Aircraft turbomachine comprising a heat exchanger in an air stream and its method of use

Abstract

An aircraft turbomachine (1) comprising: - an air stream (4) delimiting a free volume in which an airflow (F) circulates from upstream to downstream; - a volumetric heat exchanger (10) comprising a fluidic network extending in the free volume of the air stream (4) and comprising an internal surface for guiding a fluid to be cooled and an external surface defining passages for the circulation of the airflow (F) to cool the fluid to be cooled, the heat exchanger (10) comprising a height greater than 50% of a height of the air stream (4); - light-emitting diodes (18) in the infrared range fixed on an upstream end (15) of the heat exchanger (10) and electrically controllable in an active mode ensuring de-icing or preventing icing of the upstream end (15) of the heat exchanger (10). Figure from the summary: Figure 1

Description

Title of the invention: Aircraft turbomachine comprising a heat exchanger in an air stream and its method of use. Technical field

[0001] The present invention relates to an aircraft turbomachine comprising a heat exchanger in an air stream and its method of use.

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] This sustained research and development work focuses in particular on new generations of aircraft turbomachines that are less energy-intensive and more efficient.

[0005] An aircraft turbomachine extending along a longitudinal axis and comprising upstream a very large diameter, typically exceeding 3.5 m, unshrouded fan is known in particular from patent application WO2024096879A1. During a thrust phase, the unshrouded fan guides an airflow into an inlet duct leading to a primary duct of the aircraft turbomachine. In the primary duct, the airflow flows from upstream to downstream via one or more compressors, a combustion chamber, and one or more turbines.

[0006] In a known manner, the inlet stream comprises a shrouded fan and is externally delimited by a fan casing from which stator blades project outwards. The stator blades are typically unshrouded and define an open secondary stream allowing to accelerate the airflow to promote thrust. The inlet flow also opens into a tertiary flow, extending externally around the primary flow, and known to those skilled in the art as the "third flow", which contributes to the thrust of the aircraft turbomachine.

[0007] In a known manner, one or more air-oil heat exchangers are mounted in the tertiary runner and use it as a cold source to cool the oil heated after circulating in contact with the aircraft turbomachine equipment to cool and / or lubricate it. Such heat exchangers are typically formed in the wall of the tertiary runner.

[0008] In practice, such heat exchangers, referred to as "surface" heat exchangers, increase the cooling capacity of aircraft turbomachinery, supplementing the oil-fuel heat exchangers installed in the fuel circuit. However, this is insufficient to meet the significant cooling requirements of new generations of aircraft turbomachinery, due in particular to the increasing number of electrical components.

[0009] One solution to this problem would be to increase the size of the heat exchangers in the tertiary channel so that they extend into the internal volume of the tertiary channel where the airflow circulates. However, in icing conditions, ice is likely to form on the surface of such heat exchangers, referred to as "volumetric" heat exchangers, which could obstruct the tertiary channel and undesirably disrupt the operability of the aircraft turbomachine.

[0010] The invention thus aims to promote the cooling of equipment in an aircraft turbomachine without impacting the operability or fuel consumption of the aircraft turbomachine. PRESENTATION OF THE INVENTION

[0011] The invention relates to an aircraft turbomachine extending along a longitudinal axis and comprising: • an air stream comprising an inner casing and an outer casing relative to the longitudinal axis, together defining a free volume in which an airflow circulates from upstream to downstream during a thrust phase of the aircraft turbomachine, • at least one volumetric heat exchanger comprising a fluidic network extending into the free volume of the air stream, the fluidic network comprising an internal surface for guiding a fluid to be cooled and an external surface defining a plurality of airflow passages so as to cool the fluid to be cooled, the volumetric heat exchanger comprising a transverse height relative to the axis longitudinal greater than 50% of a transverse height of the air stream defined between the inner and outer casings,

[0012] The invention is remarkable in that the aircraft turbomachine comprises a plurality of infrared light-emitting diodes fixed on an upstream end of the volumetric heat exchanger and electrically controllable between an inactive mode and an active mode ensuring de-icing or preventing icing of the upstream end of the volumetric heat exchanger.

