Production of complex components by additive manufacturing

Abstract

The present invention proposes that a bridging portion (9) extending side by side connects the radial inner wall (5) and the radial outer wall (3) of the combustion chamber of a gas turbine to the free end (5a) of the radial inner wall (5) to form an integral part, which has an additive layer structure as a whole.

Description

Field of the Invention

[0001] The present invention relates to the production of quite complex parts by additive manufacturing in the field of aeronautic turbomachines.

[0002] Thus, it relates to the production of at least a part of a combustion chamber of a gas turbine by additive manufacturing.

[0003] This production can be carried out in particular by additive manufacturing on a powder bed. Background Art

[0004] Additive manufacturing makes it possible to manufacture parts with relatively complex geometries without the limitations associated, for example, with the use of molds. However, this manufacturing method is still limited by the amount of time required for manufacturing, the high manufacturing costs, and some difficulties involved in its implementation.

[0005] FR3041889 and EP3002212 propose technical solutions for the production of parts by additive manufacturing, in particular on a powder bed. The details of these production techniques can be applied here.

[0006] In this general context, the subject of the present invention specifically relates to the production of at least a part of a combustion chamber of a gas turbine by this method.

[0007] To protect the walls from the heat, it is known that it is effective to establish an air film in this combustion chamber. This film can be obtained by a double wall of short length supplied with air channels (commonly called holes) crossing a wall. The double wall guides the air along the surface to be protected in a more uniform manner.

[0008] The prior art solutions for forming such zones of the combustion chamber consist of manufacturing independently a piece of sheet metal that will delimit an internal lining wall from the outer wall of the actual body of the combustion chamber, and then assembling it by welding or soldering this piece of sheet metal to the said body while maintaining a gap to ensure the air film.

[0009] This forces the boiler to act on the parts to be assembled to position the said parts correctly.

[0010] After assembly, a calibration operation is required so that the spacing between the walls is suitable to ensure a uniform flow of the air film.

[0011] These operations directly affect the cost and the production cycle.

[0012] The aim of the present invention is to solve at least some of the aforementioned problems. Summary of the Invention

[0013] To improve the situation, the present document proposes a method for producing at least a part of a combustion chamber of an aero-turbine by additive manufacturing, the aero-turbine extending around an axis (hereinafter referred to as X1) and including a radially outer wall, the radially outer wall being locally lined with a radially inner wall to form an intermediate space therebetween for generating an air film. In particular, this method is characterized in that it is carried out from bottom to top and by additive manufacturing:

[0014] - simultaneously, producing a lower part of the radially outer wall by depositing a succession of material layers, continuing the deposition of the material layers to build bridges on the lower part, the bridges being established adjacent to each other until the top of the bridges, where

[0015] - continuing the deposition of the material layers to produce the radially inner wall while continuing to build the radially outer wall, and

[0016] - continuing the deposition of the material layers at least until the lower part of the radially outer wall engages with the radially inner wall end located opposite the bridge.

[0017] Thus, at the upstream end, the radially inner wall will engage the radially outer wall.

[0018] This upstream connection end of the base of the combustion chamber can be important.

[0019] In fact, in this way it will be possible to produce the radially inner wall in the same part as the radially outer wall, while the manufacturing direction does not allow the production of a hanging wall.

[0020] It will be easy to manufacture these supports or struts forming a succession of bridges.

[0021] "Radial" means radial with respect to the axis X1. The radially outer wall is further away from the axis X1 in this direction compared to the radially inner wall.

[0022] If it is further proposed to carry out additive manufacturing on a metal powder bed by means of a laser, then the bridges arranged in this way make it possible to dissipate the energy of the laser and obtain the solidification of the metal necessary for building the radially inner wall.

[0023] If it is also proposed that the radially outer wall and the radially inner wall extend parallel to each other above a part of the lengths of the radially outer wall and the radially inner wall of the bridge respectively between their connection ends, then this effect of energy dissipation, and then a good air flow in the space between the radially outer wall and the radially inner wall respectively, may be even better.

[0024] This does not prevent them from being connected (engaged) with each other on the upstream side of the combustion chamber, the two walls being inclined with respect to the axis X1 and thus moving closer to this axis X1 towards the upstream, where the radially outer wall has a steeper slope towards the upstream end (in the followingFigure 2 In this case, the face 30b may be substantially perpendicular to the axis X1).

