DE-ICING DEVICE FOR A TURBOMACHINE SPOUT

Abstract

The invention relates to a de-icing device intended to supply de-icing air for a turbomachine separation nozzle extending along a longitudinal axis, said turbomachine comprising: - the separation nozzle which is intended to be positioned downstream of a fan of the turbomachine and comprising an inner casing and an outer casing to form a separation between a primary flow vein of a primary flow and a secondary flow vein (II) of a secondary flow, said flows coming from the fan, said inner casing and said outer casing defining an inter-vein space; - guide vanes of said turbomachine intended to be fixed by screws (4) to the inner casing, so that said screws extend into the inter-vein space, said de-icing device being intended to be positioned in the inter-vein space and comprises - an air inlet (31); - an air outlet (32);- a plurality of channels (33) extending from the air inlet (31) to the air outlet (32); the channels (33) being arranged relative to each other so that they are intended to extend from the air inlet (31) to the air outlet (32) passing between the screws (4) for fixing the guide vanes.;

Description

GENERAL TECHNICAL FIELD The invention relates to the general field of turbomachinery. More particularly, the invention relates to a device for de-icing the front parts of a turbomachine, and more specifically, the separation nozzle of a turbomachine. The invention also relates to a de-icing nozzle equipped with such a device, as well as a turbomachine comprising such a de-icing device. STATE OF THE ART In a twin-spool, twin-flow turbomachine, the primary and secondary flow streams are separated downstream of the fan by a separation nozzle. Such a separation nozzle of a twin-flow turbomachine comprises an inner casing and an outer casing. Within the primary stream, at the inlet of the low-pressure compressor (also called booster) are a set of stator and rotor blades for the progressive compression of the primary airflow. During certain phases of flight and on the ground, the turbomachine may encounter icing atmospheric conditions, particularly when ambient temperature is low and humidity is high. Under these conditions, ice can form on the separation nozzle and the blades, such as those of the first row of stator blades encountered by the primary airflow. When this occurs, it can lead to partial obstruction of the primary airflow and the ingestion of ice fragments that have broken off. An obstruction of the primary airflow results in insufficient fuel supply to the combustion chamber, which can then shut down or prevent the engine from accelerating. In the case of ice fragments that break off, these can damage the downstream compressor and lead to a reduction in blade life, thus increasing the turbomachine's maintenance costs. To prevent ice formation on the separation nozzle, techniques exist that involve drawing hot air from the primary stream, using at least one de-icing tube, at a compressor and injecting it into an upstream end cavity inside the separation nozzle. The hot air injected into the separation nozzle can then travel through the nozzle to bores or... grooves configured to inject hot air into the primary stream which can also de-ice the rotor and stator blades, in particular by spraying hot air on the first row of stator blades at the primary stream inlet. One such solution is, for example, in document US 2003 / 0035719 A1, in particular by considering figure 2 of that document. One problem is that each stator blade may have a radial mounting system on the internal housing, which can be bulky when screw-on. Furthermore, the inter-vein spacing is constrained by the mounting system and the size of the defrosting tubes in the separation nozzle. A challenge is to optimize the sizing and geometry of the defrosting tube to allow for efficient cavity air supply without the mounting system necessitating an increase in nozzle volume for effective defrosting. Indeed, sufficient space must be allocated to accommodate the defrosting tube. However, the need for space in the inter-vein space directly influences the shape of the aerodynamic veins of the primary and secondary flow with significant impacts on performance and mass, therefore the amount of fuel consumed by the engine. PRESENTATION OF THE INVENTION The invention proposes to overcome at least one of these drawbacks. To this end, the invention proposes, according to a first aspect, a defrosting device intended to supply defrosting air to a turbomachine separation nozzle extending along a longitudinal axis, said turbomachine comprising: - the separation nozzle which is intended to be positioned downstream of a turbomachine blower and comprising an inner casing and an outer casing to form a separation between a primary flow channel of a primary flow and a secondary flow channel of a secondary flow, said flows originating from the blower, said inner casing and said outer casing defining an inter-channel space; - guide vanes of said turbomachine intended to be fixed by screws to the internal casing, such that said screws extend into the inter-vein space, said de-icing device being intended to be positioned in the inter-vein space and comprises - an air intake: - an air outlet; - a plurality of channels extending from the air inlet to the air outlet; the channels being arranged in relation to each other so that they are intended to extend from the air inlet to the air outlets by passing between the fixing screws of the guide vanes. The invention is advantageously complemented by the following Features, taken alone or in any technically feasible combination thereof: The channels extending from the air inlet to the air outlet are cylindrical; the air inlet and / or the air outlet has a cylindrical section; one of the channels extends longitudinally between the air inlet and the outlet of air. It includes five channels. The device was produced using additive manufacturing. The invention proposes, according to a second aspect, a method for manufacturing a de-icing device for a separation nozzle of a turbomachine according to the first aspect of the invention, in which said nozzle is obtained by means of additive manufacturing, preferably of the laser powder fusion type. The invention proposes, according to a third aspect, a defrosting assembly comprising a plurality of defrosting devices according to the first aspect of the invention, the defrosting devices being intended to be arranged in the inter-vein space around the internal casing, the air inlets of each of the defrosting devices being connected to each other by a hot air supply duct configured to bring hot air to each air inlet. The invention proposes according to