AIRCRAFT TURBOMACHINE ASSEMBLY COMPRISING AN OUTLET DIRECTOR BLADE CROSSED BY A COOLING AIR CHANNEL

Abstract

The invention relates to an aircraft turbomachine assembly comprising, downstream of a receiver, a flow-separating nozzle (26) from which the turbomachine delimits a primary flow (28) and a secondary flow (30). The turbomachine also comprises, in the secondary flow (30), outlet guide vanes (40), as well as at least one element to be cooled (44a, 44b) and a cooling system (42) for this element. According to the invention, the cooling system (42) comprises: - at least one cooling air channel (50) passing through one of the outlet guide vanes (40); - a regulating valve (60) for the flow of cooling air through the cooling air channel (50); and - a control device (62) for the regulating valve (60). Figure 2

Description

Title of the invention: ASSEMBLY FOR AN AIRCRAFT TURBOMACHINE COMPRISING A GUIDE BLADE OUTLET CROSSED BY A COOLING AIR CHANNEL Technical field

[0001] The invention relates to an assembly for an aircraft turbomachine, and it relates more particularly to cooling systems intended to cool elements sensitive to temperature increases within the turbomachine. STATE OF THE PRIOR ART

[0002] Within aircraft turbomachines, certain elements must be cooled in order to maintain their proper functioning. These are, for example, measuring devices which must, during operation of the turbomachine, provide precise measurements of certain technical characteristics. In the event of overheating of these measuring devices, the data provided may be erroneous, thus involving, for example, risks in the control of the turbomachine. Other elements to be cooled may be components of a lubricant circuit, for example oil circulation pipes, or even casings of the turbomachine.

[0003] In all these examples, there is a need to cool the elements to be protected, in particular with regard to a rise in temperature likely to be caused by an increase in the leakage flow rates of hot gases in the turbomachine.

[0004] To address this problem, cooling air is conventionally taken from the primary flow of the turbomachine, i.e. upstream of the combustion chamber, in the primary flow. However, this solution remains improvable, firstly because the air taken from this location has already been at least partly compressed, which implies a high temperature for this taken air, making it unsuitable for a cooling function. In addition, this type of taking from the primary air flow impacts the overall performance of the turbomachine, since it is a part of the air flow intended to generate the thrust that is diverted. This leads to oversizing the primary flow, in order to achieve the expected thrust despite the air taken from it. Of course, this oversizing is detrimental to the size and overall mass of the turbomachine. Presentation of the invention

[0005] To address the drawbacks mentioned above, relating to conventional embodiments of the prior art, the invention relates to an assembly for tur- aircraft engine comprising a receiver intended to be rotated about a longitudinal central axis of the assembly, and intended to be crossed by an incoming air flow, the assembly comprising, downstream of the receiver, a flow separation nozzle from which the turbomachine delimits a primary vein intended to be crossed by a primary flow, as well as a secondary vein arranged around the primary vein and intended to be crossed by a secondary air flow, the assembly also comprising, in the secondary vein, outlet guide vanes, and comprising at least one element to be cooled, as well as a system for cooling the element to be cooled.

[0006] According to the invention, the cooling system comprises:

[0007] - at least one cooling air channel passing through one of the guide vanes of exit ;

[0008] - a valve for regulating a flow of cooling air through the air channel of cooling; and

[0009] - a device for controlling the regulating valve.

[0010] The invention advantageously provides, in a controlled manner, for passing a flow of cooling air through an outlet guide vane. This solution thus does not require any tapping of the primary flow. The performance of the turbomachine is thereby improved, and its overall mass can be reduced. Consequently, the invention corresponds to a result of technological research aimed at significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of these aircraft (decarbonization).

[0011] The invention preferably provides at least one of the following optional technical features, taken alone or in combination.

[0012] According to a preferred embodiment of the invention, the control device of the regulating valve is an electrical device, connected to one or more temperature and / or pressure sensors, placed on or near the element to be cooled.

[0013] According to another preferred embodiment of the invention, the control device of the regulating valve is a mechanical device, responding to an air pressure within the cooling system, or within the primary vein.