[0025] This steeper slope of the radially outer wall (hereinafter, it may thus be at the position of the face 30b) may belong to the base of the combustion chamber, which is positioned along the axis X1 at the upstream end of the combustion chamber and is axially opposite to an opening centered on the axis X1. The combustion chamber has such an opening at the downstream end for discharging hot gases from the combustion in the combustion chamber.

[0026] In order to allow combustion air and / or fuel (predominantly fuel oil) to enter the combustion chamber, the aforementioned base may be annular and have a central passage centered on the axis X1.

[0027] Perpendicular to the axis X1, the cross-section of this central passage is smaller than the cross-section of the opening for discharging hot gases.

[0028] Additive manufacturing also makes it possible to continuously produce, annularly around the axis (X1), by continuing to deposit the material layer after manufacturing the lower combustion chamber region, as explained above:

[0029] - the radially outer wall,

[0030] - the radially inner wall, and

[0031] - the bridging portions, which are arranged adjacent to each other towards the end of the radially inner wall opposite to the place where the radially inner wall joins the radially outer wall:

[0032] -- by respectively manufacturing the radially outer and radially inner polygonal walls (of the other parts of these walls) around the axis (X1), and

[0033] -- by tilting the bridging portions such that the bridging portions extend transversely to the sides of the polygon in which they are located and respectively between the radially outer wall and the radially inner wall.

[0034] Thus, by tilting the considered bridging portions, they will be able to extend respectively between the radially outer walls, at least for some, not necessarily in a perpendicular manner, but in a tilted manner (tilted) with respect to the relevant sides. Angles other than 90° may exist, for example, angles between 10° and 80°.

[0035] In order to supply air to the space generated between the radially outer wall and the radially inner wall, it is useful to have openings in the radially outer wall that can lead to this space.

[0036] The orientation of at least some of these openings will be completely parallel to the axis (X1) for efficient air purge.

[0037] Furthermore, the method of the present invention also relates to a combustion chamber of a gas turbine, which respectively includes a radial outer wall and a radial inner wall surrounding the axis (X1), and the walls have a local lining to form an intermediate space therebetween capable of generating an air film.

[0038] More precisely, the present invention relates to a combustion chamber of a gas turbine having an axis (X1), the combustion chamber having an upstream side and a downstream side along the axis, the combustion chamber including a radial outer wall surrounding the axis (X1), the radial outer wall being locally lined with a radial inner wall, the two walls being spaced apart from each other to form an intermediate space therebetween capable of generating an air film, and further having the following characteristics:

[0039] - A single bridging portion extending adjacent to each other connects (joins) the radial inner wall and the radial outer wall towards the free end of the radial inner wall into an integral piece, and

[0040] - The two walls, namely the radial outer wall and the radial inner wall respectively:

[0041] -- Are connected (joined) to each other on the upstream side (thus towards the end opposite to the free end),

[0042] -- And thus are inclined with respect to the axis (X1) in a direction considered to be upstream-directed, towards the axis (X1), and the radial outer wall has a steeper slope towards the upstream joining side end than downstream.

[0043] Therefore, with respect to the axis (X1), the radial outer wall advantageously has a steeper slope towards its upstream connection end than downstream towards the free end.

[0044] Of course, it should be understood that the above-mentioned "upstream connection end" is the (upstream) end of the radial outer wall, where the latter connects / joins the upstream connection end to the upstream connection end of the radial inner wall.

[0045] Further downstream of their respective "upstream connection ends", the radial inner wall and the radial outer wall can effectively become substantially parallel, thus avoiding the so-called intermediate space at the free end of the radial inner wall and thus avoiding an inappropriate air film because the space it occupies is too small.

[0046] Among the characteristics of this combustion chamber, it should be noted that a single bridging portion extending side by side connects the radial inner wall and the radial outer wall to the free end of the radial inner wall:

[0047] - Connected into an integral piece, and / or

[0048] - Such that the bridging portion and at least locally the radial inner wall and the radial outer wall are obtained by stacking successive layers;

[0049] This technique is generally referred to as "additive layer structure".

[0050] As mentioned above, this should improve the situation regarding at least some of the aforementioned drawbacks.

[0051] The expression "having an additive layer structure" has the meaning of being an integral part, and also the meaning of "being produced by additive manufacturing", having the physico-chemical structure characteristic of this manufacturing and being identifiable and thus distinguishable from the manufacturing processes of casting or injection by the physico-chemical analysis of this structure.

