Flexible retention assembly for turbomachine rotating part burst test bench

Abstract

The invention relates to a flexible retention assembly (4) for a test bench (1) for bursting a rotating part of a turbomachine to be tested (9), said test bench (1) comprising a hollow cylindrical wall (10) defining an internal test tank having a first hollow cylindrical volume (V1) extending along a longitudinal axis (L), a drive shaft (2) mounted to rotate about said longitudinal axis (L) and on which said rotating part to be tested (9) is intended to be fixed, said test bench (1) further comprising means for retaining fragments from said rotating part to be tested (9), said means for retaining fragments comprising: a hard retention assembly (3) intended to be housed in said first hollow internal volume (V1) and comprising at least one hard retention element (30) of hollow cylindrical shape defining a second hollow cylindrical internal volume (V2) intended to extend along said longitudinal axis (L);said flexible retention assembly (4), said flexible retention assembly (4) comprising at least one flexible retention element (40, 40') of hollow cylindrical shape extending along a longitudinal axis (X) and defining a third hollow cylindrical internal volume (V3), said at least one flexible retention element (40, 40') comprising at least one layer of composite material (5).;

Description

Title of the invention: Flexible retention assembly for a turbomachine rotating part burst test bench. Field of the invention

[0001] The present invention relates to the field of aeronautics, and more specifically, to test benches for aircraft turbomachinery.

[0002] More particularly, the invention relates to a test bench for bursting of a rotating part of a turbomachine. Prior art

[0003] In aeronautics, it is known to implement test benches in order to control the risks of bursting of rotating parts, and more particularly of rotating parts of turbomachinery

[0004] Such test benches conventionally comprise a hollow cylindrical wall defining an internal test tank in which is provided a drive shaft mounted movable in rotation around the longitudinal axis of the tank and on which is intended to be fixed the rotating part to be tested.

[0005] Rotating part burst test benches must be able to ensure the retention of fragments of the rotating part that might escape during the bursting of that rotating part. Conventionally, this retention is ensured by two separate elements provided inside the tank: - an internal retention element, called flexible, which is the first element to be impacted by the fragments escaping during the bursting and whose function is therefore to ensure the retention of these fragments without damaging them so as not to distort a subsequent expert assessment; - an external retention element, called hard, which is placed opposite or even in contact with an external surface of the internal element and whose function is to ensure the safety of a user or an installation around the test bench in the event of failure to retain fragments by the internal element.

[0006] It should be noted that by "flexible" and "hard" we mean the ability to deform upon impact with fragments escaping during bursting.

[0007] In other words, the flexible retention element deforms more easily upon impact with fragments than the hard retention element so as to retain these fragments without damaging them, while the hard retention element deforms less easily upon impact with fragments than the flexible retention element so as to ensure the safety of a user or an installation around the test bench.

[0008] A flexible retention element generally takes the form of a hollow cylinder or a circular ring with a predefined thickness depending on the required or desired retention capacity of this flexible retention element. It may, in particular, be made of aluminum to provide satisfactory deformation capacity while maintaining retention qualities suitable for its intended use.

[0009] Nowadays, the materials developed for rotating parts of turbomachinery are increasingly resistant, and consequently, the speeds and energies required for a rotating part to break are increasingly greater. Therefore, the retention capacity of a test bench must be increased accordingly.

[0010] However, increasing the thickness of current flexible retention elements is limited by the problem of integrating them into the test bench and, as a result, the retention capacity for a given test bench may not be sufficient to meet the requirements of a test.

[0011] There is therefore a need to provide a solution to improve such test benches in order to meet the retention capacity requirements of a turbomachine rotating part burst test bench. Description of the invention

[0012] The invention aims to remedy at least in part the disadvantages mentioned above relating to prior art techniques.

