module 12, the computer can transmit instructions to open or close the unloading valves and possibly receive in real time signals measuring the position of the unloading valves.

To ensure the regulation of the engine, the computer 10 comprises a memory on which code instructions of a regulation software 11 are recorded. A logic for regulating the turbomachine and in particular for regulating the actuators 21 and the valves 22 is encoded in the control software.

The computer further comprises modules (not shown) for controlling the actuators 21, in particular a fan control module and a combustion chamber control module.

The computer also includes an interface 13 for activating a cleaning operating mode and an interface 14 for unlocking said cleaning operating mode, the roles of which will be indicated in detail below.

The piloting and maintenance controls 30 include a control device for activating a cleaning operating mode of the computer 10.

The activation control device can comprise a control panel 32 (not represented in FIG. 2) located in the cockpit of the aircraft, for example at the level of a man-machine interface located in the cockpit, and/or comprise a control panel 31 (not represented in FIG. 2) located directly at the level of the turbomachine, for example at the level of a nacelle hatch of the turbomachine.

The piloting and maintenance controls further comprise a cleaning mode deactivation control device, preferably located close to the activation controls, at least as easily accessible as the activation controls.

Preferably, the activation and/or deactivation commands are accompanied by luminous indicators, readable and operable in any lighting condition, to indicate an activated or deactivated state of the cleaning operating mode of the computer 10.

Alternatively, a remote cleaning mode activation and/or deactivation control device can be used, such as a computer or a mobile terminal capable of communicating with the computer via a wireless communication network, which can be remote from the turbomachine.

The cleaning system 34 is not described in detail here. Any known cleaning device can be used for turbomachine water wash operations, for example a nozzle positioned close to the air inlet of the turbomachine, capable of injecting cleaning fluids (typically water) into the primary vein and the secondary vein. Optionally, a pipe for recovering cleaning fluids is added at the outlet of the turbomachine, capable of recovering the fluids after they have passed through the primary stream and/or the secondary stream.

It is also possible to provide a wired or wireless link between the computer 10 and the cleaning system 34 to allow the cleaning system to communicate an activated or deactivated state of the cleaning system and/or a connected or unconnected state to the turbomachine. for a cleaning nozzle.

Cleaning the turbomachine on the ground – First regulation logic

FIG. 3 schematically represents a regulation logic according to a first embodiment of the invention. This control logic, as well as the alternative control logics which will be presented below, can be programmed digitally in the control software 11 of the computer 10 to allow improved management of the cleaning operations.

Alternatively, these control logics can be programmed electronically, using logic gates.

In accordance with the invention, the computer 10, more specifically a control module 12 of the HBV and VBV valves, is programmed to operate selectively in a normal operating mode and in a cleaning operating mode.

The cleaning operating mode differs from the normal operating mode by a different control law for the unloading valves 22, in particular HBV and VBV. When the cleaning mode of operation is activated, the unloading valves are kept at least partially closed (except, advantageously, in the event of an emergency requiring the valves to be opened, for example if a compressor surge is imminent) .

For example, a fully open position of a VBV unloading valve can correspond to a 20° angular position of a gate of the valve, and a fully closed position can correspond to a 0° angular position.

In the control of the prior art, the cleaning was carried out with open unloading valves and corresponded to a rest mode or a low speed mode of the motor control logic. Preferably, in the cleaning operating mode, the module 12 controls the total closing of said valves 22.

The at least partial closure of the valves 22 allows confinement of cleaning fluids in the primary stream of the turbomachine. By fluid confinement, it is meant that the proportion of the flow of cleaning fluids which escapes from the primary stream, between the inlet of the primary stream and the outlet of the primary stream, is less compared to the case where the valves 22 are in the open position.

In this embodiment, as well as in the other embodiments below, of the valves 22, the computer is programmed to switch the control module 12 between the normal operating mode and the cleaning operating mode.

By “normal operating mode” is meant an operation where the turbomachine control options are not limited due to the fact that cleaning operations would be in progress.

The activated or deactivated state of the cleaning operating mode results, for example, in a state of 0 or 1 of a corresponding variable.

• Une commande d’activation CA du mode nettoyage activée, c’est-à-dire en mode ON ;
• Une commande de déverrouillage CD du mode nettoyage activée, c’est-à-dire en mode ON.

The cleaning operating mode, which corresponds to an exceptional case, is activated if the computer jointly detects:

• A cleaning mode AC activation command activated, i.e. in ON mode;
• A cleaning mode CD unlock command enabled, i.e. in ON mode.

