Turbine engine for an aircraft and method for cooling same

Abstract

The invention relates to a turbine engine (2) for an aircraft, this turbine engine (2) comprising: - an annular flow path (V) for a gas flow (F3); - a motor (M); - at least one piece of equipment (E); - a first ACOC-type heat exchanger (210), which is capable of being swept by the gas flow (F3) and which comprises a first oil circuit (C1) connected to a cooling system (S1) of the motor; - a second ACOC-type heat exchanger (220), which is capable of being swept by the gas flow (F3) and which comprises a second oil circuit (C2) connected to a system (S2) for cooling the at least one piece of equipment (E); and - at least one third ACOC-type heat exchanger (230; 230') which is capable of being swept by the gas flow (F3) and which comprises at least one third oil circuit (C3, C3').

Description

[0001] DESCRIPTION

[0002] TITLE: TURBOMACHINE FOR AN AIRCRAFT AND ITS COOLING PROCESS

[0003] Technical field of the invention

[0004] The present invention relates to a turbomachine for an aircraft, and a method of cooling this turbomachine.

[0005] Technical background

[0006] The technical background includes in particular documents US-A1 - 2012 / 085528, W0-A1 -2023 / 099533 and FR-A1-3 099 797.

[0007] A turbomachine for an aircraft includes various components and / or equipment that need to be lubricated and / or cooled, such as rolling bearings, gears, etc. In addition, new generation turbomachines have on-board electrical machines for hybridization, these machines needing to be lubricated and cooled by oil. The heat released by these components is transported by the oil and removed to cold sources available on board.

[0008] Among the cold sources that exist on board, there are air and fuel. The oil can be cooled first by the fuel in a fuel / oil exchanger (generally known by the acronym FCOC, an acronym for the English expression "Fuel Cooled Oil Cooler"), which also has the function of heating the fuel before it enters the combustion chamber. FCOC exchangers are not sufficient to absorb all the heat dissipation because the fuel temperature is limited in view of safety constraints. Additional cooling can be provided by an air / oil exchanger (generally known by the acronym ACOC for "Air Cooled Oil Cooler").

[0009] The air constitutes a cold source for cooling the oil and can come for example from the secondary vein in the case of a double-flow turbomachine, or from the tertiary vein in the case of a triple-flow turbomachine as illustrated in figure 1 and described in document W0-A1 - 2023 / 099533.

[0010] ACOC exchangers are increasingly in demand in the future generation of engines due to the significant increase in heat dissipation, mainly due to:

[0011] - the engines of the future are larger, which increases the need for lubrication and cooling with oil;

[0012] - the presence of a speed reducer in new motor architectures, this reducer transmits very high mechanical power and needs to be lubricated and cooled by oil,

[0013] - adding electrical machines on board an engine for hybridization, these machines need to be lubricated and cooled by oil.

[0014] An engine may have several oil circuits, each with a defined function, for example a first circuit for cooling the oil dedicated to lubricating and cooling the engine, a second for lubricating and cooling the electrical machines, etc.

[0015] The oil temperature and flow rate must be controlled according to the corresponding circuit. For example, the oil used to lubricate and cool electrical machines has a different temperature range than that used for engine cooling. Therefore, the ACOC heat exchanger is preferably divided into several exchangers, each exchanger being dedicated to a given oil circuit. These different exchangers are installed in parallel in one of the turbomachine's veins, and occupy a part of this vein.

[0016] In Figure 2, the ACOC 1 heat exchanger can be used to cool the engine cooling oil. The ACOC 2 heat exchanger can be used to cool the oil of the electric machines for the hybridization of the turbomachine.

[0017] Each of the ACOCs 1 and 2 occupies a given angular sector of the vein. The vein V is delimited by coaxial annular walls 101, 102 which are connected to each other by structural arms 100 to ensure mechanical strength. The angular sectors denoted by “A” are sectors where the air circulates without any obstacle (no ACOC exchanger).

[0018] Each of the two exchangers must be sized for the most sizing case in order to dissipate the thermal power over all other flight phases.

[0019] The ACOC 1 heat exchanger is divided in Figure 3 into two parts:

[0020] - 1 a: part of the ACOC 1 exchanger used to ensure the cooling of the engine oil during all flight phases except the most dimensioning phases.

[0021] - 1 b: part of the ACOC 1 exchanger which is added to part 1 a in order to ensure additional cooling on the most dimensioning phases (case of aircraft on the ground on an extremely hot day as an example).

[0022] The ACOC 2 heat exchanger is divided in Figure 3 into two parts:

[0023] - 2a: part of the ACOC 2 exchanger used to cool the oil of the electrical machines during all flight phases except the most dimensioning phases, and

[0024] - 2b: part of the ACOC 2 exchanger which is added to part 1a in order to ensure additional cooling on the most dimensioning phases. The two ACOC exchangers (ACOC 1 and ACOC 2) provide different cooling functions. This results in different dimensioning phases for each of the two exchangers and leads to oversized exchangers on the other phases and flight conditions, which has a direct impact on the air-side pressure drop (aerothermal performance) and on the mass of the exchangers. This has the effect of increasing the specific consumption (SFC) of the turbomachine and consequently the fuel consumption (FB for Fuel Burn).