[0013] To this end, the invention relates to a flexible retention assembly for a test bench for the bursting of a rotating part of a turbomachine to be tested, said test bench comprising a hollow cylindrical wall defining an internal test chamber having a first hollow cylindrical volume VI extending along a longitudinal axis L, a drive shaft mounted to rotate about said longitudinal axis L and on which said rotating part to be tested is intended to be fixed, said test bench further comprising means for retaining fragments from said rotating part to be tested, said fragment retention means comprising: - a rigid retention assembly intended to be housed in said first hollow internal volume VI and comprising at least one rigid retention element of hollow cylindrical shape defining a second hollow cylindrical internal volume V2 intended to extend along said longitudinal axis L; - said flexible retention assembly,

[0014] said flexible retention assembly comprising at least one flexible retention element of hollow cylindrical shape extending along a longitudinal axis X and defining a third hollow cylindrical internal volume V3, said at least one flexible retention element comprising at least one layer of composite material.

[0015] Thus, the solution proposes a new and inventive approach that makes it possible to resolve at least in part some of the drawbacks of the prior art.

[0016] Indeed, by implementing at least one flexible retention element comprising at least one layer of composite material, it is possible to increase the retention capacity of a test bench while not increasing or only slightly increasing the thickness of current flexible retention elements and thus solving the space problem within the test bench tank.

[0017] In addition, such a composite material makes it possible to limit the deterioration of the fragments so as not to distort a subsequent expert assessment.

[0018] According to a particular aspect of at least one embodiment of the invention, said at least one layer of composite material comprises one fiber among: - a polyaramid fiber; - a very high molecular weight polyethylene fiber.

[0019] According to a particular aspect of at least one embodiment of the invention, said fiber is a fiber among a woven fiber and a non-woven fiber, and in that said fiber is formed by layering material in a unidirectional or bidirectional manner.

[0020] According to a particular aspect of at least one embodiment of the invention, the flexible retention element comprises a plurality of radially superimposed layers of composite material.

[0021] This makes it possible to improve the retention capacity while providing more flexibility in order to limit the risks of damage to fragments escaping during bursting.

[0022] According to a particular aspect of at least one embodiment of the invention, each of said layers of composite material is formed by stacking a plurality of rows of unit elements of composite material along said longitudinal axis X, said rows being stacked in a staggered pattern.

[0023] In this way, it is possible to limit mechanical weaknesses by not aligning the ends of the unitary elements of composite material in columns.

[0024] According to a particular aspect of at least one embodiment of the invention, said flexible retention assembly comprises several flexible retention elements, and for two successive flexible retention elements, a row of unitary elements of composite material of a first of the two successive flexible retention elements in contact with a row of unitary elements of composite material of a second of the two successive flexible retention elements is arranged in a staggered pattern with the row of unitary elements of composite material of the second of the two successive flexible retention elements.

[0025] According to a particular aspect of at least one embodiment of the invention, for two successive layers of composite material, the stacking of said unit elements of composite material of a first of said two successive layers of composite material is offset radially and longitudinally from the stacking of said unit elements of composite material of a second of the two successive layers of composite material so that each joint line between said unit elements of composite material of the first of the two successive layers of composite material is offset radially and longitudinally from each joint line between said unit elements of composite material of said second of said two successive layers of composite material.

[0026] In this way, it is possible to limit mechanical weaknesses by not aligning the ends of the unitary elements of composite material of two successive rows of composite material.

[0027] According to a particular aspect of at least one embodiment of the invention, said layers of composite material are separated two by two by a radial gap.

[0028] According to a particular aspect of at least one embodiment of the invention, the flexible retention element further comprises a structure formed of a second material different from said layer of composite material and provided at the location of said radial gap so that said structure is intercalated between two layers of composite material.

[0029] According to a particular aspect of at least one embodiment of the invention, the structure belongs to the group comprising: a foam; a honeycomb structure; a plurality of tubes extending longitudinally along the X axis; a plurality of sheet metal sheets.

[0030] According to a particular aspect of at least one embodiment of the invention, said at least one flexible retention element is formed at least in part by a stacking of layers of composite material along said longitudinal axis X.

[0031] According to a particular aspect of at least one embodiment of the invention, said stack of layers of composite material is held together by means of at least one tie rod.

[0032] According to a particular aspect of at least one embodiment of the invention, said at least one flexible retention element is radially divided into a plurality of sectors.