[0013] The invention advantageously prevents the formation and / or accumulation of frost on the volumetric heat exchanger, which could eventually obstruct the air stream. Thanks to the invention, the airflow within the air stream is maintained under icing conditions. The invention thus offers the possibility of using the entire cross-section of the air stream for cooling purposes, unlike surface heat exchangers of the prior art. This makes it possible, in particular, to meet the increasing cooling requirements of new generations of aircraft turbomachinery incorporating more electrical equipment that needs to be cooled.

[0014] Positioning the LEDs upstream allows for efficient, localized defrosting without significant energy consumption at the upstream end where frost is most likely to form. Furthermore, the LEDs also serve a secondary function: they warm the fluid to be cooled, which could otherwise freeze in the fluid network under certain cold conditions. Advantageously, there is no need for defrosting channels within the internal surface of the heat exchanger, as in the prior art, thus reducing its mass and size. The performance of the heat exchanger is therefore improved.

[0015] According to one aspect of the invention, the transverse height of the volumetric heat exchanger is greater than 80% of the transverse height of the air stream, preferably greater than 90%. The invention advantageously allows the use of large-volume heat exchangers covering all or a predominant part of the stream height to meet significant cooling requirements.

[0016] According to one aspect of the invention, the aircraft turbomachine includes at least one fastening ribbon connecting the light-emitting diodes. This allows the light-emitting diodes to be fixed and controlled in a simple and comprehensive manner.

[0017] According to one aspect of the invention, the aircraft turbomachine comprises a plurality of infrared light-emitting diodes fixed to the external surface of the fluidic network of the volumetric heat exchanger and electrically controllable between an inactive and an active mode. This makes it possible to heat the fluid circulating in the fluidic network under certain cold conditions where it might otherwise freeze. Such This solution avoids the need to include a defrosting system within the fluid network, which is costly and reduces heat exchange under normal conditions.

[0018] According to one aspect of the invention, the aircraft turbomachine comprises a plurality of infrared light-emitting diodes fixed to a downstream end of the volumetric heat exchanger and electrically controllable between inactive and active modes. This contributes to de-icing and prevents the fluid in the fluidic network from freezing.

[0019] According to one aspect of the invention, the volumetric heat exchanger comprises a frame housing the fluidic network and on which are fixed a plurality of electrically controllable infrared light-emitting diodes that can be switched between inactive and active modes. This also contributes to defrosting, particularly at the airflow circulation passages.

[0020] According to one aspect of the invention, the aircraft turbomachine comprises, from upstream to downstream: • an unfaired blower, • an inlet duct supplied with airflow by the unfaired blower, • a primary vein comprising a combustion chamber and a vein tertiary extending around the primary vein, the primary vein and the tertiary vein being supplied with airflow by the inlet vein, the tertiary vein forming the air vein in which the volumetric heat exchanger is mounted.

[0021] The invention is particularly suitable for such aircraft turbomachinery having significant cooling requirements due to the greater number of electrical equipment, in particular the reducer known by the English term "Reduction Gear Box (RGB)".

[0022] According to one aspect of the invention, the tertiary vein comprises a plurality of structural arms extending radially within the free volume relative to the longitudinal axis and upstream of the volumetric heat exchanger. The light-emitting diodes positioned on the upstream end can also be used to defrost the upstream structural arms.

[0023] According to another aspect of the invention, the aircraft turbomachine comprises, from upstream to downstream: • a streamlined blower, • a primary vein comprising a combustion chamber and a ducted secondary vein extending around the primary vein, the primary vein and the ducted secondary vein being supplied with airflow by the ducted blower, the ducted secondary vein forming the air vein in which the volumetric heat exchanger is mounted.

[0024] The invention is also adapted for integration into the secondary flow of a faired aircraft turbomachine.

