Lubrication / cooling system for an aircraft, and hydraulic enclosure

Abstract

Disclosed is a lubrication / cooling system (100) for an aircraft, comprising: a first circuit (20), a second circuit (30), a third circuit (40) for circulating a lubricating and / or cooling fluid (13), a first pump (50) and a second pump (60) for circulating the lubricating and / or cooling fluid (13), a first tank (70) and a second tank (80), and a first heat exchanger (90), wherein the first tank (70) and the second tank (80) are fluidically connected. Also disclosed are a hydraulic enclosure for such a system (100) as well as a turbine engine and an aircraft comprising such a system and / or such an enclosure.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION

[0003] Aircraft lubrication / cooling system and hydraulic enclosure

[0004] TECHNICAL FIELD

[0005] The invention relates to lubrication / cooling devices for aircraft and more particularly to lubrication / cooling systems intended for the lubrication and cooling of turbomachines provided with an electric generator.

[0006] STATE OF THE PRIOR ART

[0007] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0008] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0009] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0010] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0011] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft.

[0012] In this respect, it should be remembered that conventional propulsion architectures of the turboshaft or turboprop type typically comprise two mechanical systems: the gas turbine and the power reducer. These two systems have technically different limitations concerning the operating temperatures of their respective lubrication circuits. The gas turbine alone contains only bearings and a chain of pinions driving the accessories necessary for its operation (typically: oil pump, fuel pump, FADEC alternator, starter generator, centrifugal oil separator): this assembly can operate with a first lubrication circuit whose oil temperatures are of the order of one hundred and thirty to one hundred and forty degrees Celsius at the inlet and up to one hundred and eighty degrees Celsius at the outlet.

[0013] The power reducer operates with a second lubrication circuit whose oil temperatures are around 110 to 120 degrees Celsius at the inlet and around 160 degrees Celsius at the outlet.

[0014] The oil pumped from the two lubrication circuits is directed to an oil / air heat exchanger to be cooled before being discharged into a tank where it will be pumped again to supply the lubrication circuits.

[0015] Although the two lubrication circuits have different supply and outlet temperatures, it is generally accepted to have only one oil-air exchanger, because the oversizing generated remains acceptable. This is typically the case on helicopter turboshaft engines.

[0016] For higher power machines and / or with a power reducer offering a higher reduction ratio, as is generally the case on turboprops, a second cooling system of the oil-fuel heat exchanger type can be added to ensure supercooling of part of the reducer lubrication circuit.

[0017] In the case of a hybrid engine, a third subsystem appears which is an electric machine composed of power electronics and an electric motor / generator. This third system requires a third lubrication circuit whose oil temperatures are in the order of sixty to ninety degrees Celsius at the inlet and which then requires a dedicated heat exchanger due to the inlet and outlet temperatures being much lower than those of the other two circuits. Such an exchanger represents an additional cost and excess weight which negatively impacts the aircraft's performance in terms of fuel consumption.

[0018] STATEMENT OF THE INVENTION

[0019] For this purpose, a lubrication / cooling system for an aircraft turbomachine is provided, comprising a first circuit for circulating a lubricating and / or cooling fluid intended to be connected to a first inlet and a first lubrication and / or cooling outlet of a gas turbine; a second circuit for circulating the lubricating and / or cooling fluid intended to be connected to a second inlet and a second lubrication and / or cooling outlet of a mechanical reducer; a third circuit for circulating the lubricating and / or cooling fluid intended to be connected to a third inlet and a third lubrication and / or cooling outlet of an electrical machine; a first pump for circulating the lubricating and / or cooling fluid comprising a first fluid suction port and a first fluid discharge port;a second circulation pump for the lubricating and / or cooling fluid comprising a second fluid suction port and a second fluid discharge port; a first reservoir, called the hot reservoir, for lubricating and / or cooling fluid comprising a first deaeration volume supplied by a fourth lubricating and / or cooling fluid inlet and a first supply volume connected to a fourth lubricating and / or cooling fluid outlet; a second reservoir, called the cold reservoir, for lubricating and / or cooling fluid comprising a second deaeration volume supplied by a fifth lubricating and / or cooling fluid inlet and a second supply volume connected to a fifth lubricating and / or cooling fluid outlet;a first fluid / air heat exchanger comprising a sixth inlet and a sixth outlet for lubricating and / or cooling fluid.;

