METHOD FOR FILLING A CLOSED CIRCUIT OF AN AIRCRAFT

Abstract

Method for filling a closed circuit (2) of an aircraft (3), the circuit (2) containing a fluid, the method being carried out by means of an assembly (1) comprising at least the closed circuit (2) and a tank (5) independent of the circuit (2), the tank (5) containing fluid intended for filling the circuit (2), the method chronologically comprising the steps of: a) determining the fluid mass of the MFC circuit when the fluid is at rest; b) comparing the fluid mass of the MFC circuit determined in step a) with a reference fluid mass MFR predetermined for the circuit (2); c) filling the circuit (2) with fluid until the fluid mass of the MFC circuit is equal to the reference fluid mass MFR, if the comparison carried out in step b) indicates that the fluid mass of the MFC circuit is less than the reference fluid mass MFR. Figure for abstract: 1

Description

Title of the invention: METHOD FOR FILLING A CLOSED CIRCUIT OF AN AIRCRAFT Technical field of the invention

[0001] The present invention relates to a method for filling a closed circuit of an aircraft and to an assembly intended for implementing this method. Technical background

[0002] An aircraft comprises different closed circuits each containing a fluid intended to fulfill a predetermined function.

[0003] The term "closed circuit" means a circuit in which the fluid returns to its starting point, and in other words a circuit in which the fluid circulates in a closed loop.

[0004] Cooling circuits (or cooling loops) are, for example, closed circuits in which heat transfer fluids circulate.

[0005] Such heat transfer fluids are used to transport or remove heat.

[0006] Over time and hours of operation, the amount of fluid contained in These circuits are decreasing. This is why regular maintenance operations are planned to refill them. Regular refills are essential to allow the circuits to operate efficiently.

[0007] Each closed circuit generally includes visual markers (or graduations) at the filling orifice, for example the “min” and “max” markers. These visual markers allow the operator to be guided on the quantity of fluid to be introduced into the circuit. In fact, the operator in charge of filling introduces fluid into the circuit until the fluid level in the circuit is between the “min” and “max” markers.

[0008] Such filling is not optimal.

[0009] Indeed, the fluids contained in these circuits are sensitive to the ambient environment in which the filling takes place, and in particular to the temperature and atmospheric pressure of the ambient environment.

[0010] For example, the density of a fluid varies significantly depending on its temperature, its temperature obviously depending on the temperature of the ambient environment in which the filling takes place.

[0011] Thus, for equal volume, the mass of fluid loaded into the circuit following filling varies from one ambient environment to another.

[0012] Too much on-board fluid mass represents an additional mass which is obviously detrimental to the aircraft's performance.

[0013] Too much on-board fluid mass can also be the cause of a overpressure within the circuit which is generally pressurized during operation.

[0014] Indeed, the aircraft may be required to perform flights between two opposite extreme environments, for example from a cold environment where the circuit has been filled to a hot environment. In the aforementioned example, the fluid will expand significantly during the flight, and possibly generate excess pressure within the circuit when it is in excess.

[0015] This possible overpressure requires aircraft / engine manufacturers to oversize the circuit accordingly, so that it can withstand such overpressure, particularly to the detriment of the mass and bulk of the circuit.

[0016] Conversely, an on-board fluid mass that is too low represents a risk of insufficient pressurization of the circuit, and therefore possible vaporization of the fluid. This vaporization can be harmful to certain equipment in the circuit.

[0017] The aforementioned drawbacks are all the more penalizing when the fluid has a high coefficient of expansion.

[0018] The objective of the present invention is therefore to provide a simple, effective and economical solution making it possible to respond to the aforementioned problem. Summary of the invention

[0019] The invention thus proposes a method for filling a closed circuit of an aircraft, the circuit containing a fluid, the circuit comprising at least one expansion tank, the method being carried out by means of an assembly comprising at least the closed circuit and a tank independent of the circuit, the tank containing fluid intended for filling the circuit, the method chronologically comprising the steps consisting of: a) determining the mass of fluid in the MFC circuit when the fluid is at rest; b) comparing the fluid mass of the MFC circuit determined in step a) with a predetermined reference fluid mass MFR for the circuit; (c) filling the fluid circuit until the fluid mass of the MFC circuit is equal to the reference fluid mass MFR, if the comparison made in step (b) indicates that the fluid mass of the MFC circuit is less than the reference fluid mass MFR.