[0014] Preferably, the control valve is housed in the cooling air channel passing through the outlet guide vane, preferably in a part corresponding to the first third of this vane, starting from its internal radial end. This part in fact forms the traditionally thickest zone of the outlet guide vane, thus facilitating the installation of this control valve.

[0015] Preferably, the cooling air channel through the outlet guide vane is curved, preferably following the shape of a leading edge of this vane.

[0016] Preferably, the cooling system comprises a through conduit, com provided with an air outlet of the cooling air channel through the outlet guide vane, this passage duct being arranged to pass through the primary vein. Thus, the cooling system implemented in the invention advantageously makes it possible to cool elements located radially inwards relative to the primary vein of the turbomachine.

[0017] Preferably, the cooling air channel through the outlet guide vane comprises an air inlet opening radially at a head of this vane, as well as an air outlet opening radially at a root of this vane.

[0018] Alternatively, the cooling system comprises several cooling air channels passing through the outlet guide vane, each channel comprising an air inlet opening at a leading edge of this vane, and at least some of these channels joining at a common zone provided within this vane.

[0019] Preferably, said at least one element to be cooled is taken from at least one of the following elements:

[0020] - a measuring device;

[0021] - a lubrication circuit;

[0022] - a turbomachine casing.

[0023] Finally, it is noted that the receiver of the turbomachine is preferably a ducted fan, or an unducted propeller.

[0024] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below. Brief description of the drawings

[0025] The following detailed description refers to the accompanying drawings in which:

[0026] [Fig.l] is a schematic view in longitudinal section of an aircraft turbomachine, according to a preferred embodiment of the invention;

[0027] [Fig.2] is a schematic and enlarged view in longitudinal section of a part of the turbomachine shown in the preceding figure, more particularly showing a system for cooling measuring devices;

[0028] [Fig.3] is a schematic cross-sectional view of an outlet guide vane of the turbomachine shown in the previous figure;

[0029] [Fig.4] is a schematic view in longitudinal section of a part of the aircraft turbomachine, according to another preferred embodiment of the invention;

[0030] [Fig.5] is a schematic view in longitudinal section of a part of the aircraft turbomachine, according to another preferred embodiment of the invention;

[0031] [Fig.6] is a schematic view in longitudinal section of a part of the aircraft turbomachine, according to another preferred embodiment of the invention;

[0032] [Fig.7] is a schematic view in longitudinal section of the turbomachine aircraft, according to another preferred embodiment of the invention.

[0033] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0034] [Fig.l] represents a turbomachine 10 for an aircraft, which is of the double-flow turbomachine type and which has a symmetry of revolution around a main axis A1, corresponding to the longitudinal central axis of this turbomachine. This is a turbomachine with an unducted receiver, that is to say comprising an unducted propeller, this type of turbomachine also being called “Open Rotor”, or also called a turbojet with an unducted fan. This receiver can be driven directly by the gas generator of the turbomachine, or indirectly via a reducer.

[0035] Subsequently, the terms “upstream” and “downstream” are defined relative to a general direction SI of flow of the gases through the turbomachine 1, along the axis A1, when the turbomachine generates direct thrust. These terms “upstream” and “downstream” could respectively be substituted by the terms “front” and “rear”, with the same meaning.

[0036] In a known manner, the turbomachine 10 comprises an air inlet 14 through which an incoming air flow 16 passes before passing through an unducted propeller 18, which acted as a receiver for the turbomachine 10. Downstream of this propeller 18, the incoming air flow 16 is then separated into two flows 20, 22, via an intermediate inter-vein casing 24 whose end 26 forms a flow separation nozzle. The incoming air flow 16 is thus divided into a primary air flow 20 which is radially central relative to the axis A1, and an annular secondary air flow 22, which is arranged around the primary air flow 20.

[0037] The primary air flow 20 feeds a primary air circulation vein 28, in which a low pressure compressor, a high pressure compressor, a combustion chamber, a high pressure turbine and a low pressure turbine are arranged successively, from upstream to downstream.

[0038] The secondary air flow 22 feeds a secondary air circulation vein 30.