[0025] The invention also relates to a method of using an aircraft turbomachine as described above, consisting of electrically switching the light-emitting diodes from inactive to active mode so as to de-ice or prevent icing of the upstream end of the volumetric heat exchanger. PRESENTATION OF FIGURES

[0026] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0027] The [Fig.1] is a schematic representation in longitudinal half-section of an aircraft turbomachine according to one embodiment of the invention.

[0028] The [Fig.2] is a schematic representation in longitudinal half-section of a volumetric heat exchanger according to an embodiment of the invention during an active mode of the light-emitting diodes.

[0029] The [Fig.3] is a schematic representation in longitudinal half-section of the volumetric heat exchanger according to an embodiment of the invention during an inactive mode of the light-emitting diodes.

[0030] Fig. 4 is a schematic representation in longitudinal half-section of the volumetric heat exchanger according to another embodiment of the invention.

[0031] The [Fig.5] is a schematic representation in longitudinal half-section of the volumetric heat exchanger according to another embodiment of the invention.

[0032] The [Fig.6] is a schematic representation in longitudinal half-section of an aircraft turbomachine according to another embodiment of the invention.

[0033] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0034] With reference to [Fig. 1], the invention relates to an aircraft turbomachine 1 extending along a longitudinal axis X and comprising an air duct 2, 3, 4. The air duct 2, 3, 4 comprises an inner casing 6 and an outer casing 5 with respect to the longitudinal axis X together delimiting a free volume V in which an airflow F flows from upstream to downstream during a thrust phase of the aircraft turbomachine 1.

[0035] With reference to Figures 1 and 2, the aircraft turbomachine 1 comprises a volumetric heat exchanger 10, known to those skilled in the art as a "matrix exchanger", comprising a fluidic network 11 extending into the free volume V of the air stream 2, 3, 4. The fluidic network 11 includes an internal surface 12 for guiding a fluid to be cooled H, typically oil that has circulated in contact with the equipment of the aircraft turbomachine 1 to cool and lubricate it. The external surface 13 of the fluidic network 11 defines passages 14 for the circulation of the airflow F in order to cool the oil H. The volumetric heat exchanger 10 has a transverse height L10 relative to the longitudinal axis X greater than 50% of the transverse height L of the air stream 2, 3, 4 defined between the inner casing 5 and the outer casing 6.

[0036] According to the invention and with reference to Figures 1 and 2, the aircraft turbomachine 1 comprises infrared light-emitting diodes 18 fixed to an upstream end 15 of the volumetric heat exchanger 10. Also according to the invention, the light-emitting diodes 18 are electrically controllable between an inactive OFF mode ([Fig.3]) and an active ON mode ([Fig.2]) ensuring de-icing or preventing icing of the upstream end 15 of the volumetric heat exchanger 10.

[0037] The invention advantageously prevents the formation and / or accumulation of frost on the volumetric heat exchanger 10, which could obstruct the air stream 2, 3, 4. Thanks to the invention, the circulation of the airflow F in the air stream 2, 3, 4 is maintained under icing conditions, which helps ensure good operating conditions for the aircraft turbomachine 1. The invention allows the entire cross-section of the air stream to be used for cooling purposes, thus meeting the increasing cooling requirements of aircraft turbomachines, which include more and more electrical equipment requiring cooling in addition to rotating components, such as the gearbox 9 connecting the fan 7, 20 to the rotating drive shaft (see [Fig. 1]). The air stream 2, 3, 4 thus advantageously represents a preferred cold source for cooling.

[0038] Furthermore, the light-emitting diodes 18 according to the invention advantageously allow, under cold conditions, the heating of the oil H that could solidify in the fluidic network 11 of the volumetric heat exchanger 10. Advantageously, there is no need to provide defrosting channels inside the internal surface 12 of the heat exchanger 10 as in the prior art, which reduces the mass and size. The performance of the heat exchanger 10 is thus improved.

