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 defining an internal test tank (10) 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 ring (40, 40', 40'', 40''') of hollow cylindrical shape extending around a longitudinal axis (X) and defining a third hollow cylindrical internal volume (V3), said at least one flexible retention ring (40, 40', 40'', 40''') comprising at least one shear-thickening fluid (6).;

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 around 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 around 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 around a longitudinal axis X and defining a third hollow cylindrical internal volume V3, said at least one flexible retention element comprising at least one shear-thickening fluid.

[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] By implementing at least one flexible retention element comprising at least one shear-thickening fluid, it is possible to increase the retention capacity of a test bench without significantly increasing the thickness of existing flexible retention elements, thus solving the space problem within the test bench tank. Indeed, the characteristic of a shear-thickening fluid is its thixotropic behavior; that is, its viscosity increases as the shear rate increases. This fluid exhibits the unique characteristic of changing its mechanical behavior depending on whether it is deformed slowly or rapidly. When handled slowly, this fluid is in a state between liquid and paste, but when subjected to an impact, it hardens to absorb and disperse the energy before instantly returning to its flexible state.In the event of the bursting of a rotating part inside a test bench, the fragments ejected with high energy subject this shear-thickening fluid at high speed, whose viscosity and retention capacity increase instantaneously.

[0017] Furthermore, such a shear-thickening fluid limits the deterioration of the fragments so as not to skew subsequent analysis. Indeed, after impact, the shear-thickening fluid returns to a liquid or paste-like state, and therefore it is not necessary to descale the fragments received for analysis with caustic soda.

[0018] According to a particular aspect of at least one embodiment of the invention, said at least one flexible retention element is formed by a plurality of walls between which said shear-thickening fluid is provided.

[0019] According to a particular aspect of at least one embodiment of the invention, said plurality of walls is made from a metallic alloy, preferably from an aluminum alloy.

[0020] This helps to limit the deterioration of the fragments so as not to distort a subsequent expert assessment.

[0021] According to a particular aspect of at least one embodiment of the invention, said walls are assembled in the form of a plurality of unit elements each having a form of portion of cylinder and each delimiting a housing inside which is contained said shear-thickening fluid, said at least one flexible retention element having a crown shape formed by juxtaposition of a plurality of unit elements around said longitudinal axis X.

[0022] According to a particular aspect of at least one embodiment of the invention, said unit elements comprise sealing means so as to keep said shear-thickening fluid inside said housing.

[0023] According to a particular aspect of at least one embodiment of the invention, the flexible retention assembly comprises at least two flexible retention rings superimposed one on top of the other along the longitudinal axis X such that said unitary elements of the first of said two flexible retention rings and of the second of said two flexible retention rings are stacked in a staggered pattern.

[0024] In this way, it is possible to limit mechanical weaknesses by not aligning the ends of the unit elements on the same column. According to a particular aspect of at least one embodiment of the invention, said walls are provided in the form of tubes extending along said longitudinal axis X and radially distributed in several rows of tubes, said shear-thickening fluid being provided inside said tubes.

[0025] According to a particular aspect of at least one embodiment of the invention, said rows of tubes are radially separated from each other by aluminum sheets.

[0026] According to a particular aspect of at least one embodiment of the invention, said walls are provided in the form of concentric cylinders extending along said longitudinal axis X and between which said shear-thickening fluid is provided.

[0027] According to a particular aspect of at least one embodiment of the invention, said walls are provided in the form of corrugated sheets extending along said longitudinal axis X and between which said shear-thickening fluid is provided.

[0028] 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.

[0029] 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 an internal radially cylinder and an external radially cylinder of between 50mm and 200mm.

[0030] The invention relates to a test bench comprising: - a hollow cylindrical wall defining an internal test tank having a first hollow cylindrical volume VI extending along a longitudinal axis L; - a drive shaft mounted to rotate freely around said longitudinal axis L and on which said rotating part to be tested is intended to be fixed; - an annular oven formed around said drive shaft and intended to surround and heat said rotating part to be tested during the tests, - means for retaining fragments originating 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 interior volume V2 intended to extend along said longitudinal axis L; - a flexible retention assembly according to one of the aforementioned embodiments, 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.

[0031] According to a particular aspect of at least one embodiment of the invention, the test bench further comprises said cooling means for said flexible retention assembly.

[0032] By implementing cooling means for the flexible retention assembly, heating of the flexible retention assembly is limited, and it thus retains its mechanical retention properties. This makes it possible to increase the retention capacity of a test bench without increasing, or only slightly increasing, the thickness of current flexible retention elements, and therefore to solve the space problem within the test bench tank.

