HEAT EXCHANGER MOUNTED IN A CAVITY OF A TURBINE ENGINE

Description

Field of invention

[0001] The present invention relates to the general field of aeronautics. It relates in particular to a heat exchange system comprising a heat exchanger which is buried in a cavity of a turbomachine. The invention also relates to the turbomachine and the method for implementing the heat exchange system. Technical background

[0002] A turbomachine, particularly an aircraft turbomachine, comprises various components and / or equipment that must be lubricated and / or cooled, such as rolling bearings and gears. The heat released by these components, which can be very significant depending on the power of the component and / or equipment, is transported by a fluid and evacuated to cold sources available in the aircraft.

[0003] It is known to equip the turbomachine with one or more heat exchangers to carry out the heat exchange between the fluid (typically oil) and the cold source (air, fuel, etc.). There are different types of heat exchangers, for example fuel / oil heat exchangers generally known by the English acronym FCOC for "Fuel Cooled Oil Cooler" and air / oil heat exchangers known by the English acronym ACOC for "Air-Cooled Oil Cooler". The latter are generally installed in addition to the FCOC exchangers which are insufficient to meet the growing needs in terms of fluid cooling in the turbomachine. Examples of heat exchangers are described in the patent documents EP-A2-2492199, US-A1-2019 / 390602, and EP-A1-3453845.

[0004] The ACOC heat exchanger family also includes surface-type heat exchangers, known by the acronym SACOC for "Surface Air-Cooled Oil Cooler", which are generally arranged in the secondary vein of the turbomachine and which use the secondary airflow to cool the oil circulating in the turbomachine. However, SACOC heat exchangers generally have fins that continuously disturb the airflow and create additional pressure losses in the secondary vein. This impacts the performance of the turbomachine as well as the specific fuel consumption.

[0005] To overcome these drawbacks, some heat exchangers are buried in a compartment of the turbomachine. As illustrated in the Figure 1of the prior art, a heat exchanger A is integrated in a cavity B opening into a radially internal wall C of the secondary vein. A portion of the secondary air flow, taken from the secondary vein, passes through the buried heat exchanger A where it is reheated and is reinjected into the secondary vein. The exchanger A is in the form of a metal surface part allowing the passage of oil in machined channels D and carrying fins E which are intended to be crossed by the secondary air flow. A controlled scoop F, formed for example by a pivoting and / or translationally movable movable flap, is arranged at the inlet of the cavity B so as to extend into the secondary vein and to produce an adjustable air flow towards the buried heat exchanger A. An example of this heat exchanger is described in patent application EP-A1-2472067.

[0006] The movable flap of scoop F 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. In the closed position of the movable flap, the hot oil continues to circulate inside the heat exchanger, thus heating all the air trapped in it (the air flow is almost trapped if the movable flap is in the closed position) and in the cavity. The heated air flow is discharged into the secondary stream. The continuously circulating hot oil can reduce the life of the heat exchanger and the performance of the turbomachine is degraded. Thermal cycling is carried out on each flight even if the heat exchanger is not used to cool the oil.

[0007] There is therefore a need to overcome the above-mentioned drawbacks. Summary of the invention

[0008] The objective of the present invention is to provide a heat exchange system making it possible to optimize the integration of a heat exchanger in a cavity and to reduce pressure losses while maintaining the performance of the turbomachine throughout its operating life.

[0009] We achieve this objective in accordance with the invention by means of a heat exchange system for an aircraft turbomachine comprising: a cavity comprising an air inlet, a heat exchanger arranged in the cavity, the heat exchanger comprising a first circuit in which a first fluid supplied by a fluid supply circuit is capable of circulating, a movable flap mounted at the air inlet and moving between an open position allowing the circulation of the air flow in the cavity and a closed position preventing the circulation of the air flow in the cavity, a control device comprising at least one movable member intended to cause the movement of the movable flap, the control device being arranged in the fluid supply circuit of the heat exchanger, and being configured so as to authorize or prohibit the circulation of the first fluid towards the heat exchanger and to act simultaneously on the open or closed position of the movable shutter.

[0010] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the coupling of the position of the movable flap and the position of the movable member allows adaptation to the different flight phases of the turbomachine and the aircraft. The use of the heat exchanger in certain flight cases of the turbomachine makes it possible to increase its service life and possibly a weight saving. In particular, this configuration makes it possible to avoid overheating of the cavity in which the heat exchanger is installed, to reduce the thermal cyclane of the heat exchanger and the pressure losses.

