METHOD FOR MANUFACTURING A TURBINE ENGINE CASING WITH ABRADABLE COATING

Abstract

The invention relates to a method for manufacturing a panel for supporting at least one cartridge of abradable material for a turbine engine casing, said panel including at least one block of honeycomb material covered with a rigid skin, characterised in that it includes: a step of machining (ET5) an outer surface of a block of material, in particular a honeycomb material, according to a three-dimensional profile configured to match that of an inner surface of the casing; and then, a step (ET6) of adhering the block of machined material to the rigid skin.

Claims

1. Method for manufacturing a panel for supporting at least one cartridge of abradable material for a turbine engine casing, said panel including at least one block of material and a rigid panel covering said block, except for a free outer surface configured to be fixed to an inner surface of the casing, wherein said method includes: a step of machining (ET5) the outer surface of the block of material according to a three-dimensional profile configured to match that of the inner surface of the casing, then a step of fixing (ET6) the machined block to the rigid panel.

2. The method according to claim 1, wherein during the machining step (ET5), the outer surface of the block is machined up to a determined thickness (E2), and in that, prior to the fixing step (ET6), a rigid panel including a wall and edges defining rims of determined height (H) less than said determined thickness (E2) of the block are selected.

3. The method according to claim 2, wherein during the fixing step (ET6), the wall of the panel is adhered onto an inner surface of the block and the rims onto the edges of said block.

4. The method according to claim 1, wherein it includes a prior step (ET1) of manufacturing the panel by cooking an impregnated composite material.

5. The method according to claim 1, wherein it includes a prior step (ET3) of measuring dimensions of an inner surface of the casing to determine the three-dimensional profile of said inner surface.

6. Panel for supporting at least one cartridge of abradable material for a turbine engine, said panel including at least one block of material which includes an outer surface configured to be adhered to an inner surface of a turbine engine casing and which is covered with a rigid panel, said rigid panel including a wall covering an inner surface of the block and edges defining rims in regard to edges of said block, wherein the outer surface of the block is machined and in that the rigid panel is fixed to the block by way of an adhesive film, said adhesive film being interleaved between the wall of the panel and the inner surface of the block and between the rims of the panel and the side edges of said block.

7. The panel according to claim 6, wherein a free end of the rims is arranged set back from the outer surface of the block.

8. The panel according to claim 6, wherein the panel is made of a cooked, impregnated composite material.

9. The method for manufacturing a turbine engine casing with abradable coating, including a turbine engine casing covered with a panel for supporting at least one cartridge of abradable material for a turbine engine, said panel including at least one block of material which includes an outer surface configured to be adhered to an inner surface of a turbine engine casing and which is covered with a rigid panel, said rigid panel including a wall covering an inner surface of the block and edges defining rims in regard to edges of said block, wherein the outer surface of the block is machined and in that the rigid panel is fixed to the block by way of an adhesive film, said adhesive film being interleaved between the wall of the panel and the inner surface of the block and between the rims of the panel and the side edges of said block, said panel receiving a cartridge of abradable material, wherein said method successively includes a first phase (P1) during which the steps (ET5, ET6) of the method for manufacturing a panel according to claim 1 are implemented, to obtain at least one panel, a second phase (P2) during which said panel is adhered on the inner surface of the casing, and a third phase (P3) during which a cartridge made of abradable material is adhered on said panel.

10. The method for manufacturing a casing with abradable coating according to claim 9, wherein the second phase (P2) of said method occurs simultaneously with the adhering step (ET6) of the method for manufacturing the panel.

11. The turbine engine including at least one panel for supporting at least one cartridge of abradable material for a turbine engine, said panel including at least one block of material which includes an outer surface configured to be adhered to an inner surface of a turbine engine casing and which is covered with a rigid panel, said rigid panel including a wall covering an inner surface of the block and edges defining rims in regard to edges of said block, wherein the outer surface of the block is machined and in that the rigid panel is fixed to the block by way of an adhesive film, said adhesive film being interleaved between the wall of the panel and the inner surface of the block and between the rims of the panel and the side edges of said block, said panel obtained by the method according to claim 1.

Description

[0038] The invention will be best understood and other details, characteristics and advantages of the present invention will appear more clearly upon reading the following description made as a non-limiting example, and in reference to the appended drawings, wherein:

[0039] FIG. 1 is a schematic, cross-sectional view of a turbine engine casing with abradable coating according to a prior art;

[0040] FIGS. 2A and 2B are schematic views representing a part of the steps of a method for manufacturing a support panel according to a prior art;

[0041] FIG. 3 is a schematic view representing a final phase of a method for manufacturing a casing with abradable coating of FIG. 1;

[0042] FIG. 4 is a flowchart representing the phases of a method for manufacturing the casing with abradable coating of FIG. 1;

[0043] FIG. 5 is a schematic, cross-sectional view of a casing with abradable coating according to the invention;

[0044] FIGS. 6A and 6B are schematic views representing a part of the steps of a method for manufacturing a support panel according to the invention;

[0045] FIG. 7 is a schematic view representing a final phase of a method for manufacturing the casing with abradable coating of FIG. 5;

[0046] FIG. 8 is a flowchart representing the phases of a method for manufacturing the casing with abradable coating of FIG. 5.

