Aeronautical turbomachine powered by hydrogen or other cryogenically stored fuel

Abstract

The invention relates to a hydrogen-powered aeronautical turbomachine comprising a turbine, a heat exchanger (200a) having a hollow wall (202) whose interior (302), delimited by a first surface (206), defines a first conduit (302) for the passage of a cooling fluid (R). The wall (202) adjoins, via a second liquid water condensation surface (205), a space (204) separated from the interior (302) and in contact with the exhaust gas (G). The surface (205) has a downstream edge (304) for recovering the liquid water, and a gravity-fed liquid water collector (305) is connected to the downstream edge (304). The downstream edge (304) and the collector (305) are configured to collect the liquid and condensed water present on the second surface (205). (See Figure 3A for abbreviations.)

Description

Description Title of the invention: Hydrogen-powered aeronautical turbomachine or other fuel stored cryogenically

[0001] — The invention relates to an aeronautical turbomachine using hydrogen or other com- fuel stored cryogenically.

[0002] — The field of the invention relates to aircraft turbomachines, in particular turbojets or turboprops.

[0003] — Turbomachines having hydrogen or another fuel as fuel stored cryogenically require a heat exchanger to warm up hydrogen or other fuel stored cryogenically in order to do so change from liquid to gaseous state and bring it to compatible conditions of the injection.

[0004] — Turbomachines used for aircraft propulsion emit particles and water vapor, generating condensation trails. The impact of these condensation trails condensation on the climate is not yet fully quantified, but it could be comparable to that of carbon dioxide emissions for aviation. As part of of an attempt to decarbonize aviation, the path of burning di- hydrogen is being studied. The positive impact of this fuel change is the re- placement of carbon dioxide as a combustion product by water, as well as the almost total elimination of particles and soot emitted by engines.

[0005] — On the other hand, hydrogen engines would produce 2.6 times more water vapor at the same power, compared to a conventional kerosene engine. The impact on the climate of water condensation trails from combustion hydrogen could be prohibitive for this new technology by annihilating to- also the benefit of fuel decarbonization.

[0006] — The invention aims to obtain an aeronautical turbomachine using hydrogen or other com- fuel stored cryogenically, reducing the impact of water production from the combustion of hydrogen or other fuel stored in a cryogenic and integrating well with the turbomachine without significantly increasing its en- space requirement in addition to a heat exchanger and without significantly reducing the turbomachine thrust.

