Preheating module, furnace comprising such preheating module, and method for densifying and consolidating components by means of such preheating module

Abstract

The invention relates to a preheating module (10) comprising a dispersion chamber (11) and a diffusion chamber (12), the dispersion chamber comprising a unit (20) for distributing a gas mixture, the unit comprising an inlet (25) at a lower edge (17) and a plurality of inner walls (22) forming a flow path (21) for the gas mixture; the diffusion chamber is located downstream of and arranged above the dispersion chamber (11) and forms a stack together with the dispersion chamber. The flow path (21) of the gas mixture extends predominantly along a longitudinal axis (Y) and a transverse axis (Z) orthogonal to the stack axis (X), the dimension of the diffusion chamber (12) along the stack axis (X) differing by no more than 20% relative to the dimension of the dispersion chamber (11) along which stack axis.

Description

Technical Field

[0001] This invention relates to the technical field of preheating modules configured to be assembled in a furnace for densifying and consolidating components made of ceramic matrix composites (CMCs), particularly carbide-based ceramic matrix composites. The invention also relates to such furnaces. Finally, the invention relates to a method for densifying and / or consolidating components made of ceramic matrix composites using such a preheating module. Background Technology

[0002] This densification and / or consolidation method is used, for example, in the aerospace industry to manufacture components capable of withstanding high temperatures. It is particularly useful for components forming one or more turbines in an aircraft turbine, such as annular sections that define the outer periphery of turbine ducts.

[0003] Components made from carbide-based CMC materials can serve as an alternative to those made from metal alloys because they exhibit better mechanical properties and significantly lower density at high temperatures. To manufacture these components, a mixture of reactive gases is injected into a furnace, and as these gases decompose on the hot surface of the component, they form a ceramic coating whose composition can be controlled. Operationally, the ceramic layer is formed by densifying the component and subsequently consolidating it. These steps are typically achieved through chemical vapor infiltration.

[0004] Before being injected into the furnace and reaching the component, the gas mixture must be heated to prevent inhomogeneity and to avoid mismatch between the desired composition and the actual composition obtained. In this regard, the gas mixture must be prepared to ensure homogeneity, and it must also be heated to a suitable temperature to obtain a coating with the appropriate composition.

[0005] Figure 1a and Figure 1b A pit furnace 1 and a honeycomb furnace 1 are shown for consolidating and densifying components made of CMC material. Each furnace includes a processing module 2 in which consolidation and densification operations are performed on one or more components P, a depletion module 5 for capturing residual portions of the gas mixture and reaction byproducts, and a preheating module 10' for gradually bringing the gas mixture to the desired temperature in the processing module 2. For this purpose, each furnace 1 includes one or more syringes 4 carrying the reagent to be used. Thus, the reagent can be released into the furnace 1 via an inlet located at the lower edge 17' of the preheating module 10'. Figure 1a As shown, pit furnaces, which have a larger capacity than honeycomb furnaces, can advantageously include multiple crucibles 4.

[0006] The preheating module 10', processing module 2, and depletion module 5 are stacked in this order from the lower edge to the upper edge of the furnace. In other words, the preheating module 10' is upstream of the processing module 2, and the processing module 2 itself is upstream of the depletion module 5 along the stacking axis X of the preheating module 10', processing module 2, and depletion module 5. This stacking axis X also defines the main flow direction of the gas mixture. In this regard, the processing module 2 includes a cavity 3 for accommodating one or more components P. Figure 1a and Figure 1b As shown, the difference between a pit furnace and a honeycomb furnace is that a pit furnace includes a cavity 3, which typically comprises multiple stacked stages along the stacking axis X. Figure 1a In the example shown, cavity 3 comprises two stages. Figure 1b The cavity of the honeycomb furnace shown includes a single stage, but may include multiple stages.

[0007] Figure 2a A preheating module 10', known in the prior art, is shown more precisely. This preheating module 10' can be used in pit furnaces or honeycomb furnaces. According to the prior art, the preheating module 10' includes a dispersion chamber 11' for a gas mixture and a diffusion chamber 12' for the gas mixture, as shown in... Figure 2a This can be seen more clearly in the image. The diffusion chamber 12' is separated from the dispersion chamber 11' by a heat transfer cavity 30' comprising a plurality of vertically spaced horizontal walls. The dispersion chamber 11' includes an inlet 25' and one or more horizontal walls 22' at the lower edge 17' of the preheating module, the one or more horizontal walls being spaced along the stack axis X, and the one or more horizontal walls including a plurality of openings that allow the gas mixture to be dispersed. If the uniformity of the gas mixture is to be improved, the number of horizontal walls 22' must be increased. The diffusion chamber 12', which includes the heat transfer cavity 30', also includes a plurality of walls having openings that allow the gas mixture to be diffused.

[0008] Therefore, as the gas mixture flows within the preheating module 10' (including within the dispersion chamber 11'), it moves primarily vertically, i.e., from the lower edge 17' to the upper edge 18' of the preheating module, through the pathway formed by the openings. This movement of the gas mixture through the openings creates what are termed "baffles" for the gas mixture, providing a hot surface that allows it to gradually reach the desired temperature—the temperature at which the CMC material is desired to solidify and densify—through heat exchange with the wall surfaces. These exchanges are effective when the gas mixture diffuses laterally to the convective flow, and are advantageous when the gas mixture moves at low speeds and flow rates. The flow is typically laminar.