[0020] Such a filling method makes it possible to load the same mass of fluid corresponding to the reference fluid mass MFR at each filling, the mass of fluid loaded thus no longer being dependent on the ambient environment in which the filling takes place. The risk of loading an excess or insufficient mass at filling is thus eliminated, which is obviously favorable to the efficiency of the aircraft.

[0021] Such a filling method makes it possible to size the circuit on the basis of the reference fluid mass MFR, it is thus not necessary to oversize the circuit to cope with possible overpressures, in particular to the benefit of the mass and bulk of the circuit.

[0022] The reference fluid mass MFR is a predetermined, optimized fluid mass specific to each circuit. This reference fluid mass MFR represents the mass of fluid that must be reached in the circuit after filling. This reference fluid mass MFR is defined to allow in particular efficient operation of the circuit during a predetermined period of time (equivalent for example to the period of time between two maintenance operations).

[0023] The method according to the invention may comprise one or more of the following characteristics and / or steps, taken in isolation from one another or in combination with one another: - step a) includes the sub-steps consisting of: al) measure the static pressure of the PSF fluid at a measuring point i of the circuit; a2) measure the ambient atmospheric pressure Paa; a3) measure the temperature of the fluid in the TFC circuit; a4) determining the mass of fluid in the MFC circuit from the static pressure of the fluid PSF which is measured in step a1), the ambient atmospheric pressure Paa which is measured in step a2) and the temperature of the fluid in the TFC circuit which is measured in step a3); - step c) includes the sub-steps consisting of: cl) measure the temperature of the fluid in the TFR tank; c2) determining a reference static pressure PSR at the measuring point i from the reference fluid mass MFR, the ambient atmospheric pressure Paa which is measured in step a2), the temperature of the fluid in the circuit TFC which is measured in step a3) and the temperature of the fluid in the reservoir TFR which is measured in step cl); c3) filling the fluid circuit until the static pressure of the fluid PSF at the measuring point i is equal to the reference static pressure PSR at the measuring point i which is determined in step c2), so that the fluid mass of the circuit MFC is equal to the reference fluid mass MFR; - the reference static pressure PSR at measuring point i is equal to the sum of the reference hydrostatic pressure PHR at measuring point i and the ambient atmospheric pressure Paa, the reference hydrostatic pressure PHR at measuring point i being determined from the following formula: [Math. 1] Pure = Pmp X g X hFR where pMP is the average density of the circuit fluid pFC and the reservoir fluid pFR which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in the circuit to obtain the reference fluid mass MFR, g is the acceleration of gravity of the ambient medium, and hFR is the reference fluid height in the circuit for the reference fluid mass MFR at an average temperature Tmp of the circuit fluid TFC and the reservoir fluid TFR which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in the circuit to obtain the reference fluid mass MFR; - the method comprises a step d) consisting of draining the circuit until the mass of fluid in the MFC circuit is equal to the mass of reference fluid MFR, if the comparison carried out in step b) indicates that the mass of fluid in the MFC circuit is greater than the mass of reference fluid MFR; - the closed circuit is a cooling loop containing a heat transfer fluid.

[0024] The present invention also relates to an assembly intended for implementing the method as described above, the assembly comprising: - a closed circuit containing a fluid, the circuit comprising at least one expansion tank; - a tank independent of the circuit, the tank containing fluid intended for filling the circuit; - a filling system comprising at least one pump configured to transfer fluid between the reservoir and the circuit; - a control device configured to control the filling system; - at least one first pipe connected to both the filling system and the tank; - at least one second line connected to both the filling system and the circuit; - a first pressure sensor measuring the static pressure of the PSF fluid at a measuring point i of the circuit; - a second pressure sensor measuring the ambient atmospheric pressure Paa; - a first temperature sensor measuring the temperature of the fluid in the TFC circuit; - a second temperature sensor measuring the temperature of the reservoir fluid T fr; the tank, the filling system and the first pipe forming part of airport equipment, and the closed circuit forming part of an aircraft.

[0025] The assembly according to the invention may comprise one or more of the following characteristics and / or steps, taken in isolation from one another or in combination with one another: - the closed circuit comprises at least one heat exchanger configured to allow a transfer of thermal energy between the fluid of the closed circuit and a second fluid of a second circuit; - the closed circuit is part of a propulsion unit of the aircraft; - the closed circuit is located in a nacelle of the propulsion group; - the closed circuit is a cooling loop containing a heat transfer fluid. Brief description of the figures

[0026] The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[0027] [Fig-1] [Fig.l] is a schematic view of an assembly according to a first mode of realization of the invention;

[0028] [Fig.2] [Fig.2] is a schematic view of an assembly according to a second mode of realization of the invention. Detailed description of the invention

[0029] In Figures 1 and 2 there is shown schematically an assembly 1 intended for filling a closed circuit 2 of an aircraft 3.