[0020] According to the invention, the first circuit connects the first discharge port and the fourth inlet, the second circuit connects the first discharge port and the fourth inlet, the third circuit connects the sixth outlet and the fifth inlet, the fourth outlet is fluidically connected to the second suction port. The fifth outlet is fluidically connected to the first suction port, the sixth inlet is fluidically connected to the second discharge port. Finally, the first supply volume and the second supply volume are fluidically connected. This provides a device that allows the cooling of an electric machine to be integrated without requiring the addition of a dedicated heat exchanger or oversizing the exchanger in order to cool all of the circulating oil to the inlet temperature of the electric machine.

[0021] According to other particular, non-exclusive and optional embodiments of the invention:

[0022] - a third forcing pump fluidically connects the first supply volume and the second supply volume;

[0023] - the first tank and the second tank are combined in the same interior volume of a hydraulic enclosure and are separated by a partition extending into the interior volume;

[0024] - the partition and the hydraulic enclosure are arranged to limit thermal exchanges between the first and second tanks, for example using thermal insulation.

[0025] The invention also relates to a hydraulic enclosure for a lubrication system as described above, comprising an outer wall defining an inner volume which is crossed by a partition to delimit, together with the outer wall, a first reservoir, called the hot reservoir, and a second reservoir, called the cold reservoir; the first reservoir comprising a first deaeration volume supplied by a fourth fluid inlet as well as a first supply volume connected to a fourth fluid outlet, the second reservoir comprising a second deaeration volume supplied by a fifth fluid inlet as well as a second supply volume connected to a fifth fluid outlet, and in which the first supply volume is in fluid connection with the second supply volume.

[0026] Advantageously, the partition and the wall are arranged to limit thermal exchanges between the first and second tanks, for example using thermal insulation.

[0027] Advantageously, the hydraulic enclosure comprises a third reservoir which comprises a third deaeration volume supplied by a seventh fluid inlet as well as a third supply volume connected to a seventh fluid outlet. Preferably, the enclosure comprises a forcing pump fluidly connecting the first supply volume and the second supply volume.

[0028] The invention also relates to a lubrication / cooling method implementing a lubrication system as described above, comprising the following steps: transferring, using the second pump, the lubricating and / or cooling fluid from the first reservoir to the first heat exchanger; cooling and / or lubricating the electrical machine using the lubricating and / or cooling fluid taken from the outlet of the first heat exchanger; collecting the oil at the outlet of the electrical machine in the second reservoir; transferring, using the first pump, the lubricating and / or cooling fluid from the second reservoir to the gas turbine and the mechanical reducer to lubricate and / or cool the gas turbine and the mechanical reducer;transferring the lubricating and / or cooling fluid from the first lubricating and / or cooling outlet of the gas turbine and from the second lubricating and / or cooling outlet of the mechanical reducer to the first reservoir.;

[0029] The invention also relates to a turbomachine comprising a lubrication / cooling system as described above and / or a hydraulic enclosure as described above. The invention also relates to an aircraft comprising such a turbomachine.

[0030] Other characteristics and advantages of the invention will appear on reading the following description of a particular non-limiting embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Reference will be made to the attached figures, including:

[0032] [Fig.1] Figure 1 is a schematic sectional view of a turbomachine;

[0033] [Fig.2] Figure 2 is a schematic view of a lubrication / cooling circuit according to a first embodiment of the invention;

[0034] [Fig.3] Figure 3 is a schematic view of a lubrication / cooling circuit according to a second embodiment of the invention;

[0035] [Fig.4] Figure 4 is a schematic detail view of a third embodiment of the invention;

[0036] [Fig.5] Figure 5 is a schematic detail view of a fourth embodiment of the invention.