[0009] In other words, in this type of furnace, the preheating module 10' occupies a relatively large volume. Typically, the volume of the preheating module is about 20% of the stacked volume. This is due to the corresponding dimensions of the dispersion chamber 11' and the diffusion chamber 12' in the stacking direction. The diffusion chamber 12', which includes the heat transfer cavity 30', also includes multiple walls with openings that allow the gas mixture to diffuse. Therefore, the diffusion chamber 12' can be three times larger than the dispersion chamber 11' along the stack axis. In pit furnaces, this is acceptable, as long as the components can be loaded on different stages. However, manufacturers must adjust the furnace, particularly reducing its size (especially along the stack axis), so that these furnaces can be more easily integrated into pre-existing production lines. It is in this context that the aforementioned honeycomb furnace was developed.

[0010] The present invention aims to overcome at least some of the problems mentioned above and proposes a preheating module for a furnace for consolidating and densifying components made of CMC material, the preheating module having a reduced size in the main movement direction of the gas mixture, and still enabling improved gas mixing despite the reduced size.

[0011] Documents US 2017 / 002466 A1, US 6 572 371 B1, US 5 480 678 A, US 2007 / 275339A1, and CN 109 400 198 A disclose preheating modules for furnaces. However, none of these documents address the aforementioned problems, particularly improving gas mixing within the preheating module (despite its reduced size). Summary of the Invention

[0012] To this end, a preheating module for a furnace is provided, comprising a dispersion chamber and a diffusion chamber, the diffusion chamber being disposed above the dispersion chamber and stacked with the dispersion chamber along a stacking axis, the preheating module being configured to be traversed by a gas mixture moving along the stacking axis from the lower edge of the preheating module toward the upper edge of the preheating module, the dispersion chamber comprising a gas mixture inlet unit including an inlet located at the lower edge and a plurality of inner walls forming a flow path for the gas mixture, the diffusion chamber of the gas mixture being located downstream of the dispersion chamber along the flow direction of the gas mixture and including a heat transfer wall separating the diffusion chamber from the dispersion chamber, the flow path of the gas mixture extending primarily in directions of a longitudinal axis and a transverse axis orthogonal to the stacking axis, the dimension of the diffusion chamber along the stacking axis differing from the dimension of the dispersion chamber along the stacking axis by no more than 20%.

[0013] The preheating module is characterized in that each inner wall includes a plurality of fins extending from at least one surface of the inner wall, each fin forming an opening angle with the associated inner wall along the main flow direction of the gas mixture within the inrush unit.

[0014] Therefore, unlike known preheating modules, the preheating module according to the present invention has a significantly reduced size along the stack axis. In fact, when the gas mixture enters the inrush unit and flows through the flow path, the gas mixture can flow primarily in the directions of the longitudinal and transverse axes, thus orthogonal to the main direction of movement. In other words, the main element of the gas mixture's displacement is the displacement element along the longitudinal and transverse axes. The dispersion of the gas mixture occurs primarily orthogonally to the stack axis rather than along it. This significantly reduces the size of the dispersion chamber along the stack axis.

[0015] In addition to reducing the size of the dispersion chamber, the size of the diffusion chamber can also be reduced. Since the dispersion chamber includes multiple inner walls, a significant amount of heat exchange occurs within it, increasing the heat exchange potential of the gas mixture in the dispersion chamber compared to prior art furnaces. Furthermore, the surface area required for heat exchange along the stack axis can be reduced, thereby reducing the heat transfer cavity to a simple heat transfer wall. As previously mentioned, prior art preheating modules include a cavity for providing contact surfaces for heat exchange, separating the dispersion chamber and the diffusion chamber. This cavity includes multiple horizontal walls spaced apart from each other, increasing the size of the preheating module along the stack axis. In this way, the diffusion chamber can have a size along the stack axis comparable to that of the dispersion chamber.

[0016] The fins further improve the mixing of the gas injected into the inrush unit. Each of these fins forms an opening angle with the associated inner wall along the main flow direction, allowing the gas mixture to maintain an appropriate flow rate within the inrush unit while improving the mixing process.

[0017] The following are the features according to the present invention that can be used together or individually: - The ratio between the length of the flow path and the dimension of the preheating module along the longitudinal and / or transverse axes is between 4 and 150; - The inner walls are separated from each other by a distance between 20mm and 100mm; - The bursting unit includes at least one stage defined by a first outer peripheral wall and a second outer peripheral wall along the stacking axis, and an inner wall extending orthogonally to the first outer peripheral wall and the second outer peripheral wall between the first outer peripheral wall and the second outer peripheral wall. - The preheating module includes at least one sidewall extending about the stack axis, the sidewall including at least two radially opposite portions, and wherein a first series of inner walls extends from a first portion of the sidewall, a second series of inner walls extends from a second portion of the sidewall, the first series of inner walls and the second series of inner walls are arranged parallel to each other and alternate one after the other. -The inner wall includes two walls located distal to the center of the first outer peripheral wall, and the distal wall includes a plurality of openings; -The inner wall is arranged in a spiral shape; - The third series of inner walls extends from the first outer peripheral wall, and the fourth series of inner walls extends from the second outer peripheral wall. The third series of inner walls and the fourth series of inner walls are arranged parallel to each other and alternate one after another. - The heat transfer wall includes a plurality of first openings, the plurality of first openings occupying 20% ​​to 35% of the total surface area of ​​the heat transfer wall, excluding end values; - The diffusion chamber includes multiple diffusion walls, each diffusion wall including a second opening, the second opening occupying 35% to 50% of the total area of ​​the diffusion wall, preferably occupying 40% to 60% of the total surface area of ​​the diffusion wall.