[0039] The primary vein 28 and the secondary vein 30 are concentric and centered on the axis A1, and as mentioned previously, the primary vein 28 is radially internal relative to the secondary vein 30. In this turbomachine 10 with unducted propeller 18, the internal radial delimitation of the secondary vein 30 is effected in part by the radially external surface of the inter-vein casing 24. On the other hand, there is no real physical delimitation of this vein 30 radially outward. In this respect, it is nevertheless accepted that this secondary vein 30 extends radially outward to the blade tips of the propeller 18.

[0040] At their respective upstream ends, the primary vein 28 and the secondary vein 30 are therefore separated radially from each other by the flow separator 26 of the casing 24.

[0041] Upstream, the propeller 18 is driven in rotation around the axis A1, and it comprises a fan rotor 32 which carries a plurality of movable blades 34, preferably steerable in incidence, and of radial main orientation.

[0042] The turbomachine also comprises, downstream of the propeller 18 and the flow separation nozzle 26, in the secondary vein 30, outlet guide vanes 40, also called OGV (from the English “Outlet guide Varie”). This is an annular row of fixed vanes, possibly controllable in incidence, which project radially outwards from the inter-vein casing 24. The heads of these vanes 40 also form a fictitious delimitation, radially outwards, of the secondary vein 30.

[0043] Referring now to [Fig. 2], a cooling system 42 specific to the present invention is shown. The system 42 is here provided for cooling one or more elements of the turbomachine, here two measuring devices, for example a telemetry device 44a as well as a thrust balance measuring device 44b. For information purposes, it may be an engine speed meter or an intrusive comb-type meter.

[0044] Other elements of the turbomachine than instrumentation elements may be cooled by the cooling system 42, such as components of a lubrication circuit, for example oil circulation conduits for the lubrication of one or more rolling bearings. According to yet another example, it may be a casing of the turbomachine, requiring cooling so as to limit the effects of thermal expansion.

[0045] In [Fig. 2], the two elements to be cooled 44a, 44b are housed in a cooled enclosure 46, thus forming an integral part of the cooling system 42. The enclosure 46 and the cooled elements 44a, 44b that it contains are arranged radially between the primary flow path 28, and the engine shafts 48 of the turbomachine. In addition, these elements 44a, 44b are located close to at least one of the outlet guide vanes 40, while being radially offset from the latter. Preferably, there is at least one fictitious transverse plane of the turbomachine which passes through at least a portion of the outlet guide vanes 40, as well as at least a portion of at least one of the two elements 44a, 44b. This partial overlap in the axial direction of the turbomachine in fact reflects a certain proximity between the outlet guide vanes 40 on the one hand, and the elements to be cooled 44a, 44b on the other hand.

[0046] The cooling system 42 has the particularity of comprising at least one cooling air channel 50, passing through one of the outlet guide vanes 40. Subsequently, only a single outlet guide vane 40 equipped with such a channel 50, even if several of these bladings 40 may be involved. Furthermore, in this preferred embodiment of the invention, only a single cooling air channel passing through the blading 40 will be described, even if several channels 50 could be provided within the same blading, without departing from the scope of the invention.

[0047] Here, the cooling air channel 50 comprises an air inlet 50a opening radially outwards, at the level of a head of this blading. In addition, it comprises an air outlet 50b opening radially inwards, at the level of a foot of this blading 40. The air outlet 50b is thus located at or near the radially external surface of the inter-vein casing 24, downstream of the separation nozzle 26.

[0048] With this design, during operation of the turbomachine, fresh air is taken at the level of the head of the blade 50, in the external flow, that is to say radially outwards relative to the secondary flow 22. A scoop system can equip the air inlet 50a of the channel 50, in order to improve the intake of cooling air. The cooling air then circulates radially inwards in the channel 50, up to the air outlet 50b. This outlet 50b is connected to a crossing duct 52, which allows the cooling air to circulate from this outlet 50b, up to an inlet 54 in the enclosure 46 to be cooled. To do this, the crossing conduit 52 runs essentially radially inwards, successively crossing an engine compartment 56 delimited between the two veins 28, 30, then it crosses the primary vein 28.At the level of its passage through the primary vein 28, the duct 52 is preferably surrounded by a cowling 58 in the form of a fixed blade, also called an “arm” of the outlet guide blade, due to its arrangement in the radial extension towards the interior of this blade 40. The flared shape of the crossing duct 52, going radially towards the interior as far as the inlet 54 of the enclosure 46, makes it possible to cool the air by expansion.