[0030] More specifically, as illustrated in Figures 1 and 2, the assembly 1 comprises: - the closed circuit 2 containing a fluid, the circuit 2 comprising at least one expansion vessel 4; - a tank 5 independent of circuit 2, the tank 5 containing fluid intended for filling circuit 2; - a filling system 6 comprising at least one pump 7 configured to transfer fluid between the reservoir 5 and the circuit 2; - a control device 8 configured to control the filling system 6; - at least one first pipe 9 connected both to the filling system 6 and to the tank 5; - at least one second pipe 10 connected both to the filling system 6 and to the circuit 2; - a first pressure sensor 11 measuring the static pressure of the fluid PSF at a measuring point i of the circuit 2; - a second pressure sensor 12 measuring the ambient atmospheric pressure Paa - a first temperature sensor 13 measuring the temperature of the fluid in the circuit T fc; and a second temperature sensor 14 measuring the temperature of the fluid in the TFR tank.

[0031] The tank 5, the filling system 6 and the first pipe 9 are part of airport equipment 15 and the closed circuit 2 is part of an aircraft 3.

[0032] Advantageously, the airport equipment 15 is a refueling vehicle (for example a refueling truck) comprising at least the tank 5, the filling system 6 and the first pipe 9.

[0033] Advantageously, the closed circuit 2 is part of a propulsion unit of the aircraft 3. The closed circuit 2 is located for example in a nacelle of the propulsion unit.

[0034] As indicated above, the term "closed circuit" means a circuit in which the fluid returns to its starting point, and in other words a circuit in which the fluid circulates in a closed loop.

[0035] Advantageously, the closed circuit 2 is a cooling loop containing a heat transfer fluid.

[0036] The closed circuit 2 contains a single fluid or a single fluid, preferably a fluid in the liquid state. The fluid may be capable of passing from a liquid state to a gaseous state (and vice versa) depending on the pressure and temperature to which it is subjected.

[0037] Advantageously, the closed circuit 2 comprises at least one heat exchanger (not shown) configured to allow a transfer of thermal energy between the fluid of the closed circuit 2 and a second fluid of a second circuit. The second circuit is for example a lubrication circuit for moving elements (such as bearings) of an engine of the propulsion group, this second circuit containing for example a liquid lubricant (for example oil).

[0038] The closed circuit 2 is pressurized, except during filling. When filling the circuit 2, the gaseous atmosphere of the expansion tank 4 is exposed to the open air, and in other words the gaseous atmosphere communicates with the ambient environment in which the filling takes place.

[0039] According to the first and second embodiments illustrated in Figures 1 and 2, the expansion tank 4 is located at a high end of the circuit 2. The expansion tank 4 here forms a fluid reservoir of the circuit. The expansion tank 4 makes it possible to absorb changes in volume of the fluid, linked in particular to changes in temperature. The first pressure sensor 11 and the first temperature sensor 13 are integrated into the circuit 2 and are located at a low end of the circuit 2. The measuring point i is thus located at the low end of the circuit 2.

[0040] According to an alternative embodiment, the expansion tank and the reservoir could be separate elements.

[0041] According to another embodiment variant, the first pressure sensor and / or the first temperature sensor could be integrated into the filling system.

[0042] The location of the measuring point i may vary, the measuring point i however necessarily being in contact with the fluid.

[0043] According to the first and second embodiments illustrated in Figures 1 and 2, the filling system 6 comprises a pump 7 configured to transfer fluid between the reservoir 5 and the circuit 2. The pump 7 is mechanically driven by a drive device (not shown) such as a thermal or electric motor. The sizing of the pump 7 and its drive device depends in particular on the location of the filling point 16 on the circuit 2, and more particularly on the height of the filling point 16, the height being defined along a vertical axis Z extending from the lower end of the circuit 2 to the upper end of the circuit 2. A low filling point 16 requires significant pressurization of the fluid to allow its introduction into the circuit. The filling system 6 further comprises an automated data processing unit 17, such as an industrial programmable logic controller. The automated data processing unit 17 is configured to implement the filling method explained in the remainder of the description.