[0025] There is therefore a need to optimize the aerothermal performance of these exchangers.

[0026] The solution presented in EP-A1-2 472 067 proposes an ACOC exchanger buried in a compartment of the turbomachine. The heat exchanger is integrated in a cavity opening into a radially internal wall of the secondary stream. A portion of the secondary air flow, taken from the secondary stream, passes through the buried heat exchanger where the latter is reheated and is reinjected into the secondary stream. A controlled scoop, formed for example by a pivoting and / or translationally movable movable flap, is arranged at the inlet of the cavity so as to extend into the secondary stream and to produce an adjustable air flow towards the buried heat exchanger. The movable flap of the scoop can generate pressure losses in the secondary stream when it is open. The movable flap is controlled so as to close when the need for heat exchange in the buried heat exchanger becomes zero.

[0027] Patent WO-A1 -2022 / 123168A1 proposes a solution to optimize the aerothermal performance of the exchanger in a cavity and to reduce pressure losses thanks to a coupling between a movable flap and a movable member which allows adaptation to the different flight phases of the turbomachine and the aircraft. It relates to a heat exchange system for a turbomachine, comprising a cavity comprising an air inlet, a heat exchanger arranged in the cavity and comprising a first circuit in which a first fluid can circulate, a movable flap mounted at the air inlet and moving between two positions allowing or prohibiting, respectively, the circulation of an air flow in the cavity, a control device comprising a movable member intended to drive the movement of the movable flap.The control device is arranged in the supply circuit of the exchanger and is configured to authorize or prohibit the circulation of the first fluid towards the exchanger and to act simultaneously on one of the two positions of the movable flap.

[0028] The present invention provides a solution to the problems and needs of the prior art, which is simple, effective and economical.

[0029] Summary of the invention The invention relates to a turbomachine for an aircraft, this turbomachine comprising:

[0030] - an annular flow vein for a gas stream,

[0031] - an engine,

[0032] - at least one piece of equipment,

[0033] - a first heat exchanger of the ACOC type, which is capable of being swept by said gas flow and which comprises a first oil circuit connected to an engine cooling system,

[0034] - a second heat exchanger of the ACOC type, which is capable of being swept by said gas flow and which comprises a second oil circuit connected to a cooling system of said at least one piece of equipment, characterized in that it further comprises:

[0035] - at least one third heat exchanger of the ACOC type, which is capable of being swept by said gas flow and which comprises at least one third oil circuit, and

[0036] - connecting valves for the first, second and third circuits, which are capable of adopting three configurations:

[0037] - a first configuration in which said at least one third circuit is isolated from the first and second circuits,

[0038] - a second configuration in which the first circuit is connected in series with said at least one third circuit, the first and third circuits being isolated from the second circuit, and

[0039] - a third configuration in which the second circuit is connected in series with said at least one third circuit, the second and third circuits being isolated from the first circuit.

[0040] In this application, ACOC exchanger means an air / oil exchanger, ACOC being the acronym for “Air Cooled Oil Cooler”.

[0041] The invention proposes to size each of the first and second exchangers to ensure the cooling of the oil during all flight phases except for the dimensioning phases, and to add a third exchanger in the flow path which is common to the first and second exchangers and which will be used to ensure the additional cooling of the oil during the dimensioning phases. Given that the dimensioning phases for the first and second exchangers are not necessarily identical, the third exchanger can be used as a common exchanger to ensure the additional cooling during the dimensioning flight phases of each of the two oil circuits. Since the third exchanger is common to the other two exchangers, this makes it possible to reduce the section of the flow path occupied by the exchangers, and consequently to reduce the pressure losses linked to the exchangers.

[0042] Since the oil circuit of the third exchanger is likely to be connected to the circuit of the first exchanger and to the circuit of the second exchanger, it is preferable that the oils circulating in the circuits of the first and second exchangers are identical. Otherwise, the oil circulating in the third exchanger and coming for example from the first exchanger would risk being contaminated by oil from the second exchanger which would have previously circulated in the third exchanger, and vice versa.

[0043] The turbomachine according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another:

[0044] - the connecting valves are three-way valves and there are two of them, a first three-way valve comprising a first port connected to an outlet of the first circuit, a second port connected to an outlet of the second circuit and a third port connected to an inlet of said at least one third circuit, and a second three-way valve comprising a first port connected to the outlet of the first circuit, a second port connected to the outlet of the second circuit and a third port connected to an outlet of said at least one third circuit;

[0045] - the first circuit comprises a first outlet valve connected to an outlet of the first circuit, and the second circuit comprises a second outlet valve connected to an outlet of the second circuit; - the first outlet valve is located downstream of a connection point of the outlet of the first circuit to the first port of the first three-way valve, and upstream of a connection point of the outlet of the first circuit to the first port of the second three-way valve, and the second outlet valve is located downstream of a connection point of the outlet of the second circuit to the second port of the first three-way valve, and upstream of a connection point of the outlet of the second circuit to the second port of the second three-way valve;