[0007] — To this end, a first object of the invention is an aeronautical turbomachine with hydrogen or other fuel stored cryogenically, comprising a turbine, comprising a casing delimiting an annular gas outlet duct exhaust of the turbomachine, containing water vapor, a heat exchanger, located downstream of the turbine, characterized in that the heat exchanger comprises at least one hollow wall, the interior of which, delimited by at least a first surface of the hollow wall, delimits a first conduit for the passage of a cooling fluid, the hollow wall adjoining by a second liquid water condensation surface a space, which is separated from the interior of the hollow wall, which is delimited by the second liquid water condensation surface and which is in contact with the exhaust gas of the turbomachine, the second surface of condensation of the liquid water belonging to the hollow wall and being distinct from the first surface, the second condensation surface of the heat exchanger comprising at least one downstream edge for recovering liquid water, the heat exchanger comprising a gravity-fed liquid water collector, which is connected to the downstream recovery edge below it, the downstream recovery edge and the liquid water collector being configured to collect the liquid and condensed water present on the second condensation surface. The invention thus makes it possible to capture part of the water vapor before it leaves the engine to prevent it from exiting directly in the form of condensation trail to the outside. The second surface(s) of the heat exchanger forms a surface condenser, which has the advantage of limiting the pressure losses of the combustion gas flow when these pass through the exchanger and therefore of not significantly reducing the thrust. The water capture is carried out semi-passively and located at a location limiting the impact of the capture on the engine performance. According to one embodiment of the invention, the heat exchanger comprises an internal wall, an external wall surrounding the internal wall and connecting walls fixed between the internal wall and the external wall, the inner wall and / or the outer wall and / or the connecting walls being hollow and having said first surfaces respectively delimiting a first conduit for the passage of a cooling fluid and / or a second conduit for the passage of a cooling fluid and / or third conduits for the passage of a cooling fluid, the inner wall, the outer wall and the connecting walls being integrated into the rear casing and having said second liquid water condensation surfaces, delimiting exhaust gas passage passage sectors, which are located in the annular exhaust gas outlet duct. According to one embodiment of the invention, the rear casing comprises an annular inner wall internally delimiting the annular exhaust gas outlet duct, the hollow wall of the exchanger is located downstream of the rear casing, the space being located downstream of the annular exhaust gas outlet duct. According to one embodiment of the invention, the rear casing comprises an annular outer wall and an annular inner wall, which delimit between them the annular exhaust gas outlet duct, the hollow wall of the exchanger is located downstream of the rear casing, the space being located downstream of the annular exhaust gas outlet duct. According to one embodiment of the invention, the second liquid water condensation surface is located on an internal side of the hollow wall of the exchanger, this internal side of the hollow wall being surrounded by the interior of the hollow wall, the exhaust gas passage space being surrounded by the hollow wall and by the first cooling fluid passage duct, an outer side of the hollow wall surrounding the first coolant passage duct, the inner side of the hollow wall and the exhaust gas passage space, at least one inlet is provided in the inner side of the hollow wall to admit exhaust gases into the space, at least one outlet is provided in the external side of the hollow wall to discharge the exhaust gases, the outlet being located further downstream than the inlet. According to one embodiment of the invention, the second liquid water condensation surface is located on an internal side of the hollow wall of the exchanger, this internal side of the hollow wall being surrounded by the interior of the hollow wall, the exhaust gas passage space being surrounded by the hollow wall and by the first cooling fluid passage duct, an outer side of the hollow wall surrounding the first coolant passage duct, the inner side of the hollow wall and the exhaust gas passage space, at least one inlet is provided in the inner side of the hollow wall to admit exhaust gases into the space, at least one outlet is provided in the inner side of the hollow wall to discharge the exhaust gases, the outlet being located further downstream than the inlet. According to one embodiment of the invention, the downstream recovery edge comprises a network of gutters converging to the liquid water collector. According to one embodiment of the invention, the downstream recovery edge comprises on the downstream part of the internal wall or on the internal side at least one internal gutter for the flow of liquid water, the downstream recovery edge comprises on the downstream part of the external wall or on the internal side at least one external gutter for the flow of liquid water. According to one embodiment of the invention, the downstream recovery edge comprises on the downstream part of each connecting wall at least one radial gutter for the flow of liquid water. According to one embodiment of the invention, the radial gutter for the flow of liquid water from each connecting wall is delimited by an upstream spout forming an acute angle between each external condensation surface of the connecting wall and an intermediate surface connecting the two external condensation surfaces of the connecting wall to each other, the upstream spouts and the intermediate surface delimiting upstream the radial gutter of liquid water flow, a downstream gutter bottom surface being provided at a distance and downstream of the intermediate surface and delimiting downstream the radial gutter for the flow of liquid water. According to one embodiment of the invention, an external radial opening for collecting a portion of the exhaust gases in the radial liquid water flow gutter is arranged between the upstream spouts and the downstream surface of the gutter bottom. According to one embodiment of the invention, the downstream surface of the gutter bottom occupies a width smaller than a width of the intermediate surface. According to one embodiment of the invention, the downstream surface of the gutter bottom is connected by its upstream ends to an upstream non-return rim. According to one embodiment of the invention, the liquid water collector is connected to a pneumatic water pressurization system to eject the water contained in the collector through ejection nozzles in the form of pressurized droplets to the outside. According to one embodiment of the invention, the liquid water collector is connected to a flushing device, configured to release a determined volume of water to the outside when the liquid water reaches this determined volume in the liquid water collector. According to one embodiment of the invention, the liquid water collector is connected to nozzles for continuously discharging the collector water to the outside. According to one embodiment of the invention, the turbomachine comprises a valve for regulating or cutting off the flow of exhaust gases upstream of the heat exchanger. According to one embodiment of the invention, the cooling fluid is hydrogen used as fuel for the turbomachine, or another cryogenically stored fuel used as fuel for the turbomachine or a ca- carrier. According to one embodiment of the invention, the first cooling fluid passage conduit, the second cooling fluid passage conduit and the third cooling fluid passage conduits communicate with each other. [Fig.1 A] represents a schematic axial sectional view of a hydrogen aeronautical turbomachine according to a first embodiment of the invention. [Fig.1B] represents a schematic axial sectional view of a hydrogen aeronautical turbomachine according to a second embodiment of the invention. [Fig.1C] represents a schematic axial sectional view of a hydrogen aeronautical turbomachine according to a third embodiment of the invention. [Fig.1D] represents a schematic axial sectional view of a hydrogen aeronautical turbomachine according to a fourth embodiment of the invention. [Fig.2A] represents a schematic perspective view of a heat exchanger of an aeronautical turbomachine according to the first embodiment of the invention. [Fig.2B] represents a schematic cross-sectional view of a heat exchanger of an aeronautical turbomachine according to the first embodiment of the invention. [Fig.3A] represents a schematic perspective view in axial section of a heat exchanger of an aeronautical turbomachine according to the first embodiment of the invention. [Fig.3B] represents a schematic view of a fluid pipe circuit of a heat exchanger of an aeronautical turbomachine according to an embodiment of the invention. [Fig.4A] represents a schematic axial sectional view of a part of a recovery edge of a heat exchanger of an aeronautical turbomachine according to an embodiment of the invention. [Fig.4B] represents a schematic cross-sectional view along the broken lines of [Fig.4A] of a portion of a recovery edge of a heat exchanger of an