[0033] According to a particular aspect of at least one embodiment of the invention, said at least one flexible retention element has a thickness contained between a an internal radial cylinder and an external radial cylinder with a diameter between 50mm and 200mm.

[0034] The invention also relates to a test bench comprising a hollow cylindrical wall defining an internal test chamber having a first hollow cylindrical volume VI extending along a longitudinal axis L, a drive shaft mounted to rotate about said longitudinal axis L and on which said rotating part to be tested is intended to be fixed, said test bench further comprising means for retaining fragments from said rotating part to be tested, said means for retaining fragments comprising: - a rigid retention assembly intended to be housed in said first hollow internal volume VI and comprising at least one rigid retention element of hollow cylindrical shape defining a second hollow cylindrical internal volume V2 intended to extend along said longitudinal axis L; - a flexible retention assembly according to one of the aforementioned embodiments, said flexible retention assembly being intended to be housed in said second hollow internal volume V2 so that said longitudinal axis X of said at least one flexible retention element is coincident with said longitudinal axis L of said first hollow cylindrical volume VI, said drive shaft being mounted in rotation around said longitudinal axis L in said third hollow cylindrical internal volume V3. Presentation of the figures

[0035] The invention, as well as the various advantages it presents, will be more easily understood in the light of the following description of illustrative and non-limiting embodiments thereof, and of the accompanying drawings among which: [Fig.1] is a schematic cross-sectional view of a test bench according to one embodiment of the invention; [Fig.2] is a schematic top cross-sectional view of a test bench according to the embodiment of [Fig.1]; [Fig.3] is a schematic perspective view of a retention element according to one embodiment of the invention; [Fig.4] is a partial schematic side section view of a test bench according to the embodiment of [Fig.1]; [Fig.5] is a partial schematic view of a retention element according to the embodiment of [Fig.3]; [Fig.6] is a partial schematic side-section view of a test bench according to a second embodiment; [Fig. 7] is a partial schematic side-section view of a test bench according to the second embodiment, and [Fig.8] is a schematic top cross-sectional view of a test bench according to the second embodiment.

[0036] Detailed description of an embodiment of the invention

[0037] It should be noted that the invention applies to any type of test bench for performing burst tests on rotating parts. More particularly, the invention is presented in relation to the field of aeronautics, and more specifically to burst tests of rotating parts of turbomachinery.

[0038] These rotating parts of a turbomachine can, for example, be turbine or compressor discs which can be fitted with blades.

[0039] A first embodiment of the invention is now presented in relation to figures 1 to 5.

[0040] As illustrated, the test bench 1 comprises a hollow cylindrical wall 10 defining an internal test tank extending along a longitudinal axis L.

[0041] This internal test tank has a first hollow cylindrical volume V1 which defines the volume available both for carrying out the tests and for implementing the fragment retention assemblies from the rotating part.

[0042] The hollow cylindrical wall can for example be made of metal capable of withstanding impacts with fragments that could escape from the retention assemblies.

[0043] The test bench also includes a drive shaft 2 mounted movable in rotation around the longitudinal axis L and on which the rotating part to be tested 9 is intended to be fixed. In this way, during burst tests, the part to be tested rotates around the longitudinal axis of the cylindrical tank so as to be substantially centered on the inner tank.

[0044] Since some tests also need to be carried out at a higher temperature than ambient temperature, the test bench may also include an annular furnace formed around the drive shaft 2 and configured to surround the rotating part to be tested so as to raise its temperature.

[0045] In order to be able to ensure the retention of fragments of the rotating part which would escape during the bursting of this rotating part, said test bench 1 further comprising means for retaining fragments from the rotating part to be tested 9.

[0046] These means for retaining fragments include: - a rigid retention assembly 3 intended to be housed in the first hollow internal volume VI and comprising at least one rigid retention element 30 of hollow cylindrical shape defining a second hollow cylindrical interior volume V2 intended to extend along the longitudinal axis L; - a flexible retention assembly 4 intended to be housed in the second hollow internal volume V2 and comprising at least one flexible retention element 40 of hollow cylindrical shape defining a third hollow cylindrical internal volume V3 intended to extend along the longitudinal axis L so that the drive shaft 2 is mounted in rotation around the longitudinal axis L in the third hollow cylindrical internal volume V3.