[0047] In the following description, identical reference numbers mean identical parts, or parts with similar functions.

[0048] Through the present description, the orientations inner and outer are defined by reference to an axis of rotation of the rotors of a turbine engine, the orientations outer being rotated opposite said axis, and the orientations inner being rotated towards said axis.

[0049] In FIGS. 1 and 5, a casing with abradable coating 10 for a turbine engine has been represented.

[0050] In a known manner, such a casing with abradable coating 10 includes a bare casing 12 which is coated with a support panel 14 which is itself coated with a cartridge 16 made of abradable material.

[0051] The support panel 14 includes at least one block 18 of honeycomb material, known generally under the name of Nida, and a rigid panel 20 which covers the block 18 and which is intended to receive the cartridge 16 made of abradable material.

[0052] Thus, the support panel 14 is shaped in the form of a half-sandwich which is fixed to an inner surface 13 of the casing 12 by way of an adhesive film 22.

[0053] The cartridge of abradable material 16 is fixed to the support element 14 by adhering, and especially, by cooking the abradable material. The cooking of the abradable material ensures the cohesion therefore with the support panel 14.

[0054] FIG. 1 illustrates more specifically a casing with abradable coating 10 produced conforming with a prior art. This casing with abradable coating 10 includes especially a support panel 14 which is produced according to a method which has been represented in FIGS. 2A and 2B corresponding to the steps of FIG. 4.

[0055] According to this method, during a first step ET1 which has been represented in FIG. 2A, a block 18 of honeycomb material is inserted into a panel perform 26 made of impregnated composite material, for example a perform 26 made of woven carbon fibres and impregnated with an epoxy resin. The preform 26 includes a wall 28 and the edges defining rims 30. During the insertion of the block 18 of honeycomb material in the preform, an intumescent material 32 is interleaved between the edges 34 of the block 18 of honeycomb material and the rims 30 of the preform 26.

[0056] The assembly shaped substantially in the form of a half-sandwich, is subjected to a simple cooking during a second step ET2 and so as to form a raw support panel.

[0057] From this step ET2, the panel preform 26 made of composite material has become a rigid panel 20 such as represented in FIG. 2B. The block 18 of honeycomb material, the intumescent material 32, and the panel 20 are adhered to each other following the cooking of the composite material.

[0058] Moreover, the inner surface 13 of the casing 12 represented above in FIG. 1 does not necessarily correspond to the theoretical profile thereof. Especially, in the case of a rotating casing 12 made of composite material, it has been observed that the inner surface 13 of the casing 12 after manufacture could not present a perfectly circular section, but rather an ovalised section, unsuitable for receiving a compressor or turbine wheel of the turbine engine (not represented). Furthermore, the inner surface 13 of the casing 12 can present possible surface defects.

[0059] Insofar as the panel 20 is rigid and where the general shape thereof must no longer be modified, as it must have a minimum thickness, itself making it possible to support the cartridge of abradable material 16, it is therefore necessary to proceed with a machining of an outer surface 36 of the support panel 14 so that it matches the inner surface 13 of the casing 12 in order to minimise the deformations that the support panel 14 could be subjected to with respect to the theoretical profile thereof. Indeed, such deformations would consequently have to modify the position required for the support panel 14, and consequently for the cartridge of abradable material 16 that the support panel 14 must receive.

[0060] To do this, as FIG. 4 illustrates it, during a third step ET3 (not represented), the inner surface 13 of the casing 12 is measured so as to deduce from it a three-dimensional profile that the outer surface 36 of the support panel 14 must match. Then, during a fourth step ET4, the support panel 14 is placed in a suitable tooling (not visible) which allows to stress the panel 14 according to a position, analogue to that that it must occupy once mounted in the casing 12.

[0061] For example, this stress can consist, when the panel 14 has an annular shape, of a radial stress being exerted along the whole of the periphery of the outer surface 36 of the panel 14 or, when the panel 14 presents a shape of angular sector as represented in FIGS. 2A and 2B, in a stress exerted radially over the periphery of the outer surface 36 and tangentially over the rims 30 of the panel 14, as the panel 14 is intended to be arranged between two panels 14 of the same type which consequently exert on it, tangential forces at the level of these two rims 30.