aeronautical turbomachine according to an embodiment of the invention of [Fig.4A]. [Fig.5SA] represents a schematic view of a fluid pipe circuit of a water collector of an aeronautical turbomachine according to an embodiment of the invention. [Fig.5B] represents a schematic view of a fluid pipe circuit of a water collector of an aeronautical turbomachine according to an embodiment of the invention. [Fig.5C] represents a schematic view of a fluid pipe circuit of a water collector of an aeronautical turbomachine according to an embodiment of the invention. [Fig.6] represents a schematic cross-sectional view of an aeronautical turbomachine exchanger according to an embodiment of the invention. [Fig.7] represents a schematic cross-sectional view of an aeronautical turbomachine exchanger according to an embodiment of the invention. In Figures 1A, 1B, 1C, 1D, the aeronautical turbomachine 100 has dihydrogen as fuel, which is combusted with compressed air from the primary flow FP in a combustion chamber 160. The hydrogen can be stored in the liquid state in one or more hydrogen tanks on the aircraft carrying the turbomachine 100. The aircraft can be for example an airplane or a helicopter and can comprise one or more aeronautical turbomachines 100 intended to propel it into the air. Of course, the aeronautical turbomachine 100 could have below as fuel a fuel stored cryogenically, which is other than dihydrogen. The gas turbine engine assembly or turbomachine 100 extends around an axis AX or axial direction AX (or first longitudinal direction AX mentioned below) oriented from upstream to downstream. Subsequently, the terms “upstream” and “downstream” respectively are taken along the general direction of the gases flowing in the turbomachine along the axis AX. The direction from the inside to the outside is the radial direction DR (or third height direction DR mentioned below) starting from the axis AX. The turbomachine 100 is for example a double-spool turbomachine, as described below. However, in other embodiments not shown, the turbomachine could be a single-spool or triple-spool turbomachine. The invention is particularly interesting for a double-spool turbomachine. Generally speaking, the term low-pressure turbine TBP below can be replaced by turbine. The turbomachine 100 comprises a first stage formed by a rotary fan 28 and a central gas turbine engine 130, located downstream of the rotary fan 28. The central gas turbine engine 130 comprises, from upstream to downstream in the gas flow direction, a low-pressure compressor CBP, a high-pressure compressor CHP, the combustion chamber 160, a high-pressure turbine THP and a low-pressure turbine TBP, which delimit a primary gas flow FP. The rotary fan 28 comprises a set of rotating fan blades 2 extending radially outward from a rotating fan hub 250. The turbomachine 100 has an upstream intake end 290 located upstream of the fan 28, and a downstream exhaust end 370 or nozzle 370 for ejecting the secondary flow. The turbomachine 100 also comprises an inter-vein casing 360 which delimits a primary vein in which circulates the primary flow FP which passes downstream of the fan 28 successively through the low pressure compressor CBP, the high pressure compressor CHP, the high pressure turbine THP and the low pressure turbine TBP. The inter-vein casing 360 comprises, from upstream to downstream, a casing 361 of the low pressure compressor CBP, an intermediate casing 260, which is interposed between the low pressure compressor CBP and the high pressure compressor CHP, a casing 362 of the high pressure compressor CHP, a casing 363 of the high pressure turbine THP and a casing 190 of the low pressure turbine TBP. The low pressure compressor CBP and the high pressure compressor CHP can each have one or more stages, each stage being formed by a set of fixed blades (or stator blades) and a set of rotating blades (or rotor blades). The fixed blades, not shown, of the low pressure compressor CBP are fixed to the casing 361. The rotary blades 120 of the low pressure compressor CBP are fixed to a first rotary transmission shaft, not shown. The fixed blades, not shown, of the high pressure compressor CHP are attached to the casing 362. The rotating blades 104 of the high pressure compressor CHP are attached to a second rotating transmission shaft, not shown. The high pressure turbine THP and the low pressure turbine TBP can each comprise one or more stages, each stage being formed by a set of fixed blades (or stator blades) and a set of rotating blades (or rotor blades). The fixed blades, not shown, of the high pressure turbine THP are fixed to the casing 363. The rotating blades 106 of the high pressure turbine THP are fixed to the second rotating transmission shaft. The fixed blades, not shown, of the low pressure turbine TBP are fixed to the casing 190. The rotating blades 108 of the low pressure turbine TBP are fixed to the first rotating transmission shaft. In operation, air flows through the rotary fan 28 and a first portion FP (primary flow FP) of the air flow is routed through the low-pressure compressor CBP and the high-pressure compressor CHP, in which the air flow is compressed and sent to the combustion chamber 160. The hot combustion products (exhaust gases, not shown in the figures) from the combustion chamber 160 are used to drive the turbines THP and TBP and thus produce the thrust of the turbomachine 100. The exhaust gases produced by the combustion of hydrogen in the combustion chamber 160 of the turbomachine 100 contain water vapor and are sent in the primary flow FP successively downstream in the blades 106 of the high-pressure turbine THP, then in the blades 108 of the low pressure turbine TBP. The rotating blades 108 of the low pressure turbine TBP drive the rotating blades 120 of the low pressure compressor CBP to rotate about the axis AX under the effect of the thrust of the combustion gases coming from the combustion chamber 160. The rotating blades 106 of the high pressure turbine THP drive the rotating blades 104 of the high pressure compressor CHP to rotate about the axis AX under the effect of the thrust of the combustion gases coming from the combustion chamber 160. The turbomachine 100 also includes a secondary vein 390 which is used to pass a secondary flow FS of the air flow discharged from the rotary fan 28 around the inter-vein casing 360. More specifically, the secondary vein 390 extends between an inner wall 350 of a fairing 300 or nacelle 300 and the inter-vein casing 360 surrounding the central gas turbine engine 130. Arms not shown connect the intermediate casing 260 to the inner wall 350 of the fairing 300 in the secondary vein 390 of the secondary flow FS. The low-pressure turbine TBP comprises in its downstream part along the direction AX a rear casing 101 delimiting an annular duct 102 for the outlet of the exhaust gases G from the turbomachine 100, containing water vapor resulting from the combustion of hydrogen in the combustion chamber 160. The rear casing 101 is connected downstream to the gas ejection nozzle 370. The rear casing 101 comprises an annular outer wall 1012 and an annular inner wall 1011, connected to the annular outer wall 1012 by arms (not shown and which may be substantially radial). The annular outer wall 1012, the annular inner wall 1011 and the arms of the rear casing 101 delimit between them the annular duct 102 for the outlet of the exhaust gases G.Between the annular inner wall 1011 and the rotating blades 106 of the high-pressure turbine THP there is also another annular duct 103 for the exhaust gases G, which also communicates with the annular duct 102 for the exhaust gases G. The annular inner wall 1011 internally delimits the other annular duct 103 for the exhaust gases G. The turbomachine 100 comprises a heat exchanger 200a or 200b or 200c or 2004, located downstream of the low pressure turbine TBP and upstream of the primary flow ejection nozzle 370. Below, the heat exchanger 200a or 200b or 200c or 200d of the aeronautical turbomachine 100 according to the invention is described in different embodiments with reference to FIGS. 1A, 1B, 1C, 1D, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 5C, 6 and 7. In the embodiments shown as examples in Figures 1A, 1B, 1C, 1D, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 5C, 6 and 7, the heat exchanger 200a or 200b or 200c or 200d comprises a hollow wall 202 or several hollow walls 201, 202, 203. The interior 302 (or 301, 302, 303; 302) of the hollow wall 202 or the hollow walls 201, 202, 203 is delimited by one (or several) first surface 206 thereof and delimits a first conduit 302 for the passage of a cooling fluid R or several conduits 301, 302, 303 for the passage of a cooling fluid R. The hollow wall 202 or the hollow walls 201, 202, 203 adjoins by one (or more) second surface 205 for condensation of the liquid water a space 204, which is separated from the interior 302 (or 301, 302, 303; 302) of the hollow wall 202 or the hollow walls 201, 202, 203.The interior 302 (or 301, 302, 303; 302) of the hollow wall 202 or of the hollow walls 201, 202, 203 is delimited by the second surface(s) 205 for condensation of the liquid water and is in contact with the exhaust gas G of the turbomachine. The second surface(s) 205 of the heat exchanger 200a or 200b or 200c or 200d comprises one (or more) downstream edge 304 for recovering the liquid water W condensed on the second surface(s) 205. The heat exchanger 200a or 200b or 200c or 200d comprises a gravity liquid water collector 305, which