FR3028576A1 - TURBOMACHINE STATOR AUBING SECTOR COMPRISING HOT FLUID CIRCULATION CHANNELS - Google Patents

Abstract

A turbomachine stator-blasting sector comprising at least one blade (11, 12), an outer plate (18) connected to the outer end of the blade, and an inner plate (16) connected to the end interior of dawn. At least a first and a second channel (25, 27) are formed in the blade (11, 12) to allow, when the turbomachine is operating, a heat exchange between a hot fluid circulating in these channels and a cold air flow passing through the stator vane (9). The first and second channels (25, 27, 35, 37) are adjacent and belong respectively to separate first and second circuits (21, 31) having fluid inlets (22, 32) and outputs (23, 33) such as that the direction of radial circulation of the fluid in the first channel (25, 27) is opposite to the direction of radial circulation of the fluid in the second channel (35, 37).

Description

TECHNICAL FIELD The present invention relates to the field of heat exchangers installed in turbomachines. The invention also relates to the stator vanes which equip such turbomachines. The invention applies to any type of turbomachine, terrestrial or aeronautical, and in particular to an aircraft engine such as a turbojet or a turboprop. 10 BACKGROUND The oil circuit of an aircraft engine provides the dual task of lubricating the rotating parts of the engine and removing the heat released in the engine. In order to cool the oil, the temperature of which generally does not exceed about 200 ° C for reasons of efficiency, different types of heat exchangers exist. Some heat exchangers use air as a cold source. These are oil / air heat exchangers or "ACOC" for "Air Cooled Oil Cooler". Two types of oil / air exchangers are usually used: block exchangers and finned exchangers. The finned exchangers (or "surface coolers") have a generally rectangular surface on which oil flow channels are attached on one side of the surface and on the other side of the surface, blades or metal fins for the flow of air. The heat can thus be transferred from the hot oil to the metal blades 25 by thermal conduction, these fins cooling in contact with the air. This type of exchanger is usually placed directly on the walls of a vein of air from the engine. In a double flow turbojet, the cold air in the vein of the secondary flow is generally used for oil / air heat exchange. 30 302 8 5 7 6 2 Block exchangers (or "brick cooler" in English) conventionally consist of a stack of metal plates traversed by the fluid to be cooled. These plates are spaced from each other and metal strips are placed between these plates, the latter being generally welded. The plates are supplied with fluid by orthogonal distributor pipes to these plates. The oil and air circuits remain segregated. The whole is placed in a stream of air, either directly in the vein or in a channel fed by a scoop. The aforementioned exchangers have the disadvantage of adding rubbed surfaces (fins or plates) in the air flow and, therefore, to generate significant pressure drops which penalize the engine performance. Finally, patent document WO 2013150248 A1 describes a stator blade of a turbomachine formed by a plurality of parts arranged relative to one another to define air flow passages between these parts. Oil to cool circulates in channels in the different parts of the blade. Although satisfactory, this solution is relatively complex. GENERAL PRESENTATION The present disclosure relates to a stator vane sector of a turbomachine. This sector comprises at least one blade, an outer plate (also called "platform") connected to the outer end of the blade, and an inner plate connected to the inner end of the blade. This blading area is used as a heat exchanger.

By "stator vane sector" is meant a portion of the stator vane of the turbomachine. This part comprises a number of vanes and is delimited, internally and externally, by trays (also called platforms, or walls) extending in the circumferential direction of the vane and connecting the ends (inner / outer) of the vanes between them. The number of blades of a blading sector 3028576 3 is greater than or equal to one and less than or equal to the total number of blade blades. In general, in the present description, the axial direction corresponds to the direction of the axis of rotation of the rotor of the turbomachine, and s a radial direction is a direction perpendicular to this axis. Similarly, an axial plane is a plane containing the axis of rotation of the rotor, and a radial plane is a plane perpendicular to this axis. The circumferential direction corresponds to the direction of the circumference of the stator vane of the turbomachine.

On the other hand, unless otherwise stated, the adjectives "inner" and "outer" are used with reference to a radial direction so that the inner (ie radially inner) part of an element is closer to the axis of rotation than the outer (ie radially outer) part of the same element.