[0049] The cooling system 42 is completed by a valve 60 for regulating a cooling air flow rate through the cooling air channel 50, as well as by a device 62 for controlling the regulating valve 60. The valve 60 can be arranged in the through-duct 52, as shown in [Fig. 2], or directly in the cooling air channel 50. The control device 62 can be integrated into the valve 60, and here it takes the form of an electrical control device, preferably comprising a servomotor. As an input, this control device 62 receives signals from sensors 64a, 64b for temperature and / or air pressure, respectively placed on or near the elements to be cooled 44a, 44b.Depending on the signals received and when the data reflects a critical temperature with respect to heating of the elements 44a, 44b to be protected, the control device 62 orders an opening of the valve 60, in order to generate or increase the flow of cooling air through the cooling system 42.

[0050] The production of the outlet guide vane 40 can be carried out using different manufacturing techniques, in particular by additive manufacturing for metal vanes. In the example shown in [Fig. 3], the main body of the vane 40 is made of ceramic matrix material (called “MMC” material), with a leading edge part 66 added to this body, this part preferably being metallic. The cooling air channel 50 is then preferably defined between the MMC main body of the vane, and the added part 66. The cooling air channel 50 through the outlet guide vane 40 is then preferably curved, following the shape of a leading edge 68 of this vane all along the latter in the radial direction, as is also shown in [Fig. 2].

[0051] Thus, the invention relates more particularly to an assembly 100 intended to equip the turbomachine 10, the assembly 100 being centered on the axis A1 and comprising in particular the receiver 18, the flow separation nozzle 26, the outlet guide vanes 40, the elements to be cooled 44a, 44b, and the cooling system 42.

[0052] [Fig. 4] represents another preferred embodiment of the invention, in which the control device of the regulating valve 60 is a mechanical device 162, responding to an air pressure. More precisely, the valve 60 is here housed in the cooling air channel 50, preferably in a radially internal part 70, corresponding to the first third of this blading starting from its internal radial end. This part corresponds to the thickest zone of the blading 40, which makes it easier to install the valve. In addition, the mechanical control device 162 can be integrated into the valve body, in the channel 50, so as to control the opening of this valve 62 as a function of the air pressure in the channel 50, and more precisely in its part located between the valve 60 and the head of the blading 40.In practice, when the control device 162 receives sufficient air pressure in the radially external part of the cooling air channel 50, this air pushes for example a piston provided to open the valve 60 and allow the air to pass, in order to cool the elements 44a, 44b. The advantage of such a mechanical solution also lies in the fact that at low air pressure in the channel 50, the valve 60 remains closed and consequently ensures the sealing of the enclosure 46 containing the elements to be cooled 44a, 44b.

[0053] In another preferred embodiment of [Fig. 5], the mechanical control device 162 of the regulating valve 60 has the particularity of responding to the air pressure within the primary stream 28. To do this, an aerodynamic fin 72 is pivotally mounted in the primary stream 28. Depending on the intensity of the aerodynamic forces of the primary flow 20 which are applied to the fin 72, the latter undergoes a more or less high rotation. This rotation is transmitted to a flap 74 of the valve 60, via a mechanical transmission device 78 forming an integral part of the mechanical control device 162, and which comprises for example angle gears.

[0054] Thus, when the pressure of the primary air flow 20 increases in the vein 28, the regulating valve 60 opens further, resulting in increased cooling of the elements 44a, 44b.

[0055] In another preferred embodiment of the invention, shown in [Fig. 6], the cooling system 52 comprises several cooling air channels 50 passing through the outlet guide vane 40. They no longer necessarily open radially outwards at the vane head, but at least some of them have an air inlet 50a opening at the leading edge 68 of this vane, at different radial heights. These channels 50 can join at a common zone 80 preferably provided within this vane 40, and which communicates at its outlet with the crossing duct 52. In this solution, the control valve (not shown in [Fig. 6]) is preferably located in the common zone 80 of the multiple channels 50, or in the crossing duct 52 which extends this common zone 80.