[0046] - said at least one third heat exchanger is interposed circumferentially between the first and second heat exchangers in said vein;

[0047] - said at least one third heat exchanger is two or more in number, said second configuration being of two types:

[0048] - type I, in which the first circuit is connected in series with the third circuit of only one of the third exchangers, these first and third circuits being isolated from the second circuit, and

[0049] -- type II, in which the first circuit is connected in series with the third circuits of all the third exchangers, these first and third circuits being isolated from the second circuit; and said third configuration being of two types:

[0050] - type I, in which the second circuit is connected in series with the third circuit of only one of the third exchangers, these second and third circuits being isolated from the first circuit;

[0051] -- type II, in which the second circuit is connected in series with the third circuit of all third exchangers, these second and third circuits being isolated from the first circuit;

[0052] - said vein is a secondary flow vein for a secondary gas flow, the turbomachine further comprising a primary flow vein for a primary gas flow inside said engine;

[0053] - said vein is a tertiary flow vein for a tertiary gas flow, the turbomachine further comprising two annular veins, respectively primary and secondary, for the flow of primary and secondary gas flows;

[0054] - the tertiary vein is intercalated radially between the primary and secondary veins;

[0055] - said at least one third heat exchanger has a cooling capacity lower than that of the first heat exchanger, and lower than that of the second heat exchanger;

[0056] - said at least one piece of equipment comprises electrical machines;

[0057] -- the said engine is a gas generator.

[0058] The invention further relates to a cooling method in a turbomachine as described above, in which it comprises three steps corresponding to the three aforementioned configurations:

[0059] - a first step corresponding to the first configuration, in which the engine cooling system is supplied by oil leaving the first exchanger, and the cooling system of said at least one piece of equipment is supplied by oil leaving the second exchanger,

[0060] - a second step corresponding to the second configuration, in which the engine cooling system is supplied by oil leaving the first exchanger and passing through said at least one third exchanger, and the cooling system of said at least one piece of equipment is supplied by oil leaving the second exchanger, and

[0061] - a third step corresponding to the third configuration, in which the engine cooling system is supplied by oil leaving the first exchanger, and the cooling system of said at least one piece of equipment is supplied by oil leaving the second exchanger and passing through said at least one third exchanger.

[0062] The method according to the invention may comprise one or more of the following characteristics or steps, taken in isolation from one another, or in combination with one another: - the second step occurs when the aircraft is on the ground and the ambient outside temperature is above a predetermined threshold,

[0063] - the third stage occurs when the aircraft is in the descent phase and the ambient outside temperature is above a predetermined threshold, and

[0064] - the first step occurs by default in other cases;

[0065] - the first heat exchanger is supplied with oil at a maximum temperature of 160°C, and the second heat exchanger is supplied with oil at a maximum temperature of 90°C.

[0066] Brief description of the figures

[0067] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0068] [Fig.1] Figure 1 is a schematic axial sectional view of a turbomachine for an aircraft;

[0069] [Fig.2] Figure 2 is a very schematic cross-sectional view of a flow vein of a gas stream, in which heat exchangers are located,

[0070] [Fig.3] Figure 3 is a view similar to that of Figure 2 and shows a breakdown of the heat exchangers,

[0071] [Fig. 4] Figure 4 is a schematic cross-sectional view of a flow vein of a gas stream, in which three heat exchangers are located, and illustrates an embodiment of the invention,

[0072] [Fig.5] Figure 5 is a very schematic view of the three heat exchangers of Figure 4 and shows a first configuration of exchanger connection valves,

[0073] [Fig.6] Figure 6 is a view similar to that of Figure 4 and shows the first configuration of the valves,

[0074] [Fig.7] Figure 7 is a view similar to that of Figure 5 and shows a second configuration of the exchanger connecting valves, [Fig.8] Figure 8 is a view similar to that of Figure 6 and shows the second configuration of the valves,

[0075] [Fig.9] Figure 9 is a view similar to that of Figure 5 and shows a third configuration of the exchanger connecting valves,

[0076] [Fig.10] Figure 10 is a view similar to that of Figure 6 and shows the third configuration of the valves,

[0077] [Fig.11] Figure 11 is a view similar to that of Figure 4 and illustrates an alternative embodiment of the invention,

[0078] [Fig.12] Figure 12 is a very schematic view of the heat exchangers of Figure 11 and shows a first configuration of the exchanger connection valves,

[0079] [Fig.13] Figure 13 is a very schematic view of the heat exchangers of Figure 11 and shows one type of each of the second and third configurations of the exchanger connecting valves,

[0080] [Fig.14] Figure 14 is a very schematic view of the heat exchangers of Figure 11 and shows another type of the second configuration of the exchanger connecting valves, and

[0081] [Fig.15] Figure 15 is a very schematic view of the heat exchangers of Figure 11 and shows another type of the third configuration of the exchanger connecting valves.

[0082] Detailed description of the invention

[0083] Figure 1 shows a turbomachine 2 for an aircraft. This turbomachine 2 illustrates the prior art as described in document WO-A1 - 2023 / 099533, but can be used to describe an installation environment of the invention.