a fourth aspect a separation nozzle of a turbomachine comprising an inner casing and an outer casing delimiting an inter-vein space, said nozzle comprising a de-icing assembly according to the preceding claim, disposed in the inter-vein space. Thus, compared to the state of the art, the defrosting tube provided in the inter-vein space is replaced by several pipes which pass between the attachment systems of the stator blades fixed to the internal casing. Having a defrosting device integrated between the screws of the inter-vein space of the separating nozzle helps to reduce the inter-vein bulk. In this way, the aerodynamic / engine performance compromise is greatly improved compared to known solutions. PRESENTATION OF THE FIGURES Other features, purposes and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings, in which, in addition to Figure 1 already discussed: - Figure 1 illustrates a separation nozzle of a double-flow turbomachine comprising a de-icing device according to the invention; - Figure 2 illustrates a defrosting device according to the invention; - Figures 3a and 3b each illustrate a defrosting assembly according to two variants of the invention. Across all figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates a separation nozzle 1 of a double-flow turbomachine comprising a de-icing device 30 according to the invention. As already mentioned, the nozzle 1 includes an inner casing 11 and an outer casing 12. In addition, within the primary stream |, at the inlet of the low pressure compressor 2 and then downstream are sets of stator blades 22, 22a and then rotor blades 21 for the progressive compression of the primary air flow FI. An upstream row of stator blades 22a includes guide blades which are the first blades impacted by the primary flow FI in the primary air stream inlet |. To prevent ice from forming on the separation nozzle 1, a defrosting unit supplies defrosting air initially drawn from at the compressor level via at least one tube 3 so that air can be injected into an upstream end cavity 13 inside the separation nozzle 1. The hot air injected into the separation nozzle 1 can then travel through this cavity of the nozzle 1 to drillings or grooves 131 allowing the hot air to be injected into the primary stream | so as to be able to defrost the blades, in particular by spraying hot air on the first inlet guide row comprising stator blades 22a. Each stator blade 22, 22a has a radial attachment system 4 on the internal housing 11. In the embodiment shown, the first inlet guide row comprising stator blades 22a is, for example, welded to the housing 11. The other stator rows of guide blades 22 have a screw attachment system with large screws 4. Therefore, the inter-row space 10 is constrained by the attachment system and by the size of the defrosting devices 30 of the separation nozzle 1. As can be seen in Figure 1, the attachment systems 4 require sufficient space to accommodate the hot air defrosting devices 30. With reference to Figure 1, the defrosting assembly comprises several defrosting devices 30 as illustrated on the one hand in Figure 2 and on the other hand in Figures 3a and 3b. These devices are arranged in the inter-vein space as illustrated in Figures 3a and 3b for example. Each defrosting device 30 intended to be positioned in the inter-vein space comprises an air inlet 31 and an air outlet 32. The airflow is represented by an arrow in Figure 2. The air inlet 31 and the air outlet 32 ​​are located opposite each other and are preferably each formed by a cylinder. Each defrosting device 30 is, for example, made of a material such as a nickel-based alloy like Inconel 625 or, where appropriate, a steel capable of withstanding the temperatures of the hot defrosting air. Channels 33 extend from the air inlet 31 to the air outlet 32. The channels 33 are configured to bring hot air entering through the air inlet 31 to the air outlet 32 ​​by extending from the air inlet 31 to the air outlet 32 ​​by passing between the screws 4 of the fixing systems for the stator blades 22 fixed to the internal casing 11. Channels 33 are preferably cylindrical but can take other shapes. For example, between collectors associated with inputs and outputs, the channels can be at least partially straight by extending substantially longitudinally considering a parallel to the general axis of rotation in the turbomachine and the overall direction of airflow in the turbomachine (see Figure 3a). As can be seen in Figure 2, curved channels are located on either side of a central, straight channel between the air inlet 31 and the air outlet 32. The further the channels are from the central channel, the more pronounced their radius of curvature. This is because all the channels must originate from the air inlet 31 and reach the air outlet 32. In the case of Figure 2, this air outlet 32 ​​opens directly into cavity 13, for example, by passing through a corresponding orifice in a radial ferrule 111 of the inner casing 11. In this figure, the defrosting device 30 comprises five channels; of course, a different number may be used. The number of channels will depend on a compromise, in particular between the maximum flow rate for each defrosting device, the circumferential spacing between the mounting system screws, the radially available height in the inter-channel space, the pressure drop resulting from the channel connections, and, for example, the allocated mass of material to ensure the device is sufficiently robust. Such a de-icing device is advantageously obtained using an additive manufacturing process, preferably laser melting of a nickel-based or steel-type alloy powder. This process makes it possible to obtain complex shapes like the one shown in Figure 2. In relation to Figures 3a and 3b, a defrosting assembly disposed in the separation nozzle comprises several defrosting devices as described above. Each of these devices has a manifold outlet 32 ​​extending circumferentially in relation to its corresponding sector in the circumferential cavity 13. In this embodiment, each manifold outlet 32 ​​has at least one air outlet into the cavity 13. As can be seen in these figures, the de-icing devices 30 are intended to be arranged around the internal housing 11 of the turbomachine's de-icing nozzle in the inter-vein space 10, the air inlets 31 of each of the de-icing devices being connected to each other by a hot air supply duct 34 configured to bring hot air to each air inlet. The duct 34 hot air supply is itself supplied by at least one 3 general hot air supply tube. The supply conduit 34 is circumferential and follows the shape of the internal casing and preferably extends between two rows of stator blade fixing screws.