Finally, upstream and downstream are defined with respect to the normal flow direction of the fluid (from upstream to downstream) between the stator vanes. At least one first channel is formed in the blade, the first channel and the blade being adapted to allow, when the turbomachine operates, a heat exchange between a hot fluid flowing in the first channel 20 and a cold air flow through the stator vane (ie passing between the vanes of the vane). In general, the heat exchange between the hot fluid and the cold air flow will depend on the distance between the first channel and the surface of the blade which is licked by the cold air flow, as well as thermal conduction of the constituent material of the blade. For example, the blade may be made of a metal or metal alloy having good thermal conductivity. In what follows, "air" means any gas that can be used as an oxidant in a turbomachine. Furthermore, at least one second channel is formed in the blade, the second channel and the blade being adapted to allow, when the turbine engine is operating, a heat exchange between a hot fluid 3028576 4 flowing in the second channel and a flow of cold air passing through the stator blade. The first and second channels are adjacent and belong respectively to first and second discrete circuits having fluid inlets and outlets such that the radial flow direction of the hot fluid in the first channel is opposite to the direction of radial circulation of the hot fluid. in the second channel. The first and second circuits of which said "distinct" in that the first circuit is not part of the second circuit, or vice versa. On the other hand, the first and second channels are said to be "adjacent" in that they extend side by side. Such characteristics are useful for homogenizing the temperature on the surface of the blade. Indeed, the temperature of the hot fluid tends to decrease as it advances in its circuit. Also, by providing at least two (e.g., two or four) adjacent circuits with opposing flow directions, the temperature decreases in the two circuits compensate each other. This makes it possible to obtain the desired temperature homogeneity, which may have beneficial effects on the mechanical strength of the blading sector, the homogeneity of the air distribution in the vein and / or the effectiveness of the the heat exchange performed.

In certain embodiments, the first and second circuits extend over the outer plate and / or the inner plate and are such that, in this plate, the circumferential circulation direction of the hot fluid in the first circuit is opposite to the direction circumferential circulation of the hot fluid in the second circuit. This makes it possible to homogenize the temperature at the surface of the tray. In some embodiments, at least one other channel is formed in the blade, this other channel and the blade being adapted to allow, when the turbomachine is operating, a heat exchange between a hot fluid circulating in this other channel and a flow cold air passing through the stator vane. This other channel is adjacent to the first and second channels and belongs to another circuit distinct from the first and second circuits. In particular, third and fourth channels adjacent the first and second channels may be provided in the blade. The circulation of the fluid in these channels may be such that the direction of radial circulation of the hot fluid in two of the channels is opposite to the direction of radial circulation of the hot fluid in the other two channels. This again is a configuration to homogenize the temperature on the surface of the dawn. The hot fluid can be a liquid, in particular oil. As an alternative to oil, the hot fluid may be a heat transfer fluid with a heat capacity greater than that of air or even that of the oil. In some embodiments, the blades are output straightening vanes or "OGVs" for "Outlet Guide Vane" in English. In particular, it may be secondary flow rectifying blades disposed at the outlet of the fan in a turbofan engine.

The use as heat exchange surfaces of the existing surfaces of the inner or outer plate surfaces and / or the blade surfaces themselves has the advantage of limiting the pressure losses compared to a heat exchanger. placed in the vein of fluid passing through the turbomachine, such a heat exchanger therefore implying additional loss of aerodynamic thrust. In addition, in the case of an aircraft engine and when the vanes are exit straightening vanes placed in the secondary vein, the heat transfer from the hot fluid (for example oil) to the air represents an additional supply of energy into the secondary vein which is beneficial for engine performance. In addition, this heat input takes place over the entire height of the vein, which makes this solution more thermodynamically efficient than most known solutions. The present disclosure also relates to a turbomachine stator vane comprising a plurality of vane modules each extending over an angular sector of the vane, the vane being formed by butt-tying the modules. At least one of these modules may be formed by a blading sector as previously described. A bladder module may therefore comprise, in its interior, at least one circuit for the circulation of a hot fluid, extending between an inlet and a fluid outlet. This input and this output may, for example, be arranged on opposite sides of the module. This module configuration allows flexibility in terms of maintenance and assembly, compared to a system where each blade would be traversed by a circuit and where these circuits would be independent of each other.

The present disclosure also relates to a turbomachine comprising at least one stator vane sector as previously described. Other features and advantages of the proposed blade sector will appear on reading the detailed description which follows, of exemplary embodiments. This detailed description refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are diagrammatic and are not to scale, they are primarily intended to illustrate the principles of the invention. In these drawings, from one figure (FIG) to the other, identical elements (or element parts) are identified by the same reference signs.