[0018] The present invention also relates to a furnace for consolidating and densifying components made of ceramic matrix composites, the furnace including a processing module and a preheating module as described above, the processing module including a cavity for receiving the component, the preheating module being located below the processing module and forming a second stack with the processing module along a stacking axis.

[0019] The present invention also relates to a method for consolidating and densifying ceramic matrix composite components, the method being carried out in a furnace as described above, the method comprising the following steps in sequence: Step 110) Provide the furnace as described above. Step 120) Wait for the temperature in the inrush unit to reach a value between 100°C and 200°C lower than the desired temperature in the processing module, and for the temperature in the diffusion chamber to reach a value between 30°C and 5°C lower than the desired temperature in the processing module. In step 130) simultaneously with or after step 120), the gas mixture is injected into the furnace and the process is allowed to proceed until the gas mixture reaches the desired temperature. Attached Figure Description

[0020] Other objects, features, and advantages of the present invention will become clearer from the following description with reference to the accompanying drawings, in which: - Figure 1a This is a schematic cross-sectional view of a pit furnace. - Figure 1b This is a schematic cross-sectional view of a honeycomb furnace. - Figure 2a This is a schematic cross-sectional view of a preheating module known in the prior art. - Figure 2b This is a schematic cross-sectional view of a preheating module according to an embodiment of the present invention. - Figure 2c This is a schematic cross-sectional view of the preheating module according to the present invention. - Figure 3This is a schematic top view of a first example of a flow unit for a preheating module according to an embodiment of the present invention. - Figure 4 This is a schematic top view of a second example of a jetting unit for a preheating module according to the present invention. - Figure 5 This is a schematic top view of a third example of a jetting unit for a preheating module according to the present invention. - Figure 6 This is a schematic cross-sectional view of a fourth example of a jetting unit for a preheating module according to the present invention. - Figure 7 This is a schematic diagram of a method for consolidating and densifying components made of CMC material according to the present invention. Detailed Implementation

[0021] In this specification, the terms "upper" and "lower" should not be construed as limiting, but are merely used to provide a better understanding of the invention with reference to the accompanying drawings. The use of the term "lower" simply indicates that the element under discussion is closer to the lower edge than the element associated with the term "upper," such as a furnace. For example, "lower edge of the preheating module" refers to the portion of the preheating module closer to the lower edge of the furnace according to the invention.

[0022] When the term "upstream" is used to indicate that the first element is located "upstream" of the second element, it means that the first element is located ahead of the second element in the direction or path of flow of the gas mixture. Similarly, when the term "downstream" is used to describe the positioning of one element relative to another, it means that the first element in question is located behind the other element in the direction or path of flow of the gas mixture.

[0023] refer to Figure 1a , Figure 1b and Figure 2b This invention relates to a furnace 1 for consolidating and densifying a component P made of a ceramic matrix composite material. Figure 1a and Figure 1b The furnaces shown in the figure and described above in this specification are, respectively, a pit furnace and a honeycomb furnace. The preheating module 10 (which is also the subject of this invention) will be described below; the preheating module is equally suitable for pit furnaces (e.g., Figure 1a The well-type furnace shown) and the honeycomb furnace (e.g.) Figure 1b (The honeycomb furnace shown). The preheating module 10 is also applicable to other types of furnaces not mentioned in this specification for the consolidation and densification of components made of CMC material. Preferably, the furnace can be evacuated.

[0024] Before describing the preheating module 10 in more detail, and as described above, the furnace includes a processing module 2 in which consolidation and densification operations are performed on one or more components P, a depletion module 5 for capturing residual portions of the gas mixture and reaction byproducts, and a preheating module 10 for gradually bringing the gas mixture to the desired temperature in the processing module 2.

[0025] The preheating module 10, processing module 2, and depletion module 5 are stacked in this order from the lower edge to the upper edge of the furnace 1. In other words, starting from the lower edge of the furnace 1, the preheating module 10 is located below the processing module 2, and the processing module itself is located below the depletion module 5. More precisely, the gas mixture flows from the lower edge 17 of the preheating module to the upper edge 18 of the preheating module and passes through different areas of the preheating module 10.

[0026] The gas mixture consists of a variety of reactive gases. The reactivity of the gases can be caused by a variety of factors known to those skilled in the art. For example, the reactivity of the gases can be enhanced by heating these gases within the preheating module 10 to a specific temperature. In the context of this invention, the gas mixture is not limited to a particular type of precursor. All you need to do is select a suitable gas mixture for the application. In one application of this invention, component P is made of a carbide-based ceramic matrix composite material. For example, component P can be made of silicon carbide (SiC), boron nitride (BN), carbon, or SiBN. In all cases, a suitable reactive gas should be used to consolidate and densify the component with the material used to manufacture it.

[0027] The preheating module 10 according to the invention includes a dispersion chamber 11 and a diffusion chamber 12, the diffusion chamber being arranged above the dispersion chamber 11 and stacked with the dispersion chamber 11 along a stacking axis X. This stacking axis X also defines the main flow direction of the gas mixture in the furnace 1 and the stacking axis of the preheating module, the processing module 2, and the depletion module 5. The diffusion chamber 12 is located downstream of the dispersion chamber 11 along the flow direction of the gas mixture. The diffusion chamber 12 includes a heat transfer wall 30 that separates the diffusion chamber from the dispersion chamber 11. This will be described in more detail later.