[0052] In order to facilitate a continuous periphery (around axis X1) for the uniform passage of the support film wall and air, it is further proposed that on this combustion chamber, at one end where it is connected to the radial inner wall, the bridging part unfolds outwards:

[0053] - until they come into contact in pairs, and / or

[0054] - at an angle of less than 150° or between 120° and 160°.

[0055] Again, in order to facilitate the uniform passage of air, it is also proposed that:

[0056] - around the said axis (X1), the radial outer wall and the radial inner wall respectively have polygonal faces, and

[0057] - perpendicular to the direction in which the bridging part connects the radial inner wall and the radial outer wall, and perpendicular to the direction in which the radial inner wall and the radial outer wall extend around the axis (X1), the bridging part is elongated and each has a double bevel end.

[0058] Regarding the openings for the air in the radial outer wall, the openings being open between the radial outer wall and the radial inner wall, it is even proposed that:

[0059] - the openings are formed on several faces of the radial outer wall along several parallel lines, and / or

[0060] - the openings respectively have a convex pentagonal shape.

[0061] Finally, the present invention also relates to an aero-turbine including a combustion chamber having all or part of the above features.

[0062] Regarding additive manufacturing, this technique involves a method of manufacturing components volumetrically by adding or coalescing materials and by stacking successive layers. Using computer-aided design, specific software organizes the various sliced layers required to manufacture the component. The use of several materials makes it possible to obtain components with zero and / or controlled thermal expansion or other physical properties. Steps such as hot isostatic pressing, cold isostatic pressing, or vacuum densification isostatic pressing can be provided to obtain components that are particularly free of unwanted anisotropy or porosity. The components can include metallic alloys and / or ceramic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 Figure 1 Describes a possible embodiment of the technical solution according to the present invention, which shows the upstream lower part of the combustion chamber of an aero turbine in perspective and axial section (axis X1).

[0064] Figure 2 Figure 2 Describes the section according to what is seen along arrow IIe Figure 1 .

[0065] Figure 3 Figure 3 Describes the section according to what is seen along arrow III Figure 1 .

[0066] Figure 4 Figure 4 Represents the view according to what is seen along arrow IV Figure 1 .

[0067] Figure 5 Figure 5 Is a rough axial cross-section of the above combustion chamber. DETAILED DESCRIPTION

[0068] In the following description, the same reference numerals denote the same parts or parts having similar functions.

[0069] Thus, the subject matter of the present invention is the combustion chamber of an aero (gas) turbine, which is labeled 1 in the drawings (especially Figure 5 ).

[0070] As is well known, this combustion chamber 1 is inserted between the compressor and the turbine, the compressor being upstream with respect to the overall direction of the gas flow in the turbine, and the turbine being downstream.

[0071] ​​​​​​​​​​Upstream, an air and fuel injection system supplies air and fuel to the combustion chamber. A portion of the upstream air from the compressor is directed through the injection system for forming a fuel mixture injected along axis X1. The mixture passes through the main zone where the combustion reaction occurs inside the combustion chamber, and then the resulting gases are further diluted and cooled in the secondary zone and distributed to the turbine it drives.

[0072] X1 is also the axis around which the combustion chamber 1 extends from upstream to downstream.

[0073] Thus, the combustion chamber 1 has a base at its upstream end along axis X1 that is traversed by a central channel in the center, and a hot gas discharge opening at its downstream end, see Figure 5 .

[0074] As can also be seen in Figure 5 , perpendicular to axis X1, the cross-section of the central channel is preferably smaller than the cross-section of the hot gas discharge opening.

[0075] The gas turbine equipped with the combustion chamber 1 can be a dual-flow and dual-body turbofan engine that has a fan, a low-pressure compressor, a high-pressure compressor, and an annular combustion chamber, a high-pressure turbine, and a low-pressure turbine from upstream (AM) to downstream (AV).

[0076] As particularly shown in Figure 1 , the combustion chamber 1 includes a radially outer wall 3 that is locally lined with a radially inner wall 5 around axis X1.

[0077] Thus, there is an intermediate space 7 between the radially outer wall 3 and the radially inner wall 5. An air film can be generated between the walls.

[0078] To fabricate the radially inner wall 5 in the same part as the radially outer wall 3, bypassing the problem of forming a hanging wall, a single bridging portion 9 that extends adjacent to each other connects the radially inner wall 5 and the radially outer wall 3 into a single piece towards the free end 5a of the radially inner wall 5.

[0079] In other words, at least locally, as in the lower zone 10 of the combustion chamber 1 ( Figure 5 ), the bridging portion 9, as well as the radially inner wall 5 and the radially outer wall 3, are made into a single piece and have a common additive layer structure.