[0062] It will be understood that other stresses can be exerted to stress the panel 14 to the mounted position thereof in the casing 12, without limiting the invention.

[0063] Then, during a fifth step ET5 which has been represented in FIG. 2B, the outer surface 36 of the support panel 14 is then machined according to a three-dimensional profile, corresponding to that of the inner surface 13 of the casing 12, for example using an end mill 37.

[0064] The first and fifth steps ET1 to ET5 of the method for manufacturing the support panel 14, comprising especially steps ET1 and ET5 which have been represented in FIGS. 2A and 2B, constitute a first phase P1 of the method for manufacturing the casing with abradable cover. Then, during a second phase P2 represented in FIG. 4 and illustrated in FIG. 3, the support panel 14 is adhered onto the inner surface 13 of the casing and finally, during a phase P3, the cartridge 16 of abradable material is adhered onto the support panel 14.

[0065] These methods present several disadvantages.

[0066] Firstly, they impose, during step ET3, an operation of measuring the inner surface 13 of the casing 12 with highly increased tolerances, as, like the support panel 14 is made rigid at the end of step ET2 of cooking the panel 20, the slightest shape defect of the inner surface 13 of the casing panel 12 leads to a defect in positioning the support panel 14 after the fixing thereof onto the casing 12.

[0067] Especially, as FIG. 1 illustrates it, with the outer ends 38 of the rims 30 being directly in contact with the inner surface 13 of the casing 12, any defect of this inner surface 13 leads to a defect in positioning the wall 28 of the support panel 14, and consequently the cartridge 16 of abradable material.

[0068] Secondly, the machining operation of step ET5 is moreover very constricting to implement, this by the nature of the tooling that it involves. As has been seen, once cooked, the support panel 14 is found considerably stiffened by the panel 20 made of composite material. The stressing of the support panel 14 in the tooling in order to stress in the position that it must occupy once mounted in the casing, involves a tooling capable of conferring the suitable deformations of the panel 14, while ensuring a holding such that it does not break free from said raised tooling of the support panel.

[0069] Thirdly, the second cooking step is itself problematic. Indeed, as the connection of the block 18 to the panel 20 is achieved by cooking the support panel 14 in the entirety thereof, it is necessary to cook this assembly as a half-sandwich in an autoclave enclosure. Consequently, the manufacturing in series of such supports 14 of cartridges of abradable material involves a thorough management of usage and occupation time of the autoclave enclosures which complicates the management of production flows.

[0070] Lastly, the insertion of the intumescent material 32 between the edges of the block of honeycomb material and the rims of the panel made of composite material increases the risks of deforming the support panel 14. Indeed, the expansion of the intumescent can produce craters, porosities, delamination at the level of the rims 30, which requires, almost systematically, an adjustment of the rims 30 to obtain the final support panel 14.

[0071] This disadvantage is overcome by proposing a method for manufacturing the support panel 14 and a method for manufacturing the casing with abradable coating 10 which advantageously allow the manufacturing of the support panel 14 by using conventional cooking means and allow the machining of the block 18 of honeycomb material with a reduced tooling and according to lower tolerances.

[0072] Conforming with the invention, as illustrated by FIGS. 6A, 6B and 7, the method successively includes at least one step ET5 of machining the outer surface 36 of the block 18 of honeycomb material according to a three-dimensional profile configured to match that of an inner surface of the casing, then a step ET6 of adhering the machined block 18 to the rigid panel 20.

[0073] The implementation of this method can assume the provision of a rigid panel 20 which can already be formed, and for example, form part of a panel 20 stock, available to the operator responsible for the manufacturing, or in a variant, of a panel which is formed at the time of the implementation of the method. Now, a preferred embodiment of the method will be described, being understood that this embodiment is not, in the organisation thereof, limiting of the invention, provided that the method includes at least one step of machining the outer surface 36 of the block 18 and the step of adhering the machined block 18 to the rigid panel 20.

[0074] As FIG. 8 illustrates, the method for manufacturing the support panel 14 according to the invention preferably includes a first step ET1, during which the panel 20 made of composite material is manufactured by cooking an impregnated composite material, for example a carbon fibre material impregnated with epoxy resin. A panel 20 is thus obtained, preferably rigid, including a wall 28 and rims 30, as represented in FIG. 6A. The panel 20 is configured to leave free, on the block 18, an outer surface 36 configured to be fixed to an inner surface 13 of the casing 12 such as represented in FIG. 5.

[0075] Then, or at the same time, as these operations can be led simultaneously, the method includes a step ET2 of cutting the block 18 of honeycomb material according to dimensions specific to being suitable to those of the wall 28 of the panel 20, the aim of this operation being, of course, to guarantee that the block 18 can be covered with the panel 20.