[0028] The function of the dispersion chamber 11 is to disperse the gas, allowing it to be mixed for the first time. Therefore, the gas does not necessarily enter the dispersion chamber 11 as a gas mixture, and can be mixed only within the dispersion chamber 11. Another function of the dispersion chamber 11 is to homogenize the gas mixture. This improves the heating of the gas mixture, i.e., makes it easier for the gas mixture to reach a certain temperature. Therefore, when leaving the dispersion chamber 11, the gas is not only in the form of a mixture, but also in the form of a homogeneous mixture. For this purpose, the dispersion chamber 11 includes a gas mixture inlet unit 20 for mixing and homogenizing the gas.

[0029] The inlet unit 20 is equipped with an inlet 25 located at the lower edge 17 of the preheating module. Gas or gas mixture (as the case may be) enters the furnace 1 according to the invention via the inlet 25. As previously described, the furnace 1 includes one or more injectors 4 containing reagents required for methods of consolidation and densification of components. The reagents are typically supplied to the furnace in gaseous form at room temperature. More precisely, the reagents are injected into the inlet unit 20 via the inlet 25, thereby ensuring uniform mixing of the reagents.

[0030] exist Figure 2b In the example of the illustrated embodiment, inlet 25 is constituted by a single opening formed in the lower edge 17 of the preheating module. However, inlet 25 may be formed by multiple openings. In the context of this invention, the number, shape, and size of the openings are not limiting. Nevertheless, as will be seen later, preferably, the size of one or more openings forming inlet 25 is selected such that the reagent can enter the inlet unit 20 at a velocity between 0.1 m / s and 10 m / s, preferably between 0.1 m / s and 2 m / s. This allows the gas mixture to have appropriate kinematic dynamics within the inlet unit 20.

[0031] The flow unit 20 includes a plurality of inner walls 22 forming flow paths 21 for the gas mixture. Flow paths 21 are passages formed in the flow unit 20 that allow the gas mixture to be guided from the inlet 25 of the flow unit to the outlet 26 of the flow unit. Thus, path 21 marks the path of the gas mixture as it flows through the flow unit 20. In addition to these considerations, path 21 is configured to disperse the gas mixture as it flows through the flow unit 20, which will be discussed in more detail later.

[0032] exist Figure 2b In the example of the embodiment shown, the flow unit 20 includes a stage 20a defined by a first outer peripheral wall 23 and a second outer peripheral wall 24 along the stacking axis X, with an inner wall 22 extending between the first and second outer peripheral walls. However, the flow unit 20 may also include multiple stages 20a, 20b... as shown. Figure 2c As shown, multiple stages are positioned one after another along the stacking axis X. In this configuration, the flow unit 20 includes intermediate walls 23i between each stage 20a, 20b, etc., and the intermediate walls form the physical boundaries between each stage.

[0033] Preferably, the intermediate wall 23i has the same longitudinal and transverse dimensions as the first outer peripheral wall 23 and the second outer peripheral wall 24. Also preferably, the configuration (i.e., arrangement) of the inner wall 22 is the same from one stage to the next. This simplifies the method of manufacturing the preheating module 10. However, this is not mandatory. Furthermore, preferably, the number of stages in the flow unit 20 does not exceed two, which provides a good trade-off between obtaining a sufficiently uniform gas mixture and the height of the preheating module 10, which is the dimension of the preheating module along the stack axis X. Preferably, each stage maintains a height of at least 20 mm so that the gas mixture can flow sufficiently in the path 21 while promoting heat exchange.

[0034] In the example of the illustrated embodiment, the distal inner wall 22 is continuous, i.e., the distal inner wall does not include an opening. The gas mixture passes from one stage to the next through an opening 22f located near the end of the intermediate wall 23i. Thus, the gas mixture passes almost the entire upstream stage (i.e., the lower stage) before reaching the downstream stage (upper stage). Furthermore, the gas mixture can exit the upper layer only through an opening 24a, which is located distally relative to the opening 22f in the lower layer. In the example of the illustrated embodiment, the distal opening 24a is formed at the center of the second outer peripheral wall 24, which allows the mixture to return along the path 21 of the upper stage before exiting the inrush unit 20.

[0035] like Figure 2b As shown, it is advantageous to leave a passage between stage 20a and heat transfer wall 30, allowing the gas mixture to reach the diffusion chamber 12 from the inrush unit 20. When the inrush unit 20 includes multiple stages 20a, 20b, etc., a sufficient gap should be maintained along the stack axis X between the last stage and the heat transfer wall 30, the last stage being the downstream stage of the inrush unit 20 in the gas flow direction. Preferably, the distance between the last stage of the inrush unit 20 and the heat transfer wall 30 along the stack axis X is greater than or equal to 20 mm.

[0036] According to the invention, the flow path 21 for the gas mixture extends primarily in the directions of the longitudinal axis Y and the transverse axis Z, which are orthogonal to the stacking axis X. This allows for... Figures 3 to 5 It is clearer in the middle that Figures 3 to 5 A top cross-sectional view of the interior of the inrush unit 20, an alternative embodiment of the preheating module 10 according to the invention, is shown. In these various embodiments, which will be described in more detail below, the inner wall 22 is arranged such that the flow path 21 for the gas mixture extends primarily orthogonally to the stack axis X.