If either of these controls is in OFF mode, it remains or goes to normal operating mode.

With regard to the AC activation command, its ON or OFF state depends on the reception of activation signals by the activation interface 13 of the computer.

The activation signals come from the piloting and maintenance controls 30. Thus, an activation signal is sent either from the control panel 31 located on the turbine engine, typically by a maintenance technician, or from the control panel 32 from the cockpit, typically by a pilot or co-pilot. An activation signal can also be received from a device owned by the pilot or a maintenance operator, via a communication network.

Alternatively, the activation command can be activated automatically by the computer if an indicator representative of the fouling state (the fouling state), such as the EGT margin, for example, is beyond a predetermined threshold. .

When the AC enable command is activated, the AC enable command will go to the ON state, either until a disable command is detected or for a predetermined duration.

With regard to the CD unlocking control, its ON or OFF state depends on the one hand, on an unlocking authorization by the pilot or the co-pilot, and on the other hand, on the detection of conditions conducive or not to operations. of cleaning, the two conditions being cumulative.

The authorization of the unlocking of the cleaning operating mode by the control team is done using the control panel 32, for example via a switch.

The unlocking of the cleaning mode being a sensitive step in terms of safety, this unlocking is preferably conditioned by the authentication of the pilot to electronically validate the procedure, via the man-machine interface present in the cockpit, for example via a pilot code or via biometric authentication, and/or by flipping a protected switch.

If the aircraft is on the ground, the unlocking authorization is preferably carried out by the captain, the co-pilot or a maintenance operator.

If the aircraft is in flight at the time of the unlocking authorization, this authorization is preferably activated for a limited time (for example from 10 to 60 seconds, or from 1 to 10 minutes), so as to ensure that the transition to the cleaning mode of operation cannot take place long after clearance by the flight personnel. This makes it possible to reinforce security against malicious acts.

In addition, for the aircraft in flight, the unlocking control CD is preferably automatically switched back to the OFF state at the start of takeoff.

The detection of conditions favorable to cleaning advantageously comprises the detection of a parameter or any combination of parameters among the following:

- an altitude of the aircraft,

- a connected or unconnected state of the cleaning system 34,

- a signal that the aircraft is resting on its landing gear,

- a recommendation to clean the turbomachine, for example with regard to the EGT margin detected.

These parameters are detected by one or a series of sensors 33.

In the embodiment of Figure 3, the computer 10 is programmed for an activation of the cleaning operating mode while the aircraft is positioned on the ground.

Thus, in the cleaning operating mode, the computer is programmed so that a flight cycle phase is not possible.

Alternatively, the cleaning operating mode has a chamber off sub-mode and a chamber on sub-mode, depending on whether or not the combustion chamber is burning gas.

In the chamber-off sub-mode, a combustion chamber control interface controls the extinguishing or the maintenance in the off position of the combustion chamber.

Preferably, in the chamber off submode, the unloading valves are fully closed. If the control logic of the computer also provides for the closing of sampling valves, these latter valves are also completely closed in this sub-mode.

Preferably, in the chamber off sub-mode, the fan is still rotated via the fan control interface. This "slow ventilation" mode is provided for in the classic regulation of actuators during the following phases: ventilation (before a start-up or during a start-up), start-up, taxi-in (to avoid the installation of thermal imbalances after stopping the the turbomachine).

If the aircraft is in flight, the fan can be driven in rotation by "wind-milling", the relative wind driving the turbine engine blades.

Slow ventilation is controlled by the electric or pneumatic starting device, for example by the auxiliary unit or APU (“Auxiliary Power Unit”). By means of the power transmission members, the high-pressure body of the turbomachine is driven in rotation.

One advantage of slow rotation is to prevent the installation of thermal imbalances and/or thermal deformations during the cooling of the turbomachine after its extinction, which makes it possible to consider the activation of the cleaning operating mode shortly after the end of a flight cycle.

An advantage of the slow rotation during the cleaning mode of operation is to increase the ingestion of air and cleaning fluids and to increase the stripping force compared to cleaning without rotation, the fluids also being evacuated by entrainment in addition to gravity. An advantage of the chamber-off sub-mode is that it does not consume fuel or generate thrust to counter. In the chamber-on sub-mode, a combustion chamber control interface controls the ignition or the keeping the combustion chamber in the lit position.

Provision may be made for the unloading valves to remain partially open in the chamber-on cleaning sub-mode, in order to allow compliance with the temperature and pressure setpoints. If the control logic of the computer also provides for the closing of sampling valves, these latter valves are also preferably partially open in this sub-mode.