[0044] The filling system 6 is controlled by the control device 8. The control device 8 here comprises a communication interface 18 allowing in particular an operator in charge of filling the circuit 2 to view the data (in particular the instructions and the information coming from the different sensors) and to control the filling system 6. The control device 8 is part of the airport equipment 15 and is independent of the filling system 6.

[0045] According to an alternative embodiment, the control device could be part of the filling system.

[0046] According to another variant embodiment, the control device could also be part of the aircraft, and more precisely of the propulsion unit of the aircraft (for example of the nacelle of the propulsion unit), in the case where the closed circuit is part of the propulsion unit of the aircraft.

[0047] According to the first and second embodiments illustrated in FIGS. 1 and 2, the second pressure sensor 12 and the second temperature sensor 14 are integrated into the filling system 6.

[0048] According to an alternative embodiment, the second temperature sensor could be integrated into the tank.

[0049] According to another embodiment, the second pressure sensor could be integrated into the tank or the circuit.

[0050] According to the first embodiment illustrated in [Fig.l], the second pipe 10 connecting the filling system 6 to the circuit 2 is connected to a filling orifice of the expansion tank 4, this filling orifice forming the filling point 16. Such a filling point 16 is said to be “dry” since it is not in contact with the fluid. During filling, the fluid from the tank is thus introduced into the circuit 2 via the filling orifice of the expansion tank 4. The filling orifice is located at the level of the gaseous headspace of the expansion tank 4. The pump 7 and its device drive are thus dimensioned to transfer fluid from the reservoir 5 to the filling orifice of the expansion tank 4. Such a filling point 16, located at a high end of the circuit 2, has the advantage of requiring a low-power drive device and pump 7, the filling being done simply by overcoming gravity.

[0051] According to the second embodiment illustrated in [Fig. 2], the second pipe 10 connecting the filling system 6 to the circuit 2 is connected to a filling point 16 of the circuit 2 located at the lower end of the circuit 2. Such a filling point 16 is said to be “wet” since it is in contact with the fluid. During filling, the fluid from the reservoir is thus introduced into the circuit 2 via the filling point 16. The pump 7 and its drive device are thus dimensioned to transfer fluid from the reservoir 5 to the filling point 16. Such a filling point 16, located at a lower end, has the advantage of being easily accessible, which is particularly advantageous in the case where the circuit is part of a large propulsion unit.However, such a filling point 16 requires a pump 7 and a drive device of greater power (compared to the first embodiment).

[0052] A wet filling point 16 also has the advantage of allowing a draining operation. The pump 7 here has two flow directions to allow both filling and draining operations.

[0053] The embodiments illustrated in the figures are in no way limiting, the filling point could be located at any point in the circuit. The pump and its drive device are in particular sized according to the height of the filling point on the circuit.

[0054] In the remainder of the description, we will focus more particularly on a filling method using an assembly comprising at least the closed circuit 2 and a reservoir 5 independent of the circuit, the reservoir 5 containing fluid intended for filling the circuit 2, the method chronologically comprising the steps consisting of: a) determine the mass of fluid in the MFC circuit when the fluid is at rest; b) comparing the fluid mass of the MFC circuit determined in step a) with a predetermined reference fluid mass MFR for circuit 2; c) filling circuit 2 with fluid until the mass of fluid in the MFC circuit is equal to the reference fluid mass MFR, if the comparison made in step b) indicates that the mass of fluid in the MFC circuit is less than the reference fluid mass MFR.

[0055] The filling method described above can be implemented by the assemblies 1 illustrated in Figures 1 and 2.

[0056] Advantageously, during step c), a predetermined tolerance (preferably, plus or minus 0.2 kilograms) is applied, the mass of fluid of the MFC circuit thus having to be equal to the mass of reference fluid MFR with a predetermined tolerance (preferably, plus or minus 0.2 kilograms).

[0057] A fluid is at rest when it is substantially motionless, its temperature and pressure being substantially stable.

[0058] The reference fluid mass MFR is a predetermined, optimized fluid mass specific to each circuit 2. This reference fluid mass MFR represents the mass of fluid that must be reached in the circuit 2 after filling. This reference fluid mass MFR is defined to allow in particular efficient operation of the circuit 2 during a predetermined period of time (equivalent for example to the period of time between two maintenance operations).

