Turbine comprising heat exchanger between fuel circuit and two lubricant circuits
The turbomachine's integrated heat exchanger with parallel fuel and lubricant circuits addresses the challenge of insufficient cooling by optimizing heat exchange and reducing costs and space, ensuring efficient lubricant cooling across varying flight conditions.
Patent Information
- Application Number
- CN202380038640.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-05
- Filing Date
- 2023-05-03
- Publication Date
- 2024-12-13
AI Technical Summary
There is a need for better management of fluid cooling in turbines, as traditional cooling sources like fuel and outside air may not be sufficient, especially in scenarios where fuel is scarce and flight conditions are unfavorable.
A turbomachine with a heat exchanger that integrates two ducts for a fuel circuit and two channels for lubricant circuits, allowing for thermal contact and parallel flow configurations to enhance heat exchange, including options for countercurrent and concurrent flow directions, and honeycomb structures for optimized heat distribution.
This design reduces manufacturing costs, mass, and space requirements while effectively utilizing all available cooling sources to manage lubricant cooling needs based on flight conditions.
Smart Images
Figure CN119137360A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to cooling of fluids in turbomachines. Background Art
[0002] In a turbine, some fluids (including, for example, engine oil or generator oil) need to be cooled. Turbine fuel can be used as a cooling source. As the engine consumes less and less fuel, fuel becomes less and less abundant, so another cooling source may become necessary. Outside air can be used, but for some flight conditions, this second cooling source may not be sufficient. Therefore, there is a need to better manage fluid cooling in turbines. Summary of the invention
[0003] One object of the invention is to propose a turbomachine that enables better management of the cooling of the fluid.
[0004] This object is achieved within the framework of the invention by a turbomachine comprising: a heat exchanger; a first circuit of a first fluid, the first circuit comprising two ducts in the heat exchanger; a second circuit of a second fluid; and a third circuit of a third fluid, each of the second circuit and the third circuit comprising a channel in the heat exchanger, each channel adjoining one of the ducts so as to be in thermal contact with one of the ducts, the channels adjoining one another so as to be in thermal contact with one another,
[0005] The heat exchanger comprises a section in which the ducts and the channels are partially parallel to one another.
[0006] This system / method is advantageously and optionally supplemented by the following features, taken alone or in combination:
[0007] - the first fluid is a fuel, the second fluid and the third fluid are lubricants;
[0008] - a high-pressure body, a high-pressure generator driven by the shaft of the high-pressure body, a low-pressure body, and a low-pressure generator driven by the shaft of the low-pressure body, the lubrication circuit being an oil circuit of the high-pressure generator and an oil circuit of the low-pressure generator;
[0009] - each conduit abuts one of the channels so as to be in thermal contact with one of the channels;
[0010] - the heat exchanger is configured so that the fuel flows in the conduit in a direction opposite to the direction of flow of the lubricant in the channel;
[0011] - the heat exchanger is configured so that the fuel flows in one of the conduits in a direction opposite to the direction of flow of the fuel in another of the conduits;
[0012] - the cross-sections of the duct and the channel comprise circular walls having the same centre;
[0013] - the cross-section of each of the conduit and the channel has a polygonal profile, the profile of the channel and the profile of the conduit having the same number of sides;
[0014] The fuel circuit comprises a plurality of ducts in the heat exchanger and each lubricant circuit comprises a plurality of channels in the heat exchanger, the ducts and channels forming a honeycomb structure, the exchanger being configured such that no two channels of the same lubricant circuit are adjacent and no two ducts are adjacent.
[0015] The invention also relates to a turbine comprising the type just described.
[0016] The invention finally relates to a method for heat exchange in a turbine, the method comprising: a step of forming two first flows of a first fluid, a step of forming a second flow of a second fluid and a third flow of a third fluid, the second flow and the third flow being in thermal contact with each other, the two first flows, the second flow and the third flow flowing in flow directions locally parallel to each other, each of the second flow and the third flow being in thermal contact with one of the two first flows.
[0017] This method is advantageously and optionally supplemented by the following feature: the first fluid is a fuel and the second and third fluids are lubricants. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other features and advantages of the present invention will emerge from the following description, which is purely illustrative and non-limiting and should be read in conjunction with the accompanying drawings, in which:
[0019] - Figure 1 is a schematic diagram of a turbine;
[0020] - Figure 2 is a schematic diagram of a heat exchanger according to one embodiment of the present invention;
[0021] - Figure 3 and Figure 4 are schematic cross sections of heat exchangers according to two embodiments of the present invention. DETAILED DESCRIPTION
[0022] Turbine - General Introduction
[0023] Reference Figure 1 , schematically shows a turbomachine, more specifically, an axial turbofan engine 1. The turbojet engine 1 shown extends along an axis Δ and comprises, in order in the flow direction of the gas in the turbomachine, a fan 2, a compression section (the compression section may include a low-pressure compressor 3 and a high-pressure compressor 4), a combustion chamber 5, and a turbine section (the turbine section may include a high-pressure turbine 6, a low-pressure turbine 7 and an exhaust nozzle).