[0047] It is understood that a hard retention assembly can be formed by stacking several hard retention elements 30 along the longitudinal axis L so as to form a hard retention assembly having a hollow cylindrical shape.

[0048] Similarly, it is understood that a flexible retention assembly can be formed by stacking several flexible retention elements 40 along the longitudinal axis L so as to form a flexible retention assembly having a hollow cylindrical shape.

[0049] In particular, in relation to [Fig.3], a flexible retention element 40 is presented. As can be seen, this flexible retention element 40 is of hollow cylindrical shape and extends along a longitudinal axis X. When this flexible retention element is positioned inside the inner test tank, and more particularly inside the hollow cylindrical inner volume V2, the longitudinal axis X coincides with the longitudinal axis L of the inner tank.

[0050] This flexible retention element 40 can be radially divided into a plurality of sectors 4000 in order to facilitate its placement in the internal test tank and also to facilitate its removal once the tests have been carried out.

[0051] Such a flexible retention element 40 can, depending on the circumstances and the tests to be carried out, have a thickness contained between an internal radially cylinder and an external radially cylinder of between 50mm and 200mm.

[0052] The term radially internal cylinder refers to the radially internal limit of this retention element which defines the third hollow cylindrical internal volume V3. Furthermore, the term radially external cylinder refers to the radially external limit of this flexible retention element, which is therefore opposite the rigid retention assembly.

[0053] According to the invention, in order to increase the retention capacity of the test bench compared to the prior art while not increasing or only slightly increasing the thickness of the flexible retention assembly and limiting the deterioration of the fragments so as not to distort a subsequent expert assessment, the or each flexible retention element 40 comprises at least one layer of composite material 5.

[0054] Figures 4 and 5 illustrate in particular the implementation of such a flexible retention element 40.

[0055] More particularly, in the illustrated embodiment, the flexible retention element comprises a plurality of radially superimposed layers of composite material 5.

[0056] Each of these layers can be composed of a fiber from among a woven fiber or a non-woven fiber and formed by layering material in a unidirectional or bidirectional manner.

[0057] This fiber can, more particularly, be a polyaramid fiber or a very high molecular weight polyethylene fiber which are notably used in the field of ballistic protection and which are therefore suitable for a test bench as presented.

[0058] As can be seen in particular in [Fig.5], in the first embodiment presented, each of said layers of composite material 5 is formed by stacking a plurality of rows of unitary elements of composite material 400 along the longitudinal axis X.

[0059] More precisely, here the plurality of rows of unit elements is stacked in a staggered fashion so that the ends of each of the unit elements are not positioned in continuity with the ends of a unit element arranged opposite it on an adjacent row.

[0060] In this way, it is possible to limit mechanical weaknesses by not aligning the ends of the unit elements of composite material, and therefore the lines of joint between two successive unit elements, of two successive rows of composite material.

[0061] Thus, for a flexible retention assembly 4 comprising several flexible retention elements 40, for two successive flexible retention elements 40, a row of unitary elements of composite material 400 of a first of the two successive flexible retention elements 40 in contact with a row of unitary elements of composite material 400 of a second of the two successive flexible retention elements 40 is arranged in a staggered pattern with the row of unitary elements of composite material 400 of the second of the two successive flexible retention elements 40.

[0062] These elements here have a portion-of-a-cylinder shape so as to facilitate stacking and therefore the manufacture of the crown-shaped retention element 40.

[0063] To further limit the mechanical weaknesses of these retention elements 40, and as seen in [Fig.5], the ends of each of the unit elements are not positioned opposite radially and longitudinally the ends of a unit element of a directly successive layer.