[0011] The heat exchange system also includes one or more of the following features, taken alone or in combination: the control device is intended to be connected on the one hand to a supply line connected to the first circuit of the heat exchanger and on the other hand to a bypass line which bypasses the heat exchanger, said supply line being intended to be supplied by the supply circuit when the movable shutter occupies the open position and said bypass line being intended to be supplied by the supply circuit when the movable shutter occupies the closed position. the movable member moves between: --a first position allowing the circulation of the first fluid towards the heat exchanger and in which the movable shutter is in the open position, and --a second position allowing the circulation of the first fluid towards the bypass line and in which the movable shutter is in the closed position.the heat exchange system comprises means for measuring at least one determined parameter of the first fluid leaving the heat exchanger, according to the direction of circulation of the first fluid in the heat exchanger, and which are capable of being connected to an electronic control unit, the electronic control unit being configured so as to control the transition from one position to another of the mobile member as a function of the determined parameter.the control device comprises a body provided with a housing into which a first inlet orifice, a second inlet orifice, a first outlet orifice and a second outlet orifice open, the first and second inlet orifices being intended to be connected to the supply circuit, the first outlet orifice being intended to be connected to the first circuit and the second outlet orifice being intended to be connected to the bypass pipe, the movable member closing the second outlet orifice in the first position and closing the first outlet orifice in the second position. the movable member is capable of occupying at least one intermediate position in which the first fluid is capable of circulating towards the heat exchanger and towards the bypass pipe. the first fluid comprises oil. the determined parameter of the first fluid is the temperature of the first fluid at the outlet of the heat exchanger.the movable member comprises an actuating rod articulated to the movable shutter.

[0012] The invention also relates to a turbomachine module comprising an annular compartment around the longitudinal axis X, a fluid supply circuit and a heat exchange system having, according to any one of the aforementioned characteristics, the compartment comprising an annular wall which at least partly guides an air flow and the heat exchange system being arranged in the annular compartment and on the supply circuit, the air inlet of the cavity being arranged in the annular wall so as to be in fluid communication with the annular compartment.

[0013] The invention also relates to an aircraft turbomachine comprising a turbomachine module as mentioned above or a heat exchange system as described above.

[0014] The invention also relates to a method for regulating the circulation of a first fluid in a heat exchanger of a heat exchange system for a turbomachine, the heat exchanger being arranged in a cavity of a compartment of the turbomachine and the cavity being capable of being swept by an air flow, the method being characterized in that it comprises: - a step of supplying a first fluid into a fluid supply circuit of the turbomachine, - a step of arranging the heat exchanger and a control device on the supply circuit, - a regulation step so as to, simultaneously, authorize or prohibit the circulation of the air flow in the cavity and the circulation of the first fluid towards the heat exchanger.The method also one or more of the following features or steps, taken alone or in combination: - the regulation step comprises: -- a sub-step of moving the movable member into the first position to allow the circulation of oil to the first circuit of the heat exchanger or into the second position to allow the circulation of oil through the bypass duct, -- a sub-step of actuating the movable flap into an open position allowing the circulation of the air flow in the cavity and a closed position preventing the circulation of the air flow in the cavity, the position of the movable flap being a function of the position of the movable member. - a step of measuring a determined parameter of the first fluid and in that the moving step is carried out as a function at least of the reaching of a threshold of said predetermined parameter.- the measured determined parameter is a temperature representative of the temperature of the first fluid in the heat exchanger, measured continuously or discretely at regular intervals, and in that at each measurement, the regulation step performs at least one of the following steps before a consecutive measurement of the temperature: -- when the measured temperature is lower than at least one set temperature threshold, the movable member is controlled to move into the second position so as to supply the bypass pipe with the first fluid, -- when the measured temperature is equal to said set temperature threshold, the movable member is controlled to move into its previous position, and / or -- when the measured temperature is higher than said set temperature threshold, the movable member is controlled to move into the first position so as to supply the supply pipe with the first fluid to the heat exchanger.