[0084] The turbomachine 2 moves in an air flow F whose movement relative to the turbomachine 2 is generated by the rotation of the propeller 4 and the advancement of the aircraft on which the turbomachine 2 is mounted.

[0085] The air flow F is separated by a first separation nozzle 10 into a radially internal air flow F' and a radially external air flow F2, called secondary flow F2. The propeller 4 can be arranged upstream of the first separation nozzle 10 or downstream.

[0086] The radially internal air flow F' passes through a moving wheel 12 which directs the latter towards a second separation nozzle 14 capable of separating the radially internal air flow F' into a primary flow F1 and a tertiary flow F3, the latter being distinct from the secondary flow F2.

[0087] The first separation nozzle 10 comprises an inner wall forming a first outer guide wall 11 of the radially inner air flow F', said first outer guide wall 11 forming a convex profile seen from said radially inner air flow F'.

[0088] The second separation nozzle 14 comprises an external wall forming a second external guide wall 13 for the radially internal air flow F' having passed through the moving wheel 12, said second external guide wall 13 forming a convex profile seen from the tertiary flow F3.

[0089] The tertiary flow F3 enters a tertiary flow vein 16 radially external to said primary flow F1. The tertiary flow F3 passes through a heat exchanger 18 arranged in the tertiary flow vein 16.

[0090] The turbomachine 2 is illustrated symmetrically with respect to the longitudinal axis 8. Indeed, the tertiary flow vein 16 is annular and circumferentially continuous over 360° around the longitudinal axis 8. For this purpose, the tertiary flow F3 is a flow which passes annularly through the tertiary flow vein 16.

[0091] In this configuration, the tertiary flow F3 extends essentially in the axial direction and in a position radially between the primary flow F1 and the secondary flow F2.

[0092] The tertiary flow F3 extends in the tertiary flow vein 16 from the radially internal air flow F' downstream of the moving wheel 12 and to the secondary flow F2 after passing through the heat exchanger 18.

[0093] The turbomachine 2 further comprises a stator (not shown) arranged upstream of the heat exchanger 18 at the level of the tertiary flow vein 16. Advantageously, the stator makes it possible to straighten the tertiary flow F3 before the latter passes through the heat exchanger 18 in order to minimize the aerodynamic disturbances of the tertiary flow F3 which can be caused by the moving wheel 12, this makes it possible to optimize the heat exchange between the air and the oil.

[0094] The stator corresponds to a row of stator vanes arranged in the tertiary flow stream downstream of the separation nozzle 14. Alternatively, the stator may be arranged upstream of the separation nozzle 14 and downstream of the moving wheel 12.

[0095] The heat exchanger 18 extends radially and axially in an upstream section 20 of the tertiary flow vein 16, having a longitudinal section diverging in the direction of flow of the tertiary flow F3.

[0096] The heat exchanger 18 is arranged axially between the low pressure compressor 17 and the high pressure compressor 15 in the example shown.

[0097] A discharge channel of the “VBV” type 19 (Variable Bleed Valve) having an outlet passing through an internal wall of the tertiary flow vein 16 and arranged axially downstream of the heat exchanger 18, the “VBV” channel makes it possible to ensure a discharge function by returning a portion of the primary flow F1 to the tertiary flow F3, this makes it possible to evacuate, for example, any ice particles from the primary flow F1 to avoid clogging of the high-pressure compressor 15, in particular when the flow rate of the primary flow F1 becomes too low.

[0098] Advantageously, the arrangement of the outlet of the “VBV” channel 19 downstream of the heat exchanger 18 makes it possible to protect the latter from any possible risk of blockage.

[0099] The heat exchanger 18 can extend continuously over 360° in the upstream section 20 of the vein 16 around the longitudinal axis 8 of the turbomachine 2. Preferably, the heat exchanger 18 extends discontinuously over 360° around the longitudinal axis 8 by being subdivided into several angular segments and each can provide a heat exchange function between the air and the oil which can be different from one segment to another.

[0100] The heat exchanger 18 is of the “ACOC” type, an acronym for the English expression “Air Cooled Oil Cooler”, comprising oil passages which extend in the tertiary flow stream, said oil passages extending particularly in a radial and axial direction between an upper wall and a lower wall of said heat exchanger 18. Advantageously, the “ACOC” heat exchanger 18 allows heat exchange between the air and the oil, preferably cooling of the oil by the air. Indeed, the temperature of the oil can reach an operating temperature of up to 180°C and a flow rate reaching 30,000 l / h. In this regard, the exchanger 18 can ensure the cooling of the oil used in several components of the aircraft, in particular, an engine, a gearbox, an engine generator and any electronic component requiring cooling.

[0101] A single heat exchanger 18 can combine the cooling of several functions or oil circuits of the turbomachine, and this depending on different parameters linked to the need for cooling the oil, i.e. inlet temperatures, flow rates, required outlet temperature or air conditions, the different circuits can be put in thermal contact or insulated. The exchanger 18 and in particular its oil passages can withstand a low oil temperature of up to -54°C.