[0059] In the present application, the term “circuit fluid” means the fluid present in the circuit 2 and the term “reservoir fluid” means the fluid present in the reservoir 5 or the fluid coming from the reservoir 5.

[0060] Advantageously, the closed circuit 2 is part of a propulsion unit of the aircraft 3. The closed circuit 2 is located for example in a nacelle of the propulsion unit.

[0061] As indicated above, the term "closed circuit" means a circuit in which the fluid returns to its starting point, and in other words a circuit in which the fluid circulates in a closed loop.

[0062] Advantageously, the closed circuit 2 is a cooling loop containing a heat transfer fluid.

[0063] The circuit 2 contains a single fluid or a single fluid, preferably a fluid in the liquid state. The fluid may be capable of passing from a liquid state to a gaseous state (and vice versa) depending on the pressure and temperature to which it is subjected.

[0064] The closed circuit 2 is pressurized, except during filling. When filling the circuit 2, the gaseous atmosphere of the expansion tank 4 is exposed to the open air, and in other words the gaseous atmosphere communicates with the ambient environment in which the filling takes place.

[0065] Step a) may comprise the sub-steps consisting of: al) measure the static pressure of the PSF fluid at a measuring point i of circuit 2; a2) measure the ambient atmospheric pressure Paa; a3) measure the temperature of the fluid in the TFC circuit; a4) determining the mass of fluid in the MFC circuit from the static pressure of the fluid PSF which is measured in step a1), the ambient atmospheric pressure Paa which is measured in step a2) and the temperature of the fluid in the TFC circuit which is measured in step a3).

[0066] When the method is implemented by the assemblies 1 illustrated in Figures 1 and 2, the static pressure of the fluid PSF at the measuring point i is measured by the first pressure sensor 11 of assembly 1. The ambient atmospheric pressure Paa is measured by the second pressure sensor 12 of assembly 1. The temperature of the fluid in the TFC circuit is measured by the first temperature sensor 13.

[0067] Sub-step a4) may comprise the sub-sub-steps consisting of: a41) determine the fluid height h in circuit 2 from the following calculation: [Math. 2] u _ Psf " Paa°ù Psf is the static pressure of the fluid which is measured in step al), 11 " PFC xg Paa is the ambient atmospheric pressure which is measured in step a2), pFC is the density of the circuit fluid which is determined from the temperature of the circuit fluid TFC which is measured in step a3) via a relationship provided by the manufacturer and g is the acceleration of gravity of the ambient medium; a42) determining the volume of fluid in the VFC circuit from the fluid height h in the circuit 2 which is determined in sub-sub-step a41) and the temperature of the fluid in the TFC circuit which is measured in step a3) via an abacus expressing the volume of fluid in the VFC circuit as a function of the fluid height h in the circuit 2 and the temperature of the fluid in the TFC circuit; a43) determine the mass of fluid in the MFC circuit from the following calculation: [Math. 3] MFC = VFc x pFc where VFC is the volume of fluid in circuit 2 which is determined in sub-sub-step a42) and pFC is the density of the circuit fluid (determined from the circuit fluid temperature TFC which is measured in step a3) via a relationship provided by the manufacturer).

[0068] The abacus used in sub-sub-step a42) is defined for a given circuit having specific geometric and dimensional characteristics. In other words, the abacuses are distinct from one circuit to another.

[0069] The fluid height h corresponds to the vertical distance (distance defined along the vertical axis Z) between the measuring point i and the free surface of the fluid in the circuit 2.

[0070] Step c) may comprise the sub-steps consisting of: cl) measure the temperature of the fluid in the TFR tank; c2) determining a reference static pressure PSR at the measuring point i from the reference fluid mass MFR, the ambient atmospheric pressure Paa which is measured in step a2), the temperature of the fluid in the circuit TFC which is measured in step a3) and the temperature of the fluid in the reservoir TFR which is measured in step cl); c3) fill circuit 2 with fluid until the static pressure of the fluid PSF at measuring point i is equal to the reference static pressure PSR at measuring point i which is determined in step c2), so that the fluid mass of the MFC circuit is equal to the reference fluid mass MFR.

[0071] When the method is implemented by the assemblies 1 illustrated in FIGS. 1 and 2, the temperature of the fluid in the TFR tank is measured by the second temperature sensor 14.

[0072] The reference static pressure PSR at measuring point i is equal to the sum of the reference hydrostatic pressure PHR at measuring point i and the ambient atmospheric pressure Paa.