[0015] The invention also relates to an aircraft comprising a heat exchange system or a turbomachine as described. Brief description of the figures

[0016] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which: [ Fig. 1 ] There Figure 1 is an axial sectional view of an example of a heat exchanger which is mounted in a cavity of a turbomachine according to the prior art; [ Fig. 2 ] There Figure 2 is a perspective view of an example of a turbomachine to which the invention applies; [ Fig. 3 ] There Figure 3is a schematic and axial sectional view of a heat exchange system mounted in a turbomachine module, the heat exchange system comprising a buried heat exchanger according to the invention; [ Fig. 4 ] There Figure 4 schematically illustrates an example of a control device intended to act on a movable flap and being in a position allowing the circulation of a fluid towards a heat exchanger according to the invention; [ Fig. 5 ] There Figure 5 schematically illustrates an example of a control device intended to act on a movable flap and being in a position preventing the circulation of a fluid in a heat exchanger according to the invention; [ Fig. 6 ] There Figure 6is a schematic view of an example of a control device allowing the circulation of a fluid towards a heat exchanger and towards a bypass pipe bypassing the heat exchanger, the flow rate of fluid allowed to circulate being identical according to the invention; [ Fig. 7 ] There Figure 7 is another embodiment of a control device allowing the circulation of oil to a heat exchanger and to a bypass line bypassing the heat exchanger, the flow rate of fluid allowed to circulate being different according to the invention; and [ Fig. 8 ] There figure 8 illustrates the main steps of a method for regulating a fluid in a heat exchanger installed in a cavity of a compartment of the turbomachine according to the invention. Detailed description of the invention

[0017] There Figure 1 has been described in the above.

[0018] There Figure 2shows an axial sectional view of a turbomachine 1 with longitudinal axis X to which the invention applies. The turbomachine 1 shown is a dual-flow turbomachine intended to be mounted on an aircraft. Of course, the invention is not limited to this type of turbomachine.

[0019] In the present invention, the terms “upstream” and “downstream” are defined in relation to the circulation of gases in the turbomachine 1 and here along the longitudinal axis X and with reference to the Figure 1 from left to right. The terms "radial", "internal" and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X. Similarly, a turbomachine generally consists of several modules which are manufactured independently of each other and which are then assembled together in such a way as to facilitate its assembly, disassembly and maintenance.

[0020] This dual-flow turbomachine 1 generally comprises a gas generator or gas turbine engine 2 upstream of which a fan 3 is mounted. The gas generator 2 comprises a gas compressor assembly (here comprising a low-pressure compressor 4a and a high-pressure compressor 4b), a combustion chamber 5 and a turbine assembly (here comprising a high-pressure turbine 6a and a low-pressure turbine 6b). Conventionally, the turbomachine comprises a low-pressure shaft 7 which connects the low-pressure compressor 4a and the low-pressure turbine 6b to form a low-pressure body and a high-pressure shaft 8 which connects the high-pressure compressor 4b and the high-pressure turbine 6a to form a high-pressure body. The low-pressure shaft 7, centered on the longitudinal axis, drives in the present example a fan shaft 9. A speed reducer 10 can be interposed, as here, between the fan shaft 9 and the low-pressure shaft 7.Rotating guide bearings 11, upstream and downstream, allow the low pressure shaft 7 to be guided in rotation relative to a fixed structure of the turbomachine.

[0021] The fan 3 is shrouded by a fan casing 12 carried by a nacelle 13 and generates a primary air flow F1 which circulates through the gas generator 2 in a primary vein 14 and a secondary air flow F2 which circulates in a secondary vein 15 around the gas generator 2. The secondary air flow F2 is ejected by a secondary nozzle 16 terminating the nacelle 13 while the primary air flow F1 is ejected outside the turbomachine via an ejection nozzle 17 located downstream of the gas generator 2.

[0022] The guide bearings 11 and the speed reducer 10 in this example of a turbomachine configuration must be lubricated and / or cooled to ensure good performance of the turbomachine. The power generated by them is dissipated in a fluid coming from a fluid supply source installed in the turbomachine and which makes it possible to lubricate and / or cool various components and / or equipment of the turbomachine. Of course, other equipment of the turbomachine generates a lot of heat which must be extracted from its environment.

[0023] In reference to the figures 2 And 3, the turbomachine 1 comprises a heat exchange system 20 which makes it possible to cool the fluid intended to lubricate and / or cool these members and / or equipment. The heat exchange system 20 comprises a heat exchanger 21 shown very schematically. The heat exchanger 21 is mounted in a compartment in which an air flow circulates. The compartment can be an inter-stream casing 18, the fan casing 12 or even the nacelle 13. The inter-stream casing 18 separates the primary stream 14 and the secondary stream 15. This inter-stream casing 18 carries a separation nozzle 19 upstream and the gas ejection nozzle 17 downstream.