[0033] According to a particular aspect of at least one embodiment of the invention, said cooling means of said flexible retention assembly are connected to an external cooling source. Presentation of the figures

[0034] 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 set of retention elements forming a crown according to the first embodiment of the invention; [Fig.4] is a schematic perspective view of a retention element according to a first embodiment of the invention; [Fig.5] is a sectional view AA of [Fig.4]; [Fig.6] is a schematic top cross-sectional view of a retention element according to a second embodiment of the invention; [Fig. 7] is a schematic top cross-sectional view of a retention element according to a third embodiment of the invention, and [Fig.8] is a schematic top cross-sectional view of a retention element according to a fourth embodiment of the invention.

[0035] Detailed description of an embodiment of the invention

[0036] 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.

[0037] These rotating parts of a turbomachine can, for example, be turbine or compressor discs which can be fitted with blades.

[0038] A first embodiment of the invention is now presented in relation to figures 1 to 5.

[0039] As illustrated, the test bench 1 comprises a hollow cylindrical wall 10 defining an internal test tank extending along a longitudinal axis L, in other words around this longitudinal axis L.

[0040] 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.

[0041] The hollow cylindrical wall can for example be made of metal capable of withstanding impacts with fragments that could escape from the retention assemblies.

[0042] 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.

[0043] 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.

[0044] 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 includes means for retaining fragments from the rotating part to be tested 9.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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, more precisely in the shape of a crown, 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.

[0049] This flexible retention element 40 can be radially divided into a plurality of sectors 400 in order to facilitate its placement in the internal test tank and also to facilitate its removal once the tests have been carried out.

[0050] 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.

[0051] 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.

[0052] 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 comprises at least a shear-thickening fluid 6.

[0053] Figures 1 to 5 illustrate in particular a first embodiment of the invention.

[0054] As illustrated, in this embodiment, the flexible retention element 40 is formed by a plurality of walls 5 between which the shear-thickening fluid 6 is provided.

[0055] These walls are here formed from an aluminum alloy so that the modulus of elasticity is sufficiently low compared to that of the rotating part to be tested.

[0056] According to other embodiments, the walls could be formed from another metallic alloy, a composite material or a polymer having mechanical properties adapted to the conditions of retention and / or perforation.

[0057] As illustrated in figures 4 and 5, the walls 5 are assembled in the form of a plurality of unit elements 400 each having a portion-cylinder shape and each delimiting a housing inside which the shear-thickening fluid 6 is contained.

[0058] In other words, each unit element 400 has an upper wall, a lower wall, and four side walls so as to form a closed and hollow cylindrical portion, inside which is contained said shear-thickening fluid 6.

[0059] In this embodiment, each flexible retention element 40 has a crown shape and is formed by juxtaposing a plurality of unit elements 400 around the longitudinal axis X.

[0060] Furthermore, in this embodiment, the stacking along the longitudinal axis X of a plurality of flexible retention elements is carried out so that the unit elements of two flexible retention elements are staggered.

[0061] In other words, the flexible retention assembly 4 comprises at least two flexible retention rings superimposed one on top of the other along the longitudinal axis X such that the unit elements 400 of the first of the two flexible retention rings and of the second of the two flexible retention rings are stacked in a staggered pattern.

[0062] This staggered arrangement ensures that the ends of each unit element are not positioned in line with the ends of a unit element provided opposite it on an adjacent flexible retention element along the X axis. In this way, it is possible to limit mechanical weaknesses by not aligning the ends of the unit elements.

[0063] So that the shear-thickening fluid does not escape from the housing formed by the interior of these unit elements 400, these unit elements 400 here include sealing means.

[0064] More particularly, these sealing means can take the form of joints provided at each end of the walls forming each unit element so that the lines of joint between two walls are sealed.

[0065] A second embodiment of the invention is now presented in relation to [Fig.6].

[0066] As illustrated, in this second embodiment, and instead of a set of unitary elements each having a form of portion of cylinder, at least one flexible retention element 40' is formed of a plurality of tubes 5' extending along the longitudinal axis X and radially distributed in several rows.

[0067] In other words, the walls 5' are provided in the form of tubes 5' extending along the longitudinal axis X and radially distributed in several rows of tubes 5'.

[0068] In this embodiment, therefore, the shear-thickening fluid 6 is provided inside each of the tubes 5'.

[0069] It should be noted that, according to a particular embodiment of the invention, this shear-thickening fluid can circulate through these tubes or even between the tubes within a shear-thickening fluid circulation circuit.

[0070] As can be seen in [Fig.6], the rows of tubes 5' are radially separated from each other by aluminum sheets 51.