[0037] As a result, the gas mixture forced to follow path 21 flows primarily in a direction orthogonal to the stacking axis X. In other words, the main elements of the three-dimensional displacement of the gas mixture are defined along the longitudinal axis Y and the transverse axis Z. Under these conditions, the "horizontal" volume of the flow unit 20 is primarily used for mixing and homogenizing the gas mixture, rather than its "vertical" volume. To improve gas dispersion and homogenization, the number of inner walls 22 can be increased along the longitudinal axis Y or the transverse axis Z, rather than increasing the number of walls along the stacking axis X. Better results can also be obtained in terms of mixing and homogenizing the gas mixture compared to the prior art, because the path 21 to be traversed can be significantly lengthened, and this does not adversely affect the size of the preheating module 10, nor subsequently the size of the furnace 1 along the stacking axis X. Because the gas is mixed better and more uniformly, the gas mixture can be heated faster than in prior art furnaces.

[0038] Similarly, according to the invention, the dimension of the diffusion chamber 12 along the stacking axis X differs from the dimension of the dispersion chamber 11 along the stacking axis by no more than 20%. In fact, the dimension of the diffusion chamber 12 along the stacking axis X can be significantly reduced, thus allowing the gas mixture to be heated more quickly, as previously mentioned. A direct result is a reduction in the useful surface area for heating the gas mixture. Therefore, the diffusion chamber 12 can have far fewer walls in both the heat transfer region (heat transfer wall 30) and the diffusion region (diffusion wall 35). Thus, in the invention, the heat transfer region can be reduced to the heat transfer wall 30, rather than a heat transfer cavity 30' comprising multiple heat transfer walls. Therefore, the dimension of the diffusion chamber 12 can be divided by 3 compared to the dimensions of the diffusion chamber 12' known in the prior art.

[0039] Advantageously, the ratio between the length of the flow path 21 and the dimensions of the preheating module (along the longitudinal axis Y and / or the transverse axis Z) is between 4 and 150. The "length of path 21" is defined as the distance the flow path 21 extends, taking into account any tortuosity. "Tortuosity" refers to various directional changes made by the flow path 21 without any discontinuities (i.e., interruptions) within it. The appropriate length of the flow path 21 depends on the dimensions of the preheating module 10; therefore, the length of path 21 must be adapted to the dimensions of the preheating module.

[0040] Within this range of values, the gas mixture is forced to undergo at least one directional change as it moves within the inrush unit 20. In fact, within this range of values, the gas mixture undergoes multiple directional changes as it flows through the inrush unit 20, which increases the residence time of the gas mixture within the inrush unit 20, thus being more conducive to gas mixing. Furthermore, the longer the residence time of the gas mixture in the inrush unit 20, the more uniform the resulting gas mixture. For example, if the quantity and properties of the reagent demonstrate this, a longer path 21 should be selected considering the overall size of the preheating module 10. Therefore, those skilled in the art will adjust the length of path 21 according to these parameters.

[0041] Homogenization of the gas mixture can continue at the outlet of the inrush unit 20. In this regard, the distal inner wall 22 relative to the inlet 25 may include a plurality of openings 22e. The openings 22e are used to control the pressure drop at the outlet of the inrush unit 20. Figure 2b A cross-sectional view of one of these openings 22e is shown. The distal inner wall 22 is the inner wall furthest from the inlet 25 through which the gas mixture enters the inlet unit 20. Figure 2b In the example of the illustrated embodiment, these distal inner walls 22 are the outer inner walls 22 relative to the center position of the inlet 25. However, the inlet 25 does not necessarily occupy the center position in the preheating module 10, and similarly, the distal inner walls 22 are not necessarily the outer inner walls 22.

[0042] like Figure 2b As shown, the inner wall 22 extends orthogonally to the first outer peripheral wall 23 and the second outer peripheral wall 24 between them. Unlike the horizontal wall 22' of the dispersion chamber 11' known in the prior art, the inner wall 22 of the inrush unit 20 extends vertically over the entire height of the inrush unit stage 20a. Note that the height of the stage 20a corresponds to the distance between the first outer peripheral wall 23 and the second outer peripheral wall 24.

[0043] When there exists such Figure 2c When multiple stages 20a, 20b, etc., are shown, it is important that at each stage, the inner wall 22 extends between the walls defining that stage. This could be between the first outer peripheral wall 23 and one of the multiple intermediate walls 23i, or between two intermediate walls 23i, or between one of the multiple intermediate walls 23i and the second outer peripheral wall 24. Furthermore, as can be clearly understood, when the distal inner wall relative to the entrance is perforated (i.e., includes multiple openings 22e), this refers to the inner walls 22 other than the distal inner walls 22, since these distal inner walls 22 do not inherently extend over the entire height of stage 20a or each stage.

[0044] As described above, the fact that the inner wall 22 extends across the entire height of the inrush unit 20 facilitates laminar flow, in which shear stress is applied by the tortuosity of the path 21. In this way, the mixing and homogenization of the gas mixture can be modulated by the length of the path 21 and the length of the path applied to the gas mixture by the path 21, and depends almost (if at all) not on the surface properties of the inner wall 22 itself. In other words, the continuity of the inner wall 22 along the height of stage 20a means that the flow dynamics of the gas mixture in the inrush unit 20 can be controlled by the tortuosity of the path 21. Similarly, the surface roughness and texture of these inner walls 22 can also play a role in this flow dynamics. In this particular case, the flow dynamics depend almost entirely on the surface roughness or texture because, given the tortuosity of the path 21, the phenomena occurring at the macroscopic level are dominant.

[0045] In this regard, according to one aspect of the invention, each inner wall includes a plurality of fins 27 extending from at least one surface of the inner wall. For example, in Figure 4 These fins can be seen in the image. The fins further improve the mixing of the gas injected into the inrush unit 20. The fins 27 are in the form of protrusions extending obliquely from the surface of the inner wall 22. More precisely, each fin 27 forms an opening angle with the inner wall 22 associated with it along the main flow direction of the gas mixture within the inrush unit 20.