[0024] On the Figure 3, the heat exchanger 21 is arranged in a cavity 22, around the longitudinal axis, which is intended to be crossed by an air flow, in particular the secondary air flow F2. In the present example, the cavity 22 is arranged in the inter-vein casing 18. The cavity 22 comprises an air inlet 23 which is in fluid communication with the secondary vein 15. The cavity 22 also comprises an air outlet 24 which is in fluid communication with the secondary vein 15. In the example shown, the air inlet 23, as well as the air outlet 24 are formed in a radially internal wall 25 of the inter-vein casing 18. The radially internal wall 25 is intended to guide at least in part the secondary air flow F2 in the secondary vein 15. The cavity 22 also extends over an angular sector, following a circumferential direction around the longitudinal axis X, of the order of 30°.

[0025] The heat exchanger 21 comprises a first circuit 26 in which a first fluid is able to circulate and a second circuit 27 in which a second fluid is able to circulate. The first fluid is an oil and the second fluid is the air flow circulating in the turbomachine and here a part of the secondary air flow taken from the secondary vein 15. The air flow constitutes the cold source intended to cool the hot oil heated by the organs / equipment of the turbomachine. The heat exchanger 21 is of the air / oil surface type.

[0026] Several oil channels 26a are arranged in the thickness of an inner wall and an outer wall along the radial axis in the heat exchanger 21. These oil channels 26a communicate with each other and form the first circuit 26. The latter comprises an inlet 26b and an outlet 26c. The second circuit 27 extends between the inner and outer walls of the heat exchanger 21. These walls are spaced radially from one another, forming a channel. The air flow circulates through the channel. Each of the walls comprising the channels 26a is swept by the air flow so as to carry out an exchange with them. The heat exchanger 21 may comprise a plurality of fins 27a each extending radially at least from one of the inner and outer walls. The fins make it possible to increase the contact surface with the secondary air flow to extract the calories.

[0027] The heat exchanger 21 is mounted on a fluid (oil) supply circuit 28 of the turbomachine 1. The oil supply circuit 28 comprises, generally and according to the direction of flow of the oil, an oil source 29, at least one supply pump 30 intended to allow the circulation of oil in the supply circuit 28 from the oil source 29, at least one filter 31, and at least one recirculation pump 32. The oil source 29 here comprises a reservoir 29a. The heat exchanger 21 is typically arranged downstream of the supply pump 30 and also upstream of the members and / or equipment to be lubricated and / or cooled. The latter are typically located in lubrication enclosures 33. The recirculation pump 32 allows the recirculation of the oil from the members and / or equipment to the reservoir 29a. The first circuit 26 of the heat exchanger is a portion of the supply circuit 28.

[0028] The heat exchange system 20 further comprises a controlled scoop 34, formed by a movable flap intended to authorize or prohibit the circulation of a portion of the secondary air flow in the cavity 22 and in particular through the heat exchanger 21. The movable flap 34 is arranged at the air inlet 23 of the cavity 22. More precisely, the movable flap 34 can move between an open position in which the air flow is authorized to circulate in the cavity (and also in the compartment or around the inter-vein casing 18) and a closed position in which the air flow is not authorized to circulate in the cavity 22 (the air flow circulates only in the compartment or around the inter-vein card (i.e. in the secondary vein 15).

[0029] Advantageously, the movable flap 34 is pivotally mounted around an axis 35 transverse to the longitudinal axis X. A pivot connection is provided between the movable flap 34 and a portion of the radially internal wall 25 of the inter-vein casing 18. The movable flap 34 also has dimensions corresponding substantially to those of the air inlet 23. In particular, the movable flap 34 extends over an angular sector of the order of 30° in the circumferential direction.

[0030] As can be seen on the Figure 3, the heat exchange system 20 comprises a control device 36 which is configured to act (prohibit or authorize) on the circulation of the first fluid (oil), towards the heat exchanger 2 (i.e. in the first oil circuit) and simultaneously on the position of the movable flap 34. More precisely still, the control device 36 is configured to associate the closed position of the movable flap 34 with a bypass pipe 37 bypassing the heat exchanger 21 to avoid a rise in temperature therein and in the cavity 22. The control device 36 is arranged in the supply circuit 28.