[0102] Figures 2 and 3 have been described in the above.

[0103] Figure 4 illustrates an embodiment of the invention and shows very schematically an annular flow vein V of a gas flow in a turbomachine. This turbomachine can be of the triple flow type as described above and illustrated in Figure 1. It is then understood that the vein V is a tertiary flow vein 16 of a tertiary flow F3.

[0104] Alternatively, the turbomachine could be of the double-flow type, and vein V could be a secondary flow vein of a secondary flow.

[0105] It is therefore understood that the type of turbomachine is not limiting within the scope of the present invention.

[0106] The turbomachine according to the invention comprises, in addition to the vein V, an engine M and at least one piece of equipment E.

[0107] The engine M is preferably the gas generator of the turbomachine and therefore comprises at least one compressor, an annular combustion chamber, and at least one turbine.

[0108] Said at least one piece of equipment E is, for example, an electrical machine or several electrical machines.

[0109] The vein V has an annular shape around an axis 8 which is generally the longitudinal axis of the turbomachine. The vein comprises two coaxial annular walls, respectively internal 101 and external 102, which are connected to each other by radial arms 100, four in number in the example shown.

[0110] The arms 100 divide the vein V into angular sectors, some of which are empty to allow the gas flow to pass without obstacle, and others are occupied by exchangers 210, 220, 230.

[0111] The turbomachine is equipped with three ACOC type exchangers 210, 220, 230.

[0112] The first exchanger 210 is capable of being swept by the flow of gas flowing in the vein V and comprises a first oil circuit C1 connected to a system S1 for cooling the engine M.

[0113] The second exchanger 220 is capable of being swept by the gas flow and comprises a second oil circuit C2 connected to a system S2 for cooling the equipment(s) E. The third exchanger 230 is also capable of being swept by the gas flow and comprises a third oil circuit C3.

[0114] In the example shown, each exchanger is located in the vein V and occupies a part of the passage section of this vein V. For example, the first exchanger 210 can occupy the entire radial extent or dimension of the vein, or only a part of this radial extent, and extend in the circumferential direction over a part, and for example 2 / 3, of an angular sector of the vein V between two arms 100. The second exchanger 220 can occupy the entire radial extent or dimension of the vein, or only a part of this radial extent, and extend in the circumferential direction over a part, and for example 2 / 3, of another angular sector of the vein V between two arms 100. The third exchanger 230 can occupy the entire radial extent or dimension of the vein, or only a part of this radial extent, and extend in the circumferential direction between the two exchangers 210, 220.The third exchanger 230 can, for example, occupy the remainder of the circumferential space of the angular sector in which the second exchanger 220 is located.

[0115] Preferably, the third exchanger 230 has a cooling capacity lower than that of the first heat exchanger 210, and lower than that of the second heat exchanger 220. In practice, this may mean that the third exchanger 230 occupies a portion of the passage section of the gas flow in the vein V, which is lower than that of the first heat exchanger 210, and lower than that of the second heat exchanger 220.

[0116] Figures 5 and following show the fluid connections between the exchangers 210, 220, 230 and in particular between the circuits C1, C2, C3 of these exchangers.

[0117] The turbomachine according to the invention comprises valves 310, 320 for connecting the first, second and third circuits C1, C2, C3, which are capable of adopting three distinct configurations illustrated in Figures 5 and following. According to a first configuration illustrated in Figures 5 and 6, the third circuit C3 is isolated from the first and second circuits C1, C2.

[0118] According to a second configuration illustrated in figures 7 and 8, the first and third circuits C1, C3 are connected in series and are isolated from the second circuit C2.

[0119] According to a third configuration illustrated in figures 9 and 10, the second and third circuits C2, C3 are connected in series and are isolated from the first circuit C1.

[0120] Advantageously, the connecting valves 310, 320 are three-way valves.

[0121] These valves 310, 320 can be two in number:

[0122] - a first three-way valve 310 comprises a first port 310a connected to an output C1s of the first circuit C1, a second port 310b connected to an output C2s of the second circuit C2 and a third port 310c connected to an input C3e of the third circuit C3, and

[0123] - a second three-way valve 320 comprises a first port 320a connected to the output C1s of the first circuit, a second port 320b connected to the output C2s of the second circuit C2 and a third port 320c connected to an output C3s of the third circuit C3.

[0124] The first circuit C1 may comprise a first outlet valve 410 connected to the outlet C1 s of the first circuit C1. The first circuit C1 could also comprise a first inlet valve (not shown) connected to the inlet C1 e of the first circuit C1.

[0125] The second circuit C2 may comprise a second outlet valve 420 connected to the outlet C2s of the second circuit C2. The second circuit C2 could also comprise a second inlet valve (not shown) connected to the inlet C2e of the second circuit C2.

[0126] In the example shown, the first outlet valve 410 is located downstream of a connection point P1 of the outlet C1s of the first circuit C1 to the first port 310a of the first three-way valve 310, and upstream of a connection point P2 of the outlet C1s of the first circuit C1 to the first port 320a of the second three-way valve 320. In the same way, the second outlet valve 420 is located downstream of a connection point P3 of the outlet C2s of the second circuit C2 to the second port 310b of the first three-way valve 310, and upstream of a connection point P4 of the outlet C2s of the second circuit C2 to the second port 320b of the second three-way valve 320.