[0039] With reference to [Fig. 1], the invention relates particularly, but not exclusively, to an aircraft turbomachine 1 comprising a tertiary duct 4 known to those skilled in the art as the "third stream". As will be described later, the tertiary duct 4 forms a passage guiding a portion of the airflow F drawn into the aircraft turbomachine 1 outwards without passing through the primary duct 3, contributing to the thrust of aircraft turbomachine 1. The tertiary vein 4 is distinguished in particular from a secondary vein in that the airflow F is not from outside free air.

[0040] As illustrated in [Fig. 1], the aircraft turbomachine 1 typically includes upstream an unshod fan 7 of very large diameter, typically exceeding 3.5 m, which guides the airflow F into an inlet duct 2 opening on one side into the primary duct 3 and on the other into the tertiary duct 4 of the aircraft turbomachine 1. The inlet duct 2 typically includes a shod fan 20 and is externally delimited by a fan casing 5 from which stator vanes 8 project outwards. The stator vanes 8 are typically unshod and define an open secondary duct fed by the unshod fan 7, which accelerates the airflow F to enhance thrust. In the primary vein 3, the admitted air flow F circulates from upstream to downstream via one or more compressors 21, 22, a combustion chamber 23 and one or more turbines 24, 25.The tertiary vein 4 extends longitudinally externally around the primary vein 3, separated by an interveinal compartment 6, and internally in relation to the secondary vein, separated by the blower housing 5.

[0041] Preferably, and as illustrated in [Fig. 1], the volumetric heat exchanger 10 is mounted in the tertiary flow 4. The volumetric heat exchanger 10 typically extends into the free volume V downstream of structural radial arms 26, preferably at the outlet of the tertiary flow 4 leading to the exterior of the aircraft turbomachine 10. Advantageously, the airflow F circulating in the tertiary flow 4 forms a relatively high-pressure cold source compared to the primary flow 3, ensuring good heat exchange. Furthermore, the pressure losses generated by the volumetric heat exchanger 10, thus positioned, are low and have little impact on the performance of the aircraft turbomachine 1. Installation and maintenance of the volumetric heat exchanger 10 are also straightforward.

[0042] Alternatively, as illustrated in [Fig. 6], the volumetric heat exchanger 10 extends into the secondary flow 28 of a shrouded aircraft turbomachine 1' conventionally comprising a shrouded fan 27 and a primary flow 3 around which the shrouded secondary flow 28 extends. The primary flow 3 and the secondary flow 28 are supplied with airflow F by the shrouded fan 27. Such an architecture is free of an inlet flow 2 and a tertiary flow 4.

[0043] The invention is described below in the case where the volumetric heat exchanger 10 is mounted in the tertiary vein 4 but this description remains valid for another mounting, in particular in the secondary vein 28.

[0044] According to another aspect of the invention, the volumetric heat exchanger 10 extends over a transverse height L10 greater than 80% of the transverse height L of the tertiary stream 4, preferably greater than 90%. In the example shown in Figures 2 and 3, the volumetric heat exchanger 10 extends over the entire height L of the tertiary stream 4 to optimize heat exchange. This is made possible by the integration of the light-emitting diodes 18, which ensure the operability of the aircraft turbomachine 1 in icing conditions.

[0045] In the example shown in Figures 1 to 3, a single volumetric heat exchanger 10 is depicted, but it is understood that there could be several, all or some of which are equipped with light-emitting diodes 18 according to the invention. Preferably, at least the volumetric heat exchanger 10 positioned furthest upstream and most exposed to frost is equipped with light-emitting diodes 18.

[0046] With reference to Figures 2 and 3, the fluidic network 11 of the volumetric heat exchanger 10 typically comprises one or more tubes through which the oil H circulates, the air flow F circulating externally around the tube(s). In this example, the fluidic network 11 comprises a single serpentine tube including one or more bends between straight sections, in this example extending longitudinally with respect to the longitudinal axis X. The straight sections extend alternately transversely with respect to the longitudinal axis X. In the example of [Fig. 5], the fluidic network 11 alternately comprises a bundle of tubes extending longitudinally or transversely with respect to the longitudinal axis X, which are fed by an inlet manifold (not shown) and discharge into an outlet manifold (not shown).