[0031] In reference to the Figure 4, the control device 36 is in the form of a distribution valve which comprises a body 38 provided with a housing 39 or bore and a movable member 40 moving in the housing 39 between a first position allowing the circulation of oil towards the heat exchanger 21 and a second position allowing the circulation of oil in the bypass pipe 37. In particular, in the second position, the oil is not allowed to circulate towards the heat exchanger 21. The movable member 40 is intended to drive or actuate the movement of the movable flap 34. For this, the movable member 40 comprises an actuating rod 41 whose free end 42 is fixed in an articulated manner to the movable flap. The actuating rod 41 extends at least partly outside the body 38.In this way, when the movable member 40 moves between its first position and its second position, the latter causes the movable shutter 34 to move into the open or closed position. According to an exemplary embodiment not shown, the free end 42 of the actuating rod 41 is articulated directly with the movable shutter. Alternatively and as illustrated in the . Figure 3, a connecting rod 43 comprises a first end 43a which is fixed in an articulated manner to the movable flap 34 and a second end 43b which is fixed to the free end 42 of the actuating rod 41 of the movable member 40. According to yet another alternative (not shown), a connecting rod and a movable part are arranged between the movable flap 34 and the movable member 40 to effect the change in position of the movable flap. In particular, the first end of the connecting rod is articulated with the movable flap 34 and the second end of the connecting rod is articulated to the movable part. The latter, in the form of a bracket for example, pivots about an axis transverse to the longitudinal axis of the turbomachine. The movable part is also articulated to the free end of the actuating rod 41.

[0032] In reference to the figures 4 to 5, the control device 36 is intended to be connected on the one hand to a first supply pipe 49 connected to the first circuit 26 of the heat exchanger 21 and on the other hand, to the bypass pipe 37 which bypasses the heat exchanger 21. In particular, the body 38 comprises a first inlet orifice 44, a second inlet orifice 45, a first outlet orifice 46 and a second outlet orifice 47 opening into the housing 39. The first and second inlet orifices 44, 45 are intended to be connected to the supply circuit 28. The first outlet orifice 41 is intended to be connected to the first circuit 26 of the heat exchanger 21. The movable member 40 defines in the body 38 a first chamber 48a and a second chamber 48b which are hermetically separated. The volume of the chambers 48a, 48b varies according to the movement of the movable member 40 inside the body 38.In the present example, the movable member 40 moves in a translational manner. As illustrated, the first inlet orifice 44 is in fluid communication with the first chamber 48a. The first outlet orifice 46 is also in fluid communication with the first chamber 48a. The first supply pipe 49 is arranged on the supply circuit 28 so as to connect the first circuit 26 of the exchanger 21 to the control device 36. The pipe 49 comprises an inlet 49a connected to the first outlet orifice 46 of the device 36 and an outlet 49b connected to the inlet 26b of the first circuit 26 of the heat exchanger 21.

[0033] The second inlet orifice 45 is in fluid communication with the second chamber 48b. The second outlet orifice 47 is also in fluid communication with the second chamber 48b. The bypass pipe 37 comprises an inlet 37a which is connected to the second outlet orifice 47 of the control device 36. This bypass pipe 37 also comprises an outlet 37b which is arranged downstream of the heat exchanger (downstream of the outlet 26c of the first circuit 26). More precisely, the outlet 37b is arranged between the reservoir 29a and the heat exchanger 21. The outlet 26c of the first circuit 26 is coupled to a second pipe 50 of the supply circuit 28.

[0034] The movement of the movable flap 34 is coupled to the circulation of fluid in the bypass pipe so as to avoid overheating of the cavity 22 in which the heat exchanger 21 is arranged and also to the circulation of fluid in the heat exchanger 21 itself (in the first circuit). For this purpose, when the movable member 40 occupies the first position (circulation of oil in the first circuit 26) then the movable flap 34 is in the open position. In this case, the oil circulating in the heat exchanger 21 is cooled by a portion of the secondary air flow passing through the heat exchanger 21. In this position as illustrated in the Figure 4 , the movable member 40 closes the second inlet orifice 45 and also the second outlet orifice 47.

[0035] Conversely, when the mobile member 40 of the control device 36 occupies the second position (circulation of oil in the bypass pipe 37), then the mobile flap 34 is in the closed position. There is no sampling of a part of the secondary air flow in the secondary vein 15, which optimizes the performance of the turbomachine, and the hot oil which comes from the members and / or equipment to be lubricated and / or cooled is redirected to the reservoir 29a so as to avoid an increase in the temperature in the heat exchanger 21 as well as in the cavity 22. In this position, as illustrated in the Figure 5 , the movable member 40 closes the first inlet orifice 44 and also the first outlet orifice 46.