[0024] The fan 2 and the low-pressure compressor 3 are driven to rotate by the low-pressure turbine 7 via a first transmission shaft 9 , while the high-pressure compressor 4 is driven to rotate by the high-pressure turbine 6 via a second transmission shaft 10 .
[0025] In operation, the air flow compressed by the low-pressure compressor 3 and the high-pressure compressor 4 feeds the combustion in the combustion chamber 5, the expansion of the combustion gases in the combustion chamber drives the high-pressure turbine 6 and the low-pressure turbine 7. The air propelled by the fan 2 and the combustion gases leaving the turbojet 1 through the exhaust nozzles located downstream of the turbines 6, 7 exert a reaction thrust on the turbojet 1 and, through the turbojet, on a vehicle or machine, such as an aircraft (not shown).
[0026] Heat Exchanger
[0027] about Figure 2 , the turbine 1 comprises a heat exchanger 11 configured to ensure heat exchange between the different fluid circuits involved in the operation of the turbine.
[0028] The turbine comprises a first circuit 13 of a first fluid passing through a heat exchanger 11 .
[0029] More specifically, the first circuit comprises two ducts 31 , 33 in the heat exchanger.
[0030] In a section of the heat exchanger, or even in the entire heat exchanger, the two ducts are locally parallel. This means that the ducts are:
[0031] - straight and parallel, or
[0032] - curved, and for each first section of the channel defining a first straight flow direction, the second channel comprises a second section closest to the first section, the second section defining a second straight flow direction parallel to the first direction.
[0033] For example, the two ducts 31 , 33 are straight and extend parallel to the direction A, so that the fuel flow passing through the ducts 31 , 33 flows parallel to the direction A.
[0034] The first circuit may be, for example, a fuel circuit 13 which comprises in particular a fuel circulation system and a fuel metering system for supplying the combustion chambers.
[0035] Figure 2 The fuel circuit 13 is shown, which is usually an open circuit. This circuit is in contact with a tank 21, which is usually located outside the turbine, for example in the wing of an aircraft. The fuel circuit 13 may include a pumping system 23 (or circulation system) configured to draw fuel from the tank to the turbine and circulate the fuel to the heat exchanger 11.
[0036] The fuel circuit may also include a metering system 25 configured to regulate the flow of fuel delivered to the combustion chamber 27 .
[0037] The first loop can also be a supercritical CO2 loop, a heat pump loop, a dihydrogen loop, a heat transfer fluid loop, etc.
[0038] The turbine also comprises a second circuit 15 for a second fluid and a third circuit 17 for a third fluid.
[0039] Each of the second circuit and the third circuit passes through the heat exchanger 11. More specifically, each of the second circuit and the third circuit includes a channel 51, 71 in the heat exchanger.
[0040] In sections of the heat exchanger, or even in the entire heat exchanger, the two channels 51 , 71 are locally parallel.
[0041] The second circuit 15 and the third circuit 17 may be, for example, two lubricant circuits 15, 17. Each of the second circuit and the third circuit comprises in particular a tank and a system for circulating the lubricant. As a variant, the lubricant circuits 15 and 17 may constitute separate sections of a single overall circuit of the same lubricant, for example parallel sections with the same inlet and the same outlet.
[0042] In a turbomachine comprising a fan reducer, the lubricant circuit may in particular be an engine oil circuit and an oil circuit of the reducer.
[0043] In a turbomachine comprising a high-pressure body and a low-pressure body and a high-pressure generator and a low-pressure generator, the lubricant circuit may in particular be an oil circuit of the high-pressure generator driven by a first transmission shaft 10 of the high-pressure body and an oil circuit of the low-pressure generator driven by a second transmission shaft 9 of the low-pressure body. Each of these generators generates electrical energy from the rotational movement of the shaft driving the generator. The lubrication circuit required by each of these generators needs to be cooled.
[0044] In a turbine including a fan reducer and a high-pressure body, a low-pressure body, a high-pressure generator and a low-pressure generator, the lubricant circuit can be selected from an engine oil circuit, an oil circuit of the reducer, an oil circuit of the high-pressure generator and an oil circuit of the low-pressure generator, the high-pressure generator is driven by the shaft of the high-pressure body, and the low-pressure generator is driven by the shaft of the low-pressure body.