[0056] Various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims. In this regard, it is noted that all the features disclosed above, in the various preferred embodiments and their alternatives, are combinable with each other. Moreover, it is noted that in all the figures which have been described above, the elements which bear the same numerical references correspond to identical or similar elements.

[0057] Finally, it is noted that the application of the invention is not limited to a turbomachine with an unducted propeller / fan, but it also applies to any other type of aircraft turbomachine, such as a turbojet with a ducted fan, of the type shown in [Fig. 7]. In this application, the secondary vein 30 is delimited radially outwards by a nacelle 12 and / or by a fan casing. Thus, the supply of the cooling air channel through the outlet guide vane 40 is carried out either by air coming from inside the nacelle, or by air coming from outside the nacelle, or by air from the secondary flow.

Claims

Claims

1. Assembly (100) for an aircraft turbomachine (10) comprising a receiver (18) intended to be rotated about a longitudinal central axis (A1) of the assembly, and intended to be traversed by an incoming air flow (16), the assembly comprising, downstream of the receiver (18), a flow separation nozzle (26) from which the turbomachine delimits a primary vein (28) intended to be traversed by a primary flow (20), as well as a secondary vein (30) arranged around the primary vein and intended to be traversed by a secondary air flow (22), the assembly also comprising, in the secondary vein (30), outlet guide vanes (40), the assembly comprising at least one element to be cooled (44a, 44b), as well as a system (42) for cooling the element to be cooled, characterized in that the cooling system (42) comprises: - at least one air channel cooling (50) passing through one of the outlet guide vanes (40);- a control valve (60) for controlling a cooling air flow through the cooling air channel (50); and - a device (62, 162) for controlling the control valve (60).;

2. Turbomachine assembly according to claim 1, characterized in that the control device of the regulating valve is an electrical device (62), connected to one or more temperature and / or pressure sensors (64a, 64b), placed on or near the element to be cooled (44a, 44b).

3. Turbomachine assembly according to claim 1, characterized in that the control device of the regulating valve is a mechanical device (162), responding to an air pressure within the cooling system (42), or within the primary vein (28).

4. Turbomachine assembly according to any one of the preceding claims, characterized in that the control valve (60) is housed in the cooling air channel (50) passing through the outlet guide vane (40), in a part (70) corresponding to the first third of this vane, starting from its internal radial end.

5. A turbomachine assembly according to any one of the preceding claims, characterized in that the cooling air channel (50) through the outlet guide vane (40) is curved, following the shape of a leading edge (68) of this vane (40).

6. Turbomachine assembly according to any one of the preceding claims, characterized in that the cooling system (42) comprises a through duct (52), communicating with an air outlet (50b) of the cooling air channel (50) through the outlet guide vane (40), this through duct (52) being arranged to pass through the primary vein (28).

7. Turbomachine assembly according to any one of the preceding claims, characterized in that the cooling air channel (50) through the outlet guide vane (40) comprises an air inlet (50a) opening radially at a head of this vane, as well as an air outlet (50b) opening radially at a root of this vane.

8. Turbomachine assembly according to any one of the preceding claims, characterized in that the cooling system (42) comprises several cooling air channels (50) passing through the outlet guide vane (40), each channel (50) comprising an air inlet (50a) opening at a leading edge (68) of this vane, and at least some of these channels (50) joining at a common zone (80) provided within this vane (40).

9. Turbomachine assembly according to any one of the preceding claims, characterized in that said at least one element to be cooled (44a, 44b) is taken from at least one of the following elements: - a measuring device; - a lubrication circuit; - a turbomachine casing.

10. Turbomachine assembly according to any one of the preceding claims, characterized in that the receiver (18) is a ducted fan, or an unducted propeller.

11. Aircraft turbomachine comprising at least one assembly (100) according to any one of the preceding claims.

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