[0036] Advantageously, the heat exchange system 20 comprises means 51 for measuring at least one determined parameter of the first fluid (oil) in the turbomachine 1. The measuring means 51 are connected to an electronic control unit 60 of the turbomachine. This electronic control unit 60 is configured to control the transition from one position to another of the mobile member 40 of the control device 36 as a function of the determined parameter. The means 51 for measuring the determined parameter may be a sensor, a probe, a thermocouple or any element capable of detecting a determined parameter in the turbomachine. The temperature of the oil at the outlet of the heat exchanger 21 is an example of a determined parameter. A measurement of the viscosity of the oil is also conceivable. As illustrated in the Figure 3, the measuring means 51 are installed on the pipe 50 of the oil supply circuit 28 and downstream of the heat exchanger 21. The electronic control unit 60 delivers a control order to the control device 36 when the measured temperature is higher, lower or reaches at least one temperature threshold to move from one position to another. Advantageously, but not limitingly, the temperature threshold is between 20°C and 100°C. The temperature threshold is recorded in a memory (not shown) of the electronic control unit 60. The first position of the movable member (open position of the movable flap) is considered to be a default position. That is to say that when the turbomachine is started, the movable flap 34 is open or opens and oil circulates towards the heat exchanger 21.When the measured temperature reaches or is lower than the temperature threshold, the movable member 40 switches to the second position to close the movable flap 34 and allow the circulation of oil towards the bypass pipe 37.

[0037] According to an alternative, several temperature thresholds are recorded in the memory of the electronic control unit 60. A first temperature threshold is associated with the first position of the movable member 40 or the opening position of the movable shutter 34. A second threshold is associated with the second position of the movable member 34 or the closing position of the movable shutter 34. The first temperature threshold can be 20°C and the second temperature threshold can be 100°C.

[0038] According to an embodiment illustrated on the Figure 6, the movable member 40 of the control device 36 can occupy an intermediate position. In this case the movable flap 34 has an intermediate opening angle in an intermediate position as well. In the present example, the intermediate position is located between the first position and the second position. The control device 36 is configured so as to have an oil flow rate at its outlet which is specific to each position of the movable flap. In particular, when the movable flap 34 is in the open position, all the oil flow circulates towards the heat exchanger 21. When the movable flap 34 is in the closed position all the oil flow circulates towards the bypass pipe 37. In the intermediate position, the control device 36 simultaneously authorizes an oil flow towards the heat exchanger 21 and towards the bypass pipe 37.The oil flow rate to the heat exchanger 21 is identical to the oil flow rate to the bypass pipe 37. The movable flap 34 also occupies its intermediate position located between the open position and the closed position. The first and second inlet ports 44, 45 and the first and second outlet ports 46, 47 are not blocked. Similarly, the intermediate position of the control device 36 is associated here with a third temperature threshold. The latter is between the first threshold and the second temperature threshold. Advantageously, the values ​​of the different thresholds are far apart or respect a certain hysteresis to avoid having flaps (oscillations) of the movable flap 34. For example, the third temperature threshold is 80°C.

[0039] Following an alternative shown on the Figure 7, when the control device 36 switches to the intermediate position, the flow rate of oil circulating towards the heat exchanger 21 is less than the flow rate of oil towards the bypass line 37. The flow rate of oil towards the heat exchanger 21 may correspond to 25% of the total flow rate of oil entering the control device 36 while the flow rate of oil towards the bypass line 37 may correspond to 75% of the total flow rate. For this purpose, the first inlet orifice 44 and the first outlet orifice 46 are partially blocked. Of course, the percentage of the flow rate distributed may be different.

[0040] Advantageously, but not limited to, the control device 36 is a hydraulic distributor which is mounted on the supply circuit 28 of the turbomachine. The distributor comprises a slide acting as a movable member.

[0041] We will present an example of a method 100 for regulating the circulation of oil in the heat exchanger 21 of the heat exchange system 20 as described above. The steps of the method are shown in the figure 8 The method firstly comprises a step 110 of supplying a first fluid (here oil) into a supply circuit 28. The method also comprises, before or after step 110, a step 120 of arranging the heat exchanger 21 and a control device 36 on the supply circuit 28. As we have seen and in particular on the Figure 3, the control device 36 is arranged, according to the circulation of the first fluid in the supply circuit 28, between the heat exchanger 21 and the reservoir 29a (or fluid source). The method 100 comprises a step of regulating or managing 130 in a differentiated manner (authorizing or prohibiting) and simultaneously the circulation of the air flow in the cavity 22 and the circulation of the first fluid towards the heat exchanger 21. The regulation step 130 comprises a sub-step 131 of moving the movable member 40 into the first position to authorize the circulation of the oil towards the first circuit 26 of the heat exchanger 21 (passing through the supply pipe 49) or into the second position to prohibit the circulation of oil towards the heat exchanger 21. In the second position, the oil is redirected towards the reservoir without passing through the heat exchanger 21.This step 130 also comprises a sub-step 132 of actuating the movable flap 34 which is a function of the position of the movable member 40. In the first position of the movable member 40, the movable flap 34 occupies the open position to allow the circulation of the air flow in the cavity 22. And in the second position of the movable member 40, the movable flap 34 occupies the closed position to prohibit the circulation of the air flow in the cavity. In particular, when the movable flap 34 occupies the open position, the supply pipe 49 is supplied by the supply circuit 28 and when the movable flap 34 occupies the closed position the bypass pipe 37 is supplied by the supply circuit 28.