[0045] The second loop or the third loop can also be a loop of a supercritical CO2 loop, a heat pump loop, a dihydrogen loop, a heat transfer fluid loop, etc.
[0046] The ducts 31 , 33 and the channels 51 , 71 are locally parallel to one another in sections of the heat exchanger or even in the entire heat exchanger.
[0047] In particular, preferably, the ducts and channels are curved in order to limit the space requirements of the heat exchanger or to adapt the shape of the heat exchanger to constraints related to the direct environment of the exchanger or to constraints related to the installation of the heat exchanger in the turbine. The heat exchanger 11 is configured so that each channel is in thermal contact with one of the ducts and two channels are in thermal contact with each other.
[0048] Each channel 51 , 71 abuts one of the conduits 31 , 33 so as to be in thermal contact with one of the conduits 31 , 33 .
[0049] The channels 51 , 71 abut each other to be in thermal contact with each other.
[0050] The proximity of adjacent channels or ducts and the material of the exchanger separating the adjacent channels or ducts enables heat exchange between the fuel / lubricant flows and between the lubricant flows.
[0051] By enabling heat exchange between two independent lubricant circuits, a single heat exchanger can be used instead of two exchangers. This makes it possible, among other things, to reduce manufacturing costs, the mass of the turbine and the space requirements.
[0052] Furthermore, depending on the flight point, one of the flows of the second or third circuit can be used as a heat sink.
[0053] Optionally, each conduit 31 , 33 also abuts one of the channels 51 , 71 so as to be in thermal contact with that channel.
[0054] The heat exchanger 11 can be adapted according to different fluid flow configurations.
[0055] In a first variant, the exchanger 11 is configured so that the fuel flows in the ducts 31, 33 in a direction opposite to the direction of flow of the lubricant in the channels 51, 71. In this first variant:
[0056] - the fuel flows through the two conduits in the same first direction, and
[0057] The lubricant flows through the two channels in the same second direction opposite to the first direction.
[0058] In a second variation, the heat exchanger 11 is configured so that the fuel flows in one of the conduits in a direction opposite to the direction in which the fuel flows in the other of the conduits.
[0059] The fuel flows through the conduit in the opposite direction. In this second variant:
[0060] - The lubricant can flow through both channels in the same direction, or
[0061] The lubricant may flow through one of the two channels in a first direction, and the lubricant may flow through the other of the two channels in a second direction opposite to the first direction.
[0062] Other variants can be envisaged with regard to the direction of circulation of the flows in the exchanger. In general, the relative circulation of the flows is defined as a function of the power to be exchanged between the flows. For example, if it is most often necessary to ensure that the heat exchange between the first lubricant flow and the fuel flow is greater than the heat exchange between the second lubricant flow and the fuel flow, the first lubricant flow can be placed in countercurrent with respect to the fuel flow and the second lubricant flow. In this case:
[0063] - the fuel flows through the two ducts in the same first direction,
[0064] a first lubricant flow flows through one of the two channels in a second direction opposite to the first direction, and
[0065] A second lubricant flow flows through the other of the two channels in the same first direction.
[0066] Shape of ducts and channels
[0067] The adjoining between two channels or ducts can be achieved in different ways.
[0068] In the first embodiment, regarding Figure 3 , the cross-sections of the ducts 31, 33 and the channels 51, 71 include circular walls having the same center.
[0069] The expression "cross section" refers to a cutting plane perpendicular to the extension direction A of the conduits 31, 33 and channels 51, 71, which defines the flow direction of the fluid through the channels and conduits. The extension direction is also the direction in which the channels and conduits are parallel to each other.
[0070] In a plane perpendicular to the direction A, the exchanger comprises four circular walls 41, 43, 45 and 47. The centres of these walls are identical and the walls are therefore concentric.
[0071] The first wall 41 having a smaller diameter defines the duct 31 on the inner side. In other words, the fuel flow passing through the duct 31 flows within the first circular wall 41.
[0072] The second wall 43 directly surrounds the first wall 41, that is, the diameter of the second wall 43 is larger than the diameter of the first wall 41, and the second wall faces the first wall 41. The annular cavity between the walls 41 and 43 defines the passage 51. In other words, the lubricant flow flowing through the passage 51 flows inside the second circular wall 43 and outside the first wall 41.
[0073] The third wall 45 directly surrounds the second wall 43, that is, the diameter of the third wall 45 is larger than the diameter of the second wall 43, and the third wall faces the second wall 43. The annular cavity between the walls 43 and 45 defines the passage 71. In other words, the lubricant flow flowing through the passage 71 flows inside the third circular wall 45 and outside the second wall 43.