[0073] The reference hydrostatic pressure PHR at measuring point i can be determined from the following calculation: [Math. 1] Phr = Pmpx gx hFR where pMP is the average density of the circuit fluid pFC and the reservoir fluid pFR which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in circuit 2 to obtain the reference fluid mass M FR, g is the acceleration of gravity of the ambient medium, and hFR is the reference fluid height in circuit 2 for the reference fluid mass MFR at an average temperature Tmp of the circuit fluid TFC and the reservoir fluid TFR which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in the circuit to obtain the reference fluid mass MFR.

[0074] As a reminder, the density of the fluid in the pFC circuit is determined from the temperature of the fluid in the TFC circuit which is measured in step a3) via a relationship provided by the fluid manufacturer. The density of the fluid in the pFR reservoir is determined from the temperature of the fluid in the TFR reservoir which is measured in step cl) via a relationship provided by the fluid manufacturer.

[0075] More precisely, the weighted average density is determined from the following calculation: [Math. 4] pFC X cl + pFR X c2 where pFC is the density of the fluid in the circuit, P mp “M fr cl is the mass represented by the circuit fluid (mass determined in step a)), pFR is the density of the reservoir fluid and c2 is the mass represented by the reservoir fluid in circuit 2 to obtain the reference fluid mass MFR.

[0076] For example, if the reference fluid mass MFR is equal to 50 kg and the fluid mass of the MFC circuit determined in step a) is equal to 30 kg, then the coefficients cl and c2 are respectively equal to 30 and 20. In fact, 20 kg of fluid from the reservoir must be introduced to obtain the reference fluid mass MFR.

[0077] More precisely, in the same way, the weighted average temperature TMP is de- completed from the following calculation: [Math. 5] ry, _ Tpc X cl + TpS X c2 where TFC is the temperature of the circuit fluid 1mp “Mfr (temperature measured in step a3)), cl is the mass represented by the circuit fluid (mass determined in step a)), TFR is the temperature of the reservoir fluid (temperature measured in step cl)) and c2 is the mass represented by the reservoir fluid in circuit 2 to obtain the reference fluid mass MFR.

[0078] According to an alternative embodiment, step c) may comprise the sub-steps consisting of: cl) measure the temperature of the fluid in the TFR tank; c2) determine the volume of fluid from the reservoir to be introduced into the VFR1 circuit to obtain the reference fluid mass MFR, from the following calculation: [Math. 6] v _ MFR - MpCwhere Mfr is the mass of reference fluid, MFC is the mass of VFR1“ pZ" circuit fluid which is determined in step a) and pFR is the density of the reservoir fluid determined from the reservoir fluid temperature TFR which is measured in step cl) via a relationship provided by the fluid manufacturer; c3) filling circuit 2 with fluid from the reservoir with a volume VFR1 which is determined in sub-step c2), so that the mass of fluid in the MFC circuit is equal to the reference mass of fluid MFR.

[0079] For the variant explained above, advantageously, the filling system 6 comprises a volumetric counter in order to measure the volume of fluid from the reservoir to be introduced into the circuit VFR1.

[0080] The acceleration of gravity g is the acceleration of the free fall motion of heavy bodies. Its modulus varies from one place to another, it depends on the latitude and altitude of the place considered.

[0081] The method may comprise a step d) consisting of draining the circuit 2 until the mass of fluid in the MFC circuit is equal to the reference mass of fluid MFR, if the comparison carried out in step b) indicates that the mass of fluid in the MFC circuit is greater than the reference mass of fluid MFR.

[0082] The method may comprise a step e) consisting of comparing the static pressure of the fluid PSF at the measurement point i and a static control pressure PSc at the measurement point i, step e) being carried out following step c) or step d) after a predetermined period of time.

Claims

Claims

1. A method of filling a closed circuit (2) of an aircraft (3), the circuit (2) containing a fluid, the circuit (2) comprising at least one expansion tank (4), the method being carried out by means of an assembly (1) comprising at least the closed circuit (2) and a reservoir (5) independent of the circuit (2), the reservoir (5) containing fluid intended for filling the circuit (2), the method chronologically comprising the steps of: a) determining the fluid mass of the MFC circuit when the fluid is at rest; b) comparing the fluid mass of the MFC circuit determined in step a) with a predetermined reference fluid mass MFR for the circuit (2); c) filling the circuit (2) with fluid until the fluid mass of the MFC circuit is equal to the reference fluid mass MFR, if the comparison carried out in step b) indicates that the fluid mass of the MFC circuit is less than the reference fluid mass MFR.