[0037] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0038] In a turbomachine, here a turboprop engine marked 1 in Figure 1 and which equips an aircraft not shown, the air is admitted into an inlet sleeve 2 after having passed through a propulsive propeller 3 comprising a series of rotating blades to then be compressed by compressor stages 4 before reaching a combustion chamber 5 into which fuel is injected and then burned. The pressurized gas flow generated in the combustion chamber 5 expands by passing through turbine stages 6, before being evacuated to the exhaust

[0039] The blades of the compressor stages 4 and the turbine stages 6 are rotationally fixed to a shaft 7 mounted to rotate relative to a casing 8 surrounding the compressor stages 4, the combustion chamber 5, the turbine stages 6, the casing 8 defining an exhaust outlet. The inlet sleeve 2, the compressor stages 4, the combustion chamber 5, the turbine stages 6 and the casing 8 define a gas turbine 9.

[0040] The shaft 7 of the gas turbine 9 is connected by a mechanical reducer 10 to the propeller 3. The reducer 10 is also provided with an output shaft 11 connected to an electrical machine comprising an electric motor / generator 12. The connection of the motor / generator 12 to the reducer 10 allows the motor / generator 12 to generate electricity when the turboprop is operating in 100% thermal mode, to drive the propeller 3 in 100% electric mode and to assist the turbine 9 in driving the propeller 3 in hybrid mode.

[0041] In this text, the terms "upstream" and "downstream" are used in reference to the position or orientation of an element according to the direction of flow of the fluid in the pipes.

[0042] The aircraft is equipped with a lubrication / cooling system 100 comprising a first circuit 20 for circulating a lubricating and / or cooling fluid—here oil 13—, a second circuit 30 for circulating oil 13 and a third circuit 40 for circulating oil 13.

[0043] The circuit 20 is connected to a first inlet 14 of the turbine 9 by a first supply pipe 21 and to a first outlet 15 of the turbine 9 by a first drainage pipe 22.

[0044] The circuit 30 is connected to a second inlet 16 of the reducer 10 by a second supply pipe 31 and to a second outlet 17 of the reducer 10 by a second drainage pipe 32.

[0045] The circuit 40 is connected to a third input 18 of the motor / generator 12 by a third supply line 41 and to a third output 19 of the motor / generator 12 by a third drainage line 42.

[0046] A first pump 50 for circulating the oil 13 comprises a first suction port 51 for oil 13 and a first discharge port 52 for oil 13.

[0047] A second oil 13 circulation pump 60 comprises a second oil 13 suction port 61 and a second oil 13 discharge port 62.

[0048] The system 100 also comprises a first reservoir 70, called the hot reservoir, comprising a first deaeration volume 71 supplied by a fourth inlet 72 of oil 13 as well as a first supply volume 73 connected to a fourth outlet 74 of oil 13. A second reservoir 80, called the cold reservoir, comprises a second deaeration volume 81 supplied by a fifth inlet 82 of oil 13 as well as a second supply volume 83 connected to a fifth outlet 84 of oil 13. Finally, a first fluid / air heat exchanger 90 comprises a sixth inlet 91 of oil 13 and a sixth outlet 92 of oil 13.

[0049] The circuit 20 connects the first discharge port 52 and the fourth inlet 72 via a connection from the upstream end 21.1 of the pipe 21 to the first discharge port 52 and a connection from the downstream end 22.1 of the pipe 22 to the fourth inlet 72.

[0050] The second circuit 30 connects the first discharge port 52 and the fourth inlet 72 via a connection from the upstream end 31.1 of the pipe 31 to the first discharge port 52 and a connection from the downstream end 32.1 of the pipe 32 to the fourth inlet 72.

[0051] The third circuit 40 connects the sixth outlet 92 and the fifth inlet 82 via a connection from the upstream end 41.1 of the pipe 41 to the sixth outlet 92 and a connection from the downstream end 42.1 of the pipe 42 to the fifth inlet 82.