[0076] Then, or at the same time, as these operations can be led simultaneously, the method includes a third step ET3 of measuring the inner surface 13 of the casing 12 to determine the three-dimensional profile of said inner surface 13. This third step ET3 of the method is not limiting of the invention, but it allows, however, to characterise very precisely the profile of the inner surface 13 in order to specifically measure all the defects of it.

[0077] Then, during a fourth step ET4, the block 18 is positioned on a tooling (not visible), able to confer to it a position corresponding to the final position that it is intended to occupy in the panel 14 mounted in the casing 12.

[0078] Advantageously, as the block 18 is not rigidified by the rigid panel 20, the tooling used does not require to prestress the block 18 to obtain the final position that it is intended to occupy in the panel 14 mounted in the casing 12. This configuration allows to use a simpler tooling.

[0079] Then, at least one step ET5 of machining the outer surface 36 of the block 18 of honeycomb material is carried out according to a three-dimensional profile, configured to match that of the inner surface 13 of the casing 12, as represented in FIG. 6B.

[0080] With respect to the method such as described above in reference to the state of the art, this method advantageously allows to machine a block 18 of honeycomb material which is more flexible that above, as it is not rigidified by the rigid panel 20. Because of this, the machining can be advantageously done as above, with an end mill 37, but it is not necessary to have a tooling making it possible to stress and to precisely hold the block 18 of honeycomb material, as it is not rigidified by the panel 20 and is therefore more flexible.

[0081] Then, as FIG. 7 illustrates it, during a step ET6 of adhesion, the previously machined block 18 of honeycomb material is fixed to the panel 20 by way of an adhesive film 40.

[0082] Preferably, by way of the adhesive film 40, an outer surface 27 of the wall 28 of the panel made of composite material 20 is adhered onto an inner surface 42 of the block 18 of honeycomb material, and the rims 30 onto the edges 34 of said block 18 of honeycomb material.

[0083] Advantageously, in the preferred embodiment of the method for manufacturing the support element 14, the block 18 of honeycomb material is machined during the step ET5 according to a thickness E1, represented in FIG. 6B.

[0084] During the first step ET1, a rigid panel 20 including edges defining rims 30 of determined height H, as represented in FIG. 6A, is manufactured or selected. The height H of the rims 30 is provided to be less than the height E1 of the block 18.

[0085] This configuration is particularly advantageous. Indeed, the support panel 14 obtained presents rims 30 of which the free end is therefore likely to be arranged set back from the plane of the outer surface 36 of the block 18.

[0086] This configuration allows to guarantee that, when the block 18 of honeycomb material is assembled with the rigid panel 20, the outer ends 38 of the rims 30 do not come and touch the inner surface 13 of the casing 12, as represented by the detail marker and the associated arrow represented in FIG. 7. Thus, any residual defect of the inner surface 13 of the casing 12 is not transmitted by the rigid panel 20 to its wall 28, and has no consequence on the positioning of its wall 28.

[0087] In addition, this configuration allows the use of a standard composite panel 20 whose rims 30 require no machining. A simple selection of the composite panel in a stock of composite panels of different heights makes it possible to find the one whose height H can be suitable for the block 18, without the height of its rims 30 exceeding the height E1 of the block 18.

[0088] The first and fifth steps ET1 to ET6 of the method for manufacturing the support panel 14 according to the invention, comprising especially steps ET1 and ET5 which have been represented in FIGS. 6A and 6B, constitute a first phase P1 of the method for manufacturing the casing with abradable coating 10. Finally, during a second phase P2 of the method for manufacturing the casing with abradable coating 10 which has been represented in FIG. 8 and illustrated in FIG. 7, the support panel 14 is adhered onto the inner surface 13 of the casing and during a third phase P3, the cartridge 16 of abradable material is adhered onto the support panel 14.

[0089] Advantageously, as the variant of the method illustrates it as a dotted line in FIG. 8, the sixth step ET6 for manufacturing the support panel 14 can coincide with the second phase P2 of the method for manufacturing the casing with abradable coating 10, insofar as the adhering of the block 18 to the panel 20 can be done in one single operation at the same time as that of the outer surface 36 of the block 18 on the inner surface 13 of the casing 12. The grouping together of adhesion operations therefore allows to avoid the addition of an additional step to the method, which preserves the same number of steps as methods according to the state of the art, whilst avoiding its disadvantages and without requiring independent cooking to fix the panel 20 to the block 18 and to fix the block 20 to the casing 12.

[0090] The invention is particularly applied to a support panel 14 intended to provide a casing with abradable coating 10 with a turbine engine, whether a casing with abradable coating 10 intended for a compressor path or turbine of said turbine engine.