[0080] To contribute to the peripheral (around axis X1) continuity for supporting (the support for the lower zone 10) the radially inner wall 5 and the uniform passage of air in the intermediate space 7, it may be useful to have a bridging portion 9 that flares out at one end (or top) 9a where it is connected to the radially inner wall 5.

[0081] In particular, the bridging portion 9 can flare out:

[0082] - until they come into contact in pairs (zone 11, Figure 3 ), and / or

[0083] - at an angle A of less than 150° or between 120° and 160°.

[0084] This is a compromise between the additive manufacturing capacity and the mechanical effect to be achieved.

[0085] To further promote a uniform air flow (reasonably stable), it is advisable that:

[0086] - around the axis X1, the radial outer wall 3 and the radial inner wall 5 have polygonal faces (see Figure 4 ), and

[0087] - that is to say, perpendicular to the direction in which the inner wall 5 and the outer wall 3 are connected by the bridging portion 9, and perpendicular to the direction (Y1) in which these walls 3 and 5 extend around the axis X1, the bridging portion 9 is elongated (direction Xp, Figure 1 ) and has double bevel ends 9b1, 9b2.

[0088] The conical ends 9b1, 9b2 are aerodynamic, and the bridging portion 9 stabilizes the air flow from upstream to downstream, and the length (direction Xp) of the bridging portion is longer than its width.

[0089] Providing the openings 13 in the radial outer wall 3 into the intermediate space 7 will ensure circulation, which helps to generate the required air film along the inner side of the radial outer wall 3.

[0090] Regarding these openings 13, it has even been proposed that:

[0091] - they are preferably formed on a plurality of faces of the radial outer wall 3, such as 30a, 30b, etc., along several lines parallel to each other, and / or

[0092] - they each have the form of a convex pentagon (see Figure 1 ).

[0093] The convex pentagon's convex face portion 13a with double bevels is preferably positioned closer to the axis X1 than the other sides of the pentagon.

[0094] Therefore, it is useful to associate the polygonal face design of the walls 3, 5 suitable for additive manufacturing and the distribution of the openings 13 distributed around the axis X1 with optimized mechanical strength (convex pentagon shape).

[0095] Regarding the production of at least one part of the combustion chamber, such as part 1, it should be noted that, with particular attention, due to additive manufacturing, the production is carried out from bottom to top (respectively L and H and the arrow, Figure 2 ).

[0096] Thus, while generating the lower part 30 (lower zone 10) of the radial outer wall 3 by depositing a succession of material layers, the deposition of such material layers is continued to build up on the lower part bridging portions 9, which are then arranged adjacent to one another up to the tops 9a of these bridging portions.

[0097] At this time, the deposition of the material layers can be continued to generate (start to generate) the radial inner wall 5 while continuing to generate the radial outer wall 3.

[0098] Over time, the material layers are continuously deposited at least until the lower part 30 of the radial outer wall 3 meets (is parallel to the axis X1) the end 5b of the radial inner wall 5 opposite 5a at the location where the bridging portions 9 are located.

[0099] Thus, in the lower zone 10, the radial inner wall 5 is inclined with respect to the axis X1 and rises towards its end 5b where it is connected to the radial outer wall 3.

[0100] The radial outer wall 3 is also inclined with respect to the axis X1.

[0101] Preferably, for a compromise between manufacturing, mechanical strength and aerodynamic operation, it is desirable in this regard for the radial outer wall 3 and the radial inner wall 5 to be parallel to one another over most of the length L of the radial inner wall 5 extending between the ends 5a and 5b.

[0102] Over the remainder of the profiles (closed and thus peripheral) of the radial outer wall 3 and the radial inner wall 5, if the aforementioned manufacturing techniques are also used, it is desirable to proceed in the same way: to incline the two walls 3 and 5 with respect to the axis X1 but with opposite advance directions in the upper part of the walls 3, 5 and thus of the combustion chamber 1, i.e. by raising the radial inner wall 5 from its end 5b connected to the radial outer wall 3 towards its free end 5a, where the bridging portions 9 will rise until they are connected to the radial outer wall 3 which the ongoing layer deposition will continue to generate simultaneously.