FIG. 1 is an axial half-section of an example of an airplane turbojet engine. FIG 2 is a perspective view of an example of a stator vane sector of a turbomachine. FIG 3 is a sectional view of the blading sector of FIG 2, in the radial plane the sector being shown in the unassembled state. FIG 4 is a sectional view of the inner plate of the sector of FIG 2, according to the plane IV-IV of FIG 3, showing the channels formed in this plate. FIG. 5 is a sectional view, similar to that of FIG. 4, showing another channel configuration.

FIG. 6 is a simplified representation of another example of blading sectors. FIG 7 is a simplified representation of another example of blading sector.

FIG. 8 is a simplified representation of a possibility of mounting several adjacent two-to-two vane sectors in a stator vane. FIG 9 is a perspective view of another example of a stator blade.

FIG. 10 is a sectional view of the blade of FIG. 9 along the X-X plane perpendicular to the radial direction. DETAILED DESCRIPTION OF EXAMPLE (S) Exemplary embodiments are described in detail below, with reference to the accompanying drawings. These examples illustrate the features and advantages of the invention. However, it is recalled that the invention is not limited to these examples. FIG 1 is an axial half-section of the upstream portion of a double-flow double-body aircraft turbojet engine. A stator vane 9 is disposed downstream of the fan 2 of the turbojet engine in the secondary air stream 3. The stator vane 9 comprises an annular inner wall 13 and an annular outer wall 14 between which blades 11 of output recovery (or "OGV"). These vanes 11 are evenly distributed around the rotational axis A of the rotor of the turbojet engine. The inner and outer annular walls 13 have a generally cylindrical shape of an axis A. In one embodiment, the stator vane 9 is formed of several modules connected end to end, each module comprising at least one blade and extending over an angular sector of the vane. The modules can all be identical, but not necessarily. Some or all of these modules may be used as heat exchangers. The heat exchanger modules are, for example, of the same type as the blading sector 10 shown in FIG. 2. A possibility of mounting several blading sectors is described later with reference to FIG. FIG 8. In the example of FIG. 2, the blading module or sector 10 comprises two blades 11, 12 extending radially between an inner plate 16 and an outer plate 18. The inner plate 16 extends circumferentially between the inner ends of the blades 11, 12 and beyond these ends, while the outer plate 18 extends circumferentially between the outer ends of the blades 11, 12 and 10 beyond these ends. When the blading sector 10 is integrated with the stator vane 9, the inner 16 and outer 18 platens each form a portion of the inner annular walls 13 and outer 14, respectively. The inner plate 16 may be attached to an annular wall of a hub casing which internally delimits a portion of the vein of the secondary flow. The outer plate 18 may be fixed on an annular wall of a fan casing which delimits externally the same portion of the vein of the secondary flow. In FIG 2, the inner and outer plates 16, 18 and the blades 11, 12 are shown in dashed lines, so as to better visualize the oil circuits 21, 31 formed in the blading sector 20 10. Both Oil circuits 21, 31 are distinct and both comprise an inlet 22, 32 and an outlet 23, 33 of fluid. In the example, the inlet 22 and the outlet 23 of the first circuit 21 are respectively located at the ends of the inner plate 16, while the inlet 32 and the outlet 33 25 of the circuit 31 are respectively located at the ends of the outer plate 18 Furthermore, the inlet 32 of the circuit 31 is located at the end of the outer plate 18, on the same side of the blade 11 as the inlet 22 of the circuit 21. The ends of the plates have been shown relatively close to the one or other of the blades. It is nevertheless possible to lengthen the inner and outer plates 16 in the circumferential direction without changing the inter-blade spacing, so as to be able to obtain the same spacing between the blades, that is to say that is to say obtain a regular distribution of the blades over an angular extent of the vane constituted by several modules 10 connected end to end. In this case, it remains advantageous to arrange the inlets and outlets of the two oil circuits near the ends of the trays, in order to use as much as possible the surfaces of the trays for the heat exchange between the oil circuits and the trays. air of the vein of the secondary flow that licks these surfaces. The channels 24, 28, and 32, 34 described in the following are then generally elongated in the circumferential direction of the trays.