[0052] The fourth outlet 74 is fluidically connected to the second suction port 61 by a fourth suction line 65.

[0053] The fifth outlet 84 is fluidically connected to the first suction port 51 by a fifth suction line 55.

[0054] The sixth inlet 91 is fluidically connected to the second discharge port 62 by a fourth discharge pipe 66.

[0055] The first supply volume 73 and the second supply volume 83 are fluidically connected by a sixth balancing line 93.

[0056] In operation, the pump 60 transfers the hot and deaerated oil 13 from the supply volume 73 of the hot reservoir 70 to the heat exchanger 90, the oil 13 thus cooled passes through the engine / generator 12 and is discharged into the deaeration volume 81 of the cold reservoir 80. The pump 50 then transfers the deaerated oil 13 from the supply volume 83 to the turbine 9 and the reducer 10, the oil 13 is then recovered at the outlet of the turbine 9 and the reducer 10 to be discharged into the deaeration volume 71 of the reservoir 70. Sending the hottest oil 13 of the system 100 to the heat exchanger 90 increases the efficiency thereof.

[0057] The line 93 is arranged to maintain identical oil levels in the volumes 83 and 73, to this end the tanks are arranged so that the ends 93.1 and 93.2 of the line 93 are located at identical levels to allow operation as “communicating vessels” of the two tanks 70 and 80.

[0058] Thus, during the operating phases of the turbomachine 1 in which the flow rates of the pumps 50 and 60 are different, the pipe 93 makes it possible to compensate for the difference in flow rates.

[0059] Elements identical or analogous to those previously described will bear a numerical reference identical to this one in the following description of a second, third, fourth and fifth embodiment of the invention.

[0060] As visible in Figure 3, and according to a second embodiment of the invention, a third forcing pump 95 is placed on the pipe 93 and thus fluidly connects the first supply volume 73 and the second supply volume 83. Such a configuration makes it possible to arrange the reservoirs 70 and 80 at freely chosen levels.

[0061] As visible in Figure 4, and according to a third embodiment of the invention, the first reservoir 70 and the second reservoir 80 are joined in the same interior volume 111 of a hydraulic enclosure 110 defined by a wall 120 and are separated by a partition 112 extending into the interior volume 111. In order to limit the heat exchanges between the reservoirs 70 and 80, the partition 112 is a double-skin partition comprising a first skin 113 and a second skin 114 separated by a thermal insulator 115—here rock wool. A vent—here a pipe 116 which passes through the partition 112—extends between the volumes 73 and 83 to ensure the fluid connection. The portions 121 and 122 of the wall 120 which define respectively with the partition 112 the tanks 70 and 80, are separated by thermal bridge breaker devices 117.As visible in Figure 5, and according to a fourth embodiment of the invention, the first supply volume 73 and the second supply volume 83 are fluidically connected by a fourth forcing pump 118.

[0062] According to a fifth embodiment not shown, the hydraulic enclosure 110 comprises an additional partition to define a third reservoir which comprises a third deaeration volume supplied by a seventh fluid inlet, a vent and a third supply volume connected to a seventh fluid outlet. This third reservoir is fluidically positioned at the outlet of the pumps 50 and 60 to supply the reservoirs 70 and 80 after having carried out a preliminary deaeration operation.

[0063] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims. In particular,

[0064] - although here the deaeration volume is not physically separated from the feed volume (the deaeration being carried out by natural settling), the invention also applies to other configurations of the deaeration and feed volumes such as for example a deaeration volume and a feed volume physically separated by a stilling wall or even by a deaerator;

[0065] - although here the exchanger is a fluid / air type exchanger, the invention also applies to other types of heat exchanger such as for example a fluid / fluid exchanger whose cold circuit would be supplied with fuel or coolant such as water.