[0047] In the example of Figures 2 and 3, the volumetric heat exchanger 10 comprises a frame 16, also referred to as the "matrix," in which the fluidic network 11 is housed. The airflow F circulates within the frame 16 outside the tubes. The frame 16 comprises one or more walls having openings for the circulation of the airflow F, typically in the form of grids, preferably including fins. In this example, the upstream end 15 is formed by a flat wall of the frame 16, extending transversely and provided with openings for the circulation of the airflow F, on which the light-emitting diodes 18 are fixed. Alternatively, in the example of [Fig.5], the walls of the frame 16 extend transversely with respect to the longitudinal axis X and their upstream end forms the upstream end 15 of the volumetric heat exchanger 10.

[0048] With reference to Figures 2 and 3, the light-emitting diodes 18, abbreviated as "LEDs", are electrically powered and adapted, in the active ON mode, to emit infrared radiation. The switching of the light-emitting diodes 18 between the active ON mode ([Fig. 2]) and the inactive OFF mode is performed by a device The control system is typically an aircraft turbomachine controller, known by the abbreviation "FADEC". Preferably, the active ON mode is driven when an airflow parameter F, for example, temperature, typically measured by a sensor on the aircraft turbomachine 1, falls below a predetermined threshold. The active ON mode can be driven cyclically, with the cycle duration depending on the airflow temperature F.

[0049] According to a preferred aspect illustrated in Figures 2 and 3, the light-emitting diodes 18 are integrated into a fixing strip 19 which is fixed to the upstream end 15 of the volumetric heat exchanger 10. This allows for simple and practical installation, typically by gluing to the upstream end 15. In this example, the fixing strip 19 extends vertically along a gravity axis G so as to cover the entire height L10 of the volumetric heat exchanger 10. Preferably, several fixing strips 19 provided with light-emitting diodes 18 cover the transverse surface of the upstream end 15 for effective overall defrosting. In the example of [Fig.5], the fixing strips 19 are fixed to the upstream end of the transverse walls of the frame 16. The fixing strip(s) 19 thus cover the upstream end 15 of the volumetric heat exchanger 10 while leaving the airflow passages F free.

[0050] In the example of [Fig. 4], light-emitting diodes 18 are also fixed to the outer surface 13 of the fluidic network 11, preferably integrated into one or more fastening strips 19, as well as to the upstream end 15. Also in this example, light-emitting diodes 18 are fixed to the downstream end 17 of the volumetric heat exchanger 10. Such light-emitting diodes 18 advantageously allow, under freezing conditions, the heating of the oil H to prevent it from freezing in the fluidic network 11. Such light-emitting diodes 18 also contribute to defrosting. [Fig. 5] illustrates another example where light-emitting diodes 18 are also fixed to the frame 16 to further defrost the airflow passages F.

[0051] With reference to Figures 2 to 5, the use of the aircraft turbomachine 1 according to the invention consists of electrically driving the light-emitting diodes 18 in the active ON mode in the presence of icing conditions, typically detected by one or more measuring sensors in the aircraft turbomachine 1 and / or cyclically. The active ON mode advantageously prevents the deposition and / or formation of ice by locally heating the upstream end 15 as well as the airflow F upstream of the upstream end 15. The active ON mode also allows, as a complementary measure, the heating of the structural arms 26 located upstream for de-icing purposes. Finally, the active ON mode can be used to heat the oil H in In certain cold conditions, it could freeze. The inactive OFF mode is controlled outside of icing conditions.

[0052] Thanks to the light-emitting diodes 18, the operation of the aircraft turbomachine 1 is improved and cooling capacity is increased. In particular, the light-emitting diodes 18 allow for localized de-icing, which is efficient and energy-saving. Furthermore, the size and mass of the light-emitting diodes 18 are minimal, allowing their integration into the tertiary stream 4 or the secondary stream 28 while limiting aerodynamic disturbances.