[0064] Therefore, and as illustrated in [Fig. 5], for two successive layers of composite material 5M, 5N, the stacking of the unit elements of composite material 400 of a first 5M of the two successive layers of composite material 5 is offset radially and longitudinally from the stacking of the unit elements of composite material 400 of a second 5N of the two successive layers of composite material 5. Thus, in this way, each joint line between the unit elements of composite material 400 of the first 5M of the two successive layers of composite material 5 is offset radially and longitudinally from each joint line between the unit elements of composite material 400 of the second 5N of the two successive layers of composite material 5.

[0065] As can be seen in [Fig.4], in this first embodiment, the layers of composite material 5 are separated two by two by a radial gap.

[0066] In other words, in this embodiment, there is an alternation between layers of composite material and a radial gap.

[0067] This radial gap is here filled by a structure formed of a second material different from the composite material layer.

[0068] In other words, the flexible retention element 40 further comprises a structure 6 formed of a second material different from the layer of composite material and provided at each of the radial gaps so that this structure is intercalated between two successive layers of composite material.

[0069] In other words, the retention element 40 is radially formed by layers of composite material and a structure formed of a second material different from this layer of composite material.

[0070] According to various possible solutions, this structure may belong to the group comprising: - a foam; - a honeycomb structure; - a plurality of hollow or solid tubes extending longitudinally along the X-axis; - a plurality of sheet metal plates.

[0071] This structure can, for example, be formed from a metallic alloy such as an aluminum alloy.

[0072] It can also be formed from an alloy between a composite material and a metallic material.

[0073] A second embodiment of the invention is now presented in relation to Figures 6 to 8.

[0074] As illustrated, in this second embodiment, the flexible retention element or each 40' also comprises several layers of composite material 5'.

[0075] However, and contrary to the first embodiment in which the flexible retention element comprises a plurality of radially superimposed layers of composite material, the flexible retention element 40' presented in the second embodiment of the realization is formed at least in part by a stacking of layers of composite material 5' along the longitudinal axis X.

[0076] As a result, when the retention assembly of this embodiment is positioned inside the second hollow internal volume V2, instead of having a horizontal superposition of the layers of composite material as in the first embodiment, the layers of composite material 5' are here superimposed longitudinally, i.e. vertically.

[0077] To ensure the density and strength of this retention element 40', i.e. by holding the layers of composite material 5' against each other, the stack of layers of composite material 5' is held clamped by means of at least one tie rod 500.

[0078] As illustrated in [Fig.8], in this embodiment, the stack of composite material layers 5' is held together by means of a plurality of radially uniformly distributed tie rods 500 over the surface of the retention element so as to uniformize the forces applied on these tie rods and to optimize the retention of the composite material layers.

[0079] Here again, the flexible retention element can be radially divided into a plurality of 4000 sectors in order to facilitate its placement in the internal test tank and also to facilitate its removal once the tests have been carried out.

[0080] In addition, such a flexible retention element can, depending on the circumstances and the tests to be carried out, have a thickness contained between an internal radially cylinder and an external radially cylinder of between 50mm and 200mm.

Claims

Demands

1. Flexible retention assembly (4) for a test bench (1) for bursting a rotating part of a turbomachine to be tested (9), said test bench (1) comprising a hollow cylindrical wall (10) defining an internal test chamber having a first hollow cylindrical volume (VI) extending along a longitudinal axis (L), a drive shaft (2) mounted to rotate about said longitudinal axis (L) and on which is intended to be fixed said rotating part to be tested (9), said test bench (1) further comprising means for retaining fragments from said rotating part to be tested (9), said means for retaining fragments comprising: - a hard retention assembly (3) intended to be housed in said first hollow internal volume (VI) and comprising at least one hard retention element (30) of hollow cylindrical shape defining a second hollow cylindrical internal volume (V2) intended to extend along said longitudinal axis (L);- said flexible retention assembly (4) intended to be housed in said second hollow internal volume (V2), said flexible retention assembly (4) comprising at least one flexible retention element (40, 40') of hollow cylindrical shape extending along a longitudinal axis (X) and defining a third hollow cylindrical internal volume (V3), said at least one flexible retention element (40, 40') comprising at least one layer of composite material (5).;

2. Flexible retention assembly (4) according to claim 1, characterized in that said at least one layer of composite material (5) comprises a fiber from among: - a polyaramid fiber; - a very high molecular weight polyethylene fiber.