[0042] The change of the position of the movable member 40 depends on a predetermined parameter of the first fluid. For this, the method 100 also comprises a step 140 of measuring a determined parameter (the temperature in or at the outlet of the heat exchanger) of the first fluid to carry out the displacement sub-step. For this purpose, the measuring means 51 send information relating to the temperature of the oil at the outlet of the exchanger 21. Each measured temperature is compared with the temperature threshold(s) recorded in the memory of the electronic control unit 60. When the measured temperature reaches, is lower than or is higher than one of the temperature thresholds, the electronic control unit 60 sends a control order to the control device 36.In particular, the control order controls the movement of the movable member 40 into the first position, into the second position, into its holding in position or possibly into the intermediate position. For example, the temperature of the first fluid in the heat exchanger, or at the outlet of the heat exchanger is measured continuously or discretely, at regular intervals. The regulation step carries out, at least before a consecutive measurement of the temperature, a step consisting in that when the measured temperature is lower than at least one set temperature threshold, the movable member 40 is controlled to move into the second position so as to supply the bypass pipe 37 with the first fluid.The regulation step can carry out, at least before a consecutive measurement of the temperature, a step consisting in that when the measured temperature is equal to said set temperature threshold, the movable member 40 is controlled to move into its previous position. The regulation step can carry out, at least before a consecutive measurement of the temperature, a step consisting in that when the measured temperature is greater than said set temperature threshold, the movable member 40 is controlled to move into the first position so as to supply the supply pipe 49 with the first fluid to the heat exchanger.

[0043] Thus, the closing of the movable flap 34 and the circulation of the oil in the bypass pipe 37 (bypassing the heat exchanger 21) makes it possible to reduce the thermal cycling in the heat exchanger and to lower the pressure losses in the first oil circuit. Such reductions allow a gain on the one hand, on the service life of the heat exchanger, and on the other hand, on the performance and efficiency of the latter and also of other members of the supply circuit 28. Similarly, the temperature to be supported by the cavity 22 can be weighted so as to obtain mass gains on the materials used (e.g. composites), in particular for the walls of the cavity 22 and those of the exchanger 21.

Claims

1. A heat exchange system (20) for an aircraft turbine engine (1) comprising: - a cavity (22) comprising an air intake (23), - a heat exchanger (21) arranged in the cavity (22), the heat exchanger (21) comprising a first circuit (26) through which a first fluid provided by a fluid supply circuit (28) is able to circulate, - a movable flap (34) mounted at the level of the air intake (23) and displacing between an opening position allowing the circulation of the airflow into the cavity (22) and a closing position preventing the circulation of the airflow into the cavity (22), - a control device (36) comprising at least one movable member (40) intended to cause the displacement of the movable flap (34), characterised in that the control device (36) is arranged in the fluid supply circuit (28) supplying fluid to the heat exchanger (21), and is configured so as, simultaneously, to allow or prevent the circulation of the first fluid towards the heat exchanger (21) and to act on the opening or closing position of the movable flap (34).

2. Heat exchange system (20) according to the preceding claim, characterised in that the control device (36) is intended to be connected on the one hand to a supply conduit (49) connected to the first circuit (26) of the heat exchanger (21) and on the other hand to a bypass conduit (37) which bypasses the heat exchanger (21), said supply conduit (49) being intended to be supplied by the supply circuit (28) when the movable flap (34) occupies the opening position and said bypass conduit (37) being intended to be supplied by the supply circuit (28) when the movable flap (34) occupies the closing position.