Claims

Demands

1. Aircraft turbomachine (1, 1') extending along a longitudinal axis (X) and comprising: • an air stream (4, 28) including an inner casing (6) and an outer casing (5) with respect to the longitudinal axis (X) together defining a free volume (V) in which an airflow (F) circulates from upstream to downstream during a thrust phase of the aircraft turbomachine (1, 1'), • at least one volume heat exchanger (10) including a fluidic network (11) extending in the free volume (V) of the air stream (4, 28), the fluidic network (11) including an internal surface (12) for guiding a fluid to be cooled (H) and an external surface (13) defining a plurality of passages (14) for circulating the airflow (F) so as to cool the fluid to be cooled (H), the exchanger volumetric heat (10) comprising a transverse height (L10) relative to the longitudinal axis (X) greater than 50% of a transverse height (L) of the air stream (4,28) defined between the inner casing (5) and the outer casing (6), • the aircraft turbomachine (1, 1') being characterized in that it comprises a plurality of infrared light-emitting diodes (18) fixed to an upstream end (15) of the volumetric heat exchanger (10) and electrically controllable between an inactive mode (OFF) and an active mode (ON) ensuring de-icing or preventing icing of the upstream end (15) of the volumetric heat exchanger (10).,

2. Aircraft turbomachine (1, 1') according to claim 1, wherein the transverse height (L10) of the volumetric heat exchanger (10) is greater than 80% of the transverse height (L) of the air stream (4, 28), preferably greater than 90%.

3. Aircraft turbomachine (1, 1') according to any one of claims 1 and 2, comprising at least one fastening ribbon (19) connecting the light-emitting diodes (18).

4. Aircraft turbomachine (1, 1') according to any one of claims 1 to 3, comprising a plurality of light-emitting diodes (18) in the infrared domain fixed on the external surface (13) of the fluidic network (11) of the volumetric heat exchanger (10) and electrically controllable between inactive mode (OFF) and active mode (ON).

5. Aircraft turbomachine (1, 1') according to any one of claims 1 to 4, comprising a plurality of infrared light-emitting diodes (18) fixed on a downstream end (17) of the volumetric heat exchanger (10) and electrically controllable between inactive (OFF) and active (ON) mode

6. Aircraft turbomachine (1, 1') according to any one of claims 1 to 5, wherein the volumetric heat exchanger (10) comprises a frame (16) housing the fluidic network (11) and on which are fixed a plurality of light-emitting diodes (18) in the infrared range electrically controllable between inactive mode (OFF) and active mode (ON).

7. Aircraft turbomachine (1) according to any one of claims 1 to 6, comprising from upstream to downstream: • an unshod fan (7), • an inlet stream (2) supplied with airflow (F) by the unshod fan (7), • a primary stream (3) comprising a combustion chamber (24) and a tertiary stream (4) extending around the primary stream (3), the primary stream (3) and the tertiary stream (4) being supplied with airflow (F) by the inlet stream (2), the tertiary stream (4) forming the air stream in which the volumetric heat exchanger (10) is mounted.

8. Aircraft turbomachine (1) according to claim 7, wherein the tertiary runner (4) comprises a plurality of structural arms (26) extending radially in the free volume (V) with respect to the longitudinal axis (X) and upstream of the volume heat exchanger (10).

9. Aircraft turbomachine (F) according to any one of claims 1 to 6, comprising from upstream to downstream: • a shrouded fan (27), • a primary runner (3) comprising a combustion chamber (24) and a shrouded secondary runner (28) extending around the primary runner (3), the primary runner

10. (3) and the secondary shrouded vein (28) being supplied with airflow (F) by the shrouded blower (27), the secondary shrouded vein (28) forming the air vein in which the volumetric heat exchanger (10) is mounted. Method of using an aircraft turbomachine (1, 1') according to any one of claims 1 to 9, consisting of electrically driving the light-emitting diodes (18) from the inactive mode (OFF) to the active mode (ON) so as to de-ice or prevent icing of the upstream end (15) of the volumetric heat exchanger (10).

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