3. Flexible retention assembly (4) according to claim 2, characterized in that said fiber is a fiber among a woven fiber and a non-woven fiber, and in that said fiber is formed by layering material in a unidirectional or bidirectional manner.

4. A flexible retention assembly (4) according to any one of the preceding claims, characterized in that said flexible retention element (40) comprises a plurality of radially superimposed layers of composite material (5).

5. Flexible retention assembly (4) according to the preceding claim, characterized in that each of said layers of composite material (5) is formed by stacking a plurality of rows of unitary elements of composite material (400) along said longitudinal axis (X), said rows being stacked in a staggered pattern.

6. Flexible retention assembly (4) according to the preceding claim, comprising several flexible retention elements (40), characterized in that for two successive flexible retention elements (40), a row of unitary elements of composite material (400) of a first of the two successive flexible retention elements (40) in contact with a row of unitary elements of composite material (400) of a second of the two successive flexible retention elements (40) is arranged in a staggered pattern with said row of unitary elements of composite material (400) of said second of the two successive flexible retention elements (40).

7. A flexible retention assembly (4) according to any one of claims 5 or 6, characterized in that for two successive layers of composite material (5M, 5N), the stacking of said unit elements of composite material (400) of a first (5M) of said two successive layers of composite material (5) is offset radially and longitudinally from the stacking of said unit elements of composite material (400) of a second (5N) of the two successive layers of composite material (5) such that each joint line between said unit elements of composite material (400) of said first (5M) of said two successive layers of composite material (5) is offset radially and longitudinally from each joint line between said unit elements of composite material (400) of said second (5N) of said two successive layers of composite material (5).

8. Flexible retention assembly (4) according to any one of claims 4 to 7, characterized in that said layers of composite material (5) are separated two by two by a radial gap.

9. A flexible retention assembly (4) according to claim 8, characterized in that said retention element (40) further comprises a structure (6) formed of a second material different from said composite material layer (5) and provided at the location of said gap radial so that said structure is sandwiched between two layers of composite material (5).

10. Flexible retention assembly (4) according to any one of claims 1 to 3, characterized in that said at least one flexible retention element (40') is formed at least in part by a stacking of layers of composite material (5') along said longitudinal axis (X).

11. Flexible retention assembly (4) according to the preceding claim, characterized in that said stack of layers of composite material (5') is held clamped by means of at least one tie rod (500).

12. Flexible retention assembly (4) according to any one of the preceding claims, characterized in that said at least one flexible retention element (40) is radially divided into a plurality of sectors (4000).

13. Flexible retention assembly (4) according to any one of the preceding claims, characterized in that said at least one flexible retention element (40) has a thickness contained between an internal radially cylinder and an external radially cylinder of between 50mm and 200mm.

14. Test bench (1) comprising a hollow cylindrical wall defining an internal test tank (10) having a first hollow cylindrical volume (VI) extending along a longitudinal axis (L), a drive shaft (2) mounted movablely to rotate about said longitudinal axis (L) and on which is intended to be fixed said rotating part to be tested (9), said test bench (1) further comprising means for retaining fragments from said rotating part to be tested (9), said means for retaining fragments comprising: - a hard retention assembly (3) intended to be housed in said first hollow internal volume (VI) and comprising at least one hard retention element (30) of hollow cylindrical shape defining a second hollow cylindrical internal volume (V2) intended to extend along said longitudinal axis (L);- a flexible retention assembly (4) according to any one of claims 1 to 13, said flexible retention assembly being intended to be housed in said second hollow internal volume (V2) such that said longitudinal axis (X); said at least one flexible retention element (40) is coincident with said longitudinal axis (L) of said first hollow cylindrical volume (VI), said drive shaft (2) being mounted in rotation about said longitudinal axis (L) in said third hollow cylindrical interior volume (V3).

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