[0127] The present invention also relates to a cooling method in the turbomachine according to the invention, this method comprising three steps corresponding to the three aforementioned configurations.

[0128] According to a first step corresponding to the first configuration, the cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210, and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220. This step and this configuration are illustrated in figures 5 and 6 in which the arrows in continuous lines are seen which show the circulation of the oil in each of the exchangers 210, 220. The exchanger 230 is isolated and is not used in this step / configuration.

[0129] This first step / configuration can be adopted by default in most phases of turbomachine operation and aircraft flight.

[0130] According to a second step corresponding to the second configuration, the cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210 and passing through the third exchanger 230, and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220. This step and this configuration are illustrated in Figures 7 and 8 in which the arrows in solid lines are seen which show the circulation of the oil in each of the exchangers 210, 220, 230. The outlet C1s of the first exchanger 210 is connected to the inlet C3e of the third exchanger 230 so the oil leaving the first exchanger 210 circulates in the third exchanger 230 in order to be further cooled. This second step / configuration can be adopted when the aircraft is on the ground and the ambient outside temperature is above a predetermined threshold.

[0131] According to a third step corresponding to the third configuration, the cooling system S3 of the engine M is supplied by oil leaving the first exchanger 210, and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220 and passing through the third exchanger 230. This step and this configuration are illustrated in Figures 9 and 10 in which the arrows in solid lines are seen which show the circulation of the oil in each of the exchangers 210, 220, 230. The outlet C2s of the second exchanger 220 is connected to the inlet C3e of the third exchanger 230 so the oil leaving the second exchanger 220 circulates in the third exchanger 230 in order to be further cooled.

[0132] This third step / configuration can be adopted when the aircraft is in the descent phase and the ambient outside temperature is above a predetermined threshold.

[0133] Figures 11 to 15 illustrate an alternative embodiment in which there are at least two or more third exchangers 230, 230'.

[0134] The first and second exchangers 210, 220 are similar to those described above.

[0135] The two third exchangers 230, 230' are both capable of being swept by the gas flow and each comprise a third oil circuit C3, C3'.

[0136] The third exchanger 230 may occupy the entire radial extent or dimension of the vein, or only part of this radial extent, and extend in the circumferential direction over one half of the remainder of the circumferential space of the angular sector in which the second exchanger 220 is located. The third exchanger 230' may occupy the entire radial extent or dimension of the vein, or only part of this radial extent, and extend in the circumferential direction over the other half of the remainder of the circumferential space of the angular sector in which the second exchanger 220 is located.

[0137] The third exchangers 230, 230' may have identical or different cooling capacities from each other. In practice, this may mean that the third exchangers 230 occupy portions of the gas flow passage section in the vein V, which are identical or different.

[0138] Figures 12 and following show the fluid connections between the exchangers 210, 220, 230, 230' and in particular between the circuits C1, C2, C3, C3' of these exchangers.

[0139] The turbomachine according to the invention comprises valves 310, 320, 330, 340 for connecting the first, second and third circuits C1, C2, C3, C3'.

[0140] Advantageously, the connecting valves 310, 320, 330, 340 are three-way valves.

[0141] These valves 310, 320, 330, 340 can be four in number:

[0142] - a first three-way valve 310 comprises a first port 310a connected to an output C1s of the first circuit C1, a second port 310b connected to an output C3s of the third circuit C3', and a third port 310c connected to an input C3e of the third circuit C3,

[0143] - a second three-way valve 320 comprises a first port 320a connected to the output C1s of the first circuit, a second port 320b connected to the output C2s of the second circuit C2, and a third port 320c connected to an output C3s of the third circuit C3,

[0144] - a third three-way valve 330 comprises a first port 33a connected to the output C3s of the third circuit C3, a second port 330b connected to the output C2s of the second circuit C2, and a third port 330c connected to an inlet C3'e of the third circuit C3', and

[0145] - a fourth three-way valve 340 comprises a first port 340a connected to the output C1s of the first circuit, a second port 340b connected to the output C2s of the second circuit C2, and a third port 340c connected to an output C3's of the third circuit C3'.

[0146] The first circuit C1 may comprise a first outlet valve 410 connected to the outlet C1 s of the first circuit C1. The first circuit C1 could also comprise a first inlet valve (not shown) connected to the inlet C1 e of the first circuit C1.

[0147] The second circuit C2 may comprise a second outlet valve 420 connected to the outlet C2s of the second circuit C2. The second circuit C2 could also comprise a second inlet valve (not shown) connected to the inlet C2e of the second circuit C2.