is connected to the downstream edge 304 (or downstream edges 304) and which is positioned below it. The downstream recovery edge(s) 304 and the collector 305 are configured to collect the liquid and condensed water W, present on the second condensation surface(s) 205. The liquid water collector 305 can collect the liquid water by gravity with entrainment / forcing by extraction of a fraction of the exhaust gases. Thus, the cooling fluid R makes it possible to cool the hollow wall 202 or the hollow walls 201, 202, 203 and causes the condensation of the water W of the exhaust gas flow G against the second surface(s) 205. The outer surface(s) 205 therefore forms a surface condenser of liquid water, incorporated into the heat exchanger 200a or 200b or 200c or 200d. The second surface(s) 205 is therefore one (or more) second water condensation surface 205. Thus, the exhaust gas flow G at the outlet of the heat exchanger 200a or 200b or 200c or 200d contains less water. The condensed water W in the liquid state on the second surface(s) 205 of the heat exchanger 200a or 200b or 200c or 200d flows towards the downstream edge(s) 304, being pushed by the exhaust gas flow G passing in the space 204 from upstream to downstream. In a first embodiment, shown by way of example in Figures 1A, 2A, 2B and 3A, the heat exchanger 200a comprises an inner wall 201 surrounding the axis AX, an outer wall 202 surrounding the inner wall 201 around the axis AX and connecting walls 203 fixed between the inner wall 201 and the outer wall 202. The inner wall 201 may for example be circular cylindrical around the axis AX. outer wall 202 may for example be circular cylindrical around the axis AX. The connecting walls 203 may be substantially radial. Of course, the inner wall 201, the outer wall 202 and the connecting walls 203 could have another shape. In this first embodiment, the inner wall 201, the outer wall 202 and the connecting walls 203 are integrated into the rear casing 101. For example, the inner wall 201 can be integrated into the annular inner wall 1011 of the rear casing 101. For example, the outer wall 202 can be integrated into the annular outer wall 1012 of the rear casing 101. The inner wall 201, the outer wall 202 and the connecting walls 203 are hollow. In this first embodiment, the term "inner" means inside the hollow walls 201, 202, 203, that is to say qualifies the inner surfaces 206, which delimit the hollows in the hollow walls 201, 202, 203. The inner wall 201, the outer wall 202 and the connecting walls 203 have the first inner surfaces 206, which delimit the first conduit 301 for the passage of a cooling fluid R located in the inner wall 201, the second conduit 302 for the passage of the cooling fluid R located in the outer wall 202 and the third conduits 303 for the passage of the cooling fluid R located in the connecting walls 203.The conduits 301, 302 and 303 communicate with each other. Of course, only one or more third conduits 303 may be provided in one or more of the walls 203 without the other conduits 301 and / or 302, in the case where only the connecting wall(s) 203 is hollow. Of course, only the first conduit 301 may be provided for passage in all or part of the internal wall 201 without the other conduits 302 and / or 303 in the case where only the internal wall(s) 201 is hollow. Of course, only the second conduit 302 may be provided for passage in all or part of the external wall 202 without the other conduits 301 and / or 303 in the case where only the external wall(s) 202 is hollow. Of course, the conduits 301, 302 and 303 may not communicate with each other. The inner wall 201, the outer wall 202 and the connecting walls 203 have the second surfaces 205 for condensation of the liquid water, which are exposed to the flow of the exhaust gases G. The second surfaces 205 of the inner wall 201, the outer wall 202 and the connecting walls 203 delimit sectors 204, in which the flow of the exhaust gases G passes in the axial direction AX from upstream to downstream. The sectors 204 for the passage of the exhaust gases G are located in the annular exhaust gas outlet duct 102 downstream of the latter. The second surfaces 205 of the connecting walls 203 are located on the opposite side (i.e. separated by the material of the connecting walls 203) relative to the first interior surfaces 206 of the connecting walls 203. The second surfaces 205 of the inner wall 201 are located on the opposite side (i.e. separated by the material of the inner wall 201) relative to some of the first inner surfaces 206 of the inner wall 201 (i.e. relative to those of the first inner surfaces 206 of the inner wall 201 which are located around the first conduit 301 for the passage of the cooling fluid R). The second surfaces 205 of the outer wall 202 are located on the opposite side (i.e. separated by the material of the outer wall 202) relative to some of the first inner surfaces 206 of the outer wall 202 (i.e. relative to those of the first inner surfaces 206 of the outer wall 202 which are surrounded by the second conduit 302 for the passage of the cooling fluid R). In a second embodiment, shown as an example in FIGS. 1B, 6 and 7, the heat exchanger 200b has its hollow wall 202 located downstream of the rear casing 101. The space 204 is located downstream of the other annular exhaust gas outlet conduit 103. The second surface 205 for condensation of the liquid water is located on an inner side 2021 of the hollow wall 202, this inner side 2021 of the hollow wall 202 being surrounded by the interior 302 of the hollow wall 202. The space 204 for passage of the exhaust gases G is therefore surrounded by the hollow wall 202 and by the first conduit 302 for passage of the cooling fluid R. The outer side 2022 of the hollow wall 202 surrounds the first conduit 302 for passage of the cooling fluid R, the inner side 2021 of the hollow wall 202 and the space 204 for passage of the exhaust gases G. The inner side 2021 of the hollow wall 202 is fixed to the annular inner wall 1011 of the rear casing 101. Thus, the space 204 for the passage of the exhaust gases G is downstream of the other exhaust gas outlet duct 103 surrounded by the annular inner wall 1011 of the rear casing 101. In a third embodiment, shown as an example in FIGS. 1C, 6 and 7, the heat exchanger 200c has its hollow wall 202 located downstream of the rear casing 101. The space 204 is located downstream of the annular exhaust gas outlet conduit 102. The second surface 205 for condensation of the liquid water is located on an inner side 2021 of the hollow wall 202, this inner side 2021 of the hollow wall 202 being surrounded by the interior 302 of the hollow wall 202. The space 204 for passage of the exhaust gases G is therefore surrounded by the hollow wall 202 and by the first conduit 302 for passage of the cooling fluid R. The outer side 2022 of the hollow wall 202 surrounds the first conduit 302 for passage of the cooling fluid R, the inner side 2021 of the hollow wall 202 and the space 204 for passage of the exhaust gases G. One (or more) inlets 2023 are provided in the inner side 2021 of the hollow wall 202 to bring the exhaust gases G into the space 204. One (or more) outlets 2024 are provided in the outer side 2022 of the hollow wall 202 to bring the exhaust gases G out. The outlet 2024 is located further downstream than the inlet 2023. The flow of exhaust gases G entering the exchanger 200c is thus returned to the secondary flow of the turbine. In a fourth embodiment, shown as an example in Figures 1D, 6 and 7, the heat exchanger 200d has its hollow wall 202 located downstream of the rear casing 101. The space 204 is located downstream of the annular exhaust gas outlet duct 102. The second surface 205 for condensation of the liquid water is located on an inner side 2021 of the hollow wall 202, this inner side 2021 of the hollow wall 202 being surrounded by the interior 302 of the hollow wall 202. The space 204 for passage of the exhaust gases G is therefore surrounded by the hollow wall 202 and by the first conduit 302 for passage of the cooling fluid R. The outer side 2022 of the hollow wall 202 surrounds the first conduit 302 for passage of the cooling fluid R, the inner side 2021 of the hollow wall 202 and the space 204 for passage of the exhaust gases G. One (or more) inlets 2023 are provided in the inner side 2021 of the hollow wall 202 to bring the exhaust gases G into the space 204. One (or more) outlets 2024 are provided in the outer side 2022 of the hollow wall 202 to bring the exhaust gases G out. The outlet 2024 is located further downstream than the inlet 2023. One (or more) outlets 2024 are provided in the inner side 2021 of the hollow wall 202 to bring the exhaust gases G out. The flow of exhaust gases G passing through the exchanger 200d is thus reinjected into the primary flow of the turbine. According to one embodiment of the invention, the turbomachine comprises a source of cryogenic liquid providing the cooling fluid R in the form of a cryogenic liquid. According to one embodiment of the invention, the cooling fluid R may be liquid hydrogen from the hydrogen tank. Thus, the hydrogen from the tank may be heated by the first surface(s) 206 of the heat exchanger 200a or 200b or 200c or 200d, in order to be able to convert this hydrogen to the gaseous state and then be able to inject it in this gaseous state into the combustion chamber 160, in order to burn it there. In other embodiments of the invention, the cooling fluid R is other than the liquid hydrogen of the