[0046] Each of these fins forms an opening angle with the associated inner wall along the main flow direction, allowing the gas mixture to maintain an appropriate flow velocity within the inrush unit while improving the mixing process. Too low a flow velocity would increase preheating time, which would affect the duration of the densification and consolidation methods implemented with furnace 1. If the flow velocity is too high, sufficient heat exchange will not be possible, and therefore the desired temperature will not be reached at the outlet of preheating module 10. Therefore, the presence of fins 27 and their corresponding positioning relative to the inner wall (i.e., having an opening angle in the main flow direction) allows for a trade-off between the mixture flow velocity and improved gas mixing. It should be noted that gas mixing is improved at this stage because the mixing process leads to better homogenization of the gases in the mixture.

[0047] like Figure 4 As shown, the fins 27 may extend from both surfaces of the inner wall 22, or from only one surface of the inner wall 22. This choice is made from the outset when designing the preheating module 10 according to the invention based on dimensional constraints (particularly along the longitudinal axis Y and / or along the transverse axis X) for the purpose of manufacturing the preheating module.

[0048] It should be noted that when referring to the surfaces of the inner wall 22, as in the above case, it refers to the two large surfaces of the inner wall 22. These surfaces are "large" compared to the four side surfaces of the inner wall 22, each having at least one dimension smaller than the other surfaces (this dimension specifically corresponds to the thickness of the relevant inner wall 22). Unlike the four side surfaces, the large surfaces are directly swept by the gas mixture.

[0049] Preferably, the inner walls 22 are separated from each other by a distance or gap between 20 mm and 100 mm, which ensures sufficient heat exchange surface between the gas mixture and the solid surface of the inner walls 22. These distances can vary depending on the overall dimensions of the preheating module. Too small a gap may cause premature blockage of the path 21 and may result in a pressure drop. In this case, it may be difficult to achieve the appropriate pressure in the furnace 1. If the gap is too wide, the efficiency of heat exchange between the gas mixture and the inner walls 22 becomes lower. Preferably, the inner walls 22 are separated from each other by a distance between 40 mm and 60 mm, which represents a good trade-off between the risk of blockage of the path 21 and the efficiency of heat exchange.

[0050] For the same reason, the first outer peripheral wall 23 and the second outer peripheral wall 24 are preferably separated by a distance di between 20 mm and 100 mm, more preferably between 40 mm and 60 mm.

[0051] The following paragraphs describe different versions of embodiments of the inrush unit 20. These variations of the embodiments are merely examples, and the invention is in no way limited to the configurations shown.

[0052] First, regarding Figures 2b to 6 In the illustrated embodiment, it should be noted that the preheating module 10 includes at least one sidewall 13 extending around the main axis X, which preferably includes at least two radially opposing portions 13a, 13b. In the illustrated embodiment, the sidewall 13 has a parallelepiped shape when viewed in cross-section. However, this is not mandatory, and the sidewall 13 can have any other cross-sectional shape, such as a circular cross-section. Regardless of the shape chosen, and as stated above, the wall may preferably include at least a first portion 13a and a second portion 13b radially opposite to the first portion 13b.

[0053] according to Figure 3In a first variation of the illustrated embodiment, a first series of inner walls 22a extends from a first portion 13a of the sidewall, and a second series of inner walls 22b extends from a second portion 13b of the sidewall. The first series of inner walls 22a and the second series of inner walls 22b are arranged parallel to each other, alternating one after the other. In other words, the first series of inner walls 22a and the second series of inner walls 22b are parallel and arranged such that the inner wall of one series is inserted between two consecutive inner walls of another series, except, obviously, the distal inner wall 22. In the illustrated example, each series comprises a total of four inner walls 22a, 22b. This forms a path 21 in which generally U-shaped semi-loops follow one another. This configuration produces a path 21 that is both compact and conducive to heat exchange.

[0054] Figure 4 The shown burst unit 20 and Figure 3 The essential difference in the flow unit shown is only that the inner wall 22 includes fins 27, which, as previously mentioned, further facilitate heat exchange. Also... Figure 3 and Figure 4 As shown, the inlet 25 occupies a roughly central position on the first outer peripheral wall 23, such that the first series of inner walls 22a and the second series of inner walls 22b are arranged on either side of the inlet. In this configuration, there are actually two paths 21 in which the gas mixture flows along the same path but in opposite longitudinal and transverse directions.

[0055] according to Figure 5 In a second variation of the illustrated embodiment, the inner wall 22 is arranged in a spiral or labyrinthine shape. This configuration has the advantage of providing a longer path 21 compared to the configuration seen in the first variation of the reference embodiment. This is because less space is lost around the central region of the first outer peripheral wall 23, which in this embodiment is occupied by the outlet 26 of the inrush unit 20. Thus, the gas mixture travels a longer distance, which further facilitates mixing and homogenization of the gas between the inlet 25 and the outlet 26. In this embodiment, the inlet 25 is located at one end of the inrush unit 20, and as described above, the outlet 26 occupies the central position. This makes it easier to achieve the labyrinthine profile of the path 21.

[0056] according to Figure 6 In the third embodiment shown, the third series of inner walls 22c extends from the first outer peripheral wall 23, and the fourth series of inner walls 22d extends from the second outer peripheral wall 24. The first series of inner walls 22c and the second series of inner walls 22d are arranged parallel to each other and alternate one after the other. The only difference between this structure and the structure seen in the first variant is that the inner walls 22 do not extend from the first portion 13a and the second portion 13b of the sidewalls, but rather from the first outer peripheral wall 23 and the second outer peripheral wall 24.