One benefit of the fired chamber sub-mode is to increase the ingestion of air and cleaning fluids and increase the stripping force compared to slow rotation. The duration of the water wash operations is therefore reduced. Another interest is to allow selective vaporization of cleaning fluids, some fluids having better cleaning properties in the gaseous state.

Figure 4 represents the steps of a cleaning process (or water wash) on the ground of the turbomachine comprising the computer with the regulation logic of Figure 3. It comprises steps of:

- installation E1 of the cleaning system 34,

- detection E2a of an activated ON state of the AC activation command,

- detection E2b of an activated ON state of the CD unlocking command, before, after or simultaneously with detection E2a,

- passage E3 from the normal operating mode to the cleaning operating mode, once the CA and CD commands have been detected in the ON state,

- at least partial closure E4 of the unloading valves 22,

- ingestion E5 of cleaning fluids within the primary stream and/or the secondary stream, by launching the cleaning system 34, and cleaning the interior of the turbomachine, this cleaning possibly taking place in the sub-mode at chamber off or chamber on sub-mode as described above.

The cleaning process can then be stopped by implementing steps of:

- E6 extinction of the cleaning system 34,

- detection E7 of a cleaning mode deactivation command (activation command and/or unlocking command OFF),

- E8 switch to normal operating mode.

Depending on the state of the turbomachine when returning to the normal operating mode, the unloading valves 22 can remain closed or else be open, since their open or closed state is no longer limited in the normal operating mode.

In addition, during the cleaning operation, during the circulation of the cleaning fluids, filtering of the waste water can advantageously be carried out, for example at the outlet of the primary conduit.

Optionally, the sampling valves located in the primary conduit are also at least partially closed.

There is shown in Figure 5 the primary stream 9a and the secondary stream 9b of the turbomachine during the cleaning step E5.

The entry of the cleaning fluids through the air inlet is represented by the reference F. The flow of cleaning fluids is divided downstream of the fan between the flow Fa circulating in the primary stream 9a and the flow Fb circulating in the secondary vein 9b.

An advantage of the closed state of the VBV 23 and HBV 24 valves is to increase the proportion of the flow Fa compared to the flow Fb.

This significantly improves the cleaning of the internal parts of the turbomachine, in particular the compressors 3 and 4, the combustion chamber 5 and the turbines 6 and 7.

This makes it possible to optimize cleaning operations and reduce the downtime of the aircraft on the ground for cleaning operations, while maintaining good cleaning efficiency.

Cleaning the turbomachine in flight – Second control logic

FIG. 6 schematically represents a regulation logic according to a second embodiment.

As before, the computer selectively switches the module 12 for controlling the unloading valves 22 between a normal operating mode and a cleaning operating mode. The cleaning operation mode is activated if the AC enable command and the CD unlock command are in the ON state. If one of the two controls goes to the OFF state, it remains or goes to normal operating mode.

In the mode of Figure 6, the cleaning operating mode can be activated while the aircraft is in flight, and while the regulation of the turbomachine corresponds to a flight phase (for example a cruising phase).

In addition, the activation command and the unlock command are generated by the cockpit control panel 32.

The CA activation command, received by the activation interface 13, can be activated, as seen previously, by the pilot. Preferably, in order to guarantee a high level of safety for the transition to the cleaning operating mode, the transition to the ON state of the AC activation command requires simultaneous confirmation from the pilot and the co-pilot. For example, individual keys must be turned simultaneously by the pilot and co-pilot in switch locks in the cockpit control panel.

With regard to the CD unlocking command, activation by the pilot (and/or the co-pilot) and conditions conducive to the cleaning operating mode, here in flight, are required.

Advantageously, the unlocking command CD is in the ON state at the unlocking interface 14 if a cleaning recommendation for the turbomachine is activated (for example in view of the level of the EGT margin) and if the environmental conditions, preferably meteorological, are favorable. Under these conditions, the unlocking interface 14 generates a signal for the attention of the piloting team according to which the cleaning operating mode can be unlocked.

Very advantageously, rainwater is used as the cleaning fluid when the cleaning operating mode is activated during flight. It is either rain from ongoing precipitation or rainwater contained in clouds outside of any precipitation. In this case, it is not necessary to connect a cleaning system 34 to the turbomachine. a cleaning system outside the turbomachine.

However, the ingestion time is preferably limited to meet the engine operation certification time delays while avoiding inducing additional safety risks.