hydrogen tank. The cooling fluid R may be, for example, nitrogen, carbon dioxide, or others. Cooling fluids R may also be available as part of the implementation of a heat transfer loop intended to reheat and / or vaporize the hydrogen before its introduction into the combustion chamber 160. The exchanger 200a or 200b or 200c or 200d may be supplied by a fixed flow rate of cooling fluid R, a passive variable flow rate of cooling fluid R, for example if this flow rate is driven by a component connected to one of the rotors of the engine 130, or an active variable flow rate of cooling fluid R, if this flow rate is for example driven by a motor pump separate from the rotors of the engine 130. The condenser part formed by the second surfaces 205 may represent all or part of the exchanger 200a or 200b or 200c or 2004, and the part of the exchanger 200a or 200b or 200c or 200d used to condense the water vapor may be variable and controlled: either by temporarily supplying a part of the internal wall 201 and / or the external wall 202 and / or walls 203 connecting with the cooling fluid R dissement, either by controlling a 207 exhaust gas valve G presented in the [Fig.3B], which will allow or not the entrainment of condensed water towards the 305 water collector. The general shape of the exchanger 200a or 200b or 200c or 200d may be, for example, a turbine casing shape. Another shape may be given to this exchanger / condenser 200a or 200b or 200c or 200d in order to improve the water yield (for example by adding arms, an extension, the addition of baffles intended to maximize the exhaust gas / cold surface contacts). According to an embodiment of the invention, shown as an example in Figures 4A and 4B, the downstream recovery edge 304 comprises a network of downstream channels or gutters 306, 307, 308 converging towards the liquid water collector 305 W. This forms a system for capturing the recovered liquid water. The positioning of the gutters 306, 307, 308 downstream of the heat exchanger 200a or 200b or 200c or 200d has the dual advantage of leaving a maximum condensation surface available, and the possibility of limiting the pressure losses seen by the exhaust gases G, which can have a significant impact on the performance of the machine and therefore on the formation of condensation trails. This network of gutters 306, 307, 308 can be produced in several ways: mechanically welded, or by additive manufacturing. According to one embodiment of the invention, the downstream recovery edge 304 comprises on the downstream part of the internal wall 201 or on the internal side 2021 at least one internal gutter 307 for the flow of liquid water. According to one embodiment of the invention, the downstream recovery edge 304 comprises on the downstream part of the external wall 202 or on the internal side 2021 at least an external 308 gutter for the flow of liquid water. According to one embodiment of the invention, the downstream recovery edge 304 comprises on the downstream part of each connecting wall 203 at least one radial gutter 306 for the flow of liquid water. According to one embodiment of the invention, the two second condensation surfaces 205 of the same connecting wall 203 are connected to each other by an intermediate surface 308 delimiting upstream the radial gutter 306 for the flow of liquid water. An upstream spout 307 makes an acute angle between each second condensation surface 205 of the connecting wall 203 and one side of the intermediate surface 308 and also delimits upstream the radial gutter 306 for the flow of liquid water. A downstream surface 309 of the gutter bottom or chute 309 is arranged at a distance and downstream of the intermediate surface 308 and the upstream spouts 307. The downstream surface 309 of the gutter bottom delimits downstream the radial gutter 306 for the flow of liquid water. The spacing of the chute 309 relative to the two second surfaces 205 and the intermediate surface 308 allows the liquid water flowing over the wall 203 to pass through.The water is driven into the radial gutter 306 towards the collector 305 by gravity. The upstream spout 307 ensures, upstream, an angle break allowing the formation of water drops. These water drops are driven into the capture system 306, 307, 308. According to one embodiment of the invention, this training can be continuous. According to one embodiment of the invention, this training can be carried out upon activation of the ambient air valve 207 shown in |Fig.3B]. The pressure differential between the internal part of the nozzle 370 and the ambient air (or the secondary flow FS) is used. According to one embodiment of the invention, the downstream surface 309 of the gutter bottom is connected by its upstream ends 3092 to an upstream non-return rim 3091 directed inwards and positioned upstream and at a distance from the downstream surface 309 of the gutter bottom. This upstream non-return rim 3091 adjoins the opening 310. This upstream non-return rim 3091 makes it possible to trap the drops W of water against the downstream surface 309 of the gutter bottom and to prevent overflow, as indicated by the arrow F in [Fig.4B]. According to an embodiment of the invention, as shown in [Fig.2A] and 4B, each connecting wall 203 is profiled with an aerodynamic shape tapering from upstream to downstream from an intermediate portion 2030 having a maximum transverse width L3 along the transverse direction E (or circumferential around the axial direction AX) perpendicular to the direction AX and to the radial direction DR. The two second surfaces 205, opposite each other, of the connecting wall 203 approach each other along the transverse direction E, when goes from the intermediate portion 2030 to the downstream edge 304 in the axial direction AX. The chute 309 has a transverse width L2, which is smaller than the transverse width L1 of the intermediate surface 308 in the transverse direction E (between the upstream spouts 307) and which, opposite the intermediate surface 308 in the axial direction AX, The downstream surface 3090 of the chute 309 may be formed by a rounded trailing edge of the connecting wall 203. According to one embodiment of the invention, an external radial opening 310 for sampling a portion of the exhaust gases in the radial gutter 306 for the flow of liquid water W is arranged between the upstream nozzles 307 and the downstream surface 309 of the gutter bottom. Thus, the water is driven in the radial gutter 306 towards the collector 305 by gravity, but also by the establishment of a drive circuit based on the extraction of a portion of the exhaust gases through the opening 310, these exhaust gases pushing the water into the opening 310. This drive circuit uses the pressure differential between the interior of the nozzle 370 of the turbomachine and the ambient air. The external radial opening 310 may be present in the aerodynamic shape tapering from upstream to downstream of the connecting wall 203. According to one embodiment of the invention, the external gutter 308 for the flow of liquid water is in the form of a groove on the external wall 201. According to one embodiment of the invention, the internal gutter 307 for the flow of liquid water is in the form of a groove on the internal wall 202. Upon arrival in the liquid water collector 305, the water flows by gravity, and the exhaust gases G continue their journey towards the nozzle 370 located on the external part of the nacelle (towards the ambient or towards the secondary flow FS). A regulation valve 207 or cut-off valve 207 may be installed upstream of the sectors 204 of passage of the exhaust gases G, so as to activate or regulate the flow of exhaust gas G, and consequently the capture of water in the collector 305. The water extraction network 306, 307, 308 can follow a route similar to that of the network of conduits 301, 302, 303 of cold cooling fluid R, with one partition, and for example in the opposite direction, so as to continue the liquefaction of the water vapor of the exhaust gases G used for the drive. Furthermore, the drop in temperature of the exhaust gases G can be used to lower the pressure downstream and thus increase the efficiency of the drive. Air taps and the water collector 305 can be positioned to prevent any icing of the capture system during engine use. Drains can be provided to prevent water stagnation when the engine is stopped to avoid any icing of the water when the engine is not running. An additional exhaust gas tap from the nozzle 370 can be used to defrost the system. when starting or restarting the engine. The total volume of water captured, even with 50% performance of the capture system, can exceed the order of magnitude of a ton over the duration of a flight of a few hours. There are several possibilities for using the liquid water W collected in the collector 305. These different possibilities of use can be combined. According to a first possibility, part of the liquid water collected in the collector 305 is sent to the aircraft, via a network of pumps, filters, and control valves, for example to supply its non-potable water network. According to a second possibility, a portion of the liquid water W collected in the collector 305 is used to perform in-flight engine washes. The liquid water collected in the collector 305 can be immediately reinjected into the high-pressure compressor CHP with the resulting savings on the mass of the collector 305. According to a third possibility, part of the liquid water collected in the collector 305 is used in a