[0148] In the example shown, the first outlet valve 410 is located downstream of a connection point P5 of the outlet C1s of the first circuit C1 to the first port 310a of the first three-way valve 310, and upstream of connection points P6, P7 of the outlet C1s of the first circuit C1 to the first port 320a of the second three-way valve 320, and to the first port 340a of the fourth three-way valve 340. In the same way, the second outlet valve 420 is located downstream of a connection point P8 of the outlet C2s of the second circuit C2 to the second port 330b of the third three-way valve 310, and upstream of connection point P9, P10 of the outlet C2s of the second circuit C2 to the second port 320b of the second three-way valve 320, and to the second port 340b of the fourth three-way valve 340.

[0149] The valves 310, 320, 330, 340 are capable of adopting three distinct configurations illustrated in figures 12 and following, as well as two types for each of the second and third configurations.

[0150] According to a first configuration illustrated in figure 12, the third circuits C3, C3' are isolated from the first and second circuits C1, C2.

[0151] The cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210, and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220. This first step / configuration can be adopted by default in most of the operating phases of the turbomachine and flight of the aircraft.

[0152] According to a second configuration illustrated in figure 13, the first and third circuits C1, C3 are connected in series, on the one hand, and the second and third circuits C2, C3' are connected in series on the other hand.

[0153] This figure 13 illustrates a first type of the second configuration with regard to the first exchanger 210 and also a first type of the third configuration with regard to the second exchanger 220.

[0154] The cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210 and then passing through the third exchanger 230, and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220 and then passing through the third exchanger 230'.

[0155] The output C1s of the first exchanger 210 is connected to the inlet C3e of the third exchanger 230, so the oil leaving the first exchanger 210 circulates in the third exchanger 230 to be further cooled. The output C2s of the second exchanger 220 is connected to the inlet C3'e of the third exchanger 230', so the oil leaving the second exchanger 220 circulates in the third exchanger 230' to be further cooled.

[0156] This first type of each of the second and third configurations may be adopted when the aircraft is on the ground and the ambient outside temperature is above a predetermined threshold, or when the aircraft is in the descent phase and the ambient outside temperature is above a predetermined threshold.

[0157] According to a second type of the second configuration illustrated in Figure 14, the first and third circuits C1, C3, C3' are all connected in series and are isolated from the second circuit C2.

[0158] The cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210 and then passing through the third exchangers 230, 230', and the cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220. The outlet C1s of the first exchanger 210 is connected to the inlet C3e of the third exchanger 230, and the outlet C3s of the third exchanger 230 is connected to the inlet C3'e of the other third exchanger 230', so the oil leaving the first exchanger 210 circulates in the third exchangers 230, 230' in order to be further cooled.

[0159] This second type of the second configuration can be adopted when the aircraft is on the ground and the ambient outside temperature is above a predetermined threshold.

[0160] According to a second type of the third configuration illustrated in Figure 15, the second and third circuits C2, C3, C3' are all connected in series and are isolated from the first circuit C1.

[0161] The cooling system S2 of the equipment(s) E is supplied by oil leaving the second exchanger 220 and then passing through the third exchangers 230, 230', and the cooling system S1 of the engine M is supplied by oil leaving the first exchanger 210.

[0162] The outlet C2s of the second exchanger 220 is connected to the inlet C3”e of the third exchanger 230', and the outlet C3s of the third exchanger 230' is connected to the inlet C3e of the other third exchanger 230, so the oil leaving the first exchanger 210 circulates in the third exchangers 230', 230 in order to be further cooled.

[0163] This second type of the third configuration can be adopted when the aircraft is in the descent phase and the ambient outside temperature is above a predetermined threshold.

[0164] The present invention also relates to a cooling method in the turbomachine according to the invention, this method comprising three steps corresponding to the three aforementioned configurations and to the types mentioned above for each of the second and third configurations.

[0165] The first exchanger 210 can be supplied with oil at a maximum temperature of 160°C. The second exchanger 220 can be supplied with oil at a maximum temperature of 90°C.

Claims

CLAIMS 1. Turbomachine (2) for an aircraft, this turbomachine (2) comprising: - an annular vein (V) for the flow of a gas flow (F3), - an engine (M), - at least one piece of equipment (E), - a first heat exchanger (210) of the ACOC type, which is capable of being swept by said gas flow (F3) and which comprises a first oil circuit (C1) connected to an engine cooling system (S1), - a second heat exchanger (220) of the ACOC type, which is capable of being swept by said gas flow (F3) and which comprises a second oil circuit (C2) connected to a system (S2) for cooling said at least one item of equipment (E), characterized in that it further comprises: - at least one third heat exchanger (230, 230') of the ACOC type, which is capable of being swept by said gas flow (F3) and which comprises at least one third oil circuit (C3, C3'), and - valves (310, 320, 330, 340) for connecting the first, second and third circuits (C3, C3'), which are capable of adopting three configurations: - a first configuration in which said at least one third circuit (C3, C3') is isolated from the first and second circuits (C1, C2), - a second configuration in which the first circuit (C1) is connected in series with said at least one third circuit (C3, C3'), the first and third circuits (C1, C3, C3') being isolated from the second circuit (C2), and - a third configuration in which the second circuit (C2) is connected in series with said at least one third circuit (C3, C3'), the second and third circuits (C2, C3, C3') being isolated from the first circuit (C1).