“Favorable environmental conditions” then means that the level of precipitation is sufficient. This information is given to the computer 10 by sensors 33 of the turbomachine, or alternatively via a communication network conforming to aeronautical safety standards (satellite, encrypted Internet, etc.).

The path of the aircraft during flight can be adjusted to expose the aircraft longer to rainwater. Clouds containing rainwater are typically located at an altitude lower than the usual altitude of the aircraft during the cruise phase. It is therefore possible to prolong the passage of the aircraft in the clouds during the climb and descent phases.

When the cleaning mode of operation is activated, as for the mode of Figure 3, the unloading valves are maintained at least partially closed (except, advantageously, in the event of an emergency requiring the opening of the valves, for example example if compressor surge is imminent).

As before, there is advantageously a chamber-on sub-mode and a chamber-off sub-mode.

These two sub-modes are shown at the bottom of Figure 6. The chamber-off sub-mode, during aircraft flight, corresponds to an IFSD (“In-Flight Shut Down”). The computer is configured so that this sub-mode is only activated if the aircraft has at least one second operational turbine engine and not in the cleaning operating mode. Preferably, air traffic control must be informed of the IFSD procedure commanded and authorize the operation.

In the chamber-on sub-mode, the unloading valves (e.g. HBV and VBV) being closed during flight, the ingestion of cleaning fluids must be carefully controlled in order to maintain the usual pressure and temperature margins. The usual "Engine Monitoring" function of the computer, and in particular the pressure and temperature set point for the engine temperature rise, are preferably adapted according to the quantity of cleaning fluids ingested to ensure compliance with the pressure margins and temperature.

The unloading valves can then be partially opened in order to respect the pressure and temperature set point, to be able to keep the chamber lit by maximizing the ingestion of liquid in the chamber, or to bail out as needed.

The in-flight cleaning operation, however, sacrifices the performance of the turbomachine momentarily, to allow the restoration of performance over the long term.

There is shown in Figure 7 a control logic of the engine computer according to a variant of Figure 6, still for the case of a cleaning operation during flight.

The characteristics of the logic in Figure 6 are repeated, with the exception of the management of the CD unlocking command. This command is determined autonomously by the computer unlocking interface 14: there is no need for unlocking confirmation by the pilot and/or the co-pilot.

In this variant, the piloting team always intervenes to switch the AC activation command to the ON state, but the switching of the CD unlocking command to the ON state is automatic.

The criteria for determining unlock (cleaning recommendation, favorable environmental conditions) are unchanged.

The possibility of activating the cleaning mode of operation during the flight of the aircraft, permitted by the regulation logics of Figures 6 and 7, has several advantages.

The cleaning operations are programmable in flight, so that the aircraft does not necessarily undergo ground immobilization in order to carry out the restoration of performance by water wash.

Conducting the in-flight water wash operation thus makes it possible to reduce the ground maintenance time of the aircraft, which facilitates the management of the air fleet and allows the aircraft to be used to its full potential.

The unloading valves remaining closed at least partially, the cleaning fluid reaches, as before, the organs inside the turbomachine and in particular the compressors, the turbines, the combustion chamber.

Furthermore, the regulation logics of Figures 6 and 7 make it possible to obtain the aforementioned advantages without sacrificing the safety of operations. Account is taken, in regulating the turbomachine, of the fact that the unloading valves are closed during flight.

Figure 8 represents the steps of a method for cleaning the turbine engine in flight comprising the computer with the regulation logic of Figure 6 or Figure 7, in which rainwater is used as cleaning fluid in flight, with stages of:

- detection E1bis that the level of precipitation exceeds a predetermined threshold authorizing cleaning by rainwater,

- detection E2a of an activated ON state of the AC activation command,

- detection E2b of an activated ON state of the CD unlocking command, before, after or simultaneously with detection E2a,

- passage E3 from the normal operating mode to the cleaning operating mode, once the CA and CD commands have been detected in the ON state,

- at least partial closure E4 of the unloading valves 22, and cleaning by ingestion of rainwater, this cleaning being able to take place in the sub-mode with the chamber off or in the sub-mode with the chamber on as described above .

The cleaning process can then be stopped with steps of:

- optionally, detection E6bis that the level of precipitation has fallen below the predetermined threshold,

- detection E7 of a cleaning mode deactivation command (activation command and/or unlocking command OFF),

- E8 switch to normal operating mode.

Depending on the state of the turbomachine when returning to the normal operating mode, the unloading valves 22 can remain closed or else be open, since their open or closed state is no longer limited in the normal operating mode associated normal regulation logics.