[0074] The fourth wall 47 directly surrounds the third wall 45, that is, the diameter of the fourth wall 47 is greater than the diameter of the third wall 45, and the fourth wall faces the third wall 45. The annular cavity between the walls 45 and 47 defines the duct 33. In other words, the lubricant flow flowing through the duct 33 flows inside the fourth circular wall 47 and outside the third wall 45.
[0075] In a second embodiment, the cross-sections of the duct and the channel each have a polygonal profile, the profile of the channel and the profile of the duct having the same number of sides.
[0076] In a plane perpendicular to direction A, the exchanger comprises distinct straight walls defining the polygonal outline of the ducts and channels.
[0077] For example, the outline of each channel or conduit is triangular. Some straight walls (i.e. some sides of the triangle) can separate a channel from another channel or separate a channel from a conduit. Such sides can make two channels in thermal contact or make a channel in thermal contact with a conduit.
[0078] For example, the outline of each channel or conduit is a rectangle. Some straight walls (i.e. some sides of the rectangle) can separate a channel from another channel or separate a channel from a conduit. Such sides can make two channels in thermal contact or make a channel in thermal contact with a conduit.
[0079] In About Figure 4 In a third example, the outline of each channel or conduit is hexagonal, and the different hexagons defined are all of the same size.
[0080] In this third example, the fuel circuit comprises a plurality of conduits 35 in a heat exchanger. Figure 4 In the figure, the ducts are colored with the same grayscale.
[0081] Each lubricant circuit comprises a plurality of channels in the heat exchanger, respectively a channel 53 for the first lubricant circuit and a channel 73 for the second lubricant circuit. The channel 53 is colored in the same gray level darker than for the conduit 35. Figure 4 , channel 73 is colored with the same gray level that is darker than the gray level used for channel 53.
[0082] The ducts 35 and the channels 53, 73 form a honeycomb structure.
[0083] The exchanger can be constructed so that two channels of the same lubricant circuit do not adjoin and two conduits do not adjoin. Figure 4 is shown, and in this case:
[0084] each duct 35 is adjacent to one, two or three channels 53 and to one, two or three channels 73,
[0085] - Each channel 53 is adjacent to one, two or three conduits 35 and to one, two or three channels 73, and
[0086] Each channel 73 adjoins one, two or three ducts 35 and one, two or three channels 53 .
[0087] In this case, the heat exchange surfaces within the heat exchanger are evenly distributed between the different fuel / first lubricant pairs, fuel / second lubricant pairs and first lubricant / second lubricant pairs.
[0088] In another configuration of the exchanger with a honeycomb structure, the heat exchange surface of one of the pairs can also be enlarged compared to the heat exchange surfaces of the other two pairs.For this purpose, the conduits can be replaced by channels, and the channels for the first lubricant can be replaced by channels for the second lubricant.
[0089] The exchangers of different shapes mentioned here can in particular be produced by additive manufacturing. The exchangers of different shapes can also be produced according to more conventional manufacturing methods.
[0090] Heat exchange method
[0091] A turbomachine comprising a heat exchanger as presented above enables the implementation of the method according to the invention for exchanging heat between two lubricant circuits and a fuel circuit.
[0092] One embodiment of this method will now be presented.
[0093] During the first step E1 of the method, two first flows of a first fluid are formed. More specifically, the circuit of the first fluid is configured to circulate the first fluid according to two separate and partially parallel flows. These two flows flow, for example, through two ducts 31 , 35 of a first fuel circuit inside the heat exchanger 11 .
[0094] During a second step E2 of the method, a second flow of a second fluid and a third flow of a third fluid are formed.
[0095] More specifically, each circuit of the second fluid and of the third fluid is configured to circulate the second fluid or the third fluid according to two separate and partially parallel flows.
[0096] The two flows flow, for example, through two channels 51 , 71 , each channel being included in one of the second or third circuits within the heat exchanger 11 .
[0097] The second and third flows are in thermal contact. This is obtained in particular by applying adjacent channels 51, 71. The thickness and nature of the material separating the channels 51, 71 in the heat exchanger are adapted to enable heat exchange between the second and third flows.
[0098] The two first flows, the second flow and the third flow flow along flow directions which are locally parallel to each other.
[0099] In addition, each of the second and third flows is in thermal contact with one of the two first flows. This is obtained in particular by having each channel 51, 71 abutting against one of the ducts 31, 33. The thickness and nature of the material separating the channels and ducts in the heat exchanger are adapted to enable heat exchange.