[0057] Therefore, the inner walls 22c of the third series and 22d of the fourth series are parallel and arranged such that, except for the distal inner wall 22, the inner wall of one of these series is inserted between two consecutive inner walls of the other series. In the example shown, each series comprises a total of eight inner walls 22a, 22b. This forms path 21, in which roughly U-shaped semi-rings follow one another. This configuration produces path 21 that is both compact and conducive to heat exchange.

[0058] According to a particularly advantageous embodiment, the ratio between the surface area formed by the inner wall 22, the outer peripheral walls 23, 24, and, where applicable, the intermediate wall 23i, and the volume of the inrush unit 20, is between 3.1 and 3.3. It should be noted that at this stage, in the dispersion chamber 11' known in the prior art, this ratio is between 3 and 4. This provides a very high level of efficiency for the inrush unit 20, and more generally for the furnace 1. This is because the ratio between the heat exchange surface and the total volume of the preheating zone is relatively low. In a smaller volume, heat exchange is maintained at an appropriate level, or even higher. Depending on the design approach used, this ratio can be even lower.

[0059] As the gas mixture leaves the inrush unit 20, heat exchange should advantageously continue effectively with the heat transfer wall 30. In this regard, the heat transfer wall 30 includes a plurality of first openings 31 occupying 20% ​​to 35% (excluding endpoints) of its total surface area. Thus, the heat transfer wall 30 allows the mixture to continue its journey to the diffusion chamber 12 while still having sufficient effective surface area to perform heat exchange with the gas mixture. As will be seen later, the temperature difference between the heat transfer wall 30 and the desired temperature in the processing module 2 is smaller than the temperature difference between the inrush unit 20 and the desired temperature in the processing module 2.

[0060] Advantageously, in this respect, the diffusion chamber 12 may include a plurality of diffusion walls 35, each diffusion wall 35 including a second opening 36, the second opening occupying 35% to 50% of the total surface area of ​​the diffusion wall 35, preferably between 40% and 60% of the total surface area of ​​the diffusion wall 35. Therefore, when the gas mixture arrives at the diffusion chamber 12, the gas mixture can be uniformly diffused into the processing module 2.

[0061] The present invention also relates to a method 100 for consolidating and densifying a ceramic matrix composite component P, which is carried out via a furnace as described above. Before describing the method in more detail, the following paragraphs describe the temperature ranges to which various parts of the preheating module 10 are exposed. However, it should be noted that the temperature will depend on the method implemented and the type of furnace used. Therefore, the following paragraphs are merely a guide to achieving the desired temperature at the outlet of the preheating module 10.

[0062] Preferably, the dispersion chamber 11 is furthest from the processing module 2. The dispersion chamber has a temperature between 30°C and 200°C lower than the desired temperature in the processing module 2. More specifically, the inrush unit 20 has a temperature between 100°C and 200°C lower than the desired temperature in the processing module 2.

[0063] The heat transfer wall 30 can advantageously have a temperature 30°C lower than the desired temperature in the processing module 2. Preferably, the diffusion chamber 12 has a temperature between 30°C (at the heat transfer wall 30 of the diffusion chamber) and 5°C (at the upper edge 18 of the preheating module 10) lower than the desired temperature in the processing module 2. In this way, the area in the processing module 2 where the object is located can reach the desired temperature. The 5°C difference with the upper edge 18 of the preheating module is directly compensated for at the lower part of the processing module.

[0064] Reference Figure 7 Method 100 includes a first step 110, which includes providing a furnace 1 as described above. Preferably, a component P made of CMC material is simultaneously arranged in the processing module 2 of the furnace.

[0065] Method 100 includes a second step 120), which includes two sub-steps 122) and 124. In the first sub-step 122), the temperature T in the inrush unit 20 is awaited. UE Reaching the desired temperature T relative to processing module 2 MC The temperature is between 100°C and 200°C. Cold gas is supplied to the preheating module, and then the cold gas is heated in the preheating module 10. In the second sub-step 124), the temperature T in the diffusion chamber 12 is made to be lower than that of the preheating module 10. CD Reaching the desired temperature T relative to processing module 2 MC The value is between 30°C and 5°C. The first sub-step 122) and the second sub-step 124) can be performed simultaneously. The second step 120) can advantageously be performed by a control module (not shown) for controlling the furnace 1 according to the invention. In this regard, the control module can be equipped with a processor that includes instructions for performing the second step 120).

[0066] Method 100 includes a third step 130), which can be performed simultaneously with or after the second step 120. During this third step 130, the gas mixture is injected into furnace 1 and the process is continued until the gas mixture reaches the desired temperature T. MCThe temperature is achieved via the preheating module 10 as described above. For this purpose, the gas mixture continuously passes from the preheating module 10 to the processing module 2. Within the preheating module 10, the gas mixture passes through the inrush unit 20, the dispersion chamber 11 (the area outside the inrush unit), the heat transfer wall 30, and the diffusion chamber 12 in the following order. As seen above, the gas mixture undergoes multiple heat exchanges with the surface of the inner wall 22 of the inrush unit 20 and subsequently with the heat transfer wall 30, which allows the desired temperature to be reached by extending the path of the gas mixture. Of course, if the inrush unit 20 comprises multiple stages 20a, 20b, etc., the gas mixture passes through each stage before leaving the inrush unit 20. Advantageously, the size of one or more openings forming the inlet 25 is selected such that the reagent can enter the inrush unit 20 at a velocity between 0.1 m / s and 10 m / s, preferably between 0.1 m / s and 2 m / s.