Optionally, the sampling valves located in the primary conduit are also at least partially closed.

In addition, during the cleaning operation, during the circulation of the cleaning fluids, filtering of the waste water can advantageously be carried out, for example at the outlet of the primary pipe.

Optionally, an automatic application of the brakes of the landing gear of the aircraft can be carried out during the cleaning process, or even a deployment of the airbrakes. An advantage is to compensate for the propulsive force exerted on the aircraft due to the ingestion of cleaning fluids with closed unloading valves. Landing gear chocks can be fitted for this purpose.

In addition, to avoid the ingestion of debris (or FOD for "Foreign Object Debris") or risks for the operators, a light signal visible from the outside of the turbine engine can be activated while the cleaning operating mode is active. , in particular to signal an on state of the chamber. Alternatively, the signaling used is audible.

Claims (15)

Computer of a turbomachine, the computer being programmed with code instructions to control the turbomachine,
the computer (10) comprising a module (12) for controlling unloading valves (22) of the turbine engine, the unloading valve control module being configured to operate selectively in a normal operating mode and in a cleaning operating mode ,
said control module being configured to switch from the normal operating mode to the cleaning operating mode when a cleaning operating mode activation command (CA) and a cleaning operating mode unlocking command (CD) are activated,
and being configured to control, in the cleaning mode of operation, the at least partial closing of the unloading valves (22) and preferably the at least partial closing of the take-off valves of the turbomachine, to allow containment of cleaning fluids in a primary stream (9a) of the turbomachine. Computer according to Claim 1, in which the control module (12) is configured to control, in the cleaning operating mode, the total closing of the unloading valves (22). Computer according to one of Claims 1 or 2, comprising an activation interface (13) configured to receive the cleaning mode activation command (CA) via a communication network and/or from an aircraft cockpit actuator . Computer according to one of Claims 1 or 2, the computer being configured to determine an activated or deactivated state of the cleaning operating mode activation command (CA) as a function of a fouling indicator of the turbomachine. Computer according to one of Claims 1 to 4, comprising an unlocking interface (14) adapted to receive the unlocking command (CD) from an aircraft cockpit actuator. Computer according to one of Claims 1 to 5, the computer being configured to determine an activated or deactivated state of the unlocking control (CD) according to one or more parameters taken from the following list:
- an altitude of an aircraft containing the turbine engine,
- a connected or unconnected state of a cleaning device,
- a signal that an aircraft containing the turbomachine is resting on landing gear,
- a recommendation to clean the turbomachine;
- environmental conditions, preferably meteorological conditions. Computer according to one of Claims 1 to 6, further comprising a control interface for a combustion chamber of the turbomachine, configured to control the extinction or maintenance in the off position of the combustion chamber in a sub-mode with the chamber switched off from the cleaning operating mode,
the computer further comprising a control interface for a fan of the turbomachine, configured to control a slow ventilation rotation of the fan in the sub-mode with the chamber off. Calculator according to claim 7, the combustion chamber control interface being configured to control the ignition or the maintenance in the on position of the combustion chamber in an on-chamber sub-mode of the cleaning operating mode,
the blower control interface being configured to control normal rotation of the blower in the chamber-on submode. Computer according to claim 8, configured to raise the temperature of the turbomachine, in the sub-mode with the chamber on, as a function of a pressure setpoint and a predetermined temperature setpoint. Computer according to one of Claims 1 to 9, configured to control a first turbine engine of an aircraft,
and configured to operate jointly with a second computer configured to operate a second turbine engine of the aircraft. Turbomachine comprising a computer according to one of claims 1 to 10. Method for cleaning a turbine engine of an aircraft, the turbine engine comprising unloading valves, the method comprising the steps of:
- detection (E2a) of an activated state of a cleaning mode activation command,
- detection (E2b) of an activated state of a cleaning mode unlocking command,
- switching (E3) from a normal operating mode to a turbomachine cleaning operating mode,
- at least partial closing (E4) of the unloading valves,
- ingestion (E5) of cleaning fluids within a primary stream of the turbomachine. Method according to claim 12, in which during the ingestion (E5) of the cleaning fluids, a filtering of the waste water resulting from a circulation of the cleaning fluids is carried out. Method according to claim 12 or 13, comprising an additional step of connecting (E1) a cleaning device to the turbine engine, the cleaning device injecting, during the ingestion step (E5), cleaning fluids into the primary vein. Method according to one of Claims 12 to 14, in which the cleaning fluid is rainwater, said rainwater being ingested from an environment external to the aircraft.