[0103] In this regard, it should be noted that, taking into account the compromise (between manufacturing, mechanical strength and aerodynamic impact), while continuing to deposit the material layers, the radial outer wall 3, the radial inner wall 5 and the bridging portions 9 are continuously generated around the axis X1, and the bridging portions are then arranged adjacent to one another towards the free end 5a of the radial inner wall 5:

[0104] - by forming the polygonal radial outer wall 3 and the radial inner wall 5 around the axis X1, and

[0105] - by inclining the bridging portions 9 such that the bridging portions extend transversely between the radial outer wall 3 and the radial inner wall 5 with respect to the sides (faces) of the polygon on which they are arranged: see for exampleFigure 2 : The bridging portion 9 can be vertically arranged between the face 30a of the radially outer wall 3 and the substantially parallel face 50a of the radially inner wall 5, these two faces being inclined with respect to the axis X1 and approaching this axis X1 in the upstream direction.

[0106] Here, the term "transverse" does not necessarily mean perpendicular to the relevant side, and can also be inclined with respect to the relevant side.

Claims

1. A method for producing at least one part of a combustion chamber of an aero turbine by additive manufacturing, the combustion chamber of the aero turbine extending around an axis (X1) and including a radially outer wall (3), the radially outer wall being locally lined with a radially inner wall (5) to form an intermediate space (7) therebetween capable of generating an air film, the method being characterized in that it is carried out from bottom to top and by additive manufacturing: - simultaneously, producing a lower part (30) of the radially outer wall (3) by depositing a succession of material layers, continuing the deposition of the material layers to build bridges (9) on the lower part, the bridges being established adjacent to each other until the top (9a) of the bridges, wherein - continuing the deposition of the material layers to produce the radially inner wall (5), while continuing to build the radially outer wall (3), and - continuing the deposition of the material layers at least until the lower part (30) of the radially outer wall (3) is joined to the end (5b) of the radially inner wall opposite the position of the bridges (9), and: - by manufacturing the radially outer wall (3) and the radially inner wall (5) around the axis (X1) according to a polygonal design, and - by manufacturing the bridges (9) such that the bridges (9) extend in an inclined manner between the radially outer wall (3) and the radially inner wall (5), rather than perpendicular to the sides of the polygon on which they are arranged, such that the bridges (9) are arranged adjacent to each other towards the end of the radially inner wall (5) opposite the place where the radially outer wall (3) is joined to the radially inner wall (5).

2. The method according to claim 1, characterized in that, Additive manufacturing is performed on a metal powder bed.

3. The method according to claim 1, characterized in that, The outer radial wall (3) and the inner radial wall (5) are parallel to each other above a part of the length of the inner radial wall extending between the ends.

4. The method according to claim 1, characterized in that, In the outer radial wall (3), an opening (13) is made that is open between the outer radial wall (3) and the inner radial wall (5).

5. A combustion chamber of a gas turbine having an axis (X1), the combustion chamber having an upstream side and a downstream side along the axis, the combustion chamber comprising: - An outer radial wall (3) around the axis (X1), the outer radial wall being locally lined with an inner radial wall (5) to form an intermediate space (7) therebetween capable of generating an air film, - A single bridging portion (9) extending closely adjacent to each other, which joins the inner radial wall and the outer radial wall into a single piece towards the free end (5a) of the inner radial wall (5), the outer radial wall (3) and the inner radial wall (5) being joined to each other respectively at the upstream side towards the end opposite the free end (5a), and thus being inclined with respect to the axis (X1) in a direction considered to be upstream-directed, towards the axis (X1), the outer radial wall having a steeper inclined surface at the upstream of the side towards the joining end. Wherein: - Around the axis (X1), the outer radial wall (3) and the inner radial wall (5) have polygonal faces, and - Perpendicular to the direction in which the bridging portion (9) joins the inner radial wall and the outer radial wall, and perpendicular to the direction in which the inner radial wall (5) and the outer radial wall (3) extend around the axis (X1), the bridging portions are elongated and each has a double beveled end.

6. The combustion chamber according to claim 5, characterized in that, At the end where the bridging portion (9) joins the inner radial wall (5), the bridging portion flares out until they come into contact in pairs and / or form an angle of less than 150° or between 120° and 160°.

7. The combustion chamber (1) according to claim 5, which has an opening (13) in the radial outer wall (3) that is open between the radial outer wall and the radial inner wall.

8. The combustion chamber according to claim 7, characterized in that The opening (13) is formed on a plurality of faces of the outer radial wall (3) according to a plurality of parallel lines and / or has the form of a convex pentagon respectively.

9. An aero-turbine machine, which comprises a combustion chamber (1) according to any one of claims 5 to 8.

Images