[0067] Therefore, in the fourth step (140), once the gas mixture reaches the desired temperature in the processing module 2, the component is solidified. The duration of this stage depends on the method to be implemented and the selected pressure and temperature parameters. In the fifth step (150), the component is densified. Similar to the solidification step (140), the duration of this fifth step depends on the method to be implemented and the selected pressure and temperature parameters.

Claims

1. A preheating module (10) for a furnace (1), the preheating module (10) comprising a dispersion chamber (11) and a diffusion chamber (12), the diffusion chamber being disposed above the dispersion chamber (11) and stacked with the dispersion chamber (11) along a stacking axis (X), the preheating module (10) being configured to be traversed by a gas mixture moving along the stacking axis (X) from a lower edge (17) of the preheating module toward an upper edge (18) of the preheating module, the dispersion chamber (11) comprising a gas mixture inlet unit (20), the gas mixture inlet unit comprising an inlet located at the lower edge (17). The gas mixture includes an inlet (25) and multiple inner walls (22) forming a flow path (21) for the gas mixture. The diffusion chamber (12) of the gas mixture is located downstream of the dispersion chamber (11) along the flow direction of the gas mixture and includes a heat transfer wall (30) separating the diffusion chamber (12) from the dispersion chamber (11). The flow path (21) of the gas mixture extends primarily in the directions of the longitudinal axis (Y) and the transverse axis (Z) orthogonal to the stack axis (X). The dimension of the diffusion chamber (12) along the stack axis (X) differs from the dimension of the dispersion chamber (11) along the stack axis by no more than 20%. The preheating module (10) is characterized in that each inner wall (22) includes a plurality of fins (27) extending from at least one surface of the inner wall (22), each fin (27) forming an opening angle with the associated inner wall (22) along the main flow direction of the gas mixture within the inrush unit (20).

2. The preheating module (10) according to claim 1, wherein, The ratio between the length of the flow path (21) and the dimension of the preheating module along the longitudinal axis (Y) and / or the transverse axis (Z) is between 4 and 150.

3. The preheating module (10) according to any one of the preceding claims, wherein, The inner walls (22) are separated from each other by a distance between 20 mm and 100 mm.

4. The preheating module (10) according to any one of claims 1 to 3, wherein, The bursting unit (20) includes at least one stage (20a) defined by a first outer peripheral wall (23) and a second outer peripheral wall (24) along the stacking axis (X), and the inner wall (22) extends orthogonally to the first outer peripheral wall (23) and the second outer peripheral wall (24) between the first outer peripheral wall (23) and the second outer peripheral wall (24).

5. The preheating module (10) according to claim 4, wherein, The preheating module (10) includes at least one sidewall (13) extending around the stack axis (X), the sidewall (13) including at least two radially opposite portions (13a, 13b), wherein a first series of inner walls (22a) extends from the first portion (13a) of the sidewall and a second series of inner walls (22b) extends from the second portion (13b) of the sidewall, the first series of inner walls (22a) and the second series of inner walls (22b) being arranged parallel to each other and alternating one after the other.

6. The preheating module (10) according to claim 5, wherein, The inner wall (22) includes two walls located distal to the center of the first outer peripheral wall (23), and the distal wall includes a plurality of openings (22e).

7. The preheating module (10) according to claim 4, wherein, The inner wall (22) is arranged in a spiral shape.

8. The preheating module (10) according to claim 4, wherein, The third series of inner walls (22c) extends from the first outer peripheral wall (23), and the fourth series of inner walls (22d) extends from the second outer peripheral wall (24). The third series of inner walls (22c) and the fourth series of inner walls (22d) are arranged parallel to each other and alternate one after another.

9. The preheating module (10) according to any one of the preceding claims, wherein, The heat transfer wall (30) includes a plurality of first openings (31) that occupy 20% to 35% of the total area of ​​the heat transfer wall (30), excluding end values.

10. The preheating module (10) according to any one of the preceding claims, wherein, The diffusion chamber (12) includes a plurality of diffusion walls (35), each diffusion wall (35) including a second opening (36), the second opening occupying 35% to 50% of the total area of ​​the diffusion wall (35), preferably occupying 40% to 60% of the total area of ​​the diffusion wall (35).

11. A furnace (1) for consolidating and densifying a component (P) made of a ceramic matrix composite material, the furnace (1) comprising a processing module (2) and a preheating module (10) according to any one of the preceding claims, the processing module comprising a cavity (3) for receiving the component (P), the preheating module being located below the processing module (2) and forming a second stack with the processing module (2) along the stacking axis (X).

12. A method (100) for consolidating and densifying a ceramic matrix composite component (P), said method being carried out in a furnace according to claim 11, said method comprising the following steps in sequence: Step 110) Provide the furnace according to claim 11, Step 120) Wait for the temperature (T) in the inrush unit (20) to reach the desired level. UE ) to reach the desired temperature (T) relative to the processing module (2). MC The temperature (T) in the diffusion chamber (12) is between 100°C and 200°C. CD ) to reach the desired temperature (T) relative to the processing module (2). MC Values ​​between 30°C and 5°C below 30°C. Steps 130) and 120) are performed simultaneously or after step 120), the gas mixture is injected into the furnace and the process is continued until the gas mixture reaches the desired temperature (T). MC ).

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