[0071] A third embodiment of the invention is now presented in relation to [Fig.7].

[0072] As illustrated, in this third embodiment, the walls 5” are provided in the form of concentric cylinders 5” extending along the longitudinal axis X and between which the shear-thickening fluid 6 is provided.

[0073] Fig. 7 being a close-up of part of the flexible retention element 40”, the The 5" walls appear straight. However, they are curved to form concentric cylinders.

[0074] A fourth embodiment of the invention is now presented in relation to [Fig.8].

[0075] As illustrated, in this fourth embodiment, and instead of walls without deformations as in the third embodiment, the walls 5'” are provided in the form of corrugated sheets extending along the longitudinal axis X and between which the shear-thickening fluid 6 is provided.

[0076] It should be noted that, regardless of the embodiment, the flexible retention assembly may also include means for cooling said at least one flexible retention element.

[0077] Such means may in particular include a heat transfer fluid circulation circuit equipped with an inlet manifold and an outlet manifold and between which is mounted at least one flexible retention element so that the heat transfer fluid circulates through at least one flexible retention element between the inlet manifold and the outlet manifold.

[0078] These cooling means for at least one flexible retention element can also be connected to an external cooling source.

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 defining an internal test chamber (10) having a first hollow cylindrical volume (VI) extending around a longitudinal axis (L), a drive shaft (2) mounted to rotate freely 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 around 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', 40”, 40”') of hollow cylindrical shape extending around a longitudinal axis (X) and defining a third hollow cylindrical internal volume (V3), said at least one flexible retention element (40, 40', 40”, 40’”) comprising at least one shear-thickening fluid (6).;

2. Flexible retention assembly (4) according to the preceding claim, characterized in that said at least one flexible retention element (40) is formed by a plurality of walls (5, 5', 5”, 5'”) between which said shear-thickening fluid (6) is provided.

3. Flexible retention assembly (4) according to the preceding claim, characterized in that said plurality of walls (5, 5', 5”, 5'”) is made from a metallic alloy, preferably from an aluminum alloy.

4. A flexible retention assembly (4) according to claim 2 or 3, characterized in that said walls (5) are assembled in the form of a plurality of unit elements (400), each having a form of portion of cylinder and delimiting each a housing inside which is contained said shear-thickening fluid (6), said at least one flexible retention element (40) having a crown shape formed by juxtaposition of a plurality of unit elements (400) around said longitudinal axis (X).

5. Flexible retention assembly (4) according to the preceding claim, characterized in that said unit elements (400) comprise sealing means so as to retain said shear-thickening fluid inside said housing.

6. Flexible retention assembly (4) according to any one of claims 4 or 5, characterized in that it comprises at least two flexible retention rings superimposed one on top of the other along the longitudinal axis (X) such that said unit elements (400) of the first of said two flexible retention rings and of the second of said two flexible retention rings are stacked in a staggered pattern.

7. Flexible retention assembly (4) according to any one of claims 2 or 3, characterized in that said walls are provided in the form of tubes (5') extending along said longitudinal axis (X) and radially distributed in several rows of tubes (5'), said shear-thickening fluid (6) being provided inside said tubes (5').

8. Flexible retention assembly (4) according to the preceding claim, characterized in that said rows of tubes (5') are radially separated from each other by aluminum sheets (51).

9. Flexible retention assembly (4) according to any one of claims 2 or 3, characterized in that said walls are arranged in the form of concentric cylinders (5”) extending along said longitudinal axis (X) and between which is arranged said shear-thickening fluid (6).

10. Flexible containment assembly (4) according to any one of claims 2 or 3, characterized in that said walls are provided in the form of corrugated sheets (5'") extending along said longitudinal axis (X) and between which is provided said shear-thickening fluid (6).

11. 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 to rotate freely about said longitudinal axis (L) and on which said rotating part to be tested (9) is intended to be fixed; - an annular furnace (7) formed around said drive shaft (2) and intended to surround and heat said rotating part to be tested (9) during the tests, - 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 10, intended to be housed in said second hollow internal volume (V2) such that said longitudinal axis (X) of said at least one flexible retention element (40) coincides with said longitudinal axis (L) of said first hollow cylindrical volume (VI), said drive shaft (2) being mounted for rotation about said longitudinal axis (L) in said third hollow cylindrical internal volume (V3).;

12. Test bench (1) according to the preceding claim, characterized in that it further comprises said cooling means for said flexible retention assembly (4).

13. Test bench (1) according to the preceding claim, characterized in that said cooling means of said flexible retention assembly (4) are connected to an external cooling source.