In order to mount each module 10 at its location in the flow of the secondary flow and to fluidly connect it to a neighboring module 10, there can be provided in the annular hub casing and in the annular fan casing lights corresponding to the positions inputs and outputs of the fluid circuits of each module. In this way, the connection 15 of the fluid circuits from one module to another can be done by means of pipes, for example flexible pipes, connected to the modules and passing through the housings by the corresponding lights. With modules such as that of the example of FIG. 2, the output of a fluid circuit of a module can be connected to the input of the same fluid circuit on the neighboring module. Each circuit 21, 31 comprises two substantially parallel branches which meet at the input and at the output of the circuit. Each circuit 21, 31 could, however, comprise only one branch. In the example, the circuits 21, 31 are substantially symmetrical to one another with respect to a median surface passing between the trays 16, 18. From its inlet 22 to its outlet 23, the first circuit 21 comprises: two channels 24 (one for each branch) formed in the thickness of the inner plate 16, two channels 25 formed in the thickness of one of the blades 11 and 30 extending over the entire height of the blade 11, from the inner plate 16 to the outer plate 18, 302 85 76 10 - two channels 26 formed in the thickness of the outer plate 18 and extending between the blades 11 and 12, - two channels 27 formed in the thickness of the other blade 12 and extending over the entire height of this blade 12, from the outer plate 18 to the inner plate 16, and - two channels 28 formed in the thickness of the inner plate 16. In a similar manner and symmetrical, its input 32 to its output 33, the circuit 31 comprises: - two canau x 34 (one for each branch) formed in the thickness of the outer plate 18, - two channels 35 formed in the thickness of the blade 12 and extending over the entire height of this blade 12, - two channels 36 formed in the thickness of the inner plate 16 and extending between the blades 11 and 12, 15 - two channels 37 formed in the thickness of the blade 11 and extending over the entire height of the blade 11, and - two channels 38 formed in the thickness of the outer plate 18. In the blades 11, 12, the direction of flow of the oil in the first circuit 21 is opposite to the direction of flow of the oil in the second circuit 31. More particularly, in this example, the oil of the first circuit 21 circulates radially from the inside to the outside in the blade 11 (ie in the channels 25) while the oil of the second circuit 31 flows radially from the outside to the inside in the blade 11 (i.e. in the channels 37). In addition, the oil of the first circuit 21 circulates radially from the outside to the inside 25 in the vane 12 (ie in the channels 27) while the oil of the second circuit 31 circulates radially from the inside to the outside. outside in the blade 12 (ie in the channels 35). This cross circulation makes it possible to ensure satisfactory homogeneity of the temperature at the surface of the blades 11, 12. In FIG. 2, arrows indicate the direction of circulation of the oil in the circuits 21, 31.