Claims

CLAIMS 1. Lubrication / cooling system (100) for an aircraft turbomachine comprising a gas turbine (9), a mechanical reducer (10) and an electrical machine (12), the lubrication / cooling system (100) comprising: a first circuit (20) for circulating a lubricating and / or cooling fluid (13) intended to be connected to a first inlet (14) and to a first outlet (15) for lubricating and / or cooling a gas turbine (9); a second circuit (30) for circulating the lubricating and / or cooling fluid (13) intended to be connected to a second inlet (16) and to a second outlet (17) for lubricating and / or cooling a mechanical reducer (10); a third circuit (40) for circulating the lubricating and / or cooling fluid (13) intended to be connected to a third inlet (18) and to a third outlet (19) for lubricating and / or cooling an electrical machine (12);a first pump (50) for circulating the lubricating and / or cooling fluid (13) comprising a first suction port (51) for the lubricating and / or cooling fluid (13) and a first discharge port (52) for the lubricating and / or cooling fluid (13); a second pump (60) for circulating the lubricating and / or cooling fluid (13) comprising a second suction port (61) for the lubricating and / or cooling fluid (13) and a second discharge port (62) for the lubricating and / or cooling fluid (13); a first reservoir (70), called hot reservoir, of lubricating and / or cooling fluid (13) comprising a first deaeration volume (71) supplied by a fourth inlet (72) of lubricating and / or cooling fluid (13) as well as a first supply volume (73) connected to a fourth outlet (74) of lubricating and / or cooling fluid (13); a second reservoir (80), called cold reservoir, of lubricating and / or cooling fluid (13) comprising a second deaeration volume (81) supplied by a fifth inlet (82) of lubricating and / or cooling fluid (13) as well as a second supply volume (83) connected to a fifth outlet (84) of lubricating and / or cooling fluid (13);a first heat exchanger (90) comprising a sixth inlet (91) and a sixth outlet (92) for lubricating and / or cooling fluid (13), wherein: the first circuit (20) connects the first discharge port (52) and the fourth inlet (72); the second circuit (30) connects the first discharge port (52) and the fourth inlet (72); the third circuit (40) connects the sixth outlet (92) and the fifth inlet (18); the fourth outlet (74) is fluidly connected to the second suction port (61); the fifth outlet (84) is fluidly connected to the first suction port (51); the sixth inlet (91) is fluidly connected to the second discharge port (62), the first supply volume (73) and the second supply volume (83) are fluidly connected.; 2. A lubrication / cooling system (100) according to claim 1, comprising a third forcing pump (95) fluidly connecting the first supply volume (73) and the second supply volume (83).

3. Lubrication / cooling system (100) according to claim 1 or 2, wherein the first reservoir (70) and the second reservoir (80) are combined in the same interior volume (111) of a hydraulic enclosure (110) and are separated by a partition (112) extending into the interior volume (111).

4. Lubrication / cooling system (100) according to claim 3, wherein the partition (112) and the hydraulic enclosure (110) are arranged to limit heat exchanges between the first reservoir (70) and the second reservoir (80), for example using a thermal insulator (115).

5. Lubrication / cooling method implementing a lubrication system (100) according to any one of claims 1 to 4, comprising the following steps: transferring using the second pump (60) the lubricating and / or cooling fluid (13) from the first reservoir (70) to the first heat exchanger (90); cooling and / or lubricating the electric machine (12) using the lubricating and / or cooling fluid (13) taken from the outlet of the first heat exchanger (90); collecting the oil at the outlet of the electric machine (12) in the second reservoir (80); transferring by means of the first pump (50) the lubricating and / or cooling fluid (13) from the second reservoir (80) to the gas turbine (9) and the mechanical reducer (10) to lubricate and / or cool the gas turbine (9) and the mechanical reducer (10); transferring the lubricating and / or cooling fluid (13) from the first lubrication and / or cooling outlet of the gas turbine (9) and from the second lubrication and / or cooling outlet (17) of the mechanical reducer (10) to the first reservoir (70).

6. Turbomachine (1) comprising a lubrication / cooling system (100) according to any one of claims 1 to 4.

7. Aircraft comprising a turbomachine (1) according to claim 6.

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