Claims

CLAIMS 1. Separator nozzle intended to be positioned downstream of a fan of a turbomachine, the separator nozzle comprising an internal casing (11) and an external casing (12) for forming a separation between a primary flow vein (I) of a primary flow (Fl) and a secondary flow vein (II) of a secondary flow (Fil), said flows coming from a fan of the turbomachine, said internal casing (11) and said external casing (12) defining an inter-vein space (10); a defrosting device for supplying defrosting air to the separation nozzle (1), the defrosting device extending along a longitudinal axis, said device comprising: - screws extending into the inter-vein space fixing guide vanes (22) of said turbomachine to the internal casing (11), so that said screws extend into the inter-vein space (10), said defrosting device being intended to be positioned in the interveinal space and comprises - an air inlet (31); - an air outlet (32); - a plurality of channels (33) extending from the air inlet (31) to the air outlet (32); the channels (33) being arranged relative to each other so that they are intended to extend from the air inlet (31) to the air outlet (32) passing between the screws (4) for fixing the guide vanes (22).

2. Spout, according to claim 1, wherein the channels (33) extending from the air inlet to the air outlet are cylindrical.

3. Spout according to one of the preceding claims, in which the air inlet and / or the air outlet has(have) a cylindrical section.

4. Spout according to one of the preceding claims, in which one of the channels extends longitudinally between the air inlet and the air outlet.

5. Spout according to one of the preceding claims, comprising five channels.

6. Defrosting nozzle according to one of the preceding claims, wherein said defrosting device has been obtained by additive manufacturing. 5 7. Method for manufacturing a separation nozzle according to one of the preceding claims, in which said nozzle is obtained by means of additive manufacturing, preferably of the laser fusion type of a powder. 10 8. A nozzle according to any one of claims 1 to 6, comprising a plurality of defrosting device, the defrosting devices being intended to be arranged in the inter-vein space (10) around the internal casing (11), the air inlets (31) of each of the defrosting devices being connected to each other by a hot air supply duct (34) configured to bring hot air to each inlet 15 (31) of air.

9. Turbomachine comprising a separation nozzle according to any one of claims 1 to 6 or according to claim 8 and guide vanes (22) fixed to the internal casing (11) by screws extending into the inter-vein space.

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