According to one variant, in a blade 11 or 12, the channels of the first circuit 21 and the channels of the second circuit 31 extend next to one another, being separated by a material thickness of between 1.0. mm and 10.0 mm (mm) to allow conductive heat exchange through the thickness of material between the hot fluid flowing in the channels of the first circuit 21 and the hot fluid flowing in the channels of the second circuit 31. This provision promotes the homogeneity of temperature on the surface of the blades. The thickness of material between the channels in a blade can be predicted to be constant, i.e. uniform over the extent of the channels. The blading area 10 may, for example, be constructed by a metal additive manufacturing process, equivalent to 3-D printing in a metallic material. The channels are thus directly created during the construction of the material block constituting the sector 10. Alternatively, the blading sector 10 can be constructed using more conventional manufacturing techniques. The two trays 16, 18 may for example each be formed by two machined plates 16A, 16B, 18A, 18B mounted on one another and bolted together or by any other suitable fastening means, as illustrated in FIG. 3. In this example, the two blades 11, 12 are integrally formed with the inner plates 16B, 18B of the two plates 16, 18, by machining a block at "0". The channels 24, 34, 26, 36 formed in the outer plate 18 and the inner plate 16 allow, when the turbomachine is operating, a heat exchange between the hot oil flowing in these channels and the cold air flow passing between them. blades 11 and 12. The channels 25, 35, 27, 37 formed in the blades 11, 12 allow, when the turbomachine is operating, a heat exchange between the hot oil flowing in these channels and the cold air flow which envelops each In the example of FIGS. 1 to 4, the first and second circuits 21, 31 are adjacent (ie extend side by side) in the blades 11, 12 but not in the inner tray 16 and outer 18. Thus, if we consider the inner plate 16, the second circuit 31 (ie the channels 36) extends in the space between the blades 11, 12, while that the first circuit 21 (ie the channels 24, 28) extends out of this gap, as shown in the IGS 2 and 4. FIGS. 5 and 6 show another example of blading sector 10 in which the first and second circuits 21, 31 are adjacent both in the blades 11, 12 and in the inner and outer plates 16 18. In addition, the fluid inlets 22, 32 and 23, 33 are arranged in such a way that: in the inner plate 16, the circumferential circulation direction of the hot fluid in the first circuit 21 is opposite to the direction circumferential circulation of the hot fluid in the second circuit 31, - in the first blade 11, the direction of radial circulation of the hot fluid in the first circuit 21 is opposite to the direction of radial circulation of the hot fluid in the second circuit 31, - in the outer plate 18, the circumferential circulation direction of the hot fluid in the first circuit 21 is opposite to the circumferential circulation direction of the hot fluid in the second circuit 31, 20 - in the second blade 12, the direction of radial circulation of the hot fluid in the first circuit 21 is opposite to the direction of radial circulation of the hot fluid in the second circuit 31. The circuits 21, 31 and the direction of circulation of the hot fluid in these circuits are shown schematically in FIG. 6. FIG 5 is a sectional view, similar to that of FIG 4, which shows the channels 29, 39, formed in the inner plate 16 and forming part of the circuits 21, 31. These channels 29 and 39 are adjacent (ie extend next to each other) while being separated by a seal 40. The path of the channels 29 and 39 is curvilinear so as to increase the distance traveled by the hot fluid 30 and, thus, increasing the heat exchange surface between the channels themselves as between each channel and the cold air flow which licks the surface of the inner plate 16 in the vein of the secondary flow. Channels 29, 39 may have different paths as in the example shown. As previously indicated, the circumferential circulation direction of the hot fluid in the channel 29 is opposite to the circumferential circulation direction of the hot fluid in the channel 39. For example, as illustrated by arrows in FIG. 5, the hot fluid flows from left to right in the channel 29 while the hot fluid circulates from right to left in the channel 39. A curvilinear path such as that of the channels 29, 39 may advantageously be adopted for the channels 26, 36 of the blading sector 10 in the embodiment corresponding to FIG 2, since this increases the heat exchange surface between each channel and the flow of cold air passing between the blades. FIG. 7 represents another example of a blading sector. This example comprises four circuits 21, 31, 41, 51 dedicated to the circulation of the hot fluid. These four circuits are adjacent in the blades 11, 12 and in the inner plates 16 and outer 18. In the blades, the direction of radial circulation of the hot fluid in two of these circuits 21, 51 is opposite to the direction of radial circulation of the fluid. in the other two circuits 31, 41. In the inner plate 16, between the blades 11, 12, the circumferential circulation direction of the hot fluid in the circuit 21 is opposite to the circumferential circulation direction of the hot fluid in the circuit 31. (The circuits 41, 51 do not pass in the inner plate 16 between the blades 11, 12). In the outer plate 18, between the blades 11, 12, the circumferential circulation direction of the hot fluid in the circuit 41 is opposite to the circumferential circulation direction of the hot fluid in the circuit 51 (the circuits 21, 31 do not pass into the outer plate 18, between the blades 11, 12).

Some or all of these modules may be used as heat exchangers. In particular, a vane-free vane module for circulating fluids in the vanes may be provided between two modules for heat exchange in the vanes. As illustrated in FIG. 8, a vane module (drawn in dashed line) without heat exchange by the vanes can be arranged in a circumferential space E between two modules. Such a bladder module may have no fluid circulation channel and therefore do not perform any heat exchange, or comprise fluid circulation channels but only in its inner and outer trays. It is also possible to have no bladder module in a circumferential space between two modules. In such a configuration, therefore, the entire circumferential extent of the blading 9 is not used for cooling. The heat exchanger modules may be evenly distributed around the rotational axis A of the turbojet rotor. The heat exchanger modules are, for example, of the same type as the vane sector 10 shown in FIG. 2. The vane sectors 10 of a vane 9 may be identical and dimensioned so as to obtain an even distribution. output straightening vanes about the axis A. Alternatively, the stator vane sector may comprise more than two vanes. For example, by repeating the diagram of the two-blade vane sector of FIG. 2, i.e. by continuing the circuits 21 and 31 so as to alternate for each circuit the passage in the outer plate and in the inner plate, one obtains an area of blade having an even number of blades. This has the advantage that the inlet and the outlet of the same hot fluid circuit are arranged on the same outer or inner plate. The fluid connection of two adjacent vane sectors is thus facilitated, the outlet of a hot fluid circuit on one sector being adjacent to the inlet of the similar hot fluid circuit on the adjacent vane sector. The stator blading sector may also include an odd number of blades greater than or equal to three.