water-methanol mixture to increase the power of engines which use this technique. According to a fourth possibility, part of the liquid water collected in the collector 305 is injected into the combustion chamber 160. This helps to reduce NOx in it. Indeed, the production of NOx is one of the major drawbacks of using hydrogen as fuel, because the temperature at the heart of the flame is very high. The injection of water, moderate in vapor upstream of the flame and in greater quantity in the dilution, makes it possible to lower the flame temperature which directly controls the production of NOx and to freeze the slow reactions including NOx downstream of the flame. The reduction in temperatures, particularly at the outlet of the chamber 160, also makes it possible to operate at higher richness (therefore more energy available) without affecting the service life of the turbine (and the chamber). However, it may be necessary (depending on the intended uses) to release a certain proportion of the liquid water collected in the collector 305, either instantly, or at regular intervals, or upon leaving the conditions of condensation trail formation (depending on the altitude / temperature / relative humidity conditions, defined for example by Schmidt-Appleman in the scientific literature). It is possible to release the water continuously, but in a form that does not generate condensation trails (calibrated drops for example, which can precipitate quickly instead of remaining at altitude). This captured water W can be used for temporary storage on the aircraft and its release into the atmosphere in a controlled form (drop size), allowing for example, faster precipitation of water and thus a limitation of the formation of condensation trails having a significant impact on radiative forcing. According to an embodiment of the invention, shown in Figures 3B and 5B, the turbomachine 100 comprises a device 431 for automatic calibration of a predefined volume 412 of liquid water W output from the collector 305. This automatic calibration device 431 may be passive and comprise a float 432 triggering the opening of a valve 433 provided on a water outlet pipe 434 connected to the collector 305 (passive system). This predefined volume 412 of water is sent by the pipe 434 to another water release outlet 435 located on the nacelle 300, near or not to the nozzle 370 for discharging the exhaust gases from the sampling system. The water release outlet 435 may be located at a low point of the nacelle 300, preferably towards the ambient air, but possibly towards the secondary flow FS of the turbomachine 100.The shape of this water release outlet 435 can be configured to calibrate the water drops released into the atmosphere. For example, the aerodynamic shear forces of the ambient air, or of the exhaust gases from the water capture system, can be used to control the size of the water drops emitted (passive system). The turbomachine 100 may comprise a device 400 for calibrating the size of the water droplets W ejected outwards from the collector 305. Examples of devices 400 for calibrating the size of the water droplets ejected outwards from the collector 305 are given below. This device 400 for calibrating the size of the water droplets ejected outwards from the collector 305 may aim to maximize the size of the water droplets, to cause rapid precipitation of the water, before the formation of condensation trails and to control the size of the emitted water droplets, in a size range demonstrated to generate less condensation trails. It may be possible to envisage modifying the operating mode of the device 400 for calibrating the size of the water droplets ejected outwards from the collector 305 depending on the flight phases or meteorological conditions. According to an embodiment of the device 400 for calibrating the size of the water drops ejected outwards from the collector 305, shown in [Fig.5A], the liquid water collector 305 is connected to a system 401 for pneumatically pressurizing the water to eject the water contained in the collector 305 by ejection nozzles 402 in the form of pressurized droplets outwards. This pressurized nozzle type solution makes it possible to finely control the size of the emitted water drops. Another alternative could use an active system of pressurized nozzles, making it possible to achieve a more precise distribution of drop sizes (by controlling the speed of shear). According to an embodiment of the device 400 for calibrating the size of the water drops ejected outwardly from the collector 305, shown in [Fig. SB], the liquid water collector 305 is connected to a flushing device 411, configured to release a predefined volume 412 of water outwardly when the liquid water reaches this determined volume 412 in the liquid water collector 305, as represented by the graph of the volume V of water present in the collector 305 as a function of time t in [Fig. 5B]. This makes it possible to limit the shear forces as much as possible to maximize the size and therefore the precipitation of the water drops outwardly. According to an embodiment of the device 400 for calibrating the size of the water drops ejected outwards from the collector 305, shown in [Fig.5C], the liquid water collector 305 is connected to nozzles 421 for continuously discharging the water from the collector 305 outwards. This gravity solution is simple. The water is continuously discharged there. The shape of the nozzles 421 as well as the ambient air directly determine the size profile of the emitted water drops. According to one embodiment of the invention, the turbomachine 100 comprises a device 500 for defrosting the water W coming from the collector 305 and the water stored in the collector 305. In order to avoid excessively rapid icing of the discharged water drops and / or to avoid icing of the device 400 for calibrating the size of the water drops ejected outwards from the collector 305, a hot gas GC may be used for entraining the water drops coming from the collector 305. This hot gas GC for entraining the water drops may be, for example, hot air taken, for example, from the high-pressure compressor CHP or the low-pressure compressor CBP of the engine 130. Or this hot gas GC for entraining the water drops may be, for example, a portion of the flow of exhaust gases G taken at the appropriate axial position in terms of temperature, coming from the combustion chamber 160.Or this hot GC gas for entraining water drops can be, for example, more simply the ventilation / cooling air from a compartment which has been heated by the equipment in the area and which is then discharged to the ambient air to ensure good circulation. Coupling with a source of hot air or combustion gases makes it possible to make the system functional at low temperature, and to delay, if necessary, the crystallization of the water. Concerning the control mode of the heat exchanger 200a or 200b or 200c or 200d, several solutions, described below, can be considered. A first mode of control of the heat exchanger 200a or 200b or 200c or 200d is passive. The sizing of the heat exchanger 200a or 200b or 200c or 200d is sufficient for its proper operation and it operates continuously, at variable performance levels (depending for example on the power taken for the heating of hydrogen, or the pressure difference between the inside and outside of the engine). A second control mode for the heat exchanger 200a or 200b or 200c or 200d is active. The second mode of control of the heat exchanger 200a or 200b or 200c or 200d may only control the flow of air or drive gas G via one or more valves 207 in [Fig.3B]. Or the second mode of control of the heat exchanger 200a or 200b or 200c or 200d can only control the flow rate of cooling fluid R in the exchanger 200a or 200b or 200c or 200d to vary the captured thermal power and therefore the condensation of the water. This option is however limiting if a target temperature and flow rate of hydrogen must be reached at injection into the combustion chamber 160. Or the second mode of control of the heat exchanger 200a or 200b or 200c or 200d can control the flow of air or gas G taken according to the flow conditions of the cooling fluid R in the exchanger 200a or 200b or 200c or 200d. The activation of the heat exchanger 200a or 200b or 200c or 200d and the elements described above can be carried out according to a logic based on measurements of altitude, ambient temperature and pressure, relative humidity, flow rate of burned fuel, temperature of the combustion products. It may be envisaged to limit the activation of the heat exchanger 200a or 200b or 200c or 200d to the occurrence of conditions conducive to the formation of condensation trails (Schmidt-Appleman criteria for example). The device 400 for calibrating the size of the water drops and / or the device 431 for automatically calibrating a predefined volume 412 of liquid water make it possible to release in a controlled manner a portion of the water generated by the combustion chamber 160. The heat exchanger 200a or 200b or 200c or 200d, the water collector 305, the device 400 for calibrating the size of the water drops and / or the device 431 for automatically calibrating a predefined volume 412 of liquid water make it possible to control a portion of the generation of condensation trails by aircraft engines, using dihydrogen as the main fuel. Of course, the embodiments, features, possibilities and examples described above can be combined with one another or selected independently of one another.