2. Turbomachine (2) according to claim 1, in which the connecting valves (310, 320) are three-way valves and there are two of them, a first three-way valve (310) comprising a first port (310a) connected to an output (C1 s) of the first circuit (C1 ), a second port (31 Ob) connected to an output (C2s) of the second circuit (C2) and a third port (310c) connected to an input (C3e) of said at least one third circuit (C3), and a second three-way valve (320) comprising a first port (320a) connected to the output (C1 s) of the first circuit (C1 ), a second port (320b) connected to the output (C2s) of the second circuit (C2) and a third port (320c) connected to an output (C3s) of said at least one third circuit (C3).

3. Turbomachine (2) according to claim 1 or 2, in which the first circuit (C1) comprises a first outlet valve (410) connected to an outlet (C1s) of the first circuit (C1), and the second circuit (C2) comprises a second outlet valve (420) connected to an outlet (C2s) of the second circuit (C2).

4. Turbomachine (2) according to all of claims 2 and 3, in which the first outlet valve (410) is located downstream of a point (P1) of connection of the outlet (C1s) of the first circuit (C1) to the first port (310a) of the first three-way valve (310), and upstream of a point (P2) of connection of the outlet (C1s) of the first circuit (C1) to the first port (320a) of the second three-way valve (320), and the second outlet valve (420) is located downstream of a point (P3) of connection of the outlet (C2s) of the second circuit (C2) to the second port (310b) of the first three-way valve (310), and upstream of a point (P4) of connection of the outlet (C2s) of the second circuit (C2) to the second port (320b) of the second three-way valve. (320).

5. Turbomachine (2) according to one of the preceding claims, in which said at least one third heat exchanger (230, 230') is interposed circumferentially between the first and second heat exchangers (210, 220) in said vein (V).

6. Turbomachine (2) according to one of the preceding claims, in which said at least one third heat exchanger (230, 230') is two or more in number, said second configuration being of two types: - type I, in which the first circuit (C1) is connected in series with the third circuit (C3) of only one of the third exchangers (330), these first and third circuits (C1, C3, C3') being isolated from the second circuit (C2), and -- type II, in which the first circuit (C1) is connected in series with the third circuits (C3, C3') of all the third exchangers (230, 230'), these first and third circuits (C1, C3, C3') being isolated from the second circuit (C2), and said third configuration being of two types: - type I, in which the second circuit (C2) is connected in series with the third circuit (C3') of only one of the third exchangers (230'), these second and third circuits (C2, C3, C3') being isolated from the first circuit (C1). -- type II, in which the second circuit (C2) is connected in series with the third circuits (C3, C3') of all the third exchangers (230, 230'), these second and third circuits (C2, C3, C3') being isolated from the first circuit (C1).

7. Turbomachine (2) according to one of the preceding claims, in which said vein (V) is a secondary flow vein of a secondary gas flow, the turbomachine (2) further comprising a primary flow vein of a primary gas flow (F1) inside said engine.

8. Turbomachine (2) according to one of claims 1 to 6, in which said vein (V) is a tertiary flow vein of a tertiary gas flow (F3), the turbomachine further comprising two annular veins, respectively primary and secondary flow veins of primary and secondary gas flow (F1, F2).

9. Turbomachine (2) according to the preceding claim, in which the tertiary vein is interposed radially between the primary and secondary veins.

10. Turbomachine (2) according to one of the preceding claims, in which said at least one third heat exchanger (230, 230') has a cooling capacity lower than that of the first heat exchanger (210), and lower than that of the second heat exchanger (220).

11. Turbomachine (2) according to one of the preceding claims, in which said at least one piece of equipment (E) comprises electrical machines.

12. Cooling method in a turbomachine (2) according to one of the preceding claims, in which it comprises three steps corresponding to the three aforementioned configurations: - a first step corresponding to the first configuration, in which the system (S1) for cooling the engine (M) is supplied by oil leaving the first exchanger (210), and the system (S2) for cooling said at least one piece of equipment (E) is supplied by oil leaving the second exchanger (220), - a second step corresponding to the second configuration, in which the system (S1) for cooling the engine (M) is supplied by oil leaving the first exchanger (310) and passing through said at least one third exchanger (230, 230'), and the system (S2) for cooling said at least one piece of equipment (E) is supplied by oil leaving the second exchanger (220), and - a third step corresponding to the third configuration, in which the system (S1) for cooling the engine (M) is supplied by oil leaving the first exchanger (210), and the system (S2) for cooling said at least one piece of equipment (E) is supplied by oil leaving the second exchanger (220) and passing through said at least one third exchanger (230, 230').

13. The method of claim 12, wherein: - the second stage occurs when the aircraft is on the ground and the ambient outside temperature is above a predetermined threshold, - the third stage occurs when the aircraft is in the descent phase and the ambient outside temperature is above a predetermined threshold, and - the first step occurs by default in other cases.

14. Method according to claim 12 or 13, wherein the first heat exchanger (210) is supplied with oil at a maximum temperature of 160°C, and the second heat exchanger (220) is supplied with oil at a maximum temperature of 90°C.

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