[0100] A preferred example corresponds to a case in which the first fluid is a fuel and the second and third fluids are lubricants.
[0101] In this preferred embodiment, the fuel flow always acts as a heat sink within the exchanger regardless of the flight point.
[0102] On the other hand, the lubricant flow can change its effect depending on the flight point.
[0103] Consider a turbine comprising a high pressure body, a low pressure body, a high pressure generator driven by the shaft of the high pressure body and a low pressure generator driven by the shaft of the low pressure body. The lubricant circuit passing through the heat exchanger is selected as the oil circuit of the high pressure generator and the oil circuit of the low pressure generator.
[0104] The result is that these lubrication circuits have different cooling requirements depending on the operating point of the turbomachine or aircraft.
[0105] To illustrate the previous point, consider as an example a first operating point for which the aircraft is on the ground on a hot day. In this case, the lubrication circuit of the low-pressure generator requires cooling, while the lubrication circuit of the high-pressure generator does not. For this case, within the heat exchanger, the lubrication circuit of the low-pressure generator acts as a heat source, while the lubrication circuit of the high-pressure generator acts as a heat sink.
[0106] Still as an example, consider a second operating point corresponding to the situation where the aircraft is in maximum climb (usually after taking off and reaching a safe altitude). In this case, the lubrication circuit of the high-pressure generator needs to be cooled, while the lubrication circuit of the low-pressure generator does not need to be cooled. For this case, in the heat exchanger, the lubrication circuit of the high-pressure generator acts as a heat source, while the lubrication circuit of the low-pressure generator acts as a heat sink.
[0107] Therefore, since the heat exchanger enables heat exchange between the three fluids, all available cooling sources can be utilized to cool the lubricant flow.
Claims
1. A turbine, comprising: - a heat exchanger (11), - a first circuit (13) of a first fluid, said first circuit (13) comprising two ducts (31, 33) in said heat exchanger (11), - a second circuit (15) of a second fluid, and - a third circuit (17) of a third fluid, each of the second circuit and the third circuit comprising a channel (51, 71) in the heat exchanger (11), each channel (51, 71) being adjacent to one of the ducts (31, 33) so as to be in thermal contact with one of the ducts (31, 33), the channels (51, 71) being adjacent to each other so as to be in thermal contact with each other, The heat exchanger (11) comprises a section in which the ducts (31, 33) and the channels (51, 71) are partially parallel to each other.
2. The turbine according to claim 1, wherein: The first fluid is a fuel, and the second and third fluids are lubricants.
3. The turbine according to claim 2, comprising a high-pressure body, a high-pressure generator driven by the shaft of the high-pressure body, a low-pressure body, and a low-pressure generator driven by the shaft of the low-pressure body, and the lubrication circuit is an oil circuit of the high-pressure generator and an oil circuit of the low-pressure generator.
4. The turbine according to claim 2 or 3, wherein: Each conduit (31, 33) is adjacent to one of the channels (51, 71) so as to be in thermal contact with one of the channels (51, 71).
5. The turbine according to any one of claims 2 to 4, wherein: The heat exchanger (11) is configured such that the fuel flows in the conduit (31, 33) in a direction opposite to a direction in which the lubricant flows in the channel (51, 71).
6. A turbine according to any one of claims 2 to 4, wherein: The heat exchanger (11) is configured such that the fuel flows in one of the conduits in a direction opposite to a direction in which the fuel flows in another of the conduits.
7. A turbine according to any one of claims 2 to 6, wherein: The cross-sections of the duct (31, 33) and the channel (51, 71) include circular walls having the same center.
8. A turbine according to any one of claims 2 to 6, wherein: The cross-sections of each of the conduit and the channel have a polygonal profile, and the profile of the channel and the profile of the conduit have the same number of sides.
9. The turbine according to claim 8, wherein: The fuel circuit comprises a plurality of conduits in the heat exchanger and each lubricant circuit comprises a plurality of channels in the heat exchanger, the conduits and the channels forming a honeycomb structure, the exchanger being configured such that no two channels of the same lubricant circuit are adjacent and no two conduits are adjacent.
10. An aircraft comprising a turbine according to any one of the preceding claims.
11. A heat exchange method in a turbine, the heat exchange method comprising: the step of forming two first flows of a first fluid, the step of forming a second flow of a second fluid and a third flow of a third fluid, said second flow and said third flow being in thermal contact with each other, The two first flows, the second flow and the third flow flow in flow directions that are locally parallel to each other, and each of the second flow and the third flow is in thermal contact with one of the two first flows.
12. The heat exchange method according to claim 11, wherein: The first fluid is a fuel, and the second and third fluids are lubricants.