3. Heat exchange system (20) according to the preceding claim, characterised in that the movable member (40) displaces between: - a first position allowing the circulation of the first fluid towards the heat exchanger and in which the movable flap (34) is in the opening position, and - a second position allowing the circulation of the first fluid towards the bypass conduit (37) and in which the movable flap (34) is in the closing position.

4. Heat exchange system (20) according to one of the preceding claims, characterised in that it comprises means (51) for measuring at least one determined parameter of the first fluid at the outlet of the heat exchanger (61), depending on the circulation orientation of the first fluid in the heat exchanger (21), and which are capable of being connected to an electronic control unit (60), the electronic control unit (60) being configured so as to drive the passage from one position to another of the movable member (40) as a function of the determined parameter.

5. Heat exchange system (20) according to one of claims 3 to 4, characterised in that the control device (36) comprises a body (38) provided with a housing (39) into which a first inlet orifice (44), a second inlet orifice (45), a first outlet orifice (46) and a second outlet orifice (47) open, the first and second inlet orifices (44, 45) being intended to be connected to the supply circuit (28), the first outlet orifice (46) being intended to be connected to the first circuit (26) and the second outlet orifice (47) being intended to be connected to the bypass conduit (37), the movable member (40) sealing the second outlet orifice (47) in the first position and sealing the first outlet orifice (46) in the second position.

6. Heat exchange system (20) according to any one of the preceding claims, characterised in that the movable member (40) is adapted to occupy at least one intermediate position in which the first fluid is adapted to circulate towards the heat exchanger (21) and towards the bypass conduit (37).

7. A turbine engine module comprising an annular compartment (12, 13, 18) around the longitudinal axis X, a fluid supply circuit (28) and a heat exchange system (20) according to any of the preceding claims, the compartment comprising an annular wall (25) which at least partly guides an airflow and the heat exchange system (20) being arranged in the annular compartment (12, 13, 18) and on the supply circuit (28), the air intake (23) of the cavity (22) being arranged in the annular wall (25) so as to be in fluidic communication with the annular compartment.

8. An aircraft turbine engine (1) comprising a turbine engine module according to the preceding claim or a heat exchange system (20) according to any of claims 1 to 6.

9. A method for regulating the circulation of a first fluid through a heat exchanger (21) of a heat exchange system (20) for an aircraft turbine engine, the heat exchanger (21) being arranged in a cavity (22) of the heat exchange system and the cavity (22) being capable of being swept by an airflow circulating from an air intake (23) of the cavity (22), the method being characterised in that it comprises: - a step of providing (110) a first fluid into a fluid supply circuit (28) of the turbine engine, - a step of arranging (120) the heat exchanger (21) and a control device (36) on the supply circuit (28), the control device (36) comprising a movable member (34) intended to cause the displacement of a movable flap (34), mounted at the level of the air intake (23), between an opening position allowing the circulation of the airflow in the cavity (22) and a closing position preventing the circulation of the airflow in the cavity (22); and - a step of regulating (130) so as to simultaneously allow or prevent the circulation of the airflow in the cavity (22) and the circulation of the first fluid towards the heat exchanger and to act on the opening or closing position of the movable flap (34).

10. Method according to the preceding claim, characterised in that the regulation step (130) comprises: - a sub-step of displacing (131) the movable member (40) to the first position to allow the oil to circulate towards the first circuit (26) of the heat exchanger (21) or to the second position to allow the oil to circulate towards the bypass conduit, and - a sub-step of actuating (132) the movable flap (34) in the opening position allowing the airflow to circulate in the cavity (22) and the closing position preventing the airflow from circulating in the cavity, the position of the movable flap (34) being a function of the position of the movable member.

11. Method according to the preceding claim, characterised in that it comprises a step of measuring (140) a determined parameter of the first fluid and in that the displacement step (131) is carried out as a function of at least the reaching of a threshold of said predetermined parameter.

12. Method according to the preceding claim, characterised in that the determined parameter measured is a temperature representative of the temperature of the first fluid in the heat exchanger, measured continuously or discretely at regular intervals, and in that at each measurement the regulation step (130) performs at least one of the following steps, prior to a subsequent measurement of the temperature: - when the measured temperature is below at least one setpoint temperature threshold, the movable member (40) is driven to displace to the second position so as to supply the bypass conduit (37) with the first fluid, - when the measured temperature is equal to said setpoint temperature threshold, the movable member (40) is driven to displace to its previous position, and / or - when the measured temperature is above said setpoint temperature threshold, the movable member (40) is driven to displace to the first position so as to supply the supply conduit (49) with the first fluid towards the heat exchanger (21).