FIGS. 9 and 10 show another example of blading sector 10. This example differs from that of FIG. 2 in that it comprises only one blade 11 extending between the inner and outer plates 16 18. This blading sector 10 is traversed by two oil circuits 21, 31, extending through the blade 11 and the plates 16, 18. In the blade 11, the radial flow directions of the Hot fluid in the two circuits 21, 31 are opposed, which makes it possible to homogenize the temperature on the surface of the blade 11. As shown in FIG. 10, the inner walls of the ducts of the two circuits 21, 31 form sharp angles so as to optimize the fluid passage section without compromising the rigidity of the blade and the ability of the blade to resist the impact of foreign bodies (ice, birds, etc.) that would strike its leading edge. The metal additive manufacturing processes are particularly suitable for the manufacture of blade sectors having such vanes provided with conduits of complex shapes. Furthermore, it is conceivable to circulate in the channels of fluid circuits of a blading sector not of the oil, but a coolant having a heating value greater than that of air or even that of 20. oil, on the one hand to allow improved heat exchange and on the other hand to ensure that there will be no oil loss if a blade sector was to be damaged to the point of breaking a channel of fluid. The cooling of the lubricating system oil of the turbomachine can be carried out in a heat transfer fluid / oil heat exchanger installed for example in the area between the fan casing and the nacelle hood. Since each heat transfer fluid circuit is independent of the oil circuit, the circulation of the coolant can be carried out by dedicated pumps. The modes or examples of embodiment described herein are given for illustrative and non-limiting purposes, a person skilled in the art can easily, in view of this presentation, modify these modes or examples of embodiment, or consider other while remaining within the scope of the invention. On the other hand, the term "comprising one" should be understood as being synonymous with "comprising at least one", unless the opposite is specified. Finally, the various features of the embodiments or examples of embodiments described in the present disclosure may be considered in isolation or may be combined with one another. When combined, these features may be as described above or differently, the invention not being limited to the specific combinations previously described. In particular, unless otherwise specified or technical incompatibility, a feature described in connection with a mode or example of embodiment may be applied in a similar manner to another embodiment or embodiment. 15

Claims (8)

REVENDICATIONS1. A turbomachine stator-blasting sector comprising at least one blade (11, 12), an outer plate (18) connected to the outer end of the blade, and an inner plate (16) connected to the end interior of the blade, in which: at least one first channel (25, 27) is formed in the blade (11, 12), the first channel and the blade being adapted to allow, when the turbomachine is operating, a heat exchange between a hot fluid circulating in the first channel and a cold air flow passing through the stator vane (9), - at least a second channel (35, 37) is formed in the vane (11, 12) , the second channel and the blade being adapted to allow, when the turbomachine is operating, a heat exchange between a hot fluid flowing in the second channel and a cold air flow passing through the stator vane, - the first and second channels (25, 27, 35, 37) are adjacent and belong respectively to first and second circuits (21, 31) which are tins having fluid inlets (22, 32) and fluid outlets (23, 33) such that the direction of radial circulation of the hot fluid in the first channel (25, 27) is opposite to the direction of radial circulation of the hot fluid in the second channel (35, 37). Blading sector according to claim 1, wherein the first and second circuits (21, 31) extend on the outer plate (18) and / or the inner plate (16) and are such that in this plate (16, 18), the circumferential circulation direction of the hot fluid in the first circuit (21) is opposite to the circumferential circulation direction of the hot fluid in the second circuit (31). 302 85 76 18 Blade sector according to claim 1 or 2, wherein at least one other channel is formed in the blade (11, 12), this other channel and the blade being adapted to allow, when the turbomachine is operating, a heat exchange between a hot fluid circulating in this other channel and a cold air flow passing through the stator vane, this other channel being adjacent to the first and second channels and belonging to another circuit (41, 51) distinct from the first and second circuits (21, 31). 4. Blade sector according to any one of claims 1 to 10 wherein the vanes (11, 12) are exit straightening vanes. The blading sector according to any one of claims 1 to 4, wherein the hot fluid is a liquid, particularly oil. 15 Blading sector according to any one of claims 1 to 5, wherein in at least one blade (11, 12) the first and second channels (25, 27, 35, 37) are separated from one another. other by a constant thickness of matter. 20 7. Turbomachine stator vanes comprising a plurality of vane modules each extending over an angular sector of the vane, the vane (9) being formed by connecting the modules end-to-end, in which at least one of the modules is formed by a blading sector (10) according to any one of claims 1 to 6. 25 8. Turbomachine comprising at least one blading sector (10) according to any one of claims 1 to 6. 30