Claims

Claims

1. Aeronautical turbomachine (100) powered by hydrogen or other fuel stored cryogenically, comprising a turbine (TBP), comprising a casing (101) delimiting a conduit annular (102, 103) of exhaust gas outlet (G) of the tur- bomachine (100), containing water vapor, a heat exchanger (200a, 200b, 200c, 200d), located downstream of the turbine (TBP), characterized in that the heat exchanger (200a, 200b, 200c, 200d) comprises at least one hollow wall (201, 202, 203; 202) whose interior (301, 302, 303; 302) delimited by at least a first surface (206) of the hollow wall (201, 202, 203; 202) delimits a first conduit (301, 302, 303; 302) passage of a cooling fluid (R), the hollow wall (201, 202, 203; 202) adjoining by a second surface (205) of condensation of liquid water a space (204), which is separated from the interior (301, 302, 303; 302) of the hollow wall (201, 202, 203), which is delimited by the second surface (205) of condensation of the water liquid and which is in contact with the exhaust gas (G) of the tur- bomachine, the second surface (205) of condensation of liquid water belonging to the hollow wall (201, 202, 203; 202) and being distinct from the first surface (206), the second condensation surface (205) of the exchanger (200a, 200b, 200c, 200d) of heat comprising at least one downstream edge (304) of recov- operation of liquid water, the heat exchanger (200a, 200b, 200c, 200d) comprising a liquid water collector (305) by gravity, which is connected to the downstream edge (304) recovery under it, the downstream edge (304) of recovery and the collector (305) of liquid water being configured to collect liquid and condensed water, present on the second condensation surface (205).