2. Filling method according to claim 1, characterized in that step a) comprises the sub-steps consisting of: a1) measuring the static pressure of the fluid (PSF) at a measuring point (i) of the circuit (2); a2) measuring the ambient atmospheric pressure (Paa); a3) measuring the temperature of the circuit fluid (TFC); a4) determining the mass of fluid in the MFC circuit from the static pressure of the fluid (PSF) which is measured in step a1), the ambient atmospheric pressure (Paa) which is measured in step a2) and the temperature of the circuit fluid (TFC) which is measured in step a3).

3. Filling method according to claim 2, characterized in that step c) comprises the sub-steps consisting of: cl) measuring the temperature of the reservoir fluid (TFR); c2) determining a reference static pressure PSR at the measuring point (i) from the reference fluid mass MFR, the ambient atmospheric pressure (Paa) which is measured in step a2), the circuit fluid temperature (TFC) which is measured in step a3) and the reservoir fluid temperature (TFR) which is measured in step cl); c3) filling the circuit (2) with fluid until the static pressure of the fluid (PSF) at the measuring point (i) is equal to the static pressure of PSR reference at the measuring point (i) which is determined in step c2), so that the fluid mass of the MFC circuit is equal to the reference fluid mass MFR.

4. Filling method according to claim 3, characterized in that the reference static pressure PSR at the measuring point (i) is equal to the sum of the reference hydrostatic pressure PHR at the measuring point (i) and the ambient atmospheric pressure (Paa), the reference hydrostatic pressure PHR at the measuring point (i) being determined from the following formula: [Math.1] PhR= PmPX g X hpR where pMP is the average density of the circuit fluid pFC and the reservoir fluid pFR which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in circuit (2) to obtain the reference fluid mass MFR, g is the acceleration of gravity of the ambient medium, and hFR is the reference fluid height in circuit (2) for the reference fluid mass MFR at an average temperature TMP of the circuit fluid (TFC) and the reservoir fluid (TFR) which is weighted in proportion to the mass represented by the circuit fluid and the reservoir fluid in circuit (2) to obtain the reference fluid mass MFR.

5. Method according to one of the preceding claims, characterized in that it comprises a step d) consisting of draining the circuit (2) until the mass of fluid in the MFC circuit is equal to the mass of reference fluid MFR, if the comparison carried out in step b) indicates that the mass of fluid in the MFC circuit is greater than the mass of reference fluid MFR.

6. Method according to one of the preceding claims, characterized in that the closed circuit (2) is a cooling loop containing a heat transfer fluid.

7. Assembly (1) intended for implementing the method according to one of claims 1 to 6, the assembly (1) comprising: - a closed circuit (2) containing a fluid, the circuit (2) comprising at least one expansion tank (4); - a reservoir (5) independent of the circuit (2), the reservoir (5) containing fluid intended for filling the circuit (2); - a filling system (6) comprising at least one pump (7) configured to transfer fluid between the reservoir (5) and the circuit (2); - a control device (8) configured to control the filling system (6); - at least one first pipe (9) connected to both the filling system (6) and the tank (5); - at least one second pipe (10) connected to both the filling system (6) and the circuit (2); - a first pressure sensor (11) measuring the static pressure of the fluid (PSF) at a measurement point (i) of the circuit (2); - a second pressure sensor (12) measuring the ambient atmospheric pressure (Paa); - a first temperature sensor (13) measuring the temperature of the circuit fluid (TFC); - a second temperature sensor (14) measuring the temperature of the tank fluid (TFR); the tank (5), the filling system (6) and the first pipe (9) being part of airport equipment (15), and the closed circuit (2) being part of an aircraft (3).

8. Assembly (1) according to claim 7, characterized in that the closed circuit (2) comprises at least one heat exchanger configured to allow a transfer of thermal energy between the fluid of the closed circuit (2) and a second fluid of a second circuit.

9. Assembly (1) according to one of claims 7 to 8, characterized in that the closed circuit (2) is part of a propulsion group of the aircraft (3).

10. Assembly (1) according to claim 9, characterized in that the closed circuit (2) is located in a nacelle of the propulsion group.

11. Assembly (1) according to one of claims 7 to 10, characterized in that the closed circuit (2) is a cooling loop containing a heat transfer fluid.

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