2. Turbomachine according to claim 1, characterized in that the heat exchanger (200a) comprises an internal wall (201), a outer wall (202) surrounding the inner wall (201) and walls (203) connecting elements fixed between the inner wall (201) and the outer wall (202), the inner wall (201) and / or the outer wall (202) and / or the walls (203) connecting surfaces being hollow and having said first surfaces (206) de- respectively limiting a first conduit (301) for the passage of a fluid cooling and / or a second conduit (302) for the passage of a cooling fluid and / or third passage conduits (303) of a cooling fluid, the inner wall (201), the outer wall (202) and the walls (203) of connection being integrated into the rear casing (101) and having said second surfaces (205) of condensation of liquid water, delimiting sectors (204) of passage of passage of the exhaust gases (G), which are located in the annular exhaust gas (G) outlet duct (102).

3. Turbomachine according to claim 1, characterized in that the rear casing (101) has an annular inner wall (1011) de- internally limiting the annular duct (103) for the gas outlet (G) exhaust, the hollow wall (202) of the exchanger (200b) is located downstream of the casing rear (101), the space (204) being located downstream of the annular outlet conduit (103) of exhaust gas (G).

4. Turbomachine according to claim 1, characterized in that the rear casing (101) comprises an annular outer wall (1012) and an annular inner wall (1011), which delimit between them the annular duct (102) for the exhaust gas (G) outlet, the hollow wall (202) of the exchanger (200c, 200d) is located downstream of the rear casing (101), the space (204) being located downstream of the annular outlet conduit (102) of exhaust gas (G).

5. Turbomachine according to claim 4, characterized in that the second surface (205) of condensation of liquid water is located on an internal side (2021) of the hollow wall (202) of the exchanger (200c), this inner side (2021) of the hollow wall (202) being surrounded by the interior (302) of the hollow wall (202), the space (204) for the passage of gases (G) exhaust being surrounded by the hollow wall (202) and by the first conduit (302) for passage of the cooling fluid (R), an external side (2022) of the hollow wall (202) surrounding the first conduit (302) for the passage of the cooling fluid (R), the side internal (2021) of the hollow wall (202) and the space (204) for the passage of the exhaust gas (G), at least one entrance (2023) is provided in the internal side (2021) of the hollow wall (202) for letting the exhaust gases (G) into space (204), at least one exit (2024) is provided in the external side (2022) of the hollow wall (202) for letting the exhaust gases (G) out, the outlet (2024) being located further downstream than the inlet (2023).

6. Turbomachine according to claim 4, characterized in that the second surface (205) of condensation of liquid water is located on an internal side (2021) of the hollow wall (202) of the exchanger (200d), this inner side (2021) of the hollow wall (202) being surrounded by the interior (302) of the hollow wall (202), the space (204) for the passage of gases (G) exhaust being surrounded by the hollow wall (202) and by the first conduit (302) for passage of the cooling fluid (R), an external side (2022) of the hollow wall (202) surrounding the first conduit (302) for the passage of the cooling fluid (R), the side internal (2021) of the hollow wall (202) and the space (204) for the passage of the exhaust gas (G), at least one entrance (2023) is provided in the internal side (2021) of the hollow wall (202) for letting the exhaust gases (G) into space (204), at least one exit (2024) is planned in the internal side (2021) of the hollow wall (202) for letting the exhaust gases (G) out, the outlet (2024) being located further downstream than the inlet (2023).

7. Turbomachine according to any one of the preceding claims, characterized in that the downstream recovery edge (304) comprises a network of gutters (306, 307, 308) converging to the collector (305) of liquid water.

8. Turbomachine according to any one of claims 2, 5, 6, ca- characterized in that the downstream edge (304) of recovery comprises on the downstream part of the internal wall (201) or of the internal side (2021) at least an internal gutter (307) for the flow of liquid water, the downstream edge (304) of recovery comprises on the downstream part of the wall external (202) or on the external side (2022 at least one gutter (308) external flow of liquid water.

9. Turbomachine according to claim 2, characterized in that the edge downstream (304) recovery comprises on the downstream part of each wall (203) connecting at least one radial flow gutter (306) of liquid water.

10. Turbomachine according to any one of the preceding claims, characterized in that the liquid water collector (305) is connected to a pneumatic water pressurization system (401) for ejecting water contained in the collector (305) by ejection nozzles (402) under a form of droplets under pressure outwards.

11. | Turbomachine according to any one of the preceding claims, characterized in that the liquid water collector (305) is connected to a flushing device (411), configured to release outwardly a determined volume (412) of water when liquid water reaches this volume determined (412) in the liquid water collector (305).

12. Turbomachine according to any one of the preceding claims, characterized in that the liquid water collector (305) is connected to nozzles (421) for continuous evacuation of water from collector (305) towards the outside.

13. Turbomachine according to any one of the preceding claims, characterized in that the turbomachine (100) comprises a re- regulation or cutting of the flow of exhaust gases (G) upstream of the heat exchanger (200a, 200b, 200c, 200d).

14. Turbomachine according to any one of the preceding claims, characterized in that the cooling fluid (R) is hydrogen serving as fuel for the turbomachine (100) or another fuel stored cryogenically as fuel for the tur- bomachine (100) or a heat transfer fluid.